000
FXUS63 KDVN 241743
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1243 PM CDT FRI MAY 24 2013
.SYNOPSIS...
ISSUED AT 322 AM CDT FRI MAY 24 2013
HIGH PRESSURE CENTERED OVER THE LAKE SUPERIOR REGION WAS PROVIDING
CLEAR AND COOL CONDITIONS ACROSS THE AREA EARLY THIS MORNING. CLOSER
TO THE CENTER OF THE HIGH...TEMPERATURES ACROSS NORTHERN WI WERE IN
THE 30S WITH POCKETS OF UPPER 20S. FURTHER SOUTH...A NORTHEAST
BREEZE IN THE LIGHT ANTICYCLONIC FLOW WAS HOLDING TEMPERATURES IN
THE 40S WITH A FEW POCKETS OF UPPER 30S FROM NORTHERN IL INTO
EASTERN IA. FURTHER AWAY FROM LAKE MI...SOUTHEAST IA AND WEST
CENTRAL IL WERE IN THE LOWER 50S. IN THE UPPER LEVELS...00Z ANALYSIS
SHOWED A LONG WAVE TROUGH FROM EASTERN CANADA INTO THE GREAT
LAKES...A RIDGE TO THE WEST ACROSS THE CENTRAL AND NORTHERN
PLAINS...WHILE A CLOSED LOW WAS FURTHER WEST OVER THE PACIFIC NW. AT
850 MB...GULF MOISTURE WAS FEEDING N-NW INTO THE HIGH PLAINS IN THE
SOUTHERLY FLOW BETWEEN A RIDGE OVER THE UPPER MS VALLEY AND A LOW
OVER THE INTERMOUNTAIN WEST. THIS RETURN FLOW IS EXPECTED TO VEER
MORE N-NE BY TONIGHT IN RESPONSE TO A SERIES OF UPPER LEVEL
SHORTWAVES THAT WILL BEGIN TO FLATTEN THE 500 MB RIDGE IN THE
CENTRAL CONUS. THE ELEVATED THETAE ADVECTION WILL LIKELY LEAD TO MCS
FORMATION THAT SHOULD SPILL INTO THE LOCAL AREA BY SATURDAY
MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT FRI MAY 24 2013
INITIAL FOCUS IS ON TEMPERATURES TODAY...FOLLOWED BY THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS LATE TONIGHT. BLOCKY PATTERN ALOFT WILL
KEEP HIGH PRESSURE ANCHORED JUST EAST OF THE FORECAST AREA THROUGH
TODAY. THIS...ALONG WITH A VERY DRY AIR MASS IN PLACE AND UPPER LEVEL
SUBSIDENCE DOWNSTREAM FROM THE UPPER LEVEL RIDGE SHOULD PROVIDE
CLEAR SKIES. AFTER STARTING OUT IN THE UPPER 30S IN A FEW LOCATIONS
THIS MORNING...THE DRY AIR WILL PERMIT A LARGER THAN NORMAL DIURNAL
RANGE. CONSIDERING THE LIGHT SOUTHEAST FLOW OUT OF THE GREAT
LAKES AND MIXING TO JUST ABOVE 900 MB...A BLEND OF MOS GUIDANCE
HIGHS FROM THE LOWER 60S NORTHEAST TO THE UPPER 60S WEST LOOKS
REASONABLE. THIS AIR MASS TRAJECTORY WILL KEEP DEW POINTS IN THE 30S
THROUGH MOST OF THE DAY...PROVIDING COMFORTABLY LOW HUMIDITY.
TONIGHT...THE DEPARTING SURFACE RIDGE WILL CONTINUE TO PROVIDE A
WEAK LOW LEVEL EAST TO SOUTHEAST FLOW OF DRY AIR. HOWEVER...THIS
WILL BE OVERRUN BY WARM ADVECTION AND THEN INCREASING MOISTURE AT
850 MB TOWARD SATURDAY MORNING. AN MCS WILL LIKELY DEVELOP ON THIS
THETAE ADVECTION WELL TO THE WEST TO NORTHWEST OF THE FORECAST AREA
LATE IN THE EVENING. THIS WOULD THEN FOLLOW PROPAGATION VECTORS
EAST TO SOUTHEAST INTO EASTERN IA BY 12Z...IN A DISSIPATING MODE AS
IT MOVES AWAY FROM A MORE FAVORABLE MOISTURE FEED AND ENCOUNTERS DRY
AIR IN THE LOW LEVELS. AT THE SAME TIME...WEAK ELEVATED CONVERGENCE
ALONG WITH INCREASING MID LEVEL TEMPERATURE LAPSE RATES AND THETAE
LAPSE RATES MAY LEAD TO ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS...FOCUSED OVER SOUTHEAST IA OR EAST CENTRAL AND
NORTHEAST IA...DEPENDING ON THE MODEL TOWARD SUNRISE. CONSIDERING
THE ABOVE...HAVE GONE WITH LIKELY POPS ROUGHLY WEST OF THE HIGHWAY
218 CORRIDOR AFTER 1 AM...WITH POPS DIMINISHING TO CHANCE TO SLIGHT
CHANCES IN IL. INCREASING CLOUDS AND SLIGHTLY STRONGER SURFACE WINDS
WILL HOLD MINS WARMER THAN THIS MORNING...BUT STILL BELOW NORMAL...
FROM THE LOWER 40S EAST AND NORTHEAST TO THE LOWER 50S IN SE IA AND
NE MO. SHEETS
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI MAY 24 2013
THE LONG TERM TIME FRAME LOOKS LIKE AN UNSETTLED PERIOD WITH
PLENTY OF OPPORTUNITIES FOR RAIN AND DRY WEATHER...THOUGH LITTLE
IN THE WAY OF SEVERE WEATHER POTENTIAL. MODELS ARE IN GENERAL
AGREEMENT THROUGH DAY 5 BUT THEN DIVERGE FOR DAYS 6 AND 7.
WHILE THE RIDGE MAINTAINS ITSELF OVER THE CENTRAL U.S.THROUGH
MONDAY...SEVERAL WEAK WAVES EMBEDDED IN THE RIDGE ARE PROBLEMATIC
FOR PINPOINTING PRECIP CHANCES. IN ADDITION THE LOCATION OF THE
SURFACE AND 850 FRONTS WILL ALSO BE KEY PLAYERS.
DECAYING MCS SATURDAY WILL PRECEDE A WEAK SHORT WAVE TROUGH
PASSAGE SATURDAY NIGHT INTO SUNDAY. THIS SHOULD FOCUS STORM
CHANCES ALONG THE 850MB FRONT MOVING INTO OUR CWA...WITH ANOTHER
NOCTURNAL MCS INITIATING TO OUR WEST AND PERSISTING INTO SUNDAY.
ON MONDAY...THE SURFACE WARM FRONT SHIFTS CLOSER TO THE CWA
PROVIDING ANOTHER FOCUSING MECHANISM FOR STORMS. HOWEVER...OVERALL
THIS HOLIDAY WEEKEND INSTABILITY IS LIMITED AND FORCING...BOTH
MID LEVEL SHORTWAVE TROUGHS AND LOW-LEVEL JET INTERACTIONS WITH
THE 850MB BOUNDARY ARE WEAK. SO I WANT TO AVOID THE IMPRESSION OF
A TOTAL WASHOUT FOR THE WEEKEND...AS THERE SHOULD BE PLENTY OF
DRY WEATHER IN BETWEEN THE RAIN CHANCES. THE CHALLENGE IS TRYING
TO PIN THOSE PERIODS...AND IT IS DIFFICULT TO DO SO WITH SUCH
SUBTLE FEATURES. BUT THE PATTERN SEEMS TO FAVOR NOCTURNAL
INITIATION AND DECAY EARLY THE NEXT DAY.
BY MID WEEK THE ACTIVITY MOSTLY SHIFTS TO THE NORTH THOUGH NOT
COMPLETELY OUT OF THE AREA...SO POP CHANCES WILL DIMINISH AS TEMPS
MODERATE.
MODELS DIVERGE LATE IN THE WEEK WITH THE GFS BRINGING A PACIFIC
TROUGH INTO THE NORTHERN ROCKIES/PLAINS INDICATING A LITTLE MORE
ENERGETIC WEATHER FOR US...WHILE THE 12Z ECMWF CUTS OFF A LOW TO
OUR SOUTHWEST ALLOWING THE RIDGE TO DOMINATE AND TREND US TOWARD
QUIET WEATHER. THE 00Z GFS RUN IS WELL WITHIN THE MEAN OF THE 12Z
ENSEMBLE...AND THE 00Z ECMWF SEEMS TO BE TRENDING THIS WAY TOO. SO
OPTED FOR THE MORE ENERGETIC PATTERN WHICH IS REFLECTED IN POPS.
WOLF
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1232 PM CDT FRI MAY 24 2013
VFR THROUGH THIS EVENING AND EVEN MIDNIGHT IN LINGERING PRESENCE
OF HIGH PRESSURE. BUT FORCING SWATH ALOFT/WARM AIR ADVECTION WING
TAKING SHAPE CURRENTLY ACRS EASTERN SD INTO THE MO RVR VALLEY WILL
LOOK TO BRING HIGH BASED SHOWERS/ROOTED ABOVE 4K FT AGL AND POSSIBLY
A THUNDERSTORM TO THE WESTERN VCNTY OF CID BY 1 AM CDT...AND INTO
DBQ AND MLI BY 3 AM CDT SAT MORNING. A ELEVATED SYSTEM OF SHOWERS
AND EMBEDDED THUNDERSTORMS STARTING TO ENCROACH MVFR CIGS MAY
BECOME MORE WIDESPREAD AND IMPACT MOST TERMINALS FROM 11Z-18Z SAT
MORNING. TEMPORARY BOUTS OF MVFR VSBYS BY HEAVIER RAIN POSSIBLE
SAT MORNING AS WELL EVEN IF CIGS REMAIN ABOVE 3K FT AGL. UNTIL
THEN...LIGHT EAST SOUTHEAST SFC WINDS THIS AFTERNOON TO BECOME
MAINLY SOUTHEASTERLY TONIGHT AT 5-10 KTS. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...WOLF
AVIATION...12
000
FXUS63 KDVN 241117
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
617 AM CDT FRI MAY 24 2013
.SYNOPSIS...
ISSUED AT 322 AM CDT FRI MAY 24 2013
HIGH PRESSURE CENTERED OVER THE LAKE SUPERIOR REGION WAS PROVIDING
CLEAR AND COOL CONDITIONS ACROSS THE AREA EARLY THIS MORNING. CLOSER
TO THE CENTER OF THE HIGH...TEMPERATURES ACROSS NORTHERN WI WERE IN
THE 30S WITH POCKETS OF UPPER 20S. FURTHER SOUTH...A NORTHEAST
BREEZE IN THE LIGHT ANTICYCLONIC FLOW WAS HOLDING TEMPERATURES IN
THE 40S WITH A FEW POCKETS OF UPPER 30S FROM NORTHERN IL INTO
EASTERN IA. FURTHER AWAY FROM LAKE MI...SOUTHEAST IA AND WEST
CENTRAL IL WERE IN THE LOWER 50S. IN THE UPPER LEVELS...00Z ANALYSIS
SHOWED A LONGWAVE TROUGH FROM EASTERN CANADA INTO THE GREAT
LAKES...A RIDGE TO THE WEST ACROSS THE CENTRAL AND NORTHERN
PLAINS...WHILE A CLOSED LOW WAS FURTHER WEST OVER THE PACIFIC NW. AT
850 MB...GULF MOISTURE WAS FEEDING N-NW INTO THE HIGH PLAINS IN THE
SOUTHERLY FLOW BETWEEN A RIDGE OVER THE UPPER MS VALLEY AND A LOW
OVER THE INTERMOUNTAIN WEST. THIS RETURN FLOW IS EXPECTED TO VEER
MORE N-NE BY TONIGHT IN RESPONSE TO A SERIES OF UPPER LEVEL
SHORTWAVES THAT WILL BEGIN TO FLATTEN THE 500 MB RIDGE IN THE
CENTRAL CONUS. THE ELEVATED THETAE ADVECTION WILL LIKELY LEAD TO MCS
FORMATION THAT SHOULD SPILL INTO THE LOCAL AREA BY SATURDAY
MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT FRI MAY 24 2013
INITIAL FOCUS IS ON TEMPERATURES TODAY...FOLLOWED BY THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS LATE TONIGHT. BLOCKY PATTERN ALOFT WILL
KEEP HIGH PRESSURE ANCHORED JUST EAST OF THE FORECAST AREA THROUGH
TODAY. THIS...ALONG WITH A VERY DRY AIR MASS IN PLACE AND UPPER LEVEL
SUBSIDENCE DOWNSTREAM FROM THE UPPER LEVEL RIDGE SHOULD PROVIDE
CLEAR SKIES. AFTER STARTING OUT IN THE UPPER 30S IN A FEW LOCATIONS
THIS MORNING...THE DRY AIR WILL PERMIT A LARGER THAN NORMAL DIURNAL
RANGE. CONSIDERING THE LIGHT SOUTHEAST FLOW OUT OF THE GREAT
LAKES AND MIXING TO JUST ABOVE 900 MB...A BLEND OF MOS GUIDANCE
HIGHS FROM THE LOWER 60S NORTHEAST TO THE UPPER 60S WEST LOOKS
REASONABLE. THIS AIR MASS TRAJECTORY WILL KEEP DEW POINTS IN THE 30S
THROUGH MOST OF THE DAY...PROVIDING COMFORTABLY LOW HUMIDITY.
TONIGHT...THE DEPARTING SURFACE RIDGE WILL CONTINUE TO PROVIDE A
WEAK LOW LEVEL EAST TO SOUTHEAST FLOW OF DRY AIR. HOWEVER...THIS
WILL BE OVERRUN BY WARM ADVECTION AND THEN INCREASING MOISTURE AT
850 MB TOWARD SATURDAY MORNING. AN MCS WILL LIKELY DEVELOP ON THIS
THETAE ADVECTION WELL TO THE WEST TO NORTHWEST OF THE FORECAST AREA
LATE IN THE EVENING. THIS WOULD THEN FOLLOW PROPAGATION VECTORS
EAST TO SOUTHEAST INTO EASTERN IA BY 12Z...IN A DISSIPATING MODE AS
IT MOVES AWAY FROM A MORE FAVORABLE MOISTURE FEED AND ENCOUNTERS DRY
AIR IN THE LOW LEVELS. AT THE SAME TIME...WEAK ELEVATED CONVERGENCE
ALONG WITH INCREASING MID LEVEL TEMPERATURE LAPSE RATES AND THETAE
LAPSE RATES MAY LEAD TO ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS...FOCUSED OVER SOUTHEAST IA OR EAST CENTRAL AND
NORTHEAST IA...DEPENDING ON THE MODEL TOWARD SUNRISE. CONSIDERING
THE ABOVE...HAVE GONE WITH LIKELY POPS ROUGHLY WEST OF THE HIGHWAY
218 CORRIDOR AFTER 1 AM...WITH POPS DIMINISHING TO CHANCE TO SLIGHT
CHANCES IN IL. INCREASING CLOUDS AND SLIGHTLY STRONGER SURFACE WINDS
WILL HOLD MINS WARMER THAN THIS MORNING...BUT STILL BELOW NORMAL...
FROM THE LOWER 40S EAST AND NORTHEAST TO THE LOWER 50S IN SE IA AND
NE MO. SHEETS
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM CDT FRI MAY 24 2013
THE LONG TERM TIME FRAME LOOKS LIKE AN UNSETTLED PERIOD WITH
PLENTY OF OPPORTUNITIES FOR RAIN AND DRY WEATHER...THOUGH LITTLE
IN THE WAY OF SEVERE WEATHER POTENTIAL. MODELS ARE IN GENERAL
AGREEMENT THROUGH DAY 5 BUT THEN DIVERGE FOR DAYS 6 AND 7.
WHILE THE RIDGE MAINTAINS ITSELF OVER THE CENTRAL U.S.THROUGH
MONDAY...SEVERAL WEAK WAVES EMBEDDED IN THE RIDGE ARE PROBLEMATIC
FOR PINPOINTING PRECIP CHANCES. IN ADDITION THE LOCATION OF THE
SURFACE AND 850 FRONTS WILL ALSO BE KEY PLAYERS.
DECAYING MCS SATURDAY WILL PRECEDE A WEAK SHORT WAVE TROUGH
PASSAGE SATURDAY NIGHT INTO SUNDAY. THIS SHOULD FOCUS STORM
CHANCES ALONG THE 850MB FRONT MOVING INTO OUR CWA...WITH ANOTHER
NOCTURNAL MCS INITIATING TO OUR WEST AND PERSISTING INTO SUNDAY.
