000
FXUS63 KDTX 190755
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
355 AM EDT SUN MAY 19 2013

.SHORT TERM...TODAY AND TONIGHT

SE MI STILL REMAINS UNDER THE INFLUENCE OF THE HIGH PRESSURE SYSTEM
OVER EASTERN CANADA WHILE A COLD FRONT DROPS INTO THE NORTHERN GREAT
LAKES AND A STATIONARY FRONT ACROSS THE OHIO VALLEY BEGINS MAKING A
MOVE NORTH. THE SOUTHERN BOUNDARY WILL BEGIN FEELING THE INFLUENCE
OF THE LARGE LOW PRESSURE SYSTEM OVER THE PLAINS AND LIFT NORTHWARD
THROUGH THE DAY. WAA IN THE 600 TO 700 MB LAYER WILL PROVIDE A NICE
CAP TODAY HELPING TO PREVENT ANY CONVECTION FROM INITIATING. THE
LINGERING DRY BOUNDARY LAYER WILL HELP AS WELL BUT AS WINDS SHIFT TO
MORE SOUTHERLY TODAY MOISTURE WILL BE INCREASING STEADILY THROUGH
THE DAY. MID LEVEL RIDGE AXIS WILL PASS OVER MI IN THE EVENING
AMPLIFYING IN RESPONSE TO THE DEEPENING TROUGH OVER THE PLAINS.
PRECIP CHANCES WILL EXIST VERY LATE TONIGHT FOR WESTERN LOWER MI AS
THE FRONT LIFTS NORTH...THE NOSE OF THE LLJ APPROACHES...WE ENTER
THE DIFFLUENT REGION OF THE MID LEVEL FLOW AND A SPOKE OF VORTICITY
LOOKS TO ROTATE AROUND THE LOW UP AND THROUGH THE AREA. SOME OF
THESE SHOWERS/THUNDERSTORMS MAY FIND THEIR WAY INTO OUR FAR WESTERN
COUNTIES THUS ONLY MODIFIED AN INHERITED AREA OF SLIGHT CHANCE POPS
HERE. THE DRY AIR OVER SE MI WILL MAKE IT HARD FOR THEM TO MAKE IT
TOO FAR EAST SO MOST LOCATIONS WILL LIKELY REMAIN DRY NOW THROUGH
SUNDAY NIGHT.

&&

.LONG TERM...MONDAY THROUGH SATURDAY

A CLOSED OFF MID LEVEL LOW PRESSURE SYSTEM WILL CONTINUE SPINNING
OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY EARLY IN THE
WORKWEEK. THIS SYSTEM IS FORECAST TO LUMBER SLOWLY EAST AS THE WEEK
PROGRESSES...TRACKING OVER THE WESTERN GREAT LAKES BY WEDNESDAY AND
EVENTUALLY GETTING ABSORBED BY A LARGER NORTHERN WAVE OVER CANADA.
WHEN THIS OCCURS THE CLOSED LOW BECOMES A TROUGH THAT EVENTUALLY
TRACKS THROUGH THE CENTRAL GREAT LAKES REGION ON THURSDAY. MODEL
SOLUTIONS ARE AGAIN VASTLY DIFFERENT IN HANDLING THIS SYSTEM WITH
THE GFS MAINTAINING A SPLIT FLOW AND SLOWER MOVING LOW THROUGH
FRIDAY WHILE THE ECMWF ABSORBS THE LOW QUICKER BUT BRINGS A SHOT OF
NORTHERN STREAM PV ANOMALY THROUGH THE NORTHERN GREAT LAKES THURSDAY
AND FRIDAY. THIS POSES QUITE AN ISSUE REGARDING POPS AS THE TIMING
OF THESE FEATURES WILL BRING PERIODS OF HEAVY RAIN AS WELL AS QUIET
PERIODS DEPENDING ON THE MODEL SOLUTION. GIVEN THE MODEL UNCERTAINTY
WILL NOT VENTURE FAR FROM THE PREVIOUS FORECAST POPS FOR MUCH OF THE
WORK WEEK.

THE MAIN CHANGES TO THE FORECAST WILL BE TO TEMPERATURES. WITH A
LATER ARRIVAL OF SHORTWAVE ENERGY ON MONDAY SUNSHINE SHOULD BE ABLE
TO CREATE A DEEP MIXED LAYER WHICH TAKES ADVANTAGE OF 850 MB
TEMPERATURES IN THE MID TO UPPER TEENS TO BRING DAYTIME HIGHS WELL
INTO THE 80S AWAY FROM THE GREAT LAKES. ALTHOUGH THE MODELS SHOW THE
SURFACE WARM FRONT SINKING SOUTH MONDAY NIGHT WITH SHOWERS AND
THUNDERSTORMS...IT IS PROGGED TO MOVE BACK NORTH ON TUESDAY. THE
PUSH NORTH OF THE WARM FRONT SHOULD BRING ANOTHER DAY WITH HIGHS
REACHING OR EXCEEDING 80 DEGREES AS 850 MB TEMPERATURES REMAIN IN
THE MIDDLE TEENS. THE MAIN FACTOR KEEPING TEMPERATURES DOWN WILL BE
MORE CLOUD COVER AND ONGOING SHOWERS AND THUNDERSTORMS...HOWEVER THE
EXTREME SOUTHERN CWA HAS THE BEST SHOT AT HITTING THE MIDDLE 80S
WITH A BRIEF BREAK IN THE PRECIPITATION AND SOME FILTERED SUNSHINE.
THE SURFACE LOW TRACKS ALONG THE WARM FRONT LAID ACROSS CENTRAL
LOWER MICHIGAN ON WEDNESDAY. TEMPERATURES SHOULD BE ABLE TO GET INTO
THE 70S ONE LAST DAY BEFORE THE COLDEST AIR FILTERS IN BEHIND THE
DEPARTING LOW BY THE LATE PART OF THE WEEK. HIGH TEMPERATURES BEHIND
THE LOW ARE ONLY EXPECTED TO GET INTO THE 60S FOR THE LATE PART OF
THE WEEK AND INTO THE WEEKEND.

THIS COMPLEX SYSTEM WILL BRING SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS TO THE AREA DURING THE MONDAY THROUGH THURSDAY TIME
FRAME. MUCAPE VALUES WILL BUILD UP TO AROUND 2000 J/KG MONDAY AND
TUESDAY...INCREASING THE CHANCE FOR SEVERE WEATHER ACROSS SOUTHEAST
MICHIGAN. WITH SOUTHEAST SURFACE WINDS AND SOUTHWESTERLY WINDS ALOFT
THERE WILL BE QUITE A BIT OF DIRECTIONAL SHEAR IN THE LOWEST LEVELS
DURING THIS TIME...HOWEVER SPEED SHEAR IS NOT ALL THAT IMPRESSIVE ON
MONDAY AS SPEEDS IN THE COLUMN STRUGGLE TO REACH 20 KNOTS. TUESDAY
IS A DIFFERENT STORY WITH BETTER SPEED SHEAR IN ADDITION TO THE
DIRECTIONAL SHEAR AND MORE IMPRESSIVE HODOGRAPHS WITH HELICITY
VALUES EXCEEDING 300 AND EHI VALUES OF 2 TO 3. THE KEY FACTOR TO THE
SEVERE WEATHER POTENTIAL ON TUESDAY WILL BE IF A BREAK IN THE
ACTIVITY OCCURS AND BREAKS IN THE CLOUDS ALLOW FOR DESTABILIZATION
DURING THE AFTERNOON HOURS. THIS WOULD INCREASE THE THREAT FOR
SEVERE WEATHER...WHILE ONGOING ACTIVITY THROUGHOUT THE DAY WOULD
INHIBIT THE THREAT. IN ADDITION TO THE SEVERE WEATHER THREAT...HEAVY
RAIN WILL ALSO BE A THREAT AS PWAT VALUES REACH 1.80 TO 1.90 INCHES.

WITH A WEAKENING SYSTEM THE THREAT FOR ORGANIZED SEVERE WEATHER
WANES ON WEDNESDAY...HOWEVER MUCAPE VALUES LINGERING IN THE 1500
J/KG RANGE WILL CONTINUE THE THREAT FOR THUNDERSTORMS INTO WEDNESDAY
AS THE LOW TRACKS ALONG THE FRONTAL BOUNDARY. BY THURSDAY MUCAPE
VALUES SHRINK TO A FEW HUNDRED J/KG...WITH THE THREAT FOR AN
ISOLATED THUNDERSTORM EMBEDDED IN THE MAIN AREA OF SHOWERS BEING THE
MAIN THREAT ACROSS THE SOUTHERN CWA. HIGH PRESSURE EVENTUALLY ENDS
THE THREAT FOR PRECIPITATION FRIDAY AND SATURDAY AS A
COOL...DRY...STABLE AIRMASS SETTLES OVER THE CENTRAL GREAT LAKES
REGION.

&&

.MARINE...

WEAK SOUTHEASTERLY FLOW OVER THE LAKES WILL PROVIDE FAVORABLE MARINE
CONDITIONS THROUGH TONIGHT. A LOW PRESSURE SYSTEM OVER THE CENTRAL
PLAINS WILL DRIFT TOWARD THE GREAT LAKES LAYING OUT A WARM FRONT
ACROSS CENTRAL MI. THIS FRONT WILL STALL OVER THE AREA THROUGH
MIDWEEK AS THE LOW TRACKS ALONG IT. WINDS SOUTH OF THE FRONT WILL
REMAIN SOUTHERLY WHILE WINDS TO THE NORTH WILL BACK TO THE EAST AND
INCREASE SLIGHTLY. THIS WILL LEAD TO HIGHER WAVES OVER NORTHERN LAKE
HURON WHILE THE SOUTHERN BASIN...LAKE ST CLAIR AND LAKE ERIE KEEP
WAVES GENERALLY UNDER 2 FEET. THIS LOW WILL BRING A CHANCE OF
THUNDERSTORMS MONDAY THROUGH THURSDAY. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS.

&&

.AVIATION...ISSUED 1149 PM EDT SAT MAY 18 2013

//DISCUSSION...

A REGION OF VERY DRY LOW LEVEL AIR CIRCULATING AROUND THE HIGH
PRESSURE SYSTEM TO THE EAST OF THE REGION HAS HELD SURFACE DEWPOINTS
IN THE 40S ACROSS MUCH OF THE AREA THIS EVENING. THE LOW LEVEL FLOW
WILL TURN MORE TOWARD THE SOUTHEAST DURING THE COURSE OF THE MORNING
WHICH WILL ADVECT THE MID TO UPPER 50S DEWPOINTS NOW OVER NORTH
CENTRAL OHIO INTO SE MI. IT NOW APPEARS THAT THE BULK OF THE SURFACE
MOISTURE ADVECTION WILL OCCUR AFTER DAYBREAK. THIS SUPPORTS THE
REMOVAL OF ANY MENTION OF HAZE IN THE TAFS. OTHERWISE...AN UPPER
LEVEL RIDGE WILL MAINTAIN BENIGN AVIATION WEATHER CONDITIONS THROUGH
THE AFTERNOON.

//DTW THRESHOLD THREATS...

* NONE

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK
AVIATION.....SC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 190731
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 AM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 330 AM EDT SUN MAY 19 2013

FAIR AND MILD WEATHER IS ANTICIPATED TODAY. THE WEATHER PATTERN WILL
BECOME UNSETTLED MONDAY THROUGH WEDNESDAY AS A LOW PRESSURE SYSTEM
OVER THE UPPER MIDWEST BRINGS SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS TO OUR REGION. MILD WEATHER WILL CONTINUE THROUGH
MIDWEEK BEFORE TEMPERATURES COOL TO NEAR NORMAL LATE IN THE WEEK.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 330 AM EDT SUN MAY 19 2013

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE PROBABILITIES
FOR THUNDERSTORMS AND EVALUATE THE POTENTIAL FOR SVR WX MONDAY
THROUGH TUESDAY.

FAIR AND WARM WX WILL CONTINUE TODAY WITH MAX TEMPS RANGING FROM THE
UPPER 70S OVER OUR NORTHERN COUNTIES TO MIDDLE 80S NEAR TO SOUTH OF
I-96. MOST OF TONIGHT SHOULD BE DRY BUT THERE IS A SMALL CHANCE OF A
SHOWER OR STORM TOWARD DAYBREAK MONDAY.

STRONG TO SEVERE STORMS ARE POSSIBLE MONDAY AFTERNOON AND EVENING AS
A CONSENSUS OF LATEST SHORT RANGE GUIDANCE SHOWS POTENTIAL FOR
MODERATE TO STRONG INSTABILITY TO DEVELOP MONDAY AFTERNOON WITH SB
CAPE VALUES POTENTIALLY REACHING AT LEAST 3000 J/KG OVER OUR
SOUTHERN COUNTIES.

DEEP MOISTURE IS LACKING BUT SFC DEW POINTS SHOULD REACH WELL INTO
THE 60S MONDAY. FCST SOUNDINGS SHOW AN INVERTED V TYPE SOUNDING SO
WILL HAVE TO WATCH FOR DAMAGING WIND GUSTS IN ADDITION TO POTENTIAL
FOR LARGE HAIL. THUNDERSTORMS SHOULD CONTINUE MONDAY NIGHT WITH A
WARM FRONTAL BOUNDARY IN THE AREA AND LATEST 00Z ECMWF GUIDANCE
SHOWING POTENTIAL FOR AN MCS TO TRACK AND TRAIN EAST ALONG THE WARM
FRONTAL BOUNDARY OVERNIGHT.

MORE SHOWERS AND STORMS ARE ANTICIPATED TUESDAY ALTHOUGH THE THREAT
FOR SVR WX TUESDAY IS A BIT LOWER THAN MONDAY WITH A CONSENSUS OF
00Z SHORT RANGE GUIDANCE SHOWING LESS IN TERMS OF INSTABILITY AND
MORE CLOUD COVER.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 330 AM EDT SUN MAY 19 2013

LITTLE QUESTION WE WILL START THIS PERIOD OUT WITH AN ACTIVE WEATHER
PATTERN FEATURING SHOWERS AND THUNDERSTORMS INTO WEDNESDAY NIGHT.
THERE IS A SLIGHT RISK THAT SEVERE STORMS COULD STILL HAPPEN INTO
WEDNESDAY EVENING. HOWEVER AS THE MEMORIAL DAY WEEKEND APPROACHES
THE STORY TURNS AROUND AS CANADIAN HIGH PRESSURE BUILDS IN WHICH
THEN BRINGS COOL... DRY WEATHER THROUGH MOST OF THE WEEKEND.

THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE OVERALL PATTERN
BUT THE ECMWF IS MORE AMBITIOUS WITH PHASING THE NORTHERN AND
SOUTHERN STREAM LATE IN THE WEEK. THAT MEANS COLD AIR INVADES THE
AREA IN THE FRIDAY TO SATURDAY TIME FRAME. ENOUGH SO THAT FROST MAY
BE POSSIBLE FRIDAY NIGHT AND SATURDAY NIGHT OVER NORTHERN AREAS.

THE LARGE SCALE UPPER AIR PATTEN FEATURES NUMEROUS CLOSED UPPER LOWS
AT MID LATITUDES ACROSS THE ENTIRE NORTHERN HEMISPHERE. OF INTEREST
TO SOUTHWEST MICHIGAN IS THE CLOSED UPPER LOW OVER THE CENTRAL AND
NORTHERN PLAINS (REX BLOCKED BY A CLOSED UPPER HIGH OVER ALBERTA AND
WESTERN ONTARIO) AND DEEPER CLOSED LOW IN THE GULF OF ALASKA. AS IT
TURNS OUT THE GULF OF ALASKA LOW SENDS SOME ENERGY OVER THE TOP OF
THE UPPER HIGH... RETROGRADING IT THEN ALLOWING IT TO GET ABSORBED
BY THE SUBTROPICAL HIGH OVER SOUTHERN TEXAS BY FRIDAY. MEANWHILE THE
SHORTWAVE THAT HEADS EAST OVER CENTRAL CANADA MERGES WITH SYSTEM
OVER EASTERN CANADA BY THEN. IT THEN STRONGLY DIGGING AN EASTERN
TROUGH BY LATE FRIDAY INTO EARLY SATURDAY. AS ALL OF THAT IS
HAPPENING THE CLOSED LOW OVER THE PLAINS GETS SHEARED OUT AND
ABSORBED BY THE DIGGING NORTHERN STREAM EASTERN CANADA TROUGH.
SOUTHWEST MICHIGAN END UP BETWEEN THE UPPER RIDGE TO OUR WEST AND
THE DEEP TROUGH TO OUR EAST. THAT IS A SET UP FOR COOL DRY WEATHER
HERE.

WHAT ALL OF THIS DOES IS CONTINUE THE THREAT OF SHOWERS AND
THUNDERSTORMS WITH THE FRONT STALLED NEAR SOUTHERN MICHIGAN INTO
WEDNESDAY AFTERNOON. THE LOW LEVEL JET IS AIMED AT SOUTHERN MICHIGAN
TUESDAY NIGHT INTO WEDNESDAY THEN REDEVELOPS OVER WESTERN INDIANA
WEDNESDAY AFTERNOON AS THE UPPER LOW STARTS TO SHEAR OUT. BY 8 PM
WEDNESDAY THERE IS A 35 TO 40 KNOT LOW LEVEL JET AIMED AT SOUTHEAST
MICHIGAN. GIVEN THE PRECIPITABLE WATER IS NEARLY DOUBLE NORMAL (NEAR
1.5 INCHES BY THEN) AND WE HAVE DEEP SOUTHERLY FLOW BEING LIFTED
OVER A STATIONARY FRONT BETWEEN I-94 AND I-96... I AM THINKING WE
WILL HAVE A CONSIDERABLE AMOUNT OF LAYERED CLOUDS AND SHOWERS
AROUND. THAT MAY DECREASE THE THREAT OF SURFACE BASED CONVECTION.
STILL IT WILL HAVE TO BE WATCHED. MUCAPES ARE STILL OVER 1000 J/KG
ON THE GFS WEDNESDAY AFTERNOON. ADD TO THE THE JET ENTRANCE REGION
LIFT AND SEEMS WE HAVE DECENT SET UP FOR SEVERE STORMS. WE WILL HAVE
TO WATCH THIS FOR SURE. THIS COULD BE THE BEST SET UP FOR SEVERE
STORMS OF THE WEEK FOR SOUTHWEST MICHIGAN.

FINALLY THE DIGGING NORTHERN STREAM TROUGH OVER EASTERN CANADA WILL
TAKE OVER AND CLEAR ALL THIS OUT TO OUR EAST. SO THURSDAY SHOULD BE
TRANSITIONAL. THE CANADIAN HIGH MOVES IN FRIDAY INTO SATURDAY SO
CLEAR SKIES...WINDS WILL BE LIGHT AND COOLER TEMPERATURES WILL
PREVAIL. HENCE THE RISK OF FROST UP NORTH FRIDAY NIGHT AND SATURDAY
NIGHT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 716 PM EDT SAT MAY 18 2013

SOME MVFR VISIBILITIES IN FOG MAY DEVELOP FOR ABOUT THREE TO SIX
HOURS TOWARD DAYBREAK SUNDAY. OTHERWISE...VFR CONDITIONS EXPECTED
THROUGH THE FORECAST PERIOD.

&&

.MARINE...
ISSUED AT 330 AM EDT SUN MAY 19 2013

MINIMAL WAVE ACTION IS ANTICIPATED TODAY AND MONDAY BUT SOME AREAS
OF FOG MAY DEVELOP AS A MORE HUMID AIRMASS MOVES IN OVER RELATIVELY
COLD LAKE MI WATERS. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS
MONDAY THROUGH WEDNESDAY.

&&

.FIRE WEATHER...
ISSUED AT 330 AM EDT SUN MAY 19 2013

MILD AND DRY WEATHER WILL CONTINUE TODAY AND INCREASING MOISTURE
WILL CAUSE RELATIVE HUMIDITY VALUES TO BE HIGHER THAN YESTERDAY.
WIND SPEEDS AGAIN TODAY WILL BE FAIRLY LIGHT.

&&

.HYDROLOGY...
ISSUED AT 330 AM EDT SUN MAY 19 2013

SEVERAL ROUNDS OF RAIN AND THUNDERSTORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY. THE STRONGEST STORMS MAY CONTAIN LOCALLY HEAVY RAINFALL
BUT ON AVERAGE AROUND AN INCH TO TWO INCHES OF RAIN IS EXPECTED TO
FALL ACROSS MUCH OF OUR AREA FROM MONDAY THROUGH WEDNESDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...MACZKO
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...LAURENS

000
FXUS63 KAPX 190710
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
310 AM EDT SUN MAY 19 2013

.SYNOPSIS...
ISSUED AT 310 AM EDT SUN MAY 19 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE PLAINS...
BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK. THIS
APPROACHING SYSTEM WILL GENERATE SHOWERS AND THUNDERSTORMS ACROSS
NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM EDT SUN MAY 19 2013

A GRADUAL STEP UP TOWARD A MUCH MORE ACTIVE PERIOD OF WEATHER BEGINS
TODAY...AS SOME SMALL SHOWER CHANCES ENTER THE FORECAST. THE TIMING
AND EVEN EXISTENCE OF THOSE LATER THIS AFTERNOON REMAINS THE PRIMARY
FORECAST ISSUE THROUGH SUNSET...WITH THE FOCUS SHIFTING TOWARD
POSSIBLE ADDITIONAL PRECIP CHANCES OVERNIGHT. THE EARLY MORNING
WEATHER MAP IS STILL A RATHER QUIET ONE FOR NORTHERN MICHIGAN...AS
EXPANSIVE LOW LEVEL RIDGING REMAINS DRAPED FROM NEWFOUNDLAND DOWN
INTO OUR NECK OF THE WOODS. OF MUCH BIGGER INTEREST IS A RATHER
HEALTHY LONGWAVE TROUGH SLOWLY LIFTING FROM THE SOUTHERN ROCKIES
ONTO THE PLAINS...WITH THIS SYSTEM HELPING DRIVE LEE CYCLOGENESIS
ACROSS WESTERN KANSAS WHILE ALSO KICKING OFF SEVERAL COMPLEXES OF
SHOWERS AND SEVERE STORMS. GRADUAL RAMPING UP OF MID LEVEL WARM
ADVECTION ASCENT WELL AHEAD OF THIS TROUGH CONTINUES TO FORCE AN
AXIS OF THICKER CLOUD COVER UP ACROSS THE U.P...WITH EVEN A FEW
SPITS OF RAIN FALLING AT TIMES...THOUGH HINDERED LARGELY BY A
SIGNIFICANT DRY WEDGE BELOW 750MB.

FOR TODAY...NOT MUCH TO SPEAK OF THIS MORNING WITH RIDGING DOWN LOW
STILL IN CONTROL...THOUGH LOSING ITS INFLUENCE WITH TIME AS THE
RIDGE CORE SLIDES OFF THE NORTHEAST COAST. MEANWHILE...SLIGHTLY
BETTER RETURN FLOW SHOULD GET UNDERWAY...PARTICULARLY THIS AFTERNOON
AS A WARM FRONT TRIES TO MAKE SOME NORTHWARD PROGRESS...ALL WHILE
STRONGER LOW PRESSURE TAKES SHAPE ACROSS SOUTH DAKOTA. THE QUESTION
IS WILL WE GET ENOUGH LOWER LEVEL MOISTURE BACK THIS FAR NORTH TO
AID IN FIRING OFF AT LEAST A FEW AFTERNOON SHOWERS. A FEW THINGS
WORKING IN OUR FAVOR INCLUDE DECENT DAYTIME HEATING EXPECTED...WITH
HIGHS WARMING WELL INTO THE 70S AND LOWER 80S...AND WHAT SHOULD BE
NUMEROUS LOCALIZED TRIGGERS/CONVERGENCE AS LAKE BREEZE DEVELOPMENT
BECOMES WIDESPREAD WITH A LIGHT GRADIENT.

WITH THAT SAID...ARRIVAL OF BUILDING SHORTWAVE RIDGING SQUARELY
OVERHEAD WITH TIME DOES GIVE ONE A LITTLE PAUSE WITH POSSIBLE
CAPPING ISSUES...AND THE FACT THAT GUIDANCE MOISTURE PROGS CAN`T BE
TRUSTED DOESN`T HELP. NAM/GFS DEPICTION OF SURFACE DEW POINTS WELL
INTO THE 60S JUST DOESN`T LOOK DOABLE GIVEN THE TRUE WARM FRONT WILL
LIKELY HOLD TO OUR SOUTH THROUGH THE DAY AS IT BENDS AROUND THE COLD
LAKE WATERS. INSTEAD...LOW OR MID 50S LOOK BETTER...SIMILAR TO
THOSE OBSERVED ACROSS NORTHERN INDIANA YESTERDAY. PER FORECAST
RAOBS...AN 80/55 PARCEL MIGHT JUST BE ABLE TO SQUEAK BY THE
CAP...BUT THAT DOESN`T LEAVE A WHOLE LOT OF AVAILABLE INSTABILITY...
EVEN WITH SOME DECENT (NOT GREAT) LAPSE RATES ARRIVING. THE LONG AND
SHORT OF IT IS THE CHANCE FOR A FEW SHOWERS IS NOT COMPLETELY
ZERO...ESPECIALLY WHERE LAKE BREEZE BOUNDARIES CAN PROVIDE SOME
BETTER MOISTURE POOLING...BUT IT`S CERTAINLY NOTHING HIGHER THAN
ABOUT 20 PERCENT. WILL CONTINUE TO HAVE A MENTION BUT CONFIDENCE IS
NOT VERY HIGH. EASTERN UPPER MIGHT ACTUALLY STAND A BETTER SHOT
WITH THE LEAD INVERTED TROUGH AXIS/WARM FRONT PROVIDING SLIGHTLY
BETTER CONVERGENCE...WHILE THE BACKGROUND/SYNOPTIC FLOW FROM THE
SOUTH TRIES TO PIN ANY SHOWERS CLOSER TO THE LAKE SUPERIOR SHORE.

CHANCES ARE MAYBE A LITTLE BETTER THE FIRST HALF OF TONIGHT AS AN
ELEVATED WARM FRONT LIFTS THROUGH THE REGION ROUGHLY 06-12Z...WITH
THE SURFACE FRONTAL BOUNDARY SLIDING NORTH TOWARD THE STRAITS BY
SUNRISE. LOW LEVEL JET FORCING IS NOTHING SPECTACULAR...NOR IS ANY
UPPER JET OR DYNAMIC FORCING...AS MUCH OF THAT IS RELEGATED WELL TO
OUR WEST IN ADVANCE OF THE STRONGER UPPER TROUGH. STILL...COULD BE
ENOUGH ACCELERATION OF THE LOW LEVEL JET UP THE SPINE OF LAKE
MICHIGAN TO HELP FIRE OFF SOME ADDITIONAL SHOWERS ACROSS MAINLY THE
TIP OF THE MITT AND EASTERN U.P. THROUGH 06Z. AN EVEN BETTER CHANCE
SHOULD ARRIVE FOR THOSE AREAS AND PROBABLY NORTHWEST LOWER TOO AFTER
06Z AS A PRONOUNCED THETA-E RIDGE FOLDS OVER INTO THE AREA...WITH
MUCAPE VALUES ON THE SOUTHERN FRINGE OF THE ELEVATED WARM FRONT
RISING TO AROUND 700 J/KG...SUGGESTING A THUNDER THREAT. A MILD
NIGHT EXPECTED...WITH LOWS ONLY IN THE 50S NORTH TO 60S ACROSS MUCH
OF NORTHERN LOWER...SOUTH OF THE WARM FRONT. IN FACT...COULD SEE A
FEW SPOTS CLOSER TO LAKE MICHIGAN HOLD NOT FAR FROM 70 THROUGH MUCH
OF THE NIGHT...AS IS TYPICAL IN THESE SETUPS.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 AM EDT SUN MAY 19 2013

MONDAY THRU WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE
FROM WEST TO EAST MONDAY MORNING AS THE WARM FRONT SAGS SOUTHWARD
INTO NRN LWR MICHIGAN. DEVELOPING LOW PRESSURE IN THE PLAINS WILL
BEGIN TO TAP INTO GULF MOISTURE...ADVECTING IT NORTHWARD THRU THE
LOWER AND MID MISSISSIPPI VALLEY AND INTO THE WRN GREAT LAKES. AS
THIS DEEPER MOISTURE BEGINS TO INTERACT WITH THE WARM FRONT AND A
SERIES OF SHORT WAVES RIDING NE THRU MICHIGAN AHEAD OF THE DEEPENING
UPPER LOWER...SHOWER AND THUNDERSTORM ACTIVITY WILL INCREASE MONDAY
MORNING...WITH LIKELY POPS EXPECTED THRU WEDNESDAY NIGHT. SURFACE
AND CLOSED UPPER LOW BECOME VERTICALLY STACKED...THUS MAKING VERY
SLOW EASTWARD PROGRESS OVER THIS TIME PERIOD...AND THEREFORE KEEPING
OUR WEATHER UNSETTLED THRU MID WEEK. WARM TEMPS WILL HOLD OVER THE
REGION ON MONDAY BEFORE THE WARM FRONT DROPS SOUTH OF OUR CWA ON
TUESDAY AND WEDNESDAY. HIGH TEMPS ON MONDAY WILL RANGE FROM THE MID
TO UPPER 60S ACROSS ERN UPR MICHIGAN NORTH OF THE WARM FRONT TO THE
MID 70S TO LOWER 80S SOUTH OF THE WARM FRONT. HIGH TEMPS WILL ONLY
REACH INTO THE 60S TO NEAR 70 BOTH TUESDAY AND WEDNESDAY AS THE WARM
FRONT CONTINUES TO DROP SOUTH OF OUR CWA.

WEDNESDAY NIGHT THRU SATURDAY...SURFACE AND UPPER LOW CENTERS WILL
SLOWLY SLIDE THRU LWR MICHIGAN WEDNESDAY NIGHT...EXITING EAST TOWARD
NEW ENGLAND THURSDAY. THE THREAT OF THUNDER WILL END WEDNESDAY NIGHT
AS THE SURFACE LOW CENTER SLIDES JUST SOUTH OF OUR CWA. SOME SHOWERS
WILL LINGER ACROSS OUR CWA WEDNESDAY NIGHT AND THURSDAY...BUT SHOULD
COME TO AN END BY THURSDAY NIGHT AS COLDER AND DRIER AIR FILTER INTO
THE REGION BEHIND THE DEPARTING LOW. CORE OF THE COLD AIR WILL
REMAIN WELL NORTH OF MICHIGAN...BUT LIMITED CAA WILL DROP HIGH TEMPS
INTO THE UPPER 50S AND LOWER 60S FOR BOTH THURSDAY AND FRIDAY. NEXT
WEEKEND STILL LOOKS DRY WITH COOLER THAN NORMAL TEMPS AS THE SURFACE
HIGH AND BROAD UPPER LEVEL TROUGHING BOTH REMAIN LOCKED OVER THE
GREAT LAKES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1149 PM EDT SAT MAY 18 2013

VFR.

LIGHT SOUTHERLY FLOW IN PLACE IN THE LOW AND MID LEVELS...BETWEEN
HIGH PRESSURE OVER EASTERN CANADA...AND LOW PRESSURE IN THE CENTRAL/
SOUTHERN HIGH PLAINS. THIS WILL SLOWLY BRING MORE LOW-LEVEL MOISTURE
INTO THE REGION. WEAK DISTURBANCE PASSING ACROSS THE REGION
TONIGHT WILL BRING MID CLOUDS TO THE REGION...AND PERHAPS A
SPRINKLE NEAR PLN. ON SUNDAY...A MIX OF CUMULUS AND LINGERING MID
CLOUDS CAN BE EXPECTED. DEVELOPING LAKE BREEZES WILL LIKELY
TRIGGER A FEW SHRA IN THE AFTERNOON...BUT INLAND FROM ALL THE TAF
SITES.

LIGHT WINDS TONIGHT INTO SUNDAY MORNING...WITH ONSHORE WINDS
DEVELOPING EARLY SUNDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 310 AM EDT SUN MAY 19 2013

A WEAK GRADIENT WILL CONTINUE TO PROVIDE LIGHT WINDS ACROSS THE
WATERS TODAY INTO TONIGHT...BUT WITH EASTERLY FLOW GRADUALLY
STRENGTHENING LATE TONIGHT THROUGH MIDWEEK...NORTH OF A WARM FRONT
STALLING NEARBY. SMALL CRAFT ADVISORIES MAY EVENTUALLY BE
NEEDED...ESPECIALLY LATER MONDAY THROUGH WEDNESDAY...AND
PARTICULARLY IN AND AROUND THE STRAITS WHERE EASTERLY FLOW WILL BE
CHANNELED. HIGH PRESSURE IS EXPECTED TO SLOWLY WORK BACK INTO THE
REGION LATE IN THE WORK WEEK AND TOWARD NEXT WEEKEND...WITH A RETURN
TO LIGHT WINDS.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...MLR
SHORT TERM...LAWRENCE
LONG TERM...MLR
AVIATION...JZ
MARINE...LAWRENCE

000
FXUS63 KGRR 190511
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
111 AM EDT SUN MAY 19 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 311 PM EDT SAT MAY 18 2013

LOW PRESSURE DEVELOPING IN COLORADO WILL TRACK SLOWLY EAST OVER
THE NEXT COUPLE OF DAYS. SOUTHEAST WINDS AHEAD OF THIS SYSTEM WILL
DRAW WARMER AND INCREASINGLY MOIST AIR INTO THE GREAT LAKES
REGION.  AS A RESULT NUMEROUS SHOWERS AND THUNDERSTORMS ARE FORECAST
TO ARRIVE BY MONDAY. THIS UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE MIDDLE PART OF THE WEEK.

&&

.UPDATE...
ISSUED AT 804 PM EDT SAT MAY 18 2013

NO UPDATES TO THE FORECAST THIS EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 311 PM EDT SAT MAY 18 2013

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THUNDERSTORM
AND SEVERE WEATHER POTENTIAL ON MONDAY.

THE COMBINATION OF UPPER LEVEL DIVERGENCE...INCREASING DEEP LAYER
SHEAR...ARRIVAL OF GULF MOISTURE AND BUILDING CAPE SUPPORTS AN
INCREASED RISK FOR ORGANIZED CONVECTION MONDAY INTO MONDAY NIGHT.
MID LEVEL LAPSE RATES STEEPEN TO 7.5 TO 8 DEG C/KM.  A 20 TO 30
KNOT LOW LEVEL JET SETS UP JUST SOUTH OF THE MI BORDER MONDAY AND
STAYS THERE THROUGH MON NIGHT. THIS SHOULD FOCUS THE CONVECTION IN
LOWER MI THROUGH THAT PERIOD. THE SURFACE WARM FRONT WILL BE
LIFTING THROUGH AT THAT TIME WHICH WILL ALSO HELP TO PROVIDE A
FOCUS FOR THE CONVECTION. MODELS ARE IN DECENT AGREEMENT ON THIS
SCENARIO. SO WILL FEATURE NUMEROUS SHOWERS AND THUNDERSTORMS FOR
THIS PERIOD. I SUSPECT WE WILL SEE MORE THAN ON ROUND OF
CONVECTION IN THIS TIME FRAME. RAINFALL COULD BE HEAVY AND REPEAT
OVER THE SAME REGION GIVEN THE FRONTAL ZONE WILL BECOME NEARLY
PARALLEL TO THE MID TO UPPER LEVEL FLOW.

I CONSIDERED ADDING A SMALL CHANCE FOR A STORM SUNDAY AFTERNOON
CLOSER TO THE LAKE SHORE. A LAKE BREEZE WILL TRY TO DEVELOP. WHILE
SOME INSTABILITY WILL BE PRESENT...THE MOISTURE IS STILL SOMEWHAT
LIMITED. THERE IS A WEAK CAP/WARM LAYER NOTED IN FORECAST
SOUNDINGS UP AROUND 650 MB AS WELL. SO WILL KEEP IT DRY. IT WILL
BE A WARM DAY WITH MOST LOCATIONS TOPPING OUT IN THE LOW TO MID
80S. I DID WARM TEMPERATURES UP ALONG THE SHORELINE AS THE FLOW
WILL FEATURE AN OFFSHORE COMPONENT TO START THE DAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT MAY 18 2013

AN ACTIVE WEATHER PATTERN WILL BE UNDERWAY TUESDAY AS A SLOW MOVING
LOW MIGRATES FROM THE PLAINS EASTWARD. A STATIONARY FRONT EXTENDING
EASTWARD FROM THE LOW WILL BE A FOCUS FOR SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. PWAT VALUES NEAR 1.75 INCHES SUGGESTS A HEAVY
RAIN POTENTIAL. MODELS CERTAINLY SHOW QUITE A BIT OF INSTABILITY
WITH LI/S NEAR -8C AND MLCAPE AROUND 2500 J/KG SHEAR VALUES IN THE
45-50KT RANGE POINT TOWARD A SVR POTENTIAL TOO. NO ONE TIME PERIOD
LOOKS MORE FAVORABLE THAN ANOTHER. OF COURSE AFTERNOON INSTABILITY
MAY BE KEY. HOWEVER WITH THE FRONT NEARBY...ELEVATED STORMS COULD BE
POSSIBLE TOO AND BE LESS INFLUENCED BY DAYTIME HEATING. THE LLJ
ISN/T ALL THAT IMPRESSIVE WITH THE SYSTEM BUT MOISTURE TRANSPORT
LOOKS ADEQUATE FOR STORM INITIATION.

AS THE LOW MOVES OVERHEAD WEDNESDAY NIGHT AND THURSDAY WE SHOULD SEE
THUNDERSTORM CHANCES DECREASE IN FAVOR OF SHOWERS. A DRYING TREND
WILL GREET THE BEGINNING OF THE MEMORIAL DAY WEEKEND RESULTING IN PT
CLDY SKIES WITH HIGHS IN THE MID 60S AND LOWS IN THE MID 40S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 110 AM EDT SUN MAY 19 2013

ONE MORE DAY OF SOLID VFR CONDITIONS EXPECTED. I DO EXPECT A LAKE
BREEZE TO DEVELOP THIS AFTERNOON SO I SHIFTED THE WIND TO
SOUTHWEST AT MKG DURING THE EARLY AFTERNOON BUT THE LOW TO MID
LEVEL AIR IS TO DRY TO CREATE MORE THAN FEW CUMULUS CLOUDS EVEN ON
THE LAKE BREEZE.

&&

.MARINE...
ISSUED AT 311 PM EDT SAT MAY 18 2013

WATER TEMPERATURES WILL BE ON THE RISE INTO EARLY NEXT. WHILE WE
HAVE OFFSHORE FLOW...IT IS NOT THAT STRONG. THE FLOW VEERS TO THE
SOUTH AND THE AIR TEMPERATURE WARMS. ALSO MOISTURE WILL BE ON THE INCREASE.
TYPICALLY IN THESE SETUPS WATER TEMPERATURES CLIMB RATHER QUICKLY. WILL
NEED TO MONITOR THE FOG SETUP AS SURFACE DEW POINTS WILL CLIMB INTO
THE 60S. THE STABLE COLDER WATER TEMPERATURES GENERALLY IN THE LOW 40S WILL
LIMIT THE WAVE DEVELOPMENT.


&&

.FIRE WEATHER...
ISSUED AT 311 PM EDT SAT MAY 18 2013
WARM AND DRY INTO SUNDAY. MOISTURE WILL BE ON THE INCREASE AND
THAT WILL KEEP HUMIDITY LEVELS UP. WIND VALUES WILL BE RELATIVELY
LIGHT DUE TO THE WEAKER PRESSURE GRADIENT.

&&

.HYDROLOGY...
ISSUED AT 311 PM EDT SAT MAY 18 2013

GULF MOISTURE WILL BE STREAMING INTO LOWER MICHIGAN THROUGH THE
MIDDLE PART OF THE WEEK. THIS WILL INCREASE THE RISK FOR HEAVIER
RAIN. THE MAIN TIME FRAME FOR POTENTIAL HEAVY RAIN WILL EXIST
BETWEEN MONDAY AND WEDNESDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MACZKO
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...WDM
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KAPX 190349
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1149 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 316 PM EDT SAT MAY 18 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE
PLAINS...BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK.
THIS APPROACHING SYSTEM WILL GENERATE THUNDERSTORMS AND MILD
TEMPERATURES...OVER NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.UPDATE...
ISSUED AT 1013 PM EDT SAT MAY 18 2013

NEWBERRY AND THE SAULTS CONTINUE TO REPORT OCCASIONAL VERY LIGHT
PRECIP. THE RAIN GAGE AT THE SAULT MI ASOS HAS THUS FAR REFUSED TO
CLICK OFF EVEN 0.01 INCH. SO SPRINKLES MAY BE THE BEST
DESCRIPTOR...BUT WITH A CLUSTER OF SOMEWHAT STRONGER RETURNS JUST
WEST OF CHIP/MACK...HAVE MENTIONED SCT -SHRA UP UNTIL 07Z IN
EASTERN UPPER.

MID CLOUDS ARE MAKING A SE-WARD PUSH BACK INTO NORTHERN
LOWER...AND HAVE BECOME MORE WIDESPREAD NORTH OF A TVC-ROGERS
LINE. THE IDEA OF PARTLY CLOUDY SOUTH AND MOSTLY CLOUDY NORTH
STILL LOOKS SOUND...WITH SOME POTENTIAL FOR BUBBLY CU DEBRIS
DOWNSTATE TO BE DRAWN NORTHWARD INTO SOUTHERN SECTIONS OVERNIGHT.

ONLY MINOR TWEAKS TO MIN TEMPS.

UPDATE ISSUED AT 728 PM EDT SAT MAY 18 2013

VERY SPOTTY SPRINKLES/-SHRA RESTRICTED TO EASTERN UPPER MI (MAINLY
CHIPPEWA CO). TWIN SAULTS BOTH REPORTING OFF-AND-ON RAIN IN THE
PAST COUPLE OF HOURS. CLOUD COVER HAS DIMINISHED CONSIDERABLY IN
NORTHERN LOWER MI...WITH SOME PARTIAL CLEARING AS FAR NORTH AS WESTERN
MACKINAC. PRECIP FORECAST SEEMS TO BE IN GOOD SHAPE...WILL
CONTINUE TO BABYSIT CLOUD TRENDS AND ADJUST AS NEEDED.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

ELEVATED WARM FRONT/WARM AIR ADVECTION WING CONTINUES TO LIFT THRU
THE AREA TONIGHT WITH LINGERING MID LEVEL FGEN AND ADIABATIC OMEGA
POSSIBLY PRODUCING A FEW SPRINKLES/LIGHT SHOWER TIP OF THE MITT INTO
EASTERN UPPER.  SKY CONDITIONS RANGING FROM PARTLY CLOUDY SOUTH TO
MOSTLY CLOUDY NORTH.  A MILD NIGHT WITH LOWS FROM THE MID 40S TO
LOWER 50S.

BY FAR THE BEST DAY OF THE WEEKEND ON SUNDAY WITH 850MB THERMAL
RIDGE OF 13-15C BUILDING INTO THE AREA.  MID LEVEL RIDGING WILL
CONTINUE TO DOMINATE OUR WEATHER PICTURE AS DEEPER TROUGH DIGS INTO
THE NORTHERN PLAINS.  SFC DEWPOINTS WILL CONTINUE TO GRADUALLY CREEP
UP AS THE DAY PROGRESSES.  NAM CONTINUING ITS RECENT BIAS OF TOO WET
LOWER LEVELS...WITH CURRENT FCST DEWPOINTS 3-5 DEGF TOO HIGH BASED
ON LATEST OBSERVATIONS.  QUITE WARM ON SUNDAY...WITH HIGH TEMPS
REACHING THE MIDDLE 70S /EASTERN UPPER/ TO LOWER 80S /PORTIONS OF
NORTHERN LOWER/.  WEAK GRADIENT AND WARM TEMPS LEND ITSELF TO LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON HOURS AND WILL COOL TEMPS
CLOSER TO THE COASTS TO ACCOUNT FOR THIS.  EVEN WITH SLIGHTLY LOWER
DWPTS THAN THE NAM FCST SOUNDINGS...MODIFIED SOUNDINGS WITH NEAR DRY
ADIABATIC MIXED LAYER YIELD SEVERAL HUNDRED JOULES OF SKINNY CAPE.
INLAND PENETRATING LAKE BREEZE BOUNDARIES...INCREASING SFC DWPTS AND
SOME INSTABILITY SUPPORT ISOLATED SHOWER MENTION FOR INTERIOR AREAS
DURING THE MID/LATE AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

MID AND UPPER LEVEL PATTERN BECOMING INCREASINGLY BLOCKY WITH
TIME...AT LEAST PARTIALLY DRIVEN BY STRONG NORTH CENTRAL ATLANTIC
CENTERED HIGH PRESSURE RIDGE AXIS. DUAL STRONG SHORTWAVE TROUGHS
DIVING INTO THE PACIFIC NORTHWEST ONLY HELPING THE CAUSE...WITH LEAD
ENERGY EVENTUALLY CARVING OUT A SLOW MOVING UPPER LOW IN THE NATIONS
MIDSECTION EARLY NEXT WORK WEEK...WHILE THE NEXT PIECE DOES THE SAME
ACROSS THE PACIFIC NORTHWEST. SUBSEQUENT CANADIAN PRAIRIE RIDGE
BUILDING BETWEEN THESE FEATURES SETS UP A QUASI-OMEGA BLOCK
SIGNATURE...WITH STRONG ENERGY PROGGED TO DIVE DOWN ITS FRONTSIDE
INTO EAST CENTRAL CANADA ONLY ADDING FURTHER COMPLEXITY TO AN
ALREADY COMPLEX PATTERN. ADD IN A GOOD SUPPLY OF GULF OF MEXICO
MOISTURE AND FGEN DYNAMICS...AND THE PATTERN HAS ALL THE MAKINGS OF
A WET ONE THROUGH AT LEAST THE FIRST HALF OF THIS UPCOMING WEEK.
LATEST WPC 5 AND 7 DAY QUANTITATIVE PRECIPITATION FORECASTS
CONCUR...WITH WIDESPREAD 1 TO 2 INCH AMOUNTS ACROSS OUR AREA...WITH
HEAVIER AMOUNTS TO UPWARDS OF 4 INCHES JUST TO OUR NORTHWEST. AS ONE
CAN IMAGINE GIVEN ABOVE...EXTENDED FORECAST CONCERNS MAINLY CENTER
ON MULTI-PERIOD RAIN SHOWER AND THUNDERSTORM THREATS.

ONE COMPLICATED FORECAST SUNDAY NIGHT INTO MONDAY...WHICH...TO BE
HONEST...DOES NOT SUPPORT A WHOLE LOT OF FORECAST CONFIDENCE.
CENTRAL PLAINS CLOSED LOW BECOMES INCREASINGLY WELL ESTABLISHED...
WITH EXCELLENT FORCED LOW/MID LEVEL CONVERGENCE ZONE SETTING UP
BETWEEN SOUTH FLOW OUT AHEAD OF IT WEAK ENERGY DIVING THROUGH
ONTARIO. STRONG H8 CONVERGENCE AXIS LOOKS TO SLOWLY SAG SOUTH ACROSS
LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY...WITH SURFACE REFLECTION
ESSENTIALLY REMAINING STATIONARY ACROSS THE CLIMATOLOGICALLY FAVORED
TIP OF THE MITT/STRAITS REGION. H8 FRONT LOOKS TO REMAIN VERY
ACTIVE...FOCUSING MUCH OF THE RAIN OFF TO OUR NORTH THROUGH SUNDAY
NIGHT...PERHAPS INTO THE FIRST PART OF MONDAY (HELPED IN PART BY MID
LEVEL RIDGING REMAINING OVERHEAD). CONDITIONS BECOME MUCH MORE
INTERESTING HEADING INTO MONDAY AFTERNOON AND NIGHT AS ENERGY
ROTATING AROUND UPPER LEVEL LOW INTERACTS WITH AN INCREASINGLY
IMPRESSIVE OVERHEAD MOISTURE PLUME AS PWAT VALUES APPROACH AN INCH
AND A HALF. WHILE MODEL DEPICTED SURFACE DEWPOINTS IN THE UPPER
60S/LOWER 70S SEEM AGGRESSIVE...JUXTAPOSITION OF DECENT MOISTURE AND
MID LEVEL SUPPORT SHOULD BE ENOUGH TO KICK OFF ROUNDS OF SHOWERS AND
STORMS...SOME OF WHICH MAY BRING LOCALLY HEAVY RAINFALL. WHILE
SEVERE THREAT NOT COMPLETELY ZERO...BETTER POTENTIAL SHOULD REMAIN
TO OUR SOUTHWEST WITHIN CORRIDOR OF MUCH MORE IMPRESSIVE DEEP LAYER
SHEAR AND BETTER LOW LEVEL INSTABILITY. LATEST DAY 3 SPC SEVERE
GRAPHICS DOES BRING THE SLIGHT RISK RIGHT TO OUR DOORSTEP OVER
SOUTHWEST MICHIGAN. NO DOUBT WORTH KEEPING AN EYE ON THE NEXT FEW
DAYS AS UPSTREAM CONVECTIVE TRENDS WILL LIKELY PLAY HAVOC WITH EXACT
THERMODYNAMIC AND KINEMATIC DETAILS. POTENTIALLY ANOTHER WARM ONE
MONDAY...ESPECIALLY SOUTH OF THE BRIDGE. THERMAL PROGS EASILY
SUPPORT HIGHS BACK INTO THE LOWER 80S...ALTHOUGH CLOUD AND
CONVECTIVE TRENDS MAY PREVENT FULL WARMING FROM BEING REALIZED.

MID-WEEK WEATHER DEPENDENT ON INTERACTION (OR LACK THEREOF) BETWEEN
APPROACHING MID LEVEL LOW AND STRONGER ENERGY DIVING SOUTH OUT OF
CANADA. THE FORMER CONTINUES TO SUPPLY PLENTY OF MOISTURE AND
DYNAMICS...WHILE THE LATTER ATTEMPTS TO DRIVE BEST FGEN/BAROCLINIC
ZONE FURTHER SOUTH WITH TIME. DEEP LAYER CONVERGENCE AND MOISTURE
SUPPORTS PLENTY OF RAIN POTENTIAL...WITH PLACEMENT OF THE HEAVIEST
AND STEADIEST RAINFALL TIED TO ABOVE INTERACTION. 00Z ECMWF/GEM
OFFER A RATHER WET SCENARIO...KEEPING CORRIDOR OF DEEP LAYER
CONVERGENCE OVERHEAD RIGHT THROUGH THURSDAY. GFS A TOUCH MORE
AGGRESSIVE DRIVING THIS CORRIDOR SOUTH...ALTHOUGH IT TOO SUGGESTS
LINGERING RAINS INTO THURSDAY (JUST NOT AS HEAVY). HARD TO GET A
FEEL FOR WHICH IS MORE CORRECT...WITH THE END RESULT LIKELY A MIDDLE
GROUND BETWEEN THE TWO. INHERITED FORECAST KEEPS RAINS LINGERING
THROUGH THURSDAY...AS WILL THIS FORECAST. SEVERE THREAT SHOULD ONLY
SAG SOUTH WITH TIME AS LOW LEVEL BAROCLINIC ZONE DOES THE SAME. THAT
SAID...PROXIMITY OF IT AND SOME EVIDENCE FOR IT TO RETURN BRIEFLY
NORTH LATER WEDNESDAY...AS MAIN WESTERN ENERGY APPROACHES...
DEFINITELY RAISES SOME CONCERN.

START OF MEMORIAL DAY WEEKEND LOOKING COOL AND DRY AS CANADIAN HIGH
PRESSURE BUILDS OVERHEAD. HIGHS FRIDAY AND SATURDAY LOOK TO ONLY
REACH INTO 60S (UPPER 50S ACROSS EASTERN UPPER?)...WHICH WOULD BE AT
LEAST A FEW DEGREES BELOW NORMAL. PATTERN RECOGNITION SUPPORTS THE
POTENTIAL FOR SOME RATHER CHILLY OVERNIGHT READINGS THURSDAY THROUGH
SATURDAY. SOMEWHAT DISCONCERTING TO SEE LATEST CLIMO INFLUENCED
ECMWF MOS SHOWING COLDER LOCATIONS DIPPING INTO THE MIDDLE AND UPPER
30S EARLY FRIDAY MORNING...AND WIDESPREAD LOWER AND MIDDLE 30 DEGREE
READINGS SATURDAY MORNING. OTHER GUIDANCE NOT QUITE AS COLD...BUT
DEFINITELY SOMETHING TO MONITOR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1149 PM EDT SAT MAY 18 2013

VFR.

LIGHT SOUTHERLY FLOW IN PLACE IN THE LOW AND MID LEVELS...BETWEEN
HIGH PRESSURE OVER EASTERN CANADA...AND LOW PRESSURE IN THE CENTRAL/
SOUTHERN HIGH PLAINS. THIS WILL SLOWLY BRING MORE LOW-LEVEL MOISTURE
INTO THE REGION. WEAK DISTURBANCE PASSING ACROSS THE REGION
TONIGHT WILL BRING MID CLOUDS TO THE REGION...AND PERHAPS A
SPRINKLE NEAR PLN. ON SUNDAY...A MIX OF CUMULUS AND LINGERING MID
CLOUDS CAN BE EXPECTED. DEVELOPING LAKE BREEZES WILL LIKELY
TRIGGER A FEW SHRA IN THE AFTERNOON...BUT INLAND FROM ALL THE TAF
SITES.

LIGHT WINDS TONIGHT INTO SUNDAY MORNING...WITH ONSHORE WINDS
DEVELOPING EARLY SUNDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 316 PM EDT SAT MAY 18 2013

GRADIENT WILL REMAIN RELATIVELY WEAK OVER THE NEXT FEW DAYS AS HIGH
PRESSURE SLOWLY DEPARTS TO THE EAST. AS LOW PRESSURE DRAWS CLOSER
TO THE AREA TUESDAY/WEDNESDAY...WINDS WILL INCREASE AND SMALL
CRAFT CONDITIONS ARE POSSIBLE.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...MB
AVIATION...JZ
MARINE...JK

000
FXUS63 KDTX 190349
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1149 PM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

A REGION OF VERY DRY LOW LEVEL AIR CIRCULATING AROUND THE HIGH
PRESSURE SYSTEM TO THE EAST OF THE REGION HAS HELD SURFACE DEWPOINTS
IN THE 40S ACROSS MUCH OF THE AREA THIS EVENING. THE LOW LEVEL FLOW
WILL TURN MORE TOWARD THE SOUTHEAST DURING THE COURSE OF THE MORNING
WHICH WILL ADVECT THE MID TO UPPER 50S DEWPOINTS NOW OVER NORTH
CENTRAL OHIO INTO SE MI. IT NOW APPEARS THAT THE BULK OF THE SURFACE
MOISTURE ADVECTION WILL OCCUR AFTER DAYBREAK. THIS SUPPORTS THE
REMOVAL OF ANY MENTION OF HAZE IN THE TAFS. OTHERWISE...AN UPPER
LEVEL RIDGE WILL MAINTAIN BENIGN AVIATION WEATHER CONDITIONS THROUGH
THE AFTERNOON.

//DTW THRESHOLD THREATS...

* NONE

&&

.PREV DISCUSSION...ISSUED 338 PM EDT SAT MAY 18 2013

SHORT TERM...THIS EVENING AND TONIGHT

DOWNSTREAM AMPLIFICATION OF THE EASTERN NORTH AMERICA RIDGE WILL
OCCUR TONIGHT AS STRONG JET ENERGY DIGS THROUGH THE FOUR CORNERS.
THE MAIN CONSEQUENCE OF THIS DURING THE SHORT TERM IS THE APEX OF
THE RIDGE WILL SHARPEN AND LIFT INTO JAMES BAY GUIDING THE
CONSOLIDATED JET CORE ALONG WITH IT. THE NET RESULT IS FOR THE PESKY
ALTOSTRATUS THAT HAS BEEN HARBORED WITHIN THE SHEARING DEFORMATION
AXIS OVER NORTHERN LOWER MICHIGAN...SAGINAW BAY...THUMB TO EXIT WITH
TIME. MEANWHILE...WATER VAPOR IMAGERY SHOWS SMALLER WAVELENGTH
ANTICYCLONIC MOTION OVER PORTIONS OF NORTHEASTERN ILLINOIS AND LAKE
MICHIGAN FOLDING OVER. THIS HIGHLIGHTS THE INCREASING RIDGING ALOFT
THROUGH TONIGHT.

SOME MODIFICATION TO THE AIR MASS IN COMBINATION WITH A TREND VERY
LATE FOR SOME INCREASINGLY SOUTHERLY FLOW SUGGESTS A GOOD 2 TO 3
DEGREES WARMER TONIGHT. LOWS SHOULD DIP INTO THE LOWER 50S
NORTH...MIDDLE 50S SOUTH.

LONG TERM...SUNDAY THROUGH NEXT SATURDAY

UPPER RIDGE WILL HOLD OVER MICHIGAN FOR ONE MORE DAY TOMORROW.
SUBSIDENCE UNDER THE RIDGE SHOULD PREVENT SHOWERS/TSTORMS FROM
DEVELOPING...ALTHOUGH WE WILL BUILD UP SOME INSTABILITY DURING THE
DAY AS THE GROUND HEATS AND LAPSE RATES STEEPEN. SOUTHEAST WINDS
WILL REDUCE POTENTIAL FOR LOW-LEVEL CONVERGENCE NEAR THE LAKESHORES
(NO CONVECTIVE TRIGGER)...AND WILL ALSO HOLD TEMPERATURES CLOSER TO
THE SHORELINES INTO THE 70S. LOW 80S ARE EXPECTED WELL INLAND AS
GOOD INSOLATION COMBINES WITH RISING TEMPS AT 925-850MB. FRONTAL
BOUNDARY BY THIS POINT WILL ALSO BE POISED NORTH OF LAKE
HURON...HAVING LITTLE IMPACT ON WEATHER FOR SUNDAY BUT WILL BECOME A
FACTOR IN OUR WEATHER THROUGH MOST OF NEXT WEEK.

UPPER WAVE OFF THE PACIFIC NORTHWEST COAST WILL BECOME ABSORBED IN
THE BROAD UPPER TROUGH NOW ALONG AND WEST OF THE ROCKIES. MODELS
SHOW THIS SYSTEM CLOSING OFF OVER THE CENTRAL PLAINS ON
MONDAY...THEN VERY SLOWLY WORKING EAST INTO THE GREAT LAKES/OHIO
VALLEY BY THURSDAY. ARRIVAL OF THIS SYSTEM HAS BEEN HARD TO
PREDICT AS IT WILL EITHER CUT-OFF FROM MAIN FLOW OR REMAIN UNDER
VERY LIGHT STEERING FLOW. MODELS CONTINUE TO DISPLAY SOME TIMING
DIFFERENCES WITH ITS ENTRANCE AND EXIT INTO THE AREA...IN PART DUE
TO TIMING/PLACEMENT ISSUES WITH ANOTHER UPPER LOW DROPPING THROUGH
EASTERN CANADA. OVERALL CONFIDENCE IN THE FORECAST MONDAY AFTERNOON
THROUGH THURSDAY IS NOT HIGH...OTHER THAN TO SAY ROUNDS OF SHOWERS
AND THUNDERSTORMS WILL LIKELY ROLL THROUGH AND AFFECT EVERYTHING
FROM CLOUD COVER TO TEMPERATURES.

CHANCES FOR PRECIPITATION WILL START TO INCREASE LATE SUNDAY NIGHT
AND MONDAY MORNING AS A WEAK LOW-LEVEL JET NOSES TOWARDS LAKE
MICHIGAN. WEAK PUSH OF THETA-E ADVECTION COINCIDING WITH THIS COULD
TRIGGER A FEW SHOWERS/TSTORMS...AND HAVE MAINTAINED LOW POPS THROUGH
THE FIRST PART OF THE DAY ON MONDAY. MODELS THEN IN GREAT AGREEMENT
WITH CLIPPING SHORTWAVE ENERGY UP THROUGH LOWER MICHIGAN AS IT RIDES
SOUTHWEST FLOW PRECEDING THE LARGE LOW PRESSURE SYSTEM. MODEL TIMING
OF THIS WAVE VARIES FROM LATE MORNING THROUGH EARLY EVENING.
CONSENSUS DOES BRING IT THROUGH DURING THE LATE AFTERNOON...RIGHT AT
PEAK HEATING...AND WILL CONTINUE TO ANTICIPATE A FAIRLY GOOD
COVERAGE OF SHOWERS/TSTORMS DEVELOPING. CHANCES MAY BE BETTER
FURTHER NORTH OVER CENTRAL MICHIGAN...AS THE FRONTAL BOUNDARY NORTH
OF LAKE HURON STARTS TO DROP SOUTHWARD. THE FRONT WILL THEN BECOME
QUASI-STATIONARY OVER LOWER MICHIGAN (BEST SUPPORT FOR EITHER
CENTRAL OR NORTHERN LOWER) TUESDAY THROUGH EARLY WEDNESDAY...WHILE
ADDITIONAL UPPER SHORTWAVES EJECTING OUT OF THE LOW AND MCVS FROM
UPSTREAM CONVECTION RIDE OVER THE FRONT OR WITHIN THE WARM SECTOR
AND TRIGGER ADDITIONAL ROUNDS OF CONVECTION. THE FRONT SHOULD LIFT
BACK NORTH LATE ON WEDNESDAY AS THE LOW APPROACHES AND CROSSES THE
REGION...BEFORE DROPPING BACK SOUTH AS A STRONG COLD FRONT ON
THURSDAY.

TEMPERATURES WILL BE VERY UNCERTAIN WITH ROUNDS OF SHOWERS/TSTORMS
AND CLOUD REMNANTS FROM UPSTREAM CONVECTION CROSSING OVERHEAD.
ASSUMING A PRETTY DRY START TO THE DAY...TEMPERATURES ON MONDAY
SHOULD WARM INTO THE 80S. REMAINED A LITTLE CONSERVATIVE WITH
FORECAST HIGHS THE LOW/MID 80S. IF CONVECTION WAITS UNTIL VERY LATE
AFTERNOON OR EVENING TO FIRE...SOME LOCATIONS COULD SEE UPPER 80S.

SEVERE WEATHER MAY BECOME A CONCERN MONDAY THROUGH WEDNESDAY. MODEL
SB CAPE VALUES OF 2500-3000 J/KG MAY BE REALIZED ON MONDAY IN A
"FRESH ATMOSPHERE" THAT HAS NOT BEEN WORKED OVER...ASSUMING NO
UPSTREAM REMNANTS ARRIVE EARLY IN THE DAY. STRONGER STORMS MAY ALSO
FIRE OVERNIGHT AND ESPECIALLY TUESDAY AS THE FRONT LOOKS TO SINK
SLIGHTLY SOUTHWARD INTO THE AREA...AND UPPER JET SUPPORT BECOMES
MORE FAVORABLE. MODEL SB CAPE VALUES CONTINUE TO LOOK CONDUCIVE FOR
STRONG/SEVERE STORMS WEDNESDAY AS THE LOW APPROACHES AND THE FRONT
LIFTS BACK NORTH. SHEAR VALUES DO NOT LOOK OVERLY IMPRESSIVE ANY OF
THE DAYS HOWEVER. LOCALLY HEAVY RAINFALL WILL ALSO BE A THREAT WITH
PW VALUES RUNNING BETWEEN 1.25-1.50+ INCHES DURING THIS ENTIRE
TIMEFRAME.

QUIET WEATHER IS THEN EXPECTED TOWARDS THE END OF THE WEEK AS HIGH
PRESSURE BUILDS OVER THE AREA...BUT TEMPERATURES WILL RUN MUCH
COOLER WITH MAX TEMPS ONLY IN THE 60S.

MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
SHORT TERM...CB
LONG TERM....HLO
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 190349
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1149 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 316 PM EDT SAT MAY 18 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE
PLAINS...BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK.
THIS APPROACHING SYSTEM WILL GENERATE THUNDERSTORMS AND MILD
TEMPERATURES...OVER NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.UPDATE...
ISSUED AT 1013 PM EDT SAT MAY 18 2013

NEWBERRY AND THE SAULTS CONTINUE TO REPORT OCCASIONAL VERY LIGHT
PRECIP. THE RAIN GAGE AT THE SAULT MI ASOS HAS THUS FAR REFUSED TO
CLICK OFF EVEN 0.01 INCH. SO SPRINKLES MAY BE THE BEST
DESCRIPTOR...BUT WITH A CLUSTER OF SOMEWHAT STRONGER RETURNS JUST
WEST OF CHIP/MACK...HAVE MENTIONED SCT -SHRA UP UNTIL 07Z IN
EASTERN UPPER.

MID CLOUDS ARE MAKING A SE-WARD PUSH BACK INTO NORTHERN
LOWER...AND HAVE BECOME MORE WIDESPREAD NORTH OF A TVC-ROGERS
LINE. THE IDEA OF PARTLY CLOUDY SOUTH AND MOSTLY CLOUDY NORTH
STILL LOOKS SOUND...WITH SOME POTENTIAL FOR BUBBLY CU DEBRIS
DOWNSTATE TO BE DRAWN NORTHWARD INTO SOUTHERN SECTIONS OVERNIGHT.

ONLY MINOR TWEAKS TO MIN TEMPS.

UPDATE ISSUED AT 728 PM EDT SAT MAY 18 2013

VERY SPOTTY SPRINKLES/-SHRA RESTRICTED TO EASTERN UPPER MI (MAINLY
CHIPPEWA CO). TWIN SAULTS BOTH REPORTING OFF-AND-ON RAIN IN THE
PAST COUPLE OF HOURS. CLOUD COVER HAS DIMINISHED CONSIDERABLY IN
NORTHERN LOWER MI...WITH SOME PARTIAL CLEARING AS FAR NORTH AS WESTERN
MACKINAC. PRECIP FORECAST SEEMS TO BE IN GOOD SHAPE...WILL
CONTINUE TO BABYSIT CLOUD TRENDS AND ADJUST AS NEEDED.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

ELEVATED WARM FRONT/WARM AIR ADVECTION WING CONTINUES TO LIFT THRU
THE AREA TONIGHT WITH LINGERING MID LEVEL FGEN AND ADIABATIC OMEGA
POSSIBLY PRODUCING A FEW SPRINKLES/LIGHT SHOWER TIP OF THE MITT INTO
EASTERN UPPER.  SKY CONDITIONS RANGING FROM PARTLY CLOUDY SOUTH TO
MOSTLY CLOUDY NORTH.  A MILD NIGHT WITH LOWS FROM THE MID 40S TO
LOWER 50S.