ON MONDAY...THE SURFACE WARM FRONT SHIFTS CLOSER TO THE CWA
PROVIDING ANOTHER FOCUSING MECHANISM FOR STORMS. HOWEVER...OVERALL
THIS HOLIDAY WEEKEND INSTABILITY IS LIMITED AND FORCING...BOTH
MID LEVEL SHORTWAVE TROUGHS AND LOW-LEVEL JET INTERACTIONS WITH
THE 850MB BOUNDARY ARE WEAK. SO I WANT TO AVOID THE IMPRESSION OF
A TOTAL WASHOUT FOR THE WEEKEND...AS THERE SHOULD BE PLENTY OF
DRY WEATHER IN BETWEEN THE RAIN CHANCES. THE CHALLENGE IS TRYING
TO PIN THOSE PERIODS...AND IT IS DIFFICULT TO DO SO WITH SUCH
SUBTLE FEATURES. BUT THE PATTERN SEEMS TO FAVOR NOCTURNAL
INITIATION AND DECAY EARLY THE NEXT DAY.
BY MID WEEK THE ACTIVITY MOSTLY SHIFTS TO THE NORTH THOUGH NOT
COMPLETELY OUT OF THE AREA...SO POP CHANCES WILL DIMINISH AS TEMPS
MODERATE.
MODELS DIVERGE LATE IN THE WEEK WITH THE GFS BRINGING A PACIFIC
TROUGH INTO THE NORTHERN ROCKIES/PLAINS INDICATING A LITTLE MORE
ENERGETIC WEATHER FOR US...WHILE THE 12Z ECMWF CUTS OFF A LOW TO
OUR SOUTHWEST ALLOWING THE RIDGE TO DOMINATE AND TREND US TOWARD
QUIET WEATHER. THE 00Z GFS RUN IS WELL WITHIN THE MEAN OF THE 12Z
ENSEMBLE...AND THE 00Z ECMWF SEEMS TO BE TRENDING THIS WAY TOO. SO
OPTED FOR THE MORE ENERGETIC PATTERN WHICH IS REFLECTED IN POPS.
WOLF
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 616 AM CDT FRI MAY 24 2013
HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL PROVIDE MOSTLY
CLEAR SKIES AND LIGHT EAST TO SOUTHEAST WINDS ACROSS THE EASTERN
IOWA AND NORTHWEST ILLINOIS TERMINALS TODAY. LATE TONIGHT...
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. THE GREATEST
CHANCES WILL BE IN THE VICINITY OF THE CID AND DBQ
TERMINALS...WHERE PROB30 GROUPS HAVE BEEN INTRODUCED.
OTHERWISE...CONDITIONS WILL REMAIN VFR THROUGHOUT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...WOLF
AVIATION...SHEETS
000
FXUS63 KDVN 240822
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
322 AM CDT FRI MAY 24 2013
.SYNOPSIS...
ISSUED AT 245 AM CDT FRI MAY 24 2013
HIGH PRESSURE CENTERED OVER THE LAKE SUPERIOR REGION WAS PROVIDING
CLEAR AND COOL CONDITIONS ACROSS THE AREA EARLY THIS MORNING. CLOSER
TO THE CENTER OF THE HIGH...TEMPERATURES ACROSS NORTHERN WI WERE IN
THE 30S WITH POCKETS OF UPPER 20S. FURTHER SOUTH...A NORTHEAST
BREEZE IN THE LIGHT ANTICYCLONIC FLOW WAS HOLDING TEMPERATURES IN
THE 40S WITH A FEW POCKETS OF UPPER 30S FROM NORTHERN IL INTO
EASTERN IA. FURTHER AWAY FROM LAKE MI...SOUTHEAST IA AND WEST
CENTRAL IL WERE IN THE LOWER 50S. IN THE UPPER LEVELS...00Z ANALYSIS
SHOWED A LONGWAVE TROUGH FROM EASTERN CANADA INTO THE GREAT
LAKES...A RIDGE TO THE WEST ACROSS THE CENTRAL AND NORTHERN
PLAINS...WHILE A CLOSED LOW WAS FURTHER WEST OVER THE PACIFIC NW. AT
850 MB...GULF MOISTURE WAS FEEDING N-NW INTO THE HIGH PLAINS IN THE
SOUTHERLY FLOW BETWEEN A RIDGE OVER THE UPPER MS VALLEY AND A LOW
OVER THE INTERMOUNTAIN WEST. THIS RETURN FLOW IS EXPECTED TO VEER
MORE N-NE BY TONIGHT IN RESPONSE TO A SERIES OF UPPER LEVEL
SHORTWAVES THAT WILL BEGIN TO FLATTEN THE 500 MB RIDGE IN THE
CENTRAL CONUS. THE ELEVATED THETAE ADVECTION WILL LIKELY LEAD TO MCS
FORMATION THAT SHOULD SPILL INTO THE LOCAL AREA BY SATURDAY
MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 245 AM CDT FRI MAY 24 2013
INITIAL FOCUS IS ON TEMPERATURES TODAY...FOLLOWED BY THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS LATE TONIGHT. BLOCKY PATTERN ALOFT WILL
KEEP HIGH PRESSURE ANCHORED JUST EAST OF THE FORECAST AREA THROUGH
TODAY. THIS...ALONG WITH A VERY DRY AIR MASS IN PLACE AND UPPER LEVEL
SUBSIDENCE DOWNSTREAM FROM THE UPPER LEVEL RIDGE SHOULD PROVIDE
CLEAR SKIES. AFTER STARTING OUT IN THE UPPER 30S IN A FEW LOCATIONS
THIS MORNING...THE DRY AIR WILL PERMIT A LARGER THAN NORMAL DIURNAL
RANGE. CONSIDERING THE LIGHT SOUTHEAST FLOW OUT OF THE GREAT
LAKES AND MIXING TO JUST ABOVE 900 MB...A BLEND OF MOS GUIDANCE
HIGHS FROM THE LOWER 60S NORTHEAST TO THE UPPER 60S WEST LOOKS
REASONABLE. THIS AIR MASS TRAJECTORY WILL KEEP DEW POINTS IN THE 30S
THROUGH MOST OF THE DAY...PROVIDING COMFORTABLY LOW HUMIDITY.
TONIGHT...THE DEPARTING SURFACE RIDGE WILL CONTINUE TO PROVIDE A
WEAK LOW LEVEL EAST TO SOUTHEAST FLOW OF DRY AIR. HOWEVER...THIS
WILL BE OVERRUN BY WARM ADVECTION AND THEN INCREASING MOISTURE AT
850 MB TOWARD SATURDAY MORNING. AN MCS WILL LIKELY DEVELOP ON THIS
THETAE ADVECTION WELL TO THE WEST TO NORTHWEST OF THE FORECAST AREA
LATE IN THE EVENING. THIS WOULD THEN FOLLOW PROPAGATION VECTORS
EAST TO SOUTHEAST INTO EASTERN IA BY 12Z...IN A DISSIPATING MODE AS
IT MOVES AWAY FROM A MORE FAVORABLE MOISTURE FEED AND ENCOUNTERS DRY
AIR IN THE LOW LEVELS. AT THE SAME TIME...WEAK ELEVATED CONVERGENCE
ALONG WITH INCREASING MID LEVEL TEMPERATURE LAPSE RATES AND THETAE
LAPSE RATES MAY LEAD TO ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS...FOCUSED OVER SOUTHEAST IA OR EAST CENTRAL AND
NORTHEAST IA...DEPENDING ON THE MODEL TOWARD SUNRISE. CONSIDERING
THE ABOVE...HAVE GONE WITH LIKELY POPS ROUGHLY WEST OF THE HIGHWAY
218 CORRIDOR AFTER 1 AM...WITH POPS DIMINISHING TO CHANCE TO SLIGHT
CHANCES IN IL. INCREASING CLOUDS AND SLIGHTLY STRONGER SURFACE WINDS
WILL HOLD MINS WARMER THAN THIS MORNING...BUT STILL BELOW NORMAL...
FROM THE LOWER 40S EAST AND NORTHEAST TO THE LOWER 50S IN SE IA AND
NE MO. SHEETS
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 245 AM CDT FRI MAY 24 2013
THE LONG TERM TIME FRAME LOOKS LIKE AN UNSETTLED PERIOD WITH
PLENTY OF OPPORTUNITIES FOR RAIN AND DRY WEATHER...THOUGH LITTLE
IN THE WAY OF SEVERE WEATHER POTENTIAL. MODELS ARE IN GENERAL
AGREEMENT THROUGH DAY 5 BUT THEN DIVERGE FOR DAYS 6 AND 7.
WHILE THE RIDGE MAINTAINS ITSELF OVER THE CENTRAL U.S.THROUGH
MONDAY...SEVERAL WEAK WAVES EMBEDDED IN THE RIDGE ARE PROBLEMATIC
FOR PINPOINTING PRECIP CHANCES. IN ADDITION THE LOCATION OF THE
SURFACE AND 850 FRONTS WILL ALSO BE KEY PLAYERS.
DECAYING MCS SATURDAY WILL PRECEDE A WEAK SHORT WAVE TROUGH
PASSAGE SATURDAY NIGHT INTO SUNDAY. THIS SHOULD FOCUS STORM
CHANCES ALONG THE 850MB FRONT MOVING INTO OUR CWA...WITH ANOTHER
NOCTURNAL MCS INITIATING TO OUR WEST AND PERSISTING INTO SUNDAY.
ON MONDAY...THE SURFACE WARM FRONT SHIFTS CLOSER TO THE CWA
PROVIDING ANOTHER FOCUSING MECHANISM FOR STORMS. HOWEVER...OVERALL
THIS HOLIDAY WEEKEND INSTABILITY IS LIMITED AND FORCING...BOTH
MID LEVEL SHORTWAVE TROUGHS AND LOW-LEVEL JET INTERACTIONS WITH
THE 850MB BOUNDARY ARE WEAK. SO I WANT TO AVOID THE IMPRESSION OF
A TOTAL WASHOUT FOR THE WEEKEND...AS THERE SHOULD BE PLENTY OF
DRY WEATHER IN BETWEEN THE RAIN CHANCES. THE CHALLENGE IS TRYING
TO PIN THOSE PERIODS...AND IT IS DIFFICULT TO DO SO WITH SUCH
SUBTLE FEATURES. BUT THE PATTERN SEEMS TO FAVOR NOCTURNAL
INITIATION AND DECAY EARLY THE NEXT DAY.
BY MID WEEK THE ACTIVITY MOSTLY SHIFTS TO THE NORTH THOUGH NOT
COMPLETELY OUT OF THE AREA...SO POP CHANCES WILL DIMINISH AS TEMPS
MODERATE.
MODELS DIVERGE LATE IN THE WEEK WITH THE GFS BRINGING A PACIFIC
TROUGH INTO THE NORTHERN ROCKIES/PLAINS INDICATING A LITTLE MORE
ENERGETIC WEATHER FOR US...WHILE THE 12Z ECMWF CUTS OFF A LOW TO
OUR SOUTHWEST ALLOWING THE RIDGE TO DOMINATE AND TREND US TOWARD
QUIET WEATHER. THE 00Z GFS RUN IS WELL WITHIN THE MEAN OF THE 12Z
ENSEMBLE...AND THE 00Z ECMWF SEEMS TO BE TRENDING THIS WAY TOO. SO
OPTED FOR THE MORE ENERGETIC PATTERN WHICH IS REFLECTED IN POPS.
WOLF
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1139 PM CDT THU MAY 23 2013
VFR CONDITIONS EXPECTED THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS
OVERNIGHT WILL SLOWLY INCREASE OUT OF THE SOUTHEAST FRIDAY MORNING BUT
STILL AT OR BELOW 10 KTS. FRIDAY EVENING THUNDERSTORMS ARE
EXPECTED TO GENERATE OUT OVER THE PLAINS WHICH WILL MOVE TOWARDS
THE TERMINALS. THESE WILL SPREAD HIGH CLOUDS ABOVE 10KFT AFTER
00Z...BUT NO THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE TERMINALS
UNTIL AFTER 06Z. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...WOLF
AVIATION...LE
000
FXUS63 KDVN 240443
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1143 PM CDT THU MAY 23 2013
.SYNOPSIS...
ISSUED AT 216 PM CDT THU MAY 23 2013
LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE NOSING
DOWN ACRS THE UPPER MIDWEST WITH ASSOCIATED PRESSURE RISE MAX
FIELDS STILL OCCUPYING MUCH OF THE LOCAL CWA AND INTO THE
SOUTHWESTERN GRT LKS. CU/STRATOCU FIELDS ACRS THE CWA HANGING ON
SOME AND EVEN REFORMING IN AREAS OF EARLIER CLEARING...BUT
FLATTENING RISING TRENDS ALSO NOTED AND INCOMING DRYING/SUBSIDENCE
FIELDS SEEN ON WATER VAPOR IMAGERY WILL WIN OUT INTO THE EVENING.
ALOFT...W/V IMAGERY ALSO INDICATING L/W TROF TAKING SHAPE ACRS THE
WESTERN GRT LKS WHILE OMEGA UPPER RIDGE GETS SQUEEZED ACRS THE
NORTHERN PLAINS AND WEST CENTRAL CANADA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
TONIGHT...INCOMING RIDGE TO CONTINUE TO BRING ALONG WITH IT CLEARING
SUBSIDENCE THIS EVENING...WHILE SFC WINDS DECREASE AND TRY TO DECOUPLE
INTO EARLY FRI MORNING. INCOMING COOL ADVECTED AIR MASS AND DRYING
SFC DPTS SUPPORT WIDESPREAD LOWS FROM 40-45 DEGREES...BUT THE
NORTHEASTERN THIRD OF THE DVN CWA MAY LOOK TO COOL INTO THE UPPER
30S LIKE WHAT IS ALREADY ADVERTISED. H85 MB RIDGE COLD RULE EVEN
SUPPORTS SOME MID 30S IN THOSE AREAS WHICH COULD MEAN PATCHY
FROST. BUT CAME UP WITH LOWS SIMILAR TO WHAT IS ADVERTISED AND
WILL NOT CHANGE MUCH WHAT IS ONGOING...THUS WILL NOT MENTION FROST
AND LOWS FEW DEGREES ABOVE RECORD LEVELS. HOPEFULLY WILL JUST BE A
HEAVY DEW. WILL NOT MENTION FOG AS WELL WITH DRY SFC DPT
INFLUX...BUT SOME RIVER VALLEY FOG WILL PROBABLY OCCUR.
FRI...AFTER A COOL START...WARM AIR ADVECTION ALOFT BY VEERING LLVL
FLOW WILL LEAD TO BUILDING INVERSION FROM H875 TO NEAR H75 MB
THROUGH 00Z SAT. THIS COULD LIMIT MIXING AND KEEP HIGHS MORE IN
THE LOWER TO MID 60S. BUT WITH PLENTY OF INSOLATION...EXPECT
DEEPER MIXING THERMALS TO HELP SOME AREAS MAKE INTO THE UPPER
60S/NEAR 70...SO WILL ADVERTISE MID TO UPPER 60S WIDESPREAD. SOME
CIRRUS TO TRY AND SPILL IN FROM THE WEST OFF PLAINS CONVECTION LATE IN
THE AFTERNOON..OTHERWISE A SUNNY DAY. ..12..
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
THE EXTENDED REMAINS POTENTIALLY VERY WET...STORMY...AND A CHALLENGE
TO ACCURATELY FORECAST TEMPERATURES. AS MIGHT BE THE CASE ANYTIME
THIS SET OF UNCERTAIN VARIABLES IS USED IN ONE SENTENCE DURING THE
WARM MONTHS OF THE YEAR...THIS IS ALL DUE TO WEST TO EAST STALLED
BOUNDARY.
MODELS HAVE TRENDED SOMEWHAT CLOSER TO A BLEND BETWEEN THE
CONSISTENTLY SOUTHERN ECMWF...AND THE CONSISTENTLY FARTHER NORTH
GFS. THE BALANCE OF THE TWO CAMPS REMAINS NORTH WITH THE
GFS/NAM/GEM...AND SOUTH WITH THE UKMET AND ECMWF. THIS IS AGAIN
PRIMARILY DUE TO HOW THE MODELS HANDLE THE HIGH PRESSURE OVER THE
OHIO VALLEY IN THE WAKE OF A STRONG EAST COAST SYSTEM. FOR OUR
FORECAST...WE REMAIN UNDER THE THREAT OF ELEVATED STORMS...AS
SEVERAL ROUNDS OF LOW LEVEL JET INDUCED MCS AFFECT LOCATIONS NORTH
OF THE SURFACE FRONT. THIS HAS BEEN THE CASE OVERNIGHT AND TODAY
OVER OKLAHOMA...AND WAS ENTIRELY MISSED BY THE 00Z ECMWF WHICH
APPEARS TOO FAR SOUTH WITH THE QPF AND FORCING TODAY.
THUS...OUR FORECAST IS A BLEND OF THE MODELS...YET DOES NOT FAVOR A
LIGHT RAIN SCENARIO...VS A PREFERRED ELEVATED SHOWER AND THUNDERSTORM
THREAT. THAT IS NOT TO SAY THAT A STRATIFORM RAIN REGION OR TWO WILL
AFFECT THE CWA THIS WEEKEND...WITH PERIODS OF TIME WITHOUT THUNDER
TAKING PLACE.
MODELS CONTINUE TO SHOW MOISTURE CONVERGENCE...WITH PWAT VALUES OVER
1 INCH SATURDAY NIGHT THROUGH TUESDAY...THUS...REPEAT ROUNDS OF
RAIN/THUNDER ARE EXPECTED...WITH INCREASING AMOUNTS OF WIDESPREAD
HEAVY RAINFALL POTENTIAL.
AS WE APPROACH MID WEEK...MODELS SUGGEST THE BOUNDARY WILL LIFT
NORTH...AS THE UPPER PATTERN AMPLIFIES. THIS COULD ALLOW FOR HEAT TO
BUILD IN WITH CAPPING...WHICH THE 00Z ECMWF DID...BUT IT IS FAR FROM
CERTAIN AS THE 12Z ECMWF KEEPS THE FRONT NEARBY WITH ACTIVE...AND
LIKELY SEVERE MCS POTENTIAL.
THUS...WE GENERALLY WILL BE QUITE COOL OVER THE WEEKEND AS RAIN
FALLS THROUGH THE DRY DEWPOINT AIR DURING THE ADVECTION PROCESS...
THEN AS THE AIRMASS TRANSITIONS TO WARM SECTOR...WE SHOULD PUSH
HIGHS WELL INTO THE 70S AND 80S FOR MID WEEK.
ERVIN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1139 PM CDT THU MAY 23 2013
VFR CONDITIONS EXPECTED THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS
OVERNIGHT WILL SLOWLY INCREASE OUT OF THE SOUTHEAST FRIDAY MORNING BUT
STILL AT OR BELOW 10 KTS. FRIDAY EVENING THUNDERSTORMS ARE
EXPECTED TO GENERATE OUT OVER THE PLAINS WHICH WILL MOVE TOWARDS
THE TERMINALS. THESE WILL SPREAD HIGH CLOUDS ABOVE 10KFT AFTER
00Z...BUT NO THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT THE TERMINALS
UNTIL AFTER 06Z. LE
&&
.CLIMATE...
ISSUED AT 216 PM CDT THU MAY 23 2013
RECORD LOWS FOR MAY 24...
MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...LE
000
FXUS63 KDVN 232333
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
633 PM CDT THU MAY 23 2013
.SYNOPSIS...
ISSUED AT 216 PM CDT THU MAY 23 2013
LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE NOSING
DOWN ACRS THE UPPER MIDWEST WITH ASSOCIATED PRESSURE RISE MAX
FIELDS STILL OCCUPYING MUCH OF THE LOCAL CWA AND INTO THE
SOUTHWESTERN GRT LKS. CU/STRATOCU FIELDS ACRS THE CWA HANGING ON
SOME AND EVEN REFORMING IN AREAS OF EARLIER CLEARING...BUT
FLATTENING RISING TRENDS ALSO NOTED AND INCOMING DRYING/SUBSIDENCE
FIELDS SEEN ON WATER VAPOR IMAGERY WILL WIN OUT INTO THE EVENING.
ALOFT...W/V IMAGERY ALSO INDICATING L/W TROF TAKING SHAPE ACRS THE
WESTERN GRT LKS WHILE OMEGA UPPER RIDGE GETS SQUEEZED ACRS THE
NORTHERN PLAINS AND WEST CENTRAL CANADA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
TONIGHT...INCOMING RIDGE TO CONTINUE TO BRING ALONG WITH IT CLEARING
SUBSIDENCE THIS EVENING...WHILE SFC WINDS DECREASE AND TRY TO DECOUPLE
INTO EARLY FRI MORNING. INCOMING COOL ADVECTED AIR MASS AND DRYING
SFC DPTS SUPPORT WIDESPREAD LOWS FROM 40-45 DEGREES...BUT THE
NORTHEASTERN THIRD OF THE DVN CWA MAY LOOK TO COOL INTO THE UPPER
30S LIKE WHAT IS ALREADY ADVERTISED. H85 MB RIDGE COLD RULE EVEN
SUPPORTS SOME MID 30S IN THOSE AREAS WHICH COULD MEAN PATCHY
FROST. BUT CAME UP WITH LOWS SIMILAR TO WHAT IS ADVERTISED AND
WILL NOT CHANGE MUCH WHAT IS ONGOING...THUS WILL NOT MENTION FROST
AND LOWS FEW DEGREES ABOVE RECORD LEVELS. HOPEFULLY WILL JUST BE A
HEAVY DEW. WILL NOT MENTION FOG AS WELL WITH DRY SFC DPT
INFLUX...BUT SOME RIVER VALLEY FOG WILL PROBABLY OCCUR.
FRI...AFTER A COOL START...WARM AIR ADVECTION ALOFT BY VEERING LLVL
FLOW WILL LEAD TO BUILDING INVERSION FROM H875 TO NEAR H75 MB
THROUGH 00Z SAT. THIS COULD LIMIT MIXING AND KEEP HIGHS MORE IN
THE LOWER TO MID 60S. BUT WITH PLENTY OF INSOLATION...EXPECT
DEEPER MIXING THERMALS TO HELP SOME AREAS MAKE INTO THE UPPER
60S/NEAR 70...SO WILL ADVERTISE MID TO UPPER 60S WIDESPREAD. SOME
CIRRUS TO TRY AND SPILL IN FROM THE WEST OFF PLAINS CONVECTION LATE IN
THE AFTERNOON..OTHERWISE A SUNNY DAY. ..12..
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
THE EXTENDED REMAINS POTENTIALLY VERY WET...STORMY...AND A CHALLENGE
TO ACCURATELY FORECAST TEMPERATURES. AS MIGHT BE THE CASE ANYTIME
THIS SET OF UNCERTAIN VARIABLES IS USED IN ONE SENTENCE DURING THE
WARM MONTHS OF THE YEAR...THIS IS ALL DUE TO WEST TO EAST STALLED
BOUNDARY.
MODELS HAVE TRENDED SOMEWHAT CLOSER TO A BLEND BETWEEN THE
CONSISTENTLY SOUTHERN ECMWF...AND THE CONSISTENTLY FARTHER NORTH
GFS. THE BALANCE OF THE TWO CAMPS REMAINS NORTH WITH THE
GFS/NAM/GEM...AND SOUTH WITH THE UKMET AND ECMWF. THIS IS AGAIN
PRIMARILY DUE TO HOW THE MODELS HANDLE THE HIGH PRESSURE OVER THE
OHIO VALLEY IN THE WAKE OF A STRONG EAST COAST SYSTEM. FOR OUR
FORECAST...WE REMAIN UNDER THE THREAT OF ELEVATED STORMS...AS
SEVERAL ROUNDS OF LOW LEVEL JET INDUCED MCS AFFECT LOCATIONS NORTH
OF THE SURFACE FRONT. THIS HAS BEEN THE CASE OVERNIGHT AND TODAY
OVER OKLAHOMA...AND WAS ENTIRELY MISSED BY THE 00Z ECMWF WHICH
APPEARS TOO FAR SOUTH WITH THE QPF AND FORCING TODAY.
THUS...OUR FORECAST IS A BLEND OF THE MODELS...YET DOES NOT FAVOR A
LIGHT RAIN SCENARIO...VS A PREFERRED ELEVATED SHOWER AND THUNDERSTORM
THREAT. THAT IS NOT TO SAY THAT A STRATIFORM RAIN REGION OR TWO WILL
AFFECT THE CWA THIS WEEKEND...WITH PERIODS OF TIME WITHOUT THUNDER
TAKING PLACE.
MODELS CONTINUE TO SHOW MOISTURE CONVERGENCE...WITH PWAT VALUES OVER
1 INCH SATURDAY NIGHT THROUGH TUESDAY...THUS...REPEAT ROUNDS OF
RAIN/THUNDER ARE EXPECTED...WITH INCREASING AMOUNTS OF WIDESPREAD
HEAVY RAINFALL POTENTIAL.
AS WE APPROACH MID WEEK...MODELS SUGGEST THE BOUNDARY WILL LIFT
NORTH...AS THE UPPER PATTERN AMPLIFIES. THIS COULD ALLOW FOR HEAT TO
BUILD IN WITH CAPPING...WHICH THE 00Z ECMWF DID...BUT IT IS FAR FROM
CERTAIN AS THE 12Z ECMWF KEEPS THE FRONT NEARBY WITH ACTIVE...AND
LIKELY SEVERE MCS POTENTIAL.
THUS...WE GENERALLY WILL BE QUITE COOL OVER THE WEEKEND AS RAIN
FALLS THROUGH THE DRY DEWPOINT AIR DURING THE ADVECTION PROCESS...
THEN AS THE AIRMASS TRANSITIONS TO WARM SECTOR...WE SHOULD PUSH
HIGHS WELL INTO THE 70S AND 80S FOR MID WEEK.
ERVIN
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 630 PM CDT THU MAY 23 2013
VFR CONDITIONS EXPECTED THE NEXT 24 HOURS. NORTHEAST WINDS AROUND
10 KTS TO FALL OFF TO LIGHT AND VARIABLE OVERNIGHT...THEN INCREASE
OUT OF THE SOUTHEAST BUT STILL AT OR LESS THAN 10 KTS. LE
&&
.CLIMATE...
ISSUED AT 216 PM CDT THU MAY 23 2013
RECORD LOWS FOR MAY 24...
MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...LE
000
FXUS63 KDVN 231952
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
252 PM CDT THU MAY 23 2013
.SYNOPSIS...
ISSUED AT 216 PM CDT THU MAY 23 2013
LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE NOSING
DOWN ACRS THE UPPER MIDWEST WITH ASSOCIATED PRESSURE RISE MAX
FIELDS STILL OCCUPYING MUCH OF THE LOCAL CWA AND INTO THE
SOUTHWESTERN GRT LKS. CU/STRATOCU FIELDS ACRS THE CWA HANGING ON
SOME AND EVEN REFORMING IN AREAS OF EARLIER CLEARING...BUT
FLATTENING RISING TRENDS ALSO NOTED AND INCOMING DRYING/SUBSIDENCE
FIELDS SEEN ON WATER VAPOR IMAGERY WILL WIN OUT INTO THE EVENING.
ALOFT...W/V IMAGERY ALSO INDICATING L/W TROF TAKING SHAPE ACRS THE
WESTERN GRT LKS WHILE OMEGA UPPER RIDGE GETS SQUEEZED ACRS THE
NORTHERN PLAINS AND WEST CENTRAL CANADA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
TONIGHT...INCOMING RIDGE TO CONTINUE TO BRING ALONG WITH IT CLEARING
SUBSIDENCE THIS EVENING...WHILE SFC WINDS DECREASE AND TRY TO DECOUPLE
INTO EARLY FRI MORNING. INCOMING COOL ADVECTED AIR MASS AND DRYING
SFC DPTS SUPPORT WIDESPREAD LOWS FROM 40-45 DEGREES...BUT THE
NORTHEASTERN THIRD OF THE DVN CWA MAY LOOK TO COOL INTO THE UPPER
30S LIKE WHAT IS ALREADY ADVERTISED. H85 MB RIDGE COLD RULE EVEN
SUPPORTS SOME MID 30S IN THOSE AREAS WHICH COULD MEAN PATCHY
FROST. BUT CAME UP WITH LOWS SIMILAR TO WHAT IS ADVERTISED AND
WILL NOT CHANGE MUCH WHAT IS ONGOING...THUS WILL NOT MENTION FROST
AND LOWS FEW DEGREES ABOVE RECORD LEVELS. HOPEFULLY WILL JUST BE A
HEAVY DEW. WILL NOT MENTION FOG AS WELL WITH DRY SFC DPT
INFLUX...BUT SOME RIVER VALLEY FOG WILL PROBABLY OCCUR.
FRI...AFTER A COOL START...WARM AIR ADVECTION ALOFT BY VEERING LLVL
FLOW WILL LEAD TO BUILDING INVERSION FROM H875 TO NEAR H75 MB
THROUGH 00Z SAT. THIS COULD LIMIT MIXING AND KEEP HIGHS MORE IN
THE LOWER TO MID 60S. BUT WITH PLENTY OF INSOLATION...EXPECT
DEEPER MIXING THERMALS TO HELP SOME AREAS MAKE INTO THE UPPER
60S/NEAR 70...SO WILL ADVERTISE MID TO UPPER 60S WIDESPREAD. SOME
CIRRUS TO TRY AND SPILL IN FROM THE WEST OFF PLAINS CONVECTION LATE IN
THE AFTERNOON..OTHERWISE A SUNNY DAY. ..12..
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 216 PM CDT THU MAY 23 2013
THE EXTENDED REMAINS POTENTIALLY VERY WET...STORMY...AND A CHALLENGE
TO ACCURATELY FORECAST TEMPERATURES. AS MIGHT BE THE CASE ANYTIME
THIS SET OF UNCERTAIN VARIABLES IS USED IN ONE SENTENCE DURING THE
WARM MONTHS OF THE YEAR...THIS IS ALL DUE TO WEST TO EAST STALLED
BOUNDARY.
MODELS HAVE TRENDED SOMEWHAT CLOSER TO A BLEND BETWEEN THE
CONSISTENTLY SOUTHERN ECMWF...AND THE CONSISTENTLY FARTHER NORTH
GFS. THE BALANCE OF THE TWO CAMPS REMAINS NORTH WITH THE
GFS/NAM/GEM...AND SOUTH WITH THE UKMET AND ECMWF. THIS IS AGAIN
PRIMARILY DUE TO HOW THE MODELS HANDLE THE HIGH PRESSURE OVER THE
OHIO VALLEY IN THE WAKE OF A STRONG EAST COAST SYSTEM. FOR OUR
FORECAST...WE REMAIN UNDER THE THREAT OF ELEVATED STORMS...AS
SEVERAL ROUNDS OF LOW LEVEL JET INDUCED MCS AFFECT LOCATIONS NORTH
OF THE SURFACE FRONT. THIS HAS BEEN THE CASE OVERNIGHT AND TODAY
OVER OKLAHOMA...AND WAS ENTIRELY MISSED BY THE 00Z ECMWF WHICH
APPEARS TOO FAR SOUTH WITH THE QPF AND FORCING TODAY.
THUS...OUR FORECAST IS A BLEND OF THE MODELS...YET DOES NOT FAVOR A
LIGHT RAIN SCENARIO...VS A PREFERRED ELEVATED SHOWER AND THUNDERSTORM
THREAT. THAT IS NOT TO SAY THAT A STRATIFORM RAIN REGION OR TWO WILL
AFFECT THE CWA THIS WEEKEND...WITH PERIODS OF TIME WITHOUT THUNDER
TAKING PLACE.
MODELS CONTINUE TO SHOW MOISTURE CONVERGENCE...WITH PWAT VALUES OVER
1 INCH SATURDAY NIGHT THROUGH TUESDAY...THUS...REPEAT ROUNDS OF
RAIN/THUNDER ARE EXPECTED...WITH INCREASING AMOUNTS OF WIDESPREAD
HEAVY RAINFALL POTENTIAL.
AS WE APPROACH MID WEEK...MODELS SUGGEST THE BOUNDARY WILL LIFT
NORTH...AS THE UPPER PATTERN AMPLIFIES. THIS COULD ALLOW FOR HEAT TO
BUILD IN WITH CAPPING...WHICH THE 00Z ECMWF DID...BUT IT IS FAR FROM
CERTAIN AS THE 12Z ECMWF KEEPS THE FRONT NEARBY WITH ACTIVE...AND
LIKELY SEVERE MCS POTENTIAL.
THUS...WE GENERALLY WILL BE QUITE COOL OVER THE WEEKEND AS RAIN
FALLS THROUGH THE DRY DEWPOINT AIR DURING THE ADVECTION PROCESS...
THEN AS THE AIRMASS TRANSITIONS TO WARM SECTOR...WE SHOULD PUSH
HIGHS WELL INTO THE 70S AND 80S FOR MID WEEK.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU MAY 23 2013
SOME LINGERING MVFR CIGS THROUGH 20Z...OTHERWISE CU FIELD SHOULD
CONTINUE TO LIFT THROUGH VFR LEVELS AND MIX OUT/DECREASE THROUGH
EARLY EVENING. NORTH TO NORTHEAST WINDS OF 10-15 KTS WITH HIGHER
GUSTS TO BECOME LIGHT EASTERLY BY LATE EVENING AS CANADIAN HIGH
PRESSURE TAKES HOLD FROM THE NORTH. DRIER BOUNDARY LAYER INFLUX
FROM THE NORTH/NE SHOULD ALSO INHIBIT MUCH OF ANY FOG DEVELOPMENT
TONIGHT EXCEPT IN RIVER VALLEYS AWAY FROM THE TAF SITES. MAINLY
CLEAR AND VFR FOR MUCH OF FRI. ..12..