BY FAR THE BEST DAY OF THE WEEKEND ON SUNDAY WITH 850MB THERMAL
RIDGE OF 13-15C BUILDING INTO THE AREA.  MID LEVEL RIDGING WILL
CONTINUE TO DOMINATE OUR WEATHER PICTURE AS DEEPER TROUGH DIGS INTO
THE NORTHERN PLAINS.  SFC DEWPOINTS WILL CONTINUE TO GRADUALLY CREEP
UP AS THE DAY PROGRESSES.  NAM CONTINUING ITS RECENT BIAS OF TOO WET
LOWER LEVELS...WITH CURRENT FCST DEWPOINTS 3-5 DEGF TOO HIGH BASED
ON LATEST OBSERVATIONS.  QUITE WARM ON SUNDAY...WITH HIGH TEMPS
REACHING THE MIDDLE 70S /EASTERN UPPER/ TO LOWER 80S /PORTIONS OF
NORTHERN LOWER/.  WEAK GRADIENT AND WARM TEMPS LEND ITSELF TO LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON HOURS AND WILL COOL TEMPS
CLOSER TO THE COASTS TO ACCOUNT FOR THIS.  EVEN WITH SLIGHTLY LOWER
DWPTS THAN THE NAM FCST SOUNDINGS...MODIFIED SOUNDINGS WITH NEAR DRY
ADIABATIC MIXED LAYER YIELD SEVERAL HUNDRED JOULES OF SKINNY CAPE.
INLAND PENETRATING LAKE BREEZE BOUNDARIES...INCREASING SFC DWPTS AND
SOME INSTABILITY SUPPORT ISOLATED SHOWER MENTION FOR INTERIOR AREAS
DURING THE MID/LATE AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

MID AND UPPER LEVEL PATTERN BECOMING INCREASINGLY BLOCKY WITH
TIME...AT LEAST PARTIALLY DRIVEN BY STRONG NORTH CENTRAL ATLANTIC
CENTERED HIGH PRESSURE RIDGE AXIS. DUAL STRONG SHORTWAVE TROUGHS
DIVING INTO THE PACIFIC NORTHWEST ONLY HELPING THE CAUSE...WITH LEAD
ENERGY EVENTUALLY CARVING OUT A SLOW MOVING UPPER LOW IN THE NATIONS
MIDSECTION EARLY NEXT WORK WEEK...WHILE THE NEXT PIECE DOES THE SAME
ACROSS THE PACIFIC NORTHWEST. SUBSEQUENT CANADIAN PRAIRIE RIDGE
BUILDING BETWEEN THESE FEATURES SETS UP A QUASI-OMEGA BLOCK
SIGNATURE...WITH STRONG ENERGY PROGGED TO DIVE DOWN ITS FRONTSIDE
INTO EAST CENTRAL CANADA ONLY ADDING FURTHER COMPLEXITY TO AN
ALREADY COMPLEX PATTERN. ADD IN A GOOD SUPPLY OF GULF OF MEXICO
MOISTURE AND FGEN DYNAMICS...AND THE PATTERN HAS ALL THE MAKINGS OF
A WET ONE THROUGH AT LEAST THE FIRST HALF OF THIS UPCOMING WEEK.
LATEST WPC 5 AND 7 DAY QUANTITATIVE PRECIPITATION FORECASTS
CONCUR...WITH WIDESPREAD 1 TO 2 INCH AMOUNTS ACROSS OUR AREA...WITH
HEAVIER AMOUNTS TO UPWARDS OF 4 INCHES JUST TO OUR NORTHWEST. AS ONE
CAN IMAGINE GIVEN ABOVE...EXTENDED FORECAST CONCERNS MAINLY CENTER
ON MULTI-PERIOD RAIN SHOWER AND THUNDERSTORM THREATS.

ONE COMPLICATED FORECAST SUNDAY NIGHT INTO MONDAY...WHICH...TO BE
HONEST...DOES NOT SUPPORT A WHOLE LOT OF FORECAST CONFIDENCE.
CENTRAL PLAINS CLOSED LOW BECOMES INCREASINGLY WELL ESTABLISHED...
WITH EXCELLENT FORCED LOW/MID LEVEL CONVERGENCE ZONE SETTING UP
BETWEEN SOUTH FLOW OUT AHEAD OF IT WEAK ENERGY DIVING THROUGH
ONTARIO. STRONG H8 CONVERGENCE AXIS LOOKS TO SLOWLY SAG SOUTH ACROSS
LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY...WITH SURFACE REFLECTION
ESSENTIALLY REMAINING STATIONARY ACROSS THE CLIMATOLOGICALLY FAVORED
TIP OF THE MITT/STRAITS REGION. H8 FRONT LOOKS TO REMAIN VERY
ACTIVE...FOCUSING MUCH OF THE RAIN OFF TO OUR NORTH THROUGH SUNDAY
NIGHT...PERHAPS INTO THE FIRST PART OF MONDAY (HELPED IN PART BY MID
LEVEL RIDGING REMAINING OVERHEAD). CONDITIONS BECOME MUCH MORE
INTERESTING HEADING INTO MONDAY AFTERNOON AND NIGHT AS ENERGY
ROTATING AROUND UPPER LEVEL LOW INTERACTS WITH AN INCREASINGLY
IMPRESSIVE OVERHEAD MOISTURE PLUME AS PWAT VALUES APPROACH AN INCH
AND A HALF. WHILE MODEL DEPICTED SURFACE DEWPOINTS IN THE UPPER
60S/LOWER 70S SEEM AGGRESSIVE...JUXTAPOSITION OF DECENT MOISTURE AND
MID LEVEL SUPPORT SHOULD BE ENOUGH TO KICK OFF ROUNDS OF SHOWERS AND
STORMS...SOME OF WHICH MAY BRING LOCALLY HEAVY RAINFALL. WHILE
SEVERE THREAT NOT COMPLETELY ZERO...BETTER POTENTIAL SHOULD REMAIN
TO OUR SOUTHWEST WITHIN CORRIDOR OF MUCH MORE IMPRESSIVE DEEP LAYER
SHEAR AND BETTER LOW LEVEL INSTABILITY. LATEST DAY 3 SPC SEVERE
GRAPHICS DOES BRING THE SLIGHT RISK RIGHT TO OUR DOORSTEP OVER
SOUTHWEST MICHIGAN. NO DOUBT WORTH KEEPING AN EYE ON THE NEXT FEW
DAYS AS UPSTREAM CONVECTIVE TRENDS WILL LIKELY PLAY HAVOC WITH EXACT
THERMODYNAMIC AND KINEMATIC DETAILS. POTENTIALLY ANOTHER WARM ONE
MONDAY...ESPECIALLY SOUTH OF THE BRIDGE. THERMAL PROGS EASILY
SUPPORT HIGHS BACK INTO THE LOWER 80S...ALTHOUGH CLOUD AND
CONVECTIVE TRENDS MAY PREVENT FULL WARMING FROM BEING REALIZED.

MID-WEEK WEATHER DEPENDENT ON INTERACTION (OR LACK THEREOF) BETWEEN
APPROACHING MID LEVEL LOW AND STRONGER ENERGY DIVING SOUTH OUT OF
CANADA. THE FORMER CONTINUES TO SUPPLY PLENTY OF MOISTURE AND
DYNAMICS...WHILE THE LATTER ATTEMPTS TO DRIVE BEST FGEN/BAROCLINIC
ZONE FURTHER SOUTH WITH TIME. DEEP LAYER CONVERGENCE AND MOISTURE
SUPPORTS PLENTY OF RAIN POTENTIAL...WITH PLACEMENT OF THE HEAVIEST
AND STEADIEST RAINFALL TIED TO ABOVE INTERACTION. 00Z ECMWF/GEM
OFFER A RATHER WET SCENARIO...KEEPING CORRIDOR OF DEEP LAYER
CONVERGENCE OVERHEAD RIGHT THROUGH THURSDAY. GFS A TOUCH MORE
AGGRESSIVE DRIVING THIS CORRIDOR SOUTH...ALTHOUGH IT TOO SUGGESTS
LINGERING RAINS INTO THURSDAY (JUST NOT AS HEAVY). HARD TO GET A
FEEL FOR WHICH IS MORE CORRECT...WITH THE END RESULT LIKELY A MIDDLE
GROUND BETWEEN THE TWO. INHERITED FORECAST KEEPS RAINS LINGERING
THROUGH THURSDAY...AS WILL THIS FORECAST. SEVERE THREAT SHOULD ONLY
SAG SOUTH WITH TIME AS LOW LEVEL BAROCLINIC ZONE DOES THE SAME. THAT
SAID...PROXIMITY OF IT AND SOME EVIDENCE FOR IT TO RETURN BRIEFLY
NORTH LATER WEDNESDAY...AS MAIN WESTERN ENERGY APPROACHES...
DEFINITELY RAISES SOME CONCERN.

START OF MEMORIAL DAY WEEKEND LOOKING COOL AND DRY AS CANADIAN HIGH
PRESSURE BUILDS OVERHEAD. HIGHS FRIDAY AND SATURDAY LOOK TO ONLY
REACH INTO 60S (UPPER 50S ACROSS EASTERN UPPER?)...WHICH WOULD BE AT
LEAST A FEW DEGREES BELOW NORMAL. PATTERN RECOGNITION SUPPORTS THE
POTENTIAL FOR SOME RATHER CHILLY OVERNIGHT READINGS THURSDAY THROUGH
SATURDAY. SOMEWHAT DISCONCERTING TO SEE LATEST CLIMO INFLUENCED
ECMWF MOS SHOWING COLDER LOCATIONS DIPPING INTO THE MIDDLE AND UPPER
30S EARLY FRIDAY MORNING...AND WIDESPREAD LOWER AND MIDDLE 30 DEGREE
READINGS SATURDAY MORNING. OTHER GUIDANCE NOT QUITE AS COLD...BUT
DEFINITELY SOMETHING TO MONITOR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1149 PM EDT SAT MAY 18 2013

VFR.

LIGHT SOUTHERLY FLOW IN PLACE IN THE LOW AND MID LEVELS...BETWEEN
HIGH PRESSURE OVER EASTERN CANADA...AND LOW PRESSURE IN THE CENTRAL/
SOUTHERN HIGH PLAINS. THIS WILL SLOWLY BRING MORE LOW-LEVEL MOISTURE
INTO THE REGION. WEAK DISTURBANCE PASSING ACROSS THE REGION
TONIGHT WILL BRING MID CLOUDS TO THE REGION...AND PERHAPS A
SPRINKLE NEAR PLN. ON SUNDAY...A MIX OF CUMULUS AND LINGERING MID
CLOUDS CAN BE EXPECTED. DEVELOPING LAKE BREEZES WILL LIKELY
TRIGGER A FEW SHRA IN THE AFTERNOON...BUT INLAND FROM ALL THE TAF
SITES.

LIGHT WINDS TONIGHT INTO SUNDAY MORNING...WITH ONSHORE WINDS
DEVELOPING EARLY SUNDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 316 PM EDT SAT MAY 18 2013

GRADIENT WILL REMAIN RELATIVELY WEAK OVER THE NEXT FEW DAYS AS HIGH
PRESSURE SLOWLY DEPARTS TO THE EAST. AS LOW PRESSURE DRAWS CLOSER
TO THE AREA TUESDAY/WEDNESDAY...WINDS WILL INCREASE AND SMALL
CRAFT CONDITIONS ARE POSSIBLE.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...MB
AVIATION...JZ
MARINE...JK

000
FXUS63 KDTX 190349
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1149 PM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

A REGION OF VERY DRY LOW LEVEL AIR CIRCULATING AROUND THE HIGH
PRESSURE SYSTEM TO THE EAST OF THE REGION HAS HELD SURFACE DEWPOINTS
IN THE 40S ACROSS MUCH OF THE AREA THIS EVENING. THE LOW LEVEL FLOW
WILL TURN MORE TOWARD THE SOUTHEAST DURING THE COURSE OF THE MORNING
WHICH WILL ADVECT THE MID TO UPPER 50S DEWPOINTS NOW OVER NORTH
CENTRAL OHIO INTO SE MI. IT NOW APPEARS THAT THE BULK OF THE SURFACE
MOISTURE ADVECTION WILL OCCUR AFTER DAYBREAK. THIS SUPPORTS THE
REMOVAL OF ANY MENTION OF HAZE IN THE TAFS. OTHERWISE...AN UPPER
LEVEL RIDGE WILL MAINTAIN BENIGN AVIATION WEATHER CONDITIONS THROUGH
THE AFTERNOON.

//DTW THRESHOLD THREATS...

* NONE

&&

.PREV DISCUSSION...ISSUED 338 PM EDT SAT MAY 18 2013

SHORT TERM...THIS EVENING AND TONIGHT

DOWNSTREAM AMPLIFICATION OF THE EASTERN NORTH AMERICA RIDGE WILL
OCCUR TONIGHT AS STRONG JET ENERGY DIGS THROUGH THE FOUR CORNERS.
THE MAIN CONSEQUENCE OF THIS DURING THE SHORT TERM IS THE APEX OF
THE RIDGE WILL SHARPEN AND LIFT INTO JAMES BAY GUIDING THE
CONSOLIDATED JET CORE ALONG WITH IT. THE NET RESULT IS FOR THE PESKY
ALTOSTRATUS THAT HAS BEEN HARBORED WITHIN THE SHEARING DEFORMATION
AXIS OVER NORTHERN LOWER MICHIGAN...SAGINAW BAY...THUMB TO EXIT WITH
TIME. MEANWHILE...WATER VAPOR IMAGERY SHOWS SMALLER WAVELENGTH
ANTICYCLONIC MOTION OVER PORTIONS OF NORTHEASTERN ILLINOIS AND LAKE
MICHIGAN FOLDING OVER. THIS HIGHLIGHTS THE INCREASING RIDGING ALOFT
THROUGH TONIGHT.

SOME MODIFICATION TO THE AIR MASS IN COMBINATION WITH A TREND VERY
LATE FOR SOME INCREASINGLY SOUTHERLY FLOW SUGGESTS A GOOD 2 TO 3
DEGREES WARMER TONIGHT. LOWS SHOULD DIP INTO THE LOWER 50S
NORTH...MIDDLE 50S SOUTH.

LONG TERM...SUNDAY THROUGH NEXT SATURDAY

UPPER RIDGE WILL HOLD OVER MICHIGAN FOR ONE MORE DAY TOMORROW.
SUBSIDENCE UNDER THE RIDGE SHOULD PREVENT SHOWERS/TSTORMS FROM
DEVELOPING...ALTHOUGH WE WILL BUILD UP SOME INSTABILITY DURING THE
DAY AS THE GROUND HEATS AND LAPSE RATES STEEPEN. SOUTHEAST WINDS
WILL REDUCE POTENTIAL FOR LOW-LEVEL CONVERGENCE NEAR THE LAKESHORES
(NO CONVECTIVE TRIGGER)...AND WILL ALSO HOLD TEMPERATURES CLOSER TO
THE SHORELINES INTO THE 70S. LOW 80S ARE EXPECTED WELL INLAND AS
GOOD INSOLATION COMBINES WITH RISING TEMPS AT 925-850MB. FRONTAL
BOUNDARY BY THIS POINT WILL ALSO BE POISED NORTH OF LAKE
HURON...HAVING LITTLE IMPACT ON WEATHER FOR SUNDAY BUT WILL BECOME A
FACTOR IN OUR WEATHER THROUGH MOST OF NEXT WEEK.

UPPER WAVE OFF THE PACIFIC NORTHWEST COAST WILL BECOME ABSORBED IN
THE BROAD UPPER TROUGH NOW ALONG AND WEST OF THE ROCKIES. MODELS
SHOW THIS SYSTEM CLOSING OFF OVER THE CENTRAL PLAINS ON
MONDAY...THEN VERY SLOWLY WORKING EAST INTO THE GREAT LAKES/OHIO
VALLEY BY THURSDAY. ARRIVAL OF THIS SYSTEM HAS BEEN HARD TO
PREDICT AS IT WILL EITHER CUT-OFF FROM MAIN FLOW OR REMAIN UNDER
VERY LIGHT STEERING FLOW. MODELS CONTINUE TO DISPLAY SOME TIMING
DIFFERENCES WITH ITS ENTRANCE AND EXIT INTO THE AREA...IN PART DUE
TO TIMING/PLACEMENT ISSUES WITH ANOTHER UPPER LOW DROPPING THROUGH
EASTERN CANADA. OVERALL CONFIDENCE IN THE FORECAST MONDAY AFTERNOON
THROUGH THURSDAY IS NOT HIGH...OTHER THAN TO SAY ROUNDS OF SHOWERS
AND THUNDERSTORMS WILL LIKELY ROLL THROUGH AND AFFECT EVERYTHING
FROM CLOUD COVER TO TEMPERATURES.

CHANCES FOR PRECIPITATION WILL START TO INCREASE LATE SUNDAY NIGHT
AND MONDAY MORNING AS A WEAK LOW-LEVEL JET NOSES TOWARDS LAKE
MICHIGAN. WEAK PUSH OF THETA-E ADVECTION COINCIDING WITH THIS COULD
TRIGGER A FEW SHOWERS/TSTORMS...AND HAVE MAINTAINED LOW POPS THROUGH
THE FIRST PART OF THE DAY ON MONDAY. MODELS THEN IN GREAT AGREEMENT
WITH CLIPPING SHORTWAVE ENERGY UP THROUGH LOWER MICHIGAN AS IT RIDES
SOUTHWEST FLOW PRECEDING THE LARGE LOW PRESSURE SYSTEM. MODEL TIMING
OF THIS WAVE VARIES FROM LATE MORNING THROUGH EARLY EVENING.
CONSENSUS DOES BRING IT THROUGH DURING THE LATE AFTERNOON...RIGHT AT
PEAK HEATING...AND WILL CONTINUE TO ANTICIPATE A FAIRLY GOOD
COVERAGE OF SHOWERS/TSTORMS DEVELOPING. CHANCES MAY BE BETTER
FURTHER NORTH OVER CENTRAL MICHIGAN...AS THE FRONTAL BOUNDARY NORTH
OF LAKE HURON STARTS TO DROP SOUTHWARD. THE FRONT WILL THEN BECOME
QUASI-STATIONARY OVER LOWER MICHIGAN (BEST SUPPORT FOR EITHER
CENTRAL OR NORTHERN LOWER) TUESDAY THROUGH EARLY WEDNESDAY...WHILE
ADDITIONAL UPPER SHORTWAVES EJECTING OUT OF THE LOW AND MCVS FROM
UPSTREAM CONVECTION RIDE OVER THE FRONT OR WITHIN THE WARM SECTOR
AND TRIGGER ADDITIONAL ROUNDS OF CONVECTION. THE FRONT SHOULD LIFT
BACK NORTH LATE ON WEDNESDAY AS THE LOW APPROACHES AND CROSSES THE
REGION...BEFORE DROPPING BACK SOUTH AS A STRONG COLD FRONT ON
THURSDAY.

TEMPERATURES WILL BE VERY UNCERTAIN WITH ROUNDS OF SHOWERS/TSTORMS
AND CLOUD REMNANTS FROM UPSTREAM CONVECTION CROSSING OVERHEAD.
ASSUMING A PRETTY DRY START TO THE DAY...TEMPERATURES ON MONDAY
SHOULD WARM INTO THE 80S. REMAINED A LITTLE CONSERVATIVE WITH
FORECAST HIGHS THE LOW/MID 80S. IF CONVECTION WAITS UNTIL VERY LATE
AFTERNOON OR EVENING TO FIRE...SOME LOCATIONS COULD SEE UPPER 80S.

SEVERE WEATHER MAY BECOME A CONCERN MONDAY THROUGH WEDNESDAY. MODEL
SB CAPE VALUES OF 2500-3000 J/KG MAY BE REALIZED ON MONDAY IN A
"FRESH ATMOSPHERE" THAT HAS NOT BEEN WORKED OVER...ASSUMING NO
UPSTREAM REMNANTS ARRIVE EARLY IN THE DAY. STRONGER STORMS MAY ALSO
FIRE OVERNIGHT AND ESPECIALLY TUESDAY AS THE FRONT LOOKS TO SINK
SLIGHTLY SOUTHWARD INTO THE AREA...AND UPPER JET SUPPORT BECOMES
MORE FAVORABLE. MODEL SB CAPE VALUES CONTINUE TO LOOK CONDUCIVE FOR
STRONG/SEVERE STORMS WEDNESDAY AS THE LOW APPROACHES AND THE FRONT
LIFTS BACK NORTH. SHEAR VALUES DO NOT LOOK OVERLY IMPRESSIVE ANY OF
THE DAYS HOWEVER. LOCALLY HEAVY RAINFALL WILL ALSO BE A THREAT WITH
PW VALUES RUNNING BETWEEN 1.25-1.50+ INCHES DURING THIS ENTIRE
TIMEFRAME.

QUIET WEATHER IS THEN EXPECTED TOWARDS THE END OF THE WEEK AS HIGH
PRESSURE BUILDS OVER THE AREA...BUT TEMPERATURES WILL RUN MUCH
COOLER WITH MAX TEMPS ONLY IN THE 60S.

MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
SHORT TERM...CB
LONG TERM....HLO
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 190213
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1013 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 316 PM EDT SAT MAY 18 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE
PLAINS...BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK.
THIS APPROACHING SYSTEM WILL GENERATE THUNDERSTORMS AND MILD
TEMPERATURES...OVER NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.UPDATE...
ISSUED AT 1013 PM EDT SAT MAY 18 2013

NEWBERRY AND THE SAULTS CONTINUE TO REPORT OCCASIONAL VERY LIGHT
PRECIP. THE RAIN GAGE AT THE SAULT MI ASOS HAS THUS FAR REFUSED TO
CLICK OFF EVEN 0.01 INCH. SO SPRINKLES MAY BE THE BEST
DESCRIPTOR...BUT WITH A CLUSTER OF SOMEWHAT STRONGER RETURNS JUST
WEST OF CHIP/MACK...HAVE MENTIONED SCT -SHRA UP UNTIL 07Z IN
EASTERN UPPER.

MID CLOUDS ARE MAKING A SE-WARD PUSH BACK INTO NORTHERN
LOWER...AND HAVE BECOME MORE WIDESPREAD NORTH OF A TVC-ROGERS
LINE. THE IDEA OF PARTLY CLOUDY SOUTH AND MOSTLY CLOUDY NORTH
STILL LOOKS SOUND...WITH SOME POTENTIAL FOR BUBBLY CU DEBRIS
DOWNSTATE TO BE DRAWN NORTHWARD INTO SOUTHERN SECTIONS OVERNIGHT.

ONLY MINOR TWEAKS TO MIN TEMPS.

UPDATE ISSUED AT 728 PM EDT SAT MAY 18 2013

VERY SPOTTY SPRINKLES/-SHRA RESTRICTED TO EASTERN UPPER MI (MAINLY
CHIPPEWA CO). TWIN SAULTS BOTH REPORTING OFF-AND-ON RAIN IN THE
PAST COUPLE OF HOURS. CLOUD COVER HAS DIMINISHED CONSIDERABLY IN
NORTHERN LOWER MI...WITH SOME PARTIAL CLEARING AS FAR NORTH AS WESTERN
MACKINAC. PRECIP FORECAST SEEMS TO BE IN GOOD SHAPE...WILL
CONTINUE TO BABYSIT CLOUD TRENDS AND ADJUST AS NEEDED.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

ELEVATED WARM FRONT/WARM AIR ADVECTION WING CONTINUES TO LIFT THRU
THE AREA TONIGHT WITH LINGERING MID LEVEL FGEN AND ADIABATIC OMEGA
POSSIBLY PRODUCING A FEW SPRINKLES/LIGHT SHOWER TIP OF THE MITT INTO
EASTERN UPPER.  SKY CONDITIONS RANGING FROM PARTLY CLOUDY SOUTH TO
MOSTLY CLOUDY NORTH.  A MILD NIGHT WITH LOWS FROM THE MID 40S TO
LOWER 50S.

BY FAR THE BEST DAY OF THE WEEKEND ON SUNDAY WITH 850MB THERMAL
RIDGE OF 13-15C BUILDING INTO THE AREA.  MID LEVEL RIDGING WILL
CONTINUE TO DOMINATE OUR WEATHER PICTURE AS DEEPER TROUGH DIGS INTO
THE NORTHERN PLAINS.  SFC DEWPOINTS WILL CONTINUE TO GRADUALLY CREEP
UP AS THE DAY PROGRESSES.  NAM CONTINUING ITS RECENT BIAS OF TOO WET
LOWER LEVELS...WITH CURRENT FCST DEWPOINTS 3-5 DEGF TOO HIGH BASED
ON LATEST OBSERVATIONS.  QUITE WARM ON SUNDAY...WITH HIGH TEMPS
REACHING THE MIDDLE 70S /EASTERN UPPER/ TO LOWER 80S /PORTIONS OF
NORTHERN LOWER/.  WEAK GRADIENT AND WARM TEMPS LEND ITSELF TO LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON HOURS AND WILL COOL TEMPS
CLOSER TO THE COASTS TO ACCOUNT FOR THIS.  EVEN WITH SLIGHTLY LOWER
DWPTS THAN THE NAM FCST SOUNDINGS...MODIFIED SOUNDINGS WITH NEAR DRY
ADIABATIC MIXED LAYER YIELD SEVERAL HUNDRED JOULES OF SKINNY CAPE.
INLAND PENETRATING LAKE BREEZE BOUNDARIES...INCREASING SFC DWPTS AND
SOME INSTABILITY SUPPORT ISOLATED SHOWER MENTION FOR INTERIOR AREAS
DURING THE MID/LATE AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

MID AND UPPER LEVEL PATTERN BECOMING INCREASINGLY BLOCKY WITH
TIME...AT LEAST PARTIALLY DRIVEN BY STRONG NORTH CENTRAL ATLANTIC
CENTERED HIGH PRESSURE RIDGE AXIS. DUAL STRONG SHORTWAVE TROUGHS
DIVING INTO THE PACIFIC NORTHWEST ONLY HELPING THE CAUSE...WITH LEAD
ENERGY EVENTUALLY CARVING OUT A SLOW MOVING UPPER LOW IN THE NATIONS
MIDSECTION EARLY NEXT WORK WEEK...WHILE THE NEXT PIECE DOES THE SAME
ACROSS THE PACIFIC NORTHWEST. SUBSEQUENT CANADIAN PRAIRIE RIDGE
BUILDING BETWEEN THESE FEATURES SETS UP A QUASI-OMEGA BLOCK
SIGNATURE...WITH STRONG ENERGY PROGGED TO DIVE DOWN ITS FRONTSIDE
INTO EAST CENTRAL CANADA ONLY ADDING FURTHER COMPLEXITY TO AN
ALREADY COMPLEX PATTERN. ADD IN A GOOD SUPPLY OF GULF OF MEXICO
MOISTURE AND FGEN DYNAMICS...AND THE PATTERN HAS ALL THE MAKINGS OF
A WET ONE THROUGH AT LEAST THE FIRST HALF OF THIS UPCOMING WEEK.
LATEST WPC 5 AND 7 DAY QUANTITATIVE PRECIPITATION FORECASTS
CONCUR...WITH WIDESPREAD 1 TO 2 INCH AMOUNTS ACROSS OUR AREA...WITH
HEAVIER AMOUNTS TO UPWARDS OF 4 INCHES JUST TO OUR NORTHWEST. AS ONE
CAN IMAGINE GIVEN ABOVE...EXTENDED FORECAST CONCERNS MAINLY CENTER
ON MULTI-PERIOD RAIN SHOWER AND THUNDERSTORM THREATS.

ONE COMPLICATED FORECAST SUNDAY NIGHT INTO MONDAY...WHICH...TO BE
HONEST...DOES NOT SUPPORT A WHOLE LOT OF FORECAST CONFIDENCE.
CENTRAL PLAINS CLOSED LOW BECOMES INCREASINGLY WELL ESTABLISHED...
WITH EXCELLENT FORCED LOW/MID LEVEL CONVERGENCE ZONE SETTING UP
BETWEEN SOUTH FLOW OUT AHEAD OF IT WEAK ENERGY DIVING THROUGH
ONTARIO. STRONG H8 CONVERGENCE AXIS LOOKS TO SLOWLY SAG SOUTH ACROSS
LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY...WITH SURFACE REFLECTION
ESSENTIALLY REMAINING STATIONARY ACROSS THE CLIMATOLOGICALLY FAVORED
TIP OF THE MITT/STRAITS REGION. H8 FRONT LOOKS TO REMAIN VERY
ACTIVE...FOCUSING MUCH OF THE RAIN OFF TO OUR NORTH THROUGH SUNDAY
NIGHT...PERHAPS INTO THE FIRST PART OF MONDAY (HELPED IN PART BY MID
LEVEL RIDGING REMAINING OVERHEAD). CONDITIONS BECOME MUCH MORE
INTERESTING HEADING INTO MONDAY AFTERNOON AND NIGHT AS ENERGY
ROTATING AROUND UPPER LEVEL LOW INTERACTS WITH AN INCREASINGLY
IMPRESSIVE OVERHEAD MOISTURE PLUME AS PWAT VALUES APPROACH AN INCH
AND A HALF. WHILE MODEL DEPICTED SURFACE DEWPOINTS IN THE UPPER
60S/LOWER 70S SEEM AGGRESSIVE...JUXTAPOSITION OF DECENT MOISTURE AND
MID LEVEL SUPPORT SHOULD BE ENOUGH TO KICK OFF ROUNDS OF SHOWERS AND
STORMS...SOME OF WHICH MAY BRING LOCALLY HEAVY RAINFALL. WHILE
SEVERE THREAT NOT COMPLETELY ZERO...BETTER POTENTIAL SHOULD REMAIN
TO OUR SOUTHWEST WITHIN CORRIDOR OF MUCH MORE IMPRESSIVE DEEP LAYER
SHEAR AND BETTER LOW LEVEL INSTABILITY. LATEST DAY 3 SPC SEVERE
GRAPHICS DOES BRING THE SLIGHT RISK RIGHT TO OUR DOORSTEP OVER
SOUTHWEST MICHIGAN. NO DOUBT WORTH KEEPING AN EYE ON THE NEXT FEW
DAYS AS UPSTREAM CONVECTIVE TRENDS WILL LIKELY PLAY HAVOC WITH EXACT
THERMODYNAMIC AND KINEMATIC DETAILS. POTENTIALLY ANOTHER WARM ONE
MONDAY...ESPECIALLY SOUTH OF THE BRIDGE. THERMAL PROGS EASILY
SUPPORT HIGHS BACK INTO THE LOWER 80S...ALTHOUGH CLOUD AND
CONVECTIVE TRENDS MAY PREVENT FULL WARMING FROM BEING REALIZED.

MID-WEEK WEATHER DEPENDENT ON INTERACTION (OR LACK THEREOF) BETWEEN
APPROACHING MID LEVEL LOW AND STRONGER ENERGY DIVING SOUTH OUT OF
CANADA. THE FORMER CONTINUES TO SUPPLY PLENTY OF MOISTURE AND
DYNAMICS...WHILE THE LATTER ATTEMPTS TO DRIVE BEST FGEN/BAROCLINIC
ZONE FURTHER SOUTH WITH TIME. DEEP LAYER CONVERGENCE AND MOISTURE
SUPPORTS PLENTY OF RAIN POTENTIAL...WITH PLACEMENT OF THE HEAVIEST
AND STEADIEST RAINFALL TIED TO ABOVE INTERACTION. 00Z ECMWF/GEM
OFFER A RATHER WET SCENARIO...KEEPING CORRIDOR OF DEEP LAYER
CONVERGENCE OVERHEAD RIGHT THROUGH THURSDAY. GFS A TOUCH MORE
AGGRESSIVE DRIVING THIS CORRIDOR SOUTH...ALTHOUGH IT TOO SUGGESTS
LINGERING RAINS INTO THURSDAY (JUST NOT AS HEAVY). HARD TO GET A
FEEL FOR WHICH IS MORE CORRECT...WITH THE END RESULT LIKELY A MIDDLE
GROUND BETWEEN THE TWO. INHERITED FORECAST KEEPS RAINS LINGERING
THROUGH THURSDAY...AS WILL THIS FORECAST. SEVERE THREAT SHOULD ONLY
SAG SOUTH WITH TIME AS LOW LEVEL BAROCLINIC ZONE DOES THE SAME. THAT
SAID...PROXIMITY OF IT AND SOME EVIDENCE FOR IT TO RETURN BRIEFLY
NORTH LATER WEDNESDAY...AS MAIN WESTERN ENERGY APPROACHES...
DEFINITELY RAISES SOME CONCERN.

START OF MEMORIAL DAY WEEKEND LOOKING COOL AND DRY AS CANADIAN HIGH
PRESSURE BUILDS OVERHEAD. HIGHS FRIDAY AND SATURDAY LOOK TO ONLY
REACH INTO 60S (UPPER 50S ACROSS EASTERN UPPER?)...WHICH WOULD BE AT
LEAST A FEW DEGREES BELOW NORMAL. PATTERN RECOGNITION SUPPORTS THE
POTENTIAL FOR SOME RATHER CHILLY OVERNIGHT READINGS THURSDAY THROUGH
SATURDAY. SOMEWHAT DISCONCERTING TO SEE LATEST CLIMO INFLUENCED
ECMWF MOS SHOWING COLDER LOCATIONS DIPPING INTO THE MIDDLE AND UPPER
30S EARLY FRIDAY MORNING...AND WIDESPREAD LOWER AND MIDDLE 30 DEGREE
READINGS SATURDAY MORNING. OTHER GUIDANCE NOT QUITE AS COLD...BUT
DEFINITELY SOMETHING TO MONITOR.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 728 PM EDT SAT MAY 18 2013

VFR.

LIGHT SOUTHERLY FLOW IN PLACE IN THE LOW AND MID LEVELS...BETWEEN
HIGH PRESSURE OVER EASTERN CANADA...AND LOW PRESSURE IN THE CENTRAL/
SOUTHERN HIGH PLAINS. THIS WILL SLOWLY BRING MORE LOW-LEVEL MOISTURE
INTO THE REGION. INITIALLY...BAND OF MID/HIGH CLOUDS WILL CONTINUE
TO LIFT NORTH OUT OF NORTHERN LOWER TONIGHT. PATCHY MID CLOUDS
WILL RETURN TO NORTHERN LOWER OVERNIGHT FROM THE SOUTH. SUNDAY
WILL BE SUNNIER...WARMER...AND SOMEWHAT MORE HUMID. DEVELOPING LAKE
BREEZES WILL LIKELY TRIGGER A FEW SHRA IN THE AFTERNOON...BUT
INLAND FROM ALL THE TAF SITES.

LIGHT WINDS TONIGHT INTO SUNDAY MORNING...WITH ONSHORE WINDS
DEVELOPING EARLY SUNDAY AFTERNOON.


&&

.MARINE...
ISSUED AT 316 PM EDT SAT MAY 18 2013

GRADIENT WILL REMAIN RELATIVELY WEAK OVER THE NEXT FEW DAYS AS HIGH
PRESSURE SLOWLY DEPARTS TO THE EAST. AS LOW PRESSURE DRAWS CLOSER
TO THE AREA TUESDAY/WEDNESDAY...WINDS WILL INCREASE AND SMALL
CRAFT CONDITIONS ARE POSSIBLE.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...MB
AVIATION...JZ
MARINE...JK

000
FXUS63 KMQT 190007
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
807 PM EDT SAT MAY 18 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

PRECIP OVER THE NRN HALF OF THE CWA THIS AFTERNOON IS BEING DRIVEN
BY MOISTURE TRANSPORT/WAA BEHIND AN 850MB WARM FRONT THAT IS
APPROACHING NERN LAKE SUPERIOR. SLY FLOW BEHIND THE FRONT BETWEEN
DEVELOPING LOW PRESSURE OVER THE PLAINS AND HIGH PRESSURE OVER
QUEBEC WILL CONTINUE TO STREAM WARMER TEMPS AND MOISTURE INTO THE
CWA TONIGHT...WHILE THE 850MB WARM FRONT STALLS OUT OVER THE NRN
CWA. THE FRONT STAYING OVER THE NRN CWA INTO TONIGHT WILL KEEP
PRECIP CHANCES HIGHEST OVER THE KEWEENAW PENINSULA...WITH LITTLE TO
NO PRECIP EXPECTED ELSEWHERE.

WITH 850MB TEMPS AROUND 14C SUN...AND LESS LOW LEVEL MOISTURE THAN
THE GFS/NAM SHOW AS HAS BEEN THE CASE LATELY...EXPECT HIGH TEMPS
AROUND 80 AWAY FROM MODERATING LAKE SUPERIOR. THE SYSTEM OVER THE
PLAINS WILL WRAP UP OVER SD BY 00Z MON WHILE SFC HIGH PRESSURE MOVES
FROM THE NRN TERRITORIES OF CANADA NOW TO NRN ONTARIO BY 00Z MON.
WITH THE SFC HIGH SLIDING TOWARD THE AREA BEHIND AN UPPER TROUGH AND
THE LOW CLOSING OFF TO THE W...EXPECT A SFC TROUGH TO SLIDE INTO THE
CWA LATER SUN. THIS WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS
TO MOVE BACK INTO THE WRN HALF OF THE CWA BY LATE SUN. FOR THE MOST
PART...GENERAL THUNDER IS EXPECT...BUT CAN NOT COMPLETELY RULE OUT A
STRONGER STORM OR TWO ALONG THE WI BORDER WITH 500-1000J/KG OF CAPE
AND AROUND 30KTS OF 0-6KM BULK SHEAR ALONG THE SRN CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

SUNDAY NIGHT...ALTHOUGH THERE WERE SOME DIFFERENCES...THE MODELS
WERE IN GENERAL AGREEMENT WITH THE POSITION OF THE MID LEVEL LOW
MOVING INTO CNTRL NEBRASKA AND THE SFC LOW TO SE SD BY 12Z MON. THE
SFC WARM FRONT WILL STRENGTHEN ACROSS SRN MN INTO SRN WI. EXPECT THAT
PCPN WILL INCREASE/EXPAND ACROSS THE WEST/CNTRL CWA WITH MOISTURE
INFLOW AND 300K-310K ISENTROPIC ASCENT ALONG THE 850-700 MB FRONT.
ALTHOUGH THE GREATEST INSTABILITY TO SUPPORT TSRA WILL REMAIN TO THE
SOUTH...SOME EMBEDDED ELEVATED CONVECTION WILL BE POSSIBLE.

MON INTO MON NIGHT...AS THE MID LEVEL LOW REMAINS NEARLY STATIONARY
OR MOVES SLIGHTLY TO THE EAST AND UPPER LEVEL DIV/700-300 MB QVECTOR
CONV FORCING FOR LARGE SCALE ASCENT REMAINS OVER THE AREA...SMALLER
SCALE SHORTWAVES MOVING THROUGH THE AREA WILL SUPPORT PERIODS OF RAIN
SHOWERS. HEAVY RAINFALL AMOUNTS OF 1 TO 2 INCHES REMAIN POSSIBLE WITH
ABUNDANT MOISTURE AVAILABLE (PWAT VALUES TO AROUND 1.5 INCHES...200
PERCENT OF NORMAL). ELEVATED TSRA CHANCES ALSO CONTINUE WITH MUCAPE
VALUES IN THE 500-1000 J/KG. CLOUD COVER AND PCPN WILL KEEP TEMPS
MAINLY TOWARD THE LOWER END OF GUIDANCE...ESPECIALLY DOWNWIND FROM
ERLY FLOW OFF OF THE GREAT LAKES.

TUE-WED...MODELS SUGGEST THAT THE BLOCKING/STAGNANT PATTERN WITH A
PROMINENT RIDGE OVER S CNTRL CANADA WILL FAVOR CONTINUED SLOW
PROGRESSION OF THE MID LEVEL LOW TO THE NE TO AROUND SE MN OR WRN WI
BY 00Z THU. SO...LIKELY OR HIGHER END CHANCE PCPN POPS WILL
CONTINUE. PCPN...THICKER CLOUDS AND PCPN WILL KEEP TEMPS BELOW
NORMAL.

THU-SAT...ALTHOUGH THE 00Z/12Z ECMWF WAS THE MOST AGGRESSIVE IN
BRINGING THE AREA UNDER THE INFLUENCE OF NW FLOW DOWNSTREAM FROM THE
BLOCKING RIDGE...THE GFS AND GFS ENSEMBLES ALSO HAVE TRENDED TOWARD
THAT SCENARIO. THIS WOULD FINALLY BRING DRIER AND COOL AIR INTO THE
REGION WITH TEMPS REMAINING BELOW NORMAL AS HIGH PRES BUILDS INTO THE
NRN GREAT LAKES FROM NRN ONTARIO.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 806 PM EDT SAT MAY 18 2013

CHALLENGING FCST SHAPING UP THRU THIS FCST PERIOD...ESPECIALLY AT
KCMX. AT KIWD/KSAW...OPTED FOR VFR CONDITIONS THRU THE PERIOD THOUGH
MAY SEE MVFR POSSIBLE IFR IF ANY SHRA OCCUR TONIGHT. LOWER
CONDITIONS COULD ALSO OCCUR AT KSAW LATE TONIGHT DUE TO UPSLOPE
SOUTHERLY FLOW. SINCE POTENTIAL FOR SHRA IS VERY UNCERTAIN...DID NOT
INCLUDE ANY MENTION UNTIL LATER SUN WHEN COLD FRONT SAGS S INTO
UPPER MI. AT KCMX...MOIST UPSLOPE EASTERLY FLOW OFF LAKE SUPERIOR
WILL PROBABLY RESULT IN MVFR/OCNL IFR FALLING TO LIFR BY LATE
EVENING...AND THAT COULD OCCUR EARLIER THAN FCST. LATER IN THE
NIGHT...IT APPEARS WINDS WILL BECOME SOUTHERLY...BRINGING
IMPROVEMENT TO AT LEAST MVFR AS UPSLOPE COMPONENT IS LOST. LOW MVFR
POSSIBLE IFR MAY RETURN TO KCMX SUN AFTN AS COLD FRONT SAGS THRU THE
AREA AND WINDS SHIFT BACK TO AN UPSLOPE EASTERLY DIRECTION.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS. THE LOW PRESSURE SYSTEM
WILL SLIDE SOUTH OF LAKE SUPERIOR WED...BUT THE PRESSURE GRADIENT
WILL BE WEAKER THAN EARLIER IN THE WEEK...SO LIGHTER ELY WINDS ARE
EXPECTED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS

000
FXUS63 KGRR 190004
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
804 PM EDT SAT MAY 18 2013

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 311 PM EDT SAT MAY 18 2013

LOW PRESSURE DEVELOPING IN COLORADO WILL TRACK SLOWLY EAST OVER
THE NEXT COUPLE OF DAYS. SOUTHEAST WINDS AHEAD OF THIS SYSTEM WILL
DRAW WARMER AND INCREASINGLY MOIST AIR INTO THE GREAT LAKES
REGION.  AS A RESULT NUMEROUS SHOWERS AND THUNDERSTORMS ARE FORECAST
TO ARRIVE BY MONDAY. THIS UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE MIDDLE PART OF THE WEEK.

&&

.UPDATE...
ISSUED AT 804 PM EDT SAT MAY 18 2013

NO UPDATES TO THE FORECAST THIS EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 311 PM EDT SAT MAY 18 2013

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THUNDERSTORM
AND SEVERE WEATHER POTENTIAL ON MONDAY.

THE COMBINATION OF UPPER LEVEL DIVERGENCE...INCREASING DEEP LAYER
SHEAR...ARRIVAL OF GULF MOISTURE AND BUILDING CAPE SUPPORTS AN
INCREASED RISK FOR ORGANIZED CONVECTION MONDAY INTO MONDAY NIGHT.
MID LEVEL LAPSE RATES STEEPEN TO 7.5 TO 8 DEG C/KM.  A 20 TO 30
KNOT LOW LEVEL JET SETS UP JUST SOUTH OF THE MI BORDER MONDAY AND
STAYS THERE THROUGH MON NIGHT. THIS SHOULD FOCUS THE CONVECTION IN
LOWER MI THROUGH THAT PERIOD. THE SURFACE WARM FRONT WILL BE
LIFTING THROUGH AT THAT TIME WHICH WILL ALSO HELP TO PROVIDE A
FOCUS FOR THE CONVECTION. MODELS ARE IN DECENT AGREEMENT ON THIS
SCENARIO. SO WILL FEATURE NUMEROUS SHOWERS AND THUNDERSTORMS FOR
THIS PERIOD. I SUSPECT WE WILL SEE MORE THAN ON ROUND OF
CONVECTION IN THIS TIME FRAME. RAINFALL COULD BE HEAVY AND REPEAT
OVER THE SAME REGION GIVEN THE FRONTAL ZONE WILL BECOME NEARLY
PARALLEL TO THE MID TO UPPER LEVEL FLOW.

I CONSIDERED ADDING A SMALL CHANCE FOR A STORM SUNDAY AFTERNOON
CLOSER TO THE LAKE SHORE. A LAKE BREEZE WILL TRY TO DEVELOP. WHILE
SOME INSTABILITY WILL BE PRESENT...THE MOISTURE IS STILL SOMEWHAT
LIMITED. THERE IS A WEAK CAP/WARM LAYER NOTED IN FORECAST
SOUNDINGS UP AROUND 650 MB AS WELL. SO WILL KEEP IT DRY. IT WILL
BE A WARM DAY WITH MOST LOCATIONS TOPPING OUT IN THE LOW TO MID
80S. I DID WARM TEMPERATURES UP ALONG THE SHORELINE AS THE FLOW
WILL FEATURE AN OFFSHORE COMPONENT TO START THE DAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT MAY 18 2013

AN ACTIVE WEATHER PATTERN WILL BE UNDERWAY TUESDAY AS A SLOW MOVING
LOW MIGRATES FROM THE PLAINS EASTWARD. A STATIONARY FRONT EXTENDING
EASTWARD FROM THE LOW WILL BE A FOCUS FOR SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. PWAT VALUES NEAR 1.75 INCHES SUGGESTS A HEAVY
RAIN POTENTIAL. MODELS CERTAINLY SHOW QUITE A BIT OF INSTABILITY
WITH LI/S NEAR -8C AND MLCAPE AROUND 2500 J/KG SHEAR VALUES IN THE
45-50KT RANGE POINT TOWARD A SVR POTENTIAL TOO. NO ONE TIME PERIOD
LOOKS MORE FAVORABLE THAN ANOTHER. OF COURSE AFTERNOON INSTABILITY
MAY BE KEY. HOWEVER WITH THE FRONT NEARBY...ELEVATED STORMS COULD BE
POSSIBLE TOO AND BE LESS INFLUENCED BY DAYTIME HEATING. THE LLJ
ISN/T ALL THAT IMPRESSIVE WITH THE SYSTEM BUT MOISTURE TRANSPORT
LOOKS ADEQUATE FOR STORM INITIATION.

AS THE LOW MOVES OVERHEAD WEDNESDAY NIGHT AND THURSDAY WE SHOULD SEE
THUNDERSTORM CHANCES DECREASE IN FAVOR OF SHOWERS. A DRYING TREND
WILL GREET THE BEGINNING OF THE MEMORIAL DAY WEEKEND RESULTING IN PT
CLDY SKIES WITH HIGHS IN THE MID 60S AND LOWS IN THE MID 40S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 716 PM EDT SAT MAY 18 2013

SOME MVFR VISIBILITIES IN FOG MAY DEVELOP FOR ABOUT THREE TO SIX
HOURS TOWARD DAYBREAK SUNDAY. OTHERWISE...VFR CONDITIONS EXPECTED
THROUGH THE FORECAST PERIOD.


&&

.MARINE...
ISSUED AT 311 PM EDT SAT MAY 18 2013

WATER TEMPERATURES WILL BE ON THE RISE INTO EARLY NEXT. WHILE WE
HAVE OFFSHORE FLOW...IT IS NOT THAT STRONG. THE FLOW VEERS TO THE
SOUTH AND THE AIR TEMPERATURE WARMS. ALSO MOISTURE WILL BE ON THE INCREASE.
TYPICALLY IN THESE SETUPS WATER TEMPERATURES CLIMB RATHER QUICKLY. WILL
NEED TO MONITOR THE FOG SETUP AS SURFACE DEW POINTS WILL CLIMB INTO
THE 60S. THE STABLE COLDER WATER TEMPERATURES GENERALLY IN THE LOW 40S WILL
LIMIT THE WAVE DEVELOPMENT.


&&

.FIRE WEATHER...
ISSUED AT 311 PM EDT SAT MAY 18 2013
WARM AND DRY INTO SUNDAY. MOISTURE WILL BE ON THE INCREASE AND
THAT WILL KEEP HUMIDITY LEVELS UP. WIND VALUES WILL BE RELATIVELY
LIGHT DUE TO THE WEAKER PRESSURE GRADIENT.

&&

.HYDROLOGY...
ISSUED AT 311 PM EDT SAT MAY 18 2013

GULF MOISTURE WILL BE STREAMING INTO LOWER MICHIGAN THROUGH THE
MIDDLE PART OF THE WEEK. THIS WILL INCREASE THE RISK FOR HEAVIER
RAIN. THE MAIN TIME FRAME FOR POTENTIAL HEAVY RAIN WILL EXIST
BETWEEN MONDAY AND WEDNESDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MACZKO
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...MACZKO
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KAPX 182328
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
728 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 316 PM EDT SAT MAY 18 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE
PLAINS...BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK.
THIS APPROACHING SYSTEM WILL GENERATE THUNDERSTORMS AND MILD
TEMPERATURES...OVER NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.UPDATE...
ISSUED AT 728 PM EDT SAT MAY 18 2013

VERY SPOTTY SPRINKLES/-SHRA RESTRICTED TO EASTERN UPPER MI (MAINLY
CHIPPEWA CO). TWIN SAULTS BOTH REPORTING OFF-AND-ON RAIN IN THE
PAST COUPLE OF HOURS. CLOUD COVER HAS DIMINISHED CONSIDERABLY IN
NORTHERN LOWER MI...WITH SOME PARTIAL CLEARING AS FAR NORTH AS WESTERN
MACKINAC. PRECIP FORECAST SEEMS TO BE IN GOOD SHAPE...WILL
CONTINUE TO BABYSIT CLOUD TRENDS AND ADJUST AS NEEDED.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

ELEVATED WARM FRONT/WARM AIR ADVECTION WING CONTINUES TO LIFT THRU
THE AREA TONIGHT WITH LINGERING MID LEVEL FGEN AND ADIABATIC OMEGA
POSSIBLY PRODUCING A FEW SPRINKLES/LIGHT SHOWER TIP OF THE MITT INTO
EASTERN UPPER.  SKY CONDITIONS RANGING FROM PARTLY CLOUDY SOUTH TO
MOSTLY CLOUDY NORTH.  A MILD NIGHT WITH LOWS FROM THE MID 40S TO
LOWER 50S.

BY FAR THE BEST DAY OF THE WEEKEND ON SUNDAY WITH 850MB THERMAL
RIDGE OF 13-15C BUILDING INTO THE AREA.  MID LEVEL RIDGING WILL
CONTINUE TO DOMINATE OUR WEATHER PICTURE AS DEEPER TROUGH DIGS INTO
THE NORTHERN PLAINS.  SFC DEWPOINTS WILL CONTINUE TO GRADUALLY CREEP
UP AS THE DAY PROGRESSES.  NAM CONTINUING ITS RECENT BIAS OF TOO WET
LOWER LEVELS...WITH CURRENT FCST DEWPOINTS 3-5 DEGF TOO HIGH BASED
ON LATEST OBSERVATIONS.  QUITE WARM ON SUNDAY...WITH HIGH TEMPS
REACHING THE MIDDLE 70S /EASTERN UPPER/ TO LOWER 80S /PORTIONS OF
NORTHERN LOWER/.  WEAK GRADIENT AND WARM TEMPS LEND ITSELF TO LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON HOURS AND WILL COOL TEMPS
CLOSER TO THE COASTS TO ACCOUNT FOR THIS.  EVEN WITH SLIGHTLY LOWER
DWPTS THAN THE NAM FCST SOUNDINGS...MODIFIED SOUNDINGS WITH NEAR DRY
ADIABATIC MIXED LAYER YIELD SEVERAL HUNDRED JOULES OF SKINNY CAPE.
INLAND PENETRATING LAKE BREEZE BOUNDARIES...INCREASING SFC DWPTS AND
SOME INSTABILITY SUPPORT ISOLATED SHOWER MENTION FOR INTERIOR AREAS
DURING THE MID/LATE AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

MID AND UPPER LEVEL PATTERN BECOMING INCREASINGLY BLOCKY WITH
TIME...AT LEAST PARTIALLY DRIVEN BY STRONG NORTH CENTRAL ATLANTIC
CENTERED HIGH PRESSURE RIDGE AXIS. DUAL STRONG SHORTWAVE TROUGHS
DIVING INTO THE PACIFIC NORTHWEST ONLY HELPING THE CAUSE...WITH LEAD
ENERGY EVENTUALLY CARVING OUT A SLOW MOVING UPPER LOW IN THE NATIONS
MIDSECTION EARLY NEXT WORK WEEK...WHILE THE NEXT PIECE DOES THE SAME
ACROSS THE PACIFIC NORTHWEST. SUBSEQUENT CANADIAN PRAIRIE RIDGE
BUILDING BETWEEN THESE FEATURES SETS UP A QUASI-OMEGA BLOCK
SIGNATURE...WITH STRONG ENERGY PROGGED TO DIVE DOWN ITS FRONTSIDE
INTO EAST CENTRAL CANADA ONLY ADDING FURTHER COMPLEXITY TO AN
ALREADY COMPLEX PATTERN. ADD IN A GOOD SUPPLY OF GULF OF MEXICO
MOISTURE AND FGEN DYNAMICS...AND THE PATTERN HAS ALL THE MAKINGS OF
A WET ONE THROUGH AT LEAST THE FIRST HALF OF THIS UPCOMING WEEK.
LATEST WPC 5 AND 7 DAY QUANTITATIVE PRECIPITATION FORECASTS
CONCUR...WITH WIDESPREAD 1 TO 2 INCH AMOUNTS ACROSS OUR AREA...WITH
HEAVIER AMOUNTS TO UPWARDS OF 4 INCHES JUST TO OUR NORTHWEST. AS ONE
CAN IMAGINE GIVEN ABOVE...EXTENDED FORECAST CONCERNS MAINLY CENTER
ON MULTI-PERIOD RAIN SHOWER AND THUNDERSTORM THREATS.

ONE COMPLICATED FORECAST SUNDAY NIGHT INTO MONDAY...WHICH...TO BE
HONEST...DOES NOT SUPPORT A WHOLE LOT OF FORECAST CONFIDENCE.
CENTRAL PLAINS CLOSED LOW BECOMES INCREASINGLY WELL ESTABLISHED...
WITH EXCELLENT FORCED LOW/MID LEVEL CONVERGENCE ZONE SETTING UP
BETWEEN SOUTH FLOW OUT AHEAD OF IT WEAK ENERGY DIVING THROUGH
ONTARIO. STRONG H8 CONVERGENCE AXIS LOOKS TO SLOWLY SAG SOUTH ACROSS
LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY...WITH SURFACE REFLECTION
ESSENTIALLY REMAINING STATIONARY ACROSS THE CLIMATOLOGICALLY FAVORED
TIP OF THE MITT/STRAITS REGION. H8 FRONT LOOKS TO REMAIN VERY
ACTIVE...FOCUSING MUCH OF THE RAIN OFF TO OUR NORTH THROUGH SUNDAY
NIGHT...PERHAPS INTO THE FIRST PART OF MONDAY (HELPED IN PART BY MID
LEVEL RIDGING REMAINING OVERHEAD). CONDITIONS BECOME MUCH MORE
INTERESTING HEADING INTO MONDAY AFTERNOON AND NIGHT AS ENERGY
ROTATING AROUND UPPER LEVEL LOW INTERACTS WITH AN INCREASINGLY
IMPRESSIVE OVERHEAD MOISTURE PLUME AS PWAT VALUES APPROACH AN INCH
AND A HALF. WHILE MODEL DEPICTED SURFACE DEWPOINTS IN THE UPPER
60S/LOWER 70S SEEM AGGRESSIVE...JUXTAPOSITION OF DECENT MOISTURE AND
MID LEVEL SUPPORT SHOULD BE ENOUGH TO KICK OFF ROUNDS OF SHOWERS AND
STORMS...SOME OF WHICH MAY BRING LOCALLY HEAVY RAINFALL. WHILE
SEVERE THREAT NOT COMPLETELY ZERO...BETTER POTENTIAL SHOULD REMAIN
TO OUR SOUTHWEST WITHIN CORRIDOR OF MUCH MORE IMPRESSIVE DEEP LAYER
SHEAR AND BETTER LOW LEVEL INSTABILITY. LATEST DAY 3 SPC SEVERE
GRAPHICS DOES BRING THE SLIGHT RISK RIGHT TO OUR DOORSTEP OVER
SOUTHWEST MICHIGAN. NO DOUBT WORTH KEEPING AN EYE ON THE NEXT FEW
DAYS AS UPSTREAM CONVECTIVE TRENDS WILL LIKELY PLAY HAVOC WITH EXACT
THERMODYNAMIC AND KINEMATIC DETAILS. POTENTIALLY ANOTHER WARM ONE
MONDAY...ESPECIALLY SOUTH OF THE BRIDGE. THERMAL PROGS EASILY
SUPPORT HIGHS BACK INTO THE LOWER 80S...ALTHOUGH CLOUD AND
CONVECTIVE TRENDS MAY PREVENT FULL WARMING FROM BEING REALIZED.

MID-WEEK WEATHER DEPENDENT ON INTERACTION (OR LACK THEREOF) BETWEEN
APPROACHING MID LEVEL LOW AND STRONGER ENERGY DIVING SOUTH OUT OF
CANADA. THE FORMER CONTINUES TO SUPPLY PLENTY OF MOISTURE AND
DYNAMICS...WHILE THE LATTER ATTEMPTS TO DRIVE BEST FGEN/BAROCLINIC
ZONE FURTHER SOUTH WITH TIME. DEEP LAYER CONVERGENCE AND MOISTURE
SUPPORTS PLENTY OF RAIN POTENTIAL...WITH PLACEMENT OF THE HEAVIEST
AND STEADIEST RAINFALL TIED TO ABOVE INTERACTION. 00Z ECMWF/GEM
OFFER A RATHER WET SCENARIO...KEEPING CORRIDOR OF DEEP LAYER
CONVERGENCE OVERHEAD RIGHT THROUGH THURSDAY. GFS A TOUCH MORE
AGGRESSIVE DRIVING THIS CORRIDOR SOUTH...ALTHOUGH IT TOO SUGGESTS
LINGERING RAINS INTO THURSDAY (JUST NOT AS HEAVY). HARD TO GET A
FEEL FOR WHICH IS MORE CORRECT...WITH THE END RESULT LIKELY A MIDDLE
GROUND BETWEEN THE TWO. INHERITED FORECAST KEEPS RAINS LINGERING
THROUGH THURSDAY...AS WILL THIS FORECAST. SEVERE THREAT SHOULD ONLY
SAG SOUTH WITH TIME AS LOW LEVEL BAROCLINIC ZONE DOES THE SAME. THAT
SAID...PROXIMITY OF IT AND SOME EVIDENCE FOR IT TO RETURN BRIEFLY
NORTH LATER WEDNESDAY...AS MAIN WESTERN ENERGY APPROACHES...
DEFINITELY RAISES SOME CONCERN.

START OF MEMORIAL DAY WEEKEND LOOKING COOL AND DRY AS CANADIAN HIGH
PRESSURE BUILDS OVERHEAD. HIGHS FRIDAY AND SATURDAY LOOK TO ONLY
REACH INTO 60S (UPPER 50S ACROSS EASTERN UPPER?)...WHICH WOULD BE AT
LEAST A FEW DEGREES BELOW NORMAL. PATTERN RECOGNITION SUPPORTS THE
POTENTIAL FOR SOME RATHER CHILLY OVERNIGHT READINGS THURSDAY THROUGH
SATURDAY. SOMEWHAT DISCONCERTING TO SEE LATEST CLIMO INFLUENCED
ECMWF MOS SHOWING COLDER LOCATIONS DIPPING INTO THE MIDDLE AND UPPER
30S EARLY FRIDAY MORNING...AND WIDESPREAD LOWER AND MIDDLE 30 DEGREE
READINGS SATURDAY MORNING. OTHER GUIDANCE NOT QUITE AS COLD...BUT
DEFINITELY SOMETHING TO MONITOR.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 728 PM EDT SAT MAY 18 2013

VFR.

LIGHT SOUTHERLY FLOW IN PLACE IN THE LOW AND MID LEVELS...BETWEEN
HIGH PRESSURE OVER EASTERN CANADA...AND LOW PRESSURE IN THE CENTRAL/
SOUTHERN HIGH PLAINS. THIS WILL SLOWLY BRING MORE LOW-LEVEL MOISTURE
INTO THE REGION. INITIALLY...BAND OF MID/HIGH CLOUDS WILL CONTINUE
TO LIFT NORTH OUT OF NORTHERN LOWER TONIGHT. PATCHY MID CLOUDS
WILL RETURN TO NORTHERN LOWER OVERNIGHT FROM THE SOUTH. SUNDAY
WILL BE SUNNIER...WARMER...AND SOMEWHAT MORE HUMID. DEVELOPING LAKE
BREEZES WILL LIKELY TRIGGER A FEW SHRA IN THE AFTERNOON...BUT
INLAND FROM ALL THE TAF SITES.

LIGHT WINDS TONIGHT INTO SUNDAY MORNING...WITH ONSHORE WINDS
DEVELOPING EARLY SUNDAY AFTERNOON.

&&

.MARINE...
ISSUED AT 316 PM EDT SAT MAY 18 2013

GRADIENT WILL REMAIN RELATIVELY WEAK OVER THE NEXT FEW DAYS AS HIGH
PRESSURE SLOWLY DEPARTS TO THE EAST. AS LOW PRESSURE DRAWS CLOSER
TO THE AREA TUESDAY/WEDNESDAY...WINDS WILL INCREASE AND SMALL
CRAFT CONDITIONS ARE POSSIBLE.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...MB
AVIATION...JZ
MARINE...JK

000
FXUS63 KGRR 182316
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
716 PM EDT SAT MAY 18 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 311 PM EDT SAT MAY 18 2013

LOW PRESSURE DEVELOPING IN COLORADO WILL TRACK SLOWLY EAST OVER
THE NEXT COUPLE OF DAYS. SOUTHEAST WINDS AHEAD OF THIS SYSTEM WILL
DRAW WARMER AND INCREASINGLY MOIST AIR INTO THE GREAT LAKES
REGION.  AS A RESULT NUMEROUS SHOWERS AND THUNDERSTORMS ARE FORECAST
TO ARRIVE BY MONDAY. THIS UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE MIDDLE PART OF THE WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 311 PM EDT SAT MAY 18 2013

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THUNDERSTORM
AND SEVERE WEATHER POTENTIAL ON MONDAY.

THE COMBINATION OF UPPER LEVEL DIVERGENCE...INCREASING DEEP LAYER
SHEAR...ARRIVAL OF GULF MOISTURE AND BUILDING CAPE SUPPORTS AN
INCREASED RISK FOR ORGANIZED CONVECTION MONDAY INTO MONDAY NIGHT.
MID LEVEL LAPSE RATES STEEPEN TO 7.5 TO 8 DEG C/KM.  A 20 TO 30
KNOT LOW LEVEL JET SETS UP JUST SOUTH OF THE MI BORDER MONDAY AND
STAYS THERE THROUGH MON NIGHT. THIS SHOULD FOCUS THE CONVECTION IN
LOWER MI THROUGH THAT PERIOD. THE SURFACE WARM FRONT WILL BE
LIFTING THROUGH AT THAT TIME WHICH WILL ALSO HELP TO PROVIDE A
FOCUS FOR THE CONVECTION. MODELS ARE IN DECENT AGREEMENT ON THIS
SCENARIO. SO WILL FEATURE NUMEROUS SHOWERS AND THUNDERSTORMS FOR
THIS PERIOD. I SUSPECT WE WILL SEE MORE THAN ON ROUND OF
CONVECTION IN THIS TIME FRAME. RAINFALL COULD BE HEAVY AND REPEAT
OVER THE SAME REGION GIVEN THE FRONTAL ZONE WILL BECOME NEARLY
PARALLEL TO THE MID TO UPPER LEVEL FLOW.

I CONSIDERED ADDING A SMALL CHANCE FOR A STORM SUNDAY AFTERNOON
CLOSER TO THE LAKESHORE. A LAKE BREEZE WILL TRY TO DEVELOP. WHILE
SOME INSTABILITY WILL BE PRESENT...THE MOISTURE IS STILL SOMEWHAT
LIMITED. THERE IS A WEAK CAP/WARM LAYER NOTED IN FORECAST
SOUNDINGS UP AROUND 650 MB AS WELL. SO WILL KEEP IT DRY. IT WILL
BE A WARM DAY WITH MOST LOCATIONS TOPPING OUT IN THE LOW TO MID
80S. I DID WARM TEMPERATURES UP ALONG THE SHORELINE AS THE FLOW
WILL FEATURE AN OFFSHORE COMPONENT TO START THE DAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 311 PM EDT SAT MAY 18 2013

AN ACTIVE WEATHER PATTERN WILL BE UNDERWAY TUESDAY AS A SLOW MOVING
LOW MIGRATES FROM THE PLAINS EASTWARD. A STATIONARY FRONT EXTENDING
EASTWARD FROM THE LOW WILL BE A FOCUS FOR SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. PWAT VALUES NEAR 1.75 INCHES SUGGESTS A HEAVY
RAIN POTENTIAL. MODELS CERTAINLY SHOW QUITE A BIT OF INSTABILITY
WITH LI/S NEAR -8C AND MLCAPE AROUND 2500 J/KG SHEAR VALUES IN THE
45-50KT RANGE POINT TOWARD A SVR POTENTIAL TOO. NO ONE TIME PERIOD
LOOKS MORE FAVORABLE THAN ANOTHER. OF COURSE AFTERNOON INSTABILITY
MAY BE KEY. HOWEVER WITH THE FRONT NEARBY...ELEVATED STORMS COULD BE
POSSIBLE TOO AND BE LESS INFLUENCED BY DAYTIME HEATING. THE LLJ
ISN/T ALL THAT IMPRESSIVE WITH THE SYSTEM BUT MOISTURE TRANSPORT
LOOKS ADEQUATE FOR STORM INITIATION.

AS THE LOW MOVES OVERHEAD WEDNESDAY NIGHT AND THURSDAY WE SHOULD SEE
THUNDERSTORM CHANCES DECREASE IN FAVOR OF SHOWERS. A DRYING TREND
WILL GREET THE BEGINNING OF THE MEMORIAL DAY WEEKEND RESULTING IN PT
CLDY SKIES WITH HIGHS IN THE MID 60S AND LOWS IN THE MID 40S.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 716 PM EDT SAT MAY 18 2013

SOME MVFR VISIBILITIES IN FOG MAY DEVELOP FOR ABOUT THREE TO SIX
HOURS TOWARD DAYBREAK SUNDAY. OTHERWISE...VFR CONDITIONS EXPECTED
THROUGH THE FORECAST PERIOD.

&&

.MARINE...
ISSUED AT 311 PM EDT SAT MAY 18 2013

WATER TEMPERATURES WILL BE ON THE RISE INTO EARLY NEXT. WHILE WE
HAVE OFFSHORE FLOW...IT IS NOT THAT STRONG. THE FLOW VEERS TO THE
SOUTH AND THE AIR TEMPERATURE WARMS. ALSO MOISTURE WILL BE ON THE INCREASE.
TYPICALLY IN THESE SETUPS WATER TEMPERATURES CLIMB RATHER QUICKLY. WILL
NEED TO MONITOR THE FOG SETUP AS SURFACE DEW POINTS WILL CLIMB INTO
THE 60S. THE STABLE COLDER WATER TEMPERATURES GENERALLY IN THE LOW 40S WILL
LIMIT THE WAVE DEVELOPMENT.


&&

.FIRE WEATHER...
ISSUED AT 311 PM EDT SAT MAY 18 2013
WARM AND DRY INTO SUNDAY. MOISTURE WILL BE ON THE INCREASE AND
THAT WILL KEEP HUMIDITY LEVELS UP. WIND VALUES WILL BE RELATIVELY
LIGHT DUE TO THE WEAKER PRESSURE GRADIENT.

&&

.HYDROLOGY...
ISSUED AT 311 PM EDT SAT MAY 18 2013

GULF MOISTURE WILL BE STREAMING INTO LOWER MICHIGAN THROUGH THE
MIDDLE PART OF THE WEEK. THIS WILL INCREASE THE RISK FOR HEAVIER
RAIN. THE MAIN TIME FRAME FOR POTENTIAL HEAVY RAIN WILL EXIST
BETWEEN MONDAY AND WEDNESDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...MACZKO
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KDTX 182315
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
715 PM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

DRY LOW LEVEL EASTERLY FLOW ASSOCIATED WITH THE LARGE HIGH TO THE
EAST OF THE STATE WILL MAINTAIN TRANQUIL CONDITIONS THROUGH THE
EVENING AS THE LOSS IN DAYTIME HEATING WILL ALLOW A SLIGHT DECLINE
IN THE WIND SPEEDS. THE LOW LEVEL FLOW WILL VEER TOWARD THE S-SE
OVERNIGHT. THIS WILL ADVECT SOME LOW LEVEL MOISTURE INTO SE MI WHICH
MAY PRESENT ITSELF AS SOME HAZE TOWARD DAYBREAK.