&&
.CLIMATE...
ISSUED AT 216 PM CDT THU MAY 23 2013
RECORD LOWS FOR MAY 24...
MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...12
000
FXUS63 KDVN 231748
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1248 PM CDT THU MAY 23 2013
.SYNOPSIS...
ISSUED AT 253 AM CDT THU MAY 23 2013
DEFORMATION ZONE MOVING SOUTH ACROSS AREA AT 2 AM WITH AREAS OF
MOSTLY LIGHT RAIN AND DRIZZLE NOTED. DUBUQUE THOUGH IN PAST 2
HOURS HAS PICKED UP .23 INCHES. AWIPS DISTANCE AND TIME FEATURE
SHOWS END OF PRECIPITATION TO PASS QUICKLY ACROSS AREA BETWEEN
11-16Z. UPPER AIR AND SURFACE SHOWS SEASONABLY STRONG AND COOL
CANADIAN AIR MASS TO MOVE IN WITH BELOW NORMAL TEMPERATURES NEXT
24 HOURS AND THEN UNSETTLED WEATHER INTO EARLY NEXT WEEK WITH
WAVES ALONG STALLED FRONT TO OUR SOUTHEAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT THU MAY 23 2013
TODAY...USE OF NOWCAST TOOLS SUPPORTS LIGHT RAIN AND PATCHY DRIZZLE TO
SLIDE SOUTHEAST BY MID MORNING. SKIES SHOULD CLEAR FROM NORTH TO SOUTH
BETWEEN 14-21Z AS STRONG SUBSIDENCE AND COOLER AND DRIER MOVES IN.
NORTHERLY WINDS WILL BE BREEZY AT 15 TO 25 MPH INTO LATE AFTERNOON
AS HIGHS REACH MOSTLY INTO THE MIDDLE 60S AND SOME LOWER 60S IN
THE EAST AND NORTHEAST. THESE TEMPERATURES ARE ABOUT 10 DEGREES
BELOW NORMAL.
TONIGHT...CLEAR SKIES...STRONG SUBSIDENCE AND CALM WINDS BY EARLY
OVERNIGHT HOURS WILL ALLOW FOR STRONG DECOUPLING OF BL AND MINS IN
THE NORTHEAST 1/3 AREA TO SEE UPPER 30S WITH ISOLATED COLD AIR
DRAINAGE SPOTS POSSIBLY SEEING MIDDLE 30S WITH PATCHY FROST RISK.
THIS IS THE MAIN CONCERN FOR DAY SHIFT TO REASSESS. MINS WILL BE
WITHIN 2-4 DEGREES OF RECORDS AT MLI/DBQ (SEE CLIMATE SECTION BELOW).
NICHOLS
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 253 AM CDT THU MAY 23 2013
DRY AND COOL CONDITIONS WILL BE SEEN FRIDAY WITH TEMPERATURES BELOW
NORMAL.
INITIALLY...FRIDAY EVENING WILL BE DRY. RETURN FLOW ALOFT IS PROGGED
TO BRING MOISTURE BACK NORTH INTO THE MIDWEST. SCHC POPS WERE PLACED
IN THE EXTREME WESTERN PART OF THE CWFA DURING THE LATE EVENING
HOURS. THE BETTER LLJ AND MOISTURE RETURN IS STILL WEST OF THE CWFA
AT MIDNIGHT. THE MCS/LIFT TOOLS GENERALLY SUGGEST SOMETHING JUST
WEST OF THE CWFA AT MIDNIGHT THAT SHOULD STRATIFY OUT DUE TO THE DRY
AIR OVER THE AREA.
AFTER MIDNIGHT...THE LLJ VEERS INTO THE CWFA WITH A RESPECTABLE
THETA E GRADIENT MOVING ACROSS THE AREA. INTERNALLY...THE MODELS ARE
INDICATING SIGNIFICANT EVAPORATIVE COOLING DUE TO THE DRY AIR
FEEDING IN FROM THE EAST. THUS THE MCS THAT FORMS IN THE PLAINS
WOULD STRATIFY OUT AS IT MOVES INTO THE AREA. THE EXTREME
WEST/SOUTHWEST WOULD HAVE THE BEST POTENTIAL AT SEEING A
THUNDERSTORM WHILE THE REMAINDER OF THE AREA SHOULD SEE SHOWERS.
SATURDAY WILL BE EXTREMELY COOL WITH MAINLY STRATIFORM RAIN ACROSS
THE AREA AS STRONG EVAPORATIVE COOLING CONTINUES. ANY THUNDER WOULD
BE ACROSS THE EXTREME SOUTHWEST/SOUTH PARTS OF THE CWFA AS THE
NOCTURNAL MCS CONTINUES TO DECAY.
SATURDAY NIGHT THE NEXT DISTURBANCE WILL DEVELOP AN MCS IN THE
PLAINS THAT TOPS THE RIDGE INTO THE AREA. AGAIN RELATIVELY DRY AIR
FEEDING IN FROM THE EAST SHOULD RESULT IN THE MCS STRATIFYING OUT AS
IT REACHES THE AREA. ANY THUNDER WOULD BE ISOLATED AND ACROSS THE
SOUTH THIRD AT MOST.
SUNDAY ON...
THE MODEL CONSENSUS CONTINUES AN ACTIVE WEATHER PATTERN ACROSS THE
MIDWEST WITH NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE OVER THE
AREA. THE OVERALL SET UP IS COMPARABLE TO A MID SUMMER RING OF FIRE.
THUS MCS EVENTS ARE EXPECTED TO DEVELOP AND MOVE INTO THE AREA AT
NIGHT WITH THE MCS DECAYING ACROSS THE AREA DURING THE DAY TIME.
BOUNDARIES LEFT OVER FROM EACH MCS EVENT WILL PROVIDE THE FOCUS FOR
DIURNAL CONVECTION DURING THE AFTERNOON AND EVENING.
THE MODEL CONSENSUS HAS CHC POPS FROM SUNDAY THROUGH WEDNESDAY
REFLECTING THIS SCENARIO. THERE WILL BE PERIODS OF DRY WX BUT THEY
CANNOT BE RESOLVED DUE TO SMOOTHING OF THE MODEL FEATURES.
TEMPERATURES WILL REMAIN BELOW NORMAL ON SUNDAY FOLLOWED BY
MODERATING TEMPERATURES MONDAY THROUGH WEDNESDAY.
08
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU MAY 23 2013
SOME LINGERING MVFR CIGS THROUGH 20Z...OTHERWISE CU FIELD SHOULD
CONTINUE TO LIFT THROUGH VFR LEVELS AND MIX OUT/DECREASE THROUGH
EARLY EVENING. NORTH TO NORTHEAST WINDS OF 10-15 KTS WITH HIGHER
GUSTS TO BECOME LIGHT EASTERLY BY LATE EVENING AS CANADIAN HIGH
PRESSURE TAKES HOLD FROM THE NORTH. DRIER BOUNDARY LAYER INFLUX
FROM THE NORTH/NE SHOULD ALSO INHIBIT MUCH OF ANY FOG DEVELOPMENT
TONIGHT EXCEPT IN RIVER VALLEYS AWAY FROM THE TAF SITES. MAINLY
CLEAR AND VFR FOR MUCH OF FRI. ..12..
&&
.CLIMATE...
ISSUED AT 253 AM CDT THU MAY 23 2013
RECORD LOWS FOR MAY 24...
MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...12
CLIMATE...NICHOLS
000
FXUS63 KDVN 230814
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
314 AM CDT THU MAY 23 2013
.SYNOPSIS...
ISSUED AT 253 AM CDT THU MAY 23 2013
DEFORMATION ZONE MOVING SOUTH ACROSS AREA AT 2 AM WITH AREAS OF
MOSTLY LIGHT RAIN AND DRIZZLE NOTED. DUBUQUE THOUGH IN PAST 2
HOURS HAS PICKED UP .23 INCHES. AWIPS DISTANCE AND TIME FEATURE
SHOWS END OF PRECIPITATION TO PASS QUICKLY ACROSS AREA BETWEEN
11-16Z. UPPER AIR AND SURFACE SHOWS SEASONABLY STRONG AND COOL
CANADIAN AIR MASS TO MOVE IN WITH BELOW NORMAL TEMPERATURES NEXT
24 HOURS AND THEN UNSETTLED WEATHER INTO EARLY NEXT WEEK WITH
WAVES ALONG STALLED FRONT TO OUR SOUTHEAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT THU MAY 23 2013
TODAY...USE OF NOWCAST TOOLS SUPPORTS LIGHT RAIN AND PATCHY DRIZZLE TO
SLIDE SOUTHEAST BY MID MORNING. SKIES SHOULD CLEAR FROM NORTH TO SOUTH
BETWEEN 14-21Z AS STRONG SUBSIDENCE AND COOLER AND DRIER MOVES IN.
NORTHERLY WINDS WILL BE BREEZY AT 15 TO 25 MPH INTO LATE AFTERNOON
AS HIGHS REACH MOSTLY INTO THE MIDDLE 60S AND SOME LOWER 60S IN
THE EAST AND NORTHEAST. THESE TEMPERATURES ARE ABOUT 10 DEGREES
BELOW NORMAL.
TONIGHT...CLEAR SKIES...STRONG SUBSIDENCE AND CALM WINDS BY EARLY
OVERNIGHT HOURS WILL ALLOW FOR STRONG DECOUPLING OF BL AND MINS IN
THE NORTHEAST 1/3 AREA TO SEE UPPER 30S WITH ISOLATED COLD AIR
DRAINAGE SPOTS POSSIBLY SEEING MIDDLE 30S WITH PATCHY FROST RISK.
THIS IS THE MAIN CONCERN FOR DAY SHIFT TO REASSESS. MINS WILL BE
WITHIN 2-4 DEGREES OF RECORDS AT MLI/DBQ (SEE CLIMATE SECTION BELOW).
NICHOLS
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 253 AM CDT THU MAY 23 2013
DRY AND COOL CONDITIONS WILL BE SEEN FRIDAY WITH TEMPERATURES BELOW
NORMAL.
INITIALLY...FRIDAY EVENING WILL BE DRY. RETURN FLOW ALOFT IS PROGGED
TO BRING MOISTURE BACK NORTH INTO THE MIDWEST. SCHC POPS WERE PLACED
IN THE EXTREME WESTERN PART OF THE CWFA DURING THE LATE EVENING
HOURS. THE BETTER LLJ AND MOISTURE RETURN IS STILL WEST OF THE CWFA
AT MIDNIGHT. THE MCS/LIFT TOOLS GENERALLY SUGGEST SOMETHING JUST
WEST OF THE CWFA AT MIDNIGHT THAT SHOULD STRATIFY OUT DUE TO THE DRY
AIR OVER THE AREA.
AFTER MIDNIGHT...THE LLJ VEERS INTO THE CWFA WITH A RESPECTABLE
THETA E GRADIENT MOVING ACROSS THE AREA. INTERNALLY...THE MODELS ARE
INDICATING SIGNIFICANT EVAPORATIVE COOLING DUE TO THE DRY AIR
FEEDING IN FROM THE EAST. THUS THE MCS THAT FORMS IN THE PLAINS
WOULD STRATIFY OUT AS IT MOVES INTO THE AREA. THE EXTREME
WEST/SOUTHWEST WOULD HAVE THE BEST POTENTIAL AT SEEING A
THUNDERSTORM WHILE THE REMAINDER OF THE AREA SHOULD SEE SHOWERS.
SATURDAY WILL BE EXTREMELY COOL WITH MAINLY STRATIFORM RAIN ACROSS
THE AREA AS STRONG EVAPORATIVE COOLING CONTINUES. ANY THUNDER WOULD
BE ACROSS THE EXTREME SOUTHWEST/SOUTH PARTS OF THE CWFA AS THE
NOCTURNAL MCS CONTINUES TO DECAY.
SATURDAY NIGHT THE NEXT DISTURBANCE WILL DEVELOP AN MCS IN THE
PLAINS THAT TOPS THE RIDGE INTO THE AREA. AGAIN RELATIVELY DRY AIR
FEEDING IN FROM THE EAST SHOULD RESULT IN THE MCS STRATIFYING OUT AS
IT REACHES THE AREA. ANY THUNDER WOULD BE ISOLATED AND ACROSS THE
SOUTH THIRD AT MOST.
SUNDAY ON...
THE MODEL CONSENSUS CONTINUES AN ACTIVE WEATHER PATTERN ACROSS THE
MIDWEST WITH NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE OVER THE
AREA. THE OVERALL SET UP IS COMPARABLE TO A MID SUMMER RING OF FIRE.
THUS MCS EVENTS ARE EXPECTED TO DEVELOP AND MOVE INTO THE AREA AT
NIGHT WITH THE MCS DECAYING ACROSS THE AREA DURING THE DAY TIME.
BOUNDARIES LEFT OVER FROM EACH MCS EVENT WILL PROVIDE THE FOCUS FOR
DIURNAL CONVECTION DURING THE AFTERNOON AND EVENING.
THE MODEL CONSENSUS HAS CHC POPS FROM SUNDAY THROUGH WEDNESDAY
REFLECTING THIS SCENARIO. THERE WILL BE PERIODS OF DRY WX BUT THEY
CANNOT BE RESOLVED DUE TO SMOOTHING OF THE MODEL FEATURES.
TEMPERATURES WILL REMAIN BELOW NORMAL ON SUNDAY FOLLOWED BY
MODERATING TEMPERATURES MONDAY THROUGH WEDNESDAY.
08
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 253 AM CDT THU MAY 23 2013
DEFORMATION ZONE WITH A SWATH OF MOSTLY IFR CONDITIONS AND AREAS
OF RAIN/DRIZZLE WILL SLIDE SOUTHEAST OF AREA BETWEEN 11-14Z AT ALL
TERMINALS. CLOUDS WILL LIFT TO MVFR CONDITIONS AND THEN CLEAR FROM
NORTH TO SOUTH BETWEEN 15-20Z. NORTHERLY WINDS OF 10 TO 20 KTS
WILL DIMINISH AROUND SUNSET AND BECOME LIGHT AFTER 05Z AS SURFACE
HIGH MOVES OVERHEAD.
NICHOLS
&&
.CLIMATE...
ISSUED AT 253 AM CDT THU MAY 23 2013
RECORD LOWS FOR MAY 24...
MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...NICHOLS
CLIMATE...NICHOLS
000
FXUS63 KDVN 222343
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
643 PM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 246 PM CDT WED MAY 22 2013
LATEST SFC ANALYSIS WAS INDICATING AN OCCLUDED LOW JUST WEST OF
MKE WI...WITH SECONDARY FEATURE DRAPING BACK TOWARD WATERLOO. SFC
PRESSURE RISES INCREASING ACRS NORTHWESTERN IA...WITH A FALLS MAX
PUSHING ACRS THE HEART OF THE GRT LKS. ALOFT...WATER VAPOR LOOP
WAS INDICATING CLOSE UPPER LOW ACRS NORTH CENTRAL IA ATTM WITH A
SLOW GYRATION TO THE EAST-SOUTHEAST AND WANTING TO OPEN UP. LLVL
COLD CONVEYOR EVIDENT ON WESTERN FLANK OF THIS FEATURE WITH TEMPS
IN THE 50S ACRS MUCH OF THE WESTERN HALF OF IA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 246 PM CDT WED MAY 22 2013
TONIGHT...EXPECT SCTRD SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM
TO INCREASE FROM THE WEST THROUGH EARLY EVENING...BUT SHOWERS TO
NOT BECOME MORE WIDESPREAD ACRS THE NORTHERN/NORTHWESTERN THIRD OF
THE DVN CWA OUT OF MN/WI NOT TIL AFTER 03Z AS UPPER LEVEL WAVE
PIVOTS AROUND THE PARENT TROF AND THEN DOWN ACRS THE CWA AS THE
NIGHT PROGRESSES. FORCING AND COLUMN SATURATION SUGGEST A FEW
AREAS NORTH OF I80 MAY GET UP TO 0.15 OF AN INCH OF RAINFALL BY
12Z THU...OTHERWISE THE MAJORITY OF AREAS TO RECEIVE UNDER A
TENTH. TOP-DOWN DRYING FROM THE NORTHWEST NOT AS AGGRESSIVE LOOKING
ON CURRENT 12Z FCST SOUNDING PROGS AS YESTERDAY AT THIS
TIME...THUS WILL KEEP ALL SHOWER WORDING OR A HYBRID OF SHOWER-
LIGHT RAIN LATE TONIGHT AS OPPOSED TO DRIZZLE. BUT THERE MAY STILL
BE LIGHT PRECIP SIMILAR TO DRIZZLE OR SPRINKLES ALONG HWY 20
TOWARD DAYBREAK. LOWS IN THE UPPER 40S TO LOWER 50S IN THE
NORTHWESTERN THIRD...TO THE MID 50S IN THE SOUTHEAST.