FOR DTW...SOME VISIBILITY REDUCTION DUE TO HAZE IS POSSIBLE AROUND
DAYBREAK ALTHOUGH CONFIDENCE IS NOT TOO TERRIBLY HIGH CONSIDERING
THE MAGNITUDE OF LOW LEVEL DRY AIR NOW BLANKETING THE EASTERN GREAT
LAKES REGION.

//DTW THRESHOLD THREATS...

* NONE

&&

.PREV DISCUSSION...ISSUED 338 PM EDT SAT MAY 18 2013

SHORT TERM...THIS EVENING AND TONIGHT

DOWNSTREAM AMPLIFICATION OF THE EASTERN NORTH AMERICA RIDGE WILL
OCCUR TONIGHT AS STRONG JET ENERGY DIGS THROUGH THE FOUR CORNERS.
THE MAIN CONSEQUENCE OF THIS DURING THE SHORT TERM IS THE APEX OF
THE RIDGE WILL SHARPEN AND LIFT INTO JAMES BAY GUIDING THE
CONSOLIDATED JET CORE ALONG WITH IT. THE NET RESULT IS FOR THE PESKY
ALTOSTRATUS THAT HAS BEEN HARBORED WITHIN THE SHEARING DEFORMATION
AXIS OVER NORTHERN LOWER MICHIGAN...SAGINAW BAY...THUMB TO EXIT WITH
TIME. MEANWHILE...WATER VAPOR IMAGERY SHOWS SMALLER WAVELENGTH
ANTICYCLONIC MOTION OVER PORTIONS OF NORTHEASTERN ILLINOIS AND LAKE
MICHIGAN FOLDING OVER. THIS HIGHLIGHTS THE INCREASING RIDGING ALOFT
THROUGH TONIGHT.

SOME MODIFICATION TO THE AIR MASS IN COMBINATION WITH A TREND VERY
LATE FOR SOME INCREASINGLY SOUTHERLY FLOW SUGGESTS A GOOD 2 TO 3
DEGREES WARMER TONIGHT. LOWS SHOULD DIP INTO THE LOWER 50S
NORTH...MIDDLE 50S SOUTH.

LONG TERM...SUNDAY THROUGH NEXT SATURDAY

UPPER RIDGE WILL HOLD OVER MICHIGAN FOR ONE MORE DAY TOMORROW.
SUBSIDENCE UNDER THE RIDGE SHOULD PREVENT SHOWERS/TSTORMS FROM
DEVELOPING...ALTHOUGH WE WILL BUILD UP SOME INSTABILITY DURING THE
DAY AS THE GROUND HEATS AND LAPSE RATES STEEPEN. SOUTHEAST WINDS
WILL REDUCE POTENTIAL FOR LOW-LEVEL CONVERGENCE NEAR THE LAKESHORES
(NO CONVECTIVE TRIGGER)...AND WILL ALSO HOLD TEMPERATURES CLOSER TO
THE SHORELINES INTO THE 70S. LOW 80S ARE EXPECTED WELL INLAND AS
GOOD INSOLATION COMBINES WITH RISING TEMPS AT 925-850MB. FRONTAL
BOUNDARY BY THIS POINT WILL ALSO BE POISED NORTH OF LAKE
HURON...HAVING LITTLE IMPACT ON WEATHER FOR SUNDAY BUT WILL BECOME A
FACTOR IN OUR WEATHER THROUGH MOST OF NEXT WEEK.

UPPER WAVE OFF THE PACIFIC NORTHWEST COAST WILL BECOME ABSORBED IN
THE BROAD UPPER TROUGH NOW ALONG AND WEST OF THE ROCKIES. MODELS
SHOW THIS SYSTEM CLOSING OFF OVER THE CENTRAL PLAINS ON
MONDAY...THEN VERY SLOWLY WORKING EAST INTO THE GREAT LAKES/OHIO
VALLEY BY THURSDAY. ARRIVAL OF THIS SYSTEM HAS BEEN HARD TO
PREDICT AS IT WILL EITHER CUT-OFF FROM MAIN FLOW OR REMAIN UNDER
VERY LIGHT STEERING FLOW. MODELS CONTINUE TO DISPLAY SOME TIMING
DIFFERENCES WITH ITS ENTRANCE AND EXIT INTO THE AREA...IN PART DUE
TO TIMING/PLACEMENT ISSUES WITH ANOTHER UPPER LOW DROPPING THROUGH
EASTERN CANADA. OVERALL CONFIDENCE IN THE FORECAST MONDAY AFTERNOON
THROUGH THURSDAY IS NOT HIGH...OTHER THAN TO SAY ROUNDS OF SHOWERS
AND THUNDERSTORMS WILL LIKELY ROLL THROUGH AND AFFECT EVERYTHING
FROM CLOUD COVER TO TEMPERATURES.

CHANCES FOR PRECIPITATION WILL START TO INCREASE LATE SUNDAY NIGHT
AND MONDAY MORNING AS A WEAK LOW-LEVEL JET NOSES TOWARDS LAKE
MICHIGAN. WEAK PUSH OF THETA-E ADVECTION COINCIDING WITH THIS COULD
TRIGGER A FEW SHOWERS/TSTORMS...AND HAVE MAINTAINED LOW POPS THROUGH
THE FIRST PART OF THE DAY ON MONDAY. MODELS THEN IN GREAT AGREEMENT
WITH CLIPPING SHORTWAVE ENERGY UP THROUGH LOWER MICHIGAN AS IT RIDES
SOUTHWEST FLOW PRECEDING THE LARGE LOW PRESSURE SYSTEM. MODEL TIMING
OF THIS WAVE VARIES FROM LATE MORNING THROUGH EARLY EVENING.
CONSENSUS DOES BRING IT THROUGH DURING THE LATE AFTERNOON...RIGHT AT
PEAK HEATING...AND WILL CONTINUE TO ANTICIPATE A FAIRLY GOOD
COVERAGE OF SHOWERS/TSTORMS DEVELOPING. CHANCES MAY BE BETTER
FURTHER NORTH OVER CENTRAL MICHIGAN...AS THE FRONTAL BOUNDARY NORTH
OF LAKE HURON STARTS TO DROP SOUTHWARD. THE FRONT WILL THEN BECOME
QUASI-STATIONARY OVER LOWER MICHIGAN (BEST SUPPORT FOR EITHER
CENTRAL OR NORTHERN LOWER) TUESDAY THROUGH EARLY WEDNESDAY...WHILE
ADDITIONAL UPPER SHORTWAVES EJECTING OUT OF THE LOW AND MCVS FROM
UPSTREAM CONVECTION RIDE OVER THE FRONT OR WITHIN THE WARM SECTOR
AND TRIGGER ADDITIONAL ROUNDS OF CONVECTION. THE FRONT SHOULD LIFT
BACK NORTH LATE ON WEDNESDAY AS THE LOW APPROACHES AND CROSSES THE
REGION...BEFORE DROPPING BACK SOUTH AS A STRONG COLD FRONT ON
THURSDAY.

TEMPERATURES WILL BE VERY UNCERTAIN WITH ROUNDS OF SHOWERS/TSTORMS
AND CLOUD REMNANTS FROM UPSTREAM CONVECTION CROSSING OVERHEAD.
ASSUMING A PRETTY DRY START TO THE DAY...TEMPERATURES ON MONDAY
SHOULD WARM INTO THE 80S. REMAINED A LITTLE CONSERVATIVE WITH
FORECAST HIGHS THE LOW/MID 80S. IF CONVECTION WAITS UNTIL VERY LATE
AFTERNOON OR EVENING TO FIRE...SOME LOCATIONS COULD SEE UPPER 80S.

SEVERE WEATHER MAY BECOME A CONCERN MONDAY THROUGH WEDNESDAY. MODEL
SB CAPE VALUES OF 2500-3000 J/KG MAY BE REALIZED ON MONDAY IN A
"FRESH ATMOSPHERE" THAT HAS NOT BEEN WORKED OVER...ASSUMING NO
UPSTREAM REMNANTS ARRIVE EARLY IN THE DAY. STRONGER STORMS MAY ALSO
FIRE OVERNIGHT AND ESPECIALLY TUESDAY AS THE FRONT LOOKS TO SINK
SLIGHTLY SOUTHWARD INTO THE AREA...AND UPPER JET SUPPORT BECOMES
MORE FAVORABLE. MODEL SB CAPE VALUES CONTINUE TO LOOK CONDUCIVE FOR
STRONG/SEVERE STORMS WEDNESDAY AS THE LOW APPROACHES AND THE FRONT
LIFTS BACK NORTH. SHEAR VALUES DO NOT LOOK OVERLY IMPRESSIVE ANY OF
THE DAYS HOWEVER. LOCALLY HEAVY RAINFALL WILL ALSO BE A THREAT WITH
PW VALUES RUNNING BETWEEN 1.25-1.50+ INCHES DURING THIS ENTIRE
TIMEFRAME.

QUIET WEATHER IS THEN EXPECTED TOWARDS THE END OF THE WEEK AS HIGH
PRESSURE BUILDS OVER THE AREA...BUT TEMPERATURES WILL RUN MUCH
COOLER WITH MAX TEMPS ONLY IN THE 60S.

MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
SHORT TERM...CB
LONG TERM....HLO
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KMQT 182048
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
448 PM EDT SAT MAY 18 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

PRECIP OVER THE NRN HALF OF THE CWA THIS AFTERNOON IS BEING DRIVEN
BY MOISTURE TRANSPORT/WAA BEHIND AN 850MB WARM FRONT THAT IS
APPROACHING NERN LAKE SUPERIOR. SLY FLOW BEHIND THE FRONT BETWEEN
DEVELOPING LOW PRESSURE OVER THE PLAINS AND HIGH PRESSURE OVER
QUEBEC WILL CONTINUE TO STREAM WARMER TEMPS AND MOISTURE INTO THE
CWA TONIGHT...WHILE THE 850MB WARM FRONT STALLS OUT OVER THE NRN
CWA. THE FRONT STAYING OVER THE NRN CWA INTO TONIGHT WILL KEEP
PRECIP CHANCES HIGHEST OVER THE KEWEENAW PENINSULA...WITH LITTLE TO
NO PRECIP EXPECTED ELSEWHERE.

WITH 850MB TEMPS AROUND 14C SUN...AND LESS LOW LEVEL MOISTURE THAN
THE GFS/NAM SHOW AS HAS BEEN THE CASE LATELY...EXPECT HIGH TEMPS
AROUND 80 AWAY FROM MODERATING LAKE SUPERIOR. THE SYSTEM OVER THE
PLAINS WILL WRAP UP OVER SD BY 00Z MON WHILE SFC HIGH PRESSURE MOVES
FROM THE NRN TERRITORIES OF CANADA NOW TO NRN ONTARIO BY 00Z MON.
WITH THE SFC HIGH SLIDING TOWARD THE AREA BEHIND AN UPPER TROUGH AND
THE LOW CLOSING OFF TO THE W...EXPECT A SFC TROUGH TO SLIDE INTO THE
CWA LATER SUN. THIS WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS
TO MOVE BACK INTO THE WRN HALF OF THE CWA BY LATE SUN. FOR THE MOST
PART...GENERAL THUNDER IS EXPECT...BUT CAN NOT COMPLETELY RULE OUT A
STRONGER STORM OR TWO ALONG THE WI BORDER WITH 500-1000J/KG OF CAPE
AND AROUND 30KTS OF 0-6KM BULK SHEAR ALONG THE SRN CWA.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 446 PM EDT SAT MAY 18 2013

SUNDAY NIGHT...ALTHOUGH THERE WERE SOME DIFFERENCES...THE MODELS
WERE IN GENERAL AGREEMENT WITH THE POSITION OF THE MID LEVEL LOW
MOVING INTO CNTRL NEBRASKA AND THE SFC LOW TO SE SD BY 12Z MON. THE
SFC WARM FRONT WILL STRENGTHEN ACROSS SRN MN INTO SRN WI. EXPECT THAT
PCPN WILL INCREASE/EXPAND ACROSS THE WEST/CNTRL CWA WITH MOISTURE
INFLOW AND 300K-310K ISENTROPIC ASCENT ALONG THE 850-700 MB FRONT.
ALTHOUGH THE GREATEST INSTABILITY TO SUPPORT TSRA WILL REMAIN TO THE
SOUTH...SOME EMBEDDED ELEVATED CONVECTION WILL BE POSSIBLE.

MON INTO MON NIGHT...AS THE MID LEVEL LOW REMAINS NEARLY STATIONARY
OR MOVES SLIGHTLY TO THE EAST AND UPPER LEVEL DIV/700-300 MB QVECTOR
CONV FORCING FOR LARGE SCALE ASCENT REMAINS OVER THE AREA...SMALLER
SCALE SHORTWAVES MOVING THROUGH THE AREA WILL SUPPORT PERIODS OF RAIN
SHOWERS. HEAVY RAINFALL AMOUNTS OF 1 TO 2 INCHES REMAIN POSSIBLE WITH
ABUNDANT MOISTURE AVAILABLE (PWAT VALUES TO AROUND 1.5 INCHES...200
PERCENT OF NORMAL). ELEVATED TSRA CHANCES ALSO CONTINUE WITH MUCAPE
VALUES IN THE 500-1000 J/KG. CLOUD COVER AND PCPN WILL KEEP TEMPS
MAINLY TOWARD THE LOWER END OF GUIDANCE...ESPECIALLY DOWNWIND FROM
ERLY FLOW OFF OF THE GREAT LAKES.

TUE-WED...MODELS SUGGEST THAT THE BLOCKING/STAGNANT PATTERN WITH A
PROMINENT RIDGE OVER S CNTRL CANADA WILL FAVOR CONTINUED SLOW
PROGRESSION OF THE MID LEVEL LOW TO THE NE TO AROUND SE MN OR WRN WI
BY 00Z THU. SO...LIKELY OR HIGHER END CHANCE PCPN POPS WILL
CONTINUE. PCPN...THICKER CLOUDS AND PCPN WILL KEEP TEMPS BELOW
NORMAL.

THU-SAT...ALTHOUGH THE 00Z/12Z ECMWF WAS THE MOST AGGRESSIVE IN
BRINGING THE AREA UNDER THE INFLUENCE OF NW FLOW DOWNSTREAM FROM THE
BLOCKING RIDGE...THE GFS AND GFS ENSEMBLES ALSO HAVE TRENDED TOWARD
THAT SCENARIO. THIS WOULD FINALLY BRING DRIER AND COOL AIR INTO THE
REGION WITH TEMPS REMAINING BELOW NORMAL AS HIGH PRES BUILDS INTO THE
NRN GREAT LAKES FROM NRN ONTARIO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT MAY 18 2013

A WARM FNT MOVING IN FM THE SOUTH WILL BRING SOME -SHRA/MVFR CIGS
/LIFR CIGS AT CMX WITH UPSLOPE FLOW/...MAINLY AT IWD/CMX WHERE LLVL
WARM/MOIST ADVCTN WL BE MOST PRONOUNCED. MOIST UPSLOPE FLOW OFF LK
SUPERIOR MAY RESULT IN IFR CONDITIONS INTO THIS EVENING. FOLLOWING
THE WARM FROPA TONIGHT...EXPECT WSHFT TO THE S WITH RETURN TO
PREDOMINANT VFR WX. THE ONLY EXCEPTION WL BE AT CMX...WHERE
PERSISTENT UPSLOPE ESE WIND AND MOISTER LLVL AIR WL RESULT IN
LINGERING MVFR CONDITIONS THROUGH MUCH OF THE NIGHT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS. THE LOW PRESSURE SYSTEM
WILL SLIDE SOUTH OF LAKE SUPERIOR WED...BUT THE PRESSURE GRADIENT
WILL BE WEAKER THAN EARLIER IN THE WEEK...SO LIGHTER ELY WINDS ARE
EXPECTED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...TITUS
MARINE...TITUS

000
FXUS63 KDTX 181938
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
338 PM EDT SAT MAY 18 2013

.SHORT TERM...THIS EVENING AND TONIGHT

DOWNSTREAM AMPLIFICATION OF THE EASTERN NORTH AMERICA RIDGE WILL
OCCUR TONIGHT AS STRONG JET ENERGY DIGS THROUGH THE FOUR CORNERS.
THE MAIN CONSEQUENCE OF THIS DURING THE SHORT TERM IS THE APEX OF
THE RIDGE WILL SHARPEN AND LIFT INTO JAMES BAY GUIDING THE
CONSOLIDATED JET CORE ALONG WITH IT. THE NET RESULT IS FOR THE PESKY
ALTOSTRATUS THAT HAS BEEN HARBORED WITHIN THE SHEARING DEFORMATION
AXIS OVER NORTHERN LOWER MICHIGAN...SAGINAW BAY...THUMB TO EXIT WITH
TIME. MEANWHILE...WATER VAPOR IMAGERY SHOWS SMALLER WAVELENGTH
ANTICYCLONIC MOTION OVER PORTIONS OF NORTHEASTERN ILLINOIS AND LAKE
MICHIGAN FOLDING OVER. THIS HIGHLIGHTS THE INCREASING RIDGING ALOFT
THROUGH TONIGHT.

SOME MODIFICATION TO THE AIR MASS IN COMBINATION WITH A TREND VERY
LATE FOR SOME INCREASINGLY SOUTHERLY FLOW SUGGESTS A GOOD 2 TO 3
DEGREES WARMER TONIGHT. LOWS SHOULD DIP INTO THE LOWER 50S
NORTH...MIDDLE 50S SOUTH.

&&

.LONG TERM...SUNDAY THROUGH NEXT SATURDAY

UPPER RIDGE WILL HOLD OVER MICHIGAN FOR ONE MORE DAY TOMORROW.
SUBSIDENCE UNDER THE RIDGE SHOULD PREVENT SHOWERS/TSTORMS FROM
DEVELOPING...ALTHOUGH WE WILL BUILD UP SOME INSTABILITY DURING THE
DAY AS THE GROUND HEATS AND LAPSE RATES STEEPEN. SOUTHEAST WINDS
WILL REDUCE POTENTIAL FOR LOW-LEVEL CONVERGENCE NEAR THE LAKESHORES
(NO CONVECTIVE TRIGGER)...AND WILL ALSO HOLD TEMPERATURES CLOSER TO
THE SHORELINES INTO THE 70S. LOW 80S ARE EXPECTED WELL INLAND AS
GOOD INSOLATION COMBINES WITH RISING TEMPS AT 925-850MB. FRONTAL
BOUNDARY BY THIS POINT WILL ALSO BE POISED NORTH OF LAKE
HURON...HAVING LITTLE IMPACT ON WEATHER FOR SUNDAY BUT WILL BECOME A
FACTOR IN OUR WEATHER THROUGH MOST OF NEXT WEEK.

UPPER WAVE OFF THE PACIFIC NORTHWEST COAST WILL BECOME ABSORBED IN
THE BROAD UPPER TROUGH NOW ALONG AND WEST OF THE ROCKIES. MODELS
SHOW THIS SYSTEM CLOSING OFF OVER THE CENTRAL PLAINS ON
MONDAY...THEN VERY SLOWLY WORKING EAST INTO THE GREAT LAKES/OHIO
VALLEY BY THURSDAY. ARRIVAL OF THIS SYSTEM HAS BEEN HARD TO
PREDICT AS IT WILL EITHER CUT-OFF FROM MAIN FLOW OR REMAIN UNDER
VERY LIGHT STEERING FLOW. MODELS CONTINUE TO DISPLAY SOME TIMING
DIFFERENCES WITH ITS ENTRANCE AND EXIT INTO THE AREA...IN PART DUE
TO TIMING/PLACEMENT ISSUES WITH ANOTHER UPPER LOW DROPPING THROUGH
EASTERN CANADA. OVERALL CONFIDENCE IN THE FORECAST MONDAY AFTERNOON
THROUGH THURSDAY IS NOT HIGH...OTHER THAN TO SAY ROUNDS OF SHOWERS
AND THUNDERSTORMS WILL LIKELY ROLL THROUGH AND AFFECT EVERYTHING
FROM CLOUD COVER TO TEMPERATURES.

CHANCES FOR PRECIPITATION WILL START TO INCREASE LATE SUNDAY NIGHT
AND MONDAY MORNING AS A WEAK LOW-LEVEL JET NOSES TOWARDS LAKE
MICHIGAN. WEAK PUSH OF THETA-E ADVECTION COINCIDING WITH THIS COULD
TRIGGER A FEW SHOWERS/TSTORMS...AND HAVE MAINTAINED LOW POPS THROUGH
THE FIRST PART OF THE DAY ON MONDAY. MODELS THEN IN GREAT AGREEMENT
WITH CLIPPING SHORTWAVE ENERGY UP THROUGH LOWER MICHIGAN AS IT RIDES
SOUTHWEST FLOW PRECEDING THE LARGE LOW PRESSURE SYSTEM. MODEL TIMING
OF THIS WAVE VARIES FROM LATE MORNING THROUGH EARLY EVENING.
CONSENSUS DOES BRING IT THROUGH DURING THE LATE AFTERNOON...RIGHT AT
PEAK HEATING...AND WILL CONTINUE TO ANTICIPATE A FAIRLY GOOD
COVERAGE OF SHOWERS/TSTORMS DEVELOPING. CHANCES MAY BE BETTER
FURTHER NORTH OVER CENTRAL MICHIGAN...AS THE FRONTAL BOUNDARY NORTH
OF LAKE HURON STARTS TO DROP SOUTHWARD. THE FRONT WILL THEN BECOME
QUASI-STATIONARY OVER LOWER MICHIGAN (BEST SUPPORT FOR EITHER
CENTRAL OR NORTHERN LOWER) TUESDAY THROUGH EARLY WEDNESDAY...WHILE
ADDITIONAL UPPER SHORTWAVES EJECTING OUT OF THE LOW AND MCVS FROM
UPSTREAM CONVECTION RIDE OVER THE FRONT OR WITHIN THE WARM SECTOR
AND TRIGGER ADDITIONAL ROUNDS OF CONVECTION. THE FRONT SHOULD LIFT
BACK NORTH LATE ON WEDNESDAY AS THE LOW APPROACHES AND CROSSES THE
REGION...BEFORE DROPPING BACK SOUTH AS A STRONG COLD FRONT ON
THURSDAY.

TEMPERATURES WILL BE VERY UNCERTAIN WITH ROUNDS OF SHOWERS/TSTORMS
AND CLOUD REMNANTS FROM UPSTREAM CONVECTION CROSSING OVERHEAD.
ASSUMING A PRETTY DRY START TO THE DAY...TEMPERATURES ON MONDAY
SHOULD WARM INTO THE 80S. REMAINED A LITTLE CONSERVATIVE WITH
FORECAST HIGHS THE LOW/MID 80S. IF CONVECTION WAITS UNTIL VERY LATE
AFTERNOON OR EVENING TO FIRE...SOME LOCATIONS COULD SEE UPPER 80S.

SEVERE WEATHER MAY BECOME A CONCERN MONDAY THROUGH WEDNESDAY. MODEL
SB CAPE VALUES OF 2500-3000 J/KG MAY BE REALIZED ON MONDAY IN A
"FRESH ATMOSPHERE" THAT HAS NOT BEEN WORKED OVER...ASSUMING NO
UPSTREAM REMNANTS ARRIVE EARLY IN THE DAY. STRONGER STORMS MAY ALSO
FIRE OVERNIGHT AND ESPECIALLY TUESDAY AS THE FRONT LOOKS TO SINK
SLIGHTLY SOUTHWARD INTO THE AREA...AND UPPER JET SUPPORT BECOMES
MORE FAVORABLE. MODEL SB CAPE VALUES CONTINUE TO LOOK CONDUCIVE FOR
STRONG/SEVERE STORMS WEDNESDAY AS THE LOW APPROACHES AND THE FRONT
LIFTS BACK NORTH. SHEAR VALUES DO NOT LOOK OVERLY IMPRESSIVE ANY OF
THE DAYS HOWEVER. LOCALLY HEAVY RAINFALL WILL ALSO BE A THREAT WITH
PW VALUES RUNNING BETWEEN 1.25-1.50+ INCHES DURING THIS ENTIRE
TIMEFRAME.

QUIET WEATHER IS THEN EXPECTED TOWARDS THE END OF THE WEEK AS HIGH
PRESSURE BUILDS OVER THE AREA...BUT TEMPERATURES WILL RUN MUCH
COOLER WITH MAX TEMPS ONLY IN THE 60S.

&&

.MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.AVIATION...ISSUED 136 PM EDT SAT MAY 18 2013

//DISCUSSION...

PERSISTENT FLOW OFF OF THE CENTRAL GREAT LAKES AGGREGATE IS
ALLOWING SURFACE HIGH PRESSURE TO HOLD ON ACROSS SOUTHEASTERN
MICHIGAN. DRY AIR IN THE LOWEST 6 KFT AGL HAS BEEN THE STORY OF
RECENT DAYS AND WILL NOT BE GOING ANYWHERE ANYTIME SOON. MAIN
SHEARING DEFORMATION AXIS THAT IS IN PLACE OVER CENTRAL LOWER
MICHIGAN...SAGINAW BAY AND THUMB WILL LIFT NORTHWARD TODAY IN
RESPONSE TO BUILDING UPPER LEVEL HEIGHTS/LONGWAVE RIDGE AXIS.
THEREFORE...EXPECT VFR CONDITIONS WITH PERHAPS SOME MESSY MID TO
HIGH CLOUD AT TIMES. WILL BE WATCHING SOME LOWER LEVEL MOISTURE
LIFT ANTICYCLONICALLY OUT OF OHIO TONIGHT AND INTO PORTIONS OF
SOUTHEASTERN MICHIGAN. THIS WILL NEED TO BE MONITORED....NOT
EXPECTING CLOUD BUT CERTAINLY COULD ADD A MOISTURE ADVECTION
COMPONENT THAT MAY BRING SOME HZ TOWARDS MORNING.

//DTW THRESHOLD THREATS...

* NONE

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...CB
LONG TERM....HLO
MARINE.......CB
AVIATION.....CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 181927
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
327 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 316 PM EDT SAT MAY 18 2013

HIGH PRESSURE WILL PROVIDE A LITTLE MORE SUNSHINE...THUS A BIT
WARMER TEMPERATURES FOR SUNDAY. HOWEVER...A STORM SYSTEM DEVELOPING
OVER THE ROCKIES WILL BECOME BETTER ORGANIZED OVER THE
PLAINS...BEFORE MOVING INTO THE GREAT LAKES TO START THE WORK WEEK.
THIS APPROACHING SYSTEM WILL GENERATE THUNDERSTORMS AND MILD
TEMPERATURES...OVER NORTHERN MICHIGAN THROUGH MID WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

ELEVATED WARM FRONT/WARM AIR ADVECTION WING CONTINUES TO LIFT THRU
THE AREA TONIGHT WITH LINGERING MID LEVEL FGEN AND ADIABATIC OMEGA
POSSIBLY PRODUCING A FEW SPRINKLES/LIGHT SHOWER TIP OF THE MITT INTO
EASTERN UPPER.  SKY CONDITIONS RANGING FROM PARTLY CLOUDY SOUTH TO
MOSTLY CLOUDY NORTH.  A MILD NIGHT WITH LOWS FROM THE MID 40S TO
LOWER 50S.

BY FAR THE BEST DAY OF THE WEEKEND ON SUNDAY WITH 850MB THERMAL
RIDGE OF 13-15C BUILDING INTO THE AREA.  MID LEVEL RIDGING WILL
CONTINUE TO DOMINATE OUR WEATHER PICTURE AS DEEPER TROUGH DIGS INTO
THE NORTHERN PLAINS.  SFC DEWPOINTS WILL CONTINUE TO GRADUALLY CREEP
UP AS THE DAY PROGRESSES.  NAM CONTINUING ITS RECENT BIAS OF TOO WET
LOWER LEVELS...WITH CURRENT FCST DEWPOINTS 3-5 DEGF TOO HIGH BASED
ON LATEST OBSERVATIONS.  QUITE WARM ON SUNDAY...WITH HIGH TEMPS
REACHING THE MIDDLE 70S /EASTERN UPPER/ TO LOWER 80S /PORTIONS OF
NORTHERN LOWER/.  WEAK GRADIENT AND WARM TEMPS LEND ITSELF TO LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON HOURS AND WILL COOL TEMPS
CLOSER TO THE COASTS TO ACCOUNT FOR THIS.  EVEN WITH SLIGHTLY LOWER
DWPTS THAN THE NAM FCST SOUNDINGS...MODIFIED SOUNDINGS WITH NEAR DRY
ADIABATIC MIXED LAYER YIELD SEVERAL HUNDRED JOULES OF SKINNY CAPE.
INLAND PENETRATING LAKE BREEZE BOUNDARIES...INCREASING SFC DWPTS AND
SOME INSTABILITY SUPPORT ISOLATED SHOWER MENTION FOR INTERIOR AREAS
DURING THE MID/LATE AFTERNOON.

&&

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 316 PM EDT SAT MAY 18 2013

MID AND UPPER LEVEL PATTERN BECOMING INCREASINGLY BLOCKY WITH
TIME...AT LEAST PARTIALLY DRIVEN BY STRONG NORTH CENTRAL ATLANTIC
CENTERED HIGH PRESSURE RIDGE AXIS. DUAL STRONG SHORTWAVE TROUGHS
DIVING INTO THE PACIFIC NORTHWEST ONLY HELPING THE CAUSE...WITH LEAD
ENERGY EVENTUALLY CARVING OUT A SLOW MOVING UPPER LOW IN THE NATIONS
MIDSECTION EARLY NEXT WORK WEEK...WHILE THE NEXT PIECE DOES THE SAME
ACROSS THE PACIFIC NORTHWEST. SUBSEQUENT CANADIAN PRAIRIE RIDGE
BUILDING BETWEEN THESE FEATURES SETS UP A QUASI-OMEGA BLOCK
SIGNATURE...WITH STRONG ENERGY PROGGED TO DIVE DOWN ITS FRONTSIDE
INTO EAST CENTRAL CANADA ONLY ADDING FURTHER COMPLEXITY TO AN
ALREADY COMPLEX PATTERN. ADD IN A GOOD SUPPLY OF GULF OF MEXICO
MOISTURE AND FGEN DYNAMICS...AND THE PATTERN HAS ALL THE MAKINGS OF
A WET ONE THROUGH AT LEAST THE FIRST HALF OF THIS UPCOMING WEEK.
LATEST WPC 5 AND 7 DAY QUANTITATIVE PRECIPITATION FORECASTS
CONCUR...WITH WIDESPREAD 1 TO 2 INCH AMOUNTS ACROSS OUR AREA...WITH
HEAVIER AMOUNTS TO UPWARDS OF 4 INCHES JUST TO OUR NORTHWEST. AS ONE
CAN IMAGINE GIVEN ABOVE...EXTENDED FORECAST CONCERNS MAINLY CENTER
ON MULTI-PERIOD RAIN SHOWER AND THUNDERSTORM THREATS.

ONE COMPLICATED FORECAST SUNDAY NIGHT INTO MONDAY...WHICH...TO BE
HONEST...DOES NOT SUPPORT A WHOLE LOT OF FORECAST CONFIDENCE.
CENTRAL PLAINS CLOSED LOW BECOMES INCREASINGLY WELL ESTABLISHED...
WITH EXCELLENT FORCED LOW/MID LEVEL CONVERGENCE ZONE SETTING UP
BETWEEN SOUTH FLOW OUT AHEAD OF IT WEAK ENERGY DIVING THROUGH
ONTARIO. STRONG H8 CONVERGENCE AXIS LOOKS TO SLOWLY SAG SOUTH ACROSS
LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY...WITH SURFACE REFLECTION
ESSENTIALLY REMAINING STATIONARY ACROSS THE CLIMATOLOGICALLY FAVORED
TIP OF THE MITT/STRAITS REGION. H8 FRONT LOOKS TO REMAIN VERY
ACTIVE...FOCUSING MUCH OF THE RAIN OFF TO OUR NORTH THROUGH SUNDAY
NIGHT...PERHAPS INTO THE FIRST PART OF MONDAY (HELPED IN PART BY MID
LEVEL RIDGING REMAINING OVERHEAD). CONDITIONS BECOME MUCH MORE
INTERESTING HEADING INTO MONDAY AFTERNOON AND NIGHT AS ENERGY
ROTATING AROUND UPPER LEVEL LOW INTERACTS WITH AN INCREASINGLY
IMPRESSIVE OVERHEAD MOISTURE PLUME AS PWAT VALUES APPROACH AN INCH
AND A HALF. WHILE MODEL DEPICTED SURFACE DEWPOINTS IN THE UPPER
60S/LOWER 70S SEEM AGGRESSIVE...JUXTAPOSITION OF DECENT MOISTURE AND
MID LEVEL SUPPORT SHOULD BE ENOUGH TO KICK OFF ROUNDS OF SHOWERS AND
STORMS...SOME OF WHICH MAY BRING LOCALLY HEAVY RAINFALL. WHILE
SEVERE THREAT NOT COMPLETELY ZERO...BETTER POTENTIAL SHOULD REMAIN
TO OUR SOUTHWEST WITHIN CORRIDOR OF MUCH MORE IMPRESSIVE DEEP LAYER
SHEAR AND BETTER LOW LEVEL INSTABILITY. LATEST DAY 3 SPC SEVERE
GRAPHICS DOES BRING THE SLIGHT RISK RIGHT TO OUR DOORSTEP OVER
SOUTHWEST MICHIGAN. NO DOUBT WORTH KEEPING AN EYE ON THE NEXT FEW
DAYS AS UPSTREAM CONVECTIVE TRENDS WILL LIKELY PLAY HAVOC WITH EXACT
THERMODYNAMIC AND KINEMATIC DETAILS. POTENTIALLY ANOTHER WARM ONE
MONDAY...ESPECIALLY SOUTH OF THE BRIDGE. THERMAL PROGS EASILY
SUPPORT HIGHS BACK INTO THE LOWER 80S...ALTHOUGH CLOUD AND
CONVECTIVE TRENDS MAY PREVENT FULL WARMING FROM BEING REALIZED.

MID-WEEK WEATHER DEPENDENT ON INTERACTION (OR LACK THEREOF) BETWEEN
APPROACHING MID LEVEL LOW AND STRONGER ENERGY DIVING SOUTH OUT OF
CANADA. THE FORMER CONTINUES TO SUPPLY PLENTY OF MOISTURE AND
DYNAMICS...WHILE THE LATTER ATTEMPTS TO DRIVE BEST FGEN/BAROCLINIC
ZONE FURTHER SOUTH WITH TIME. DEEP LAYER CONVERGENCE AND MOISTURE
SUPPORTS PLENTY OF RAIN POTENTIAL...WITH PLACEMENT OF THE HEAVIEST
AND STEADIEST RAINFALL TIED TO ABOVE INTERACTION. 00Z ECMWF/GEM
OFFER A RATHER WET SCENARIO...KEEPING CORRIDOR OF DEEP LAYER
CONVERGENCE OVERHEAD RIGHT THROUGH THURSDAY. GFS A TOUCH MORE
AGGRESSIVE DRIVING THIS CORRIDOR SOUTH...ALTHOUGH IT TOO SUGGESTS
LINGERING RAINS INTO THURSDAY (JUST NOT AS HEAVY). HARD TO GET A
FEEL FOR WHICH IS MORE CORRECT...WITH THE END RESULT LIKELY A MIDDLE
GROUND BETWEEN THE TWO. INHERITED FORECAST KEEPS RAINS LINGERING
THROUGH THURSDAY...AS WILL THIS FORECAST. SEVERE THREAT SHOULD ONLY
SAG SOUTH WITH TIME AS LOW LEVEL BAROCLINIC ZONE DOES THE SAME. THAT
SAID...PROXIMITY OF IT AND SOME EVIDENCE FOR IT TO RETURN BRIEFLY
NORTH LATER WEDNESDAY...AS MAIN WESTERN ENERGY APPROACHES...
DEFINITELY RAISES SOME CONCERN.

START OF MEMORIAL DAY WEEKEND LOOKING COOL AND DRY AS CANADIAN HIGH
PRESSURE BUILDS OVERHEAD. HIGHS FRIDAY AND SATURDAY LOOK TO ONLY
REACH INTO 60S (UPPER 50S ACROSS EASTERN UPPER?)...WHICH WOULD BE AT
LEAST A FEW DEGREES BELOW NORMAL. PATTERN RECOGNITION SUPPORTS THE
POTENTIAL FOR SOME RATHER CHILLY OVERNIGHT READINGS THURSDAY THROUGH
SATURDAY. SOMEWHAT DISCONCERTING TO SEE LATEST CLIMO INFLUENCED
ECMWF MOS SHOWING COLDER LOCATIONS DIPPING INTO THE MIDDLE AND UPPER
30S EARLY FRIDAY MORNING...AND WIDESPREAD LOWER AND MIDDLE 30 DEGREE
READINGS SATURDAY MORNING. OTHER GUIDANCE NOT QUITE AS COLD...BUT
DEFINITELY SOMETHING TO MONITOR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM EDT SAT MAY 18 2013

VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD.  WARM FRONT WILL
MOVE NORTH OF THE AREA THROUGH TONIGHT WITH MID CLOUDS AND
A FEW SPRINKLES.  SCATTERED DIURNAL CU FIELDS ON SUNDAY WITH BASES
FROM 5-6K.  LIGHT WINDS THROUGHOUT...WITH LAKE BREEZE DEVELOPMENT
CLOSER TO THE COASTS ON SUNDAY.


&&

.MARINE...
ISSUED AT 316 PM EDT SAT MAY 18 2013

GRADIENT WILL REMAIN RELATIVELY WEAK OVER THE NEXT FEW DAYS AS HIGH
PRESSURE SLOWLY DEPARTS TO THE EAST. AS LOW PRESSURE DRAWS CLOSER
TO THE AREA TUESDAY/WEDNESDAY...WINDS WILL INCREASE AND SMALL
CRAFT CONDITIONS ARE POSSIBLE.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...MB
AVIATION...JK
MARINE...JK

000
FXUS63 KGRR 181911
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
311 PM EDT SAT MAY 18 2013

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/FIREWEATHER/HYDRO/MARINE

.SYNOPSIS...
ISSUED AT 216 PM EDT SAT MAY 18 2013

LOW PRESSURE DEVELOPING IN COLORADO WILL TRACK SLOWLY EAST OVER
THE NEXT COUPLE OF DAYS. SOUTHEAST WINDS AHEAD OF THIS SYSTEM WILL
DRAW WARMER AND INCREASINGLY MOIST AIR INTO THE GREAT LAKES
REGION.  AS A RESULT NUMEROUS SHOWERS AND THUNDERSTORMS ARE FORECASTED
TO ARRIVE BY MONDAY. THIS UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE MIDDLE PART OF THE WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 216 PM EDT SAT MAY 18 2013

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THUNDERSTORM
AND SEVERE WEATHER POTENTIAL ON MONDAY.

THE COMBINATION OF UPPER LEVEL DIVERGENCE...INCREASING DEEP LAYER
SHEAR...ARRIVAL OF GULF MOISTURE AND BUILDING CAPE SUPPORTS AN
INCREASED RISK FOR ORGANIZED CONVECTION MONDAY INTO MONDAY NIGHT.
MID LEVEL LAPSE RATES STEEPEN TO 7.5 TO 8 DEG C/KM.  A 20 TO 30
KNOT LOW LEVEL JET SETS UP JUST SOUTH OF THE MI BORDER MONDAY AND
STAYS THERE THROUGH MON NIGHT. THIS SHOULD FOCUS THE CONVECTION IN
LOWER MI THROUGH THAT PERIOD. THE SURFACE WARM FRONT WILL BE
LIFTING THROUGH AT THAT TIME WHICH WILL ALSO HELP TO PROVIDE A
FOCUS FOR THE CONVECTION. MODELS ARE IN DECENT AGREEMENT ON THIS
SCENARIO. SO WILL FEATURE NUMEROUS SHOWERS AND THUNDERSTORMS FOR
THIS PERIOD. I SUSPECT WE WILL SEE MORE THAN ON ROUND OF
CONVECTION IN THIS TIMEFRAME. RAINFALL COULD BE HEAVY AND REPEAT
OVER THE SAME REGION GIVEN THE FRONTAL ZONE WILL BECOME NEARLY
PARALLEL TO THE MID TO UPPER LEVEL FLOW.

I CONSIDERED ADDING A SMALL CHANCE FOR A STORM SUNDAY AFTERNOON
CLOSER TO THE LAKESHORE. A LAKE BREEZE WILL TRY TO DEVELOP. WHILE
SOME INSTABILITY WILL BE PRESENT...THE MOISTURE IS STILL SOMEWHAT
LIMITED. THERE IS A WEAK CAP/WARM LAYER NOTED IN FORECAST
SOUNDINGS UP AROUND 650 MB AS WELL. SO WILL KEEP IT DRY. IT WILL
BE A WARM DAY WITH MOST LOCATIONS TOPPING OUT IN THE LOW TO MID
80S. I DID WARM TEMPERATURES UP ALONG THE SHORELINE AS THE FLOW
WILL FEATURE AN OFFSHORE COMPONENT TO START THE DAY.



.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 216 PM EDT SAT MAY 18 2013

AN ACTIVE WEATHER PATTERN WILL BE UNDERWAY TUESDAY AS A SLOW MOVING
LOW MIGRATES FROM THE PLAINS EASTWARD. A STATIONARY FRONT EXTENDING
EASTWARD FROM THE LOW WILL BE A FOCUS FOR SHOWERS AND THUNDERSTORMS
THROUGH WEDNESDAY. PWAT VALUES NEAR 1.75 INCHES SUGGESTS A HEAVY
RAIN POTENTIAL. MODELS CERTAINLY SHOW QUITE A BIT OF INSTABILITY
WITH LI/S NEAR -8C AND MLCAPE AROUND 2500 J/KG SHEAR VALUES IN THE
45-50KT RANGE POINT TOWARD A SVR POTENTIAL TOO. NO ONE TIME PERIOD
LOOKS MORE FAVORABLE THAN ANOTHER. OF COURSE AFTERNOON INSTABILITY
MAY BE KEY. HOWEVER WITH THE FRONT NEARBY...ELEVATED STORMS COULD BE
POSSIBLE TOO AND BE LESS INFLUENCED BY DAYTIME HEATING. THE LLJ
ISN/T ALL THAT IMPRESSIVE WITH THE SYSTEM BUT MOISTURE TRANSPORT
LOOKS ADEQUATE FOR STORM INITIATION.

AS THE LOW MOVES OVERHEAD WEDNESDAY NIGHT AND THURSDAY WE SHOULD SEE
THUNDERSTORM CHANCES DECREASE IN FAVOR OF SHOWERS. A DRYING TREND
WILL GREET THE BEGINNING OF THE MEMORIAL DAY WEEKEND RESULTING IN PT
CLDY SKIES WITH HIGHS IN THE MID 60S AND LOWS IN THE MID 40S.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1241 PM EDT SAT MAY 18 2013

VFR CIGS EXPECTED THROUGH THE PERIOD. HOWEVER AS DEWPOINTS
INCREASE LATE TONIGHT WE MAY SEE SOME FOG DEVELOP WITH VSBYS
FALLING TO 4-5SM BR PRIOR TO SUNRISE.


&&

.MARINE...
ISSUED AT 216 PM EDT SAT MAY 18 2013

WATER TEMPERATURES WILL BE ON THE RISE INTO EARLY NEXT. WHILE WE
HAVE OFFSHORE FLOW...IT IS NOT THAT STRONG. THE FLOW VEERS TO THE
SOUTH AND THE AIR TEMPERATURE WARMS. ALSO MOISTURE WILL BE ON THE INCREASE.
TYPICALLY IN THESE SETUPS WATER TEMPERATURES CLIMB RATHER QUICKLY. WILL
NEED TO MONITOR THE FOG SETUP AS SURFACE DEWPOINTS WILL CLIMB INTO
THE 60S. THE STABLE COLDER WATER TEMPERATURES GENERALLY IN THE LOW 40S WILL
LIMIT THE WAVE DEVELOPMENT.

&&

.FIRE WEATHER...
ISSUED AT 216 PM EDT SAT MAY 18 2013
WARM AND DRY INTO SUNDAY. MOISTURE WILL BE ON THE INCREASE AND
THAT WILL KEEP HUMIDITY LEVELS UP. WIND VALUES WILL BE RELATIVELY
LIGHT DUE TO THE WEAKER PRESSURE GRADIENT.


&&

.HYDROLOGY...
ISSUED AT 216 PM EDT SAT MAY 18 2013

GULF MOISTURE WILL BE STREAMING INTO LOWER MICHIGAN THROUGH THE
MIDDLE PART OF THE WEEK. THIS WILL INCREASE THE RISK FOR HEAVIER
RAIN. THE MAIN TIMEFRAME FOR POTENTIAL HEAVY RAIN WILL EXIST
BETWEEN MONDAY AND WEDNESDAY.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...93
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KMQT 181747
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
147 PM EDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SAT MAY 18 2013

IN THE LARGE SCALE...TROUGH OVER THE ROCKIES WILL SLIDE ONTO THE
HIGH PLAINS BY SUNDAY MORNING ALLOWING RIDGING TO SLIGHTLY BUILD
OVER THE WESTERN GREAT LAKES. ALTHOUGH SFC-H85 TROUGHING OVER THE
DAKOTAS DOES NOT MOVE MUCH TO THE EAST...IT IS ENOUGH TO INCREASE
LOW-LEVEL SOUTHERLY FLOW ACROSS THE UPPER GREAT LAKES. PATTERN IS
SERVING TO INCREASE MOISTURE /PWATS 1.15 OF 1.31 INCHES AT GRB AND
MPX OR AROUND 200 PCT OF NORMAL/ IN WAKE OF DRY SFC HIGH THAT HAS
BEEN ESTABLISHED OVER THE AREA FOR MOST OF THIS WEEK. REGIONAL RADAR
SHOWS DECAYING ECHOES OVER NORTHERN WISCONSIN. MUCH MORE ORGANIZED
AREA OF SHRA/TSRA HAVE DEVELOPED SINCE 03Z FROM CENTRAL MINNESOTA
INTO WEST CENTRAL WISCONSIN ALONG H85 WARM FRONT/GRADIENT OF H85
THETA-E. ADDITIONAL AREA OF SHRA/TSRA SPREADING ACROSS NORTHEAST
SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA NEAR CONVECTIVE INDUCED
SHORTAVE/H7-H3 DIFFERENTIAL PVA AND CLOSE TO H7 MOISTURE TRANSPORT.
JUST RECENTLY ANOTHER LARGE CLUSTER OF SHRA/TSRA HAVE FORMED IN THE
WARM AIR ADVECTION REGIME BTWN THESE TWO INITIAL AREAS OF PRECIP.

GIVEN EXTENT OF SHRA/TSRA UPSTREAM OF CWA THIS MORNING AND SINCE
H85-H7 MOISTURE ADVECTION IS FORECAST WEST TO EAST ACROSS CWA
THROUGH THE DAY...INCREASED POPS FOR MOST OF THE WEST AND NORTHERN
CWA AS AT LEAST MULTIPLE REMNANTS OF THIS CONVECTION SHOULD MAKE IT
INTO UPR MICHIGAN. LEANED ON THE NCEP WRF MODELS AND RECENT HRRR AND
EXTRAPOLATION OF LATEST HRRR TO CREATE POPS. RESULT IS LIKELY POPS
MOST OF THE DAY OVER THE WEST HALF...WITH SMALLER CHANCES FARTHER
EAST AS THE RAIN RUNS INTO THE VERY DRY AIRMASS ASSOCIATED WITH SFC
HIGH TO THE EAST. MAJORITY OF TSRA THUS FAR STAYING OVER NORTHERN
MINNESOTA ON GRADIENT OF 1-6KM MUCAPE RESERVOIR. HINT IN MODELS
THAT EASTERN EDGE OF INSTABILITY GRADIENT SLIDES TOWARD WESTERN UPR
MICHIGAN SO HAVE INCLUDED SLIGHT CHANCES FOR TSRA. CONVECTION IS
ELEVATED AND MID-LEVEL LAPSE RATES BARELY GET ABOVE 6C/KM. MAIN
ISSUE WILL BE HEAVY DOWNPOURS AND LIGHTNING STRIKES. TEMPS TODAY
A BIT TOUGH TO FIGURE OUT. EAST GRADIENT WINDS SHOULD KEEP KEWEENAW
CHILLY WITH READINGS STAYING BLO 50 DEGREES. MIXING TO H9 IS PROBABLY
IT WHERE CLOUDS/RAIN PERSIST MOST OF THE DAY. THIS SUPPORTS MAJORITY
OF CWA SEEING HIGHS IN THE 60S...EVENTUALLY...ONCE THE STEADIER RAIN
TAPERS OFF THIS AFTN. SFC WARM FRONT MAY TRY TO POKE INTO FAR SW CWA
LATE IN THE DAY. IF THIS OCCURS AND PRECIP TAPERS OFF/ENDS...THEN
THERE IS POTENTIAL FOR HIGHS TO PUSH WELL INTO THE 70S FROM IWD TO
IMT.

H85 FRONT LIFTS NORTH OF MOST CWA THIS EVENING. KEWEENAW STILL CLOSE
ENOUGH TO FRONT AND WITHIN THE RIBBON OF PERSISTENT MOISTURE
ADVECTION SO KEPT SHRA/ISOLD TSRA THERE THROUGH THE EVENING. DRYING
TREND TAKES HOLD OVERNIGHT AS THE FOCUS FOR SHRA/TSRA...H85 WARM
FRONT AND THETA-E GRADIENT...LIFTS WELL TO NORTH OF UPR MICHIGAN.
KEPT SMALL POPS IN AT ISLE ROYALE LATE TONIGHT THOUGH. TEMPS MOSTLY
IN THE 40S EAST WITH FLOW OFF LK MICHIGAN. LESS MODIFIED AIR FARTHER
WEST ALLOWS MINS TO ONLY FALL INTO THE LOW-MID 50S ALONG LK SUPERIOR
AROUND IWD TO ONTONAGON AND EAST TO BARAGA/L`ANSE AND MARQUETTE
AREAS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 510 AM EDT SAT MAY 18 2013

NAM SHOWS THE 500 MB RIDGE OVER THE EASTERN U.S. 12Z SUN WITH
TROUGHING IN THE ROCKIES. THE TROUGH MOVES EAST ON SUNDAY AND PUSHES
THE RIDGE INTO THE LOWER GREAT LAKES 12Z MON WHERE THE MOVEMENT
EASTWARD STOPS THROUGH 12Z TUE. NAM HAS SOME DEEPER MOISTURE AND
850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA 12Z SUN ONWARD. GFS
SHOWS ABOUT THE SAME THING AS WELL.

THIS PERIOD LOOKS PRETTY WET STARTING WITH SUN AFTERNOON THROUGH MON
NIGHT. WITH SLOW MOVEMENT OF SYSTEM INTO AND THROUGH THE AREA AND
ALSO A WARM FRONT NEAR AND TO THE SOUTH OF THE AREA...THIS SETS UP
THE CWA FOR A WIDESPREAD AND LONG LIVED RAIN EVENT WITH SOME HEAVY
RAIN POSSIBLE. AM FORECASTING ANYWHERE FROM .67 INCH OF QPF OVER THE
SOUTH...TO 1.15 INCHES OVER THE EAST TO OVER 2 INCHES OF RAIN IN THE
FAR WEST NEAR IRONWOOD FROM SUNDAY AFTERNOON THROUGH MONDAY NIGHT
AND THIS DOES NOT SEEM UNREASONABLE WITH PLENTY OF MOISTURE TO THE
SOUTH OF THE AREA AND SLOW SYSTEM MOVEMENT. FOR THIS REASON...BUMPED
POPS UP A BIT TO LIKELY TO CATEGORICAL FOR MOST OF THE CWA THROUGH
THEN. SHOULD SEE SOME SUNSHINE ON SUNDAY. MADE A FEW ADJUSTMENTS TO
TEMPERATURES BASED ON LAKE BREEZES AND WIND DIRECTIONS AND LOWERED
THEM A BIT NEAR THE GREAT LAKES SHORELINES. OTHER THAN THAT...NO
REAL BIG CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW AND TROUGH
IN THE NORTHERN AND CENTRAL PLAINS 12Z TUE WHICH MOVE LITTLE INTO
12Z WED. BY 12Z THU...THE TROUGH AND LOW GET PUSHED A BIT FURTHER
EAST TO THE UPPER GREAT LAKES REGION. THE TROUGH AND LOW MOVE
THROUGH BY 12Z FRI WITH RIDGING BUILDING INTO THE PLAINS LATE ON
FRI. SYSTEM WILL BE SLOW TO MOVE THROUGH THE AREA...SO A COUPLE OF
DAYS OF WIDESPREAD RAIN ARE NOT OUT OF THE QUESTION ALONG WITH
COOLER TEMPERATURES WITH GRADUAL SOUTHWARD MOVEMENT OF THE SYSTEM
AWAY FROM THE AREA. THU INTO FRI...THINGS START TO DRY OUT WITH A
COLD FRONT WELL SOUTH OF THE AREA. TEMPERATURES SLIP TO SLIGHTLY
BELOW NORMAL THIS PERIOD. POPS WILL BE HIGHEST IN THE SOUTH CLOSER
TO A WARM FRONT.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT MAY 18 2013

A WARM FNT MOVING IN FM THE SOUTH WILL BRING SOME -SHRA/MVFR CIGS
/LIFR CIGS AT CMX WITH UPSLOPE FLOW/...MAINLY AT IWD/CMX WHERE LLVL
WARM/MOIST ADVCTN WL BE MOST PRONOUNCED. MOIST UPSLOPE FLOW OFF LK
SUPERIOR MAY RESULT IN IFR CONDITIONS INTO THIS EVENING. FOLLOWING
THE WARM FROPA TONIGHT...EXPECT WSHFT TO THE S WITH RETURN TO
PREDOMINANT VFR WX. THE ONLY EXCEPTION WL BE AT CMX...WHERE
PERSISTENT UPSLOPE ESE WIND AND MOISTER LLVL AIR WL RESULT IN
LINGERING MVFR CONDITIONS THROUGH MUCH OF THE NIGHT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...TITUS
MARINE...07

000
FXUS63 KDTX 181736
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
136 PM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

PERSISTENT FLOW OFF OF THE CENTRAL GREAT LAKES AGGREGATE IS
ALLOWING SURFACE HIGH PRESSURE TO HOLD ON ACROSS SOUTHEASTERN
MICHIGAN. DRY AIR IN THE LOWEST 6 KFT AGL HAS BEEN THE STORY OF
RECENT DAYS AND WILL NOT BE GOING ANYWHERE ANYTIME SOON. MAIN
SHEARING DEFORMATION AXIS THAT IS IN PLACE OVER CENTRAL LOWER
MICHIGAN...SAGINAW BAY AND THUMB WILL LIFT NORTHWARD TODAY IN
RESPONSE TO BUILDING UPPER LEVEL HEIGHTS/LONGWAVE RIDGE AXIS.
THEREFORE...EXPECT VFR CONDITIONS WITH PERHAPS SOME MESSY MID TO
HIGH CLOUD AT TIMES. WILL BE WATCHING SOME LOWER LEVEL MOISTURE
LIFT ANTICYCLONICALLY OUT OF OHIO TONIGHT AND INTO PORTIONS OF
SOUTHEASTERN MICHIGAN. THIS WILL NEED TO BE MONITORED....NOT
EXPECTING CLOUD BUT CERTAINLY COULD ADD A MOISTURE ADVECTION
COMPONENT THAT MAY BRING SOME HZ TOWARDS MORNING.

//DTW THRESHOLD THREATS...

* NONE

&&

.PREV DISCUSSION...ISSUED 339 AM EDT SAT MAY 18 2013

SHORT TERM...TODAY AND TONIGHT

MID/UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO THE REGION TODAY
WHILE WE REMAIN ON THE WESTERN EXTENT OF A DOME OF HIGH PRESSURE AT
THE SFC CENTERED OVER EASTERN CANADA. EASTERLY WINDS WILL PERSIST
THROUGH TONIGHT DUE TO THE SFC HIGH. THE CONTINUED FEED OF DRY
CONTINENTAL AIR WILL KEEP DEWPOINTS IN THE 40S ONCE AGAIN. MODEL
SOUNDINGS IN FAIRLY GOOD AGREEMENT WITH THE 00Z DTX SOUNDING WITH
THE DEPTH OF DRY AIR IN THE BOUNDARY LAYER CURRENTLY AROUND 9KFT.
THE 700MB WARM FRONT LIFTED THROUGH FRIDAY AFTERNOON AND MODELS SHOW
THE WEAKER 925 MB FRONT WILL FOLLOW NORTHWARD THROUGH TODAY. HARD TO
FIND ANY ADDITIONAL SUPPORT TO HELP THIS KICK OFF ANY SHOWERS THIS
AFTERNOON. MODELS KEEP MOST OF THE SHOWERS OVER THE OHIO VALLEY
WHERE SFC MOISTURE IS MUCH HIGHER. THE LIKELY RESULT WILL END UP
BEING A LOWERING OF THE CLOUD DECK TO AROUND 6-7KFT. WEAK WAA WILL
ALLOW TEMPS TO REBOUND A FEW MORE DEGREES TODAY INTO THE MID/UPPER
70S WITH COOLER TEMPS FOR AREAS IN THE LAKE SHADOW.

LONG TERM...SUNDAY THROUGH FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
ON SUNDAY. ALTHOUGH A SURFACE WARM FRONT WILL LIFT NORTH THROUGH THE
CWA EARLY ON SUNDAY...DRY CONDITIONS ARE EXPECTED TO CONTINUE
DESPITE MUCAPE VALUES APPROACHING 1000 J/KG DURING THE AFTERNOON
HOURS GIVEN THE VERY DRY AND IN PLACE AND STABILIZING EFFECT OF
DOWNWARD MOTION FROM THE UPPER LEVEL RIDGE. THE PASSAGE OF THE WARM
FRONT WILL BRING WARMER AIR TO THE REGION...WITH DAYTIME HIGHS
AROUND THE 80 DEGREE MARK AWAY FROM LAKE HURON.

WARM AIR WILL CONTINUE TO STREAM IN BEHIND THE WARM FRONT EARLY IN
THE WORK WEEK AS SOUTHERLY WINDS BRING A MARKED INCREASE IN MOISTURE
ACROSS SOUTHERN MICHIGAN. THE INCREASED MOISTURE AS WELL AS THE
SHIFT EAST IN THE UPPER LEVEL RIDGE WILL BRING AN INCREASE IN RAIN
CHANCES TO SOUTHEAST MICHIGAN AS THE WEEK PROGRESSES. ALTHOUGH AN
UPPER LEVEL LOW WILL SIT OFF TO THE WEST DURING THE EARLY PART OF
THE WEEK...SEVERAL EMBEDDED SHORTWAVES WILL TAKE ADVANTAGE OF THE
INCREASED INSTABILITY OF 1000 TO 2000 J/KG MONDAY AND TUESDAY. THE
UPPER LEVEL DYNAMICS AND INSTABILITY WILL BRING THE POSSIBILITY FOR
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS TO THE AREA. DESPITE THE
DECENT CAPE VALUES...SHEAR WILL BE VERY WEAK IN THE LOW LEVELS WITH
A RATHER UNIMPRESSIVE HODOGRAPH AND MEAGER HELICITY VALUES. MONDAY
LOOKS TO BE THE WARMEST DAY OF THE UPCOMING WEEK WITH HIGH
TEMPERATURES GETTING INTO THE LOWER TO MIDDLE 80S ACROSS MUCH OF THE
CWA.

ALTHOUGH MODEL DIFFERENCES STILL EXIST...THERE APPEARS TO BE MORE
AGREEMENT IN HANDLING THE CUT OFF LOW OUT TO THE WEST AS IT
PROGRESSES EAST DURING THE MIDDLE OF THE WEEK. THE GFS AND ECMWF
SOLUTIONS MERGE THIS LOW WITH THE NORTHERN STREAM LOW OVER HUDSON
BAY...ABSORBING THE LOW AS A POSITIVELY TILTED TROUGH TRACKING
THROUGH THE CENTRAL GREAT LAKES REGION. ALTHOUGH THUNDERSTORMS ARE
STILL POSSIBLE DURING THE MIDDLE OF THE WEEK...THE BEST INSTABILITY
WILL BE WELL TO THE SOUTH. HOWEVER THE SYSTEM WILL HAVE ENOUGH
MOISTURE TO PRODUCE SOME HEAVY RAIN SHOWERS DURING THE MIDDLE OF THE
WEEK AS THE SURFACE LOW TRACKS THROUGH THE SOUTHERN GREAT LAKES
REGION.

CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE LOW LATE IN THE
WEEK...BRINGING DRY CONDITIONS AND MUCH COOLER DAYTIME HIGHS IN THE
60S TO SOUTHEAST MICHIGAN.

MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....CB
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 181701
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
101 PM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 317 AM EDT SAT MAY 18 2013

HIGH PRESSURE WILL EXIT TO THE EAST...ALLOWING FOR WARMER CONDITIONS
ALONG WITH A CHANCE FOR SHOWERS OVER THE WEEKEND. A STORM SYSTEM
CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO THE PLAINS
TODAY...AND INTO THE GREAT LAKES TO START THE WORK WEEK. THIS WILL
GENERATE SHOWERS AND THUNDERSTORMS OVER NORTHERN MICHIGAN BEGINNING
MONDAY AND CONTINUING THROUGH MIDWEEK.

&&

.UPDATE...
ISSUED AT 1244 PM EDT SAT MAY 18 2013

THICKEST MID/HIGH CLOUD SHIELD GRADUALLY LIFTING TO THE NORTHEAST
WITH ELEVATED WARM FRONT/MID LEVEL ADIABATIC OMEGA.  STILL A FEW
SPRINKLES/LIGHT RAIN SHOWERS...BUT PCPN COVERAGE HAS BEEN
DIMINISHING OVER THE PAST FEW HOURS. WILL MAKE A FEW ADJUSTMENTS
TO SKY COVER...WITH INCREASING SUNSHINE FROM SOUTHWEST TO
NORTHEAST AS THE AFTERNOON PROGRESSES. STILL MAY BE DIFFICULT TO
LOSE THE CLOUDS FROM THE TIP OF THE MITT INTO EASTERN UPPER.
WARMEST TEMPS /MID 70S/ TO THE SOUTHWEST WHERE SUNSHINE WILL BE
GREATEST.

UPDATE ISSUED AT 948 AM EDT SAT MAY 18 2013

ELEVATED WARM FRONT GRADUALLY SLIDING TO THE NORTH THIS MORNING
WITH DEEPEST FORCING/MOISTURE REMAINING WEST OF OUR AREA. DESPITE
LITTLE MOISTURE BELOW 800MB ACROSS NORTHERN MICHIGAN...STILL
ENOUGH FORCING TO CREATE PATCHY LIGHT RAIN AND SPRINKLES /SPOTTER
REPORTS UP TO 0.06 INCHES OF RAIN/. FORCING WILL DIMINISH OVER THE
NEXT SEVERAL HOURS AS EVERYTHING GRADUALLY PUSHES TO THE NORTH.
EXPECT CURRENT AREA OF LIGHT PCPN TO GRADUALLY DIMINISH THROUGH
EARLY AFTERNOON AS IT PUSHES INTO EASTERN UPPER/TIP OF THE MITT.
LIKELY STILL SOME SPRINKLES OVER PORTIONS OF NORTHERN LOWER INTO
THE AFTERNOON WITH LINGERING FORCING AND PLENTY OF MID CLOUD.
PREVAILING CLOUDY SKIES TODAY...WITH SOME BREAKS LIKELY OVER
SRN/SW AREAS. LOWERED TEMPS IN MANY AREAS THIS AFTERNOON...ESPECIALLY
GAYLORD NORTHWARD WITH MORE CLOUDS AND LIGHT PCPN.

UPDATE ISSUED AT 650 AM EDT SAT MAY 18 2013

ISOLD LIGHT SHOWERS CONTINUE TO IMPACT THE SW HALF OF OUR CWA
EARLY THIS MORNING AS LIMITED LOW/MID LEVEL MOISTURE LIFT INTO NRN
MICHIGAN NORTH OF A WARM FRONT. THUNDERSTORMS CONTINUE TO FIRE
WELL UPSTREAM OVER MINNESOTA IN THE VCNTY OF AN 850 MB THETA E
RIDGE AND INSTABILITY AXIS. LATEST NAM STILL POINTS TOWARD THIS
INSTABILITY AND DEEPER MOISTURE REMAINING UPSTREAM OF OUR CWA THRU
THE DAY...WITH ONLY SOME ISOLATED SHOWERS AND MAINLY CLOUDY SKIES
EXPECTED FOR US TODAY. THESE ISOLD SHOWERS WILL GRADUALLY LIFT
NORTHWARD INTO THE REST OF OUR CWA THRU THE DAY AS THE WARM FRONT
EDGES CLOSER. NO CHANGES ARE NEEDED TO THE TIMING OF WX/POPS FOR
NOW.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 317 AM EDT SAT MAY 18 2013

ON THE LATEST SURFACE WEATHER MAP...1025 MB HIGH PRESSURE WAS
CENTERED OVER SOUTHEAST ONTARIO WITH 1002 MB LOW PRESSURE ALONG THE
FRONT RANGE OF THE CENTRAL ROCKIES. APX AND SURROUNDING RADARS
SHOWED A FEW LIGHT RAIN SHOWERS SPRINKLED ACROSS PORTIONS OF NORTH
CENTRAL LOWER MICHIGAN. THE MAIN SHORT TERM FORECAST CONCERNS CENTER
AROUND POPS AND HIGH TEMPERATURES TODAY.

TODAY INTO TONIGHT...MORE OF THE SAME WITH SUBTLE WARM FRONT AND
INCREASING THETA-E RIDGING (MOISTURE) ADVECTING INTO THE REGION FROM
THE SOUTHWEST. THE MAIN FORCING/BETTER MOISTURE REMAIN TO OUR WEST
CLOSER TO PARENT UPPER LOW SPINNING ITS WHEELS ACROSS THE ROCKIES.
LOOKING AT MODEL CROSS SECTIONS...LOWER LEVELS REMAIN RATHER DRY
WITH ABUNDANT MID LEVEL MOISTURE (FROM ABOUT 850 TO JUST BELOW 500
MB). SO EXPECT MOSTLY CLOUDY SKIES WITH ISOLATED LIGHT RAIN SHOWERS
MARCHING FROM SOUTHWEST TO NORTHEAST THROUGH THE DAY. MAINLY DRY
TONIGHT WITH PERHAPS JUST A FEW LEFTOVER ISOLATED RAIN SHOWERS
ACROSS THE FAR NORTH. TEMPERATURES ARE A BIT TRICKY TODAY WITH
ABUNDANT CLOUD COVER AND WEAK WARM ADVECTION. HIGHS EXPECTED TO
RANGE FROM THE MIDDLE 60S NORTH TO THE MIDDLE 70S SOUTH. LOWS
TONIGHT RANGING FROM THE MIDDLE 40S TO LOWER 50S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM EDT SAT MAY 18 2013

SUNDAY...WILL BE THE BEST WEATHER DAY OF THE WEEKEND. ERN EDGE OF A
WARM FRONT WILL LIFT NORTHWARD INTO UPPER MICHIGAN. SOUTHERLY FLOW
SOUTH OF THE WARM FRONT WILL BOOST TEMPS INTO THE LOW TO MID 70S
ACROSS ERN UPR MICHIGAN AND INTO THE UPPER 70S AND LOWER 80S ACROSS
NRN LWR MICHIGAN. STILL APPEARS SUNDAY WILL BE DRY WITH PARTLY SUNNY
SKIES...AND WILL LIKELY SERVE AS OUR LAST COMPLETELY DRY DAY FOR
MOST OF NEXT WORK WEEK (MORE ON THIS BELOW). AT THIS POINT...SUNDAY
EVENING SHOULD REMAIN DRY...BUT PRECIP CHANCES WILL BEGIN TO
INCREASE ACROSS OUR WRN CWA LATE SUNDAY NIGHT AS AN INITIAL SHORT
WAVE ACCOMPANIED BY BETTER MOISTURE ARRIVE TOWARD DAYBREAK.