THURSDAY...AS UPPER WAVE PASSES OFF TO THE SOUTHEAST AND TOP-DOWN
COLUMN DRYING REALLY TAKES GRIP OF THE REGION...LINGERING LIGHT
RAIN/SHOWERS TO PUSH OFF TO THE SOUTHEAST/DECAY AS WELL BY LATE
MORNING...WITH CLOUDS CLEARING FROM NORTH TO SOUTH DURING MIDDAY AND
IN THE AFTERNOON. SEASONABLY IMPRESSIVE CANADIAN BACK DOOR HIGH TO
DUMP DOWN THE WESTERN GRT LKS AND UPPER MS RVR VALLEY THU
AFTERNOON...WITH INCOMING GRADIENT AND MIXING CAUSING VEERING WIND
PROFILES TO THE NORTH-NORTHEAST TO MIX TO 10 TO 20 MPH DURING
MIDDAY AND MUCH OF THE AFTERNOON BEFORE WIND DROP OFF AND DECOUPLE
COMMENCES TOWARD THU EVENING. SOME HIGHER GUSTS MAY BE POSSIBLE
THU AFTERNOON AS WELL. INCOMING COOL AIR MASS SUPPORTS HIGHS ONLY
IN THE LOW TO MID 60S FOR THU...BUT EXPECT AFTERNOON INSOLATION
AND DEEPER MIXING TO PRODUCE SOME UPPER 60S OR EVEN A 70 IN A FEW
SPOTS. ..12..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 246 PM CDT WED MAY 22 2013
THE EXTENDED PERIOD WILL BEGIN WITH A BENIGN AND COOL PATTERN...AND
TRANSITION TO AN ACTIVE AND GRADUALLY WARMER WEATHER REGIME FROM THE
WEEKEND THROUGH NEXT WEDNESDAY. HIGH PRESSURE WILL CONTINUE TO BUILD
IN THURSDAY NIGHT...WITH CLEAR SKIES AND LIGHT WINDS. THIS WILL
PROVIDE AN EXCELLENT RADIATIONAL COOLING NIGHT...AND LOWS IN THE
UPPER 30S NORTHEAST TO LOWER 40S CENTRAL AND SOUTHWEST ARE WELL
JUSTIFIED BY MODEL DATA AND ANALYSIS.
THIS COOL HIGH PRESSURE REMAINS OVER THE MIDWEST FRIDAY...AND THIS
SHOULD PROVIDE A STELLAR FRIDAY. COOL AIR ALOFT...LIGHT WINDS...AND
SUNSHINE IS EXPECTED...THUS THE INTENSE SUNSHINE OF LATE MAY SHOULD
STRUGGLE TO BOOST TEMPERATURES THROUGH THE MID TO UPPER 60S.
FRIDAY NIGHT THROUGH THE WEEKEND...THERE ARE POSITIONAL DIFFERENCES
IN THE ELEVATED BOUNDARY PLACEMENT BETWEEN THE SOUTHERN ECMWF...AND
THE MORE NORTHERLY GFS/CANADIAN/NAM. THIS SEEMS TO STEM FROM HOW
THE ECMWF DIFFERS IN HANDLING HOW MUCH ENERGY IS SPINNING AROUND THE
EAST COAST LOW PRESSURE. IN THE WAKE OF THE SUPER ENERGETIC EAST
COAST LOW...HIGH PRESSURE IS STRONGER IN THE UPPER MIDWEST. THUS...A
MORE SOUTHERLY BOUNDARY PLACEMENT. SO IT BECOMES A QUESTION ON HOW
MUCH RAIN POTENTIAL WE HAVE...MAY BE ANSWERED MORE DIRECTLY BY
FINDING HOW MUCH OF A HANDLE MODELS HAVE ON THE EVOLUTION OF THE
EAST COAST LOW PRESSURE. TOSS IN THE LIKELIHOOD THAT MODELS ARE
OVERDONE INITIALLY ON MOISTURE IN THE PLAINS DUE TO LOWER THAN
NORMAL CROP PROGRESS...AND IT SEEMS TO ME WE HAVE LESS CAPE AT LOW
LEVELS THAN ANY MODEL SUGGESTS TO OUR SOUTH...AND THERE IS GOOD
POTENTIAL FOR A DOMINANCE OF ELEVATED SHOWERS AND STORMS. THUS...A
SOLID MODERATE TO HIGH CHANCE FOR SHOWERS AND ELEVATED STORMS
THROUGHOUT IOWA AND ILLINOIS FRIDAY NIGHT AFTER MIDNIGHT INTO AT
LEAST TUESDAY MORNING. WILL KEEP POPS MAINLY BELOW LIKELY RANGES AT
THIS POINT DUE TO THE AFOREMENTIONED UNCERTAINTIES.
LOOKING AT TEMPERATURES...WE SHOULD ONLY BE RESTRICTED TO THE 50S
SATURDAY AND SUNDAY IF IT IS A TOTAL WASHOUT. THIS SEEMS
UNLIKELY...AND WILL GO LOWER 60S TO MID 60S SATURDAY...AND MID 60S
TO AROUND 70S SOUTH SUNDAY. AFTER THIS...WILL SIDE CLOSER TO THE
MORE NORTHERLY GFS/GEM AND GO MILDER MONDAY THROUGH WEDNESDAY...WITH
HIGHS RISING THROUGH THE 70S TO NEAR 80 BY WEDNESDAY. LOWS WILL BE
MAINLY IN THE 60S.
ERVIN
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 637 PM CDT WED MAY 22 2013
LOW PRESSURE SYSTEM OVER SOUTHERN WISCONSIN HAS SPREAD LOW END VFR
TO MVFR CLOUDS OVER THE TERMINALS WITH SCATTERED SHOWERS WITH MVFR
VSBYS IN LIGHT RAIN. EXPECT THESE SCATTERED SHOWERS TO DIMINISH IN
COVERAGE AND SHOULD BE GONE BY 02Z. HOWEVER...A MAIN BAND OF LIGHT
RAIN WILL ROTATE ACROSS THE AREA BETWEEN 05Z AND 15Z WITH A BAND
OF WIDESPREAD IFR CIGS AND VSBYS. AFTER 15Z WE SHOULD RETURN TO
MVFR CIGS AND VFR VSBYS AS THE LIGHT RAIN MOVES OUT OF THE AREA TO
THE SOUTH. AFTER 05Z TONIGHT WINDS TO INCREASE OUT OF THE NORTH
SUSTAINED SPEEDS AROUND 15KTS AND GUSTS TO 20KTS...CONTINUING
UNTIL ABOUT 15Z BEFORE FALLING OFF THURSDAY AFTERNOON. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...LE
000
FXUS63 KDVN 222013
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
313 PM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 246 PM CDT WED MAY 22 2013
LATEST SFC ANALYSIS WAS INDICATING AN OCCLUDED LOW JUST WEST OF
MKE WI...WITH SECONDARY FEATURE DRAPING BACK TOWARD WATERLOO. SFC
PRESSURE RISES INCREASING ACRS NORTHWESTERN IA...WITH A FALLS MAX
PUSHING ACRS THE HEART OF THE GRT LKS. ALOFT...WATER VAPOR LOOP
WAS INDICATING CLOSE UPPER LOW ACRS NORTH CENTRAL IA ATTM WITH A
SLOW GYRATION TO THE EAST-SOUTHEAST AND WANTING TO OPEN UP. LLVL
COLD CONVEYOR EVIDENT ON WESTERN FLANK OF THIS FEATURE WITH TEMPS
IN THE 50S ACRS MUCH OF THE WESTERN HALF OF IA.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 246 PM CDT WED MAY 22 2013
TONIGHT...EXPECT SCTRD SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM
TO INCREASE FROM THE WEST THROUGH EARLY EVENING...BUT SHOWERS TO
NOT BECOME MORE WIDESPREAD ACRS THE NORTHERN/NORTHWESTERN THIRD OF
THE DVN CWA OUT OF MN/WI NOT TIL AFTER 03Z AS UPPER LEVEL WAVE
PIVOTS AROUND THE PARENT TROF AND THEN DOWN ACRS THE CWA AS THE
NIGHT PROGRESSES. FORCING AND COLUMN SATURATION SUGGEST A FEW
AREAS NORTH OF I80 MAY GET UP TO 0.15 OF AN INCH OF RAINFALL BY
12Z THU...OTHERWISE THE MAJORITY OF AREAS TO RECEIVE UNDER A
TENTH. TOP-DOWN DRYING FROM THE NORTHWEST NOT AS AGGRESSIVE LOOKING
ON CURRENT 12Z FCST SOUNDING PROGS AS YESTERDAY AT THIS
TIME...THUS WILL KEEP ALL SHOWER WORDING OR A HYBRID OF SHOWER-
LIGHT RAIN LATE TONIGHT AS OPPOSED TO DRIZZLE. BUT THERE MAY STILL
BE LIGHT PRECIP SIMILAR TO DRIZZLE OR SPRINKLES ALONG HWY 20
TOWARD DAYBREAK. LOWS IN THE UPPER 40S TO LOWER 50S IN THE
NORTHWESTERN THIRD...TO THE MID 50S IN THE SOUTHEAST.
THURSDAY...AS UPPER WAVE PASSES OFF TO THE SOUTHEAST AND TOP-DOWN
COLUMN DRYING REALLY TAKES GRIP OF THE REGION...LINGERING LIGHT
RAIN/SHOWERS TO PUSH OFF TO THE SOUTHEAST/DECAY AS WELL BY LATE
MORNING...WITH CLOUDS CLEARING FROM NORTH TO SOUTH DURING MIDDAY AND
IN THE AFTERNOON. SEASONABLY IMPRESSIVE CANADIAN BACK DOOR HIGH TO
DUMP DOWN THE WESTERN GRT LKS AND UPPER MS RVR VALLEY THU
AFTERNOON...WITH INCOMING GRADIENT AND MIXING CAUSING VEERING WIND
PROFILES TO THE NORTH-NORTHEAST TO MIX TO 10 TO 20 MPH DURING
MIDDAY AND MUCH OF THE AFTERNOON BEFORE WIND DROP OFF AND DECOUPLE
COMMENCES TOWARD THU EVENING. SOME HIGHER GUSTS MAY BE POSSIBLE
THU AFTERNOON AS WELL. INCOMING COOL AIR MASS SUPPORTS HIGHS ONLY
IN THE LOW TO MID 60S FOR THU...BUT EXPECT AFTERNOON INSOLATION
AND DEEPER MIXING TO PRODUCE SOME UPPER 60S OR EVEN A 70 IN A FEW
SPOTS. ..12..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 246 PM CDT WED MAY 22 2013
THE EXTENDED PERIOD WILL BEGIN WITH A BENIGN AND COOL PATTERN...AND
TRANSITION TO AN ACTIVE AND GRADUALLY WARMER WEATHER REGIME FROM THE
WEEKEND THROUGH NEXT WEDNESDAY. HIGH PRESSURE WILL CONTINUE TO BUILD
IN THURSDAY NIGHT...WITH CLEAR SKIES AND LIGHT WINDS. THIS WILL
PROVIDE AN EXCELLENT RADIATIONAL COOLING NIGHT...AND LOWS IN THE
UPPER 30S NORTHEAST TO LOWER 40S CENTRAL AND SOUTHWEST ARE WELL
JUSTIFIED BY MODEL DATA AND ANALYSIS.
THIS COOL HIGH PRESSURE REMAINS OVER THE MIDWEST FRIDAY...AND THIS
SHOULD PROVIDE A STELLAR FRIDAY. COOL AIR ALOFT...LIGHT WINDS...AND
SUNSHINE IS EXPECTED...THUS THE INTENSE SUNSHINE OF LATE MAY SHOULD
STRUGGLE TO BOOST TEMPERATURES THROUGH THE MID TO UPPER 60S.
FRIDAY NIGHT THROUGH THE WEEKEND...THERE ARE POSITIONAL DIFFERENCES
IN THE ELEVATED BOUNDARY PLACEMENT BETWEEN THE SOUTHERN ECMWF...AND
THE MORE NORTHERLY GFS/CANADIAN/NAM. THIS SEEMS TO STEM FROM HOW
THE ECMWF DIFFERS IN HANDLING HOW MUCH ENERGY IS SPINNING AROUND THE
EAST COAST LOW PRESSURE. IN THE WAKE OF THE SUPER ENERGETIC EAST
COAST LOW...HIGH PRESSURE IS STRONGER IN THE UPPER MIDWEST. THUS...A
MORE SOUTHERLY BOUNDARY PLACEMENT. SO IT BECOMES A QUESTION ON HOW
MUCH RAIN POTENTIAL WE HAVE...MAY BE ANSWERED MORE DIRECTLY BY
FINDING HOW MUCH OF A HANDLE MODELS HAVE ON THE EVOLUTION OF THE
EAST COAST LOW PRESSURE. TOSS IN THE LIKELIHOOD THAT MODELS ARE
OVERDONE INITIALLY ON MOISTURE IN THE PLAINS DUE TO LOWER THAN
NORMAL CROP PROGRESS...AND IT SEEMS TO ME WE HAVE LESS CAPE AT LOW
LEVELS THAN ANY MODEL SUGGESTS TO OUR SOUTH...AND THERE IS GOOD
POTENTIAL FOR A DOMINANCE OF ELEVATED SHOWERS AND STORMS. THUS...A
SOLID MODERATE TO HIGH CHANCE FOR SHOWERS AND ELEVATED STORMS
THROUGHOUT IOWA AND ILLINOIS FRIDAY NIGHT AFTER MIDNIGHT INTO AT
LEAST TUESDAY MORNING. WILL KEEP POPS MAINLY BELOW LIKELY RANGES AT
THIS POINT DUE TO THE AFOREMENTIONED UNCERTAINTIES.
LOOKING AT TEMPERATURES...WE SHOULD ONLY BE RESTRICTED TO THE 50S
SATURDAY AND SUNDAY IF IT IS A TOTAL WASHOUT. THIS SEEMS
UNLIKELY...AND WILL GO LOWER 60S TO MID 60S SATURDAY...AND MID 60S
TO AROUND 70S SOUTH SUNDAY. AFTER THIS...WILL SIDE CLOSER TO THE
MORE NORTHERLY GFS/GEM AND GO MILDER MONDAY THROUGH WEDNESDAY...WITH
HIGHS RISING THROUGH THE 70S TO NEAR 80 BY WEDNESDAY. LOWS WILL BE
MAINLY IN THE 60S.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1236 PM CDT WED MAY 22 2013
WRAP AROUND LOW VFR TO MVFR CLOUD DECK TO CONTINUE ACRS ALL TAF
SITES THIS AFTERNOON...WITH SCTRD SHOWERS STILL YET POSSIBLY TO POP
UP. OTHER SHOWERS ALREADY DEVELOPED IN CENTRAL IA WILL TRY TO
ROTATE THIS WAY AROUND MID/UPPER LOW PRESSURE CIRCULATION OVER THE
NORTH CENTRAL IA/MN BORDER REGION. THE CLOUD DECK MAY BECOME MORE
WIDESPREAD LOWER MVFR TONIGHT...WITH AREAS OF SHOWERS OR RAIN
BECOMING MORE WIDESPREAD AS WELL IN THE VCNTY OF CID AND DBQ
AROUND MIDNIGHT AS THEY PIVOT SOUTHEAST AROUND MID LEVEL CIRCULATION.
THIS ACTIVITY THEN MOVING TOWARD MLI AND BRL THROUGH THU MORNING. SOME
IFR DECKS POSSIBLE AFTER 02Z TONIGHT IN VCNTY OF ALL TERMINALS...
WITH 3-5SM FOG AND MIST WHERE THE RAIN LETS UP. GENERALLY A WEST
WIND THOUGH THIS EVENING BEFORE IT VEERS TO THE NORTH AS THE
OVERNIGHT PROGRESSES. NORTHEAST WINDS INCREASING TO 10-20 KTS BY
LATE THU MORNING AND PASSAGE OF UPPER LOW ACRS THE GRT LKS SHOULD
HELP CONDITIONS IMPROVE LATE MORNING INTO THE AFTERNOON. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...ERVIN
AVIATION...12
000
FXUS63 KDVN 221752
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1252 PM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 252 AM CDT WED MAY 22 2013
LARGE AND QUITE SEASONABLY COOL UPPER LOW PRESSURE SYSTEM OVER
WESTERN PORTIONS OF MIDWEST TO PIN WHEEL OVER FORECAST AREA NEXT
24 HOURS. DEEP OCCLUDED SYSTEM IDEAL FOR LARGE AREAS OF CLOUDS
AND LIGHT SHOWERS AND POTENTIALLY AREAS OF DRIZZLE TONIGHT IN COOL
CONVEYOR BELT NORTH SIDE OF SYSTEM. VERIFICATION AT 06Z AND 08Z
SUGGESTS COOL AIR NEAR SURFACE MOVING INTO AREA A BIT FASTER THAN
MOST SOLUTIONS FROM THE NORTHWEST. UPSTREAM ENERGY SUPPORTS BELOW
NORMAL TEMPS THEN RETURN TO ZONAL FLOW AND UNSETTLED AND STILL COOL
FOR DAYS 4-7.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT WED MAY 22 2013
TODAY...LOTS OF CLOUDS WITH A FEW BRIEF PERIODS OF SUN MOSTLY ALONG
MISSISSIPPI RIVER INTO EARLY AFTERNOON. NOWCAST TOOLS SUPPORT VORT
MAX OVER SW MISSOURI TO ROTATE OVER AREA AND WITH HEATING AND
FORCING PRODUCING SCATTERED TO AREAS OF SHOWERS TODAY. HIGHS WILL
BE A CHALLENGE BASED ON CLOUD COVER WITH DEEP CLOUDS WEST OF I-380
CORRIDOR AND HIGHWAY 218. HENCE...LOWER 60S WEST TO AROUND 70
ALONG AND EAST OF THE MISSISSIPPI RIVER. SAME CONCERN AS YESTERDAY
WITH COOL AIR AS IF MOVES IN FASTER...AS WHAT HAPPENED YESTERDAY
WITH CLOUDS...HIGH MAY NEED TRIMMING BY AT LEAST A COUPLE DEGREES
FOR LATER SHIFTS. ANY PRECIPITATION THAT FALLS SHOULD BE LESS THAN
A TENTH OF AN INCH.