MONDAY THRU WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE
FROM WEST TO EAST ON MONDAY AS THE WARM FRONT SAGS SOUTHWARD INTO
NRN LWR MICHIGAN. DEVELOPING LOW PRESSURE IN THE PLAINS WILL BEGIN
TO TAP INTO GULF MOISTURE...ADVECTING IT NORTHWARD THRU THE LOWER
AND MID MISSISSIPPI VALLEY AND INTO THE WRN GREAT LAKES. AS THIS
DEEPER MOISTURE BEGINS TO INTERACT WITH THE WARM FRONT AND A SERIES
OF SHORT WAVES RIDING NE THRU MICHIGAN AHEAD OF THE DEEPENING UPPER
LOWER...WAVES OF SHOWERS AND STORMS WILL REMAIN THE RULE BEGINNING
MONDAY AND CONTINUING THRU WEDNESDAY NIGHT. SURFACE AND CLOSED UPPER
LOW BECOME VERTICALLY STACKED...THUS MAKING VERY SLOW EASTWARD
PROGRESS OVER THIS TIME PERIOD...AND THEREFORE KEEPING OUR WEATHER
UNSETTLED THRU MID WEEK (AT LEAST). WARM TEMPS WILL HOLD OVER THE
REGION ON MONDAY BEFORE THE WARM FRONT SAGS SOUTH ON TUESDAY AND
WEDNESDAY. HIGH TEMPS ON MONDAY WILL RANGE FROM AROUND 70 DEGREES
ACROSS ERN UPR MICHIGAN NORTH OF THE WARM FRONT TO THE MID 70S TO
LOWER 80S SOUTH OF THE WARM FRONT. HIGH TEMPS WILL ONLY REACH INTO
THE 60S BOTH TUESDAY AND WEDNESDAY AS THE WARM FRONT CONTINUES TO
DROP SOUTH OF OUR CWA.

THURSDAY AND FRIDAY...SURFACE AND UPPER LOW CENTERS WILL SLOWLY
SLIDE THRU LWR MICHIGAN ON THURSDAY...EXITING EAST TOWARD NEW
ENGLAND BY FRIDAY. SOME SHOWERS WILL LINGER ACROSS OUR CWA THURSDAY
AROUND AND JUST NORTH OF THE SURFACE LOW CENTER...BUT SHOULD COME TO
AN END BY FRIDAY AS DRIER AIR FILTERS INTO THE REGION BEHIND THE
DEPARTING LOW. THE COLDER AIR BEHIND THIS SYSTEM WILL NOT ARRIVE
UNTIL SATURDAY. NEUTRAL TEMP ADVECTION WILL LEND TO HIGH TEMPS
REMAINING IN THE 60S FOR BOTH THURSDAY AND FRIDAY. A FIRST LOOK AT
NEXT WEEKEND LOOKS DRY BUT POTENTIALLY COOLER THAN NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM EDT SAT MAY 18 2013

VFR CONDITIONS EXPECTED THROUGHOUT THE PERIOD.  WARM FRONT WILL
MOVE NORTH OF THE AREA THROUGH TONIGHT WITH MID CLOUDS AND
A FEW SPRINKLES.  SCATTERED DIURNAL CU FIELDS ON SUNDAY WITH BASES
FROM 5-6K.  LIGHT WINDS THROUGHOUT...WITH LAKE BREEZE DEVELOPMENT
CLOSER TO THE COASTS ON SUNDAY.

&&

.MARINE...
ISSUED AT 317 AM EDT SAT MAY 18 2013

SOUTH-SOUTHEAST FLOW SLOWLY INCREASES TODAY THROUGH SUNDAY...AND  A
HANDFUL OF SMALL CRAFT ADVISORIES MAY BE NEEDED AT SOME POINT LATER
IN THE WEEKEND.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JK
SYNOPSIS...MR
SHORT TERM...AS
LONG TERM...MR
AVIATION...JK
MARINE...AS

000
FXUS63 KGRR 181643
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1243 PM EDT SAT MAY 18 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FAIR AND MILD WEATHER IS ANTICIPATED THIS WEEKEND. A LOW PRESSURE
SYSTEM OVER THE UPPER MIDWEST WILL BRING A PERIOD OF UNSETTLED
WEATHER WITH OCCASIONAL ROUNDS OF RAIN AND THUNDERSTORMS FROM MONDAY
THROUGH WEDNESDAY. FAIR AND COOLER WEATHER IS EXPECTED LATE IN THE
WEEK.

&&

.UPDATE...
ISSUED AT 1100 AM EDT SAT MAY 18 2013

SATELLITE TRENDS SHOW THE CLOUD COVER DECREASING ACROSS THE REGION
AT THIS TIME. FORECAST SOUNDINGS KEEP THE ATMOSPHERIC RELATIVELY
HUMIDITY LOW THROUGH THE AFTERNOON. CI IN WRN WI FROM THOSE STORMS
COULD ARRIVE IN SOUTHWEST MI LATER IN THE DAY. FOR THE MOST PART
MUCH OF THE REGION WILL SEEN MOSTLY SUNNY SKIES.  AS A RESULT WILL
FEATURE MORE IN THE WAY OF SUNSHINE FOR THE REMAINDER OF THE
AFTERNOON. THE LAKE BREEZE AROUND SOUTH HAVEN COULD TOUCH OFF A
BRIEF RAIN SHOWER AS THERE IS SOME VERY THIN CAPE FOR LIFTED
AFTERNOON PARCELS. THIS POTENTIAL THOUGH IS SMALL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT MAY 18 2013

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE PROBABILITIES
FOR SHOWERS AND STORMS MAINLY FOR MONDAY.

FAIR AND MILD WX IS ANTICIPATED THROUGH THE WEEKEND WITH MAX TEMPS
WELL INTO THE 70S TO NEAR 80 DEGREES TODAY AND A FEW DEGREES WARMER
THAN THAT FOR SUNDAY.

THERE IS JUST SLIGHT CHC OF A SHOWER THIS AFTN SW OF KGRR WHERE SOME
INSTABILITY WILL DEVELOP. AN OVERALL CONSENSUS OF 00Z SHORT RANGE
GUIDANCE SUGGESTS PROBABILITIES FOR A SHOWER THERE WOULD BE REALLY
LOW.

THE WX PATTERN WILL BECOME MORE UNSETTLED AND ACTIVE BEGINNING
MONDAY... PARTICULARLY IN THE AFTERNOON. WE BOOSTED MAX TEMPS UP BY
SEVERAL DEGREES FOR MONDAY WITH THE EXPECTATION OF A FAIR AMOUNT OF
SUN AND SOUTHERLY FLOW WAA BY THEN.

THIS WILL LEAD TO INCREASING INSTABILITY WITH POTENTIAL FOR SB CAPES
TO REACH 2000-3000 J/KG MONDAY AFTERNOON AND AS THE UPPER RIDGE AXIS
SHIFTS EAST AND SOME PVA BEGINS TO MOVE IN FROM THE SW LATE IN THE
DAY. MOISTURE WILL ALSO BE ON THE INCREASE IN THE SOUTHERLY FLOW WAA
REGIME ALLOWING DEW POINT VALUES TO CLIMB INTO THE 60S. SO THE
THREAT FOR SHOWERS AND STORMS WILL BEGIN TO RAMP UP BEGINNING MONDAY
AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT MAY 18 2013

LONG TERM PERIOD LOOKS TO BE A WET TIME FRAME...AS AN UPPER LOW IN
THE NORTHERN PLAINS SLOWLY WORKS INTO AND THROUGH THE REGION DURING
THIS TIME FRAME. IN FACT...YESTERDAY EVENING/S 7 DAY EXPERIMENTAL
PRECIPITATION PRODUCT FROM WPC WAS INDICATING 1 TO AROUND 2 INCHES
OF RAINFALL ACROSS THE SOUTHWEST QUARTER OF LOWER MI.

A WARM FRONTAL BOUNDARY WILL BE NEARBY OR DRAPED ACROSS THE FORECAST
AREA FOR MUCH OF THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
DURING THIS TIME WE HAVE LIKELY CHANCES (60/70 PCT) FOR
SHOWERS/STORMS FOR MOST OF THE FORECAST AREA.

A DEEP SOUTHERLY FLOW WILL BE IN PLACE EMANATING FROM THE GULF
COAST...WHICH IS SOMETHING WE HAVE LACKED THIS MONTH. PRECIPITABLE
WATER VALUES WILL BE ON THE ORDER OF AN INCH TO AN INCH AND A HALF
INTO MID WEEK.

DIFFICULT TO NAIL DOWN ANY SPECIFIC SEVERE THREAT TIME FRAMES...BUT
MONDAY AFTERNOON AND EVENING AND AGAIN ON WEDNESDAY MAY BE TIMES TO
WATCH. HEATING TO AID IN INSTABILITY WILL BE THE DIFFICULT VARIABLE
TO PINPOINT GIVEN THE AMOUNT OF CLOUDS AND PRECIP AROUND. IF WE CAN
HEAT DURING THE DAYLIGHT HOURS THOUGH INSTABILITY SHOULD BUILD
READILY.

LATE IN THE WEEK THE LOW WILL SLIDE EAST FINALLY AND HIGH PRESSURE
WILL BEGIN TO BUILD IN FROM THE NORTH. HAVE A DRY FORECAST TOWARD
WEEKS END.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1241 PM EDT SAT MAY 18 2013

VFR CIGS EXPECTED THROUGH THE PERIOD. HOWEVER AS DEWPOINTS
INCREASE LATE TONIGHT WE MAY SEE SOME FOG DEVELOP WITH VSBYS
FALLING TO 4-5SM BR PRIOR TO SUNRISE.

&&

.MARINE...
ISSUED AT 1100 AM EDT SAT MAY 18 2013

WINDS AND WAVES WILL REMAIN LOW GIVEN THE WEAK PRESSURE GRADIENT
AND GENERAL OFFSHORE COMPONENT TO THE WIND INTO SUNDAY


&&

.FIRE WEATHER...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FIRE WEATHER CONCERNS ARE FAIRLY MINIMAL DUE TO INCREASING DEW POINT
VALUES AND RELATIVE HUMIDITY VALUES THIS WEEKEND AND FAIRLY LOW WIND
SPEEDS MAINLY UNDER 15 MPH. SEVERAL ROUNDS OF RAIN AND STORMS ARE
EXPECTED MONDAY THROUGH WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 330 AM EDT SAT MAY 18 2013

SEVERAL ROUNDS OF SHOWERS AND STORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY WITH TOTAL RAINFALL AMOUNTS ON AVERAGE IN THAT TIME FRAME
OF AROUND AN INCH TO INCH AND A HALF POSSIBLE WITH LOCALLY HIGHER
AMOUNTS WITH HEAVIER STORMS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...93
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...MJS

000
FXUS63 KGRR 181508
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1108 AM EDT SAT MAY 18 2013

LATEST UPDATE...
UPDATE/MARINE

.SYNOPSIS...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FAIR AND MILD WEATHER IS ANTICIPATED THIS WEEKEND. A LOW PRESSURE
SYSTEM OVER THE UPPER MIDWEST WILL BRING A PERIOD OF UNSETTLED
WEATHER WITH OCCASIONAL ROUNDS OF RAIN AND THUNDERSTORMS FROM MONDAY
THROUGH WEDNESDAY. FAIR AND COOLER WEATHER IS EXPECTED LATE IN THE
WEEK.

&&

.UPDATE...
ISSUED AT 1100 AM EDT SAT MAY 18 2013

SATELLITE TRENDS SHOW THE CLOUD COVER DECREASING ACROSS THE REGION
AT THIS TIME. FORECAST SOUNDINGS KEEP THE ATMOSPHERIC RELATIVELY
HUMIDITY LOW THROUGH THE AFTERNOON. CI IN WRN WI FROM THOSE STORMS
COULD ARRIVE IN SOUTHWEST MI LATER IN THE DAY. FOR THE MOST PART
MUCH OF THE REGION WILL SEEN MOSTLY SUNNY SKIES.  AS A RESULT WILL
FEATURE MORE IN THE WAY OF SUNSHINE FOR THE REMAINDER OF THE
AFTERNOON. THE LAKE BREEZE AROUND SOUTH HAVEN COULD TOUCH OFF A
BRIEF RAIN SHOWER AS THERE IS SOME VERY THIN CAPE FOR LIFTED
AFTERNOON PARCELS. THIS POTENTIAL THOUGH IS SMALL.


&&

.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT MAY 18 2013

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE PROBABILITIES
FOR SHOWERS AND STORMS MAINLY FOR MONDAY.

FAIR AND MILD WX IS ANTICIPATED THROUGH THE WEEKEND WITH MAX TEMPS
WELL INTO THE 70S TO NEAR 80 DEGREES TODAY AND A FEW DEGREES WARMER
THAN THAT FOR SUNDAY.

THERE IS JUST SLIGHT CHC OF A SHOWER THIS AFTN SW OF KGRR WHERE SOME
INSTABILITY WILL DEVELOP. AN OVERALL CONSENSUS OF 00Z SHORT RANGE
GUIDANCE SUGGESTS PROBABILITIES FOR A SHOWER THERE WOULD BE REALLY
LOW.

THE WX PATTERN WILL BECOME MORE UNSETTLED AND ACTIVE BEGINNING
MONDAY... PARTICULARLY IN THE AFTERNOON. WE BOOSTED MAX TEMPS UP BY
SEVERAL DEGREES FOR MONDAY WITH THE EXPECTATION OF A FAIR AMOUNT OF
SUN AND SOUTHERLY FLOW WAA BY THEN.

THIS WILL LEAD TO INCREASING INSTABILITY WITH POTENTIAL FOR SB CAPES
TO REACH 2000-3000 J/KG MONDAY AFTERNOON AND AS THE UPPER RIDGE AXIS
SHIFTS EAST AND SOME PVA BEGINS TO MOVE IN FROM THE SW LATE IN THE
DAY. MOISTURE WILL ALSO BE ON THE INCREASE IN THE SOUTHERLY FLOW WAA
REGIME ALLOWING DEW POINT VALUES TO CLIMB INTO THE 60S. SO THE
THREAT FOR SHOWERS AND STORMS WILL BEGIN TO RAMP UP BEGINNING MONDAY
AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT MAY 18 2013

LONG TERM PERIOD LOOKS TO BE A WET TIME FRAME...AS AN UPPER LOW IN
THE NORTHERN PLAINS SLOWLY WORKS INTO AND THROUGH THE REGION DURING
THIS TIME FRAME. IN FACT...YESTERDAY EVENING/S 7 DAY EXPERIMENTAL
PRECIPITATION PRODUCT FROM WPC WAS INDICATING 1 TO AROUND 2 INCHES
OF RAINFALL ACROSS THE SOUTHWEST QUARTER OF LOWER MI.

A WARM FRONTAL BOUNDARY WILL BE NEARBY OR DRAPED ACROSS THE FORECAST
AREA FOR MUCH OF THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
DURING THIS TIME WE HAVE LIKELY CHANCES (60/70 PCT) FOR
SHOWERS/STORMS FOR MOST OF THE FORECAST AREA.

A DEEP SOUTHERLY FLOW WILL BE IN PLACE EMANATING FROM THE GULF
COAST...WHICH IS SOMETHING WE HAVE LACKED THIS MONTH. PRECIPITABLE
WATER VALUES WILL BE ON THE ORDER OF AN INCH TO AN INCH AND A HALF
INTO MID WEEK.

DIFFICULT TO NAIL DOWN ANY SPECIFIC SEVERE THREAT TIME FRAMES...BUT
MONDAY AFTERNOON AND EVENING AND AGAIN ON WEDNESDAY MAY BE TIMES TO
WATCH. HEATING TO AID IN INSTABILITY WILL BE THE DIFFICULT VARIABLE
TO PINPOINT GIVEN THE AMOUNT OF CLOUDS AND PRECIP AROUND. IF WE CAN
HEAT DURING THE DAYLIGHT HOURS THOUGH INSTABILITY SHOULD BUILD
READILY.

LATE IN THE WEEK THE LOW WILL SLIDE EAST FINALLY AND HIGH PRESSURE
WILL BEGIN TO BUILD IN FROM THE NORTH. HAVE A DRY FORECAST TOWARD
WEEKS END.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 749 AM EDT SAT MAY 18 2013

VFR CONDITIONS ARE EXPECTED TO PREVAIL THE NEXT 24 HOURS...OR
THROUGH 12Z SUNDAY. MID CLOUDS DOMINATE THE SKY AT 12Z THIS
MORNING...AND THESE SHOULD GRADUALLY THIN THROUGH THE COURSE OF
THE DAY. BASES OF THESE CLOUDS ARE BETWEEN 8000FT AND 12000FT.

CUMULUS CLOUDS WILL FILL IN THROUGH THE AFTERNOON WITH BASES AROUND
5000-6000FT. THESE CLOUDS WILL LIKELY REMAIN IN THE AREA THROUGH
THE NIGHT.

SMALL CHANCES FOR ISOLATED RAIN SHOWERS EXIST THIS AFTERNOON...
POSSIBLY AFFECTING THE KMKG...KAZO AND KGRR TAF SITES. CHANCES ARE
TOO SMALL TO INCLUDE IN THE TAFS AT THIS POINT. WINDS WILL BE
LIGHT EASTERLY BOTH TODAY AT TONIGHT BETWEEN 5 AND 10 KNOTS.


&&

.MARINE...
ISSUED AT 1100 AM EDT SAT MAY 18 2013

WINDS AND WAVES WILL REMAIN LOW GIVEN THE WEAK PRESSURE GRADIENT
AND GENERAL OFFSHORE COMPONENT TO THE WIND INTO SUNDAY

&&

.FIRE WEATHER...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FIRE WEATHER CONCERNS ARE FAIRLY MINIMAL DUE TO INCREASING DEW POINT
VALUES AND RELATIVE HUMIDITY VALUES THIS WEEKEND AND FAIRLY LOW WIND
SPEEDS MAINLY UNDER 15 MPH. SEVERAL ROUNDS OF RAIN AND STORMS ARE
EXPECTED MONDAY THROUGH WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 330 AM EDT SAT MAY 18 2013

SEVERAL ROUNDS OF SHOWERS AND STORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY WITH TOTAL RAINFALL AMOUNTS ON AVERAGE IN THAT TIME FRAME
OF AROUND AN INCH TO INCH AND A HALF POSSIBLE WITH LOCALLY HIGHER
AMOUNTS WITH HEAVIER STORMS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...DUKE
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...MJS

000
FXUS63 KAPX 181410
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1010 AM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 317 AM EDT SAT MAY 18 2013

HIGH PRESSURE WILL EXIT TO THE EAST...ALLOWING FOR WARMER CONDITIONS
ALONG WITH A CHANCE FOR SHOWERS OVER THE WEEKEND. A STORM SYSTEM
CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO THE PLAINS
TODAY...AND INTO THE GREAT LAKES TO START THE WORK WEEK. THIS WILL
GENERATE SHOWERS AND THUNDERSTORMS OVER NORTHERN MICHIGAN BEGINNING
MONDAY AND CONTINUING THROUGH MIDWEEK.

&&

.UPDATE...
ISSUED AT 948 AM EDT SAT MAY 18 2013

ELEVATED WARM FRONT GRADUALLY SLIDING TO THE NORTH THIS MORNING
WITH DEEPEST FORCING/MOISTURE REMAINING WEST OF OUR AREA. DESPITE
LITTLE MOISTURE BELOW 800MB ACROSS NORTHERN MICHIGAN...STILL
ENOUGH FORCING TO CREATE PATCHY LIGHT RAIN AND SPRINKLES /SPOTTER
REPORTS UP TO 0.06 INCHES OF RAIN/. FORCING WILL DIMINISH OVER THE
NEXT SEVERAL HOURS AS EVERYTHING GRADUALLY PUSHES TO THE NORTH.
EXPECT CURRENT AREA OF LIGHT PCPN TO GRADUALLY DIMINISH THROUGH
EARLY AFTERNOON AS IT PUSHES INTO EASTERN UPPER/TIP OF THE MITT.
LIKELY STILL SOME SPRINKLES OVER PORTIONS OF NORTHERN LOWER INTO
THE AFTERNOON WITH LINGERING FORCING AND PLENTY OF MID CLOUD.
PREVAILING CLOUDY SKIES TODAY...WITH SOME BREAKS LIKELY OVER
SRN/SW AREAS. LOWERED TEMPS IN MANY AREAS THIS AFTERNOON...ESPECIALLY
GAYLORD NORTHWARD WITH MORE CLOUDS AND LIGHT PCPN.

UPDATE ISSUED AT 650 AM EDT SAT MAY 18 2013

ISOLD LIGHT SHOWERS CONTINUE TO IMPACT THE SW HALF OF OUR CWA
EARLY THIS MORNING AS LIMITED LOW/MID LEVEL MOISTURE LIFT INTO NRN
MICHIGAN NORTH OF A WARM FRONT. THUNDERSTORMS CONTINUE TO FIRE
WELL UPSTREAM OVER MINNESOTA IN THE VCNTY OF AN 850 MB THETA E
RIDGE AND INSTABILITY AXIS. LATEST NAM STILL POINTS TOWARD THIS
INSTABILITY AND DEEPER MOISTURE REMAINING UPSTREAM OF OUR CWA THRU
THE DAY...WITH ONLY SOME ISOLATED SHOWERS AND MAINLY CLOUDY SKIES
EXPECTED FOR US TODAY. THESE ISOLD SHOWERS WILL GRADUALLY LIFT
NORTHWARD INTO THE REST OF OUR CWA THRU THE DAY AS THE WARM FRONT
EDGES CLOSER. NO CHANGES ARE NEEDED TO THE TIMING OF WX/POPS FOR
NOW.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 317 AM EDT SAT MAY 18 2013

ON THE LATEST SURFACE WEATHER MAP...1025 MB HIGH PRESSURE WAS
CENTERED OVER SOUTHEAST ONTARIO WITH 1002 MB LOW PRESSURE ALONG THE
FRONT RANGE OF THE CENTRAL ROCKIES. APX AND SURROUNDING RADARS
SHOWED A FEW LIGHT RAIN SHOWERS SPRINKLED ACROSS PORTIONS OF NORTH
CENTRAL LOWER MICHIGAN. THE MAIN SHORT TERM FORECAST CONCERNS CENTER
AROUND POPS AND HIGH TEMPERATURES TODAY.

TODAY INTO TONIGHT...MORE OF THE SAME WITH SUBTLE WARM FRONT AND
INCREASING THETA-E RIDGING (MOISTURE) ADVECTING INTO THE REGION FROM
THE SOUTHWEST. THE MAIN FORCING/BETTER MOISTURE REMAIN TO OUR WEST
CLOSER TO PARENT UPPER LOW SPINNING ITS WHEELS ACROSS THE ROCKIES.
LOOKING AT MODEL CROSS SECTIONS...LOWER LEVELS REMAIN RATHER DRY
WITH ABUNDANT MID LEVEL MOISTURE (FROM ABOUT 850 TO JUST BELOW 500
MB). SO EXPECT MOSTLY CLOUDY SKIES WITH ISOLATED LIGHT RAIN SHOWERS
MARCHING FROM SOUTHWEST TO NORTHEAST THROUGH THE DAY. MAINLY DRY
TONIGHT WITH PERHAPS JUST A FEW LEFTOVER ISOLATED RAIN SHOWERS
ACROSS THE FAR NORTH. TEMPERATURES ARE A BIT TRICKY TODAY WITH
ABUNDANT CLOUD COVER AND WEAK WARM ADVECTION. HIGHS EXPECTED TO
RANGE FROM THE MIDDLE 60S NORTH TO THE MIDDLE 70S SOUTH. LOWS
TONIGHT RANGING FROM THE MIDDLE 40S TO LOWER 50S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM EDT SAT MAY 18 2013

SUNDAY...WILL BE THE BEST WEATHER DAY OF THE WEEKEND. ERN EDGE OF A
WARM FRONT WILL LIFT NORTHWARD INTO UPPER MICHIGAN. SOUTHERLY FLOW
SOUTH OF THE WARM FRONT WILL BOOST TEMPS INTO THE LOW TO MID 70S
ACROSS ERN UPR MICHIGAN AND INTO THE UPPER 70S AND LOWER 80S ACROSS
NRN LWR MICHIGAN. STILL APPEARS SUNDAY WILL BE DRY WITH PARTLY SUNNY
SKIES...AND WILL LIKELY SERVE AS OUR LAST COMPLETELY DRY DAY FOR
MOST OF NEXT WORK WEEK (MORE ON THIS BELOW). AT THIS POINT...SUNDAY
EVENING SHOULD REMAIN DRY...BUT PRECIP CHANCES WILL BEGIN TO
INCREASE ACROSS OUR WRN CWA LATE SUNDAY NIGHT AS AN INITIAL SHORT
WAVE ACCOMPANIED BY BETTER MOISTURE ARRIVE TOWARD DAYBREAK.

MONDAY THRU WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE
FROM WEST TO EAST ON MONDAY AS THE WARM FRONT SAGS SOUTHWARD INTO
NRN LWR MICHIGAN. DEVELOPING LOW PRESSURE IN THE PLAINS WILL BEGIN
TO TAP INTO GULF MOISTURE...ADVECTING IT NORTHWARD THRU THE LOWER
AND MID MISSISSIPPI VALLEY AND INTO THE WRN GREAT LAKES. AS THIS
DEEPER MOISTURE BEGINS TO INTERACT WITH THE WARM FRONT AND A SERIES
OF SHORT WAVES RIDING NE THRU MICHIGAN AHEAD OF THE DEEPENING UPPER
LOWER...WAVES OF SHOWERS AND STORMS WILL REMAIN THE RULE BEGINNING
MONDAY AND CONTINUING THRU WEDNESDAY NIGHT. SURFACE AND CLOSED UPPER
LOW BECOME VERTICALLY STACKED...THUS MAKING VERY SLOW EASTWARD
PROGRESS OVER THIS TIME PERIOD...AND THEREFORE KEEPING OUR WEATHER
UNSETTLED THRU MID WEEK (AT LEAST). WARM TEMPS WILL HOLD OVER THE
REGION ON MONDAY BEFORE THE WARM FRONT SAGS SOUTH ON TUESDAY AND
WEDNESDAY. HIGH TEMPS ON MONDAY WILL RANGE FROM AROUND 70 DEGREES
ACROSS ERN UPR MICHIGAN NORTH OF THE WARM FRONT TO THE MID 70S TO
LOWER 80S SOUTH OF THE WARM FRONT. HIGH TEMPS WILL ONLY REACH INTO
THE 60S BOTH TUESDAY AND WEDNESDAY AS THE WARM FRONT CONTINUES TO
DROP SOUTH OF OUR CWA.

THURSDAY AND FRIDAY...SURFACE AND UPPER LOW CENTERS WILL SLOWLY
SLIDE THRU LWR MICHIGAN ON THURSDAY...EXITING EAST TOWARD NEW
ENGLAND BY FRIDAY. SOME SHOWERS WILL LINGER ACROSS OUR CWA THURSDAY
AROUND AND JUST NORTH OF THE SURFACE LOW CENTER...BUT SHOULD COME TO
AN END BY FRIDAY AS DRIER AIR FILTERS INTO THE REGION BEHIND THE
DEPARTING LOW. THE COLDER AIR BEHIND THIS SYSTEM WILL NOT ARRIVE
UNTIL SATURDAY. NEUTRAL TEMP ADVECTION WILL LEND TO HIGH TEMPS
REMAINING IN THE 60S FOR BOTH THURSDAY AND FRIDAY. A FIRST LOOK AT
NEXT WEEKEND LOOKS DRY BUT POTENTIALLY COOLER THAN NORMAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM EDT SAT MAY 18 2013

BKN/OVC MID CLOUD WILL REMAIN OVER ALL OF NRN LWR MICHIGAN THRU
SUNDAY MORNING THANKS TO MID LEVEL MOISTURE NORTH OF A WARM FRONT
TO OUR SOUTH. SCT/BKN LOW CLOUDS AND A FEW SHOWERS ARE EXPECTED TO
IMPACT PORTIONS OF NRN LWR MICHIGAN THRU THE DAY AS WELL...BUT VFR
CONDITIONS WILL REMAIN THE RULE FOR THE NEXT 24 HOURS. SOUTHEAST
WINDS WILL STRENGTHEN TO AROUND 10 KTS THIS MORNING.


&&

.MARINE...
ISSUED AT 317 AM EDT SAT MAY 18 2013

SOUTH-SOUTHEAST FLOW SLOWLY INCREASES TODAY THROUGH SUNDAY...AND  A
HANDFUL OF SMALL CRAFT ADVISORIES MAY BE NEEDED AT SOME POINT LATER
IN THE WEEKEND.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JK
SYNOPSIS...MR
SHORT TERM...AS
LONG TERM...MR
AVIATION...MR
MARINE...AS

000
FXUS63 KGRR 181150
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
750 AM EDT SAT MAY 18 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FAIR AND MILD WEATHER IS ANTICIPATED THIS WEEKEND. A LOW PRESSURE
SYSTEM OVER THE UPPER MIDWEST WILL BRING A PERIOD OF UNSETTLED
WEATHER WITH OCCASIONAL ROUNDS OF RAIN AND THUNDERSTORMS FROM MONDAY
THROUGH WEDNESDAY. FAIR AND COOLER WEATHER IS EXPECTED LATE IN THE
WEEK.

&&

.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT MAY 18 2013

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE PROBABILITIES
FOR SHOWERS AND STORMS MAINLY FOR MONDAY.

FAIR AND MILD WX IS ANTICIPATED THROUGH THE WEEKEND WITH MAX TEMPS
WELL INTO THE 70S TO NEAR 80 DEGREES TODAY AND A FEW DEGREES WARMER
THAN THAT FOR SUNDAY.

THERE IS JUST SLIGHT CHC OF A SHOWER THIS AFTN SW OF KGRR WHERE SOME
INSTABILITY WILL DEVELOP. AN OVERALL CONSENSUS OF 00Z SHORT RANGE
GUIDANCE SUGGESTS PROBABILITIES FOR A SHOWER THERE WOULD BE REALLY
LOW.

THE WX PATTERN WILL BECOME MORE UNSETTLED AND ACTIVE BEGINNING
MONDAY... PARTICULARLY IN THE AFTERNOON. WE BOOSTED MAX TEMPS UP BY
SEVERAL DEGREES FOR MONDAY WITH THE EXPECTATION OF A FAIR AMOUNT OF
SUN AND SOUTHERLY FLOW WAA BY THEN.

THIS WILL LEAD TO INCREASING INSTABILITY WITH POTENTIAL FOR SB CAPES
TO REACH 2000-3000 J/KG MONDAY AFTERNOON AND AS THE UPPER RIDGE AXIS
SHIFTS EAST AND SOME PVA BEGINS TO MOVE IN FROM THE SW LATE IN THE
DAY. MOISTURE WILL ALSO BE ON THE INCREASE IN THE SOUTHERLY FLOW WAA
REGIME ALLOWING DEW POINT VALUES TO CLIMB INTO THE 60S. SO THE
THREAT FOR SHOWERS AND STORMS WILL BEGIN TO RAMP UP BEGINNING MONDAY
AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT MAY 18 2013

LONG TERM PERIOD LOOKS TO BE A WET TIME FRAME...AS AN UPPER LOW IN
THE NORTHERN PLAINS SLOWLY WORKS INTO AND THROUGH THE REGION DURING
THIS TIME FRAME. IN FACT...YESTERDAY EVENING/S 7 DAY EXPERIMENTAL
PRECIPITATION PRODUCT FROM WPC WAS INDICATING 1 TO AROUND 2 INCHES
OF RAINFALL ACROSS THE SOUTHWEST QUARTER OF LOWER MI.

A WARM FRONTAL BOUNDARY WILL BE NEARBY OR DRAPED ACROSS THE FORECAST
AREA FOR MUCH OF THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
DURING THIS TIME WE HAVE LIKELY CHANCES (60/70 PCT) FOR
SHOWERS/STORMS FOR MOST OF THE FORECAST AREA.

A DEEP SOUTHERLY FLOW WILL BE IN PLACE EMANATING FROM THE GULF
COAST...WHICH IS SOMETHING WE HAVE LACKED THIS MONTH. PRECIPITABLE
WATER VALUES WILL BE ON THE ORDER OF AN INCH TO AN INCH AND A HALF
INTO MID WEEK.

DIFFICULT TO NAIL DOWN ANY SPECIFIC SEVERE THREAT TIME FRAMES...BUT
MONDAY AFTERNOON AND EVENING AND AGAIN ON WEDNESDAY MAY BE TIMES TO
WATCH. HEATING TO AID IN INSTABILITY WILL BE THE DIFFICULT VARIABLE
TO PINPOINT GIVEN THE AMOUNT OF CLOUDS AND PRECIP AROUND. IF WE CAN
HEAT DURING THE DAYLIGHT HOURS THOUGH INSTABILITY SHOULD BUILD
READILY.

LATE IN THE WEEK THE LOW WILL SLIDE EAST FINALLY AND HIGH PRESSURE
WILL BEGIN TO BUILD IN FROM THE NORTH. HAVE A DRY FORECAST TOWARD
WEEKS END.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 749 AM EDT SAT MAY 18 2013

VFR CONDITIONS ARE EXPECTED TO PREVAIL THE NEXT 24 HOURS...OR
THROUGH 12Z SUNDAY. MID CLOUDS DOMINATE THE SKY AT 12Z THIS
MORNING...AND THESE SHOULD GRADUALLY THIN THROUGH THE COURSE OF
THE DAY. BASES OF THESE CLOUDS ARE BETWEEN 8000FT AND 12000FT.

CUMULUS CLOUDS WILL FILL IN THROUGH THE AFTERNOON WITH BASES AROUND
5000-6000FT. THESE CLOUDS WILL LIKELY REMAIN IN THE AREA THROUGH
THE NIGHT.

SMALL CHANCES FOR ISOLATED RAIN SHOWERS EXIST THIS AFTERNOON...
POSSIBLY AFFECTING THE KMKG...KAZO AND KGRR TAF SITES. CHANCES ARE
TOO SMALL TO INCLUDE IN THE TAFS AT THIS POINT. WINDS WILL BE
LIGHT EASTERLY BOTH TODAY AT TONIGHT BETWEEN 5 AND 10 KNOTS.

&&

.MARINE...
ISSUED AT 330 AM EDT SAT MAY 18 2013

OFFSHORE EASTERLY WINDS WILL RESULT IN MINIMAL WAVE HEIGHTS THIS
WEEKEND. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS MONDAY THROUGH
WEDNESDAY.


&&

.FIRE WEATHER...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FIRE WEATHER CONCERNS ARE FAIRLY MINIMAL DUE TO INCREASING DEW POINT
VALUES AND RELATIVE HUMIDITY VALUES THIS WEEKEND AND FAIRLY LOW WIND
SPEEDS MAINLY UNDER 15 MPH. SEVERAL ROUNDS OF RAIN AND STORMS ARE
EXPECTED MONDAY THROUGH WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 330 AM EDT SAT MAY 18 2013

SEVERAL ROUNDS OF SHOWERS AND STORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY WITH TOTAL RAINFALL AMOUNTS ON AVERAGE IN THAT TIME FRAME
OF AROUND AN INCH TO INCH AND A HALF POSSIBLE WITH LOCALLY HIGHER
AMOUNTS WITH HEAVIER STORMS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...DUKE
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS
MARINE...LAURENS

000
FXUS63 KMQT 181149
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
749 AM EDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SAT MAY 18 2013

IN THE LARGE SCALE...TROUGH OVER THE ROCKIES WILL SLIDE ONTO THE
HIGH PLAINS BY SUNDAY MORNING ALLOWING RIDGING TO SLIGHTLY BUILD
OVER THE WESTERN GREAT LAKES. ALTHOUGH SFC-H85 TROUGHING OVER THE
DAKOTAS DOES NOT MOVE MUCH TO THE EAST...IT IS ENOUGH TO INCREASE
LOW-LEVEL SOUTHERLY FLOW ACROSS THE UPPER GREAT LAKES. PATTERN IS
SERVING TO INCREASE MOISTURE /PWATS 1.15 OF 1.31 INCHES AT GRB AND
MPX OR AROUND 200 PCT OF NORMAL/ IN WAKE OF DRY SFC HIGH THAT HAS
BEEN ESTABLISHED OVER THE AREA FOR MOST OF THIS WEEK. REGIONAL RADAR
SHOWS DECAYING ECHOES OVER NORTHERN WISCONSIN. MUCH MORE ORGANIZED
AREA OF SHRA/TSRA HAVE DEVELOPED SINCE 03Z FROM CENTRAL MINNESOTA
INTO WEST CENTRAL WISCONSIN ALONG H85 WARM FRONT/GRADIENT OF H85
THETA-E. ADDITIONAL AREA OF SHRA/TSRA SPREADING ACROSS NORTHEAST
SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA NEAR CONVECTIVE INDUCED
SHORTAVE/H7-H3 DIFFERENTIAL PVA AND CLOSE TO H7 MOISTURE TRANSPORT.
JUST RECENTLY ANOTHER LARGE CLUSTER OF SHRA/TSRA HAVE FORMED IN THE
WARM AIR ADVECTION REGIME BTWN THESE TWO INITIAL AREAS OF PRECIP.

GIVEN EXTENT OF SHRA/TSRA UPSTREAM OF CWA THIS MORNING AND SINCE
H85-H7 MOISTURE ADVECTION IS FORECAST WEST TO EAST ACROSS CWA
THROUGH THE DAY...INCREASED POPS FOR MOST OF THE WEST AND NORTHERN
CWA AS AT LEAST MULTIPLE REMNANTS OF THIS CONVECTION SHOULD MAKE IT
INTO UPR MICHIGAN. LEANED ON THE NCEP WRF MODELS AND RECENT HRRR AND
EXTRAPOLATION OF LATEST HRRR TO CREATE POPS. RESULT IS LIKELY POPS
MOST OF THE DAY OVER THE WEST HALF...WITH SMALLER CHANCES FARTHER
EAST AS THE RAIN RUNS INTO THE VERY DRY AIRMASS ASSOCIATED WITH SFC
HIGH TO THE EAST. MAJORITY OF TSRA THUS FAR STAYING OVER NORTHERN
MINNESOTA ON GRADIENT OF 1-6KM MUCAPE RESERVOIR. HINT IN MODELS
THAT EASTERN EDGE OF INSTABILITY GRADIENT SLIDES TOWARD WESTERN UPR
MICHIGAN SO HAVE INCLUDED SLIGHT CHANCES FOR TSRA. CONVECTION IS
ELEVATED AND MID-LEVEL LAPSE RATES BARELY GET ABOVE 6C/KM. MAIN
ISSUE WILL BE HEAVY DOWNPOURS AND LIGHTNING STRIKES. TEMPS TODAY
A BIT TOUGH TO FIGURE OUT. EAST GRADIENT WINDS SHOULD KEEP KEWEENAW
CHILLY WITH READINGS STAYING BLO 50 DEGREES. MIXING TO H9 IS PROBABLY
IT WHERE CLOUDS/RAIN PERSIST MOST OF THE DAY. THIS SUPPORTS MAJORITY
OF CWA SEEING HIGHS IN THE 60S...EVENTUALLY...ONCE THE STEADIER RAIN
TAPERS OFF THIS AFTN. SFC WARM FRONT MAY TRY TO POKE INTO FAR SW CWA
LATE IN THE DAY. IF THIS OCCURS AND PRECIP TAPERS OFF/ENDS...THEN
THERE IS POTENTIAL FOR HIGHS TO PUSH WELL INTO THE 70S FROM IWD TO
IMT.

H85 FRONT LIFTS NORTH OF MOST CWA THIS EVENING. KEWEENAW STILL CLOSE
ENOUGH TO FRONT AND WITHIN THE RIBBON OF PERSISTENT MOISTURE
ADVECTION SO KEPT SHRA/ISOLD TSRA THERE THROUGH THE EVENING. DRYING
TREND TAKES HOLD OVERNIGHT AS THE FOCUS FOR SHRA/TSRA...H85 WARM
FRONT AND THETA-E GRADIENT...LIFTS WELL TO NORTH OF UPR MICHIGAN.
KEPT SMALL POPS IN AT ISLE ROYALE LATE TONIGHT THOUGH. TEMPS MOSTLY
IN THE 40S EAST WITH FLOW OFF LK MICHIGAN. LESS MODIFIED AIR FARTHER
WEST ALLOWS MINS TO ONLY FALL INTO THE LOW-MID 50S ALONG LK SUPERIOR
AROUND IWD TO ONTONAGON AND EAST TO BARAGA/L`ANSE AND MARQUETTE
AREAS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 510 AM EDT SAT MAY 18 2013

NAM SHOWS THE 500 MB RIDGE OVER THE EASTERN U.S. 12Z SUN WITH
TROUGHING IN THE ROCKIES. THE TROUGH MOVES EAST ON SUNDAY AND PUSHES
THE RIDGE INTO THE LOWER GREAT LAKES 12Z MON WHERE THE MOVEMENT
EASTWARD STOPS THROUGH 12Z TUE. NAM HAS SOME DEEPER MOISTURE AND
850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA 12Z SUN ONWARD. GFS
SHOWS ABOUT THE SAME THING AS WELL.

THIS PERIOD LOOKS PRETTY WET STARTING WITH SUN AFTERNOON THROUGH MON
NIGHT. WITH SLOW MOVEMENT OF SYSTEM INTO AND THROUGH THE AREA AND
ALSO A WARM FRONT NEAR AND TO THE SOUTH OF THE AREA...THIS SETS UP
THE CWA FOR A WIDESPREAD AND LONG LIVED RAIN EVENT WITH SOME HEAVY
RAIN POSSIBLE. AM FORECASTING ANYWHERE FROM .67 INCH OF QPF OVER THE
SOUTH...TO 1.15 INCHES OVER THE EAST TO OVER 2 INCHES OF RAIN IN THE
FAR WEST NEAR IRONWOOD FROM SUNDAY AFTERNOON THROUGH MONDAY NIGHT
AND THIS DOES NOT SEEM UNREASONABLE WITH PLENTY OF MOISTURE TO THE
SOUTH OF THE AREA AND SLOW SYSTEM MOVEMENT. FOR THIS REASON...BUMPED
POPS UP A BIT TO LIKELY TO CATEGORICAL FOR MOST OF THE CWA THROUGH
THEN. SHOULD SEE SOME SUNSHINE ON SUNDAY. MADE A FEW ADJUSTMENTS TO
TEMPERATURES BASED ON LAKE BREEZES AND WIND DIRECTIONS AND LOWERED
THEM A BIT NEAR THE GREAT LAKES SHORELINES. OTHER THAN THAT...NO
REAL BIG CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW AND TROUGH
IN THE NORTHERN AND CENTRAL PLAINS 12Z TUE WHICH MOVE LITTLE INTO
12Z WED. BY 12Z THU...THE TROUGH AND LOW GET PUSHED A BIT FURTHER
EAST TO THE UPPER GREAT LAKES REGION. THE TROUGH AND LOW MOVE
THROUGH BY 12Z FRI WITH RIDGING BUILDING INTO THE PLAINS LATE ON
FRI. SYSTEM WILL BE SLOW TO MOVE THROUGH THE AREA...SO A COUPLE OF
DAYS OF WIDESPREAD RAIN ARE NOT OUT OF THE QUESTION ALONG WITH
COOLER TEMPERATURES WITH GRADUAL SOUTHWARD MOVEMENT OF THE SYSTEM
AWAY FROM THE AREA. THU INTO FRI...THINGS START TO DRY OUT WITH A
COLD FRONT WELL SOUTH OF THE AREA. TEMPERATURES SLIP TO SLIGHTLY
BELOW NORMAL THIS PERIOD. POPS WILL BE HIGHEST IN THE SOUTH CLOSER
TO A WARM FRONT.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 747 AM EDT SAT MAY 18 2013

A WARM FNT MOVING IN FM THE SOUTH WILL BRING SOME -SHRA/MVFR
CIGS...MAINLY AT IWD/CMX WHERE LLVL WARM/MOIST ADVCTN WL BE MOST
PRONOUNCED. MOIST UPSLOPE FLOW OFF LK SUPERIOR MAY RESULT IN IFR
CONDITIONS AT CMX THIS AFTN AND EVENING. FOLLOWING THE WARM FROPA
TONIGHT...EXPECT WSHFT TO THE S WITH RETURN TO PREDOMINANT VFR WX.
THE ONLY EXCEPTION WL BE AT CMX...WHERE PERSISTENT UPSLOPE ESE WIND
AND MOISTER LLVL AIR WL RESULT IN LINGERING MVFR CONDITIONS THROUGH
MUCH OF THE NIGHT. &&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...JLA
MARINE...07

000
FXUS63 KDTX 181109
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
709 AM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

VFR CONDITIONS WILL PERSIST AS WE WILL REMAIN ON THE WESTERN
PERIPHERY OF LARGE HIGH PRESSURE SYSTEM OVER EASTERN CANADA TODAY.
WINDS WILL BE EASTERLY THROUGH THE DAY BEFORE VEERING TO THE
SOUTHEAST BY SUNDAY MORNING. THE EASTERLY FLOW WILL CONTINUE TO PUMP
DRY AIR INTO THE LOW LEVEL KEEPING CIGS GENERALLY AOA 7KFT THIS
AFTERNOON. AN INCREASE IN LOW LEVEL MOISTURE WILL OCCUR BEHIND A
PASSING WARM FRONT SATURDAY NIGHT WHICH WILL ALLOW VSBYS AND CIGS TO
DROP TO MVFR BY EARLY SUNDAY MORNING. THIS WILL QUICKLY MIX OUT
AFTER SUNRISE.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE CEILINGS WILL DROP BELOW 5KFT EARLY SUNDAY
MORNING.

&&

.PREV DISCUSSION...ISSUED 339 AM EDT SAT MAY 18 2013

SHORT TERM...TODAY AND TONIGHT

MID/UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO THE REGION TODAY
WHILE WE REMAIN ON THE WESTERN EXTENT OF A DOME OF HIGH PRESSURE AT
THE SFC CENTERED OVER EASTERN CANADA. EASTERLY WINDS WILL PERSIST
THROUGH TONIGHT DUE TO THE SFC HIGH. THE CONTINUED FEED OF DRY
CONTINENTAL AIR WILL KEEP DEWPOINTS IN THE 40S ONCE AGAIN. MODEL
SOUNDINGS IN FAIRLY GOOD AGREEMENT WITH THE 00Z DTX SOUNDING WITH
THE DEPTH OF DRY AIR IN THE BOUNDARY LAYER CURRENTLY AROUND 9KFT.
THE 700MB WARM FRONT LIFTED THROUGH FRIDAY AFTERNOON AND MODELS SHOW
THE WEAKER 925 MB FRONT WILL FOLLOW NORTHWARD THROUGH TODAY. HARD TO
FIND ANY ADDITIONAL SUPPORT TO HELP THIS KICK OFF ANY SHOWERS THIS
AFTERNOON. MODELS KEEP MOST OF THE SHOWERS OVER THE OHIO VALLEY
WHERE SFC MOISTURE IS MUCH HIGHER. THE LIKELY RESULT WILL END UP
BEING A LOWERING OF THE CLOUD DECK TO AROUND 6-7KFT. WEAK WAA WILL
ALLOW TEMPS TO REBOUND A FEW MORE DEGREES TODAY INTO THE MID/UPPER
70S WITH COOLER TEMPS FOR AREAS IN THE LAKE SHADOW.

LONG TERM...SUNDAY THROUGH FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
ON SUNDAY. ALTHOUGH A SURFACE WARM FRONT WILL LIFT NORTH THROUGH THE
CWA EARLY ON SUNDAY...DRY CONDITIONS ARE EXPECTED TO CONTINUE
DESPITE MUCAPE VALUES APPROACHING 1000 J/KG DURING THE AFTERNOON
HOURS GIVEN THE VERY DRY AND IN PLACE AND STABILIZING EFFECT OF
DOWNWARD MOTION FROM THE UPPER LEVEL RIDGE. THE PASSAGE OF THE WARM
FRONT WILL BRING WARMER AIR TO THE REGION...WITH DAYTIME HIGHS
AROUND THE 80 DEGREE MARK AWAY FROM LAKE HURON.

WARM AIR WILL CONTINUE TO STREAM IN BEHIND THE WARM FRONT EARLY IN
THE WORK WEEK AS SOUTHERLY WINDS BRING A MARKED INCREASE IN MOISTURE
ACROSS SOUTHERN MICHIGAN. THE INCREASED MOISTURE AS WELL AS THE
SHIFT EAST IN THE UPPER LEVEL RIDGE WILL BRING AN INCREASE IN RAIN
CHANCES TO SOUTHEAST MICHIGAN AS THE WEEK PROGRESSES. ALTHOUGH AN
UPPER LEVEL LOW WILL SIT OFF TO THE WEST DURING THE EARLY PART OF
THE WEEK...SEVERAL EMBEDDED SHORTWAVES WILL TAKE ADVANTAGE OF THE
INCREASED INSTABILITY OF 1000 TO 2000 J/KG MONDAY AND TUESDAY. THE
UPPER LEVEL DYNAMICS AND INSTABILITY WILL BRING THE POSSIBILITY FOR
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS TO THE AREA. DESPITE THE
DECENT CAPE VALUES...SHEAR WILL BE VERY WEAK IN THE LOW LEVELS WITH
A RATHER UNIMPRESSIVE HODOGRAPH AND MEAGER HELICITY VALUES. MONDAY
LOOKS TO BE THE WARMEST DAY OF THE UPCOMING WEEK WITH HIGH
TEMPERATURES GETTING INTO THE LOWER TO MIDDLE 80S ACROSS MUCH OF THE
CWA.

ALTHOUGH MODEL DIFFERENCES STILL EXIST...THERE APPEARS TO BE MORE
AGREEMENT IN HANDLING THE CUT OFF LOW OUT TO THE WEST AS IT
PROGRESSES EAST DURING THE MIDDLE OF THE WEEK. THE GFS AND ECMWF
SOLUTIONS MERGE THIS LOW WITH THE NORTHERN STREAM LOW OVER HUDSON
BAY...ABSORBING THE LOW AS A POSITIVELY TILTED TROUGH TRACKING
THROUGH THE CENTRAL GREAT LAKES REGION. ALTHOUGH THUNDERSTORMS ARE
STILL POSSIBLE DURING THE MIDDLE OF THE WEEK...THE BEST INSTABILITY
WILL BE WELL TO THE SOUTH. HOWEVER THE SYSTEM WILL HAVE ENOUGH
MOISTURE TO PRODUCE SOME HEAVY RAIN SHOWERS DURING THE MIDDLE OF THE
WEEK AS THE SURFACE LOW TRACKS THROUGH THE SOUTHERN GREAT LAKES
REGION.

CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE LOW LATE IN THE
WEEK...BRINGING DRY CONDITIONS AND MUCH COOLER DAYTIME HIGHS IN THE
60S TO SOUTHEAST MICHIGAN.

MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....DRK
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 181051
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
651 AM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 317 AM EDT SAT MAY 18 2013

HIGH PRESSURE WILL EXIT TO THE EAST...ALLOWING FOR WARMER CONDITIONS
ALONG WITH A CHANCE FOR SHOWERS OVER THE WEEKEND. A STORM SYSTEM
CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO THE PLAINS
TODAY...AND INTO THE GREAT LAKES TO START THE WORK WEEK. THIS WILL
GENERATE SHOWERS AND THUNDERSTORMS OVER NORTHERN MICHIGAN BEGINNING
MONDAY AND CONTINUING THROUGH MIDWEEK.

&&

.UPDATE...
ISSUED AT 650 AM EDT SAT MAY 18 2013

ISOLD LIGHT SHOWERS CONTINUE TO IMPACT THE SW HALF OF OUR CWA
EARLY THIS MORNING AS LIMITED LOW/MID LEVEL MOISTURE LIFT INTO NRN
MICHIGAN NORTH OF A WARM FRONT. THUNDERSTORMS CONTINUE TO FIRE
WELL UPSTREAM OVER MINNESOTA IN THE VCNTY OF AN 850 MB THETA E
RIDGE AND INSTABILITY AXIS. LATEST NAM STILL POINTS TOWARD THIS
INSTABILITY AND DEEPER MOISTURE REMAINING UPSTREAM OF OUR CWA THRU
THE DAY...WITH ONLY SOME ISOLATED SHOWERS AND MAINLY CLOUDY SKIES
EXPECTED FOR US TODAY. THESE ISOLD SHOWERS WILL GRADUALLY LIFT
NORTHWARD INTO THE REST OF OUR CWA THRU THE DAY AS THE WARM FRONT
EDGES CLOSER. NO CHANGES ARE NEEDED TO THE TIMING OF WX/POPS FOR
NOW.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 317 AM EDT SAT MAY 18 2013

ON THE LATEST SURFACE WEATHER MAP...1025 MB HIGH PRESSURE WAS
CENTERED OVER SOUTHEAST ONTARIO WITH 1002 MB LOW PRESSURE ALONG THE
FRONT RANGE OF THE CENTRAL ROCKIES. APX AND SURROUNDING RADARS
SHOWED A FEW LIGHT RAIN SHOWERS SPRINKLED ACROSS PORTIONS OF NORTH
CENTRAL LOWER MICHIGAN. THE MAIN SHORT TERM FORECAST CONCERNS CENTER
AROUND POPS AND HIGH TEMPERATURES TODAY.

TODAY INTO TONIGHT...MORE OF THE SAME WITH SUBTLE WARM FRONT AND
INCREASING THETA-E RIDGING (MOISTURE) ADVECTING INTO THE REGION FROM
THE SOUTHWEST. THE MAIN FORCING/BETTER MOISTURE REMAIN TO OUR WEST
CLOSER TO PARENT UPPER LOW SPINNING ITS WHEELS ACROSS THE ROCKIES.
LOOKING AT MODEL CROSS SECTIONS...LOWER LEVELS REMAIN RATHER DRY
WITH ABUNDANT MID LEVEL MOISTURE (FROM ABOUT 850 TO JUST BELOW 500
MB). SO EXPECT MOSTLY CLOUDY SKIES WITH ISOLATED LIGHT RAIN SHOWERS
MARCHING FROM SOUTHWEST TO NORTHEAST THROUGH THE DAY. MAINLY DRY
TONIGHT WITH PERHAPS JUST A FEW LEFTOVER ISOLATED RAIN SHOWERS
ACROSS THE FAR NORTH. TEMPERATURES ARE A BIT TRICKY TODAY WITH
ABUNDANT CLOUD COVER AND WEAK WARM ADVECTION. HIGHS EXPECTED TO
RANGE FROM THE MIDDLE 60S NORTH TO THE MIDDLE 70S SOUTH. LOWS
TONIGHT RANGING FROM THE MIDDLE 40S TO LOWER 50S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM EDT SAT MAY 18 2013

SUNDAY...WILL BE THE BEST WEATHER DAY OF THE WEEKEND. ERN EDGE OF A
WARM FRONT WILL LIFT NORTHWARD INTO UPPER MICHIGAN. SOUTHERLY FLOW
SOUTH OF THE WARM FRONT WILL BOOST TEMPS INTO THE LOW TO MID 70S
ACROSS ERN UPR MICHIGAN AND INTO THE UPPER 70S AND LOWER 80S ACROSS
NRN LWR MICHIGAN. STILL APPEARS SUNDAY WILL BE DRY WITH PARTLY SUNNY
SKIES...AND WILL LIKELY SERVE AS OUR LAST COMPLETELY DRY DAY FOR
MOST OF NEXT WORK WEEK (MORE ON THIS BELOW). AT THIS POINT...SUNDAY
EVENING SHOULD REMAIN DRY...BUT PRECIP CHANCES WILL BEGIN TO
INCREASE ACROSS OUR WRN CWA LATE SUNDAY NIGHT AS AN INITIAL SHORT
WAVE ACCOMPANIED BY BETTER MOISTURE ARRIVE TOWARD DAYBREAK.

MONDAY THRU WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE
FROM WEST TO EAST ON MONDAY AS THE WARM FRONT SAGS SOUTHWARD INTO
NRN LWR MICHIGAN. DEVELOPING LOW PRESSURE IN THE PLAINS WILL BEGIN
TO TAP INTO GULF MOISTURE...ADVECTING IT NORTHWARD THRU THE LOWER
AND MID MISSISSIPPI VALLEY AND INTO THE WRN GREAT LAKES. AS THIS
DEEPER MOISTURE BEGINS TO INTERACT WITH THE WARM FRONT AND A SERIES
OF SHORT WAVES RIDING NE THRU MICHIGAN AHEAD OF THE DEEPENING UPPER
LOWER...WAVES OF SHOWERS AND STORMS WILL REMAIN THE RULE BEGINNING
MONDAY AND CONTINUING THRU WEDNESDAY NIGHT. SURFACE AND CLOSED UPPER
LOW BECOME VERTICALLY STACKED...THUS MAKING VERY SLOW EASTWARD
PROGRESS OVER THIS TIME PERIOD...AND THEREFORE KEEPING OUR WEATHER
UNSETTLED THRU MID WEEK (AT LEAST). WARM TEMPS WILL HOLD OVER THE
REGION ON MONDAY BEFORE THE WARM FRONT SAGS SOUTH ON TUESDAY AND
WEDNESDAY. HIGH TEMPS ON MONDAY WILL RANGE FROM AROUND 70 DEGREES
ACROSS ERN UPR MICHIGAN NORTH OF THE WARM FRONT TO THE MID 70S TO
LOWER 80S SOUTH OF THE WARM FRONT. HIGH TEMPS WILL ONLY REACH INTO
THE 60S BOTH TUESDAY AND WEDNESDAY AS THE WARM FRONT CONTINUES TO
DROP SOUTH OF OUR CWA.

THURSDAY AND FRIDAY...SURFACE AND UPPER LOW CENTERS WILL SLOWLY
SLIDE THRU LWR MICHIGAN ON THURSDAY...EXITING EAST TOWARD NEW
ENGLAND BY FRIDAY. SOME SHOWERS WILL LINGER ACROSS OUR CWA THURSDAY
AROUND AND JUST NORTH OF THE SURFACE LOW CENTER...BUT SHOULD COME TO
AN END BY FRIDAY AS DRIER AIR FILTERS INTO THE REGION BEHIND THE
DEPARTING LOW. THE COLDER AIR BEHIND THIS SYSTEM WILL NOT ARRIVE
UNTIL SATURDAY. NEUTRAL TEMP ADVECTION WILL LEND TO HIGH TEMPS
REMAINING IN THE 60S FOR BOTH THURSDAY AND FRIDAY. A FIRST LOOK AT
NEXT WEEKEND LOOKS DRY BUT POTENTIALLY COOLER THAN NORMAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM EDT SAT MAY 18 2013

BKN/OVC MID CLOUD WILL REMAIN OVER ALL OF NRN LWR MICHIGAN THRU
SUNDAY MORNING THANKS TO MID LEVEL MOISTURE NORTH OF A WARM FRONT
TO OUR SOUTH. SCT/BKN LOW CLOUDS AND A FEW SHOWERS ARE EXPECTED TO
IMPACT PORTIONS OF NRN LWR MICHIGAN THRU THE DAY AS WELL...BUT VFR
CONDITIONS WILL REMAIN THE RULE FOR THE NEXT 24 HOURS. SOUTHEAST
WINDS WILL STRENGTHEN TO AROUND 10 KTS THIS MORNING.

&&

.MARINE...
ISSUED AT 317 AM EDT SAT MAY 18 2013

SOUTH-SOUTHEAST FLOW SLOWLY INCREASES TODAY THROUGH SUNDAY...AND  A
HANDFUL OF SMALL CRAFT ADVISORIES MAY BE NEEDED AT SOME POINT LATER
IN THE WEEKEND.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...MR
SYNOPSIS...MR
SHORT TERM...AS
LONG TERM...MR
AVIATION...MR
MARINE...AS

000
FXUS63 KMQT 180911
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
511 AM EDT SAT MAY 18 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 510 AM EDT SAT MAY 18 2013

IN THE LARGE SCALE...TROUGH OVER THE ROCKIES WILL SLIDE ONTO THE
HIGH PLAINS BY SUNDAY MORNING ALLOWING RIDGING TO SLIGHTLY BUILD
OVER THE WESTERN GREAT LAKES. ALTHOUGH SFC-H85 TROUGHING OVER THE
DAKOTAS DOES NOT MOVE MUCH TO THE EAST...IT IS ENOUGH TO INCREASE
LOW-LEVEL SOUTHERLY FLOW ACROSS THE UPPER GREAT LAKES. PATTERN IS
SERVING TO INCREASE MOISTURE /PWATS 1.15 OF 1.31 INCHES AT GRB AND
MPX OR AROUND 200 PCT OF NORMAL/ IN WAKE OF DRY SFC HIGH THAT HAS
BEEN ESTABLISHED OVER THE AREA FOR MOST OF THIS WEEK. REGIONAL RADAR
SHOWS DECAYING ECHOES OVER NORTHERN WISCONSIN. MUCH MORE ORGANIZED
AREA OF SHRA/TSRA HAVE DEVELOPED SINCE 03Z FROM CENTRAL MINNESOTA
INTO WEST CENTRAL WISCONSIN ALONG H85 WARM FRONT/GRADIENT OF H85
THETA-E. ADDITIONAL AREA OF SHRA/TSRA SPREADING ACROSS NORTHEAST
SOUTH DAKOTA INTO SOUTHEAST NORTH DAKOTA NEAR CONVECTIVE INDUCED
SHORTAVE/H7-H3 DIFFERENTIAL PVA AND CLOSE TO H7 MOISTURE TRANSPORT.
JUST RECENTLY ANOTHER LARGE CLUSTER OF SHRA/TSRA HAVE FORMED IN THE
WARM AIR ADVECTION REGIME BTWN THESE TWO INITIAL AREAS OF PRECIP.

GIVEN EXTENT OF SHRA/TSRA UPSTREAM OF CWA THIS MORNING AND SINCE
H85-H7 MOISTURE ADVECTION IS FORECAST WEST TO EAST ACROSS CWA
THROUGH THE DAY...INCREASED POPS FOR MOST OF THE WEST AND NORTHERN
CWA AS AT LEAST MULTIPLE REMNANTS OF THIS CONVECTION SHOULD MAKE IT
INTO UPR MICHIGAN. LEANED ON THE NCEP WRF MODELS AND RECENT HRRR AND
EXTRAPOLATION OF LATEST HRRR TO CREATE POPS. RESULT IS LIKELY POPS
MOST OF THE DAY OVER THE WEST HALF...WITH SMALLER CHANCES FARTHER
EAST AS THE RAIN RUNS INTO THE VERY DRY AIRMASS ASSOCIATED WITH SFC
HIGH TO THE EAST. MAJORITY OF TSRA THUS FAR STAYING OVER NORTHERN
MINNESOTA ON GRADIENT OF 1-6KM MUCAPE RESERVOIR. HINT IN MODELS
THAT EASTERN EDGE OF INSTABILITY GRADIENT SLIDES TOWARD WESTERN UPR
MICHIGAN SO HAVE INCLUDED SLIGHT CHANCES FOR TSRA. CONVECTION IS
ELEVATED AND MID-LEVEL LAPSE RATES BARELY GET ABOVE 6C/KM. MAIN
ISSUE WILL BE HEAVY DOWNPOURS AND LIGHTNING STRIKES. TEMPS TODAY
A BIT TOUGH TO FIGURE OUT. EAST GRADIENT WINDS SHOULD KEEP KEWEENAW
CHILLY WITH READINGS STAYING BLO 50 DEGREES. MIXING TO H9 IS PROBABLY
IT WHERE CLOUDS/RAIN PERSIST MOST OF THE DAY. THIS SUPPORTS MAJORITY
OF CWA SEEING HIGHS IN THE 60S...EVENTUALLY...ONCE THE STEADIER RAIN
TAPERS OFF THIS AFTN. SFC WARM FRONT MAY TRY TO POKE INTO FAR SW CWA
LATE IN THE DAY. IF THIS OCCURS AND PRECIP TAPERS OFF/ENDS...THEN
THERE IS POTENTIAL FOR HIGHS TO PUSH WELL INTO THE 70S FROM IWD TO
IMT.

H85 FRONT LIFTS NORTH OF MOST CWA THIS EVENING. KEWEENAW STILL CLOSE
ENOUGH TO FRONT AND WITHIN THE RIBBON OF PERSISTENT MOISTURE
ADVECTION SO KEPT SHRA/ISOLD TSRA THERE THROUGH THE EVENING. DRYING
TREND TAKES HOLD OVERNIGHT AS THE FOCUS FOR SHRA/TSRA...H85 WARM
FRONT AND THETA-E GRADIENT...LIFTS WELL TO NORTH OF UPR MICHIGAN.
KEPT SMALL POPS IN AT ISLE ROYALE LATE TONIGHT THOUGH. TEMPS MOSTLY
IN THE 40S EAST WITH FLOW OFF LK MICHIGAN. LESS MODIFIED AIR FARTHER
WEST ALLOWS MINS TO ONLY FALL INTO THE LOW-MID 50S ALONG LK SUPERIOR
AROUND IWD TO ONTONAGON AND EAST TO BARAGA/L`ANSE AND MARQUETTE
AREAS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 510 AM EDT SAT MAY 18 2013

NAM SHOWS THE 500 MB RIDGE OVER THE EASTERN U.S. 12Z SUN WITH
TROUGHING IN THE ROCKIES. THE TROUGH MOVES EAST ON SUNDAY AND PUSHES
THE RIDGE INTO THE LOWER GREAT LAKES 12Z MON WHERE THE MOVEMENT
EASTWARD STOPS THROUGH 12Z TUE. NAM HAS SOME DEEPER MOISTURE AND
850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA 12Z SUN ONWARD. GFS
SHOWS ABOUT THE SAME THING AS WELL.