TONIGHT...UPPER OCCLUSION TO MOVE SOUTHEAST WITH NORTH WINDS ARRIVING
OVER AT LEAST NORTH 1/2 BY MORNING. LOW LEVEL PROFILES AND FORCING
ARE SUPPORTIVE OF WIDESPREAD LIGHT RAIN AND DRIZZLE FOR LATER SHIFTS
NORTH OF UPPER OCCLUSION. MINS IN THE UPPER 40S SUGGESTED NORTH DUE
TO EVAPORATIVE COOLING WITH NORTH WINDS OF 10-20 MPH. QUITE COOL FOR
LATE MAY. SOUTH SECTION LESS CHANCE OF LIGHT RAIN AND DRIZZLE WITH
LOWER POPS. ADDITIONAL RAIN TOTALS AGAIN LIKELY BELOW TO WELL BELOW
A TENTH OF AN INCH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 252 AM CDT WED MAY 22 2013
SHOWERS WILL LINGER ACROSS MOST OF THE AREA THURSDAY MORNING AS THE
UPPER LOW SLOWLY MOVES EAST INTO INDIANA. DRY CONDITIONS WITH A
CLEARING TREND IS EXPECTED DURING THE AFTERNOON. TEMPERATURES WILL
BE BELOW NORMAL.
THURS NIGHT/FRIDAY A VERY COOL CANADIAN HIGH PRESSURE WILL BUILD
INTO THE MIDWEST. LIGHT WINDS AND GENERALLY CLEAR SKIES WILL DROP
TEMPERATURES INTO THE 40S WITH UPPER 30S LIKELY IN THE FAVORED COLD
AREAS OF THE NORTHERN CWFA. TEMPERATURES ON FRIDAY WILL AVERAGE
BELOW NORMAL.
FRI NIGHT RETURN FLOW ALOFT DEVELOPS ACROSS THE AREA. INITIALLY THE
DRY AIR WILL WIN OUT AND KEEP PRECIPITATION WEST OF THE AREA. THE
MODELS MAY BE A BIT TOO QUICK WITH WAA PRECIPITATION ENTERING THE
CWFA DURING THE EVENING. THUS THE INTRODUCTION OF SHOWERS WILL BE
DELAYED UNTIL LATE EVENING OVER ROUGHLY THE WESTERN HALF OF THE
CWFA. AFTER MIDNIGHT ALL MODELS SHOW A RESPECTABLE THETA E GRADIENT
MOVING ACROSS THE AREA ALONG WITH CONTINUED FLOW OFF LAKE MICHIGAN
IN THE LOW LEVELS.
THESE FEATURES COMBINED WITH THE RETURN FLOW ALOFT WILL CREATE AN
EFFECTIVE BOUNDARY TO ALLOW PRECIPITATION TO DEVELOP/MOVE INTO THE
CWFA. ALTHOUGH THE AMOUNT OF INSTABILITY IS IN QUESTION...THUNDER
WAS KEPT AFTER MIDNIGHT DUE TO THE THETA E GRADIENT.
SATURDAY ON...
THE EFFECTIVE BOUNDARY CREATED BY FLOW OFF LAKE MICHIGAN WILL REMAIN
OVER OR NEAR THE CWFA SATURDAY THROUGH TUESDAY. THE INCREASED
CONVERGENCE AND STRONGER THERMAL GRADIENT FROM THIS BOUNDARY WILL
HELP ENHANCE PRECIPITATION WITH EACH DISTURBANCE COMING OUT OF THE
PLAINS.
THE MODEL CONSENSUS HAS MAINLY CHC POPS FROM SATURDAY THROUGH
TUESDAY ACROSS THE AREA. THERE WILL LIKELY BE PERIODS OF DRY WX FROM
SATURDAY THROUGH TUESDAY. HOWEVER...SMOOTHING OF MODEL FEATURES AND
DISAGREEMENT ON TIMING/PLACEMENT OF SIGNIFICANT FEATURES PRECLUDES
INCLUDING DRY PERIODS IN THE FCST RIGHT NOW. TEMPERATURES WILL
AVERAGE BELOW NORMAL OVER THE WEEKEND WITH MODERATING TEMPERATURES
EARLY NEXT WEEK.
08
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1236 PM CDT WED MAY 22 2013
WRAP AROUND LOW VFR TO MVFR CLOUD DECK TO CONTINUE ACRS ALL TAF
SITES THIS AFTERNOON...WITH SCTRD SHOWERS STILL YET POSSIBLY TO POP
UP. OTHER SHOWERS ALREADY DEVELOPED IN CENTRAL IA WILL TRY TO
ROTATE THIS WAY AROUND MID/UPPER LOW PRESSURE CIRCULATION OVER THE
NORTH CENTRAL IA/MN BORDER REGION. THE CLOUD DECK MAY BECOME MORE
WIDESPREAD LOWER MVFR TONIGHT...WITH AREAS OF SHOWERS OR RAIN
BECOMING MORE WIDESPREAD AS WELL IN THE VCNTY OF CID AND DBQ
AROUND MIDNIGHT AS THEY PIVOT SOUTHEAST AROUND MID LEVEL CIRCULATION.
THIS ACTIVITY THEN MOVING TOWARD MLI AND BRL THROUGH THU MORNING. SOME
IFR DECKS POSSIBLE AFTER 02Z TONIGHT IN VCNTY OF ALL TERMINALS...
WITH 3-5SM FOG AND MIST WHERE THE RAIN LETS UP. GENERALLY A WEST
WIND THOUGH THIS EVENING BEFORE IT VEERS TO THE NORTH AS THE
OVERNIGHT PROGRESSES. NORTHEAST WINDS INCREASING TO 10-20 KTS BY
LATE THU MORNING AND PASSAGE OF UPPER LOW ACRS THE GRT LKS SHOULD
HELP CONDITIONS IMPROVE LATE MORNING INTO THE AFTERNOON. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...12
000
FXUS63 KDVN 221139
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
639 AM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 252 AM CDT WED MAY 22 2013
LARGE AND QUITE SEASONABLY COOL UPPER LOW PRESSURE SYSTEM OVER
WESTERN PORTIONS OF MIDWEST TO PIN WHEEL OVER FORECAST AREA NEXT
24 HOURS. DEEP OCCLUDED SYSTEM IDEAL FOR LARGE AREAS OF CLOUDS
AND LIGHT SHOWERS AND POTENTIALLY AREAS OF DRIZZLE TONIGHT IN COOL
CONVEYOR BELT NORTH SIDE OF SYSTEM. VERIFICATION AT 06Z AND 08Z
SUGGESTS COOL AIR NEAR SURFACE MOVING INTO AREA A BIT FASTER THAN
MOST SOLUTIONS FROM THE NORTHWEST. UPSTREAM ENERGY SUPPORTS BELOW
NORMAL TEMPS THEN RETURN TO ZONAL FLOW AND UNSETTLED AND STILL COOL
FOR DAYS 4-7.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT WED MAY 22 2013
TODAY...LOTS OF CLOUDS WITH A FEW BRIEF PERIODS OF SUN MOSTLY ALONG
MISSISSIPPI RIVER INTO EARLY AFTERNOON. NOWCAST TOOLS SUPPORT VORT
MAX OVER SW MISSOURI TO ROTATE OVER AREA AND WITH HEATING AND
FORCING PRODUCING SCATTERED TO AREAS OF SHOWERS TODAY. HIGHS WILL
BE A CHALLENGE BASED ON CLOUD COVER WITH DEEP CLOUDS WEST OF I-380
CORRIDOR AND HIGHWAY 218. HENCE...LOWER 60S WEST TO AROUND 70
ALONG AND EAST OF THE MISSISSIPPI RIVER. SAME CONCERN AS YESTERDAY
WITH COOL AIR AS IF MOVES IN FASTER...AS WHAT HAPPENED YESTERDAY
WITH CLOUDS...HIGH MAY NEED TRIMMING BY AT LEAST A COUPLE DEGREES
FOR LATER SHIFTS. ANY PRECIPITATION THAT FALLS SHOULD BE LESS THAN
A TENTH OF AN INCH.
TONIGHT...UPPER OCCLUSION TO MOVE SOUTHEAST WITH NORTH WINDS ARRIVING
OVER AT LEAST NORTH 1/2 BY MORNING. LOW LEVEL PROFILES AND FORCING
ARE SUPPORTIVE OF WIDESPREAD LIGHT RAIN AND DRIZZLE FOR LATER SHIFTS
NORTH OF UPPER OCCLUSION. MINS IN THE UPPER 40S SUGGESTED NORTH DUE
TO EVAPORATIVE COOLING WITH NORTH WINDS OF 10-20 MPH. QUITE COOL FOR
LATE MAY. SOUTH SECTION LESS CHANCE OF LIGHT RAIN AND DRIZZLE WITH
LOWER POPS. ADDITIONAL RAIN TOTALS AGAIN LIKELY BELOW TO WELL BELOW
A TENTH OF AN INCH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 252 AM CDT WED MAY 22 2013
SHOWERS WILL LINGER ACROSS MOST OF THE AREA THURSDAY MORNING AS THE
UPPER LOW SLOWLY MOVES EAST INTO INDIANA. DRY CONDITIONS WITH A
CLEARING TREND IS EXPECTED DURING THE AFTERNOON. TEMPERATURES WILL
BE BELOW NORMAL.
THURS NIGHT/FRIDAY A VERY COOL CANADIAN HIGH PRESSURE WILL BUILD
INTO THE MIDWEST. LIGHT WINDS AND GENERALLY CLEAR SKIES WILL DROP
TEMPERATURES INTO THE 40S WITH UPPER 30S LIKELY IN THE FAVORED COLD
AREAS OF THE NORTHERN CWFA. TEMPERATURES ON FRIDAY WILL AVERAGE
BELOW NORMAL.
FRI NIGHT RETURN FLOW ALOFT DEVELOPS ACROSS THE AREA. INITIALLY THE
DRY AIR WILL WIN OUT AND KEEP PRECIPITATION WEST OF THE AREA. THE
MODELS MAY BE A BIT TOO QUICK WITH WAA PRECIPITATION ENTERING THE
CWFA DURING THE EVENING. THUS THE INTRODUCTION OF SHOWERS WILL BE
DELAYED UNTIL LATE EVENING OVER ROUGHLY THE WESTERN HALF OF THE
CWFA. AFTER MIDNIGHT ALL MODELS SHOW A RESPECTABLE THETA E GRADIENT
MOVING ACROSS THE AREA ALONG WITH CONTINUED FLOW OFF LAKE MICHIGAN
IN THE LOW LEVELS.
THESE FEATURES COMBINED WITH THE RETURN FLOW ALOFT WILL CREATE AN
EFFECTIVE BOUNDARY TO ALLOW PRECIPITATION TO DEVELOP/MOVE INTO THE
CWFA. ALTHOUGH THE AMOUNT OF INSTABILITY IS IN QUESTION...THUNDER
WAS KEPT AFTER MIDNIGHT DUE TO THE THETA E GRADIENT.
SATURDAY ON...
THE EFFECTIVE BOUNDARY CREATED BY FLOW OFF LAKE MICHIGAN WILL REMAIN
OVER OR NEAR THE CWFA SATURDAY THROUGH TUESDAY. THE INCREASED
CONVERGENCE AND STRONGER THERMAL GRADIENT FROM THIS BOUNDARY WILL
HELP ENHANCE PRECIPITATION WITH EACH DISTURBANCE COMING OUT OF THE
PLAINS.
THE MODEL CONSENSUS HAS MAINLY CHC POPS FROM SATURDAY THROUGH
TUESDAY ACROSS THE AREA. THERE WILL LIKELY BE PERIODS OF DRY WX FROM
SATURDAY THROUGH TUESDAY. HOWEVER...SMOOTHING OF MODEL FEATURES AND
DISAGREEMENT ON TIMING/PLACEMENT OF SIGNIFICANT FEATURES PRECLUDES
INCLUDING DRY PERIODS IN THE FCST RIGHT NOW. TEMPERATURES WILL
AVERAGE BELOW NORMAL OVER THE WEEKEND WITH MODERATING TEMPERATURES
EARLY NEXT WEEK.
08
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 637 AM CDT WED MAY 22 2013
DEEPLY OCCLUDED LOW PRESSURE SYSTEM TO MOVE SOUTHEAST ACROSS AREA
NEXT 24 TO 30 HOURS. CLOUDS WILL BE ON THE INCREASE WITH LOWERING
CEILING AND SCATTERED LIGHT RAIN SHOWERS TODAY INTO THIS EVENING.
CIGS AOA 5K AGL WILL THICKEN AND LOWER TO 1-3K AGL FROM WEST TO
EAST BETWEEN 21-09Z. VISIBILITIES WILL STAY ABOVE 4 MILES WITH ANY
SHOWERS UNTIL AFTER 06Z. THEN...DBQ...CID...MLI TERMINALS MAY APPROACH
IFR CONDITIONS BY 12Z WITH CIGS 500-1000 FT AGL AND VISIBILITIES
FALLING AT TIMES TO 1-3 MILES IN LIGHT RAIN AND DRIZZLE.
NICHOLS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...NICHOLS
000
FXUS63 KDVN 220814
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
314 AM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 252 AM CDT WED MAY 22 2013
LARGE AND QUITE SEASONABLY COOL UPPER LOW PRESSURE SYSTEM OVER
WESTERN PORTIONS OF MIDWEST TO PIN WHEEL OVER FORECAST AREA NEXT
24 HOURS. DEEP OCCLUDED SYSTEM IDEAL FOR LARGE AREAS OF CLOUDS
AND LIGHT SHOWERS AND POTENTIALLY AREAS OF DRIZZLE TONIGHT IN COOL
CONVEYOR BELT NORTH SIDE OF SYSTEM. VERIFICATION AT 06Z AND 08Z
SUGGESTS COOL AIR NEAR SURFACE MOVING INTO AREA A BIT FASTER THAN
MOST SOLUTIONS FROM THE NORTHWEST. UPSTREAM ENERGY SUPPORTS BELOW
NORMAL TEMPS THEN RETURN TO ZONAL FLOW AND UNSETTLED AND STILL COOL
FOR DAYS 4-7.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT WED MAY 22 2013
TODAY...LOTS OF CLOUDS WITH A FEW BRIEF PERIODS OF SUN MOSTLY ALONG
MISSISSIPPI RIVER INTO EARLY AFTERNOON. NOWCAST TOOLS SUPPORT VORT
MAX OVER SW MISSOURI TO ROTATE OVER AREA AND WITH HEATING AND
FORCING PRODUCING SCATTERED TO AREAS OF SHOWERS TODAY. HIGHS WILL
BE A CHALLENGE BASED ON CLOUD COVER WITH DEEP CLOUDS WEST OF I-380
CORRIDOR AND HIGHWAY 218. HENCE...LOWER 60S WEST TO AROUND 70
ALONG AND EAST OF THE MISSISSIPPI RIVER. SAME CONCERN AS YESTERDAY
WITH COOL AIR AS IF MOVES IN FASTER...AS WHAT HAPPENED YESTERDAY
WITH CLOUDS...HIGH MAY NEED TRIMMING BY AT LEAST A COUPLE DEGREES
FOR LATER SHIFTS. ANY PRECIPITATION THAT FALLS SHOULD BE LESS THAN
A TENTH OF AN INCH.