THIS PERIOD LOOKS PRETTY WET STARTING WITH SUN AFTERNOON THROUGH MON
NIGHT. WITH SLOW MOVEMENT OF SYSTEM INTO AND THROUGH THE AREA AND
ALSO A WARM FRONT NEAR AND TO THE SOUTH OF THE AREA...THIS SETS UP
THE CWA FOR A WIDESPREAD AND LONG LIVED RAIN EVENT WITH SOME HEAVY
RAIN POSSIBLE. AM FORECASTING ANYWHERE FROM .67 INCH OF QPF OVER THE
SOUTH...TO 1.15 INCHES OVER THE EAST TO OVER 2 INCHES OF RAIN IN THE
FAR WEST NEAR IRONWOOD FROM SUNDAY AFTERNOON THROUGH MONDAY NIGHT
AND THIS DOES NOT SEEM UNREASONABLE WITH PLENTY OF MOISTURE TO THE
SOUTH OF THE AREA AND SLOW SYSTEM MOVEMENT. FOR THIS REASON...BUMPED
POPS UP A BIT TO LIKELY TO CATEGORICAL FOR MOST OF THE CWA THROUGH
THEN. SHOULD SEE SOME SUNSHINE ON SUNDAY. MADE A FEW ADJUSTMENTS TO
TEMPERATURES BASED ON LAKE BREEZES AND WIND DIRECTIONS AND LOWERED
THEM A BIT NEAR THE GREAT LAKES SHORELINES. OTHER THAN THAT...NO
REAL BIG CHANGES TO THE GOING FORECAST FOR TEMPERATURES OR WEATHER.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW AND TROUGH
IN THE NORTHERN AND CENTRAL PLAINS 12Z TUE WHICH MOVE LITTLE INTO
12Z WED. BY 12Z THU...THE TROUGH AND LOW GET PUSHED A BIT FURTHER
EAST TO THE UPPER GREAT LAKES REGION. THE TROUGH AND LOW MOVE
THROUGH BY 12Z FRI WITH RIDGING BUILDING INTO THE PLAINS LATE ON
FRI. SYSTEM WILL BE SLOW TO MOVE THROUGH THE AREA...SO A COUPLE OF
DAYS OF WIDESPREAD RAIN ARE NOT OUT OF THE QUESTION ALONG WITH
COOLER TEMPERATURES WITH GRADUAL SOUTHWARD MOVEMENT OF THE SYSTEM
AWAY FROM THE AREA. THU INTO FRI...THINGS START TO DRY OUT WITH A
COLD FRONT WELL SOUTH OF THE AREA. TEMPERATURES SLIP TO SLIGHTLY
BELOW NORMAL THIS PERIOD. POPS WILL BE HIGHEST IN THE SOUTH CLOSER
TO A WARM FRONT.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 141 AM EDT SAT MAY 18 2013

EXPECT VFR CONDITIONS/DRY WX TO PERSIST EARLY IN THE TAF PERIOD. BUT
AS A WARM FNT MOVES IN FM THE S...SOME -SHRA/MVFR CIGS WL BE PSBL...
MAINLY AT CMX/IWD WHERE LLVL WARM/MOIST ADVCTN WL BE MOST
PRONOUNCED. FOLLOWING THE WARM FROPA BY THIS AFTN...EXPECT WSHFT TO
THE S AND A RETURN TO PREDOMINANT VFR WX WITH DAYTIME HEATING/
MIXING. THE ONLY EXCEPTION WL BE AT CMX...WHERE A PERSISTENT UPSLOPE
ESE WIND AND MOISTER LLVL AIR WL RESULT IN LINGERING MVFR CONDITIONS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 510 AM EDT SAT MAY 18 2013

HEADING THRU EARLY NEXT WEEK...THE PRESSURE GRADIENT OVER THE UPPER
LAKES WILL SLOWLY TIGHTEN BETWEEN LOW PRESSURE SLOWLY MOVING FROM
THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH PRESSURE
BUILDING IN THE VICINITY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING TO ALMOST 30 KNOTS BY MON AND
MON NIGHT...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE
FUNNELING/CHANNELING WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...KC
MARINE...07

000
FXUS63 KDTX 180739
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
339 AM EDT SAT MAY 18 2013

.SHORT TERM...TODAY AND TONIGHT

MID/UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO THE REGION TODAY
WHILE WE REMAIN ON THE WESTERN EXTENT OF A DOME OF HIGH PRESSURE AT
THE SFC CENTERED OVER EASTERN CANADA. EASTERLY WINDS WILL PERSIST
THROUGH TONIGHT DUE TO THE SFC HIGH. THE CONTINUED FEED OF DRY
CONTINENTAL AIR WILL KEEP DEWPOINTS IN THE 40S ONCE AGAIN. MODEL
SOUNDINGS IN FAIRLY GOOD AGREEMENT WITH THE 00Z DTX SOUNDING WITH
THE DEPTH OF DRY AIR IN THE BOUNDARY LAYER CURRENTLY AROUND 9KFT.
THE 700MB WARM FRONT LIFTED THROUGH FRIDAY AFTERNOON AND MODELS SHOW
THE WEAKER 925 MB FRONT WILL FOLLOW NORTHWARD THROUGH TODAY. HARD TO
FIND ANY ADDITIONAL SUPPORT TO HELP THIS KICK OFF ANY SHOWERS THIS
AFTERNOON. MODELS KEEP MOST OF THE SHOWERS OVER THE OHIO VALLEY
WHERE SFC MOISTURE IS MUCH HIGHER. THE LIKELY RESULT WILL END UP
BEING A LOWERING OF THE CLOUD DECK TO AROUND 6-7KFT. WEAK WAA WILL
ALLOW TEMPS TO REBOUND A FEW MORE DEGREES TODAY INTO THE MID/UPPER
70S WITH COOLER TEMPS FOR AREAS IN THE LAKE SHADOW.

&&

.LONG TERM...SUNDAY THROUGH FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
ON SUNDAY. ALTHOUGH A SURFACE WARM FRONT WILL LIFT NORTH THROUGH THE
CWA EARLY ON SUNDAY...DRY CONDITIONS ARE EXPECTED TO CONTINUE
DESPITE MUCAPE VALUES APPROACHING 1000 J/KG DURING THE AFTERNOON
HOURS GIVEN THE VERY DRY AND IN PLACE AND STABILIZING EFFECT OF
DOWNWARD MOTION FROM THE UPPER LEVEL RIDGE. THE PASSAGE OF THE WARM
FRONT WILL BRING WARMER AIR TO THE REGION...WITH DAYTIME HIGHS
AROUND THE 80 DEGREE MARK AWAY FROM LAKE HURON.

WARM AIR WILL CONTINUE TO STREAM IN BEHIND THE WARM FRONT EARLY IN
THE WORK WEEK AS SOUTHERLY WINDS BRING A MARKED INCREASE IN MOISTURE
ACROSS SOUTHERN MICHIGAN. THE INCREASED MOISTURE AS WELL AS THE
SHIFT EAST IN THE UPPER LEVEL RIDGE WILL BRING AN INCREASE IN RAIN
CHANCES TO SOUTHEAST MICHIGAN AS THE WEEK PROGRESSES. ALTHOUGH AN
UPPER LEVEL LOW WILL SIT OFF TO THE WEST DURING THE EARLY PART OF
THE WEEK...SEVERAL EMBEDDED SHORTWAVES WILL TAKE ADVANTAGE OF THE
INCREASED INSTABILITY OF 1000 TO 2000 J/KG MONDAY AND TUESDAY. THE
UPPER LEVEL DYNAMICS AND INSTABILITY WILL BRING THE POSSIBILITY FOR
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS TO THE AREA. DESPITE THE
DECENT CAPE VALUES...SHEAR WILL BE VERY WEAK IN THE LOW LEVELS WITH
A RATHER UNIMPRESSIVE HODOGRAPH AND MEAGER HELICITY VALUES. MONDAY
LOOKS TO BE THE WARMEST DAY OF THE UPCOMING WEEK WITH HIGH
TEMPERATURES GETTING INTO THE LOWER TO MIDDLE 80S ACROSS MUCH OF THE
CWA.

ALTHOUGH MODEL DIFFERENCES STILL EXIST...THERE APPEARS TO BE MORE
AGREEMENT IN HANDLING THE CUT OFF LOW OUT TO THE WEST AS IT
PROGRESSES EAST DURING THE MIDDLE OF THE WEEK. THE GFS AND ECMWF
SOLUTIONS MERGE THIS LOW WITH THE NORTHERN STREAM LOW OVER HUDSON
BAY...ABSORBING THE LOW AS A POSITIVELY TILTED TROUGH TRACKING
THROUGH THE CENTRAL GREAT LAKES REGION. ALTHOUGH THUNDERSTORMS ARE
STILL POSSIBLE DURING THE MIDDLE OF THE WEEK...THE BEST INSTABILITY
WILL BE WELL TO THE SOUTH. HOWEVER THE SYSTEM WILL HAVE ENOUGH
MOISTURE TO PRODUCE SOME HEAVY RAIN SHOWERS DURING THE MIDDLE OF THE
WEEK AS THE SURFACE LOW TRACKS THROUGH THE SOUTHERN GREAT LAKES
REGION.

CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE LOW LATE IN THE
WEEK...BRINGING DRY CONDITIONS AND MUCH COOLER DAYTIME HIGHS IN THE
60S TO SOUTHEAST MICHIGAN.

&&

.MARINE...

EASTERLY FLOW WILL CONTINUE THROUGH TONIGHT AS WE REMAIN UNDER THE
INFLUENCE OF HIGH PRESSURE OVER CANADA. THE FAVORABLE FETCH WILL
ALLOW WAVES TO BE SLIGHTLY HIGH OVER WESTERN LAKE ERIE...BUT A
DECREASING TREND WILL KEEP THEM BELOW SMALL CRAFT ADVISORY CRITERIA.
WINDS WILL VEER TO SOUTHERLY BY SUNDAY NIGHT BEFORE INCREASING
NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE PLAINS. THIS LOW WILL
BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH AT LEAST WEDNESDAY
AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN SOUTHERLY WINDS BY
MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO NORTHERLY CAN THEN BE
EXPECTED AS A COLD FRONT PUSHES ACROSS AREA WATERS.

&&

.AVIATION...ISSUED 102 AM EDT SAT MAY 18 2013

//DISCUSSION...

STRONG HIGH PRESSURE PARKED ACROSS ERN ONTARIO AND QUEBEC WILL
MAINTAIN A FEED OF LOW LEVEL DRY AIR INTO SE MI UNDER PERSISTENT
EAST-SOUTHEASTERLY WINDS. THIS WILL SUSTAIN CLEAR SKIES BELOW 8000
FT THROUGH SAT AFTERNOON. RESIDUAL SHOWER ACTIVITY IN THE VICINITY
OF MBS WILL CONTINUE TO WANE DURING THE EARLY MORNING HOURS AS
SUBSIDENCE ALOFT ENVELOPS LOWER MI.

//DTW THRESHOLD THREATS...

* NONE.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK
AVIATION.....SC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 180729
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 AM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FAIR AND MILD WEATHER IS ANTICIPATED THIS WEEKEND. A LOW PRESSURE
SYSTEM OVER THE UPPER MIDWEST WILL BRING A PERIOD OF UNSETTLED
WEATHER WITH OCCASIONAL ROUNDS OF RAIN AND THUNDERSTORMS FROM MONDAY
THROUGH WEDNESDAY. FAIR AND COOLER WEATHER IS EXPECTED LATE IN THE
WEEK.

&&

.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT MAY 18 2013

OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE PROBABILITIES
FOR SHOWERS AND STORMS MAINLY FOR MONDAY.

FAIR AND MILD WX IS ANTICIPATED THROUGH THE WEEKEND WITH MAX TEMPS
WELL ITNO THE 70S TO NEAR 80 DEGREES TODAY AND A FEW DEGREES WARMER
THAN THAT FOR SUNDAY.

THERE IS JUST SLIGHT CHC OF A SHOWER THIS AFTN SW OF KGRR WHERE SOME
INSTABILITY WILL DEVELOP. AN OVERALL CONSENSUS OF 00Z SHORT RANGE
GUIDANCE SUGGESTS PROBABILITIES FOR A SHOWER THERE WOULD BE REALLY
LOW.

THE WX PATTERN WILL BECOME MORE UNSETTLED AND ACTIVE BEGINNING
MONDAY... PARTICULARLY IN THE AFTERNOON. WE BOOSTED MAX TEMPS UP BY
SEVERAL DEGREES FOR MONDAY WITH THE EXPECTATION OF A FAIR AMOUNT OF
SUN AND SOUTHERLY FLOW WAA BY THEN.

THIS WILL LEAD TO INCREASING INSTABILITY WITH POTENTIAL FOR SB CAPES
TO REACH 2000-3000 J/KG MONDAY AFTERNOON AND AS THE UPPER RIDGE AXIS
SHIFTS EAST AND SOME PVA BEGINS TO MOVE IN FROM THE SW LATE IN THE
DAY. MOISTURE WILL ALSO BE ON THE INCREASE IN THE SOUTHERLY FLOW WAA
REGIME ALLOWING DEW POINT VALUES TO CLIMB INTO THE 60S. SO THE
THREAT FOR SHOWERS AND STORMS WILL BEGIN TO RAMP UP BEGINNING MONDAY
AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT MAY 18 2013

LONG TERM PERIOD LOOKS TO BE A WET TIME FRAME...AS AN UPPER LOW IN
THE NORTHERN PLAINS SLOWLY WORKS INTO AND THROUGH THE REGION DURING
THIS TIME FRAME. IN FACT...YESTERDAY EVENING/S 7 DAY EXPERIMENTAL
PRECIPITATION PRODUCT FROM WPC WAS INDICATING 1 TO AROUND 2 INCHES
OF RAINFALL ACROSS THE SOUTHWEST QUARTER OF LOWER MI.

A WARM FRONTAL BOUNDARY WILL BE NEARBY OR DRAPED ACROSS THE FORECAST
AREA FOR MUCH OF THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
DURING THIS TIME WE HAVE LIKELY CHANCES (60/70 PCT) FOR
SHOWERS/STORMS FOR MOST OF THE FORECAST AREA.

A DEEP SOUTHERLY FLOW WILL BE IN PLACE EMANATING FROM THE GULF
COAST...WHICH IS SOMETHING WE HAVE LACKED THIS MONTH. PRECIPITABLE
WATER VALUES WILL BE ON THE ORDER OF AN INCH TO AN INCH AND A HALF
INTO MID WEEK.

DIFFICULT TO NAIL DOWN ANY SPECIFIC SEVERE THREAT TIME FRAMES...BUT
MONDAY AFTERNOON AND EVENING AND AGAIN ON WEDNESDAY MAY BE TIMES TO
WATCH. HEATING TO AID IN INSTABILITY WILL BE THE DIFFICULT VARIABLE
TO PINPOINT GIVEN THE AMOUNT OF CLOUDS AND PRECIP AROUND. IF WE CAN
HEAT DURING THE DAYLIGHT HOURS THOUGH INSTABILITY SHOULD BUILD
READILY.

LATE IN THE WEEK THE LOW WILL SLIDE EAST FINALLY AND HIGH PRESSURE
WILL BEGIN TO BUILD IN FROM THE NORTH. HAVE A DRY FORECAST TOWARD
WEEKS END.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1142 PM EDT FRI MAY 17 2013

VFR CIGS/VSBY WILL CONTINUE THROUGH SATURDAY.

THERE ARE A FEW LIGHT RAIN SHOWERS HEADING TOWARD THE MKG TAF SITE
BUT THOSE SHOULD BE GONE 09Z. CONDITIONS WILL REMAIN VFR EVEN WITH
THE SHOWERS.

THERE IS STILL A LOW TO MID LEVEL FEED OF WARM MOIST AIR FROM THE
GULF NORTH THROUGH KENTUCKY THEN OVER THE STATIONARY FRONT NEAR
I-80 THIS EVENING. THAT IS WHAT IS CREATED ALL THOSE LAYERED CLOUDS
WE CAN SEE OUTSIDE. HOWEVER THE FEED OF MOISTURE WEAKENS OVERNIGHT
THEN REDEVELOPS FARTHER TO THE EAST ON SATURDAY. IT STILL LOOKS
LIKE CLEARING LATE IN THE DAY SATURDAY.

&&

.MARINE...
ISSUED AT 330 AM EDT SAT MAY 18 2013

OFFSHORE EASTERLY WINDS WILL RESULT IN MINIMAL WAVE HEIGHTS THIS
WEEKEND. THUNDERSTORMS WILL POSE A HAZARD TO MARINERS MONDAY THROUGH
WEDNESDAY.

&&

.FIRE WEATHER...
ISSUED AT 330 AM EDT SAT MAY 18 2013

FIRE WEATHER CONCERNS ARE FAIRLY MINIMAL DUE TO INCREASING DEW POINT
VALUES AND RELATIVE HUMIDITY VALUES THIS WEEKEND AND FAIRLY LOW WIND
SPEEDS MAINLY UNDER 15 MPH. SEVERAL ROUNDS OF RAIN AND STORMS ARE
EXPECTED MONDAY THROUGH WEDNESDAY.

&&

.HYDROLOGY...
ISSUED AT 330 AM EDT SAT MAY 18 2013

SEVERAL ROUNDS OF SHOWERS AND STORMS ARE EXPECTED MONDAY THROUGH
WEDNESDAY WITH TOTAL RAINFALL AMOUNTS ON AVERAGE IN THAT TIME FRAME
OF AROUND AN INCH TO INCH AND A HALF POSSIBLE WITH LOCALLY HIGHER
AMOUNTS WITH HEAVIER STORMS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...WDM
MARINE...LAURENS
FIRE WEATHER...LAURENS
HYDROLOGY...LAURENS

000
FXUS63 KAPX 180719
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
319 AM EDT SAT MAY 18 2013

.SYNOPSIS...
ISSUED AT 317 AM EDT SAT MAY 18 2013

HIGH PRESSURE WILL EXIT TO THE EAST...ALLOWING FOR WARMER CONDITIONS
ALONG WITH A CHANCE FOR SHOWERS OVER THE WEEKEND. A STORM SYSTEM
CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO THE PLAINS
TODAY...AND INTO THE GREAT LAKES TO START THE WORK WEEK. THIS WILL
GENERATE SHOWERS AND THUNDERSTORMS OVER NORTHERN MICHIGAN BEGINNING
MONDAY AND CONTINUING THROUGH MIDWEEK.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 317 AM EDT SAT MAY 18 2013

ON THE LATEST SURFACE WEATHER MAP...1025 MB HIGH PRESSURE WAS
CENTERED OVER SOUTHEAST ONTARIO WITH 1002 MB LOW PRESSURE ALONG THE
FRONT RANGE OF THE CENTRAL ROCKIES. APX AND SURROUNDING RADARS
SHOWED A FEW LIGHT RAIN SHOWERS SPRINKLED ACROSS PORTIONS OF NORTH
CENTRAL LOWER MICHIGAN. THE MAIN SHORT TERM FORECAST CONCERNS CENTER
AROUND POPS AND HIGH TEMPERATURES TODAY.

TODAY INTO TONIGHT...MORE OF THE SAME WITH SUBTLE WARM FRONT AND
INCREASING THETA-E RIDGING (MOISTURE) ADVECTING INTO THE REGION FROM
THE SOUTHWEST. THE MAIN FORCING/BETTER MOISTURE REMAIN TO OUR WEST
CLOSER TO PARENT UPPER LOW SPINNING ITS WHEELS ACROSS THE ROCKIES.
LOOKING AT MODEL CROSS SECTIONS...LOWER LEVELS REMAIN RATHER DRY
WITH ABUNDANT MID LEVEL MOISTURE (FROM ABOUT 850 TO JUST BELOW 500
MB). SO EXPECT MOSTLY CLOUDY SKIES WITH ISOLATED LIGHT RAIN SHOWERS
MARCHING FROM SOUTHWEST TO NORTHEAST THROUGH THE DAY. MAINLY DRY
TONIGHT WITH PERHAPS JUST A FEW LEFTOVER ISOLATED RAIN SHOWERS
ACROSS THE FAR NORTH. TEMPERATURES ARE A BIT TRICKY TODAY WITH
ABUNDANT CLOUD COVER AND WEAK WARM ADVECTION. HIGHS EXPECTED TO
RANGE FROM THE MIDDLE 60S NORTH TO THE MIDDLE 70S SOUTH. LOWS
TONIGHT RANGING FROM THE MIDDLE 40S TO LOWER 50S.

&&

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM EDT SAT MAY 18 2013

SUNDAY...WILL BE THE BEST WEATHER DAY OF THE WEEKEND. ERN EDGE OF A
WARM FRONT WILL LIFT NORTHWARD INTO UPPER MICHIGAN. SOUTHERLY FLOW
SOUTH OF THE WARM FRONT WILL BOOST TEMPS INTO THE LOW TO MID 70S
ACROSS ERN UPR MICHIGAN AND INTO THE UPPER 70S AND LOWER 80S ACROSS
NRN LWR MICHIGAN. STILL APPEARS SUNDAY WILL BE DRY WITH PARTLY SUNNY
SKIES...AND WILL LIKELY SERVE AS OUR LAST COMPLETELY DRY DAY FOR
MOST OF NEXT WORK WEEK (MORE ON THIS BELOW). AT THIS POINT...SUNDAY
EVENING SHOULD REMAIN DRY...BUT PRECIP CHANCES WILL BEGIN TO
INCREASE ACROSS OUR WRN CWA LATE SUNDAY NIGHT AS AN INITIAL SHORT
WAVE ACCOMPANIED BY BETTER MOISTURE ARRIVE TOWARD DAYBREAK.

MONDAY THRU WEDNESDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE
FROM WEST TO EAST ON MONDAY AS THE WARM FRONT SAGS SOUTHWARD INTO
NRN LWR MICHIGAN. DEVELOPING LOW PRESSURE IN THE PLAINS WILL BEGIN
TO TAP INTO GULF MOISTURE...ADVECTING IT NORTHWARD THRU THE LOWER
AND MID MISSISSIPPI VALLEY AND INTO THE WRN GREAT LAKES. AS THIS
DEEPER MOISTURE BEGINS TO INTERACT WITH THE WARM FRONT AND A SERIES
OF SHORT WAVES RIDING NE THRU MICHIGAN AHEAD OF THE DEEPENING UPPER
LOWER...WAVES OF SHOWERS AND STORMS WILL REMAIN THE RULE BEGINNING
MONDAY AND CONTINUING THRU WEDNESDAY NIGHT. SURFACE AND CLOSED UPPER
LOW BECOME VERTICALLY STACKED...THUS MAKING VERY SLOW EASTWARD
PROGRESS OVER THIS TIME PERIOD...AND THEREFORE KEEPING OUR WEATHER
UNSETTLED THRU MID WEEK (AT LEAST). WARM TEMPS WILL HOLD OVER THE
REGION ON MONDAY BEFORE THE WARM FRONT SAGS SOUTH ON TUESDAY AND
WEDNESDAY. HIGH TEMPS ON MONDAY WILL RANGE FROM AROUND 70 DEGREES
ACROSS ERN UPR MICHIGAN NORTH OF THE WARM FRONT TO THE MID 70S TO
LOWER 80S SOUTH OF THE WARM FRONT. HIGH TEMPS WILL ONLY REACH INTO
THE 60S BOTH TUESDAY AND WEDNESDAY AS THE WARM FRONT CONTINUES TO
DROP SOUTH OF OUR CWA.

THURSDAY AND FRIDAY...SURFACE AND UPPER LOW CENTERS WILL SLOWLY
SLIDE THRU LWR MICHIGAN ON THURSDAY...EXITING EAST TOWARD NEW
ENGLAND BY FRIDAY. SOME SHOWERS WILL LINGER ACROSS OUR CWA THURSDAY
AROUND AND JUST NORTH OF THE SURFACE LOW CENTER...BUT SHOULD COME TO
AN END BY FRIDAY AS DRIER AIR FILTERS INTO THE REGION BEHIND THE
DEPARTING LOW. THE COLDER AIR BEHIND THIS SYSTEM WILL NOT ARRIVE
UNTIL SATURDAY. NEUTRAL TEMP ADVECTION WILL LEND TO HIGH TEMPS
REMAINING IN THE 60S FOR BOTH THURSDAY AND FRIDAY. A FIRST LOOK AT
NEXT WEEKEND LOOKS DRY BUT POTENTIALLY COOLER THAN NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1156 PM EDT FRI MAY 17 2013

VFR.

AS HIGH PRESSURE MOVES OFF TO OUR EAST...SOUTHERLY LOW AND MID
LEVEL FLOW IS SLOWLY PUSHING MORE MOIST AIR INTO THE REGION. SOME
-SHRA CONTINUE IN THE TVC AREA...AND MID CLOUDS ARE WIDESPREAD
SOUTH OF PLN. THE CLOUD COVER AND CHANCE FOR PRECIP WILL LIFT
SLOWLY NORTHWARD DURING THE NIGHT...LEADING TO A MOSTLY CLOUDY
DAY ON SATURDAY (WITH MBL SEEING SOME BREAKS IN THE CLOUD COVER).
HOWEVER...CIGS SHOULD REMAIN COMFORTABLY VFR...AND VSBY
RESTRICTIONS ARE ALSO NOT EXPECTED.

WINDS WILL BE LIGHT/VARIABLE TONIGHT...AND LIGHT FROM THE EAST
SATURDAY.


&&

.MARINE...
ISSUED AT 317 AM EDT SAT MAY 18 2013

SOUTH-SOUTHEAST FLOW SLOWLY INCREASES TODAY THROUGH SUNDAY...AND  A
HANDFUL OF SMALL CRAFT ADVISORIES MAY BE NEEDED AT SOME POINT LATER
IN THE WEEKEND.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...MR
SHORT TERM...AS
LONG TERM...MR
AVIATION...JZ
MARINE...AS

000
FXUS63 KMQT 180543
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
143 AM EDT SAT MAY 18 2013

.UPDATE...
ISSUED AT 728 PM EDT FRI MAY 17 2013

LATEST MODELS HAVE TRENDED DRIER FOR THE OVERNGT FCST FOR UPR MI...
SHOWING MORE IMPRESSIVE H85 MOISTENING ASSOCIATED WITH ADVANCING
WARM FNT FOCUSED W OF UPR MI. GIVEN ESE FLOW OUT OF STUBBORN HUDSON
BAY HI PRES/DRY AIRMASS SHOWN ON THE 12Z APX RAOB...TRIMMED POPS
ACCORDINGLY. ALSO REMOVED MENTION OF TS TNGT AS 18Z NAM SHOWS MUCAPE
THRU 12Z SAT NO HIER THAN 5-50 J/KG.
&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

TRICKY PRECIP FORECAST IN THE SHORT TERM. CURRENTLY...THE CWA SITS
BETWEEN AN UPPER RIDGE OVER MN INTO CENTRAL CANADA AND AN UPPER LOW
OVER ERN QUEBEC. AT THE SFC...A HIGH IS OVER THE NE CWA WITH
DEVELOPING LOW PRESSURE OVER THE WRN PLAIN STATES. DRY AIR
ASSOCIATED WITH THE SFC HIGH HAS HELPED KEEP PRECIP/CLOUDS MOSTLY
S/SW OF THE CWA THIS AFTERNOON...BUT A LARGE ARE OF PRECIP IS
LOCATED N OF A WARM FRONT IN AN AREA OF MOISTURE ADVECTION OVER
CENTRAL WI. THE WARM FROM EXTENDS FROM SRN MN /WHERE CONVECTION HAS
DEVELOPED/ TO NRN IL...WHERE PRECIP IS ALSO BEING SEEN.

THE SFC HIGH SHIFTS SLIGHTLY E OVERNIGHT AS A SFC LOW DEEPENS OVER
THE WRN PLAINS...ALLOWING SLY FLOW TO INCREASE OVER THE CWA...BUT
DRY AIR TO KEEP A GRIP ON THE NERN CWA. THE WARM FRONT WILL MOVE N
INTO THE SW CWA AROUND 03Z SAT...FINALLY MOVING TO THE NE CWA BY 00Z
SUN. MODELS ARE ALL OVER THE PLACE WITH QPF LIKELY DUE TO CONVECTIVE
FEEDBACK...AND MANY DO NOT EVEN INITIALIZE WELL WITH QPF. SO
POPS/QPF/WEATHER ARE PRETTY UNCERTAIN LATER THIS EVENING INTO
SAT...BUT THERE ARE SOME THINGS WITH THE PRECIP THAT DO APPEAR MORE
CERTAIN. THE BEST MOISTURE ADVECTION/INSTABILITY WILL BE OVER THE
FAR WRN CWA CLOSER TO THE SFC LOW AND STRONGER SLY FLOW/LOW LEVEL
JET. KEPT HIGHEST POPS OVER THE W...WITH CHANCE POPS OVER THE
CENTRAL AND E CWA...AND ONLY SLIGHT CHANCE POPS OVER THE ERN CWA.
ANOTHER COMPLICATING FACTOR FOR PRECIP TONIGHT IS THE QUESTION ABOUT
CONVECTION DEVELOPING TO OUR S AND CUTTING OFF MOISTURE FLOW. THIS
MAY ACT TO FURTHER REDUCE PRECIP CHANCES...ESPECIALLY OVER THE
CENTRAL AND ERN CWA. EVEN WITH INCREASING LOW LEVEL TEMPS TONIGHT
INTO SAT...HIGHS ON SAT SHOULD NOT BE ALL THAT MUCH HIGHER THAN
TODAY IN MOST LOCATIONS DUE TO INCREASED CLOUD COVER SAT.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

SAT NIGHT AND SUNDAY...MODELS SUGGEST THAT MID/UPPER LEVEL RIDGING
WILL PREVAIL DOWNSTREAM FROM THE TROUGH DIGGING INTO THE PLAINS.
EXPECT THAT THE AREA WILL REMAIN MAINLY DRY AS THE MOISTURE AXIS
REMAINS WEST OF THE CWA AND THE THE FOCUS FOR STRONGER ISENTROPIC
LIFT WITH THE 850-700 MB FRONT REMAINS WELL TO THE NORTH. POPS
CLIMB SLIGHTLY SUNDAY AFTERNOON OVER THE WEST AS THE TROUGH SHIFTS
TO THE EAST AND THE POTENTIAL FOR WEAK SHRTWVS LIFTING TOWARD THE
REGION INCREASES. MUCAPE VALUES TO NEAR 1K J/KG WILL ALSO SUPPORT
POTENTIAL FOR TSRA.

SUN NIGHT INTO MON...THE ECMWF/GFS/GEM WERE IN GOOD AGREEMENT WITH
THE POSITION OF THE DEVELOPING CLOSE MID LEVEL LOW AND SFC LOW FROM
ERN NEBRASKA TO THE SW CORNER OF MN. THIS WILL ALLOW ENOUGH GULF
MOISTURE INFLOW TO PUSH PWAT VALUES TO NEAR 1.5 INCHES (NEAR 200 PCT
OF NORMAL). THE ABUNDANT MOISTURE ALONG WITH INCREASING FORCING FOR
ASCENT WITH UPPER LEVEL DIV AND 700-300 MB QVECTOR CONV AHEAD OF THE
LOW WILL SUPPORT LIKELY POPS SPREADING INTO THE CWA SUNDAY NIGHT AND
LINGERING THROUGH MONDAY. SCT TSRA ARE ALSO EXPECTED WITH THE
MAINLY ELEVATED CONVECTION NORTH OF THE SFC WARM FRONT MOVING TOWARD
NRN WI.

TUE-FRI...UNCERTAINTY INCREASES AS MODEL SHOW LARGER DIFFERENCES IN
HANDLING THE THE SLOW MOVING MID LEVEL LOW/TROUGH. THE 12Z ECMWF AND GEM
SUGGEST THAT THE LOW WILL ONLY SLOWLY WEAKEN AND SLIDE TO THE
EAST...KEEPING PCPN CHANCES IN THE AREA THROUGH THU WHILE THE 12Z
GFS AND 00Z ECMWF PUSH THE TROUGH AND FRONT TO THE SOUTH AS
STRENGTHENING NRN STREAM FLOW DEVELOPS FROM NRN ONTARIO INTO THE NRN
LAKES.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 141 AM EDT SAT MAY 18 2013

EXPECT VFR CONDITIONS/DRY WX TO PERSIST EARLY IN THE TAF PERIOD. BUT
AS A WARM FNT MOVES IN FM THE S...SOME -SHRA/MVFR CIGS WL BE PSBL...
MAINLY AT CMX/IWD WHERE LLVL WARM/MOIST ADVCTN WL BE MOST
PRONOUNCED. FOLLOWING THE WARM FROPA BY THIS AFTN...EXPECT WSHFT TO
THE S AND A RETURN TO PREDOMINANT VFR WX WITH DAYTIME HEATING/
MIXING. THE ONLY EXCEPTION WL BE AT CMX...WHERE A PERSISTENT UPSLOPE
ESE WIND AND MOISTER LLVL AIR WL RESULT IN LINGERING MVFR CONDITIONS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...KC
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...KC
MARINE...TITUS

000
FXUS63 KDTX 180502
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
102 AM EDT SAT MAY 18 2013


.AVIATION...

//DISCUSSION...

STRONG HIGH PRESSURE PARKED ACROSS ERN ONTARIO AND QUEBEC WILL
MAINTAIN A FEED OF LOW LEVEL DRY AIR INTO SE MI UNDER PERSISTENT
EAST-SOUTHEASTERLY WINDS. THIS WILL SUSTAIN CLEAR SKIES BELOW 8000
FT THROUGH SAT AFTERNOON. RESIDUAL SHOWER ACTIVITY IN THE VICINITY
OF MBS WILL CONTINUE TO WANE DURING THE EARLY MORNING HOURS AS
SUBSIDENCE ALOFT ENVELOPS LOWER MI.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 833 PM EDT FRI MAY 17 2013

UPDATE...

A UPDATE TO THE GRIDS/ZONES WAS ISSUED TO INCREASE THE CHANCES OF
LIGHT RAIN ACROSS THE SAGINAW VALLEY AND THUMB REGION. MID
TROPOSPHERIC FRONTOGENESIS HAS BEEN RATHER PERSISTENT AND HAS
RESULTED IN SEVERAL OBS REPORTING LIGHT RAIN OR SPRINKLES. THE
FGEN SHOULD PERSIST THROUGH 06Z TONIGHT BEFORE WANING LATE AS
SHORT WAVE RIDGING OVERSPREADS LOWER MI CAUSING THE MID LEVEL
FRONTAL CIRCULATION TO WEAKEN.

PREV DISCUSSION...ISSUED 329 PM EDT FRI MAY 17 2013

SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL MOISTURE IN PLACE OVER SOUTHEAST MICHIGAN CONTINUES
TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY THE LAKE
AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL COME TOWARD
MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KAPX 180356
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1156 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 405 PM EDT FRI MAY 17 2013

AS HIGH PRESSURE EXITS TOWARD THE NORTH ATLANTIC...NORTHERN
MICHIGAN`S WEATHER WILL GROW INCREASINGLY UNSETTLED INTO THE
WEEKEND...WITH SCATTERED SHOWERS POSSIBLE MAINLY ON SATURDAY. A
STORM SYSTEM CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO
THE PLAINS ON SATURDAY AND INTO THE GREAT LAKES TO START THE WORK
WEEK. THIS WILL GENERATE SHOWERS AND THUNDERSTORMS WHILE CONTINUING
EXTREMELY WARM TEMPERATURES OVER NORTHERN MICHIGAN INTO MIDWEEK.

&&

.UPDATE...
ISSUED AT 1005 PM EDT FRI MAY 17 2013

SPRINKLES AND -SHRA CONTINUE IN FAR S CENTRAL AND SE
SECTIONS...WILL CONTINUE TO STRETCH THIS PRECIP OUT A LITTLE
LONGER INTO THE NIGHT. SPOTTY -SHRA HAVE REDEVELOPED AS EXPECTED
WEST OF TVC...AS A SUBTLE 850MB WARM FRONT BEGINS TO DEVELOP. THIS
WILL LIFT SLOWLY NORTHWARD UP LAKE MI...AND WILL START TO FADE OUT
OF EXISTENCE TOWARD 12Z. THE AREA OF -SHRA FORMATION WILL SLOWLY
CREEP NE-WARD WITH TIME OVERNIGHT...AND CLOUD COVER WILL MAKE
NORTHWARD PROGRESS ALONG WITH IT. AGAIN...THIS PROCESS MAY BE A
LITTLE SLOWER THAN EARLIER PROGGED. TEMPS NEED ONLY MINOR TWEAKS.

UPDATE ISSUED AT 718 PM EDT FRI MAY 17 2013

PRECIP IS LINGERING BUT GETTING LIGHTER IN SOUTH OF M-72. SOME
TWEAKS MADE TO THE MID-EVENING POPS...TO BOOST IN THE FAR SOUTH
AND TO ERODE ALONG THE NORTHERN EDGE. CLOUD COVER HAS BEEN
DECREASING ALONG THE M-32 CORRIDOR...AND HAVE DECREASED EVENING
CLOUD COVER FROM THERE NORTH. WITH WARM/MOIST ADVECTION EXPANDING
NE WITH TIME TONIGHT...THIS CLEARING WILL BE TEMPORARY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RATHER INTERESTING FORECAST UNFOLDING THIS AFTERNOON...WITH REMNANTS
OF UPSTREAM EARLY MORNING MCS SPREADING ALONG THE M-55 CORRIDOR...
IN-SPITE OF PERSISTENT LOW LEVEL DRYING. WIDESPREAD LIGHT RAINS THE
RESULT SOUTH OF GRAND TRAVERSE BAY...WITH DEEP LAYER DRY WEDGE AND
LACK OF FORCING MAINTAINING DRY WEATHER ELSEWHERE. TEMPERATURES HAVE
RESPONDED ACCORDINGLY...WITH THE "WARMEST" READINGS WELL INTO THE
60S ACROSS THE NORTH...WITH THOSE EXPERIENCING RAIN STUCK MAINLY IN
THE 50S. FORECAST CONCERNS THROUGH SATURDAY CENTER ON ADDITIONAL
RAIN CHANCES AS WELL AS CLOUD AND TEMPERATURE TRENDS.

OVERNIGHT CONFIDENCE HAS TAKEN A REMARKABLE DOWNWARD TREND AFTER
TODAY`S EVENTS. BEST GUESS SUGGESTS ONGOING ACTIVITY WILL WANE
THROUGH THE AFTERNOON...WITH INCREASING FOCUS FOR RENEWED ACTIVITY
FURTHER TO OUR NORTHWEST WHERE MOISTURE/MASS CONVERGENCE IS
MAXIMIZED ON NOSE OF LOW LEVEL JET AND ALONG ELEVATED WARM FRONT.
DESPITE SOME LOW LEVEL MOISTENING...FEEL BEST BET FOR ANY RAINS
REACHING THE SURFACE WILL REMAIN ACROSS WISCONSIN INTO WESTERN UPPER
MICHIGAN THROUGH THE OVERNIGHT. NORTHEAST BOWING THETA-E RIDGE MAY
SUPPORT SOME LIGHT SHOWERS ADVANCING EAST FROM GENERATION
REGION...PERHAPS BRINGING SOME SCATTERED LIGHT SHOWERS TO PARTS OF
THE AREA (ESPECIALLY THE WESTERN HALF WHERE LOW LEVEL MOISTURE WILL
BE DEEPER). WILL CONTINUE TO WORD AS SUCH...KEEPING JUST LOW END
MENTION FOR LIGHT SHOWERS SLOWLY ADVANCING NORTH WITH TIME. PLENTY
OF CLOUDS TONIGHT SUPPORTS MUCH WARMER TEMPERATURES THAN THOSE
OBSERVED LAST NIGHT...WITH WIDESPREAD READINGS IN THE 40S.

PERHAPS SOME LINGERING LIGHT SHOWERS SATURDAY MORNING...OTHERWISE A
MAINLY DRY DAY IS EXPECTED AS MID LEVEL RIDGING BUILDS OVERHEAD AND
FOCUS FOR ADDITIONAL SHOWERS SHUNTS EVEN FURTHER NORTHWEST. CLOUDS
SHOULD DOMINATE EARLY...WITH TRENDS SUPPORTING SOME AFTERNOON
CLEARING SPREADING IN FROM THE SOUTHWEST. TEMPERATURES HIGHLY
DEPENDENT ON JUST HOW AGGRESSIVE CLEARING BECOMES. A BLEND BETWEEN
COOL GUIDANCE AND INHERITED WARM READINGS SEEMS AS GOOD A STARTING
POINT AS ANY...GIVING HIGHS IN THE UPPER 60S AND LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RECENT TRENDS: TEMPERATURES...STARTING TO RECOVER FROM RECENT COOL
SPELL...3-4C BELOW NORMAL LAST 7 DAYS AND NEAR TO A LITTLE (1-2C)
ABOVE NORMAL FOR THE MONTH OF MAY (WESTERN AND LOWER GREAT LAKES/NEW
ENGLAND WARMTH...COOL IN BETWEEN AND ACROSS THE SOUTHEAST AND GULF
COAST.  PRECIPITATION/HYDROLOGY...BEEN DRIER PAST COUPLE OF DAYS...
PRECIP LAST 7 DAYS 150-300 PERCENT NORMAL EAST OF I-75...MUCH DRIER
ACROSS EASTERN UPPER AND WEST OF US-131 CORRIDOR.  MONTH-TO-DATE
BELOW NORMAL PRECIP EXCEPT SMALL AREA OF NORTHEAST LOWER CENTERED
AROUND ALPENA (SUBSTANTIALLY DRIER DOWNSTATE).  30 DAY STANDARDIZED
PRECIP INDEX MOSTLY NEAR NORMAL.  SOIL MOISTURE ABOVE AVERAGE ACROSS
THE FORECAST AREA...MEAN STREAMFLOWS RUNNING NEAR TO ABOVE NORMAL ON
AREA RIVERS.

LARGE SCALE PATTERN/FORECAST: PROGRESSIVE 5 WAVE HEMISPHERIC PATTERN
WITH LONG WAVE TROUGHS OVER EASTERN CANADA/NEW ENGLAND AND THE
NORTHEAST PACIFIC.  PACIFIC HEIGHT FALLS MOVING ONTO THE WEST COAST
WITH A GRADUAL AMPLIFYING OF THE PATTERN IN RESPONSE...WITH RIDGING
BUILDING ACROSS THE NORTHERN PLAINS/CANADIAN PRAIRIES WITH A REMNANT
CLOSED LOW STUCK BENEATH THE RIDGE MOVING INTO THE TENNESSEE
VALLEY.  GOING FORWARD...SPLIT IN THE FLOW PATTERN EXPECTED TO
DEVELOP OUT WEST AS WESTERN TROUGH CROSSES THE ROCKY MOUNTAINS AND
INTO THE NATION`S MIDSECTION EARLY NEXT WEEK WHILE UPPER HIGH
DEVELOPS OVER THE CANADIAN PRAIRIES IN A BIT OF A SMALL SCALE
BLOCKING PATTERN.  QUASI-EAST/WEST ORIENTED FRONTAL BOUNDARY RUNNING
FROM THE NORTHERN PLAINS ACROSS THE MID MISSISSIPPI VALLEY/OHIO
VALLEY THIS AFTERNOON WILL BE A FOCUS FOR PRECIPITATION DEVELOPMENT
OVER THE COMING DAYS...WITH THE WESTERN PORTION OF THE FRONT GETTING
PUSHED NORTHWARD IN RESPONSE TO FALLING PRESSURES TO THE LEE OF THE
ROCKIES.  EVENTUALLY...THIS FRONT MERGES WITH A COLD FRONT WITHIN
THE NORTHERN BRANCH FOLDING IN FROM THE NORTH ON MONDAY AS UPPER
LEVEL ENERGY PUSHES INTO THE MIDWEST. SO TRYING TO DISCERN RAIN
CHANCES OVER THE COMING DAYS AS THESE FEATURES COME TOGETHER WILL BE
THE MAIN WEATHER CONCERN INTO EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH MONDAY: SHORT WAVE RIDGING WILL BUILD INTO
THE UPPER LAKES SATURDAY NIGHT...WITH PERSISTENT LOW/MID LEVEL WARM
ADVECTION AS NORTHERN MICHIGAN SHOULD STILL BE ON THE COOL SIDE OF
THE OHIO VALLEY BAROCLINIC ZONE.  SHOULD STILL BE SOME CLOUDS AROUND
SATURDAY NIGHT WITHIN WARM ADVECTION/ISENTROPIC ASCENT...PROBABLY
CAN`T RULE OUT SOME SPOTTY LIGHT RAIN SHOWERS ESPECIALLY THE FARTHER
NORTH ONE GOES.  BUT THE GENERAL TREND OF IMPROVING CONDITIONS INTO
SUNDAY STILL LOOKS REASONABLE.  LOOKS LIKE BOUNDARY TO THE SOUTH
WILL TEND TO WEAKEN/MIX OUT SUNDAY...WITH AN INCREASE OF LOW LEVEL
MOISTURE INTO LOWER MICHIGAN WITH SOUTHERLY WINDS.  PROBABLY A
LITTLE TOO MOIST IN SOME OF THE GUIDANCE (E.G., NAM-WRF)...THUS WILL
KEEP THE FORECAST DRY AS IS CURRENTLY AND NOT INTRODUCE DIURNALLY
DRIVEN CONVECTIVE SHOWERS INTO THE FORECAST FOR SUNDAY AFTERNOON.
EXPECT SUNDAY AFTERNOON TO BE WARM WITH HIGHS WELL INTO THE 70S/
AROUND 80.

DEVELOPING/STRENGTHENING BAROCLINIC ZONE TO THE NORTH OF MICHIGAN
FORECAST TO BECOME BETTER ORGANIZED SUNDAY NIGHT INTO MONDAY AS IT
PRESSES SOUTH INTO THE UPPER PENINSULA AND POSSIBLY NUDGING INTO
NORTHERN LOWER MICHIGAN (AIDED BY COOL LAKE BREEZE CIRCULATION??).
POTENTIALLY ANOTHER WARM AND MORE HUMID AFTERNOON MONDAY...FORECAST
SOUNDINGS HAVE A LITTLE MORE CAPPY LOOK TO THEM BUT WILL HANG ONTO A
CHANCE OF THUNDERSTORMS FOCUSED MAINLY ON THE DIURNAL CYCLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): UNSETTLED WEATHER
THROUGH MIDWEEK AS BOUNDARY CONTINUES TO SAG INTO THE LOWER
PENINSULA...WITH CHANCES FOR THUNDERSTORMS BOTH TUESDAY AND
WEDNESDAY.  IF THE FRONT CAN CLEAR THE AREA WEDNESDAY NIGHT SHOULD
BE ABLE TO DRY THINGS OUT HEADING INTO THURSDAY/FRIDAY...BUT NOT
CERTAIN ABOUT HOW QUICKLY UPPER WAVE WILL MOVE OUT AND SUSPECT THAT
IT WILL BE SLOWER THAN DEPICTED BY THE GFS.  SO WILL SPLIT THE
DIFFERENCE HERE...DRAGGING POPS INTO THURSDAY THEN GOING DRY FOR
FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1156 PM EDT FRI MAY 17 2013

VFR.

AS HIGH PRESSURE MOVES OFF TO OUR EAST...SOUTHERLY LOW AND MID
LEVEL FLOW IS SLOWLY PUSHING MORE MOIST AIR INTO THE REGION. SOME
-SHRA CONTINUE IN THE TVC AREA...AND MID CLOUDS ARE WIDESPREAD
SOUTH OF PLN. THE CLOUD COVER AND CHANCE FOR PRECIP WILL LIFT
SLOWLY NORTHWARD DURING THE NIGHT...LEADING TO A MOSTLY CLOUDY
DAY ON SATURDAY (WITH MBL SEEING SOME BREAKS IN THE CLOUD COVER).
HOWEVER...CIGS SHOULD REMAIN COMFORTABLY VFR...AND VSBY
RESTRICTIONS ARE ALSO NOT EXPECTED.

WINDS WILL BE LIGHT/VARIABLE TONIGHT...AND LIGHT FROM THE EAST
SATURDAY.

&&

.MARINE...
ISSUED AT 405 PM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TONIGHT WITH NO
MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES SATURDAY
THROUGH SUNDAY AND A HANDFUL OF SMALL CRAFT ADVISORIES MAY BE
NEEDED AT THAT TIME.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KAB
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...JZ
MARINE...MSB

000
FXUS63 KDTX 180349
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1149 PM EDT FRI MAY 17 2013


.AVIATION...

//DISCUSSION...

STRONG HIGH PRESSURE PARKED ACROSS ERN ONTARIO AND QUEBEC WILL
MAINTAIN A FEED OF LOW LEVEL DRY AIR INTO SE MI UNDER PERSISTENT
EAST-SOUTHEASTERLY WINDS. THIS WILL SUSTAIN CLEAR SKIES BELOW 8000
FT THROUGH SAT AFTERNOON. RESIDUAL SHOWER ACTIVITY IN THE VICINITY
OF MBS WILL CONTINUE TO WANE DURING THE EARLY MORNING HOURS AS
SUBSIDENCE ALOFT ENVELOPS LOWER MI.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 833 PM EDT FRI MAY 17 2013

UPDATE...

A UPDATE TO THE GRIDS/ZONES WAS ISSUED TO INCREASE THE CHANCES OF
LIGHT RAIN ACROSS THE SAGINAW VALLEY AND THUMB REGION. MID
TROPOSPHERIC FRONTOGENESIS HAS BEEN RATHER PERSISTENT AND HAS
RESULTED IN SEVERAL OBS REPORTING LIGHT RAIN OR SPRINKLES. THE
FGEN SHOULD PERSIST THROUGH 06Z TONIGHT BEFORE WANING LATE AS
SHORT WAVE RIDGING OVERSPREADS LOWER MI CAUSING THE MID LEVEL
FRONTAL CIRCULATION TO WEAKEN.

PREV DISCUSSION...ISSUED 329 PM EDT FRI MAY 17 2013

SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL MOISTURE IN PLACE OVER SOUTHEAST MICHIGAN CONTINUES
TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY THE LAKE
AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL COME TOWARD
MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 180344
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1144 PM EDT FRI MAY 17 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 253 PM EDT FRI MAY 17 2013

A LOW PRESSURE SYSTEM DEVELOPING IN COLORADO WILL TRACK SLOWLY
TOWARD MICHIGAN THROUGH EARLY NEXT WEEK. SOUTHEAST WINDS OUT AHEAD
OF THIS SYSTEM WILL LEAD TO A WARMING TREND. ALSO MOISTURE WILL BE
ON THE INCREASE OVER TIME AND THE WEATHER WILL TURN UNSETTLED FOR
EARLY NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 253 PM EDT FRI MAY 17 2013

THE MAIN CHALLENGE DEALS WITH THE CHANCES FOR SHOWERS TONIGHT.

THE PERSISTENT AREA OF SHOWERS CONTINUES TO IMPACT THE REGION
MAINLY NORTH OF A MUSKEGON TO ALMA LINE. OTHER SHOWERS WERE
DEVELOPING OVER LAKE MI AND WERE TRACKING NORTHEAST. THE PV
ANOMALY RESPONSIBLE FOR THE SHOWERS WAS WEAKENING. IR IMAGERY
SHOWS THE CLOUD TOPS WARMING AND RADAR TRENDS SHOW THE
PRECIPITATION WEAKENING. WILL FEATURE AN EVENING PERIOD IN THE
FORECAST TO COVER THE SHOWERS ONGOING AND THEN FEATURE A LOWER POP
FOR TONIGHT.

I CONSIDERED ADDING AN AFTERNOON THUNDERSTORM TO THE FORECAST FOR
SATURDAY FOR LOCATIONS SOUTHWEST OF GRAND RAPIDS. WEAK FORCING BUT
SOME INSTABILITY IS EXPECTED. LIFTED INDEX VALUES DROP DOWN TO -2
TO -4 DEG C. THE INSTABILITY IS NOT PROGGED TO BE AS STRONG AS
TODAYS VALUES DOWN IN INDIANA WHERE THUNDERSTORMS WERE DEVELOPING.
SO WILL KEEP IT DRY FOR NOW.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 253 PM EDT FRI MAY 17 2013

FORECAST CONCERNS DURING THE LONG TERM DEAL WITH THUNDERSTORM
POTENTIAL. MEDIUM RANGE MODELS ARE LOOKING INCREASINGLY WET DURING
THE FIRST HALF OF NEXT WEEK. A SLOW MOVING NORTHERN PLAINS LOW WILL
DRIFT EAST NEXT WEEK. A STATIONARY FRONT IS PROGD TO EXTEND EWD FROM
THE LOW THROUGH NRN WISCONSIN INTO NRN LWR. WE/LL BE IN THE WARM
SECTOR SOUTH OF THE ACTIVE FRONTAL BOUNDARY. SHORT WAVES EJECTING
FROM THE ASSOCIATED UPPER LOW WILL RESULT IN SCT TO NUMEROUS
THUNDERSTORMS MON-WED. PLENTY OF INSTABILITY WILL EXIST WITH LI/S
NEAR -8C AND SBCAPE IN THE 2K-3K J/KG RANGE. SHEAR VALUES AROUND 40
KTS SUGGESTS STRONG STORMS POSSIBLE BUT NOT TOTALLY SOLD ON THE SVR
POTENTIAL YET. MOISTURE SHOULDN/T BE A LIMITING FACTOR AS A 30KT SW
FLOW WILL DRAW MOISTURE NWD FROM THE GULF. CONVECTIVE INITIATION
WILL LIKELY DEPEND ON MULTITUDE OF SHORT WAVES MOVING ACROSS THE
GREAT LAKES.

THE CONVECTIVE THREAT WILL DIMINISH AFTER WEDNESDAY AS THE SFC LOW
MOVES EAST OF THE CWA AND COOLER AND MORE STABLE NE WINDS DEVELOP.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1142 PM EDT FRI MAY 17 2013

VFR CIGS/VSBY WILL CONTINUE THROUGH SATURDAY.

THERE ARE A FEW LIGHT RAIN SHOWERS HEADING TOWARD THE MKG TAF SITE
BUT THOSE SHOULD BE GONE 09Z. CONDITIONS WILL REMAIN VFR EVEN WITH
THE SHOWERS.

THERE IS STILL A LOW TO MID LEVEL FEED OF WARM MOIST AIR FROM THE
GULF NORTH THROUGH KENTUCKY THEN OVER THE STATIONARY FRONT NEAR
I-80 THIS EVENING. THAT IS WHAT IS CREATED ALL THOSE LAYERED CLOUDS
WE CAN SEE OUTSIDE. HOWEVER THE FEED OF MOISTURE WEAKENS OVERNIGHT
THEN REDEVELOPS FARTHER TO THE EAST ON SATURDAY. IT STILL LOOKS
LIKE CLEARING LATE IN THE DAY SATURDAY.

&&

.MARINE...
ISSUED AT 253 PM EDT FRI MAY 17 2013

GENERAL OFFSHORE FLOW WILL KEEP WAVE HEIGHTS TO A MINIMUM.
PRESSURE GRADIENT REMAINS RELATIVELY WEAK...SO WIND TO STAY UNDER SCA.


&&

.FIRE WEATHER...
ISSUED AT 253 PM EDT FRI MAY 17 2013

HUMIDITY LEVELS SHOULD DROP OFF INTO THE 25 TO 30 PERCENT RANGE
SOUTH OF GRAND RAPIDS THROUGH ABOUT 23Z. THIS COMBINED WITH TEMPS
IN THE 70S WILL LEAD TO AN ELEVATED FIRE DANGER RISK.

&&

.HYDROLOGY...
ISSUED AT 253 PM EDT FRI MAY 17 2013

LOCALIZED SHOWERS NOT CREATING MUCH QPF THIS
AFTERNOON...GENERALLY UNDER A TENTH OF AN INCH. A HIGHER RISK FOR
HEAVIER SHOWERS WILL ARRIVE BY MONDAY AS GULF MOISTURE WORKS ITS
WAY INTO THE AREA.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...WDM
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KAPX 180205
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1005 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 405 PM EDT FRI MAY 17 2013

AS HIGH PRESSURE EXITS TOWARD THE NORTH ATLANTIC...NORTHERN
MICHIGAN`S WEATHER WILL GROW INCREASINGLY UNSETTLED INTO THE
WEEKEND...WITH SCATTERED SHOWERS POSSIBLE MAINLY ON SATURDAY. A
STORM SYSTEM CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO
THE PLAINS ON SATURDAY AND INTO THE GREAT LAKES TO START THE WORK
WEEK. THIS WILL GENERATE SHOWERS AND THUNDERSTORMS WHILE CONTINUING
EXTREMELY WARM TEMPERATURES OVER NORTHERN MICHIGAN INTO MIDWEEK.

&&

.UPDATE...
ISSUED AT 1005 PM EDT FRI MAY 17 2013

SPRINKLES AND -SHRA CONTINUE IN FAR S CENTRAL AND SE
SECTIONS...WILL CONTINUE TO STRETCH THIS PRECIP OUT A LITTLE
LONGER INTO THE NIGHT. SPOTTY -SHRA HAVE REDEVELOPED AS EXPECTED
WEST OF TVC...AS A SUBTLE 850MB WARM FRONT BEGINS TO DEVELOP. THIS
WILL LIFT SLOWLY NORTHWARD UP LAKE MI...AND WILL START TO FADE OUT
OF EXISTENCE TOWARD 12Z. THE AREA OF -SHRA FORMATION WILL SLOWLY
CREEP NE-WARD WITH TIME OVERNIGHT...AND CLOUD COVER WILL MAKE
NORTHWARD PROGRESS ALONG WITH IT. AGAIN...THIS PROCESS MAY BE A
LITTLE SLOWER THAN EARLIER PROGGED. TEMPS NEED ONLY MINOR TWEAKS.

UPDATE ISSUED AT 718 PM EDT FRI MAY 17 2013

PRECIP IS LINGERING BUT GETTING LIGHTER IN SOUTH OF M-72. SOME
TWEAKS MADE TO THE MID-EVENING POPS...TO BOOST IN THE FAR SOUTH
AND TO ERODE ALONG THE NORTHERN EDGE. CLOUD COVER HAS BEEN
DECREASING ALONG THE M-32 CORRIDOR...AND HAVE DECREASED EVENING
CLOUD COVER FROM THERE NORTH. WITH WARM/MOIST ADVECTION EXPANDING
NE WITH TIME TONIGHT...THIS CLEARING WILL BE TEMPORARY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RATHER INTERESTING FORECAST UNFOLDING THIS AFTERNOON...WITH REMNANTS
OF UPSTREAM EARLY MORNING MCS SPREADING ALONG THE M-55 CORRIDOR...
IN-SPITE OF PERSISTENT LOW LEVEL DRYING. WIDESPREAD LIGHT RAINS THE
RESULT SOUTH OF GRAND TRAVERSE BAY...WITH DEEP LAYER DRY WEDGE AND
LACK OF FORCING MAINTAINING DRY WEATHER ELSEWHERE. TEMPERATURES HAVE
RESPONDED ACCORDINGLY...WITH THE "WARMEST" READINGS WELL INTO THE
60S ACROSS THE NORTH...WITH THOSE EXPERIENCING RAIN STUCK MAINLY IN
THE 50S. FORECAST CONCERNS THROUGH SATURDAY CENTER ON ADDITIONAL
RAIN CHANCES AS WELL AS CLOUD AND TEMPERATURE TRENDS.

OVERNIGHT CONFIDENCE HAS TAKEN A REMARKABLE DOWNWARD TREND AFTER
TODAY`S EVENTS. BEST GUESS SUGGESTS ONGOING ACTIVITY WILL WANE
THROUGH THE AFTERNOON...WITH INCREASING FOCUS FOR RENEWED ACTIVITY
FURTHER TO OUR NORTHWEST WHERE MOISTURE/MASS CONVERGENCE IS
MAXIMIZED ON NOSE OF LOW LEVEL JET AND ALONG ELEVATED WARM FRONT.
DESPITE SOME LOW LEVEL MOISTENING...FEEL BEST BET FOR ANY RAINS
REACHING THE SURFACE WILL REMAIN ACROSS WISCONSIN INTO WESTERN UPPER
MICHIGAN THROUGH THE OVERNIGHT. NORTHEAST BOWING THETA-E RIDGE MAY
SUPPORT SOME LIGHT SHOWERS ADVANCING EAST FROM GENERATION
REGION...PERHAPS BRINGING SOME SCATTERED LIGHT SHOWERS TO PARTS OF
THE AREA (ESPECIALLY THE WESTERN HALF WHERE LOW LEVEL MOISTURE WILL
BE DEEPER). WILL CONTINUE TO WORD AS SUCH...KEEPING JUST LOW END
MENTION FOR LIGHT SHOWERS SLOWLY ADVANCING NORTH WITH TIME. PLENTY
OF CLOUDS TONIGHT SUPPORTS MUCH WARMER TEMPERATURES THAN THOSE
OBSERVED LAST NIGHT...WITH WIDESPREAD READINGS IN THE 40S.

PERHAPS SOME LINGERING LIGHT SHOWERS SATURDAY MORNING...OTHERWISE A
MAINLY DRY DAY IS EXPECTED AS MID LEVEL RIDGING BUILDS OVERHEAD AND
FOCUS FOR ADDITIONAL SHOWERS SHUNTS EVEN FURTHER NORTHWEST. CLOUDS
SHOULD DOMINATE EARLY...WITH TRENDS SUPPORTING SOME AFTERNOON
CLEARING SPREADING IN FROM THE SOUTHWEST. TEMPERATURES HIGHLY
DEPENDENT ON JUST HOW AGGRESSIVE CLEARING BECOMES. A BLEND BETWEEN
COOL GUIDANCE AND INHERITED WARM READINGS SEEMS AS GOOD A STARTING
POINT AS ANY...GIVING HIGHS IN THE UPPER 60S AND LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RECENT TRENDS: TEMPERATURES...STARTING TO RECOVER FROM RECENT COOL
SPELL...3-4C BELOW NORMAL LAST 7 DAYS AND NEAR TO A LITTLE (1-2C)
ABOVE NORMAL FOR THE MONTH OF MAY (WESTERN AND LOWER GREAT LAKES/NEW
ENGLAND WARMTH...COOL IN BETWEEN AND ACROSS THE SOUTHEAST AND GULF
COAST.  PRECIPITATION/HYDROLOGY...BEEN DRIER PAST COUPLE OF DAYS...
PRECIP LAST 7 DAYS 150-300 PERCENT NORMAL EAST OF I-75...MUCH DRIER
ACROSS EASTERN UPPER AND WEST OF US-131 CORRIDOR.  MONTH-TO-DATE
BELOW NORMAL PRECIP EXCEPT SMALL AREA OF NORTHEAST LOWER CENTERED
AROUND ALPENA (SUBSTANTIALLY DRIER DOWNSTATE).  30 DAY STANDARDIZED
PRECIP INDEX MOSTLY NEAR NORMAL.  SOIL MOISTURE ABOVE AVERAGE ACROSS
THE FORECAST AREA...MEAN STREAMFLOWS RUNNING NEAR TO ABOVE NORMAL ON
AREA RIVERS.

LARGE SCALE PATTERN/FORECAST: PROGRESSIVE 5 WAVE HEMISPHERIC PATTERN
WITH LONG WAVE TROUGHS OVER EASTERN CANADA/NEW ENGLAND AND THE
NORTHEAST PACIFIC.  PACIFIC HEIGHT FALLS MOVING ONTO THE WEST COAST
WITH A GRADUAL AMPLIFYING OF THE PATTERN IN RESPONSE...WITH RIDGING
BUILDING ACROSS THE NORTHERN PLAINS/CANADIAN PRAIRIES WITH A REMNANT
CLOSED LOW STUCK BENEATH THE RIDGE MOVING INTO THE TENNESSEE
VALLEY.  GOING FORWARD...SPLIT IN THE FLOW PATTERN EXPECTED TO
DEVELOP OUT WEST AS WESTERN TROUGH CROSSES THE ROCKY MOUNTAINS AND
INTO THE NATION`S MIDSECTION EARLY NEXT WEEK WHILE UPPER HIGH
DEVELOPS OVER THE CANADIAN PRAIRIES IN A BIT OF A SMALL SCALE
BLOCKING PATTERN.  QUASI-EAST/WEST ORIENTED FRONTAL BOUNDARY RUNNING
FROM THE NORTHERN PLAINS ACROSS THE MID MISSISSIPPI VALLEY/OHIO
VALLEY THIS AFTERNOON WILL BE A FOCUS FOR PRECIPITATION DEVELOPMENT
OVER THE COMING DAYS...WITH THE WESTERN PORTION OF THE FRONT GETTING
PUSHED NORTHWARD IN RESPONSE TO FALLING PRESSURES TO THE LEE OF THE
ROCKIES.  EVENTUALLY...THIS FRONT MERGES WITH A COLD FRONT WITHIN
THE NORTHERN BRANCH FOLDING IN FROM THE NORTH ON MONDAY AS UPPER
LEVEL ENERGY PUSHES INTO THE MIDWEST. SO TRYING TO DISCERN RAIN
CHANCES OVER THE COMING DAYS AS THESE FEATURES COME TOGETHER WILL BE
THE MAIN WEATHER CONCERN INTO EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH MONDAY: SHORT WAVE RIDGING WILL BUILD INTO
THE UPPER LAKES SATURDAY NIGHT...WITH PERSISTENT LOW/MID LEVEL WARM
ADVECTION AS NORTHERN MICHIGAN SHOULD STILL BE ON THE COOL SIDE OF
THE OHIO VALLEY BAROCLINIC ZONE.  SHOULD STILL BE SOME CLOUDS AROUND
SATURDAY NIGHT WITHIN WARM ADVECTION/ISENTROPIC ASCENT...PROBABLY
CAN`T RULE OUT SOME SPOTTY LIGHT RAIN SHOWERS ESPECIALLY THE FARTHER
NORTH ONE GOES.  BUT THE GENERAL TREND OF IMPROVING CONDITIONS INTO
SUNDAY STILL LOOKS REASONABLE.  LOOKS LIKE BOUNDARY TO THE SOUTH
WILL TEND TO WEAKEN/MIX OUT SUNDAY...WITH AN INCREASE OF LOW LEVEL
MOISTURE INTO LOWER MICHIGAN WITH SOUTHERLY WINDS.  PROBABLY A
LITTLE TOO MOIST IN SOME OF THE GUIDANCE (E.G., NAM-WRF)...THUS WILL
KEEP THE FORECAST DRY AS IS CURRENTLY AND NOT INTRODUCE DIURNALLY
DRIVEN CONVECTIVE SHOWERS INTO THE FORECAST FOR SUNDAY AFTERNOON.
EXPECT SUNDAY AFTERNOON TO BE WARM WITH HIGHS WELL INTO THE 70S/
AROUND 80.

DEVELOPING/STRENGTHENING BAROCLINIC ZONE TO THE NORTH OF MICHIGAN
FORECAST TO BECOME BETTER ORGANIZED SUNDAY NIGHT INTO MONDAY AS IT
PRESSES SOUTH INTO THE UPPER PENINSULA AND POSSIBLY NUDGING INTO
NORTHERN LOWER MICHIGAN (AIDED BY COOL LAKE BREEZE CIRCULATION??).
POTENTIALLY ANOTHER WARM AND MORE HUMID AFTERNOON MONDAY...FORECAST
SOUNDINGS HAVE A LITTLE MORE CAPPY LOOK TO THEM BUT WILL HANG ONTO A
CHANCE OF THUNDERSTORMS FOCUSED MAINLY ON THE DIURNAL CYCLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): UNSETTLED WEATHER
THROUGH MIDWEEK AS BOUNDARY CONTINUES TO SAG INTO THE LOWER
PENINSULA...WITH CHANCES FOR THUNDERSTORMS BOTH TUESDAY AND
WEDNESDAY.  IF THE FRONT CAN CLEAR THE AREA WEDNESDAY NIGHT SHOULD
BE ABLE TO DRY THINGS OUT HEADING INTO THURSDAY/FRIDAY...BUT NOT
CERTAIN ABOUT HOW QUICKLY UPPER WAVE WILL MOVE OUT AND SUSPECT THAT
IT WILL BE SLOWER THAN DEPICTED BY THE GFS.  SO WILL SPLIT THE
DIFFERENCE HERE...DRAGGING POPS INTO THURSDAY THEN GOING DRY FOR
FRIDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 718 PM EDT FRI MAY 17 2013

VFR.

AS HIGH PRESSURE MOVES OFF TO OUR EAST...SOUTHERLY LOW AND MID
LEVEL FLOW IS SLOWLY PUSHING MORE MOIST AIR INTO THE REGION. SOME
SPRINKLES/-SHRA CONTINUE IN THE TVC/MBL AREA...ALONG WITH LOTS OF
MID CLOUDS. THE CLOUD COVER AND CHANCE FOR PRECIP WILL LIFT
NORTHWARD DURING THE NIGHT...LEADING TO A MOSTLY CLOUDY DAY ON
SATURDAY. HOWEVER...CIGS SHOULD REMAIN COMFORTABLY VFR...AND VSBY
RESTRICTIONS ARE ALSO NOT EXPECTED.

WINDS WILL BE LIGHT/VARIABLE TONIGHT...AND LIGHT FROM THE EAST
SATURDAY.


&&

.MARINE...
ISSUED AT 405 PM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TONIGHT WITH NO
MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES SATURDAY
THROUGH SUNDAY AND A HANDFUL OF SMALL CRAFT ADVISORIES MAY BE
NEEDED AT THAT TIME.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KAB
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...JZ
MARINE...MSB

000
FXUS63 KDTX 180033
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
833 PM EDT FRI MAY 17 2013

.UPDATE...

A UPDATE TO THE GRIDS/ZONES WAS ISSUED TO INCREASE THE CHANCES OF
LIGHT RAIN ACROSS THE SAGINAW VALLEY AND THUMB REGION. MID
TROPOSPHERIC FRONTOGENESIS HAS BEEN RATHER PERSISTENT AND HAS
RESULTED IN SEVERAL OBS REPORTING LIGHT RAIN OR SPRINKLES. THE
FGEN SHOULD PERSIST THROUGH 06Z TONIGHT BEFORE WANING LATE AS
SHORT WAVE RIDGING OVERSPREADS LOWER MI CAUSING THE MID LEVEL
FRONTAL CIRCULATION TO WEAKEN.