TONIGHT...UPPER OCCLUSION TO MOVE SOUTHEAST WITH NORTH WINDS ARRIVING
OVER AT LEAST NORTH 1/2 BY MORNING. LOW LEVEL PROFILES AND FORCING
ARE SUPPORTIVE OF WIDESPREAD LIGHT RAIN AND DRIZZLE FOR LATER SHIFTS
NORTH OF UPPER OCCLUSION. MINS IN THE UPPER 40S SUGGESTED NORTH DUE
TO EVAPORATIVE COOLING WITH NORTH WINDS OF 10-20 MPH. QUITE COOL FOR
LATE MAY. SOUTH SECTION LESS CHANCE OF LIGHT RAIN AND DRIZZLE WITH
LOWER POPS. ADDITIONAL RAIN TOTALS AGAIN LIKELY BELOW TO WELL BELOW
A TENTH OF AN INCH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 252 AM CDT WED MAY 22 2013
SHOWERS WILL LINGER ACROSS MOST OF THE AREA THURSDAY MORNING AS THE
UPPER LOW SLOWLY MOVES EAST INTO INDIANA. DRY CONDITIONS WITH A
CLEARING TREND IS EXPECTED DURING THE AFTERNOON. TEMPERATURES WILL
BE BELOW NORMAL.
THURS NIGHT/FRIDAY A VERY COOL CANADIAN HIGH PRESSURE WILL BUILD
INTO THE MIDWEST. LIGHT WINDS AND GENERALLY CLEAR SKIES WILL DROP
TEMPERATURES INTO THE 40S WITH UPPER 30S LIKELY IN THE FAVORED COLD
AREAS OF THE NORTHERN CWFA. TEMPERATURES ON FRIDAY WILL AVERAGE
BELOW NORMAL.
FRI NIGHT RETURN FLOW ALOFT DEVELOPS ACROSS THE AREA. INITIALLY THE
DRY AIR WILL WIN OUT AND KEEP PRECIPITATION WEST OF THE AREA. THE
MODELS MAY BE A BIT TOO QUICK WITH WAA PRECIPITATION ENTERING THE
CWFA DURING THE EVENING. THUS THE INTRODUCTION OF SHOWERS WILL BE
DELAYED UNTIL LATE EVENING OVER ROUGHLY THE WESTERN HALF OF THE
CWFA. AFTER MIDNIGHT ALL MODELS SHOW A RESPECTABLE THETA E GRADIENT
MOVING ACROSS THE AREA ALONG WITH CONTINUED FLOW OFF LAKE MICHIGAN
IN THE LOW LEVELS.
THESE FEATURES COMBINED WITH THE RETURN FLOW ALOFT WILL CREATE AN
EFFECTIVE BOUNDARY TO ALLOW PRECIPITATION TO DEVELOP/MOVE INTO THE
CWFA. ALTHOUGH THE AMOUNT OF INSTABILITY IS IN QUESTION...THUNDER
WAS KEPT AFTER MIDNIGHT DUE TO THE THETA E GRADIENT.
SATURDAY ON...
THE EFFECTIVE BOUNDARY CREATED BY FLOW OFF LAKE MICHIGAN WILL REMAIN
OVER OR NEAR THE CWFA SATURDAY THROUGH TUESDAY. THE INCREASED
CONVERGENCE AND STRONGER THERMAL GRADIENT FROM THIS BOUNDARY WILL
HELP ENHANCE PRECIPITATION WITH EACH DISTURBANCE COMING OUT OF THE
PLAINS.
THE MODEL CONSENSUS HAS MAINLY CHC POPS FROM SATURDAY THROUGH
TUESDAY ACROSS THE AREA. THERE WILL LIKELY BE PERIODS OF DRY WX FROM
SATURDAY THROUGH TUESDAY. HOWEVER...SMOOTHING OF MODEL FEATURES AND
DISAGREEMENT ON TIMING/PLACEMENT OF SIGNIFICANT FEATURES PRECLUDES
INCLUDING DRY PERIODS IN THE FCST RIGHT NOW. TEMPERATURES WILL
AVERAGE BELOW NORMAL OVER THE WEEKEND WITH MODERATING TEMPERATURES
EARLY NEXT WEEK.
08
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 252 AM CDT WED MAY 22 2013
DEEPLY OCCLUDED LOW PRESSURE SYSTEM TO MOVE SOUTHEAST ACROSS AREA
NEXT 24 TO 36 HOURS. CLOUDS WILL BE ON THE INCREASE WITH LOWERING
CEILING AND SCATTERED LIGHT RAIN SHOWERS TODAY INTO THIS EVENING.
CIGS AOA 5K AGL WILL THICKEN AND LOWER TO 1-3K AGL FROM WEST TO
EAST BETWEEN 21-09Z. VISIBILITIES WILL STAY ABOVE 4 MILES WITH ANY
SHOWERS UNTIL AFTER 06Z. DBQ...CID...MLI TERMINALS MAY APPROACH
IFR CONDITIONS BY 12Z WITH CIGS 500-1000 FT AGL AND VISIBILITIES
FALLING AT TIMES TO 1-3 MILES IN LIGHT RAIN AND DRIZZLE.
NICHOLS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...NICHOLS
000
FXUS63 KDVN 220524
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1224 AM CDT WED MAY 22 2013
.SYNOPSIS...
ISSUED AT 240 PM CDT TUE MAY 21 2013
A CLOSED H5 LOW WAS LOCATED OVER SOUTHEASTERN SOUTH DAKOTA AND
SOUTHWESTERN MINNESOTA EARLY THIS AFTERNOON. AT THE SURFACE
ELONGATED LOW PRESSURE EXTENDED FROM SOUTHEAST SOUTH DAKOTA INTO
WISCONSIN WITH TWO CIRCULATION CENTERS LOCATED ON THE WESTERN AND
EASTERN PORTIONS OF THE TROF. A WEAK COLD FRONT OVER EASTERN
IOWA/NORTHWEST ILLINOIS THIS AFTERNOON ORIGINATED IN THE WISCONSIN
LOW WHILE A SECONDARY FRONT WAS JUST ENTERING NORTHWEST IOWA.
ANOTHER...STRONGER...CLOSED H5 LOW WAS JUST MOVING INTO THE
PACIFIC NORTHWEST AND SHOULD ACT AS A KICKER TO DISLODGE THE MID
WEST SYSTEM.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
THE SYSTEM OVER THE CENTRAL U.S. WILL STAY OVER MINNESOTA AND
SOUTH DAKOTA TONIGHT AND THEN DROP SOUTHEAST WEDNESDAY KEEPING THE
REGION IN COOL CYCLONIC FLOW THROUGH THE PERIOD.
WEAK CONVERGENCE ALONG THE MID MISSISSIPPI VALLEY COLD FRONT AND
MODEST CAPES AROUND 1000 J/KG WILL PROVIDE A CHANCE OF SOME
EVENING THUNDERSTORMS EAST OF THE MISSISSIPPI RIVER THIS EVENING. A
S/W OVER THE SOUTHERN PLAINS THIS AFTERNOON WILL LIFT NORTHEAST
TONIGHT SPREADING MORE SHOWERS INTO AREAS ALONG AND EAST OF THE
MISSISSIPPI RIVER LATE TONIGHT AND WEDNESDAY MORNING. WEDNESDAY
AFTERNOON...AS A WEAKENING SURFACE LOW MOVES SOUTHEAST THROUGH THE
REGION...WRAP AROUND SHOWERS WILL SPREAD OVER THE AREA WITH THE
BETTER CHANCES ALONG AND NORTH OF INTERSTATE 80. COOL AIR
ADVECTING IN TO THE REGION TONIGHT AND WEDNESDAY WILL BRING
TEMPERATURES IN THE 50S AND LOW 60S TONIGHT. WEDNESDAY WITH COOLER
AIR AND PLACE AND WIDESPREAD CLOUDS HIGHS WILL ONLY BE IN THE 60S
AND LOW 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
WEDNESDAY NIGHT AND THURSDAY...SHOWERS WILL LOOK TO PIVOT AROUND
WESTERN FLANK OF WESTERN GRT LKS TROF WED NIGHT AN MAY BE MORE
PREVALENT ALONG AND NORTH OF I80 FROM 00Z-06Z...AND THEN CONTINUE
TO ROTATE SOUTH AND EAST INTO THU MORNING. FCST SOUNDINGS SUGGEST
DEEPER SATURATED SOUNDINGS WED EVENING WITH PW/S PUSHING OVER AN
INCH...BUT FORCING AND INSTABILITY MARGINAL TO MAKE THE MOST OF THOSE
PROFILES. MOST AREAS TO GET 2 TENTHS OF AN INCH OR LESS BY THU
MORNING. WILL NOT MENTION ANY THUNDER THU EVENING WITH LIMITED
INSTABILITY PROFILES. TOP-DOWN SATURATION LATE WED NIGHT INTO THU
MORNING MAY TREND SHOWERS INTO MORE OF A DRIZZLE REGIME AFTER 3 AM
CDT. A COOL DAMP NIGHT WITH LOWS IN THE LOWER 50S WITH SOME UPPER
40S POSSIBLE. SECONDARY SATELLITE VORT SPOKE MAY KEEP SHOWERS
FESTERING ACRS THE SOUTHEASTERN HALF OF THE FCST AREA THU MORNING
BEFORE THAT ACTIVITY MOVES OUT OR DECAYS BY AFTERNOON. HIGHS HELD IN
THE 60S LATEST 12Z RUN MODELS IN GOOD AGREEMENT IN ADVERTISING
SEASONABLY STRONG BACKDOOR CANADIAN SFC HIGH DUMPING DOWN THE WESTERN
GRT LKS LATE THU AND THU NIGHT...WITH ASSOCIATED COOL PUSH AND CLOUD
CLEAR OFF SETTING THE STAGE FOR A CHILLY NIGHT THU NIGHT. CURRENTLY
PROGGED AIR MASS ADVECTING IN COULD SUPPORT WIDESPREAD LOWS BY FRI
MORNING IN THE LOWER 40S TO UPPER 30S...EXCEPT FOR MID 40S IN THE
SOUTHWESTERN CWA.
FRIDAY AND SATURDAY...AFTER COOL START TO THE DAY...FRI LOOKS TO BE
MAINLY SUNNY UNTIL SOME HIGH CLOUDS SPILL IN FROM THE WEST OFF
GATHERING CONVECTION IN RETURN FLOW ACRS THE PLAINS. WARM AIR
RETURN FLOW ALOFT ESPECIALLY AROUND THE H85 MB LAYER COULD LIMIT
MIXING DEPTH AND KEEP FRI HIGHS HELD IN THE MID 60S EVEN WITH A LOT
OF INSOLATION. FRI NIGHT SOLUTIONS START TO DIVERGE BETWEEN THE 12Z
GFS...THE ECMWF...UKMET AND GEM. THE ECMWF CONTINUES TO BE LESS
AMPLIFIED WITH MID CONUS UPPER RIDGING...ALLOWING MCS DEVELOPMENT
ACRS THE CENTRAL PLAINS TO LEE OF WESTERN CONUS TROFFINESS TO RIDGE-
RIDE AND PROPAGATE EASTWARD ALONG H85 MB BOUNDARY ACRS PORTIONS OR
ALL OF THE DVN CWA LATER FRI NIGHT AND INTO SAT MORNING. THE NEW 12Z
ECMWF FAVORS HEAVIER ELEVATED CONVECTION FED ON H85 THTA-E PLUME ACRS
THE SOUTHERN HALF TO THIRD OF THE DVN CWA FRI NIGHT..WHERE AREAS
COULD GET UP TO AN INCH OF RAINFALL BY SAT MORNING. THIS IN CONTRAST
TO THE MORE AMPLIFIED RIDGE AND FURTHER WE AXIS PLACEMENT OF THE
12Z GFS...WHICH KEEPS FRI NIGHT AND SAT MORNING BASICALLY DRY UNTIL
ELEVATED PRECIP SYSTEM MOVES IN FROM THE WEST BY LATE SAT AFTERNOON.
THE GFS THEN SUGGESTS LLJ AND WARM MOIST CONVEYOR INCREASING OFF THE
WESTERN GULF WILL FUEL A NOCTURNAL MCS TYPE FEATURE SAT NIGHT INTO
SUNDAY MORNING ACRS MOST OF THE LOCAL FCST AREA. THIS WHILE THE
CONSISTENT ECMWF IS FURTHER SOUTH WITH LLVL BAROCLINIC RIBBON LAY
OUT AS WELL AS SOUTHWESTERN GRT LKS LLVL RIDGE AND NORTHEAST BOUNDARY
LAYER PUSH KEEPING THE DVN CWA MAINLY DRY EXCEPT FOR SOME
OVERRUNNING SHOWERS ACRS THE FAR SOUTH SAT NIGHT. THE CANADIAN MORE
SIMILAR TO THE GFS FOR SAT NIGHT AND ADVERTISES UP TO 1.5 INCHES OF
RAIN ACRS THE HEART OF THE CWA BY 12Z SUNDAY. WITH UNCERTAINTIES...
WILL HAVE TO KEEP CHC POPS FOR ALMOST EVERY PERIOD WHICH WILL BE AN
UNFORTUNATE THEME THAT WILL LOOK TO REOCCUR THROUGH THE REST OF THE
LONG RANGE. BOUNDARY PLACEMENT...PRECIP EPISODES AND OUTFLOW/CLOUD
DEBRIS TO PLAY HAVOC WITH TEMP FCST/S THROUGH THE HOLIDAY WEEKEND.
SUNDAY THROUGH NEXT TUESDAY...AS STATED ABOVE...LARGE DIFFERENCES IN
MID CONUS RIDGE PLACEMENT OF THE MAIN AXIS AND AMPLIFICATION...AS
WELL AS NORTH-SOUTH LAY OUT DIFFERENCES OF WEST-TO-EAST ORIENTED LLVL
BOUNDARY OR H85 FRONT BETWEEN THE MEDIUM RANGE MODELS WILL AVERAGE
OUT TO DAILY CHC POPS THOUGH MOST OF THIS PERIOD. THE NEW EURO
CONTINUES TO BE FURTHER SOUTH WITH THE QUASI-STATIONARY LLVL
THERMAL RIBBON THAT PRECIP WILL FOCUS ON AND OVER AND KEEP MOST OF
THE CWA DRY UNTIL TUE...JUST BATHED IN SEASONABLY COOL NORTHEAST
OR EASTERLY FLOW WITH JUST THE FAR SOUTHERN CWA GETTING CLIPPED BY
OVERRUNNING SHOWERS. THIS WHILE THE GFS AND GEM ARE FURTHER NORTH
WITH THE LLVL CONVERGENT AXIS AN BREAK OUT PERIODIC EPISODES OF
ELEVATED SHOWERS OR EVEN POSSIBLE MCS TYPE PRECIP COMPLEXES THROUGH
THE HOLIDAY WEEKEND OVER THE REGION. CLIMATOLOGY SUGGESTS A
COMPROMISE BETWEEN THE TWO CAMPS OF MODELS THAT THE SOUTHERN THIRD TO
HALF OF THE DVN CWA WILL BE UNDER THE GUN FOR A SOGGY HOLIDAY
WEEKEND. BELOW NORMAL TEMPS NORTH OF ANY BOUNDARY THAT SETS UP
ALONG OR JUST SOUTH OF THE CWA...POSSIBLY IN THE LOW 60S OR EVEN 50S
IF OVERRUNNING RAINS WIN OUT WHILE LAKE ENHANCED NORTHEAST SFC FLOW
SPILLS ACRS THE AREA ESPECIALLY ON SUNDAY. DIFFERENCES CONTINUE INTO
TUE AS THE GFS TRENDS DRIER SHIFTING THE MCS TRACK TO THE NORTH ACRS
MN AND WI FOR THE MID WEEK PERIOD...WHILE THE ECMWF ALSO TRENDS
NORTH BUT THAT TARGETS IA AND NORTHERN IL FOR A FAVORED MCS TRACK
FOR THE MID WEEK PERIOD. ..12..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1217 AM CDT WED MAY 22 2013
WEAKENING LOW PRESSURE SYSTEM OVER NORTHERN IOWA TO SLOWLY SHIFT
EAST OVERNIGHT INTO WISCONSIN WEDNESDAY. CURRENT VFR CONDITIONS
TO REMAIN OVERNIGHT AND THROUGH APPROXIMATELY 15Z WEDNESDAY
MORNING. MVFR CLOUDS TO MOVE INTO KCID AND KDBQ SHORTLY AFTER THE
LOW PASSES THESE LOCATIONS. CLOUDS TO RAISE TO VFR BEFORE MOVING
INTO KMLI AND KBRL. BY LATE MORNING SHOWERS TO DEVELOP NEAR
TERMINALS IN DIURNALLY DRIVEN CONVECTION. KMLI AND KBRL TO LOWER
INTO MVFR CIGS BY 03Z...WITH SHOWERS LINGERING IN THE AREA. VISBYS
TO REMAIN VFR THROUGHOUT. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DLF
SHORT TERM...DLF
LONG TERM...12
AVIATION...LE
000
FXUS63 KDVN 212338
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
638 PM CDT TUE MAY 21 2013
.SYNOPSIS...