&&

.AVIATION...ISSUED 702 PM EDT FRI MAY 17 2013

//DISCUSSION...

STRONG HIGH PRESSURE PARKED ACROSS ERN ONTARIO AND QUEBEC WILL
MAINTAIN A FEED OF LOW LEVEL DRY AIR INTO SE MI UNDER PERSISTENT
EAST-SOUTHEASTERLY WINDS. THIS WILL SUSTAIN CLEAR SKIES BELOW 8000
FT THROUGH SAT MORNING. GIVEN THIS DRY LOW LEVEL AIR...THE RADAR
RETURNS NOW BLANKETING CENTRAL MI ARE MOSTLY LIGHT RAIN OR SPRINKLES.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 329 PM EDT FRI MAY 17 2013

SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL MOISTURE IN PLACE OVER SOUTHEAST MICHIGAN CONTINUES
TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY THE LAKE
AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL COME TOWARD
MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

UPDATE.......SC
AVIATION.....SC
SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KMQT 172329
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
729 PM EDT FRI MAY 17 2013

.UPDATE...
ISSUED AT 728 PM EDT FRI MAY 17 2013

LATEST MODELS HAVE TRENDED DRIER FOR THE OVERNGT FCST FOR UPR MI...
SHOWING MORE IMPRESSIVE H85 MOISTENING ASSOCIATED WITH ADVANCING
WARM FNT FOCUSED W OF UPR MI. GIVEN ESE FLOW OUT OF STUBBORN HUDSON
BAY HI PRES/DRY AIRMASS SHOWN ON THE 12Z APX RAOB...TRIMMED POPS
ACCORDINGLY. ALSO REMOVED MENTION OF TS TNGT AS 18Z NAM SHOWS MUCAPE
THRU 12Z SAT NO HIER THAN 5-50 J/KG.
&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

TRICKY PRECIP FORECAST IN THE SHORT TERM. CURRENTLY...THE CWA SITS
BETWEEN AN UPPER RIDGE OVER MN INTO CENTRAL CANADA AND AN UPPER LOW
OVER ERN QUEBEC. AT THE SFC...A HIGH IS OVER THE NE CWA WITH
DEVELOPING LOW PRESSURE OVER THE WRN PLAIN STATES. DRY AIR
ASSOCIATED WITH THE SFC HIGH HAS HELPED KEEP PRECIP/CLOUDS MOSTLY
S/SW OF THE CWA THIS AFTERNOON...BUT A LARGE ARE OF PRECIP IS
LOCATED N OF A WARM FRONT IN AN AREA OF MOISTURE ADVECTION OVER
CENTRAL WI. THE WARM FROM EXTENDS FROM SRN MN /WHERE CONVECTION HAS
DEVELOPED/ TO NRN IL...WHERE PRECIP IS ALSO BEING SEEN.

THE SFC HIGH SHIFTS SLIGHTLY E OVERNIGHT AS A SFC LOW DEEPENS OVER
THE WRN PLAINS...ALLOWING SLY FLOW TO INCREASE OVER THE CWA...BUT
DRY AIR TO KEEP A GRIP ON THE NERN CWA. THE WARM FRONT WILL MOVE N
INTO THE SW CWA AROUND 03Z SAT...FINALLY MOVING TO THE NE CWA BY 00Z
SUN. MODELS ARE ALL OVER THE PLACE WITH QPF LIKELY DUE TO CONVECTIVE
FEEDBACK...AND MANY DO NOT EVEN INITIALIZE WELL WITH QPF. SO
POPS/QPF/WEATHER ARE PRETTY UNCERTAIN LATER THIS EVENING INTO
SAT...BUT THERE ARE SOME THINGS WITH THE PRECIP THAT DO APPEAR MORE
CERTAIN. THE BEST MOISTURE ADVECTION/INSTABILITY WILL BE OVER THE
FAR WRN CWA CLOSER TO THE SFC LOW AND STRONGER SLY FLOW/LOW LEVEL
JET. KEPT HIGHEST POPS OVER THE W...WITH CHANCE POPS OVER THE
CENTRAL AND E CWA...AND ONLY SLIGHT CHANCE POPS OVER THE ERN CWA.
ANOTHER COMPLICATING FACTOR FOR PRECIP TONIGHT IS THE QUESTION ABOUT
CONVECTION DEVELOPING TO OUR S AND CUTTING OFF MOISTURE FLOW. THIS
MAY ACT TO FURTHER REDUCE PRECIP CHANCES...ESPECIALLY OVER THE
CENTRAL AND ERN CWA. EVEN WITH INCREASING LOW LEVEL TEMPS TONIGHT
INTO SAT...HIGHS ON SAT SHOULD NOT BE ALL THAT MUCH HIGHER THAN
TODAY IN MOST LOCATIONS DUE TO INCREASED CLOUD COVER SAT.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

SAT NIGHT AND SUNDAY...MODELS SUGGEST THAT MID/UPPER LEVEL RIDGING
WILL PREVAIL DOWNSTREAM FROM THE TROUGH DIGGING INTO THE PLAINS.
EXPECT THAT THE AREA WILL REMAIN MAINLY DRY AS THE MOISTURE AXIS
REMAINS WEST OF THE CWA AND THE THE FOCUS FOR STRONGER ISENTROPIC
LIFT WITH THE 850-700 MB FRONT REMAINS WELL TO THE NORTH. POPS
CLIMB SLIGHTLY SUNDAY AFTERNOON OVER THE WEST AS THE TROUGH SHIFTS
TO THE EAST AND THE POTENTIAL FOR WEAK SHRTWVS LIFTING TOWARD THE
REGION INCREASES. MUCAPE VALUES TO NEAR 1K J/KG WILL ALSO SUPPORT
POTENTIAL FOR TSRA.

SUN NIGHT INTO MON...THE ECMWF/GFS/GEM WERE IN GOOD AGREEMENT WITH
THE POSITION OF THE DEVELOPING CLOSE MID LEVEL LOW AND SFC LOW FROM
ERN NEBRASKA TO THE SW CORNER OF MN. THIS WILL ALLOW ENOUGH GULF
MOISTURE INFLOW TO PUSH PWAT VALUES TO NEAR 1.5 INCHES (NEAR 200 PCT
OF NORMAL). THE ABUNDANT MOISTURE ALONG WITH INCREASING FORCING FOR
ASCENT WITH UPPER LEVEL DIV AND 700-300 MB QVECTOR CONV AHEAD OF THE
LOW WILL SUPPORT LIKELY POPS SPREADING INTO THE CWA SUNDAY NIGHT AND
LINGERING THROUGH MONDAY. SCT TSRA ARE ALSO EXPECTED WITH THE
MAINLY ELEVATED CONVECTION NORTH OF THE SFC WARM FRONT MOVING TOWARD
NRN WI.

TUE-FRI...UNCERTAINTY INCREASES AS MODEL SHOW LARGER DIFFERENCES IN
HANDLING THE THE SLOW MOVING MID LEVEL LOW/TROUGH. THE 12Z ECMWF AND GEM
SUGGEST THAT THE LOW WILL ONLY SLOWLY WEAKEN AND SLIDE TO THE
EAST...KEEPING PCPN CHANCES IN THE AREA THROUGH THU WHILE THE 12Z
GFS AND 00Z ECMWF PUSH THE TROUGH AND FRONT TO THE SOUTH AS
STRENGTHENING NRN STREAM FLOW DEVELOPS FROM NRN ONTARIO INTO THE NRN
LAKES.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 728 PM EDT FRI MAY 17 2013

EXPECT VFR CONDITIONS/DRY WX TO PERSIST THRU THIS EVNG. BUT AS A
WARM FNT MOVES IN FM THE S...SOME -SHRA/MVFR CIGS WL BE PSBL...
MAINLY AT CMX/IWD WHERE LLVL WARM/MOIST ADVCTN WL BE MOST
PRONOUNCED. FOLLOWING THE WARM FROPA SAT MRNG...EXPECT WSHFT TO THE
S AND A RETURN TO PREDOMINANT VFR WX WITH DAYTIME HEATING/MIXING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...KC
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...KC
MARINE...TITUS

000
FXUS63 KAPX 172318
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
718 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 405 PM EDT FRI MAY 17 2013

AS HIGH PRESSURE EXITS TOWARD THE NORTH ATLANTIC...NORTHERN
MICHIGAN`S WEATHER WILL GROW INCREASINGLY UNSETTLED INTO THE
WEEKEND...WITH SCATTERED SHOWERS POSSIBLE MAINLY ON SATURDAY. A
STORM SYSTEM CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO
THE PLAINS ON SATURDAY AND INTO THE GREAT LAKES TO START THE WORK
WEEK. THIS WILL GENERATE SHOWERS AND THUNDERSTORMS WHILE CONTINUING
EXTREMELY WARM TEMPERATURES OVER NORTHERN MICHIGAN INTO MIDWEEK.

&&

.UPDATE...
ISSUED AT 718 PM EDT FRI MAY 17 2013

PRECIP IS LINGERING BUT GETTING LIGHTER IN SOUTH OF M-72. SOME
TWEAKS MADE TO THE MID-EVENING POPS...TO BOOST IN THE FAR SOUTH
AND TO ERODE ALONG THE NORTHERN EDGE. CLOUD COVER HAS BEEN
DECREASING ALONG THE M-32 CORRIDOR...AND HAVE DECREASED EVENING
CLOUD COVER FROM THERE NORTH. WITH WARM/MOIST ADVECTION EXPANDING
NE WITH TIME TONIGHT...THIS CLEARING WILL BE TEMPORARY.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RATHER INTERESTING FORECAST UNFOLDING THIS AFTERNOON...WITH REMNANTS
OF UPSTREAM EARLY MORNING MCS SPREADING ALONG THE M-55 CORRIDOR...
IN-SPITE OF PERSISTENT LOW LEVEL DRYING. WIDESPREAD LIGHT RAINS THE
RESULT SOUTH OF GRAND TRAVERSE BAY...WITH DEEP LAYER DRY WEDGE AND
LACK OF FORCING MAINTAINING DRY WEATHER ELSEWHERE. TEMPERATURES HAVE
RESPONDED ACCORDINGLY...WITH THE "WARMEST" READINGS WELL INTO THE
60S ACROSS THE NORTH...WITH THOSE EXPERIENCING RAIN STUCK MAINLY IN
THE 50S. FORECAST CONCERNS THROUGH SATURDAY CENTER ON ADDITIONAL
RAIN CHANCES AS WELL AS CLOUD AND TEMPERATURE TRENDS.

OVERNIGHT CONFIDENCE HAS TAKEN A REMARKABLE DOWNWARD TREND AFTER
TODAY`S EVENTS. BEST GUESS SUGGESTS ONGOING ACTIVITY WILL WANE
THROUGH THE AFTERNOON...WITH INCREASING FOCUS FOR RENEWED ACTIVITY
FURTHER TO OUR NORTHWEST WHERE MOISTURE/MASS CONVERGENCE IS
MAXIMIZED ON NOSE OF LOW LEVEL JET AND ALONG ELEVATED WARM FRONT.
DESPITE SOME LOW LEVEL MOISTENING...FEEL BEST BET FOR ANY RAINS
REACHING THE SURFACE WILL REMAIN ACROSS WISCONSIN INTO WESTERN UPPER
MICHIGAN THROUGH THE OVERNIGHT. NORTHEAST BOWING THETA-E RIDGE MAY
SUPPORT SOME LIGHT SHOWERS ADVANCING EAST FROM GENERATION
REGION...PERHAPS BRINGING SOME SCATTERED LIGHT SHOWERS TO PARTS OF
THE AREA (ESPECIALLY THE WESTERN HALF WHERE LOW LEVEL MOISTURE WILL
BE DEEPER). WILL CONTINUE TO WORD AS SUCH...KEEPING JUST LOW END
MENTION FOR LIGHT SHOWERS SLOWLY ADVANCING NORTH WITH TIME. PLENTY
OF CLOUDS TONIGHT SUPPORTS MUCH WARMER TEMPERATURES THAN THOSE
OBSERVED LAST NIGHT...WITH WIDESPREAD READINGS IN THE 40S.

PERHAPS SOME LINGERING LIGHT SHOWERS SATURDAY MORNING...OTHERWISE A
MAINLY DRY DAY IS EXPECTED AS MID LEVEL RIDGING BUILDS OVERHEAD AND
FOCUS FOR ADDITIONAL SHOWERS SHUNTS EVEN FURTHER NORTHWEST. CLOUDS
SHOULD DOMINATE EARLY...WITH TRENDS SUPPORTING SOME AFTERNOON
CLEARING SPREADING IN FROM THE SOUTHWEST. TEMPERATURES HIGHLY
DEPENDENT ON JUST HOW AGGRESSIVE CLEARING BECOMES. A BLEND BETWEEN
COOL GUIDANCE AND INHERITED WARM READINGS SEEMS AS GOOD A STARTING
POINT AS ANY...GIVING HIGHS IN THE UPPER 60S AND LOWER 70S.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RECENT TRENDS: TEMPERATURES...STARTING TO RECOVER FROM RECENT COOL
SPELL...3-4C BELOW NORMAL LAST 7 DAYS AND NEAR TO A LITTLE (1-2C)
ABOVE NORMAL FOR THE MONTH OF MAY (WESTERN AND LOWER GREAT LAKES/NEW
ENGLAND WARMTH...COOL IN BETWEEN AND ACROSS THE SOUTHEAST AND GULF
COAST.  PRECIPITATION/HYDROLOGY...BEEN DRIER PAST COUPLE OF DAYS...
PRECIP LAST 7 DAYS 150-300 PERCENT NORMAL EAST OF I-75...MUCH DRIER
ACROSS EASTERN UPPER AND WEST OF US-131 CORRIDOR.  MONTH-TO-DATE
BELOW NORMAL PRECIP EXCEPT SMALL AREA OF NORTHEAST LOWER CENTERED
AROUND ALPENA (SUBSTANTIALLY DRIER DOWNSTATE).  30 DAY STANDARDIZED
PRECIP INDEX MOSTLY NEAR NORMAL.  SOIL MOISTURE ABOVE AVERAGE ACROSS
THE FORECAST AREA...MEAN STREAMFLOWS RUNNING NEAR TO ABOVE NORMAL ON
AREA RIVERS.

LARGE SCALE PATTERN/FORECAST: PROGRESSIVE 5 WAVE HEMISPHERIC PATTERN
WITH LONG WAVE TROUGHS OVER EASTERN CANADA/NEW ENGLAND AND THE
NORTHEAST PACIFIC.  PACIFIC HEIGHT FALLS MOVING ONTO THE WEST COAST
WITH A GRADUAL AMPLIFYING OF THE PATTERN IN RESPONSE...WITH RIDGING
BUILDING ACROSS THE NORTHERN PLAINS/CANADIAN PRAIRIES WITH A REMNANT
CLOSED LOW STUCK BENEATH THE RIDGE MOVING INTO THE TENNESSEE
VALLEY.  GOING FORWARD...SPLIT IN THE FLOW PATTERN EXPECTED TO
DEVELOP OUT WEST AS WESTERN TROUGH CROSSES THE ROCKY MOUNTAINS AND
INTO THE NATION`S MIDSECTION EARLY NEXT WEEK WHILE UPPER HIGH
DEVELOPS OVER THE CANADIAN PRAIRIES IN A BIT OF A SMALL SCALE
BLOCKING PATTERN.  QUASI-EAST/WEST ORIENTED FRONTAL BOUNDARY RUNNING
FROM THE NORTHERN PLAINS ACROSS THE MID MISSISSIPPI VALLEY/OHIO
VALLEY THIS AFTERNOON WILL BE A FOCUS FOR PRECIPITATION DEVELOPMENT
OVER THE COMING DAYS...WITH THE WESTERN PORTION OF THE FRONT GETTING
PUSHED NORTHWARD IN RESPONSE TO FALLING PRESSURES TO THE LEE OF THE
ROCKIES.  EVENTUALLY...THIS FRONT MERGES WITH A COLD FRONT WITHIN
THE NORTHERN BRANCH FOLDING IN FROM THE NORTH ON MONDAY AS UPPER
LEVEL ENERGY PUSHES INTO THE MIDWEST. SO TRYING TO DISCERN RAIN
CHANCES OVER THE COMING DAYS AS THESE FEATURES COME TOGETHER WILL BE
THE MAIN WEATHER CONCERN INTO EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH MONDAY: SHORT WAVE RIDGING WILL BUILD INTO
THE UPPER LAKES SATURDAY NIGHT...WITH PERSISTENT LOW/MID LEVEL WARM
ADVECTION AS NORTHERN MICHIGAN SHOULD STILL BE ON THE COOL SIDE OF
THE OHIO VALLEY BAROCLINIC ZONE.  SHOULD STILL BE SOME CLOUDS AROUND
SATURDAY NIGHT WITHIN WARM ADVECTION/ISENTROPIC ASCENT...PROBABLY
CAN`T RULE OUT SOME SPOTTY LIGHT RAIN SHOWERS ESPECIALLY THE FARTHER
NORTH ONE GOES.  BUT THE GENERAL TREND OF IMPROVING CONDITIONS INTO
SUNDAY STILL LOOKS REASONABLE.  LOOKS LIKE BOUNDARY TO THE SOUTH
WILL TEND TO WEAKEN/MIX OUT SUNDAY...WITH AN INCREASE OF LOW LEVEL
MOISTURE INTO LOWER MICHIGAN WITH SOUTHERLY WINDS.  PROBABLY A
LITTLE TOO MOIST IN SOME OF THE GUIDANCE (E.G., NAM-WRF)...THUS WILL
KEEP THE FORECAST DRY AS IS CURRENTLY AND NOT INTRODUCE DIURNALLY
DRIVEN CONVECTIVE SHOWERS INTO THE FORECAST FOR SUNDAY AFTERNOON.
EXPECT SUNDAY AFTERNOON TO BE WARM WITH HIGHS WELL INTO THE 70S/
AROUND 80.

DEVELOPING/STRENGTHENING BAROCLINIC ZONE TO THE NORTH OF MICHIGAN
FORECAST TO BECOME BETTER ORGANIZED SUNDAY NIGHT INTO MONDAY AS IT
PRESSES SOUTH INTO THE UPPER PENINSULA AND POSSIBLY NUDGING INTO
NORTHERN LOWER MICHIGAN (AIDED BY COOL LAKE BREEZE CIRCULATION??).
POTENTIALLY ANOTHER WARM AND MORE HUMID AFTERNOON MONDAY...FORECAST
SOUNDINGS HAVE A LITTLE MORE CAPPY LOOK TO THEM BUT WILL HANG ONTO A
CHANCE OF THUNDERSTORMS FOCUSED MAINLY ON THE DIURNAL CYCLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): UNSETTLED WEATHER
THROUGH MIDWEEK AS BOUNDARY CONTINUES TO SAG INTO THE LOWER
PENINSULA...WITH CHANCES FOR THUNDERSTORMS BOTH TUESDAY AND
WEDNESDAY.  IF THE FRONT CAN CLEAR THE AREA WEDNESDAY NIGHT SHOULD
BE ABLE TO DRY THINGS OUT HEADING INTO THURSDAY/FRIDAY...BUT NOT
CERTAIN ABOUT HOW QUICKLY UPPER WAVE WILL MOVE OUT AND SUSPECT THAT
IT WILL BE SLOWER THAN DEPICTED BY THE GFS.  SO WILL SPLIT THE
DIFFERENCE HERE...DRAGGING POPS INTO THURSDAY THEN GOING DRY FOR
FRIDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 718 PM EDT FRI MAY 17 2013

VFR.

AS HIGH PRESSURE MOVES OFF TO OUR EAST...SOUTHERLY LOW AND MID
LEVEL FLOW IS SLOWLY PUSHING MORE MOIST AIR INTO THE REGION. SOME
SPRINKLES/-SHRA CONTINUE IN THE TVC/MBL AREA...ALONG WITH LOTS OF
MID CLOUDS. THE CLOUD COVER AND CHANCE FOR PRECIP WILL LIFT
NORTHWARD DURING THE NIGHT...LEADING TO A MOSTLY CLOUDY DAY ON
SATURDAY. HOWEVER...CIGS SHOULD REMAIN COMFORTABLY VFR...AND VSBY
RESTRICTIONS ARE ALSO NOT EXPECTED.

WINDS WILL BE LIGHT/VARIABLE TONIGHT...AND LIGHT FROM THE EAST
SATURDAY.

&&

.MARINE...
ISSUED AT 405 PM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TONIGHT WITH NO
MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES SATURDAY
THROUGH SUNDAY AND A HANDFUL OF SMALL CRAFT ADVISORIES MAY BE
NEEDED AT THAT TIME.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...JZ
SYNOPSIS...KAB
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...JZ
MARINE...MSB

000
FXUS63 KDTX 172302
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
702 PM EDT FRI MAY 17 2013


.AVIATION...

//DISCUSSION...

STRONG HIGH PRESSURE PARKED ACROSS ERN ONTARIO AND QUEBEC WILL
MAINTAIN A FEED OF LOW LEVEL DRY AIR INTO SE MI UNDER PERSISTENT
EAST-SOUTHEASTERLY WINDS. THIS WILL SUSTAIN CLEAR SKIES BELOW 8000
FT THROUGH SAT MORNING. GIVEN THIS DRY LOW LEVEL AIR...THE RADAR
RETURNS NOW BLANKETING CENTRAL MI ARE MOSTLY LIGHT RAIN OR SPRINKLES.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 329 PM EDT FRI MAY 17 2013

SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL MOISTURE IN PLACE OVER SOUTHEAST MICHIGAN CONTINUES
TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY THE LAKE
AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL COME TOWARD
MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....SC
SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 172300
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
700 PM EDT FRI MAY 17 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 253 PM EDT FRI MAY 17 2013

A LOW PRESSURE SYSTEM DEVELOPING IN COLORADO WILL TRACK SLOWLY
TOWARD MICHIGAN THROUGH EARLY NEXT WEEK. SOUTHEAST WINDS OUT AHEAD
OF THIS SYSTEM WILL LEAD TO A WARMING TREND. ALSO MOISTURE WILL BE
ON THE INCREASE OVER TIME AND THE WEATHER WILL TURN UNSETTLED FOR
EARLY NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 253 PM EDT FRI MAY 17 2013

THE MAIN CHALLENGE DEALS WITH THE CHANCES FOR SHOWERS TONIGHT.

THE PERSISTENT AREA OF SHOWERS CONTINUES TO IMPACT THE REGION
MAINLY NORTH OF A MUSKEGON TO ALMA LINE. OTHER SHOWERS WERE
DEVELOPING OVER LAKE MI AND WERE TRACKING NORTHEAST. THE PV
ANOMALY RESPONSIBLE FOR THE SHOWERS WAS WEAKENING. IR IMAGERY
SHOWS THE CLOUD TOPS WARMING AND RADAR TRENDS SHOW THE
PRECIPITATION WEAKENING. WILL FEATURE AN EVENING PERIOD IN THE
FORECAST TO COVER THE SHOWERS ONGOING AND THEN FEATURE A LOWER POP
FOR TONIGHT.

I CONSIDERED ADDING AN AFTERNOON THUNDERSTORM TO THE FORECAST FOR
SATURDAY FOR LOCATIONS SOUTHWEST OF GRAND RAPIDS. WEAK FORCING BUT
SOME INSTABILITY IS EXPECTED. LIFTED INDEX VALUES DROP DOWN TO -2
TO -4 DEG C. THE INSTABILITY IS NOT PROGGED TO BE AS STRONG AS
TODAYS VALUES DOWN IN INDIANA WHERE THUNDERSTORMS WERE DEVELOPING.
SO WILL KEEP IT DRY FOR NOW.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 253 PM EDT FRI MAY 17 2013

FORECAST CONCERNS DURING THE LONG TERM DEAL WITH THUNDERSTORM
POTENTIAL. MEDIUM RANGE MODELS ARE LOOKING INCREASINGLY WET DURING
THE FIRST HALF OF NEXT WEEK. A SLOW MOVING NORTHERN PLAINS LOW WILL
DRIFT EAST NEXT WEEK. A STATIONARY FRONT IS PROGD TO EXTEND EWD FROM
THE LOW THROUGH NRN WISCONSIN INTO NRN LWR. WE/LL BE IN THE WARM
SECTOR SOUTH OF THE ACTIVE FRONTAL BOUNDARY. SHORT WAVES EJECTING
FROM THE ASSOCIATED UPPER LOW WILL RESULT IN SCT TO NUMEROUS
THUNDERSTORMS MON-WED. PLENTY OF INSTABILITY WILL EXIST WITH LI/S
NEAR -8C AND SBCAPE IN THE 2K-3K J/KG RANGE. SHEAR VALUES AROUND 40
KTS SUGGESTS STRONG STORMS POSSIBLE BUT NOT TOTALLY SOLD ON THE SVR
POTENTIAL YET. MOISTURE SHOULDN/T BE A LIMITING FACTOR AS A 30KT SW
FLOW WILL DRAW MOISTURE NWD FROM THE GULF. CONVECTIVE INITIATION
WILL LIKELY DEPEND ON MULTITUDE OF SHORT WAVES MOVING ACROSS THE
GREAT LAKES.

THE CONVECTIVE THREAT WILL DIMINISH AFTER WEDNESDAY AS THE SFC LOW
MOVES EAST OF THE CWA AND COOLER AND MORE STABLE NE WINDS DEVELOP.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 702 PM EDT FRI MAY 17 2013

EXPECT VFR CIGS/VSBY THROUGH SATURDAY AFTERNOON AT ALL TAF SITES.

LAYERED CLOUDS (VFR CIGS) WILL PERSIST THROUGH SATURDAY
AFTERNOON. THE CLOUDS ARE THE RESULT OF MID LEVEL MOISTURE BEING
LIFTED NORTHWARD OVER A WEAK STATION FRONT SOUTH OF INTERSTATE 80.
A WEAKENING SOUTHERN STREAM SYSTEM PASSING THROUGH THE LOWER OHIO
VALLEY (SHOWERS WITH THAT SHOULD STAY SOUTH OF INTERSTATE 80) WILL
CONTINUE TO FEED MOISTURE NORTHWARD OVER THAT STATIONARY FRONT
UNTIL IT IS EAST OF OHIO/KENTUCKY LATE IN THE DAY ON SATURDAY. LIFT
FROM THE ENTRANCE REGION OF POLAR JET OVER NORTHEAST OF LAKE
HURON IS ALSO AIDING THE DEVELOPMENT OF A EXTENSIVE AREA OF
LAYERED CLOUDS (RAIN NORTH OF ROUTE 10) OVER MICHIGAN/WISCONSIN.
BY LATE IN THE DAY SATURDAY THE SOUTHERN STREAM SYSTEM SHOULD BE
FAR ENOUGH EAST TO CUT OFF THE FEED OF MOISTURE OVER THE FRONT TO
OUR SOUTH WHILE AT THE SAME TIME THE JET ENTRANCE REGION OF THE
POLAR JET SHOULD ALSO BE FAR ENOUGH EAST SO AS TO REDUCE THE LIFT
AT MID LEVELS OVER LOWER MICHIGAN. THAT COMBINATION OF THOSE TWO
FEATURES SHOULD RESULT IN CLEARING SKIES TOWARD SATURDAY EVENING.

&&

.MARINE...
ISSUED AT 253 PM EDT FRI MAY 17 2013

GENERAL OFFSHORE FLOW WILL KEEP WAVE HEIGHTS TO A MINIMUM.
PRESSURE GRADIENT REMAINS RELATIVELY WEAK...SO WIND TO STAY UNDER SCA.


&&

.FIRE WEATHER...
ISSUED AT 253 PM EDT FRI MAY 17 2013

HUMIDITY LEVELS SHOULD DROP OFF INTO THE 25 TO 30 PERCENT RANGE
SOUTH OF GRAND RAPIDS THROUGH ABOUT 23Z. THIS COMBINED WITH TEMPS
IN THE 70S WILL LEAD TO AN ELEVATED FIRE DANGER RISK.

&&

.HYDROLOGY...
ISSUED AT 253 PM EDT FRI MAY 17 2013

LOCALIZED SHOWERS NOT CREATING MUCH QPF THIS
AFTERNOON...GENERALLY UNDER A TENTH OF AN INCH. A HIGHER RISK FOR
HEAVIER SHOWERS WILL ARRIVE BY MONDAY AS GULF MOISTURE WORKS ITS
WAY INTO THE AREA.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...WDM
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KMQT 172049
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
449 PM EDT FRI MAY 17 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

TRICKY PRECIP FORECAST IN THE SHORT TERM. CURRENTLY...THE CWA SITS
BETWEEN AN UPPER RIDGE OVER MN INTO CENTRAL CANADA AND AN UPPER LOW
OVER ERN QUEBEC. AT THE SFC...A HIGH IS OVER THE NE CWA WITH
DEVELOPING LOW PRESSURE OVER THE WRN PLAIN STATES. DRY AIR
ASSOCIATED WITH THE SFC HIGH HAS HELPED KEEP PRECIP/CLOUDS MOSTLY
S/SW OF THE CWA THIS AFTERNOON...BUT A LARGE ARE OF PRECIP IS
LOCATED N OF A WARM FRONT IN AN AREA OF MOISTURE ADVECTION OVER
CENTRAL WI. THE WARM FROM EXTENDS FROM SRN MN /WHERE CONVECTION HAS
DEVELOPED/ TO NRN IL...WHERE PRECIP IS ALSO BEING SEEN.

THE SFC HIGH SHIFTS SLIGHTLY E OVERNIGHT AS A SFC LOW DEEPENS OVER
THE WRN PLAINS...ALLOWING SLY FLOW TO INCREASE OVER THE CWA...BUT
DRY AIR TO KEEP A GRIP ON THE NERN CWA. THE WARM FRONT WILL MOVE N
INTO THE SW CWA AROUND 03Z SAT...FINALLY MOVING TO THE NE CWA BY 00Z
SUN. MODELS ARE ALL OVER THE PLACE WITH QPF LIKELY DUE TO CONVECTIVE
FEEDBACK...AND MANY DO NOT EVEN INITIALIZE WELL WITH QPF. SO
POPS/QPF/WEATHER ARE PRETTY UNCERTAIN LATER THIS EVENING INTO
SAT...BUT THERE ARE SOME THINGS WITH THE PRECIP THAT DO APPEAR MORE
CERTAIN. THE BEST MOISTURE ADVECTION/INSTABILITY WILL BE OVER THE
FAR WRN CWA CLOSER TO THE SFC LOW AND STRONGER SLY FLOW/LOW LEVEL
JET. KEPT HIGHEST POPS OVER THE W...WITH CHANCE POPS OVER THE
CENTRAL AND E CWA...AND ONLY SLIGHT CHANCE POPS OVER THE ERN CWA.
ANOTHER COMPLICATING FACTOR FOR PRECIP TONIGHT IS THE QUESTION ABOUT
CONVECTION DEVELOPING TO OUR S AND CUTTING OFF MOISTURE FLOW. THIS
MAY ACT TO FURTHER REDUCE PRECIP CHANCES...ESPECIALLY OVER THE
CENTRAL AND ERN CWA. EVEN WITH INCREASING LOW LEVEL TEMPS TONIGHT
INTO SAT...HIGHS ON SAT SHOULD NOT BE ALL THAT MUCH HIGHER THAN
TODAY IN MOST LOCATIONS DUE TO INCREASED CLOUD COVER SAT.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 447 PM EDT FRI MAY 17 2013

SAT NIGHT AND SUNDAY...MODELS SUGGEST THAT MID/UPPER LEVEL RIDGING
WILL PREVAIL DOWNSTREAM FROM THE TROUGH DIGGING INTO THE PLAINS.
EXPECT THAT THE AREA WILL REMAIN MAINLY DRY AS THE MOISTURE AXIS
REMAINS WEST OF THE CWA AND THE THE FOCUS FOR STRONGER ISENTROPIC
LIFT WITH THE 850-700 MB FRONT REMAINS WELL TO THE NORTH. POPS
CLIMB SLIGHTLY SUNDAY AFTERNOON OVER THE WEST AS THE TROUGH SHIFTS
TO THE EAST AND THE POTENTIAL FOR WEAK SHRTWVS LIFTING TOWARD THE
REGION INCREASES. MUCAPE VALUES TO NEAR 1K J/KG WILL ALSO SUPPORT
POTENTIAL FOR TSRA.

SUN NIGHT INTO MON...THE ECMWF/GFS/GEM WERE IN GOOD AGREEMENT WITH
THE POSITION OF THE DEVELOPING CLOSE MID LEVEL LOW AND SFC LOW FROM
ERN NEBRASKA TO THE SW CORNER OF MN. THIS WILL ALLOW ENOUGH GULF
MOISTURE INFLOW TO PUSH PWAT VALUES TO NEAR 1.5 INCHES (NEAR 200 PCT
OF NORMAL). THE ABUNDANT MOISTURE ALONG WITH INCREASING FORCING FOR
ASCENT WITH UPPER LEVEL DIV AND 700-300 MB QVECTOR CONV AHEAD OF THE
LOW WILL SUPPORT LIKELY POPS SPREADING INTO THE CWA SUNDAY NIGHT AND
LINGERING THROUGH MONDAY. SCT TSRA ARE ALSO EXPECTED WITH THE
MAINLY ELEVATED CONVECTION NORTH OF THE SFC WARM FRONT MOVING TOWARD
NRN WI.

TUE-FRI...UNCERTAINTY INCREASES AS MODEL SHOW LARGER DIFFERENCES IN
HANDLING THE THE SLOW MOVING MID LEVEL LOW/TROUGH. THE 12Z ECMWF AND GEM
SUGGEST THAT THE LOW WILL ONLY SLOWLY WEAKEN AND SLIDE TO THE
EAST...KEEPING PCPN CHANCES IN THE AREA THROUGH THU WHILE THE 12Z
GFS AND 00Z ECMWF PUSH THE TROUGH AND FRONT TO THE SOUTH AS
STRENGTHENING NRN STREAM FLOW DEVELOPS FROM NRN ONTARIO INTO THE NRN
LAKES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 140 PM EDT FRI MAY 17 2013

WITH A WARM FRONT MOVING INTO THE AREA TONIGHT...EXPECT INCREASING
CHANCES FOR RAIN SHOWERS AND POSSIBLY SOME THUNDER /TOO UNCERTAIN ON
THUNDER TO PUT IN TAF/ TO MOVE IN TONIGHT INTO SAT MORNING. EXPECT
PRIMARY LOWEST CIGS TO BE MVFR WITH LITTLE VIS RESTRICTIONS. CIGS
SHOULD IMPROVE SOME ON SAT DUE TO LOW LEVEL MIXING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...TITUS
MARINE...TITUS

000
FXUS63 KAPX 172005
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
405 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 405 PM EDT FRI MAY 17 2013

AS HIGH PRESSURE EXITS TOWARD THE NORTH ATLANTIC...NORTHERN
MICHIGAN`S WEATHER WILL GROW INCREASINGLY UNSETTLED INTO THE
WEEKEND...WITH SCATTERED SHOWERS POSSIBLE MAINLY ON SATURDAY. A
STORM SYSTEM CURRENTLY ORGANIZING OVER THE ROCKIES WILL MOVE INTO
THE PLAINS ON SATURDAY AND INTO THE GREAT LAKES TO START THE WORK
WEEK. THIS WILL GENERATE SHOWERS AND THUNDERSTORMS WHILE CONTINUING
EXTREMELY WARM TEMPERATURES OVER NORTHERN MICHIGAN INTO MIDWEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RATHER INTERESTING FORECAST UNFOLDING THIS AFTERNOON...WITH REMNANTS
OF UPSTREAM EARLY MORNING MCS SPREADING ALONG THE M-55 CORRIDOR...
IN-SPITE OF PERSISTENT LOW LEVEL DRYING. WIDESPREAD LIGHT RAINS THE
RESULT SOUTH OF GRAND TRAVERSE BAY...WITH DEEP LAYER DRY WEDGE AND
LACK OF FORCING MAINTAINING DRY WEATHER ELSEWHERE. TEMPERATURES HAVE
RESPONDED ACCORDINGLY...WITH THE "WARMEST" READINGS WELL INTO THE
60S ACROSS THE NORTH...WITH THOSE EXPERIENCING RAIN STUCK MAINLY IN
THE 50S. FORECAST CONCERNS THROUGH SATURDAY CENTER ON ADDITIONAL
RAIN CHANCES AS WELL AS CLOUD AND TEMPERATURE TRENDS.

OVERNIGHT CONFIDENCE HAS TAKEN A REMARKABLE DOWNWARD TREND AFTER
TODAY`S EVENTS. BEST GUESS SUGGESTS ONGOING ACTIVITY WILL WANE
THROUGH THE AFTERNOON...WITH INCREASING FOCUS FOR RENEWED ACTIVITY
FURTHER TO OUR NORTHWEST WHERE MOISTURE/MASS CONVERGENCE IS
MAXIMIZED ON NOSE OF LOW LEVEL JET AND ALONG ELEVATED WARM FRONT.
DESPITE SOME LOW LEVEL MOISTENING...FEEL BEST BET FOR ANY RAINS
REACHING THE SURFACE WILL REMAIN ACROSS WISCONSIN INTO WESTERN UPPER
MICHIGAN THROUGH THE OVERNIGHT. NORTHEAST BOWING THETA-E RIDGE MAY
SUPPORT SOME LIGHT SHOWERS ADVANCING EAST FROM GENERATION
REGION...PERHAPS BRINGING SOME SCATTERED LIGHT SHOWERS TO PARTS OF
THE AREA (ESPECIALLY THE WESTERN HALF WHERE LOW LEVEL MOISTURE WILL
BE DEEPER). WILL CONTINUE TO WORD AS SUCH...KEEPING JUST LOW END
MENTION FOR LIGHT SHOWERS SLOWLY ADVANCING NORTH WITH TIME. PLENTY
OF CLOUDS TONIGHT SUPPORTS MUCH WARMER TEMPERATURES THAN THOSE
OBSERVED LAST NIGHT...WITH WIDESPREAD READINGS IN THE 40S.

PERHAPS SOME LINGERING LIGHT SHOWERS SATURDAY MORNING...OTHERWISE A
MAINLY DRY DAY IS EXPECTED AS MID LEVEL RIDGING BUILDS OVERHEAD AND
FOCUS FOR ADDITIONAL SHOWERS SHUNTS EVEN FURTHER NORTHWEST. CLOUDS
SHOULD DOMINATE EARLY...WITH TRENDS SUPPORTING SOME AFTERNOON
CLEARING SPREADING IN FROM THE SOUTHWEST. TEMPERATURES HIGHLY
DEPENDENT ON JUST HOW AGGRESSIVE CLEARING BECOMES. A BLEND BETWEEN
COOL GUIDANCE AND INHERITED WARM READINGS SEEMS AS GOOD A STARTING
POINT AS ANY...GIVING HIGHS IN THE UPPER 60S AND LOWER 70S.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 405 PM EDT FRI MAY 17 2013

RECENT TRENDS: TEMPERATURES...STARTING TO RECOVER FROM RECENT COOL
SPELL...3-4C BELOW NORMAL LAST 7 DAYS AND NEAR TO A LITTLE (1-2C)
ABOVE NORMAL FOR THE MONTH OF MAY (WESTERN AND LOWER GREAT LAKES/NEW
ENGLAND WARMTH...COOL IN BETWEEN AND ACROSS THE SOUTHEAST AND GULF
COAST.  PRECIPITATION/HYDROLOGY...BEEN DRIER PAST COUPLE OF DAYS...
PRECIP LAST 7 DAYS 150-300 PERCENT NORMAL EAST OF I-75...MUCH DRIER
ACROSS EASTERN UPPER AND WEST OF US-131 CORRIDOR.  MONTH-TO-DATE
BELOW NORMAL PRECIP EXCEPT SMALL AREA OF NORTHEAST LOWER CENTERED
AROUND ALPENA (SUBSTANTIALLY DRIER DOWNSTATE).  30 DAY STANDARDIZED
PRECIP INDEX MOSTLY NEAR NORMAL.  SOIL MOISTURE ABOVE AVERAGE ACROSS
THE FORECAST AREA...MEAN STREAMFLOWS RUNNING NEAR TO ABOVE NORMAL ON
AREA RIVERS.

LARGE SCALE PATTERN/FORECAST: PROGRESSIVE 5 WAVE HEMISPHERIC PATTERN
WITH LONG WAVE TROUGHS OVER EASTERN CANADA/NEW ENGLAND AND THE
NORTHEAST PACIFIC.  PACIFIC HEIGHT FALLS MOVING ONTO THE WEST COAST
WITH A GRADUAL AMPLIFYING OF THE PATTERN IN RESPONSE...WITH RIDGING
BUILDING ACROSS THE NORTHERN PLAINS/CANADIAN PRAIRIES WITH A REMNANT
CLOSED LOW STUCK BENEATH THE RIDGE MOVING INTO THE TENNESSEE
VALLEY.  GOING FORWARD...SPLIT IN THE FLOW PATTERN EXPECTED TO
DEVELOP OUT WEST AS WESTERN TROUGH CROSSES THE ROCKY MOUNTAINS AND
INTO THE NATION`S MIDSECTION EARLY NEXT WEEK WHILE UPPER HIGH
DEVELOPS OVER THE CANADIAN PRAIRIES IN A BIT OF A SMALL SCALE
BLOCKING PATTERN.  QUASI-EAST/WEST ORIENTED FRONTAL BOUNDARY RUNNING
FROM THE NORTHERN PLAINS ACROSS THE MID MISSISSIPPI VALLEY/OHIO
VALLEY THIS AFTERNOON WILL BE A FOCUS FOR PRECIPITATION DEVELOPMENT
OVER THE COMING DAYS...WITH THE WESTERN PORTION OF THE FRONT GETTING
PUSHED NORTHWARD IN RESPONSE TO FALLING PRESSURES TO THE LEE OF THE
ROCKIES.  EVENTUALLY...THIS FRONT MERGES WITH A COLD FRONT WITHIN
THE NORTHERN BRANCH FOLDING IN FROM THE NORTH ON MONDAY AS UPPER
LEVEL ENERGY PUSHES INTO THE MIDWEST. SO TRYING TO DISCERN RAIN
CHANCES OVER THE COMING DAYS AS THESE FEATURES COME TOGETHER WILL BE
THE MAIN WEATHER CONCERN INTO EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH MONDAY: SHORT WAVE RIDGING WILL BUILD INTO
THE UPPER LAKES SATURDAY NIGHT...WITH PERSISTENT LOW/MID LEVEL WARM
ADVECTION AS NORTHERN MICHIGAN SHOULD STILL BE ON THE COOL SIDE OF
THE OHIO VALLEY BAROCLINIC ZONE.  SHOULD STILL BE SOME CLOUDS AROUND
SATURDAY NIGHT WITHIN WARM ADVECTION/ISENTROPIC ASCENT...PROBABLY
CAN`T RULE OUT SOME SPOTTY LIGHT RAIN SHOWERS ESPECIALLY THE FARTHER
NORTH ONE GOES.  BUT THE GENERAL TREND OF IMPROVING CONDITIONS INTO
SUNDAY STILL LOOKS REASONABLE.  LOOKS LIKE BOUNDARY TO THE SOUTH
WILL TEND TO WEAKEN/MIX OUT SUNDAY...WITH AN INCREASE OF LOW LEVEL
MOISTURE INTO LOWER MICHIGAN WITH SOUTHERLY WINDS.  PROBABLY A
LITTLE TOO MOIST IN SOME OF THE GUIDANCE (E.G., NAM-WRF)...THUS WILL
KEEP THE FORECAST DRY AS IS CURRENTLY AND NOT INTRODUCE DIURNALLY
DRIVEN CONVECTIVE SHOWERS INTO THE FORECAST FOR SUNDAY AFTERNOON.
EXPECT SUNDAY AFTERNOON TO BE WARM WITH HIGHS WELL INTO THE 70S/
AROUND 80.

DEVELOPING/STRENGTHENING BAROCLINIC ZONE TO THE NORTH OF MICHIGAN
FORECAST TO BECOME BETTER ORGANIZED SUNDAY NIGHT INTO MONDAY AS IT
PRESSES SOUTH INTO THE UPPER PENINSULA AND POSSIBLY NUDGING INTO
NORTHERN LOWER MICHIGAN (AIDED BY COOL LAKE BREEZE CIRCULATION??).
POTENTIALLY ANOTHER WARM AND MORE HUMID AFTERNOON MONDAY...FORECAST
SOUNDINGS HAVE A LITTLE MORE CAPPY LOOK TO THEM BUT WILL HANG ONTO A
CHANCE OF THUNDERSTORMS FOCUSED MAINLY ON THE DIURNAL CYCLE.

EXTENDED FORECAST (TUESDAY THROUGH FRIDAY): UNSETTLED WEATHER
THROUGH MIDWEEK AS BOUNDARY CONTINUES TO SAG INTO THE LOWER
PENINSULA...WITH CHANCES FOR THUNDERSTORMS BOTH TUESDAY AND
WEDNESDAY.  IF THE FRONT CAN CLEAR THE AREA WEDNESDAY NIGHT SHOULD
BE ABLE TO DRY THINGS OUT HEADING INTO THURSDAY/FRIDAY...BUT NOT
CERTAIN ABOUT HOW QUICKLY UPPER WAVE WILL MOVE OUT AND SUSPECT THAT
IT WILL BE SLOWER THAN DEPICTED BY THE GFS.  SO WILL SPLIT THE
DIFFERENCE HERE...DRAGGING POPS INTO THURSDAY THEN GOING DRY FOR
FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 116 PM EDT FRI MAY 17 2013

VFR CONDITIONS EXPECTED. EXTENSIVE DECK OF HIGH AND MID LEVEL
CLOUDS WILL CONTINUE TO AFFECT ALL TAF SITES RIGHT INTO SATURDAY
MORNING. LIGHT RAINS ALREADY OCCURRING AT KMBL...AND SHOULD
CONTINUE TO DO SO FOR THE NEXT FEW HOURS. RAINS MAY EDGE NORTH TO
TVC LATER THIS AFTERNOON...ALTHOUGH WITH NO IMPACT TO VIS. LIGHT
WINDS WILL REMAIN ACROSS THE AREA.

&&

.MARINE...
ISSUED AT 405 PM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TONIGHT WITH NO
MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES SATURDAY
THROUGH SUNDAY AND A HANDFUL OF SMALL CRAFT ADVISORIES MAY BE
NEEDED AT THAT TIME.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

SYNOPSIS...KAB
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...MSB
MARINE...MSB

000
FXUS63 KDTX 171945 CCA
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
329 PM EDT FRI MAY 17 2013

.SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL MOISTURE IN PLACE OVER SOUTHEAST MICHIGAN CONTINUES
TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY THE LAKE
AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL COME TOWARD
MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

&&

.LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

&&

.MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.AVIATION...ISSUED 1251 PM EDT FRI MAY 17 2013

//DISCUSSION...

HIGH PRESSURE TO THE NORTH AND AN ABUNDANCE OF LOW-LEVEL DRY AIR
WILL SUSTAIN LIGHT/STABLE EASTERLY FLOW AND VFR CONDITIONS THROUGH
THE TAF PERIOD. CONVECTIVE ACTIVITY OVER WISCONSIN IS NOT EXPECTED
TO SURVIVE ITS TREK EAST, ALTHOUGH PERIODS OF MID/HIGH CLOUDS ABOVE
5KFT CAN BE EXPECTED AS THE ASSOCIATED CLOUD COVER IS DRAWN
EASTWARD. FAR NORTH AND WEST LOCATIONS SUCH AS KMBS MAY SEE A BRIEF
PERIOD OF LIGHT RAINFALL OUT OF THIS ACTIVITY WITH NO RESTRICTION TO
VISIBILITY, WHILE REMAINING LOCATIONS WILL STAY DRY WITH PASSING MID
AND HIGH CLOUDS. IMPROVING MID-LEVEL MOISTURE QUALITY WILL BRING A
CHANCE FOR A CEILING BELOW 5KFT BY MORNING, BUT CONFIDENCE REMAINS
QUITE LOW AS STABILITY AND DRY AIR IN THE LOWEST 6KFT ARE EXPECTED
TO REMAIN LARGELY DOMINANT.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE IN CEILINGS BELOW 5KFT ON SATURDAY MORNING

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC
AVIATION.....JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KDTX 171929
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
329 PM EDT FRI MAY 17 2013

.SHORT TERM...TONIGHT

THE COMPACT AREA OF SHOWER AND OCCASIONAL THUNDERSTORM ACTIVITY OVER
CENTRAL/NORTHERN WISCONSIN WILL BE SUPPORTED THROUGH TONIGHT AS THE
JET OVER SOUTHERN ONTARIO STRENGTHENS IN RESPONSE TO LARGE SCALE
AMPLIFICATION. THE RESULTING NARROW CORRIDOR OF 300K FGEN AND MOIST
ISENTROPIC ASCENT THAT HAS BEEN SUPPORTING THESE SHOWERS WILL REMAIN
TIED TO THE SLOWLY EVOLVING LARGE SCALE PATTERN AND WILL THEREFORE
ESSENTIALLY REMAIN ANCHORED OVER NORTHERN WISCONSIN THROUGH THE
REMAINDER OF THE SHORT TERM PERIOD, ONLY SLOWLY LIFTING NORTHEAST
WITH TIME. SO FAR THIS AFTERNOON, NOTHING MORE THAN DRIZZLE HAS BEEN
OBSERVED ACROSS THE SAGINAW VALLEY. THIS IS EXPECTED GIVEN THAT THE
DEARTH OF LOW-LEVEL DRY AIR IN PLACE OVER SOUTHEAST MICHIGAN
CONTINUES TO BE SUPPORTED BY SYNOPTIC SCALE RIDGING AND ENHANCED BY
THE LAKE AGGREGATE. THE BEST CHANCE FOR MEASURABLE RAINFALL WILL
COME TOWARD MORNING IN THE SAGINAW VALLEY...PERHAPS EVEN THE WESTERN
THUMB...WHEN ADDITIONAL ENERGY SHEARS TOWARD LOWER MI AND ENHANCES
THE LOW-LEVEL FORCING FIELD. STILL FEEL THAT NOTHING BETTER THAN A
LOW CHC POP IS WARRANTED AT THIS TIME. INHERITED FORECAST LOWS IN
THE UPPER 40S REMAIN ROUGHLY ON TRACK AND NOT DISSIMILAR TO WHAT HAS
BEEN OBSERVED THE LAST FEW NIGHTS. HOWEVER, THE ABUNDANCE OF CLOUD
DEBRIS ADVECTING ACROSS THE PENINSULA THIS EVENING WARRANTS AN
UPWARD BOOST OF A COUPLE DEGREES.

&&

.LONG TERM...SATURDAY THROUGH NEXT FRIDAY

STABILIZING INFLUENCE OF UPPER RIDGING SHOULD HELP KEEP THE AREA DRY
THROUGH SUNDAY. MODELS SHOW A WEAK ELEVATED WARM FRONT (NEAR 925MB)
OVER SOUTHERN MICHIGAN TO START THE DAY LIFTING NORTHWARD INTO LAKE
HURON BY AFTERNOON. WITH NO UPPER SUPPORT...ONLY WEAK ISENTROPIC
ASCENT...AND VERY DRY AIR EXPECTED BELOW 6000 FEET...WILL CARRY A
DRY FORECAST. WOULD NOT BE SURPRISED TO SEE A FEW SPRINKLES
HOWEVER...BUT NOT MUCH WORTH MENTIONING AT THIS POINT. DO EXPECT
PLENTY OF MID AND HIGH LEVEL CLOUDS HOWEVER. SURFACE FRONT SHOULD
LIFT THROUGH LATE SATURDAY NIGHT INTO EARLY SUNDAY...BUT AGAIN
EXPECT DRY CONDITIONS. EXPECT A GRADUAL WARMING TREND OVER THE
WEEKEND AS WARMER AIR ARRIVES...WITH EASTERLY FLOW OFF THE COLD
WATERS OF THE GREAT LAKES KEEPING TEMPERATURES COOLER OVER THE EAST
SIDE OF THE STATE. SOUTHERLY FLOW ON SUNDAY WILL HELP BRING
TEMPERATURES NEAR TO ABOVE 80 BY AFTERNOON.

CHANCES FOR RAIN THEN START TO INCREASE LATE SUNDAY NIGHT INTO THE
FIRST HALF OF MONDAY AS THETA-E SURGE OCCURS AS A WEAK LOW LEVEL JET
NOSES UP INTO LOWER MICHIGAN. FORECAST COMPLEXITY THEN INCREASES
BEYOND THAT...WITH MODELS DIVERGING SIGNIFICANTLY WITH THE PATTERN
OVER THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES BY TUESDAY.
WILL BE WATCHING THE EVOLUTION...BOTH IN REAL LIFE AND IN THE
MODELS...OVER THE NEXT FEW DAYS AS THE LOW NEAR SOUTHERN CALIFORNIA
AND THE STRONG UPPER WAVE OFF BRITISH COLUMBIA INTERACT AND
EVENTUALLY MERGE OVER THE COUNTRY`S MID-SECTION. THIS SYSTEM IS THEN
FORECAST TO SLOWLY MOVE ACROSS THE GREAT LAKES/OHIO VALLEY THROUGH
MIDWEEK. FOR MONDAY...GFS AND EURO INDICATE EITHER A WARM FRONT OR
OCCLUSION MOVING ACROSS LOWER MICHIGAN DURING THE AFTERNOON AS
SURFACE LOW PRESSURE MOVES INTO SOUTHERN MINNESOTA. MODELS ALSO SHOW
A STRONG COLD FRONT POISED NORTH OF LAKE HURON. BOTH THESE FEATURES
WILL INCREASE SOUTHERLY FLOW OVER THE AREA...AND DEPENDENT ON CLOUD
COVER AND CONVECTIVE ACTIVITY...COULD LEAD TO A VERY WARM DAY ACROSS
SOUTHEAST MICHIGAN WITH TEMPERATURES WELL INTO THE 80S. WENT A
LITTLE CONSERVATIVE WITH TEMPS FOR NOW AS GOOD AMOUNT OF MOISTURE
AND INSTABILITY ALONG WITH A CONVECTIVE TRIGGER WILL MORE THAN
LIKELY PRODUCE ROUNDS OF CONVECTION AND CLOUDS ACROSS THE REGION.
ROUNDS OF SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO CONTINUE
THROUGH AT LEAST EARLY THURSDAY AS THE FRONT NORTH OF LAKE HURON
SINKS SOUTHWARD...AND POTENTIALLY STALLS OVER THE GREAT LAKES AS
RECENT MODEL RUNS HAVE SHOWN. UNCERTAINTY WITH TIMING GREATEST
THUNDERSTORM THREAT AND POPS OVERALL CENTERS AROUND DIFFERENT TRACKS
THE LOW MAY TAKE OVER THE GREAT LAKES/OHIO VALLEY...AND WHEN THE
STRONG COLD FRONT OVER CANADA WILL DROP DOWN THROUGH THE AREA.
CANNOT RULE OUT SEVERE WEATHER MONDAY THROUGH WEDNESDAY...BUT IT`S
REALLY TOO EARLY TO PIN DOWN THE DETAILS.

COOLER AND QUIET CONDITIONS WILL THEN RETURN FOR THE END OF THE WEEK
BEHIND THE SYSTEM...WITH MAX TEMPERATURES FALLING BELOW NORMAL FOR
THURSDAY AND FRIDAY.

&&

.MARINE...

GENTLE TO MODERATE EASTERLY BREEZE WILL VEER TO SOUTHERLY BY SUNDAY
NIGHT BEFORE INCREASING NEXT WEEK AS LOW PRESSURE LIFTS OUT OF THE
PLAINS. THIS LOW WILL BRING A CHANCE OF THUNDERSTORMS MONDAY THROUGH
AT LEAST WEDNESDAY AND WILL BE ACCOMPANIED BY A MODEST INCREASE IN
SOUTHERLY WINDS BY MONDAY AFTERNOON. A MID-WEEK WIND SHIFT TO
NORTHERLY CAN THEN BE EXPECTED AS A COLD FRONT PUSHES ACROSS AREA
WATERS. UNTIL THEN...SIGNIFICANT WAVE HEIGHTS WILL GENERALLY REMAIN
AT OR BELOW 2 FEET WITH THE EXCEPTION OF THE MICHIGAN WATERS OF LAKE
ERIE WHERE SIG WAVES OF UP TO 3 FEET WILL BE COMMON THROUGH SATURDAY
NIGHT.

&&

.AVIATION...ISSUED 1251 PM EDT FRI MAY 17 2013

//DISCUSSION...

HIGH PRESSURE TO THE NORTH AND AN ABUNDANCE OF LOW-LEVEL DRY AIR
WILL SUSTAIN LIGHT/STABLE EASTERLY FLOW AND VFR CONDITIONS THROUGH
THE TAF PERIOD. CONVECTIVE ACTIVITY OVER WISCONSIN IS NOT EXPECTED
TO SURVIVE ITS TREK EAST, ALTHOUGH PERIODS OF MID/HIGH CLOUDS ABOVE
5KFT CAN BE EXPECTED AS THE ASSOCIATED CLOUD COVER IS DRAWN
EASTWARD. FAR NORTH AND WEST LOCATIONS SUCH AS KMBS MAY SEE A BRIEF
PERIOD OF LIGHT RAINFALL OUT OF THIS ACTIVITY WITH NO RESTRICTION TO
VISIBILITY, WHILE REMAINING LOCATIONS WILL STAY DRY WITH PASSING MID
AND HIGH CLOUDS. IMPROVING MID-LEVEL MOISTURE QUALITY WILL BRING A
CHANCE FOR A CEILING BELOW 5KFT BY MORNING, BUT CONFIDENCE REMAINS
QUITE LOW AS STABILITY AND DRY AIR IN THE LOWEST 6KFT ARE EXPECTED
TO REMAIN LARGELY DOMINANT.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE IN CEILINGS BELOW 5KFT ON SATURDAY MORNING

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...JVC
LONG TERM....HLO
MARINE.......JVC
AVIATION.....JVC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 171914
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
314 PM EDT FRI MAY 17 2013

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/FIREWEATHER/HYDRO/MARINE

.SYNOPSIS...
ISSUED AT 253 PM EDT FRI MAY 17 2013

A LOW PRESSURE SYSTEM DEVELOPING IN COLORADO WILL TRACK SLOWLY
TOWARD MICHIGAN THROUGH EARLY NEXT WEEK. SOUTHEAST WINDS OUT AHEAD
OF THIS SYSTEM WILL LEAD TO A WARMING TREND. ALSO MOISTURE WILL BE
ON THE INCREASE OVER TIME AND THE WEATHER WILL TURN UNSETTLED FOR
EARLY NEXT WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 253 PM EDT FRI MAY 17 2013

THE MAIN CHALLENGE DEALS WITH THE CHANCES FOR SHOWERS TONIGHT.

THE PERSISTENT AREA OF SHOWERS CONTINUES TO IMPACT THE REGION
MAINLY NORTH OF A MUSKEGON TO ALMA LINE. OTHER SHOWERS WERE
DEVELOPING OVER LAKE MI AND WERE TRACKING NORTHEAST. THE PV
ANOMALY RESPONSIBLE FOR THE SHOWERS WAS WEAKENING. IR IMAGERY
SHOWS THE CLOUD TOPS WARMING AND RADAR TRENDS SHOW THE
PRECIPITATION WEAKENING. WILL FEATURE AN EVENING PERIOD IN THE
FORECAST TO COVER THE SHOWERS ONGOING AND THEN FEATURE A LOWER POP
FOR TONIGHT.

I CONSIDERED ADDING AN AFTERNOON THUNDERSTORM TO THE FORECAST FOR
SATURDAY FOR LOCATIONS SOUTHWEST OF GRAND RAPIDS. WEAK FORCING BUT
SOME INSTABILITY IS EXPECTED. LIFTED INDEX VALUES DROP DOWN TO -2
TO -4 DEG C. THE INSTABILITY IS NOT PROGGED TO BE AS STRONG AS
TODAYS VALUES DOWN IN INDIANA WHERE THUNDERSTORMS WERE DEVELOPING.
SO WILL KEEP IT DRY FOR NOW.



.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 253 PM EDT FRI MAY 17 2013

FORECAST CONCERNS DURING THE LONG TERM DEAL WITH THUNDERSTORM
POTENTIAL. MEDIUM RANGE MODELS ARE LOOKING INCREASINGLY WET DURING
THE FIRST HALF OF NEXT WEEK. A SLOW MOVING NORTHERN PLAINS LOW WILL
DRIFT EAST NEXT WEEK. A STATIONARY FRONT IS PROGD TO EXTEND EWD FROM
THE LOW THROUGH NRN WISCONSIN INTO NRN LWR. WE/LL BE IN THE WARM
SECTOR SOUTH OF THE ACTIVE FRONTAL BOUNDARY. SHORT WAVES EJECTING
FROM THE ASSOCIATED UPPER LOW WILL RESULT IN SCT TO NUMEROUS
THUNDERSTORMS MON-WED. PLENTY OF INSTABILITY WILL EXIST WITH LI/S
NEAR -8C AND SBCAPE IN THE 2K-3K J/KG RANGE. SHEAR VALUES AROUND 40
KTS SUGGESTS STRONG STORMS POSSIBLE BUT NOT TOTALLY SOLD ON THE SVR
POTENTIAL YET. MOISTURE SHOULDN/T BE A LIMITING FACTOR AS A 30KT SW
FLOW WILL DRAW MOISTURE NWD FROM THE GULF. CONVECTIVE INITIATION
WILL LIKELY DEPEND ON MULTITUDE OF SHORT WAVES MOVING ACROSS THE
GREAT LAKES.

THE CONVECTIVE THREAT WILL DIMINISH AFTER WEDNESDAY AS THE SFC LOW
MOVES EAST OF THE CWA AND COOLER AND MORE STABLE NE WINDS DEVELOP.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 104 PM EDT FRI MAY 17 2013

A STATIONARY FRONT OVER LOWER MICHIGAN WILL CONTINUE TO BE A FOCUS
FOR A MID CLOUD DECK THROUGH THE PERIOD. SHOWERS SEEN ON CURRENT
RADAR WILL MOSTLY STAY NORTH OF THE TAF SITES. HOWEVER A SPRINKLE
OR TWO CAN/T BE RULED OUT A KMKG BUT THE PROBABILITY WAS LOW
ENOUGH TO LEAVE OUT OF THE TAFS.


&&

.MARINE...
ISSUED AT 253 PM EDT FRI MAY 17 2013

GENERAL OFFSHORE FLOW WILL KEEP WAVE HEIGHTS TO A MINIMUM.
PRESSURE GRADIENT REMAINS RELATIVELY WEAK...SO WIND TO STAY UNDER SCA.



&&

.FIRE WEATHER...
ISSUED AT 253 PM EDT FRI MAY 17 2013

HUMIDITY LEVELS SHOULD DROP OFF INTO THE 25 TO 30 PERCENT RANGE
SOUTH OF GRAND RAPIDS THROUGH ABOUT 23Z. THIS COMBINED WITH TEMPS
IN THE 70S WILL LEAD TO AN ELEVATED FIRE DANGER RISK.

&&

.HYDROLOGY...
ISSUED AT 253 PM EDT FRI MAY 17 2013

LOCALIZED SHOWERS NOT CREATING MUCH QPF THIS
AFTERNOON...GENERALLY UNDER A TENTH OF AN INCH. A HIGHER RISK FOR
HEAVIER SHOWERS WILL ARRIVE BY MONDAY AS GULF MOISTURE WORKS ITS
WAY INTO THE AREA.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...93
AVIATION...93
FIRE WEATHER...MJS
HYDROLOGY...MJS
MARINE...MJS

000
FXUS63 KMQT 171742
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
142 PM EDT FRI MAY 17 2013

.UPDATE...
ISSUED AT 633 AM EDT FRI MAY 17 2013

BAND OF ISOLD SHRA/SPRINKLES EDGING OUT OF MINNESOTA ONTO WESTERN LK
SUPERIOR. H7 FGEN/MOISTURE BAND SUPPORTING THESE COULD CLIP KEWEENAW
SO HAVE INCLUDED SOME SPRINKLES FOR THE MORNING. INCREASED SKY COVER
FOR ALL BUT FAR EAST AS 12-15KFT DECK OF CLOUDS HAS SOLIDIFIED OVER
LAST COUPLE HOURS. WITH MORE CLOUD COVER...TEMPS HAVE BECOME STEADY
OR EVEN SLOWLY RISING. ADJUSTED TEMPS NEXT FEW HOURS. THINNING OUT OF
CLOUDS OVER NORTH STILL POSSIBLE BY AFTN WITH LOSS OF DIVERGENCE
ALOFT. FARTHER SOUTH THE SHOWERS LIFTING NORTH THROUGH WI...AS FAR
NORTH AS KAUW...STILL ON TRACK TO AFFECT VCNTY OF MEMOMINEE AFTER
17Z.
&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT FRI MAY 17 2013

IN CONFLUENT FLOW PATTERN ALOFT EXPECT HIGH PRESSURE TO EXPAND FROM
NORTHERN ONTARIO ACROSS GREAT LAKES TODAY. LIGHT WINDS OVER FAR EAST
ALONG THE RIDGE AXIS AND CLEARER SKIES HAVE ALLOWED TEMPS TO FALL
BLO 30 AT A FEW OF THE FIRE WX RAWS SITES. WARM FRONT STAYS WELL TO
SOUTHWEST OF UPR MICHIGAN TODAY...CURRENTLY FROM CENTRAL PLAINS INTO
NORTHERN OHIO VALLEY...ONLY ADVANCING INTO SOUTHERN MINNESOTA AND
SOUTHERN WISCONSIN BY THIS EVENING. A LOT OF MID CLOUDS OVER THE
UPPER LAKES REGION THIS MORNING. REGIONAL RADAR LOOP SHOWS MULTIPLE
RIBBONS OF SHRA ACROSS NORTHERN MINNESOTA AND ALSO AS FAR NORTH AS
CENTRAL WISCONSIN. BOTH AREAS OF SHOWERS ARE SUPPORTED BY MID-LEVEL
FRONTOGENESIS AND H85-H7 MOISTURE ADVECTION. MORE ORGANIZED CLUSTER
OF SHRA AND NMRS TSRA OCCURRING OVER NORTHERN IA INTO FAR SOUTHERN
MINNESOTA ALONG H85 WARM FRONT/H95 MOISTURE CONVERGENCE AND ON EDGE
OF 1-6KM MUCAPE GRADIENT.

PRIMARY QUESTION IS RAIN POTENTIAL/COVERAGE THROUGH TONIGHT. TO SUM
UP HAVE WENT WITH DRIER FCST FARTHER NORTH INTO UPR MICHIGAN
COMPARED TO WHAT MANY MODELS SHOW. THINKING THAT MAJORITY OF MODELS
ARE OVERDONE WITH PRECIP GIVEN BUILDING SFC-H85 HIGH PRESSURE RIDGE
FROM NORTHERN ONTARIO INTO THE LOWER GREAT LAKES AND LACK OF STRONG
MOISTURE ADVECTION AS FAR NORTH AS UPR MICHIGAN. SHRA OVR NORTHERN
MINNESOTA EXPECTED TO DISSIPATE AS RIGHT ENTRANCE REGION OF JET OVER
ONTARIO FADES THROUGH 15Z. ISLE ROYALE COULD STILL GET CLIPPED WITH
ISOLD SHRA...REST OF WESTERN CWA SHOULD STAY DRY. MEANWHILE...H7
MOISTURE TRANSPORT MARKING EDGE OF SHRA OVER CNTRL WISCONSIN PRETTY
WELL RIGHT NOW. MOISTURE ADVECTION AT H7 AND H8-H7 FRONTOGENESIS IS
FORECAST TO IMPACT FAR SCNTRL CWA BY LATE MORNING AND REST OF THE
DAY. HAVE BROUGHT LOW CHANCE POPS INTO MENOMINEE COUNTY...BUT SHOULD
BE SHARP CUTOFF FARTHER NORTH FOR PRECIP GIVEN DOWNWARD MOTION ON
DECENDING BRANCH OF THE MID-LEVEL FRONTOGENESIS. NAM/GEM-REGIONAL
PROBABLY TOO DRY TODAY OVER THE SOUTHERN CWA...BUT SEEM BETTER FIT
COMPARED TO GFS/ECMWF. SHOULD NOTE THAT EVEN THESE MODELS HAVE
TRENDED FARTHER SOUTH WITH AXIS OF QPF COMPARED TO MODEL RUNS FROM
THURSDAY.

ELSEWHERE...SCT-BKN MID CLOUDS SHOULD BE THE STORY ALONG WITH LGT
EASTERLY SFC WINDS WITH ORIGIN OUT OF SFC HIGH AND WELL TO NORTH OF
THE SFC WARM FRONT. THINNING OF MID CLOUDS OVERHEAD MAY OCCUR AS
RIGHT ENTRANCE REGION FORCING FROM JET OVER ONTARIO DIMINISHES.
TEMPS SHOULD HAVE NON-UNIFORM GRADIENTS DUE TO CLOUDS AND SFC WIND
TRAJECTORIES. WARMEST READINGS AROUND 70 DEGREES IN THE FAR EAST.
COOLEST READINGS IN 50S ALONG LK SUPERIOR WITH PREVAILING ONSHORE
FLOW. MAY ALSO SEE COOLER POCKET OF TEMPS SET UP ALONG WI BORDER DUE
TO THICKER CLOUD COVER AND POTENTIAL PRECIP. UNLIKE LAST FEW
DAYS...H9-H85 LIMITED DRY AIR IN THE H9-H85 LAYER SHOULD PROHIBIT
DEEP MIXING AND VERY LOW HUMIDITIES.

TONIGHT...LARGE SCALE FORCING CHANGES START TO INCREASE CHANCES FOR
PRECIP TO MAKE IT INTO AT LEAST MORE OF UPR MICHIGAN. UPPER LEVEL
TROUGH MOVES INTO NORTHERN ROCKIES WITH SFC-H85 LOWS BECOMING MORE
ORGANIZED OVER NORTHERN PLAINS. WINDS BECOME MORE SOUTHERLY OVER
UPPER MISSISSIPPI RIVER VALLEY IN RESPONSE. H85 BAROCLINIC ZONE
LIFTS TOWARD WESTERN LK SUPERIOR AND NORTHERN WISCONSIN THROUGH THE
NIGHT. ISENTROPIC ASCENT ALONG THE BOUNDARY SUPPORTS CHANCES OF SHRA
INCREASING. SHARPEST MOISTURE TRANSPORT INTO THE H85 BOUNDARY IS
OVER NORTHERN MINNESOTA AND INTO WESTERN LK SUPERIOR...WITH A
TAPERING OFF FARTHER EAST. NOT MUCH H7 MOISTURE ADVECTION FARTHER
EAST EITHER. REALLY PREFER THE GEM-REGIONAL/NAM/NCEP WRF IDEA FOR
CONVECTION TONIGHT...FAVORING MAJORITY OF SHRA/TSRA OVER NORTHERN
MINNESOTA INTO SOUTHWEST UPR MICHIGAN. EDGE OF CAPE GRADIENT ALSO
SUPPORTS BETTER TSRA POTENTIAL INTO SW UPR MICHIGAN FROM LATE
EVENING ONWARD. BY LATE TONIGHT...MAJORITY OF MODELS SHOVE THE
CONVECTION...OR AT LEAST REMNANTS OF IT...INTO CNTRL UPR MICHIGAN.
SUPPOSE THIS MAY OCCUR DO TO LEAD SHORTWAVE PRESSING ACROSS NORTHERN
MINNESOTA AND H7 MOISTURE TRANSPORT VECTORS TURNING MORE WEST TO
EAST. NOT SOLD ON A LOT OF PRECIP MAKING IT WELL TO EAST OF GRADIENT
OF INSTABILITY ALOFT...SO JUST USED SLIGHT CHANCE POPS OTHER THAN
OVER FAR WESTERN CWA. MINS TONIGHT HELD UP BY THICKENING CLOUDS AND
PRECIP. TEMPS OVER INTERIOR EAST MAY DROP INTO 30S...BUT NOT AS COOL
AS EARLY THIS MORNING. 40S TO AROUND 50 FOR MINS EVERYWHERE ELSE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 446 AM EDT FRI MAY 17 2013

NAM SHOWS A 500 MB RIDGE OVER THE UPPER GREAT LAKES 12Z SAT WITH
TROUGHING IN THE ROCKY MOUNTAINS. THE RIDGE REMAINS 12Z SUN WITH A
SHORTWAVE ON THE WESTERN SIDE IN THE DAKOTAS. TROUGHING THEN MOVES
IN THE NORTHERN PLAINS WITH A CLOSED LOW 12Z MON. NAM SHOWS SOME
DEEPER MOISTURE AND Q-VECTOR CONVERGENCE REMAINING OVER THE AREA 12Z
SAT ONWARD.

DID MAKE A MAJOR CHANGE TO THE GOING FORECAST AND WENT DRIER OVER
THE EASTERN HALF OF THE CWA THROUGH SUN NIGHT. AM FINDING IT HARD TO
BELIEVE WITH THE SLOW MOVEMENT OF THE SYSTEM TO THE WEST...BUILDING
UPPER RIDGE TO THE EAST AND A SFC HIGH PRESSURE SYSTEM BRINGING IN
DRY EAST TO SOUTHEAST FLOW...THAT PCPN WOULD BE AS WIDESPREAD AS IT
IS IN THE ECMWF...NAM AND GFS MODELS AND THINK THEY ARE ALL OVERDONE
WITH HIGHER SFC DEW POINTS BEING OVERFORECASTED WHICH HAS BEEN THE
CASE FOR THE PAST SEVERAL WEEKS. WITH HIGHER DEW POINTS BEING
FORECASTED THAN WHAT HAS OCCURRED...THIS WOULD CAUSE MORE WIDESPREAD
QPF THAN WHAT IS ACTUALLY OCCURRING DUE TO CONVECTIVE PARAMETERS
BEING ACTIVATED IN THE MODELS. WITH THIS IN MIND...WILL GO WITH A
DRIER SCENARIO AND CUT POPS BACK WITH CHANCE POPS OVER THE WEST ONLY
THROUGH SUNDAY NIGHT. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO
THE GOING FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER THE
NORTHERN PLAINS 12Z MON WITH A RIDGE OVER THE EASTERN U.S. AND
TROUGHING ACROSS THE PLAINS. PATTERN CHANGES VERY LITTLE FOR 12Z TUE
WITH A SLIGHT EASTWARD MOVEMENT 12Z WED INTO THE UPPER MISSISSIPPI
RIVER VALLEY. THIS LOW AND TROUGH MOVE INTO THE UPPER GREAT LAKES
12Z THU. ONE THING WITH THIS PATTERN IS IT WILL BE SLOW TO PROGRESS
EASTWARD. LOOKS LIKE A DECENT CHANCE FOR WIDESPREAD RAIN STARTING
MON AND LASTING INTO WED AS THE TROUGH KICKS OUT. ON THU...DRIER AIR
STARTS TO WORK IN AS A COLD FRONT HEADS SOUTH WED NIGHT INTO THU AND
POPS SHOULD BE LOWER BY THEN. SHOULD ALSO BE A COOLING TREND THIS
FORECAST PERIOD WITH TEMPERATURES COOLING TO BELOW NORMAL STARTING
TUE ONWARD.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 140 PM EDT FRI MAY 17 2013

WITH A WARM FRONT MOVING INTO THE AREA TONIGHT...EXPECT INCREASING
CHANCES FOR RAIN SHOWERS AND POSSIBLY SOME THUNDER /TOO UNCERTAIN ON
THUNDER TO PUT IN TAF/ TO MOVE IN TONIGHT INTO SAT MORNING. EXPECT
PRIMARY LOWEST CIGS TO BE MVFR WITH LITTLE VIS RESTRICTIONS. CIGS
SHOULD IMPROVE SOME ON SAT DUE TO LOW LEVEL MIXING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...JLA
SHORT TERM...JLA
LONG TERM...07
AVIATION...TITUS
MARINE...07

000
FXUS63 KAPX 171725
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
125 PM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT FRI MAY 17 2013

HIGH PRESSURE WILL REMAIN IN CONTROL OF NORTHERN MICHIGANS WEATHER
THROUGH TODAY...RESULTING IN DRY WEATHER UNDER PARTLY SUNNY SKIES
AND SEASONABLE TEMPERATURES. WARM AND MOIST AIR PRESSING INTO THE
MIDWEST AND GREAT LAKES WILL BRING A CHANCE FOR SHOWERS TO THE
NORTH WOODS OVER THE WEEKEND...MAINLY ON SATURDAY.

&&

.UPDATE...
ISSUED AT 116 PM EDT FRI MAY 17 2013

WELL...HIGH RES RUNS HAVE SHOWN THEIR USEFULNESS...PEGGING
DECAYING MCS REMNANTS OVERSPREADING AREAS ALONG AND SOUTH OF M-72
THIS AFTERNOON. RADAR AND SURFACE TRENDS NO DOUBT BEAR THIS
OUT...WITH LIGHT RAIN REPORTED AT FKS...MBL...AND CAD WITHIN THE
LAST HOUR. THIS LIGHT RAIN SHOULD CONTINUE TO SPREAD EAST...AND
HAVE SIGNIFICANTLY ADJUSTED FORECAST TO SHOW THESE TRENDS. COOL
EAST FLOW AND EXTENSIVE CLOUDS ACROSS NORTHERN LOWER ALSO PLAYING
HAVOC WITH TEMPERATURE TRENDS. READINGS ALREADY WELL SHORT OF WHAT
WAS EARLIER ANTICIPATED. HAVE ADJUSTED THESE DOWNWARD...ALTHOUGH
WHERE RAIN PERSISTS...MAY NOT YET BE COOL ENOUGH.

UPDATE ISSUED AT 936 AM EDT FRI MAY 17 2013

INCREASINGLY CHALLENGING FORECAST DEVELOPING FOR TODAY. UPSTREAM
REMNANT MCS ON LEADING EDGE OF THETA-E ADVECTION/NOSE OF LOW LEVEL
JET CONTINUES TO DRIVE EAST ACROSS SOUTHERN WISCONSIN...WITH SOME
LEADING EDGE RETURNS SPILLING INTO SOUTHWEST SECTIONS OF OUR AREA
(EVEN SOME EVIDENCE OF MID LEVEL FGEN HELPING MAINTAIN/EXPAND THESE
LEADING EDGE SHOWERS). LOW LEVELS REMAIN DRY...AND JUST HAD FIRST
REPORTS OF RAIN REACHING THE SURFACE AT CADILLAC. HAVE ADJUSTED
FORECAST A TOUCH MORE PESSIMISTICALLY SOUTH OF TRAVERSE
CITY...ALTHOUGH TRENDS SUGGEST PERHAPS NOT PESSIMISTICALLY ENOUGH.
LATEST HIGH RES HRRR SOMEWHAT DISCONCERTING...DRIVING DECAYING MCS
ACROSS THE SOUTH HALF OF THE AREA THIS AFTERNOON...PRODUCING RATHER
WIDESPREAD LIGHT SHOWERS. PERUSAL OF OTHER GUIDANCE AND MODEL
DERIVED SOUNDINGS SUGGEST OTHERWISE...WITH DEEP LOW LEVEL DRY LAYER
AND LOSS OF DYNAMICS ESSENTIALLY FULLY DECAYING THIS ACTIVITY BEFORE
IT REACHES OUR AREA. THAT SAID...RADAR RETURNS MORE THAN
OMINOUS...AND DEFINITE FUTURE CHANGES MORE THAN EXPECTED. MORE
CLOUDS/RAIN WOULD ALSO MEAN SIGNIFICANTLY COOLER TEMPERATURES ACROSS
THE SOUTH. WILL CONTINUE TO MONITOR.

UPDATE ISSUED AT 606 AM EDT FRI MAY 17 2013

FORECAST APPEARS ON TRACK FOR THE MOMENT. SUBSTANTIAL HIGH CLOUDS
FROM UPSTREAM CONVECTION HAVE OVERSPREAD MUCH OF THE CWA...
ESPECIALLY NRN LOWER MICHIGAN. SATELLITE TRENDS REVEAL ABUNDANT
HIGHER CLOUD COVER UPSTREAM THAT WILL CONTINUE TO STREAM THROUGH
THE REGION TODAY. THUS PARTLY SUNNY TO OCCASIONALLY MOSTLY CLOUDY
SKIES SHOULD WORK OUT.

OTHERWISE...QUITE A FEW LOCATIONS ARE IN THE UPPER 30S WITH A FEW
SPOTS COLDER (PLN IS 32F). WARMEST LOCATIONS ARE IN THE SW
COUNTIES (TVC/FKS/MBL...ETC). CAN PROBABLY SAFELY TRIM THOSE
COUNTIES OUT OF THE FREEZE ADVISORY EARLY.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT FRI MAY 17 2013

OVERVIEW: FAIRLY PROGRESSIVE FLOW PATTERN ACROSS THE CONUS CURRENTLY
BUT STARTING TO BECOME MORE AMPLIFIED AS TROUGHINESS DEEPENS ALONG
THE WEST COAST...AND DOWNSTREAM RIDGING BUILDS THROUGH THE PLAINS
AND INTO THE GREAT LAKES. RIDGING GRADUALLY BUILDS INTO THE GREAT
LAKES HEADING THROUGH THE WEEKEND SIGNALING WARMER DAYS AHEAD.

MEANWHILE...HIGH PRESSURE HAS NUDGED IT/S WAY DOWN OUT OF ONTARIO
AND INTO THE WESTERN GREAT LAKES. ONGOING MCS ACTIVITY TO OUR
SOUTHWEST ACROSS IOWA...BUT WILL STAY WELL AWAY FROM US AS
MOISTURE/INSTABILITY REMAINS DISPLACED WELL OFF TO OUR WEST AND SOUTH.

TODAY...HIGH PRESSURE AND ANTECEDENT DRY AIRMASS WILL CONTINUE TO
DOMINATE THE REGION WITH NO PRECIP ANTICIPATED. HOWEVER...THERE IS
QUITE A BIT OF MID AND HIGH CLOUD COVER UPSTREAM FROM ONGOING
CONVECTION AS WELL AS INCREASING WARM ADVECTION ACROSS THE PLAINS.
THUS...WILL SEE VARIOUS ROUNDS OF MID AND HIGH CLOUD SLIDING THROUGH
THE REGION...LEADING TO PARTLY CLOUDY TO OCCASIONALLY MOSTLY CLOUDY
SKIES. TEMPERATURES...A LITTLE WARMER AS COMPARED TO THURSDAY WITH
HIGHS RANGING FROM THE MID 60S TO LOWER 70S.

FIRE WEATHER CONCERNS...DRY ANTECEDENT CONDITIONS PERSIST AND EXPECT
INLAND SFC DEWPOINTS WILL DIP INTO THE LOWER 30S DURING THE
AFTERNOON LIKE THURSDAY WITH MINIMUM RH VALUES GOING BELOW 25
PERCENT. HOWEVER...TEMPS WILL LARGELY REMAIN BELOW 75 FOR MOST AREAS
AND WINDS WILL BE FAIRLY LIGHT (UNDER 10 MPH). YES IT WILL BE DRY
BUT WITHOUT DECENT WIND...WILL NOT HAVE ELEVATED FIRE DANGER
MENTIONED IN THE HWO FOR TODAY.

TONIGHT...WARM AND MOIST AIR (HIGH THETA-E) BUILDS THROUGH THE
PLAINS AND THE UPPER MIDWEST THROUGH THE COURSE OF THE NIGHT WITH
THE STRONGEST SURGE/FORCING OCCURRING ACROSS THE NRN PLAINS AND UPPER
MIDWEST WHERE ONE OR MORE CONVECTIVE SYSTEMS WILL LIKELY BE ONGOING
OR DEVELOP. HERE AT HOME...NOT SO IMPRESSED. NW-SE ORIENTED THETA-E
GRADIENT WILL BE INCHING UP THROUGH STATE THROUGH THE COURSE OF THE
NIGHT. BUT AGAIN...MUCH STRONGER LOW LEVEL FLOW AND RESULTING
FORCING (MOIST CONVERGENCE) WILL REMAIN WELL WEST-NORTHWEST OF THE
CWA WHERE MOST CONVECTIVE ACTIVITY WILL BE CONFINED. SUPPOSE ITS
PLAUSIBLE WE GET A FEW ELEVATED SHOWERS TO DEVELOP ALONG THE
ADVANCING THETA-E GRADIENT ALTHOUGH LAPSE RATES ALOFT ARE JUST NOT
THAT SUPPORTIVE OF CONVECTION. IN THE END...FOR CONTINUITY AND
COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO MAINTAIN CHANCE
POPS FOR SHOWERS OVER NW LOWER MICHIGAN OVERNIGHT BUT HAVE TRIMMED
POPS BACK TO 30 PERCENT OR LESS.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM EDT FRI MAY 17 2013

A WARMER AND PROGRESSIVELY MORE MOIST SOUTHEASTERLY FLOW WILL LEAD
TO CHANCES FOR SHOWERS THIS WEEKEND. THERE WILL BE CHANCES FOR
SHOWERS AND EVEN THUNDERSTORMS EARLY NEXT WEEK WHICH WILL BECOME
LIKELY BY THE MIDDLE OF NEXT WEEK...AS A CUTOFF UPPER TROUGH
APPROACHES FROM OUR SOUTHWEST. FINALLY...CONDITIONS MOST LIKELY  DRY
OUT BY THURSDAY AS THIS SYSTEM RETREATS TO THE SOUTHEAST. THE MAIN
LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS AND HOW MUCH IT WILL
WARM UP THIS WEEKEND INTO EARLY NEXT WEEK.

SATURDAY AND SUNDAY...MODELS ARE ONLY IN FAIR AGREEMENT ON THE
TIMING AND AMOUNT OF MOISTURE ADVECTION INTO THE REGION AS THETA-E
RIDGING APPROACHES THE FORECAST AREA BUT WEAKENS AS IT DOES SO. THIS
IS IN RESPONSE TO A DECAYING AREA OF LOW PRESSURE MOVING BY TO THE
NORTHWEST. IT IS STILL UNCERTAIN IF IT WILL MOISTEN UP ENOUGH ACROSS
NORTHERN MICHIGAN TO ACTUALLY RAIN...AS THE MAIN ACTION LOOKS TO
REMAIN TO OUR WEST. SO WILL BACK OFF ON POPS TO SLIGHT AND LOW
CHANCES FOR SHOWERS. HIGHS SATURDAY RANGING FROM THE MIDDLE 60S TO
MIDDLE 70S...WITH THE WARMER 70S TO LOWER 80S ON SUNDAY EXPECTED.
LOWS SATURDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.

MONDAY THROUGH THURSDAY...SHOWERS AND THUNDERSTORM CHANCES INCREASE
MONDAY THEN BECOME LIKELY MONDAY NIGHT INTO WEDNESDAY AS A CUTOFF
UPPER LEVEL TROUGH AND WARM FRONT APPROACH FROM THE SOUTHWEST.
EXTENDED MODELS THEN VARY ON THE TIMING OF DRYING FROM THE
NORTH...BUT WILL PENCIL THURSDAY IN AS A DRY DAY AS THIS SYSTEM IS
SHOWN TO SLOWLY RETREAT TO OUR SOUTHEAST. REMAINING WARM WITH HIGHS
IN THE 70S TO LOWER 80S MONDAY...FOLLOWED BY A SLOW COOLING TREND
WITH TEMPERATURES ENDING UP IN THE UPPER 50S TO LOWER 60S FOR HIGHS
BY THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 116 PM EDT FRI MAY 17 2013

VFR CONDITIONS EXPECTED. EXTENSIVE DECK OF HIGH AND MID LEVEL
CLOUDS WILL CONTINUE TO AFFECT ALL TAF SITES RIGHT INTO SATURDAY
MORNING. LIGHT RAINS ALREADY OCCURRING AT KMBL...AND SHOULD
CONTINUE TO DO SO FOR THE NEXT FEW HOURS. RAINS MAY EDGE NORTH TO
TVC LATER THIS AFTERNOON...ALTHOUGH WITH NO IMPACT TO VIS. LIGHT
WINDS WILL REMAIN ACROSS THE AREA.

&&

.MARINE...
ISSUED AT 352 AM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TODAY AND TONIGHT
WITH NO MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES
SATURDAY AND SATURDAY NIGHT AND A HANDFUL OF SMALL CRAFT ADVISORIES
MAY BE NEEDED. AT THAT TIME.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...MB
SYNOPSIS...AS
SHORT TERM...BA
LONG TERM...AS
AVIATION...MB
MARINE...BA

000
FXUS63 KGRR 171704
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
104 PM EDT FRI MAY 17 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 334 AM EDT FRI MAY 17 2013

MORE CLOUDS WILL MOVE INTO THE AREA TODAY AS A SYSTEM TO OUR WEST
TRIES TO MOVE IN. DRY LOW LEVELS WILL KEEP RAIN CHANCES NEAR ZERO
FOR THE AREA. SOME LOW CHANCES OF RAIN WILL BE POSSIBLE TONIGHT AND
EARLY SATURDAY AS A FRONTAL SYSTEM MOVES BY JUST NORTHWEST OF THE
AREA. CONDITIONS SHOULD CLEAR OUT A BIT FOR LATER SATURDAY AND
SUNDAY WITH WARM TEMPERATURES EXPECTED. BETTER CHANCES FOR RAINFALL
WILL COME TOWARD MONDAY AND LINGER THROUGH WEDNESDAY NEXT WEEK.

&&

.UPDATE...
ISSUED AT 1121 AM EDT FRI MAY 17 2013

PRECIPITATION MOVING OFF THE WI SHORELINE HAS BEEN SLOW TO
DIMINISH. GFS 06Z RUN SEEMED TO HAVE A BETTER HANDLE ON THE
PRECIPITATION THAN THE NEW NAM. HRRR 12Z RUN AND OLD GFS PAINT
PRECIPITATION ACROSS MUCH OF NRN ZONES...NORTH OF MKG TO GRR WITH
PRECIPITAITON THIS AFTERNOON. WILL BUMP UP POPS AND LOWER
TEMPERATURES FOR THIS REGION.

UPDATE ISSUED AT 949 AM EDT FRI MAY 17 2013

ADDED A FEW RAIN SHOWERS TO THE FORECAST FOR LUDINGTON TO NEAR
CADILLAC. RADAR TRENDS SHOW INCREASING RETURNS AND THE OBSERVATION
OUT OF CADILLAC INDICATED THAT THE PRECIPITATION WAS REACHING THE
GROUND. AM MONITORING THE WEAKENING THUNDERSTORMS OVER IN ERN
WISCONSIN. MAY NEED TO ADD SOME PRECIPITATION TO THE MUSKEGON
FORECAST AS WELL IF THEY DO NOT WEAKEN QUICKLY ENOUGH. I DID
ADJUST TEMPERATURES DOWNWARD SLIGHTLY FOR NORTHERN ZONES DUE TO
THE CLOUDS AND PRECIPITATION.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

THE MAIN CHALLENGE IN THE SHORT TERM IS DETERMINING PCPN CHCS
THROUGH THE PERIOD. MOST OF THE PERIOD THROUGH THE WEEKEND LOOKS
DRY...HOWEVER THERE ARE A COUPLE OF PERIODS WHERE RAIN POTENTIAL HAS
TO BE ADDRESSED.

WE EXPECT THAT THE AREA WILL STAY DRY DURING THE DAY TODAY. HIGH
CLOUDS STREAMING IN FROM THE WEST ARE SHROUDING THE AREA PRETTY WELL
THIS MORNING. SOME MID CLOUD COVER IS SHOWING UP OVER WEST CENTRAL
AREAS OF THE CWFA. THERE IS SOME MOISTURE TRANSPORT/THETA E
ADVECTION TAKING PLACE IN THE MID LEVELS. THE BEST PUSH OF EACH IS
OCCURRING FURTHER WEST IN WI. IN ADDITION...THE EASTERLY FLOW IS
CONTINUING TO FEED DRIER AIR IN ACROSS THE AREA. THESE FACTORS
SHOULD KEEP THE ENTIRE AREA DRY TODAY. TEMPS WILL LIKELY BE A COUPLE
OF DEGREES COOLER TODAY WITH LESS SOLAR INSOLATION.

THE FIRST CHC OF RAIN THAT COULD OCCUR WOULD BE DURING THE PERIOD
FROM TONIGHT INTO SAT MORNING ACROSS THE N/NW COUNTIES. WE HAVE
ADDED A SLIGHT CHC OF SHOWERS TO THE N/NW COUNTIES. THE BEST MID
LEVEL THETA E ADVECTION/MOISTURE TRANSPORT CONTINUES TO BE W/NW OF
THE AREA. THERE ARE SOME SOLUTIONS SHOWING THERE COULD BE JUST
ENOUGH FORCING AND DEEP ENOUGH MOISTURE TO GENERATE ENOUGH PCPN TO
REACH THE GROUND THROUGH THE DRIER LOWER LEVELS.

BY SAT AFTERNOON...WE SEE SUFFICIENT DIGGING OF THE WRN TROUGH AND
RESULTANT BUILDING OF THE UPPER RIDGE OVER THE AREA TO PUSH THE
CLOUDS AND PCPN WELL NORTH OF THE CWFA. MORE SUNSHINE COMPARED TO
THIS AFTERNOON WILL HELP TO WORK ON THE WARMING H850 TEMPS TO AROUND
12-13C AND SUPPORT HIGHS AROUND 80. THE LOW LEVEL FLOW WILL BE
VEERING A BIT TO THE S/SE AS THE HUDSON BAY RIDGE SHIFTS EAST. THIS
WILL HELP TO START ADVECTING SOMEWHAT HIGHER DEW POINTS INTO THE
AREA. FCST SOUNDINGS SHOW THAT THE LOW LEVELS WILL STILL BE JUST A
LITTLE TOO DRY YET TO ALLOW FOR ANY POP UP DIURNAL CONVECTION ALONG
ANY BOUNDARIES.

WE WILL SEE MORE SUNSHINE ON SUN WITH TEMPS INCREASING A CATEGORY AS
TEMPS ALOFT UNDER THE RIDGE INCREASE A COUPLE OF DEGREES C. SUN
MIGHT SEE A SLIGHTLY BETTER CHC FOR A POP UP SHOWER DURING THE
AFTERNOON HOURS AS BETTER LOW LEVEL MOISTURE DOES ADVECT IN. FCST
SOUNDINGS INDICATE THAT THE MID AND UPPER LEVELS MAY BE JUST A TAD
TOO WARM YET WITH THE UPPER RIDGE OVERHEAD TO ALLOW SHOWERS TO FORM.
THE CHC IS NOT ZERO...HOWEVER IT LOOKS JUST A LITTLE TOO LOW AT THIS
TIME TO JUSTIFY ADDING IN THE CHC.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

LONG TERM PATTERN BEGINS WITH THE UPPER RIDGE OVERHEAD AND AN UPPER
LOW ACROSS THE NORTHERN PLAINS. THE RIDGE GRADUALLY SHIFTS SOUTH AND
EAST ALLOWING THE GREAT LAKES TO BECOME MORE UNDER THE INFLUENCE OF
THE UPPER LOW NEXT WEEK. THE UPPER LOW FILLS WITH TIME AND BECOMES
ABSORBED INTO A EASTERN CANADIAN UPPER TROUGH. BOTH THE GFS AND
ECMWF PAINT THIS SCENARIO.

AT THE SURFACE LOW PRESSURE WILL GRADUALLY MOVE INTO THE GREAT LAKES
STATES FROM THE WEST INTO MID WEEK. ISOLATED SHOWERS AND STORMS
APPEAR POSSIBLE SUNDAY NIGHT...WITH CHANCES RAMPING UP TO LIKELY
FROM TUESDAY INTO WEDNESDAY AS THE LOW AND A SURFACE WARM FRONT WILL
BE IN THE AREA. THE THUNDER THREAT DIMINISHES INTO WEDNESDAY NIGHT
AND THURSDAY AND HAVE SHOWERS ONLY IN THE FORECAST DURING THESE
PERIODS.

THE LONG TERM PERIOD LOOKS TO BE WET OVERALL...WITH RAINFALL IN
EXCESS OF AN INCH POSSIBLE AS THE UPPER LOW SLOWLY MOVES THROUGH THE
REGION. TEMPERATURES WILL START OUT WARM IN SOUTHERLY
FLOW...TRENDING BACK TOWARD NORMAL INTO MID WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 104 PM EDT FRI MAY 17 2013

A STATIONARY FRONT OVER LOWER MICHIGAN WILL CONTINUE TO BE A FOCUS
FOR A MID CLOUD DECK THROUGH THE PERIOD. SHOWERS SEEN ON CURRENT
RADAR WILL MOSTLY STAY NORTH OF THE TAF SITES. HOWEVER A SPRINKLE
OR TWO CAN/T BE RULED OUT A KMKG BUT THE PROBABILITY WAS LOW
ENOUGH TO LEAVE OUT OF THE TAFS.

&&

.MARINE...
ISSUED AT 1121 AM EDT FRI MAY 17 2013

EXPANDED THE MENTION OF RAIN IN THE FORECAST FOR NORTHERN MARINE
ZONES.


&&

.FIRE WEATHER...
ISSUED AT 334 AM EDT FRI MAY 17 2013

CONDITIONS LOOK TO BE A SLIGHT BIT BETTER THAN THU WITH REGARD TO
FIRE DANGER...ALTHOUGH THE FIRE DANGER WILL REMAIN ELEVATED. MORE
CLOUD COVER WILL LIMIT THE AMOUNT OF HEATING AND THE MIXING DOWN OF
DRIER AIR. CONDITIONS WILL ONCE AGAIN APPROACH RED FLAG CRITERIA...
HOWEVER WE EXPECT RH/S TO REMAIN JUST SHY OF THE RED FLAG
CRITERIA....WINDS TO REMAIN JUST UNDER CRITERIA WITH A FEW GUSTS TO
NEAR CRITERIA...AND TEMPS RIGHT AROUND THE THRESHOLD OF 75 DEGREES.
WE WILL NEED TO MONITOR THE SITUATION THIS AFTERNOON.

DEW POINTS SHOULD COME UP SOME OVER THE WEEKEND AS THE FLOW BECOMES
A LITTLE MORE SOUTHERLY AND MOISTURE WILL ADVECT INTO THE AREA. THIS
SHOULD KEEP RED FLAG CRITERIA FROM BEING REACHED.

&&

.HYDROLOGY...
ISSUED AT 334 AM EDT FRI MAY 17 2013

WE WILL NOT SEE ANY HYDROLOGY ISSUES THROUGH THE WEEKEND WITH LIKELY
NO RAIN AT ALL. THE CHANCES OF ANY HYDROLOGY ISSUES MON-WED NEXT
WEEK WITH RAINFALL WITH THE SYSTEM DO NOT LOOK THAT GREAT EITHER.
THE SURFACE OF THE SOIL AROUND THE AREA HAS DRIED CONSIDERABLY...AND
RIVER/STREAM LEVELS HAVE RETURNED TO NEAR AVERAGE FLOWS. THE MODELS
ARE SHOWING RAINFALL AMOUNTS OF OVER AN INCH POSSIBLE FROM MON-WED.
THIS SHOULD NOT ALL COME AT ONCE...AND THE GROUND SHOULD SOAK IT UP
PRETTY WELL. RIVER LEVELS WILL COME UP...HOWEVER WE DO NOT EXPECT
ANY NOTABLE ISSUES AT THIS TIME.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...93
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...MJS

000
FXUS63 KDTX 171651
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1251 PM EDT FRI MAY 17 2013


.AVIATION...

//DISCUSSION...

HIGH PRESSURE TO THE NORTH AND AN ABUNDANCE OF LOW-LEVEL DRY AIR
WILL SUSTAIN LIGHT/STABLE EASTERLY FLOW AND VFR CONDITIONS THROUGH
THE TAF PERIOD. CONVECTIVE ACTIVITY OVER WISCONSIN IS NOT EXPECTED
TO SURVIVE ITS TREK EAST, ALTHOUGH PERIODS OF MID/HIGH CLOUDS ABOVE
5KFT CAN BE EXPECTED AS THE ASSOCIATED CLOUD COVER IS DRAWN
EASTWARD. FAR NORTH AND WEST LOCATIONS SUCH AS KMBS MAY SEE A BRIEF
PERIOD OF LIGHT RAINFALL OUT OF THIS ACTIVITY WITH NO RESTRICTION TO
VISIBILITY, WHILE REMAINING LOCATIONS WILL STAY DRY WITH PASSING MID
AND HIGH CLOUDS. IMPROVING MID-LEVEL MOISTURE QUALITY WILL BRING A
CHANCE FOR A CEILING BELOW 5KFT BY MORNING, BUT CONFIDENCE REMAINS
QUITE LOW AS STABILITY AND DRY AIR IN THE LOWEST 6KFT ARE EXPECTED
TO REMAIN LARGELY DOMINANT.

//DTW THRESHOLD THREATS...

* LOW CONFIDENCE IN CEILINGS BELOW 5KFT ON SATURDAY MORNING

&&

.PREV DISCUSSION...ISSUED 345 AM EDT FRI MAY 17 2013

SHORT TERM...TODAY AND TONIGHT

QUIET DAY IN STORE AS WE REMAIN UNDER THE SOUTHERN PERIPHERY OF
CANADIAN HIGH PRESSURE AT THE SFC WITH MID LEVEL HEIGHTS BUILDING
THROUGH THE DAY. LOOKING ALOFT...THERE ARE TWO DISTURBANCES TRYING
TO MOVE INTO THE GREAT LAKES. THE FIRST IS A CLOSED MID LEVEL LOW
DRIFTING THROUGH THE CENTRAL CONUS WITH A SLIGHT NE TRAJECTORY
TOWARD THE OHIO VALLEY. THE SECOND IS A SHORTWAVE ROUNDING THE APEX
OF THE MID LEVEL RIDGE OVER IA/MN/WI. MOST MODELS KEEP THE FIRST TO
OUR SOUTH AND TAKE THE LATTER ON A NE TRACK THROUGH NORTHERN MI.
MANY MODELS...KEEP SE MI DRY THROUGH TONIGHT BUT THE NAM/GFS STILL
HANG ONTO A SOME PRECIP AFTER MIDNIGHT TONIGHT. WITH A CONSTANT FEED
OF DRY AIR IN THE LOW LEVELS WITH THE NE FLOW FROM THE SFC
HIGH...BOTH SYSTEM WILL HAVE A TOUGH TIME GETTING ANY PRECIP TO HIT
THE GROUND. THERE IS A BAND OF ELEVATED FGEN NEAR THE 700MB THETA E
GRADIENT WHICH HAS BEEN PRODUCING SHOWERS TO OUR WEST AND WHICH THE
TAIL END WILL SWEEP NORTHWARD THROUGH THE SAGINAW VALLEY. THIS IS
ENOUGH TO KEEP SOME MENTION OF SHOWERS WHILE GIVING THE DAY CREW A
CHANCE TO LOOK AT HIRES MODELS TODAY AND GET A BETTER HANDLE OF
THINGS. SHIFTED THE INHERITED SLIGHT CHANCE NORTH ACROSS THE SAGINAW
VALLEY AND THUMB AS THIS REGION STAND THE BEST CHANCE OF SATURATING
LATE TONIGHT. THE POSITIONING OF THE SFC RIDGE WILL LEAD TO EASTERLY
WINDS THROUGH TONIGHT WHICH WILL KNOCK TEMPS DOWN A BIT FROM THE
LAST FEW DAYS...EVEN MORE FOR LOCATIONS CLOSE TO THE LAKE HURON
SHORELINE. ADDITIONALLY...THE MID AND HIGH CLOUDS STREAMING INTO THE
REGION FROM THE MIDWEST SHORTWAVE WILL HELP KEEP INSOLATION FROM
MAXIMIZING.

LONG TERM...SATURDAY THROUGH THURSDAY

LONGWAVE RIDGE WILL AMPLIFY DURING THE WEEKEND AND KEEP THE WEATHER
RELATIVELY QUIET ACROSS THE CENTRAL GREAT LAKES. ALTHOUGH THERE IS
AN OUTSIDE CHANCE OF AN ISOLATED SHOWER...CONDITIONS ARE EXPECTED TO
BE DRY AND STABLE. EASTERLY SURFACE WINDS AND ABUNDANT MID TO HIGH
LEVEL CLOUDS UNDERNEATH THE RIDGE WILL KEEP TEMPERATURES IN THE 70S
ON SATURDAY. WINDS WILL TURN SOUTHERLY ON SUNDAY AS THE SURFACE
RIDGE HEADS OFF TO THE EAST WITH HIGH TEMPERATURES TOPPING OUT
AROUND 80 DEGREES SUNDAY AFTERNOON.

A LONGWAVE TROUGH...CURRENTLY SHOWN ON WATER VAPOR IMAGERY MAKING
LANDFALL ON THE CALIFORNIA COAST...WILL CONTROL THE WEATHER FOR MUCH
OF NEXT WEEK. THIS LONGWAVE TROUGH IS FORECAST TO MOVE EAST DURING
THE WEEKEND...EMERGING EAST OF THE ROCKIES ON MONDAY AND CLOSING OFF
ACROSS THE NORTHERN PLAINS. ALTHOUGH THERE IS UNCERTAINTY REGARDING
THE PLACEMENT OF THE AFOREMENTIONED LOW...THERE SEEMS TO BE A
CONSENSUS IN GENERATING QUITE A BIT OF SHOWERS AND THUNDERSTORMS AS
A WARM STABLE ATMOSPHERE SETTLES OVER THE CENTRAL GREAT LAKES DURING
THE MONDAY THROUGH WEDNESDAY TIME FRAME. DURING THIS TIME FRAME
MUCAPE VALUES RISE TO 1000 TO 2000 J/KG...INCREASING THE THREAT FOR
ORGANIZED THUNDERSTORM ACTIVITY. HODOGRAPHS ARE RATHER UNIMPRESSIVE
ON MONDAY WITH A NEARLY UNIDIRECTIONAL SOUNDING. THERE ARE BETTER
HODOGRAPHS TUESDAY AND WEDNESDAY AS THE LOW ITSELF TRACKS THROUGH
THE REGION. HOWEVER WITH THE LOW TRACK BEING UNCERTAIN THE THREAT
FOR SEVERE THUNDERSTORMS IS UNCERTAIN GIVEN THE SHEAR VALUES ARE
VASTLY DIFFERENT DEPENDING ON THE TRACK OF THE LOW. ALTHOUGH THE
SITUATION BEARS CLOSE ATTENTION...THERE IS NOT ENOUGH CONFIDENCE
EITHER WAY REGARDING SEVERE POTENTIAL NEXT WEEK.

TEMPERATURES TAKE A NOTABLE TUMBLE BEHIND THE DEPARTING LOW ON
THURSDAY AS 850 MB TEMPERATURES FALL BACK INTO THE SINGLE DIGITS
ABOVE ZERO. THIS WOULD BRING HIGH TEMPERATURES BACK DOWN BELOW
NORMAL LATE NEXT WEEK WITH HIGH TEMPERATURES IN THE 60S.

MARINE...

THE SOUTHERN PERIPHERY OF A CANADIAN HIGH PRESSURE SYSTEM WILL
PRODUCE LIGHT NORTHEASTERLY WINDS OVER THE GREAT LAKES TODAY. WINDS
WILL VEER MORE EASTERLY ON SATURDAY AND SOUTHEASTERLY SUNDAY BUT
WILL REMAIN LIGHT. THIS WILL LEAD TO FAVORABLE MARINE CONDITIONS
THROUGH THE WEEKEND AS THE HIGH SLOWLY WORKS ACROSS THE REGION.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....JVC
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KGRR 171524
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1124 AM EDT FRI MAY 17 2013

LATEST UPDATE...
UPDATE/MARINE

.SYNOPSIS...
ISSUED AT 334 AM EDT FRI MAY 17 2013

MORE CLOUDS WILL MOVE INTO THE AREA TODAY AS A SYSTEM TO OUR WEST
TRIES TO MOVE IN. DRY LOW LEVELS WILL KEEP RAIN CHANCES NEAR ZERO
FOR THE AREA. SOME LOW CHANCES OF RAIN WILL BE POSSIBLE TONIGHT AND
EARLY SATURDAY AS A FRONTAL SYSTEM MOVES BY JUST NORTHWEST OF THE
AREA. CONDITIONS SHOULD CLEAR OUT A BIT FOR LATER SATURDAY AND
SUNDAY WITH WARM TEMPERATURES EXPECTED. BETTER CHANCES FOR RAINFALL
WILL COME TOWARD MONDAY AND LINGER THROUGH WEDNESDAY NEXT WEEK.

&&

.UPDATE...
ISSUED AT 1121 AM EDT FRI MAY 17 2013

PRECIPITATION MOVING OFF THE WI SHORELINE HAS BEEN SLOW TO
DIMINISH. GFS 06Z RUN SEEMED TO HAVE A BETTER HANDLE ON THE
PRECIPITATION THAN THE NEW NAM. HRRR 12Z RUN AND OLD GFS PAINT
PRECIPITATION ACROSS MUCH OF NRN ZONES...NORTH OF MKG TO GRR WITH
PRECIPITAITON THIS AFTERNOON. WILL BUMP UP POPS AND LOWER
TEMPERATURES FOR THIS REGION.

UPDATE ISSUED AT 949 AM EDT FRI MAY 17 2013

ADDED A FEW RAIN SHOWERS TO THE FORECAST FOR LUDINGTON TO NEAR
CADILLAC. RADAR TRENDS SHOW INCREASING RETURNS AND THE OBSERVATION
OUT OF CADILLAC INDICATED THAT THE PRECIPITATION WAS REACHING THE
GROUND. AM MONITORING THE WEAKENING THUNDERSTORMS OVER IN ERN
WISCONSIN. MAY NEED TO ADD SOME PRECIPITATION TO THE MUSKEGON
FORECAST AS WELL IF THEY DO NOT WEAKEN QUICKLY ENOUGH. I DID
ADJUST TEMPERATURES DOWNWARD SLIGHTLY FOR NORTHERN ZONES DUE TO
THE CLOUDS AND PRECIPITATION.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

THE MAIN CHALLENGE IN THE SHORT TERM IS DETERMINING PCPN CHCS
THROUGH THE PERIOD. MOST OF THE PERIOD THROUGH THE WEEKEND LOOKS
DRY...HOWEVER THERE ARE A COUPLE OF PERIODS WHERE RAIN POTENTIAL HAS
TO BE ADDRESSED.

WE EXPECT THAT THE AREA WILL STAY DRY DURING THE DAY TODAY. HIGH
CLOUDS STREAMING IN FROM THE WEST ARE SHROUDING THE AREA PRETTY WELL
THIS MORNING. SOME MID CLOUD COVER IS SHOWING UP OVER WEST CENTRAL
AREAS OF THE CWFA. THERE IS SOME MOISTURE TRANSPORT/THETA E
ADVECTION TAKING PLACE IN THE MID LEVELS. THE BEST PUSH OF EACH IS
OCCURRING FURTHER WEST IN WI. IN ADDITION...THE EASTERLY FLOW IS
CONTINUING TO FEED DRIER AIR IN ACROSS THE AREA. THESE FACTORS
SHOULD KEEP THE ENTIRE AREA DRY TODAY. TEMPS WILL LIKELY BE A COUPLE
OF DEGREES COOLER TODAY WITH LESS SOLAR INSOLATION.

THE FIRST CHC OF RAIN THAT COULD OCCUR WOULD BE DURING THE PERIOD
FROM TONIGHT INTO SAT MORNING ACROSS THE N/NW COUNTIES. WE HAVE
ADDED A SLIGHT CHC OF SHOWERS TO THE N/NW COUNTIES. THE BEST MID
LEVEL THETA E ADVECTION/MOISTURE TRANSPORT CONTINUES TO BE W/NW OF
THE AREA. THERE ARE SOME SOLUTIONS SHOWING THERE COULD BE JUST
ENOUGH FORCING AND DEEP ENOUGH MOISTURE TO GENERATE ENOUGH PCPN TO
REACH THE GROUND THROUGH THE DRIER LOWER LEVELS.

BY SAT AFTERNOON...WE SEE SUFFICIENT DIGGING OF THE WRN TROUGH AND
RESULTANT BUILDING OF THE UPPER RIDGE OVER THE AREA TO PUSH THE
CLOUDS AND PCPN WELL NORTH OF THE CWFA. MORE SUNSHINE COMPARED TO
THIS AFTERNOON WILL HELP TO WORK ON THE WARMING H850 TEMPS TO AROUND
12-13C AND SUPPORT HIGHS AROUND 80. THE LOW LEVEL FLOW WILL BE
VEERING A BIT TO THE S/SE AS THE HUDSON BAY RIDGE SHIFTS EAST. THIS
WILL HELP TO START ADVECTING SOMEWHAT HIGHER DEW POINTS INTO THE
AREA. FCST SOUNDINGS SHOW THAT THE LOW LEVELS WILL STILL BE JUST A
LITTLE TOO DRY YET TO ALLOW FOR ANY POP UP DIURNAL CONVECTION ALONG
ANY BOUNDARIES.

WE WILL SEE MORE SUNSHINE ON SUN WITH TEMPS INCREASING A CATEGORY AS
TEMPS ALOFT UNDER THE RIDGE INCREASE A COUPLE OF DEGREES C. SUN
MIGHT SEE A SLIGHTLY BETTER CHC FOR A POP UP SHOWER DURING THE
AFTERNOON HOURS AS BETTER LOW LEVEL MOISTURE DOES ADVECT IN. FCST
SOUNDINGS INDICATE THAT THE MID AND UPPER LEVELS MAY BE JUST A TAD
TOO WARM YET WITH THE UPPER RIDGE OVERHEAD TO ALLOW SHOWERS TO FORM.
THE CHC IS NOT ZERO...HOWEVER IT LOOKS JUST A LITTLE TOO LOW AT THIS
TIME TO JUSTIFY ADDING IN THE CHC.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

LONG TERM PATTERN BEGINS WITH THE UPPER RIDGE OVERHEAD AND AN UPPER
LOW ACROSS THE NORTHERN PLAINS. THE RIDGE GRADUALLY SHIFTS SOUTH AND
EAST ALLOWING THE GREAT LAKES TO BECOME MORE UNDER THE INFLUENCE OF
THE UPPER LOW NEXT WEEK. THE UPPER LOW FILLS WITH TIME AND BECOMES
ABSORBED INTO A EASTERN CANADIAN UPPER TROUGH. BOTH THE GFS AND
ECMWF PAINT THIS SCENARIO.

AT THE SURFACE LOW PRESSURE WILL GRADUALLY MOVE INTO THE GREAT LAKES
STATES FROM THE WEST INTO MID WEEK. ISOLATED SHOWERS AND STORMS
APPEAR POSSIBLE SUNDAY NIGHT...WITH CHANCES RAMPING UP TO LIKELY
FROM TUESDAY INTO WEDNESDAY AS THE LOW AND A SURFACE WARM FRONT WILL
BE IN THE AREA. THE THUNDER THREAT DIMINISHES INTO WEDNESDAY NIGHT
AND THURSDAY AND HAVE SHOWERS ONLY IN THE FORECAST DURING THESE
PERIODS.

THE LONG TERM PERIOD LOOKS TO BE WET OVERALL...WITH RAINFALL IN
EXCESS OF AN INCH POSSIBLE AS THE UPPER LOW SLOWLY MOVES THROUGH THE
REGION. TEMPERATURES WILL START OUT WARM IN SOUTHERLY
FLOW...TRENDING BACK TOWARD NORMAL INTO MID WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 749 AM EDT FRI MAY 17 2013

VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...AS MID AND HIGH
CLOUDS DOMINATE THE DAYTIME HOURS. BASES SHOULD BE AT OR ABOVE
9000FT. CEILINGS MAY LOWER SOME TONIGHT...BUT 5000-6000FT BASES WILL
KEEP CONDITIONS AT VFR. WINDS WILL BE STEADY FROM THE EAST AT 8-12
KNOTS TODAY AND TONIGHT.


&&

.MARINE...
ISSUED AT 1121 AM EDT FRI MAY 17 2013

EXPANDED THE MENTION OF RAIN IN THE FORECAST FOR NORTHERN MARINE
ZONES.

&&

.FIRE WEATHER...
ISSUED AT 334 AM EDT FRI MAY 17 2013

CONDITIONS LOOK TO BE A SLIGHT BIT BETTER THAN THU WITH REGARD TO
FIRE DANGER...ALTHOUGH THE FIRE DANGER WILL REMAIN ELEVATED. MORE
CLOUD COVER WILL LIMIT THE AMOUNT OF HEATING AND THE MIXING DOWN OF
DRIER AIR. CONDITIONS WILL ONCE AGAIN APPROACH RED FLAG CRITERIA...
HOWEVER WE EXPECT RH/S TO REMAIN JUST SHY OF THE RED FLAG
CRITERIA....WINDS TO REMAIN JUST UNDER CRITERIA WITH A FEW GUSTS TO
NEAR CRITERIA...AND TEMPS RIGHT AROUND THE THRESHOLD OF 75 DEGREES.
WE WILL NEED TO MONITOR THE SITUATION THIS AFTERNOON.

DEW POINTS SHOULD COME UP SOME OVER THE WEEKEND AS THE FLOW BECOMES
A LITTLE MORE SOUTHERLY AND MOISTURE WILL ADVECT INTO THE AREA. THIS
SHOULD KEEP RED FLAG CRITERIA FROM BEING REACHED.

&&

.HYDROLOGY...
ISSUED AT 334 AM EDT FRI MAY 17 2013

WE WILL NOT SEE ANY HYDROLOGY ISSUES THROUGH THE WEEKEND WITH LIKELY
NO RAIN AT ALL. THE CHANCES OF ANY HYDROLOGY ISSUES MON-WED NEXT
WEEK WITH RAINFALL WITH THE SYSTEM DO NOT LOOK THAT GREAT EITHER.
THE SURFACE OF THE SOIL AROUND THE AREA HAS DRIED CONSIDERABLY...AND
RIVER/STREAM LEVELS HAVE RETURNED TO NEAR AVERAGE FLOWS. THE MODELS
ARE SHOWING RAINFALL AMOUNTS OF OVER AN INCH POSSIBLE FROM MON-WED.
THIS SHOULD NOT ALL COME AT ONCE...AND THE GROUND SHOULD SOAK IT UP
PRETTY WELL. RIVER LEVELS WILL COME UP...HOWEVER WE DO NOT EXPECT
ANY NOTABLE ISSUES AT THIS TIME.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...DUKE
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...MJS

000
FXUS63 KGRR 171353
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
953 AM EDT FRI MAY 17 2013

LATEST UPDATE...
UPDATE/MARINE

.SYNOPSIS...
ISSUED AT 334 AM EDT FRI MAY 17 2013

MORE CLOUDS WILL MOVE INTO THE AREA TODAY AS A SYSTEM TO OUR WEST
TRIES TO MOVE IN. DRY LOW LEVELS WILL KEEP RAIN CHANCES NEAR ZERO
FOR THE AREA. SOME LOW CHANCES OF RAIN WILL BE POSSIBLE TONIGHT AND
EARLY SATURDAY AS A FRONTAL SYSTEM MOVES BY JUST NORTHWEST OF THE
AREA. CONDITIONS SHOULD CLEAR OUT A BIT FOR LATER SATURDAY AND
SUNDAY WITH WARM TEMPERATURES EXPECTED. BETTER CHANCES FOR RAINFALL
WILL COME TOWARD MONDAY AND LINGER THROUGH WEDNESDAY NEXT WEEK.

&&

.UPDATE...
ISSUED AT 949 AM EDT FRI MAY 17 2013

ADDED A FEW RAIN SHOWERS TO THE FORECAST FOR LUDINGTON TO NEAR
CADILLAC. RADAR TRENDS SHOW INCREASING RETURNS AND THE OBSERVATION
OUT OF CADILLAC INDICATED THAT THE PRECIPITATION WAS REACHING THE
GROUND. AM MONITORING THE WEAKENING THUNDERSTORMS OVER IN ERN
WISCONSIN. MAY NEED TO ADD SOME PRECIPITATION TO THE MUSKEGON
FORECAST AS WELL IF THEY DO NOT WEAKEN QUICKLY ENOUGH. I DID
ADJUST TEMPERATURES DOWNWARD SLIGHTLY FOR NORTHERN ZONES DUE TO
THE CLOUDS AND PRECIPITATION.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

THE MAIN CHALLENGE IN THE SHORT TERM IS DETERMINING PCPN CHCS
THROUGH THE PERIOD. MOST OF THE PERIOD THROUGH THE WEEKEND LOOKS
DRY...HOWEVER THERE ARE A COUPLE OF PERIODS WHERE RAIN POTENTIAL HAS
TO BE ADDRESSED.

WE EXPECT THAT THE AREA WILL STAY DRY DURING THE DAY TODAY. HIGH
CLOUDS STREAMING IN FROM THE WEST ARE SHROUDING THE AREA PRETTY WELL
THIS MORNING. SOME MID CLOUD COVER IS SHOWING UP OVER WEST CENTRAL
AREAS OF THE CWFA. THERE IS SOME MOISTURE TRANSPORT/THETA E
ADVECTION TAKING PLACE IN THE MID LEVELS. THE BEST PUSH OF EACH IS
OCCURRING FURTHER WEST IN WI. IN ADDITION...THE EASTERLY FLOW IS
CONTINUING TO FEED DRIER AIR IN ACROSS THE AREA. THESE FACTORS
SHOULD KEEP THE ENTIRE AREA DRY TODAY. TEMPS WILL LIKELY BE A COUPLE
OF DEGREES COOLER TODAY WITH LESS SOLAR INSOLATION.

THE FIRST CHC OF RAIN THAT COULD OCCUR WOULD BE DURING THE PERIOD
FROM TONIGHT INTO SAT MORNING ACROSS THE N/NW COUNTIES. WE HAVE
ADDED A SLIGHT CHC OF SHOWERS TO THE N/NW COUNTIES. THE BEST MID
LEVEL THETA E ADVECTION/MOISTURE TRANSPORT CONTINUES TO BE W/NW OF
THE AREA. THERE ARE SOME SOLUTIONS SHOWING THERE COULD BE JUST
ENOUGH FORCING AND DEEP ENOUGH MOISTURE TO GENERATE ENOUGH PCPN TO
REACH THE GROUND THROUGH THE DRIER LOWER LEVELS.

BY SAT AFTERNOON...WE SEE SUFFICIENT DIGGING OF THE WRN TROUGH AND
RESULTANT BUILDING OF THE UPPER RIDGE OVER THE AREA TO PUSH THE
CLOUDS AND PCPN WELL NORTH OF THE CWFA. MORE SUNSHINE COMPARED TO
THIS AFTERNOON WILL HELP TO WORK ON THE WARMING H850 TEMPS TO AROUND
12-13C AND SUPPORT HIGHS AROUND 80. THE LOW LEVEL FLOW WILL BE
VEERING A BIT TO THE S/SE AS THE HUDSON BAY RIDGE SHIFTS EAST. THIS
WILL HELP TO START ADVECTING SOMEWHAT HIGHER DEW POINTS INTO THE
AREA. FCST SOUNDINGS SHOW THAT THE LOW LEVELS WILL STILL BE JUST A
LITTLE TOO DRY YET TO ALLOW FOR ANY POP UP DIURNAL CONVECTION ALONG
ANY BOUNDARIES.

WE WILL SEE MORE SUNSHINE ON SUN WITH TEMPS INCREASING A CATEGORY AS
TEMPS ALOFT UNDER THE RIDGE INCREASE A COUPLE OF DEGREES C. SUN
MIGHT SEE A SLIGHTLY BETTER CHC FOR A POP UP SHOWER DURING THE
AFTERNOON HOURS AS BETTER LOW LEVEL MOISTURE DOES ADVECT IN. FCST
SOUNDINGS INDICATE THAT THE MID AND UPPER LEVELS MAY BE JUST A TAD
TOO WARM YET WITH THE UPPER RIDGE OVERHEAD TO ALLOW SHOWERS TO FORM.
THE CHC IS NOT ZERO...HOWEVER IT LOOKS JUST A LITTLE TOO LOW AT THIS
TIME TO JUSTIFY ADDING IN THE CHC.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

LONG TERM PATTERN BEGINS WITH THE UPPER RIDGE OVERHEAD AND AN UPPER
LOW ACROSS THE NORTHERN PLAINS. THE RIDGE GRADUALLY SHIFTS SOUTH AND
EAST ALLOWING THE GREAT LAKES TO BECOME MORE UNDER THE INFLUENCE OF
THE UPPER LOW NEXT WEEK. THE UPPER LOW FILLS WITH TIME AND BECOMES
ABSORBED INTO A EASTERN CANADIAN UPPER TROUGH. BOTH THE GFS AND
ECMWF PAINT THIS SCENARIO.

AT THE SURFACE LOW PRESSURE WILL GRADUALLY MOVE INTO THE GREAT LAKES
STATES FROM THE WEST INTO MID WEEK. ISOLATED SHOWERS AND STORMS
APPEAR POSSIBLE SUNDAY NIGHT...WITH CHANCES RAMPING UP TO LIKELY
FROM TUESDAY INTO WEDNESDAY AS THE LOW AND A SURFACE WARM FRONT WILL
BE IN THE AREA. THE THUNDER THREAT DIMINISHES INTO WEDNESDAY NIGHT
AND THURSDAY AND HAVE SHOWERS ONLY IN THE FORECAST DURING THESE
PERIODS.

THE LONG TERM PERIOD LOOKS TO BE WET OVERALL...WITH RAINFALL IN
EXCESS OF AN INCH POSSIBLE AS THE UPPER LOW SLOWLY MOVES THROUGH THE
REGION. TEMPERATURES WILL START OUT WARM IN SOUTHERLY
FLOW...TRENDING BACK TOWARD NORMAL INTO MID WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 749 AM EDT FRI MAY 17 2013

VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...AS MID AND HIGH
CLOUDS DOMINATE THE DAYTIME HOURS. BASES SHOULD BE AT OR ABOVE
9000FT. CEILINGS MAY LOWER SOME TONIGHT...BUT 5000-6000FT BASES WILL
KEEP CONDITIONS AT VFR. WINDS WILL BE STEADY FROM THE EAST AT 8-12
KNOTS TODAY AND TONIGHT.


&&

.MARINE...
ISSUED AT 949 AM EDT FRI MAY 17 2013

OTHER THAN ADDING SOME PRECIPITATION TO THE FORECAST FOR NORTHERN
MARINE ZONES...NO OTHER CHANGES WERE MADE TO THE FORECAST WITH THE
MORNING UPDATE.

&&

.FIRE WEATHER...
ISSUED AT 334 AM EDT FRI MAY 17 2013

CONDITIONS LOOK TO BE A SLIGHT BIT BETTER THAN THU WITH REGARD TO
FIRE DANGER...ALTHOUGH THE FIRE DANGER WILL REMAIN ELEVATED. MORE
CLOUD COVER WILL LIMIT THE AMOUNT OF HEATING AND THE MIXING DOWN OF
DRIER AIR. CONDITIONS WILL ONCE AGAIN APPROACH RED FLAG CRITERIA...
HOWEVER WE EXPECT RH/S TO REMAIN JUST SHY OF THE RED FLAG
CRITERIA....WINDS TO REMAIN JUST UNDER CRITERIA WITH A FEW GUSTS TO
NEAR CRITERIA...AND TEMPS RIGHT AROUND THE THRESHOLD OF 75 DEGREES.
WE WILL NEED TO MONITOR THE SITUATION THIS AFTERNOON.

DEW POINTS SHOULD COME UP SOME OVER THE WEEKEND AS THE FLOW BECOMES
A LITTLE MORE SOUTHERLY AND MOISTURE WILL ADVECT INTO THE AREA. THIS
SHOULD KEEP RED FLAG CRITERIA FROM BEING REACHED.

&&

.HYDROLOGY...
ISSUED AT 334 AM EDT FRI MAY 17 2013

WE WILL NOT SEE ANY HYDROLOGY ISSUES THROUGH THE WEEKEND WITH LIKELY
NO RAIN AT ALL. THE CHANCES OF ANY HYDROLOGY ISSUES MON-WED NEXT
WEEK WITH RAINFALL WITH THE SYSTEM DO NOT LOOK THAT GREAT EITHER.
THE SURFACE OF THE SOIL AROUND THE AREA HAS DRIED CONSIDERABLY...AND
RIVER/STREAM LEVELS HAVE RETURNED TO NEAR AVERAGE FLOWS. THE MODELS
ARE SHOWING RAINFALL AMOUNTS OF OVER AN INCH POSSIBLE FROM MON-WED.
THIS SHOULD NOT ALL COME AT ONCE...AND THE GROUND SHOULD SOAK IT UP
PRETTY WELL. RIVER LEVELS WILL COME UP...HOWEVER WE DO NOT EXPECT
ANY NOTABLE ISSUES AT THIS TIME.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...DUKE
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...MJS

000
FXUS63 KAPX 171337
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
937 AM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT FRI MAY 17 2013

HIGH PRESSURE WILL REMAIN IN CONTROL OF NORTHERN MICHIGANS WEATHER
THROUGH TODAY...RESULTING IN DRY WEATHER UNDER PARTLY SUNNY SKIES
AND SEASONABLE TEMPERATURES. WARM AND MOIST AIR PRESSING INTO THE
MIDWEST AND GREAT LAKES WILL BRING A CHANCE FOR SHOWERS TO THE
NORTH WOODS OVER THE WEEKEND...MAINLY ON SATURDAY.

&&

.UPDATE...
ISSUED AT 936 AM EDT FRI MAY 17 2013

INCREASINGLY CHALLENGING FORECAST DEVELOPING FOR TODAY. UPSTREAM
REMNANT MCS ON LEADING EDGE OF THETA-E ADVECTION/NOSE OF LOW LEVEL
JET CONTINUES TO DRIVE EAST ACROSS SOUTHERN WISCONSIN...WITH SOME
LEADING EDGE RETURNS SPILLING INTO SOUTHWEST SECTIONS OF OUR AREA
(EVEN SOME EVIDENCE OF MID LEVEL FGEN HELPING MAINTAIN/EXPAND THESE
LEADING EDGE SHOWERS). LOW LEVELS REMAIN DRY...AND JUST HAD FIRST
REPORTS OF RAIN REACHING THE SURFACE AT CADILLAC. HAVE ADJUSTED
FORECAST A TOUCH MORE PESSIMISTICALLY SOUTH OF TRAVERSE
CITY...ALTHOUGH TRENDS SUGGEST PERHAPS NOT PESSIMISTICALLY ENOUGH.
LATEST HIGH RES HRRR SOMEWHAT DISCONCERTING...DRIVING DECAYING MCS
ACROSS THE SOUTH HALF OF THE AREA THIS AFTERNOON...PRODUCING RATHER
WIDESPREAD LIGHT SHOWERS. PERUSAL OF OTHER GUIDANCE AND MODEL
DERIVED SOUNDINGS SUGGEST OTHERWISE...WITH DEEP LOW LEVEL DRY LAYER
AND LOSS OF DYNAMICS ESSENTIALLY FULLY DECAYING THIS ACTIVITY BEFORE
IT REACHES OUR AREA. THAT SAID...RADAR RETURNS MORE THAN
OMINOUS...AND DEFINITE FUTURE CHANGES MORE THAN EXPECTED. MORE
CLOUDS/RAIN WOULD ALSO MEAN SIGNIFICANTLY COOLER TEMPERATURES ACROSS
THE SOUTH. WILL CONTINUE TO MONITOR.

UPDATE ISSUED AT 606 AM EDT FRI MAY 17 2013

FORECAST APPEARS ON TRACK FOR THE MOMENT. SUBSTANTIAL HIGH CLOUDS
FROM UPSTREAM CONVECTION HAVE OVERSPREAD MUCH OF THE CWA...
ESPECIALLY NRN LOWER MICHIGAN. SATELLITE TRENDS REVEAL ABUNDANT
HIGHER CLOUD COVER UPSTREAM THAT WILL CONTINUE TO STREAM THROUGH
THE REGION TODAY. THUS PARTLY SUNNY TO OCCASIONALLY MOSTLY CLOUDY
SKIES SHOULD WORK OUT.

OTHERWISE...QUITE A FEW LOCATIONS ARE IN THE UPPER 30S WITH A FEW
SPOTS COLDER (PLN IS 32F). WARMEST LOCATIONS ARE IN THE SW
COUNTIES (TVC/FKS/MBL...ETC). CAN PROBABLY SAFELY TRIM THOSE
COUNTIES OUT OF THE FREEZE ADVISORY EARLY.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT FRI MAY 17 2013

OVERVIEW: FAIRLY PROGRESSIVE FLOW PATTERN ACROSS THE CONUS CURRENTLY
BUT STARTING TO BECOME MORE AMPLIFIED AS TROUGHINESS DEEPENS ALONG
THE WEST COAST...AND DOWNSTREAM RIDGING BUILDS THROUGH THE PLAINS
AND INTO THE GREAT LAKES. RIDGING GRADUALLY BUILDS INTO THE GREAT
LAKES HEADING THROUGH THE WEEKEND SIGNALING WARMER DAYS AHEAD.

MEANWHILE...HIGH PRESSURE HAS NUDGED IT/S WAY DOWN OUT OF ONTARIO
AND INTO THE WESTERN GREAT LAKES. ONGOING MCS ACTIVITY TO OUR
SOUTHWEST ACROSS IOWA...BUT WILL STAY WELL AWAY FROM US AS
MOISTURE/INSTABILITY REMAINS DISPLACED WELL OFF TO OUR WEST AND SOUTH.

TODAY...HIGH PRESSURE AND ANTECEDENT DRY AIRMASS WILL CONTINUE TO
DOMINATE THE REGION WITH NO PRECIP ANTICIPATED. HOWEVER...THERE IS
QUITE A BIT OF MID AND HIGH CLOUD COVER UPSTREAM FROM ONGOING
CONVECTION AS WELL AS INCREASING WARM ADVECTION ACROSS THE PLAINS.
THUS...WILL SEE VARIOUS ROUNDS OF MID AND HIGH CLOUD SLIDING THROUGH
THE REGION...LEADING TO PARTLY CLOUDY TO OCCASIONALLY MOSTLY CLOUDY
SKIES. TEMPERATURES...A LITTLE WARMER AS COMPARED TO THURSDAY WITH
HIGHS RANGING FROM THE MID 60S TO LOWER 70S.

FIRE WEATHER CONCERNS...DRY ANTECEDENT CONDITIONS PERSIST AND EXPECT
INLAND SFC DEWPOINTS WILL DIP INTO THE LOWER 30S DURING THE
AFTERNOON LIKE THURSDAY WITH MINIMUM RH VALUES GOING BELOW 25
PERCENT. HOWEVER...TEMPS WILL LARGELY REMAIN BELOW 75 FOR MOST AREAS
AND WINDS WILL BE FAIRLY LIGHT (UNDER 10 MPH). YES IT WILL BE DRY
BUT WITHOUT DECENT WIND...WILL NOT HAVE ELEVATED FIRE DANGER
MENTIONED IN THE HWO FOR TODAY.

TONIGHT...WARM AND MOIST AIR (HIGH THETA-E) BUILDS THROUGH THE
PLAINS AND THE UPPER MIDWEST THROUGH THE COURSE OF THE NIGHT WITH
THE STRONGEST SURGE/FORCING OCCURRING ACROSS THE NRN PLAINS AND UPPER
MIDWEST WHERE ONE OR MORE CONVECTIVE SYSTEMS WILL LIKELY BE ONGOING
OR DEVELOP. HERE AT HOME...NOT SO IMPRESSED. NW-SE ORIENTED THETA-E
GRADIENT WILL BE INCHING UP THROUGH STATE THROUGH THE COURSE OF THE
NIGHT. BUT AGAIN...MUCH STRONGER LOW LEVEL FLOW AND RESULTING
FORCING (MOIST CONVERGENCE) WILL REMAIN WELL WEST-NORTHWEST OF THE
CWA WHERE MOST CONVECTIVE ACTIVITY WILL BE CONFINED. SUPPOSE ITS
PLAUSIBLE WE GET A FEW ELEVATED SHOWERS TO DEVELOP ALONG THE
ADVANCING THETA-E GRADIENT ALTHOUGH LAPSE RATES ALOFT ARE JUST NOT
THAT SUPPORTIVE OF CONVECTION. IN THE END...FOR CONTINUITY AND
COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO MAINTAIN CHANCE
POPS FOR SHOWERS OVER NW LOWER MICHIGAN OVERNIGHT BUT HAVE TRIMMED
POPS BACK TO 30 PERCENT OR LESS.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM EDT FRI MAY 17 2013

A WARMER AND PROGRESSIVELY MORE MOIST SOUTHEASTERLY FLOW WILL LEAD
TO CHANCES FOR SHOWERS THIS WEEKEND. THERE WILL BE CHANCES FOR
SHOWERS AND EVEN THUNDERSTORMS EARLY NEXT WEEK WHICH WILL BECOME
LIKELY BY THE MIDDLE OF NEXT WEEK...AS A CUTOFF UPPER TROUGH
APPROACHES FROM OUR SOUTHWEST. FINALLY...CONDITIONS MOST LIKELY  DRY
OUT BY THURSDAY AS THIS SYSTEM RETREATS TO THE SOUTHEAST. THE MAIN
LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS AND HOW MUCH IT WILL
WARM UP THIS WEEKEND INTO EARLY NEXT WEEK.

SATURDAY AND SUNDAY...MODELS ARE ONLY IN FAIR AGREEMENT ON THE
TIMING AND AMOUNT OF MOISTURE ADVECTION INTO THE REGION AS THETA-E
RIDGING APPROACHES THE FORECAST AREA BUT WEAKENS AS IT DOES SO. THIS
IS IN RESPONSE TO A DECAYING AREA OF LOW PRESSURE MOVING BY TO THE
NORTHWEST. IT IS STILL UNCERTAIN IF IT WILL MOISTEN UP ENOUGH ACROSS
NORTHERN MICHIGAN TO ACTUALLY RAIN...AS THE MAIN ACTION LOOKS TO
REMAIN TO OUR WEST. SO WILL BACK OFF ON POPS TO SLIGHT AND LOW
CHANCES FOR SHOWERS. HIGHS SATURDAY RANGING FROM THE MIDDLE 60S TO
MIDDLE 70S...WITH THE WARMER 70S TO LOWER 80S ON SUNDAY EXPECTED.
LOWS SATURDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.

MONDAY THROUGH THURSDAY...SHOWERS AND THUNDERSTORM CHANCES INCREASE
MONDAY THEN BECOME LIKELY MONDAY NIGHT INTO WEDNESDAY AS A CUTOFF
UPPER LEVEL TROUGH AND WARM FRONT APPROACH FROM THE SOUTHWEST.
EXTENDED MODELS THEN VARY ON THE TIMING OF DRYING FROM THE
NORTH...BUT WILL PENCIL THURSDAY IN AS A DRY DAY AS THIS SYSTEM IS
SHOWN TO SLOWLY RETREAT TO OUR SOUTHEAST. REMAINING WARM WITH HIGHS
IN THE 70S TO LOWER 80S MONDAY...FOLLOWED BY A SLOW COOLING TREND
WITH TEMPERATURES ENDING UP IN THE UPPER 50S TO LOWER 60S FOR HIGHS
BY THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 606 AM EDT FRI MAY 17 2013

SOLID VFR CONDITIONS THROUGH THE UPCOMING TAF FORECAST PERIOD...
BUT WITH GRADUALLY LOWERING CIGS THIS AFTERNOON AND TONIGHT. LIGHT
WINDS (UNDER 10 KNOTS) WITH WIND DIRECTIONS LAKE DOMINATED AT THE
TAF SITES.


&&

.MARINE...
ISSUED AT 352 AM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TODAY AND TONIGHT
WITH NO MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES
SATURDAY AND SATURDAY NIGHT AND A HANDFUL OF SMALL CRAFT ADVISORIES
MAY BE NEEDED. AT THAT TIME.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...MB
SYNOPSIS...AS
SHORT TERM...BA
LONG TERM...AS
AVIATION...BA
MARINE...BA

000
FXUS63 KGRR 171149
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
749 AM EDT FRI MAY 17 2013

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 334 AM EDT FRI MAY 17 2013

MORE CLOUDS WILL MOVE INTO THE AREA TODAY AS A SYSTEM TO OUR WEST
TRIES TO MOVE IN. DRY LOW LEVELS WILL KEEP RAIN CHANCES NEAR ZERO
FOR THE AREA. SOME LOW CHANCES OF RAIN WILL BE POSSIBLE TONIGHT AND
EARLY SATURDAY AS A FRONTAL SYSTEM MOVES BY JUST NORTHWEST OF THE
AREA. CONDITIONS SHOULD CLEAR OUT A BIT FOR LATER SATURDAY AND
SUNDAY WITH WARM TEMPERATURES EXPECTED. BETTER CHANCES FOR RAINFALL
WILL COME TOWARD MONDAY AND LINGER THROUGH WEDNESDAY NEXT WEEK.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

THE MAIN CHALLENGE IN THE SHORT TERM IS DETERMINING PCPN CHCS
THROUGH THE PERIOD. MOST OF THE PERIOD THROUGH THE WEEKEND LOOKS
DRY...HOWEVER THERE ARE A COUPLE OF PERIODS WHERE RAIN POTENTIAL HAS
TO BE ADDRESSED.

WE EXPECT THAT THE AREA WILL STAY DRY DURING THE DAY TODAY. HIGH
CLOUDS STREAMING IN FROM THE WEST ARE SHROUDING THE AREA PRETTY WELL
THIS MORNING. SOME MID CLOUD COVER IS SHOWING UP OVER WEST CENTRAL
AREAS OF THE CWFA. THERE IS SOME MOISTURE TRANSPORT/THETA E
ADVECTION TAKING PLACE IN THE MID LEVELS. THE BEST PUSH OF EACH IS
OCCURRING FURTHER WEST IN WI. IN ADDITION...THE EASTERLY FLOW IS
CONTINUING TO FEED DRIER AIR IN ACROSS THE AREA. THESE FACTORS
SHOULD KEEP THE ENTIRE AREA DRY TODAY. TEMPS WILL LIKELY BE A COUPLE
OF DEGREES COOLER TODAY WITH LESS SOLAR INSOLATION.

THE FIRST CHC OF RAIN THAT COULD OCCUR WOULD BE DURING THE PERIOD
FROM TONIGHT INTO SAT MORNING ACROSS THE N/NW COUNTIES. WE HAVE
ADDED A SLIGHT CHC OF SHOWERS TO THE N/NW COUNTIES. THE BEST MID
LEVEL THETA E ADVECTION/MOISTURE TRANSPORT CONTINUES TO BE W/NW OF
THE AREA. THERE ARE SOME SOLUTIONS SHOWING THERE COULD BE JUST
ENOUGH FORCING AND DEEP ENOUGH MOISTURE TO GENERATE ENOUGH PCPN TO
REACH THE GROUND THROUGH THE DRIER LOWER LEVELS.

BY SAT AFTERNOON...WE SEE SUFFICIENT DIGGING OF THE WRN TROUGH AND
RESULTANT BUILDING OF THE UPPER RIDGE OVER THE AREA TO PUSH THE
CLOUDS AND PCPN WELL NORTH OF THE CWFA. MORE SUNSHINE COMPARED TO
THIS AFTERNOON WILL HELP TO WORK ON THE WARMING H850 TEMPS TO AROUND
12-13C AND SUPPORT HIGHS AROUND 80. THE LOW LEVEL FLOW WILL BE
VEERING A BIT TO THE S/SE AS THE HUDSON BAY RIDGE SHIFTS EAST. THIS
WILL HELP TO START ADVECTING SOMEWHAT HIGHER DEW POINTS INTO THE
AREA. FCST SOUNDINGS SHOW THAT THE LOW LEVELS WILL STILL BE JUST A
LITTLE TOO DRY YET TO ALLOW FOR ANY POP UP DIURNAL CONVECTION ALONG
ANY BOUNDARIES.

WE WILL SEE MORE SUNSHINE ON SUN WITH TEMPS INCREASING A CATEGORY AS
TEMPS ALOFT UNDER THE RIDGE INCREASE A COUPLE OF DEGREES C. SUN
MIGHT SEE A SLIGHTLY BETTER CHC FOR A POP UP SHOWER DURING THE
AFTERNOON HOURS AS BETTER LOW LEVEL MOISTURE DOES ADVECT IN. FCST
SOUNDINGS INDICATE THAT THE MID AND UPPER LEVELS MAY BE JUST A TAD
TOO WARM YET WITH THE UPPER RIDGE OVERHEAD TO ALLOW SHOWERS TO FORM.
THE CHC IS NOT ZERO...HOWEVER IT LOOKS JUST A LITTLE TOO LOW AT THIS
TIME TO JUSTIFY ADDING IN THE CHC.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 334 AM EDT FRI MAY 17 2013

LONG TERM PATTERN BEGINS WITH THE UPPER RIDGE OVERHEAD AND AN UPPER
LOW ACROSS THE NORTHERN PLAINS. THE RIDGE GRADUALLY SHIFTS SOUTH AND
EAST ALLOWING THE GREAT LAKES TO BECOME MORE UNDER THE INFLUENCE OF
THE UPPER LOW NEXT WEEK. THE UPPER LOW FILLS WITH TIME AND BECOMES
ABSORBED INTO A EASTERN CANADIAN UPPER TROUGH. BOTH THE GFS AND
ECMWF PAINT THIS SCENARIO.

AT THE SURFACE LOW PRESSURE WILL GRADUALLY MOVE INTO THE GREAT LAKES
STATES FROM THE WEST INTO MID WEEK. ISOLATED SHOWERS AND STORMS
APPEAR POSSIBLE SUNDAY NIGHT...WITH CHANCES RAMPING UP TO LIKELY
FROM TUESDAY INTO WEDNESDAY AS THE LOW AND A SURFACE WARM FRONT WILL
BE IN THE AREA. THE THUNDER THREAT DIMINISHES INTO WEDNESDAY NIGHT
AND THURSDAY AND HAVE SHOWERS ONLY IN THE FORECAST DURING THESE
PERIODS.

THE LONG TERM PERIOD LOOKS TO BE WET OVERALL...WITH RAINFALL IN
EXCESS OF AN INCH POSSIBLE AS THE UPPER LOW SLOWLY MOVES THROUGH THE
REGION. TEMPERATURES WILL START OUT WARM IN SOUTHERLY
FLOW...TRENDING BACK TOWARD NORMAL INTO MID WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 749 AM EDT FRI MAY 17 2013

VFR CONDITIONS ARE EXPECTED THE NEXT 24 HOURS...AS MID AND HIGH
CLOUDS DOMINATE THE DAYTIME HOURS. BASES SHOULD BE AT OR ABOVE
9000FT. CEILINGS MAY LOWER SOME TONIGHT...BUT 5000-6000FT BASES WILL
KEEP CONDITIONS AT VFR. WINDS WILL BE STEADY FROM THE EAST AT 8-12
KNOTS TODAY AND TONIGHT.

&&

.MARINE...
ISSUED AT 334 AM EDT FRI MAY 17 2013

WE DO NOT EXPECT ANY HEADLINES AT THIS TIME FOR THE WEEKEND. WINDS
WILL COME UP A LITTLE BIT...WITH GENERAL 10 TO 15 KNOTS EXPECTED.
SOME PERIODS OF WIND OF UP TO 20 KNOTS MIGHT BE POSSIBLE. THE FLOW
WILL START OFF OFFSHORE AND EVENTUALLY SHIFT TO THE SOUTH BY LATER
IN THE WEEKEND. WAVES WILL REMAIN UNDER 4 FEET DUE TO THE MAGNITUDE
OF THE WIND AND STABLE CONDITIONS OVER THE LAKE.


&&

.FIRE WEATHER...
ISSUED AT 334 AM EDT FRI MAY 17 2013

CONDITIONS LOOK TO BE A SLIGHT BIT BETTER THAN THU WITH REGARD TO
FIRE DANGER...ALTHOUGH THE FIRE DANGER WILL REMAIN ELEVATED. MORE
CLOUD COVER WILL LIMIT THE AMOUNT OF HEATING AND THE MIXING DOWN OF
DRIER AIR. CONDITIONS WILL ONCE AGAIN APPROACH RED FLAG CRITERIA...
HOWEVER WE EXPECT RH/S TO REMAIN JUST SHY OF THE RED FLAG
CRITERIA....WINDS TO REMAIN JUST UNDER CRITERIA WITH A FEW GUSTS TO
NEAR CRITERIA...AND TEMPS RIGHT AROUND THE THRESHOLD OF 75 DEGREES.
WE WILL NEED TO MONITOR THE SITUATION THIS AFTERNOON.

DEW POINTS SHOULD COME UP SOME OVER THE WEEKEND AS THE FLOW BECOMES
A LITTLE MORE SOUTHERLY AND MOISTURE WILL ADVECT INTO THE AREA. THIS
SHOULD KEEP RED FLAG CRITERIA FROM BEING REACHED.

&&

.HYDROLOGY...
ISSUED AT 334 AM EDT FRI MAY 17 2013

WE WILL NOT SEE ANY HYDROLOGY ISSUES THROUGH THE WEEKEND WITH LIKELY
NO RAIN AT ALL. THE CHANCES OF ANY HYDROLOGY ISSUES MON-WED NEXT
WEEK WITH RAINFALL WITH THE SYSTEM DO NOT LOOK THAT GREAT EITHER.
THE SURFACE OF THE SOIL AROUND THE AREA HAS DRIED CONSIDERABLY...AND
RIVER/STREAM LEVELS HAVE RETURNED TO NEAR AVERAGE FLOWS. THE MODELS
ARE SHOWING RAINFALL AMOUNTS OF OVER AN INCH POSSIBLE FROM MON-WED.
THIS SHOULD NOT ALL COME AT ONCE...AND THE GROUND SHOULD SOAK IT UP
PRETTY WELL. RIVER LEVELS WILL COME UP...HOWEVER WE DO NOT EXPECT
ANY NOTABLE ISSUES AT THIS TIME.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...DUKE
AVIATION...DUKE
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...NJJ

000
FXUS63 KMQT 171130
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
730 AM EDT FRI MAY 17 2013

.UPDATE...
ISSUED AT 633 AM EDT FRI MAY 17 2013

BAND OF ISOLD SHRA/SPRINKLES EDGING OUT OF MINNESOTA ONTO WESTERN LK
SUPERIOR. H7 FGEN/MOISTURE BAND SUPPORTING THESE COULD CLIP KEWEENAW
SO HAVE INCLUDED SOME SPRINKLES FOR THE MORNING. INCREASED SKY COVER
FOR ALL BUT FAR EAST AS 12-15KFT DECK OF CLOUDS HAS SOLIDIFIED OVER
LAST COUPLE HOURS. WITH MORE CLOUD COVER...TEMPS HAVE BECOME STEADY
OR EVEN SLOWLY RISING. ADJUSTED TEMPS NEXT FEW HOURS. THINNING OUT OF
CLOUDS OVER NORTH STILL POSSIBLE BY AFTN WITH LOSS OF DIVERGENCE
ALOFT. FARTHER SOUTH THE SHOWERS LIFTING NORTH THROUGH WI...AS FAR
NORTH AS KAUW...STILL ON TRACK TO AFFECT VCNTY OF MEMOMINEE AFTER
17Z.
&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT FRI MAY 17 2013

IN CONFLUENT FLOW PATTERN ALOFT EXPECT HIGH PRESSURE TO EXPAND FROM
NORTHERN ONTARIO ACROSS GREAT LAKES TODAY. LIGHT WINDS OVER FAR EAST
ALONG THE RIDGE AXIS AND CLEARER SKIES HAVE ALLOWED TEMPS TO FALL
BLO 30 AT A FEW OF THE FIRE WX RAWS SITES. WARM FRONT STAYS WELL TO
SOUTHWEST OF UPR MICHIGAN TODAY...CURRENTLY FROM CENTRAL PLAINS INTO
NORTHERN OHIO VALLEY...ONLY ADVANCING INTO SOUTHERN MINNESOTA AND
SOUTHERN WISCONSIN BY THIS EVENING. A LOT OF MID CLOUDS OVER THE
UPPER LAKES REGION THIS MORNING. REGIONAL RADAR LOOP SHOWS MULTIPLE
RIBBONS OF SHRA ACROSS NORTHERN MINNESOTA AND ALSO AS FAR NORTH AS
CENTRAL WISCONSIN. BOTH AREAS OF SHOWERS ARE SUPPORTED BY MID-LEVEL
FRONTOGENESIS AND H85-H7 MOISTURE ADVECTION. MORE ORGANIZED CLUSTER
OF SHRA AND NMRS TSRA OCCURRING OVER NORTHERN IA INTO FAR SOUTHERN
MINNESOTA ALONG H85 WARM FRONT/H95 MOISTURE CONVERGENCE AND ON EDGE
OF 1-6KM MUCAPE GRADIENT.

PRIMARY QUESTION IS RAIN POTENTIAL/COVERAGE THROUGH TONIGHT. TO SUM
UP HAVE WENT WITH DRIER FCST FARTHER NORTH INTO UPR MICHIGAN
COMPARED TO WHAT MANY MODELS SHOW. THINKING THAT MAJORITY OF MODELS
ARE OVERDONE WITH PRECIP GIVEN BUILDING SFC-H85 HIGH PRESSURE RIDGE
FROM NORTHERN ONTARIO INTO THE LOWER GREAT LAKES AND LACK OF STRONG
MOISTURE ADVECTION AS FAR NORTH AS UPR MICHIGAN. SHRA OVR NORTHERN
MINNESOTA EXPECTED TO DISSIPATE AS RIGHT ENTRANCE REGION OF JET OVER
ONTARIO FADES THROUGH 15Z. ISLE ROYALE COULD STILL GET CLIPPED WITH
ISOLD SHRA...REST OF WESTERN CWA SHOULD STAY DRY. MEANWHILE...H7
MOISTURE TRANSPORT MARKING EDGE OF SHRA OVER CNTRL WISCONSIN PRETTY
WELL RIGHT NOW. MOISTURE ADVECTION AT H7 AND H8-H7 FRONTOGENESIS IS
FORECAST TO IMPACT FAR SCNTRL CWA BY LATE MORNING AND REST OF THE
DAY. HAVE BROUGHT LOW CHANCE POPS INTO MENOMINEE COUNTY...BUT SHOULD
BE SHARP CUTOFF FARTHER NORTH FOR PRECIP GIVEN DOWNWARD MOTION ON
DECENDING BRANCH OF THE MID-LEVEL FRONTOGENESIS. NAM/GEM-REGIONAL
PROBABLY TOO DRY TODAY OVER THE SOUTHERN CWA...BUT SEEM BETTER FIT
COMPARED TO GFS/ECMWF. SHOULD NOTE THAT EVEN THESE MODELS HAVE
TRENDED FARTHER SOUTH WITH AXIS OF QPF COMPARED TO MODEL RUNS FROM
THURSDAY.

ELSEWHERE...SCT-BKN MID CLOUDS SHOULD BE THE STORY ALONG WITH LGT
EASTERLY SFC WINDS WITH ORIGIN OUT OF SFC HIGH AND WELL TO NORTH OF
THE SFC WARM FRONT. THINNING OF MID CLOUDS OVERHEAD MAY OCCUR AS
RIGHT ENTRANCE REGION FORCING FROM JET OVER ONTARIO DIMINISHES.
TEMPS SHOULD HAVE NON-UNIFORM GRADIENTS DUE TO CLOUDS AND SFC WIND
TRAJECTORIES. WARMEST READINGS AROUND 70 DEGREES IN THE FAR EAST.
COOLEST READINGS IN 50S ALONG LK SUPERIOR WITH PREVAILING ONSHORE
FLOW. MAY ALSO SEE COOLER POCKET OF TEMPS SET UP ALONG WI BORDER DUE
TO THICKER CLOUD COVER AND POTENTIAL PRECIP. UNLIKE LAST FEW
DAYS...H9-H85 LIMITED DRY AIR IN THE H9-H85 LAYER SHOULD PROHIBIT
DEEP MIXING AND VERY LOW HUMIDITIES.

TONIGHT...LARGE SCALE FORCING CHANGES START TO INCREASE CHANCES FOR
PRECIP TO MAKE IT INTO AT LEAST MORE OF UPR MICHIGAN. UPPER LEVEL
TROUGH MOVES INTO NORTHERN ROCKIES WITH SFC-H85 LOWS BECOMING MORE
ORGANIZED OVER NORTHERN PLAINS. WINDS BECOME MORE SOUTHERLY OVER
UPPER MISSISSIPPI RIVER VALLEY IN RESPONSE. H85 BAROCLINIC ZONE
LIFTS TOWARD WESTERN LK SUPERIOR AND NORTHERN WISCONSIN THROUGH THE
NIGHT. ISENTROPIC ASCENT ALONG THE BOUNDARY SUPPORTS CHANCES OF SHRA
INCREASING. SHARPEST MOISTURE TRANSPORT INTO THE H85 BOUNDARY IS
OVER NORTHERN MINNESOTA AND INTO WESTERN LK SUPERIOR...WITH A
TAPERING OFF FARTHER EAST. NOT MUCH H7 MOISTURE ADVECTION FARTHER
EAST EITHER. REALLY PREFER THE GEM-REGIONAL/NAM/NCEP WRF IDEA FOR
CONVECTION TONIGHT...FAVORING MAJORITY OF SHRA/TSRA OVER NORTHERN
MINNESOTA INTO SOUTHWEST UPR MICHIGAN. EDGE OF CAPE GRADIENT ALSO
SUPPORTS BETTER TSRA POTENTIAL INTO SW UPR MICHIGAN FROM LATE
EVENING ONWARD. BY LATE TONIGHT...MAJORITY OF MODELS SHOVE THE
CONVECTION...OR AT LEAST REMNANTS OF IT...INTO CNTRL UPR MICHIGAN.
SUPPOSE THIS MAY OCCUR DO TO LEAD SHORTWAVE PRESSING ACROSS NORTHERN
MINNESOTA AND H7 MOISTURE TRANSPORT VECTORS TURNING MORE WEST TO
EAST. NOT SOLD ON A LOT OF PRECIP MAKING IT WELL TO EAST OF GRADIENT
OF INSTABILITY ALOFT...SO JUST USED SLIGHT CHANCE POPS OTHER THAN
OVER FAR WESTERN CWA. MINS TONIGHT HELD UP BY THICKENING CLOUDS AND
PRECIP. TEMPS OVER INTERIOR EAST MAY DROP INTO 30S...BUT NOT AS COOL
AS EARLY THIS MORNING. 40S TO AROUND 50 FOR MINS EVERYWHERE ELSE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 446 AM EDT FRI MAY 17 2013

NAM SHOWS A 500 MB RIDGE OVER THE UPPER GREAT LAKES 12Z SAT WITH
TROUGHING IN THE ROCKY MOUNTAINS. THE RIDGE REMAINS 12Z SUN WITH A
SHORTWAVE ON THE WESTERN SIDE IN THE DAKOTAS. TROUGHING THEN MOVES
IN THE NORTHERN PLAINS WITH A CLOSED LOW 12Z MON. NAM SHOWS SOME
DEEPER MOISTURE AND Q-VECTOR CONVERGENCE REMAINING OVER THE AREA 12Z
SAT ONWARD.

DID MAKE A MAJOR CHANGE TO THE GOING FORECAST AND WENT DRIER OVER
THE EASTERN HALF OF THE CWA THROUGH SUN NIGHT. AM FINDING IT HARD TO
BELIEVE WITH THE SLOW MOVEMENT OF THE SYSTEM TO THE WEST...BUILDING
UPPER RIDGE TO THE EAST AND A SFC HIGH PRESSURE SYSTEM BRINGING IN
DRY EAST TO SOUTHEAST FLOW...THAT PCPN WOULD BE AS WIDESPREAD AS IT
IS IN THE ECMWF...NAM AND GFS MODELS AND THINK THEY ARE ALL OVERDONE
WITH HIGHER SFC DEW POINTS BEING OVERFORECASTED WHICH HAS BEEN THE
CASE FOR THE PAST SEVERAL WEEKS. WITH HIGHER DEW POINTS BEING
FORECASTED THAN WHAT HAS OCCURRED...THIS WOULD CAUSE MORE WIDESPREAD
QPF THAN WHAT IS ACTUALLY OCCURRING DUE TO CONVECTIVE PARAMETERS
BEING ACTIVATED IN THE MODELS. WITH THIS IN MIND...WILL GO WITH A
DRIER SCENARIO AND CUT POPS BACK WITH CHANCE POPS OVER THE WEST ONLY
THROUGH SUNDAY NIGHT. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO
THE GOING FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER THE
NORTHERN PLAINS 12Z MON WITH A RIDGE OVER THE EASTERN U.S. AND
TROUGHING ACROSS THE PLAINS. PATTERN CHANGES VERY LITTLE FOR 12Z TUE
WITH A SLIGHT EASTWARD MOVEMENT 12Z WED INTO THE UPPER MISSISSIPPI
RIVER VALLEY. THIS LOW AND TROUGH MOVE INTO THE UPPER GREAT LAKES
12Z THU. ONE THING WITH THIS PATTERN IS IT WILL BE SLOW TO PROGRESS
EASTWARD. LOOKS LIKE A DECENT CHANCE FOR WIDESPREAD RAIN STARTING
MON AND LASTING INTO WED AS THE TROUGH KICKS OUT. ON THU...DRIER AIR
STARTS TO WORK IN AS A COLD FRONT HEADS SOUTH WED NIGHT INTO THU AND
POPS SHOULD BE LOWER BY THEN. SHOULD ALSO BE A COOLING TREND THIS
FORECAST PERIOD WITH TEMPERATURES COOLING TO BELOW NORMAL STARTING
TUE ONWARD.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 728 AM EDT FRI MAY 17 2013

MID-HI CLDS WL PERSIST THROUGH TONIGHT WITH CONDITIONS STAYING VFR
DUE TO DRY E WIND OUT OF HUDSON BAY HI PRES. AS THE HIGH RETREATS
SOME IT IS POSSIBLE THAT -SHRA MAY IMPACT IWD THIS EVNG. BETTER
CHANCE FOR SHOWERS AND EVEN POSSIBLE TSRA AT IWD WOULD BE VERY LATE
TONIGHT AS MID-LEVEL WARM FRONT AND INCREASING INSTABILITY MOVE INTO
WESTERN UPPER MICHIGAN. MAY SEE -SHRA SNEAK INTO CMX LATE TONIGHT AS
WELL BUT SAW SHOULD STAY DRY UNTIL AFTER DAYBREAK SATURDAY.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...JLA
SHORT TERM...JLA
LONG TERM...07
AVIATION...JLA
MARINE...07

000
FXUS63 KDTX 171055
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
655 AM EDT FRI MAY 17 2013


.AVIATION...

//DISCUSSION...

VFR CONDITIONS WILL PERSIST THROUGH THE TAF FORECAST. HIGH PRESSURE
TO THE NORTH WILL PRODUCE LIGHT EASTERLY WINDS THROUGH TONIGHT. HIGH
CLOUDS WILL STREAM INTO THE AREA FROM A DISTURBANCE OVER THE UPPER
MIDWEST...GRADUALLY THICKENING AND LOWERING INTO TONIGHT. DRY AIR IN
THE LOW LEVELS WILL PREVENT ANY LOW CLOUDS FROM FORMING UNTIL LATE
FRIDAY NIGHT WHEN CIGS WILL NEAR 5KFT.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE ON CEILING REACHING 5000 FEET TOWARD SUNRISE
SATURDAY.

&&

.PREV DISCUSSION...ISSUED 345 AM EDT FRI MAY 17 2013

SHORT TERM...TODAY AND TONIGHT

QUIET DAY IN STORE AS WE REMAIN UNDER THE SOUTHERN PERIPHERY OF
CANADIAN HIGH PRESSURE AT THE SFC WITH MID LEVEL HEIGHTS BUILDING
THROUGH THE DAY. LOOKING ALOFT...THERE ARE TWO DISTURBANCES TRYING
TO MOVE INTO THE GREAT LAKES. THE FIRST IS A CLOSED MID LEVEL LOW
DRIFTING THROUGH THE CENTRAL CONUS WITH A SLIGHT NE TRAJECTORY
TOWARD THE OHIO VALLEY. THE SECOND IS A SHORTWAVE ROUNDING THE APEX
OF THE MID LEVEL RIDGE OVER IA/MN/WI. MOST MODELS KEEP THE FIRST TO
OUR SOUTH AND TAKE THE LATTER ON A NE TRACK THROUGH NORTHERN MI.
MANY MODELS...KEEP SE MI DRY THROUGH TONIGHT BUT THE NAM/GFS STILL
HANG ONTO A SOME PRECIP AFTER MIDNIGHT TONIGHT. WITH A CONSTANT FEED
OF DRY AIR IN THE LOW LEVELS WITH THE NE FLOW FROM THE SFC
HIGH...BOTH SYSTEM WILL HAVE A TOUGH TIME GETTING ANY PRECIP TO HIT
THE GROUND. THERE IS A BAND OF ELEVATED FGEN NEAR THE 700MB THETA E
GRADIENT WHICH HAS BEEN PRODUCING SHOWERS TO OUR WEST AND WHICH THE
TAIL END WILL SWEEP NORTHWARD THROUGH THE SAGINAW VALLEY. THIS IS
ENOUGH TO KEEP SOME MENTION OF SHOWERS WHILE GIVING THE DAY CREW A
CHANCE TO LOOK AT HIRES MODELS TODAY AND GET A BETTER HANDLE OF
THINGS. SHIFTED THE INHERITED SLIGHT CHANCE NORTH ACROSS THE SAGINAW
VALLEY AND THUMB AS THIS REGION STAND THE BEST CHANCE OF SATURATING
LATE TONIGHT. THE POSITIONING OF THE SFC RIDGE WILL LEAD TO EASTERLY
WINDS THROUGH TONIGHT WHICH WILL KNOCK TEMPS DOWN A BIT FROM THE
LAST FEW DAYS...EVEN MORE FOR LOCATIONS CLOSE TO THE LAKE HURON
SHORELINE. ADDITIONALLY...THE MID AND HIGH CLOUDS STREAMING INTO THE
REGION FROM THE MIDWEST SHORTWAVE WILL HELP KEEP INSOLATION FROM
MAXIMIZING.

LONG TERM...SATURDAY THROUGH THURSDAY

LONGWAVE RIDGE WILL AMPLIFY DURING THE WEEKEND AND KEEP THE WEATHER
RELATIVELY QUIET ACROSS THE CENTRAL GREAT LAKES. ALTHOUGH THERE IS
AN OUTSIDE CHANCE OF AN ISOLATED SHOWER...CONDITIONS ARE EXPECTED TO
BE DRY AND STABLE. EASTERLY SURFACE WINDS AND ABUNDANT MID TO HIGH
LEVEL CLOUDS UNDERNEATH THE RIDGE WILL KEEP TEMPERATURES IN THE 70S
ON SATURDAY. WINDS WILL TURN SOUTHERLY ON SUNDAY AS THE SURFACE
RIDGE HEADS OFF TO THE EAST WITH HIGH TEMPERATURES TOPPING OUT
AROUND 80 DEGREES SUNDAY AFTERNOON.

A LONGWAVE TROUGH...CURRENTLY SHOWN ON WATER VAPOR IMAGERY MAKING
LANDFALL ON THE CALIFORNIA COAST...WILL CONTROL THE WEATHER FOR MUCH
OF NEXT WEEK. THIS LONGWAVE TROUGH IS FORECAST TO MOVE EAST DURING
THE WEEKEND...EMERGING EAST OF THE ROCKIES ON MONDAY AND CLOSING OFF
ACROSS THE NORTHERN PLAINS. ALTHOUGH THERE IS UNCERTAINTY REGARDING
THE PLACEMENT OF THE AFOREMENTIONED LOW...THERE SEEMS TO BE A
CONSENSUS IN GENERATING QUITE A BIT OF SHOWERS AND THUNDERSTORMS AS
A WARM STABLE ATMOSPHERE SETTLES OVER THE CENTRAL GREAT LAKES DURING
THE MONDAY THROUGH WEDNESDAY TIME FRAME. DURING THIS TIME FRAME
MUCAPE VALUES RISE TO 1000 TO 2000 J/KG...INCREASING THE THREAT FOR
ORGANIZED THUNDERSTORM ACTIVITY. HODOGRAPHS ARE RATHER UNIMPRESSIVE
ON MONDAY WITH A NEARLY UNIDIRECTIONAL SOUNDING. THERE ARE BETTER
HODOGRAPHS TUESDAY AND WEDNESDAY AS THE LOW ITSELF TRACKS THROUGH
THE REGION. HOWEVER WITH THE LOW TRACK BEING UNCERTAIN THE THREAT
FOR SEVERE THUNDERSTORMS IS UNCERTAIN GIVEN THE SHEAR VALUES ARE
VASTLY DIFFERENT DEPENDING ON THE TRACK OF THE LOW. ALTHOUGH THE
SITUATION BEARS CLOSE ATTENTION...THERE IS NOT ENOUGH CONFIDENCE
EITHER WAY REGARDING SEVERE POTENTIAL NEXT WEEK.

TEMPERATURES TAKE A NOTABLE TUMBLE BEHIND THE DEPARTING LOW ON
THURSDAY AS 850 MB TEMPERATURES FALL BACK INTO THE SINGLE DIGITS
ABOVE ZERO. THIS WOULD BRING HIGH TEMPERATURES BACK DOWN BELOW
NORMAL LATE NEXT WEEK WITH HIGH TEMPERATURES IN THE 60S.

MARINE...

THE SOUTHERN PERIPHERY OF A CANADIAN HIGH PRESSURE SYSTEM WILL
PRODUCE LIGHT NORTHEASTERLY WINDS OVER THE GREAT LAKES TODAY. WINDS
WILL VEER MORE EASTERLY ON SATURDAY AND SOUTHEASTERLY SUNDAY BUT
WILL REMAIN LIGHT. THIS WILL LEAD TO FAVORABLE MARINE CONDITIONS
THROUGH THE WEEKEND AS THE HIGH SLOWLY WORKS ACROSS THE REGION.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....DRK
SHORT TERM...DRK
LONG TERM....KURIMSKI
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).

000
FXUS63 KMQT 171037
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
637 AM EDT FRI MAY 17 2013

.UPDATE...
ISSUED AT 633 AM EDT FRI MAY 17 2013

BAND OF ISOLD SHRA/SPRINKLES EDGING OUT OF MINNESOTA ONTO WESTERN LK
SUPERIOR. H7 FGEN/MOISTURE BAND SUPPORTING THESE COULD CLIP KEWEENAW
SO HAVE INCLUDED SOME SPRINKLES FOR THE MORNING. INCREASED SKY COVER
FOR ALL BUT FAR EAST AS 12-15KFT DECK OF CLOUDS HAS SOLIDIFIED OVER
LAST COUPLE HOURS. WITH MORE CLOUD COVER...TEMPS HAVE BECOME STEADY
OR EVEN SLOWLY RISING. ADJUSTED TEMPS NEXT FEW HOURS. THINNING OUT OF
CLOUDS OVER NORTH STILL POSSIBLE BY AFTN WITH LOSS OF DIVERGENCE
ALOFT. FARTHER SOUTH THE SHOWERS LIFTING NORTH THROUGH WI...AS FAR
NORTH AS KAUW...STILL ON TRACK TO AFFECT VCNTY OF MEMOMINEE AFTER
17Z.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT FRI MAY 17 2013

IN CONFLUENT FLOW PATTERN ALOFT EXPECT HIGH PRESSURE TO EXPAND FROM
NORTHERN ONTARIO ACROSS GREAT LAKES TODAY. LIGHT WINDS OVER FAR EAST
ALONG THE RIDGE AXIS AND CLEARER SKIES HAVE ALLOWED TEMPS TO FALL
BLO 30 AT A FEW OF THE FIRE WX RAWS SITES. WARM FRONT STAYS WELL TO
SOUTHWEST OF UPR MICHIGAN TODAY...CURRENTLY FROM CENTRAL PLAINS INTO
NORTHERN OHIO VALLEY...ONLY ADVANCING INTO SOUTHERN MINNESOTA AND
SOUTHERN WISCONSIN BY THIS EVENING. A LOT OF MID CLOUDS OVER THE
UPPER LAKES REGION THIS MORNING. REGIONAL RADAR LOOP SHOWS MULTIPLE
RIBBONS OF SHRA ACROSS NORTHERN MINNESOTA AND ALSO AS FAR NORTH AS
CENTRAL WISCONSIN. BOTH AREAS OF SHOWERS ARE SUPPORTED BY MID-LEVEL
FRONTOGENESIS AND H85-H7 MOISTURE ADVECTION. MORE ORGANIZED CLUSTER
OF SHRA AND NMRS TSRA OCCURRING OVER NORTHERN IA INTO FAR SOUTHERN
MINNESOTA ALONG H85 WARM FRONT/H95 MOISTURE CONVERGENCE AND ON EDGE
OF 1-6KM MUCAPE GRADIENT.

PRIMARY QUESTION IS RAIN POTENTIAL/COVERAGE THROUGH TONIGHT. TO SUM
UP HAVE WENT WITH DRIER FCST FARTHER NORTH INTO UPR MICHIGAN
COMPARED TO WHAT MANY MODELS SHOW. THINKING THAT MAJORITY OF MODELS
ARE OVERDONE WITH PRECIP GIVEN BUILDING SFC-H85 HIGH PRESSURE RIDGE
FROM NORTHERN ONTARIO INTO THE LOWER GREAT LAKES AND LACK OF STRONG
MOISTURE ADVECTION AS FAR NORTH AS UPR MICHIGAN. SHRA OVR NORTHERN
MINNESOTA EXPECTED TO DISSIPATE AS RIGHT ENTRANCE REGION OF JET OVER
ONTARIO FADES THROUGH 15Z. ISLE ROYALE COULD STILL GET CLIPPED WITH
ISOLD SHRA...REST OF WESTERN CWA SHOULD STAY DRY. MEANWHILE...H7
MOISTURE TRANSPORT MARKING EDGE OF SHRA OVER CNTRL WISCONSIN PRETTY
WELL RIGHT NOW. MOISTURE ADVECTION AT H7 AND H8-H7 FRONTOGENESIS IS
FORECAST TO IMPACT FAR SCNTRL CWA BY LATE MORNING AND REST OF THE
DAY. HAVE BROUGHT LOW CHANCE POPS INTO MENOMINEE COUNTY...BUT SHOULD
BE SHARP CUTOFF FARTHER NORTH FOR PRECIP GIVEN DOWNWARD MOTION ON
DECENDING BRANCH OF THE MID-LEVEL FRONTOGENESIS. NAM/GEM-REGIONAL
PROBABLY TOO DRY TODAY OVER THE SOUTHERN CWA...BUT SEEM BETTER FIT
COMPARED TO GFS/ECMWF. SHOULD NOTE THAT EVEN THESE MODELS HAVE
TRENDED FARTHER SOUTH WITH AXIS OF QPF COMPARED TO MODEL RUNS FROM
THURSDAY.

ELSEWHERE...SCT-BKN MID CLOUDS SHOULD BE THE STORY ALONG WITH LGT
EASTERLY SFC WINDS WITH ORIGIN OUT OF SFC HIGH AND WELL TO NORTH OF
THE SFC WARM FRONT. THINNING OF MID CLOUDS OVERHEAD MAY OCCUR AS
RIGHT ENTRANCE REGION FORCING FROM JET OVER ONTARIO DIMINISHES.
TEMPS SHOULD HAVE NON-UNIFORM GRADIENTS DUE TO CLOUDS AND SFC WIND
TRAJECTORIES. WARMEST READINGS AROUND 70 DEGREES IN THE FAR EAST.
COOLEST READINGS IN 50S ALONG LK SUPERIOR WITH PREVAILING ONSHORE
FLOW. MAY ALSO SEE COOLER POCKET OF TEMPS SET UP ALONG WI BORDER DUE
TO THICKER CLOUD COVER AND POTENTIAL PRECIP. UNLIKE LAST FEW
DAYS...H9-H85 LIMITED DRY AIR IN THE H9-H85 LAYER SHOULD PROHIBIT
DEEP MIXING AND VERY LOW HUMIDITIES.

TONIGHT...LARGE SCALE FORCING CHANGES START TO INCREASE CHANCES FOR
PRECIP TO MAKE IT INTO AT LEAST MORE OF UPR MICHIGAN. UPPER LEVEL
TROUGH MOVES INTO NORTHERN ROCKIES WITH SFC-H85 LOWS BECOMING MORE
ORGANIZED OVER NORTHERN PLAINS. WINDS BECOME MORE SOUTHERLY OVER
UPPER MISSISSIPPI RIVER VALLEY IN RESPONSE. H85 BAROCLINIC ZONE
LIFTS TOWARD WESTERN LK SUPERIOR AND NORTHERN WISCONSIN THROUGH THE
NIGHT. ISENTROPIC ASCENT ALONG THE BOUNDARY SUPPORTS CHANCES OF SHRA
INCREASING. SHARPEST MOISTURE TRANSPORT INTO THE H85 BOUNDARY IS
OVER NORTHERN MINNESOTA AND INTO WESTERN LK SUPERIOR...WITH A
TAPERING OFF FARTHER EAST. NOT MUCH H7 MOISTURE ADVECTION FARTHER
EAST EITHER. REALLY PREFER THE GEM-REGIONAL/NAM/NCEP WRF IDEA FOR
CONVECTION TONIGHT...FAVORING MAJORITY OF SHRA/TSRA OVER NORTHERN
MINNESOTA INTO SOUTHWEST UPR MICHIGAN. EDGE OF CAPE GRADIENT ALSO
SUPPORTS BETTER TSRA POTENTIAL INTO SW UPR MICHIGAN FROM LATE
EVENING ONWARD. BY LATE TONIGHT...MAJORITY OF MODELS SHOVE THE
CONVECTION...OR AT LEAST REMNANTS OF IT...INTO CNTRL UPR MICHIGAN.
SUPPOSE THIS MAY OCCUR DO TO LEAD SHORTWAVE PRESSING ACROSS NORTHERN
MINNESOTA AND H7 MOISTURE TRANSPORT VECTORS TURNING MORE WEST TO
EAST. NOT SOLD ON A LOT OF PRECIP MAKING IT WELL TO EAST OF GRADIENT
OF INSTABILITY ALOFT...SO JUST USED SLIGHT CHANCE POPS OTHER THAN
OVER FAR WESTERN CWA. MINS TONIGHT HELD UP BY THICKENING CLOUDS AND
PRECIP. TEMPS OVER INTERIOR EAST MAY DROP INTO 30S...BUT NOT AS COOL
AS EARLY THIS MORNING. 40S TO AROUND 50 FOR MINS EVERYWHERE ELSE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 446 AM EDT FRI MAY 17 2013

NAM SHOWS A 500 MB RIDGE OVER THE UPPER GREAT LAKES 12Z SAT WITH
TROUGHING IN THE ROCKY MOUNTAINS. THE RIDGE REMAINS 12Z SUN WITH A
SHORTWAVE ON THE WESTERN SIDE IN THE DAKOTAS. TROUGHING THEN MOVES
IN THE NORTHERN PLAINS WITH A CLOSED LOW 12Z MON. NAM SHOWS SOME
DEEPER MOISTURE AND Q-VECTOR CONVERGENCE REMAINING OVER THE AREA 12Z
SAT ONWARD.

DID MAKE A MAJOR CHANGE TO THE GOING FORECAST AND WENT DRIER OVER
THE EASTERN HALF OF THE CWA THROUGH SUN NIGHT. AM FINDING IT HARD TO
BELIEVE WITH THE SLOW MOVEMENT OF THE SYSTEM TO THE WEST...BUILDING
UPPER RIDGE TO THE EAST AND A SFC HIGH PRESSURE SYSTEM BRINGING IN
DRY EAST TO SOUTHEAST FLOW...THAT PCPN WOULD BE AS WIDESPREAD AS IT
IS IN THE ECMWF...NAM AND GFS MODELS AND THINK THEY ARE ALL OVERDONE
WITH HIGHER SFC DEW POINTS BEING OVERFORECASTED WHICH HAS BEEN THE
CASE FOR THE PAST SEVERAL WEEKS. WITH HIGHER DEW POINTS BEING
FORECASTED THAN WHAT HAS OCCURRED...THIS WOULD CAUSE MORE WIDESPREAD
QPF THAN WHAT IS ACTUALLY OCCURRING DUE TO CONVECTIVE PARAMETERS
BEING ACTIVATED IN THE MODELS. WITH THIS IN MIND...WILL GO WITH A
DRIER SCENARIO AND CUT POPS BACK WITH CHANCE POPS OVER THE WEST ONLY
THROUGH SUNDAY NIGHT. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO
THE GOING FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER THE
NORTHERN PLAINS 12Z MON WITH A RIDGE OVER THE EASTERN U.S. AND
TROUGHING ACROSS THE PLAINS. PATTERN CHANGES VERY LITTLE FOR 12Z TUE
WITH A SLIGHT EASTWARD MOVEMENT 12Z WED INTO THE UPPER MISSISSIPPI
RIVER VALLEY. THIS LOW AND TROUGH MOVE INTO THE UPPER GREAT LAKES
12Z THU. ONE THING WITH THIS PATTERN IS IT WILL BE SLOW TO PROGRESS
EASTWARD. LOOKS LIKE A DECENT CHANCE FOR WIDESPREAD RAIN STARTING
MON AND LASTING INTO WED AS THE TROUGH KICKS OUT. ON THU...DRIER AIR
STARTS TO WORK IN AS A COLD FRONT HEADS SOUTH WED NIGHT INTO THU AND
POPS SHOULD BE LOWER BY THEN. SHOULD ALSO BE A COOLING TREND THIS
FORECAST PERIOD WITH TEMPERATURES COOLING TO BELOW NORMAL STARTING
TUE ONWARD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 142 AM EDT FRI MAY 17 2013

ALTHOUGH HI CLDS WL BE ON THE INCREASE THRU TODAY...EXPECT VFR
CONDITIONS TO PREVAIL THRU THIS FCST PERIOD WITH DRY E WIND OUT OF
HUDSON BAY HI PRES. IF THIS HI RETREATS...SOME -SHRA MAY IMPACT IWD
THIS EVNG. BUT MENTIONED ONLY VCSH ATTM GIVEN LIKELY PERSISTENCE OF
DRY AIR ASSOCIATED WITH STUBBORN HUDSON BAY HI PRES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

UPDATE...JLA
SHORT TERM...JLA
LONG TERM...07
AVIATION...KC
MARINE...07

000
FXUS63 KAPX 171006
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
606 AM EDT FRI MAY 17 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT FRI MAY 17 2013

HIGH PRESSURE WILL REMAIN IN CONTROL OF NORTHERN MICHIGANS WEATHER
THROUGH TODAY...RESULTING IN DRY WEATHER UNDER PARTLY SUNNY SKIES
AND SEASONABLE TEMPERATURES. WARM AND MOIST AIR PRESSING INTO THE
MIDWEST AND GREAT LAKES WILL BRING A CHANCE FOR SHOWERS TO THE
NORTH WOODS OVER THE WEEKEND...MAINLY ON SATURDAY.

&&

.UPDATE...
ISSUED AT 606 AM EDT FRI MAY 17 2013

FORECAST APPEARS ON TRACK FOR THE MOMENT. SUBSTANTIAL HIGH CLOUDS
FROM UPSTREAM CONVECTION HAVE OVERSPREAD MUCH OF THE CWA...
ESPECIALLY NRN LOWER MICHIGAN. SATELLITE TRENDS REVEAL ABUNDANT
HIGHER CLOUD COVER UPSTREAM THAT WILL CONTINUE TO STREAM THROUGH
THE REGION TODAY. THUS PARTLY SUNNY TO OCCASIONALLY MOSTLY CLOUDY
SKIES SHOULD WORK OUT.

OTHERWISE...QUITE A FEW LOCATIONS ARE IN THE UPPER 30S WITH A FEW
SPOTS COLDER (PLN IS 32F). WARMEST LOCATIONS ARE IN THE SW
COUNTIES (TVC/FKS/MBL...ETC). CAN PROBABLY SAFELY TRIM THOSE
COUNTIES OUT OF THE FREEZE ADVISORY EARLY.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT FRI MAY 17 2013

OVERVIEW: FAIRLY PROGRESSIVE FLOW PATTERN ACROSS THE CONUS CURRENTLY
BUT STARTING TO BECOME MORE AMPLIFIED AS TROUGHINESS DEEPENS ALONG
THE WEST COAST...AND DOWNSTREAM RIDGING BUILDS THROUGH THE PLAINS
AND INTO THE GREAT LAKES. RIDGING GRADUALLY BUILDS INTO THE GREAT
LAKES HEADING THROUGH THE WEEKEND SIGNALING WARMER DAYS AHEAD.

MEANWHILE...HIGH PRESSURE HAS NUDGED IT/S WAY DOWN OUT OF ONTARIO
AND INTO THE WESTERN GREAT LAKES. ONGOING MCS ACTIVITY TO OUR
SOUTHWEST ACROSS IOWA...BUT WILL STAY WELL AWAY FROM US AS
MOISTURE/INSTABILITY REMAINS DISPLACED WELL OFF TO OUR WEST AND SOUTH.

TODAY...HIGH PRESSURE AND ANTECEDENT DRY AIRMASS WILL CONTINUE TO
DOMINATE THE REGION WITH NO PRECIP ANTICIPATED. HOWEVER...THERE IS
QUITE A BIT OF MID AND HIGH CLOUD COVER UPSTREAM FROM ONGOING
CONVECTION AS WELL AS INCREASING WARM ADVECTION ACROSS THE PLAINS.
THUS...WILL SEE VARIOUS ROUNDS OF MID AND HIGH CLOUD SLIDING THROUGH
THE REGION...LEADING TO PARTLY CLOUDY TO OCCASIONALLY MOSTLY CLOUDY
SKIES. TEMPERATURES...A LITTLE WARMER AS COMPARED TO THURSDAY WITH
HIGHS RANGING FROM THE MID 60S TO LOWER 70S.

FIRE WEATHER CONCERNS...DRY ANTECEDENT CONDITIONS PERSIST AND EXPECT
INLAND SFC DEWPOINTS WILL DIP INTO THE LOWER 30S DURING THE
AFTERNOON LIKE THURSDAY WITH MINIMUM RH VALUES GOING BELOW 25
PERCENT. HOWEVER...TEMPS WILL LARGELY REMAIN BELOW 75 FOR MOST AREAS
AND WINDS WILL BE FAIRLY LIGHT (UNDER 10 MPH). YES IT WILL BE DRY
BUT WITHOUT DECENT WIND...WILL NOT HAVE ELEVATED FIRE DANGER
MENTIONED IN THE HWO FOR TODAY.

TONIGHT...WARM AND MOIST AIR (HIGH THETA-E) BUILDS THROUGH THE
PLAINS AND THE UPPER MIDWEST THROUGH THE COURSE OF THE NIGHT WITH
THE STRONGEST SURGE/FORCING OCCURRING ACROSS THE NRN PLAINS AND UPPER
MIDWEST WHERE ONE OR MORE CONVECTIVE SYSTEMS WILL LIKELY BE ONGOING
OR DEVELOP. HERE AT HOME...NOT SO IMPRESSED. NW-SE ORIENTED THETA-E
GRADIENT WILL BE INCHING UP THROUGH STATE THROUGH THE COURSE OF THE
NIGHT. BUT AGAIN...MUCH STRONGER LOW LEVEL FLOW AND RESULTING
FORCING (MOIST CONVERGENCE) WILL REMAIN WELL WEST-NORTHWEST OF THE
CWA WHERE MOST CONVECTIVE ACTIVITY WILL BE CONFINED. SUPPOSE ITS
PLAUSIBLE WE GET A FEW ELEVATED SHOWERS TO DEVELOP ALONG THE
ADVANCING THETA-E GRADIENT ALTHOUGH LAPSE RATES ALOFT ARE JUST NOT
THAT SUPPORTIVE OF CONVECTION. IN THE END...FOR CONTINUITY AND
COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO MAINTAIN CHANCE
POPS FOR SHOWERS OVER NW LOWER MICHIGAN OVERNIGHT BUT HAVE TRIMMED
POPS BACK TO 30 PERCENT OR LESS.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM EDT FRI MAY 17 2013

A WARMER AND PROGRESSIVELY MORE MOIST SOUTHEASTERLY FLOW WILL LEAD
TO CHANCES FOR SHOWERS THIS WEEKEND. THERE WILL BE CHANCES FOR
SHOWERS AND EVEN THUNDERSTORMS EARLY NEXT WEEK WHICH WILL BECOME
LIKELY BY THE MIDDLE OF NEXT WEEK...AS A CUTOFF UPPER TROUGH
APPROACHES FROM OUR SOUTHWEST. FINALLY...CONDITIONS MOST LIKELY  DRY
OUT BY THURSDAY AS THIS SYSTEM RETREATS TO THE SOUTHEAST. THE MAIN
LONG TERM FORECAST CONCERNS REVOLVE AROUND POPS AND HOW MUCH IT WILL
WARM UP THIS WEEKEND INTO EARLY NEXT WEEK.

SATURDAY AND SUNDAY...MODELS ARE ONLY IN FAIR AGREEMENT ON THE
TIMING AND AMOUNT OF MOISTURE ADVECTION INTO THE REGION AS THETA-E
RIDGING APPROACHES THE FORECAST AREA BUT WEAKENS AS IT DOES SO. THIS
IS IN RESPONSE TO A DECAYING AREA OF LOW PRESSURE MOVING BY TO THE
NORTHWEST. IT IS STILL UNCERTAIN IF IT WILL MOISTEN UP ENOUGH ACROSS
NORTHERN MICHIGAN TO ACTUALLY RAIN...AS THE MAIN ACTION LOOKS TO
REMAIN TO OUR WEST. SO WILL BACK OFF ON POPS TO SLIGHT AND LOW
CHANCES FOR SHOWERS. HIGHS SATURDAY RANGING FROM THE MIDDLE 60S TO
MIDDLE 70S...WITH THE WARMER 70S TO LOWER 80S ON SUNDAY EXPECTED.
LOWS SATURDAY NIGHT IN THE MIDDLE 40S TO LOWER 50S.

MONDAY THROUGH THURSDAY...SHOWERS AND THUNDERSTORM CHANCES INCREASE
MONDAY THEN BECOME LIKELY MONDAY NIGHT INTO WEDNESDAY AS A CUTOFF
UPPER LEVEL TROUGH AND WARM FRONT APPROACH FROM THE SOUTHWEST.
EXTENDED MODELS THEN VARY ON THE TIMING OF DRYING FROM THE
NORTH...BUT WILL PENCIL THURSDAY IN AS A DRY DAY AS THIS SYSTEM IS
SHOWN TO SLOWLY RETREAT TO OUR SOUTHEAST. REMAINING WARM WITH HIGHS
IN THE 70S TO LOWER 80S MONDAY...FOLLOWED BY A SLOW COOLING TREND
WITH TEMPERATURES ENDING UP IN THE UPPER 50S TO LOWER 60S FOR HIGHS
BY THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 606 AM EDT FRI MAY 17 2013

SOLID VFR CONDITIONS THROUGH THE UPCOMING TAF FORECAST PERIOD...
BUT WITH GRADUALLY LOWERING CIGS THIS AFTERNOON AND TONIGHT. LIGHT
WINDS (UNDER 10 KNOTS) WITH WIND DIRECTIONS LAKE DOMINATED AT THE
TAF SITES.

&&

.MARINE...
ISSUED AT 352 AM EDT FRI MAY 17 2013

LIGHT WINDS/LOW WAVES WILL PREVAIL ON THE LAKES TODAY AND TONIGHT
WITH NO MARINE HEADLINES NEEDED. SOUTH-SOUTHEAST FLOW INCREASES
SATURDAY AND SATURDAY NIGHT AND A HANDFUL OF SMALL CRAFT ADVISORIES
MAY BE NEEDED. AT THAT TIME.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ016>036.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...BA
SYNOPSIS...AS
SHORT TERM...BA
LONG TERM...AS
AVIATION...BA
MARINE...BA

000
FXUS63 KMQT 170847
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
447 AM EDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 446 AM EDT FRI MAY 17 2013

IN CONFLUENT FLOW PATTERN ALOFT EXPECT HIGH PRESSURE TO EXPAND FROM
NORTHERN ONTARIO ACROSS GREAT LAKES TODAY. LIGHT WINDS OVER FAR EAST
ALONG THE RIDGE AXIS AND CLEARER SKIES HAVE ALLOWED TEMPS TO FALL
BLO 30 AT A FEW OF THE FIRE WX RAWS SITES. WARM FRONT STAYS WELL TO
SOUTHWEST OF UPR MICHIGAN TODAY...CURRENTLY FROM CENTRAL PLAINS INTO
NORTHERN OHIO VALLEY...ONLY ADVANCING INTO SOUTHERN MINNESOTA AND
SOUTHERN WISCONSIN BY THIS EVENING. A LOT OF MID CLOUDS OVER THE
UPPER LAKES REGION THIS MORNING. REGIONAL RADAR LOOP SHOWS MULTIPLE
RIBBONS OF SHRA ACROSS NORTHERN MINNESOTA AND ALSO AS FAR NORTH AS
CENTRAL WISCONSIN. BOTH AREAS OF SHOWERS ARE SUPPORTED BY MID-LEVEL
FRONTOGENESIS AND H85-H7 MOISTURE ADVECTION. MORE ORGANIZED CLUSTER
OF SHRA AND NMRS TSRA OCCURRING OVER NORTHERN IA INTO FAR SOUTHERN
MINNESOTA ALONG H85 WARM FRONT/H95 MOISTURE CONVERGENCE AND ON EDGE
OF 1-6KM MUCAPE GRADIENT.

PRIMARY QUESTION IS RAIN POTENTIAL/COVERAGE THROUGH TONIGHT. TO SUM
UP HAVE WENT WITH DRIER FCST FARTHER NORTH INTO UPR MICHIGAN
COMPARED TO WHAT MANY MODELS SHOW. THINKING THAT MAJORITY OF MODELS
ARE OVERDONE WITH PRECIP GIVEN BUILDING SFC-H85 HIGH PRESSURE RIDGE
FROM NORTHERN ONTARIO INTO THE LOWER GREAT LAKES AND LACK OF STRONG
MOISTURE ADVECTION AS FAR NORTH AS UPR MICHIGAN. SHRA OVR NORTHERN
MINNESOTA EXPECTED TO DISSIPATE AS RIGHT ENTRANCE REGION OF JET OVER
ONTARIO FADES THROUGH 15Z. ISLE ROYALE COULD STILL GET CLIPPED WITH
ISOLD SHRA...REST OF WESTERN CWA SHOULD STAY DRY. MEANWHILE...H7
MOISTURE TRANSPORT MARKING EDGE OF SHRA OVER CNTRL WISCONSIN PRETTY
WELL RIGHT NOW. MOISTURE ADVECTION AT H7 AND H8-H7 FRONTOGENESIS IS
FORECAST TO IMPACT FAR SCNTRL CWA BY LATE MORNING AND REST OF THE
DAY. HAVE BROUGHT LOW CHANCE POPS INTO MENOMINEE COUNTY...BUT SHOULD
BE SHARP CUTOFF FARTHER NORTH FOR PRECIP GIVEN DOWNWARD MOTION ON
DECENDING BRANCH OF THE MID-LEVEL FRONTOGENESIS. NAM/GEM-REGIONAL
PROBABLY TOO DRY TODAY OVER THE SOUTHERN CWA...BUT SEEM BETTER FIT
COMPARED TO GFS/ECMWF. SHOULD NOTE THAT EVEN THESE MODELS HAVE
TRENDED FARTHER SOUTH WITH AXIS OF QPF COMPARED TO MODEL RUNS FROM
THURSDAY.

ELSEWHERE...SCT-BKN MID CLOUDS SHOULD BE THE STORY ALONG WITH LGT
EASTERLY SFC WINDS WITH ORIGIN OUT OF SFC HIGH AND WELL TO NORTH OF
THE SFC WARM FRONT. THINNING OF MID CLOUDS OVERHEAD MAY OCCUR AS
RIGHT ENTRANCE REGION FORCING FROM JET OVER ONTARIO DIMINISHES.
TEMPS SHOULD HAVE NON-UNIFORM GRADIENTS DUE TO CLOUDS AND SFC WIND
TRAJECTORIES. WARMEST READINGS AROUND 70 DEGREES IN THE FAR EAST.
COOLEST READINGS IN 50S ALONG LK SUPERIOR WITH PREVAILING ONSHORE
FLOW. MAY ALSO SEE COOLER POCKET OF TEMPS SET UP ALONG WI BORDER DUE
TO THICKER CLOUD COVER AND POTENTIAL PRECIP. UNLIKE LAST FEW
DAYS...H9-H85 LIMITED DRY AIR IN THE H9-H85 LAYER SHOULD PROHIBIT
DEEP MIXING AND VERY LOW HUMIDITIES.

TONIGHT...LARGE SCALE FORCING CHANGES START TO INCREASE CHANCES FOR
PRECIP TO MAKE IT INTO AT LEAST MORE OF UPR MICHIGAN. UPPER LEVEL
TROUGH MOVES INTO NORTHERN ROCKIES WITH SFC-H85 LOWS BECOMING MORE
ORGANIZED OVER NORTHERN PLAINS. WINDS BECOME MORE SOUTHERLY OVER
UPPER MISSISSIPPI RIVER VALLEY IN RESPONSE. H85 BAROCLINIC ZONE
LIFTS TOWARD WESTERN LK SUPERIOR AND NORTHERN WISCONSIN THROUGH THE
NIGHT. ISENTROPIC ASCENT ALONG THE BOUNDARY SUPPORTS CHANCES OF SHRA
INCREASING. SHARPEST MOISTURE TRANSPORT INTO THE H85 BOUNDARY IS
OVER NORTHERN MINNESOTA AND INTO WESTERN LK SUPERIOR...WITH A
TAPERING OFF FARTHER EAST. NOT MUCH H7 MOISTURE ADVECTION FARTHER
EAST EITHER. REALLY PREFER THE GEM-REGIONAL/NAM/NCEP WRF IDEA FOR
CONVECTION TONIGHT...FAVORING MAJORITY OF SHRA/TSRA OVER NORTHERN
MINNESOTA INTO SOUTHWEST UPR MICHIGAN. EDGE OF CAPE GRADIENT ALSO
SUPPORTS BETTER TSRA POTENTIAL INTO SW UPR MICHIGAN FROM LATE
EVENING ONWARD. BY LATE TONIGHT...MAJORITY OF MODELS SHOVE THE
CONVECTION...OR AT LEAST REMNANTS OF IT...INTO CNTRL UPR MICHIGAN.
SUPPOSE THIS MAY OCCUR DO TO LEAD SHORTWAVE PRESSING ACROSS NORTHERN
MINNESOTA AND H7 MOISTURE TRANSPORT VECTORS TURNING MORE WEST TO
EAST. NOT SOLD ON A LOT OF PRECIP MAKING IT WELL TO EAST OF GRADIENT
OF INSTABILITY ALOFT...SO JUST USED SLIGHT CHANCE POPS OTHER THAN
OVER FAR WESTERN CWA. MINS TONIGHT HELD UP BY THICKENING CLOUDS AND
PRECIP. TEMPS OVER INTERIOR EAST MAY DROP INTO 30S...BUT NOT AS COOL
AS EARLY THIS MORNING. 40S TO AROUND 50 FOR MINS EVERYWHERE ELSE.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 446 AM EDT FRI MAY 17 2013

NAM SHOWS A 500 MB RIDGE OVER THE UPPER GREAT LAKES 12Z SAT WITH
TROUGHING IN THE ROCKY MOUNTAINS. THE RIDGE REMAINS 12Z SUN WITH A
SHORTWAVE ON THE WESTERN SIDE IN THE DAKOTAS. TROUGHING THEN MOVES
IN THE NORTHERN PLAINS WITH A CLOSED LOW 12Z MON. NAM SHOWS SOME
DEEPER MOISTURE AND Q-VECTOR CONVERGENCE REMAINING OVER THE AREA 12Z
SAT ONWARD.

DID MAKE A MAJOR CHANGE TO THE GOING FORECAST AND WENT DRIER OVER
THE EASTERN HALF OF THE CWA THROUGH SUN NIGHT. AM FINDING IT HARD TO
BELIEVE WITH THE SLOW MOVEMENT OF THE SYSTEM TO THE WEST...BUILDING
UPPER RIDGE TO THE EAST AND A SFC HIGH PRESSURE SYSTEM BRINGING IN
DRY EAST TO SOUTHEAST FLOW...THAT PCPN WOULD BE AS WIDESPREAD AS IT
IS IN THE ECMWF...NAM AND GFS MODELS AND THINK THEY ARE ALL OVERDONE
WITH HIGHER SFC DEW POINTS BEING OVERFORECASTED WHICH HAS BEEN THE
CASE FOR THE PAST SEVERAL WEEKS. WITH HIGHER DEW POINTS BEING
FORECASTED THAN WHAT HAS OCCURRED...THIS WOULD CAUSE MORE WIDESPREAD
QPF THAN WHAT IS ACTUALLY OCCURRING DUE TO CONVECTIVE PARAMETERS
BEING ACTIVATED IN THE MODELS. WITH THIS IN MIND...WILL GO WITH A
DRIER SCENARIO AND CUT POPS BACK WITH CHANCE POPS OVER THE WEST ONLY
THROUGH SUNDAY NIGHT. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO
THE GOING FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER THE
NORTHERN PLAINS 12Z MON WITH A RIDGE OVER THE EASTERN U.S. AND
TROUGHING ACROSS THE PLAINS. PATTERN CHANGES VERY LITTLE FOR 12Z TUE
WITH A SLIGHT EASTWARD MOVEMENT 12Z WED INTO THE UPPER MISSISSIPPI
RIVER VALLEY. THIS LOW AND TROUGH MOVE INTO THE UPPER GREAT LAKES
12Z THU. ONE THING WITH THIS PATTERN IS IT WILL BE SLOW TO PROGRESS
EASTWARD. LOOKS LIKE A DECENT CHANCE FOR WIDESPREAD RAIN STARTING
MON AND LASTING INTO WED AS THE TROUGH KICKS OUT. ON THU...DRIER AIR
STARTS TO WORK IN AS A COLD FRONT HEADS SOUTH WED NIGHT INTO THU AND
POPS SHOULD BE LOWER BY THEN. SHOULD ALSO BE A COOLING TREND THIS
FORECAST PERIOD WITH TEMPERATURES COOLING TO BELOW NORMAL STARTING
TUE ONWARD.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 142 AM EDT FRI MAY 17 2013

ALTHOUGH HI CLDS WL BE ON THE INCREASE THRU TODAY...EXPECT VFR
CONDITIONS TO PREVAIL THRU THIS FCST PERIOD WITH DRY E WIND OUT OF
HUDSON BAY HI PRES. IF THIS HI RETREATS...SOME -SHRA MAY IMPACT IWD
THIS EVNG. BUT MENTIONED ONLY VCSH ATTM GIVEN LIKELY PERSISTENCE OF
DRY AIR ASSOCIATED WITH STUBBORN HUDSON BAY HI PRES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 AM EDT FRI MAY 17 2013

HEADING THRU THE WEEKEND INTO EARLY NEXT WEEK...PRESSURE GRADIENT
OVER THE UPPER LAKES WILL SLOWLY TIGHTEN BTWN LOW PRES SLOWLY MOVING
FROM THE WRN PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY AND HIGH
PRES BUILDING IN THE VCNTY OF WRN HUDSON BAY. THIS WILL LEAD TO
EASTERLY WINDS GRADUALLY INCREASING INTO GENERALLY THE 15-25KT
RANGE. COULD BE SOME PERIODS OF HIGHER WINDS AT TIMES EARLY NEXT
WEEK...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE FUNNELING/CHANNELING
WILL ENHANCE THE WINDS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...07
AVIATION...KC
MARINE...07