ISSUED AT 240 PM CDT TUE MAY 21 2013
A CLOSED H5 LOW WAS LOCATED OVER SOUTHEASTERN SOUTH DAKOTA AND
SOUTHWESTERN MINNESOTA EARLY THIS AFTERNOON. AT THE SURFACE
ELONGATED LOW PRESSURE EXTENDED FROM SOUTHEAST SOUTH DAKOTA INTO
WISCONSIN WITH TWO CIRCULATION CENTERS LOCATED ON THE WESTERN AND
EASTERN PORTIONS OF THE TROF. A WEAK COLD FRONT OVER EASTERN
IOWA/NORTHWEST ILLINOIS THIS AFTERNOON ORIGINATED IN THE WISCONSIN
LOW WHILE A SECONDARY FRONT WAS JUST ENTERING NORTHWEST IOWA.
ANOTHER...STRONGER...CLOSED H5 LOW WAS JUST MOVING INTO THE
PACIFIC NORTHWEST AND SHOULD ACT AS A KICKER TO DISLODGE THE MID
WEST SYSTEM.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
THE SYSTEM OVER THE CENTRAL U.S. WILL STAY OVER MINNESOTA AND
SOUTH DAKOTA TONIGHT AND THEN DROP SOUTHEAST WEDNESDAY KEEPING THE
REGION IN COOL CYCLONIC FLOW THROUGH THE PERIOD.
WEAK CONVERGENCE ALONG THE MID MISSISSIPPI VALLEY COLD FRONT AND
MODEST CAPES AROUND 1000 J/KG WILL PROVIDE A CHANCE OF SOME
EVENING THUNDERSTORMS EAST OF THE MISSISSIPPI RIVER THIS EVENING. A
S/W OVER THE SOUTHERN PLAINS THIS AFTERNOON WILL LIFT NORTHEAST
TONIGHT SPREADING MORE SHOWERS INTO AREAS ALONG AND EAST OF THE
MISSISSIPPI RIVER LATE TONIGHT AND WEDNESDAY MORNING. WEDNESDAY
AFTERNOON...AS A WEAKENING SURFACE LOW MOVES SOUTHEAST THROUGH THE
REGION...WRAP AROUND SHOWERS WILL SPREAD OVER THE AREA WITH THE
BETTER CHANCES ALONG AND NORTH OF INTERSTATE 80. COOL AIR
ADVECTING IN TO THE REGION TONIGHT AND WEDNESDAY WILL BRING
TEMPERATURES IN THE 50S AND LOW 60S TONIGHT. WEDNESDAY WITH COOLER
AIR AND PLACE AND WIDESPREAD CLOUDS HIGHS WILL ONLY BE IN THE 60S
AND LOW 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
WEDNESDAY NIGHT AND THURSDAY...SHOWERS WILL LOOK TO PIVOT AROUND
WESTERN FLANK OF WESTERN GRT LKS TROF WED NIGHT AN MAY BE MORE
PREVALENT ALONG AND NORTH OF I80 FROM 00Z-06Z...AND THEN CONTINUE
TO ROTATE SOUTH AND EAST INTO THU MORNING. FCST SOUNDINGS SUGGEST
DEEPER SATURATED SOUNDINGS WED EVENING WITH PW/S PUSHING OVER AN
INCH...BUT FORCING AND INSTABILITY MARGINAL TO MAKE THE MOST OF THOSE
PROFILES. MOST AREAS TO GET 2 TENTHS OF AN INCH OR LESS BY THU
MORNING. WILL NOT MENTION ANY THUNDER THU EVENING WITH LIMITED
INSTABILITY PROFILES. TOP-DOWN SATURATION LATE WED NIGHT INTO THU
MORNING MAY TREND SHOWERS INTO MORE OF A DRIZZLE REGIME AFTER 3 AM
CDT. A COOL DAMP NIGHT WITH LOWS IN THE LOWER 50S WITH SOME UPPER
40S POSSIBLE. SECONDARY SATELLITE VORT SPOKE MAY KEEP SHOWERS
FESTERING ACRS THE SOUTHEASTERN HALF OF THE FCST AREA THU MORNING
BEFORE THAT ACTIVITY MOVES OUT OR DECAYS BY AFTERNOON. HIGHS HELD IN
THE 60S LATEST 12Z RUN MODELS IN GOOD AGREEMENT IN ADVERTISING
SEASONABLY STRONG BACKDOOR CANADIAN SFC HIGH DUMPING DOWN THE WESTERN
GRT LKS LATE THU AND THU NIGHT...WITH ASSOCIATED COOL PUSH AND CLOUD
CLEAR OFF SETTING THE STAGE FOR A CHILLY NIGHT THU NIGHT. CURRENTLY
PROGGED AIR MASS ADVECTING IN COULD SUPPORT WIDESPREAD LOWS BY FRI
MORNING IN THE LOWER 40S TO UPPER 30S...EXCEPT FOR MID 40S IN THE
SOUTHWESTERN CWA.
FRIDAY AND SATURDAY...AFTER COOL START TO THE DAY...FRI LOOKS TO BE
MAINLY SUNNY UNTIL SOME HIGH CLOUDS SPILL IN FROM THE WEST OFF
GATHERING CONVECTION IN RETURN FLOW ACRS THE PLAINS. WARM AIR
RETURN FLOW ALOFT ESPECIALLY AROUND THE H85 MB LAYER COULD LIMIT
MIXING DEPTH AND KEEP FRI HIGHS HELD IN THE MID 60S EVEN WITH A LOT
OF INSOLATION. FRI NIGHT SOLUTIONS START TO DIVERGE BETWEEN THE 12Z
GFS...THE ECMWF...UKMET AND GEM. THE ECMWF CONTINUES TO BE LESS
AMPLIFIED WITH MID CONUS UPPER RIDGING...ALLOWING MCS DEVELOPMENT
ACRS THE CENTRAL PLAINS TO LEE OF WESTERN CONUS TROFFINESS TO RIDGE-
RIDE AND PROPAGATE EASTWARD ALONG H85 MB BOUNDARY ACRS PORTIONS OR
ALL OF THE DVN CWA LATER FRI NIGHT AND INTO SAT MORNING. THE NEW 12Z
ECMWF FAVORS HEAVIER ELEVATED CONVECTION FED ON H85 THTA-E PLUME ACRS
THE SOUTHERN HALF TO THIRD OF THE DVN CWA FRI NIGHT..WHERE AREAS
COULD GET UP TO AN INCH OF RAINFALL BY SAT MORNING. THIS IN CONTRAST
TO THE MORE AMPLIFIED RIDGE AND FURTHER WE AXIS PLACEMENT OF THE
12Z GFS...WHICH KEEPS FRI NIGHT AND SAT MORNING BASICALLY DRY UNTIL
ELEVATED PRECIP SYSTEM MOVES IN FROM THE WEST BY LATE SAT AFTERNOON.
THE GFS THEN SUGGESTS LLJ AND WARM MOIST CONVEYOR INCREASING OFF THE
WESTERN GULF WILL FUEL A NOCTURNAL MCS TYPE FEATURE SAT NIGHT INTO
SUNDAY MORNING ACRS MOST OF THE LOCAL FCST AREA. THIS WHILE THE
CONSISTENT ECMWF IS FURTHER SOUTH WITH LLVL BAROCLINIC RIBBON LAY
OUT AS WELL AS SOUTHWESTERN GRT LKS LLVL RIDGE AND NORTHEAST BOUNDARY
LAYER PUSH KEEPING THE DVN CWA MAINLY DRY EXCEPT FOR SOME
OVERRUNNING SHOWERS ACRS THE FAR SOUTH SAT NIGHT. THE CANADIAN MORE
SIMILAR TO THE GFS FOR SAT NIGHT AND ADVERTISES UP TO 1.5 INCHES OF
RAIN ACRS THE HEART OF THE CWA BY 12Z SUNDAY. WITH UNCERTAINTIES...
WILL HAVE TO KEEP CHC POPS FOR ALMOST EVERY PERIOD WHICH WILL BE AN
UNFORTUNATE THEME THAT WILL LOOK TO REOCCUR THROUGH THE REST OF THE
LONG RANGE. BOUNDARY PLACEMENT...PRECIP EPISODES AND OUTFLOW/CLOUD
DEBRIS TO PLAY HAVOC WITH TEMP FCST/S THROUGH THE HOLIDAY WEEKEND.
SUNDAY THROUGH NEXT TUESDAY...AS STATED ABOVE...LARGE DIFFERENCES IN
MID CONUS RIDGE PLACEMENT OF THE MAIN AXIS AND AMPLIFICATION...AS
WELL AS NORTH-SOUTH LAY OUT DIFFERENCES OF WEST-TO-EAST ORIENTED LLVL
BOUNDARY OR H85 FRONT BETWEEN THE MEDIUM RANGE MODELS WILL AVERAGE
OUT TO DAILY CHC POPS THOUGH MOST OF THIS PERIOD. THE NEW EURO
CONTINUES TO BE FURTHER SOUTH WITH THE QUASI-STATIONARY LLVL
THERMAL RIBBON THAT PRECIP WILL FOCUS ON AND OVER AND KEEP MOST OF
THE CWA DRY UNTIL TUE...JUST BATHED IN SEASONABLY COOL NORTHEAST
OR EASTERLY FLOW WITH JUST THE FAR SOUTHERN CWA GETTING CLIPPED BY
OVERRUNNING SHOWERS. THIS WHILE THE GFS AND GEM ARE FURTHER NORTH
WITH THE LLVL CONVERGENT AXIS AN BREAK OUT PERIODIC EPISODES OF
ELEVATED SHOWERS OR EVEN POSSIBLE MCS TYPE PRECIP COMPLEXES THROUGH
THE HOLIDAY WEEKEND OVER THE REGION. CLIMATOLOGY SUGGESTS A
COMPROMISE BETWEEN THE TWO CAMPS OF MODELS THAT THE SOUTHERN THIRD TO
HALF OF THE DVN CWA WILL BE UNDER THE GUN FOR A SOGGY HOLIDAY
WEEKEND. BELOW NORMAL TEMPS NORTH OF ANY BOUNDARY THAT SETS UP
ALONG OR JUST SOUTH OF THE CWA...POSSIBLY IN THE LOW 60S OR EVEN 50S
IF OVERRUNNING RAINS WIN OUT WHILE LAKE ENHANCED NORTHEAST SFC FLOW
SPILLS ACRS THE AREA ESPECIALLY ON SUNDAY. DIFFERENCES CONTINUE INTO
TUE AS THE GFS TRENDS DRIER SHIFTING THE MCS TRACK TO THE NORTH ACRS
MN AND WI FOR THE MID WEEK PERIOD...WHILE THE ECMWF ALSO TRENDS
NORTH BUT THAT TARGETS IA AND NORTHERN IL FOR A FAVORED MCS TRACK
FOR THE MID WEEK PERIOD. ..12..
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 632 PM CDT TUE MAY 21 2013
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. SOUTHWEST WINDS TO
GRADUALLY BECOME WEST WEDNESDAY MORNING. TONIGHT ISOLATED
THUNDERSTORMS ARE POSSIBLE...BUT DUE TO COVERAGE CONCERNS HAVE
LEFT OUT OF FORECAST FOR NOW. LATER THIS EVENING A BAND OF RAIN
WITH EMBEDDED THUNDER IS EXPECTED TO MOVE UP TO AFFECT THE
SOUTHEAST PORTIONS OF THE FORECAST AREA...BUT FOR NOW IT APPEARS
WILL MISS BOTH KBRL AND KMLI...AND HAVE LEFT OUT OF THOSE
FORECASTS AS WELL...AND WILL HAVE TO WAIT AND SEE HOW THIS
DEVELOPS BEFORE PUTTING INTO FORECAST. WEDNESDAY MORNING AN AREA
OF MVFR CIGS TO SPREAD INTO KCID AND KDBQ FROM THE WEST...AND
SHOULD REMAIN MVFR MOST OF THE DAY. THESE ARE NOT GOING TO GET FAR
ENOUGH EAST TO GET TO KMLI OR KBRL BEFORE LIFTING TO A VFR LAYER
OF CLOUDS. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DLF
SHORT TERM...DLF
LONG TERM...12
AVIATION...LE
000
FXUS63 KDVN 212031
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
331 PM CDT TUE MAY 21 2013
.SYNOPSIS...
ISSUED AT 240 PM CDT TUE MAY 21 2013
A CLOSED H5 LOW WAS LOCATED OVER SOUTHEASTERN SOUTH DAKOTA AND
SOUTHWESTERN MINNESOTA EARLY THIS AFTERNOON. AT THE SURFACE
ELONGATED LOW PRESSURE EXTENDED FROM SOUTHEAST SOUTH DAKOTA INTO
WISCONSIN WITH TWO CIRCULATION CENTERS LOCATED ON THE WESTERN AND
EASTERN PORTIONS OF THE TROF. A WEAK COLD FRONT OVER EASTERN
IOWA/NORTHWEST ILLINOIS THIS AFTERNOON ORIGINATED IN THE WISCONSIN
LOW WHILE A SECONDARY FRONT WAS JUST ENTERING NORTHWEST IOWA.
ANOTHER...STRONGER...CLOSED H5 LOW WAS JUST MOVING INTO THE
PACIFIC NORTHWEST AND SHOULD ACT AS A KICKER TO DISLODGE THE MID
WEST SYSTEM.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
THE SYSTEM OVER THE CENTRAL U.S. WILL STAY OVER MINNESOTA AND
SOUTH DAKOTA TONIGHT AND THEN DROP SOUTHEAST WEDNESDAY KEEPING THE
REGION IN COOL CYCLONIC FLOW THROUGH THE PERIOD.
WEAK CONVERGENCE ALONG THE MID MISSISSIPPI VALLEY COLD FRONT AND
MODEST CAPES AROUND 1000 J/KG WILL PROVIDE A CHANCE OF SOME
EVENING THUNDERSTORMS EAST OF THE MISSISSIPPI RIVER THIS EVENING. A
S/W OVER THE SOUTHERN PLAINS THIS AFTERNOON WILL LIFT NORTHEAST
TONIGHT SPREADING MORE SHOWERS INTO AREAS ALONG AND EAST OF THE
MISSISSIPPI RIVER LATE TONIGHT AND WEDNESDAY MORNING. WEDNESDAY
AFTERNOON...AS A WEAKENING SURFACE LOW MOVES SOUTHEAST THROUGH THE
REGION...WRAP AROUND SHOWERS WILL SPREAD OVER THE AREA WITH THE
BETTER CHANCES ALONG AND NORTH OF INTERSTATE 80. COOL AIR
ADVECTING IN TO THE REGION TONIGHT AND WEDNESDAY WILL BRING
TEMPERATURES IN THE 50S AND LOW 60S TONIGHT. WEDNESDAY WITH COOLER
AIR AND PLACE AND WIDESPREAD CLOUDS HIGHS WILL ONLY BE IN THE 60S
AND LOW 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 240 PM CDT TUE MAY 21 2013
WEDNESDAY NIGHT AND THURSDAY...SHOWERS WILL LOOK TO PIVOT AROUND
WESTERN FLANK OF WESTERN GRT LKS TROF WED NIGHT AN MAY BE MORE
PREVALENT ALONG AND NORTH OF I80 FROM 00Z-06Z...AND THEN CONTINUE
TO ROTATE SOUTH AND EAST INTO THU MORNING. FCST SOUNDINGS SUGGEST
DEEPER SATURATED SOUNDINGS WED EVENING WITH PW/S PUSHING OVER AN
INCH...BUT FORCING AND INSTABILITY MARGINAL TO MAKE THE MOST OF THOSE
PROFILES. MOST AREAS TO GET 2 TENTHS OF AN INCH OR LESS BY THU
MORNING. WILL NOT MENTION ANY THUNDER THU EVENING WITH LIMITED
INSTABILITY PROFILES. TOP-DOWN SATURATION LATE WED NIGHT INTO THU
MORNING MAY TREND SHOWERS INTO MORE OF A DRIZZLE REGIME AFTER 3 AM
CDT. A COOL DAMP NIGHT WITH LOWS IN THE LOWER 50S WITH SOME UPPER
40S POSSIBLE. SECONDARY SATELLITE VORT SPOKE MAY KEEP SHOWERS
FESTERING ACRS THE SOUTHEASTERN HALF OF THE FCST AREA THU MORNING
BEFORE THAT ACTIVITY MOVES OUT OR DECAYS BY AFTERNOON. HIGHS HELD IN
THE 60S LATEST 12Z RUN MODELS IN GOOD AGREEMENT IN ADVERTISING
SEASONABLY STRONG BACKDOOR CANADIAN SFC HIGH DUMPING DOWN THE WESTERN
GRT LKS LATE THU AND THU NIGHT...WITH ASSOCIATED COOL PUSH AND CLOUD
CLEAR OFF SETTING THE STAGE FOR A CHILLY NIGHT THU NIGHT. CURRENTLY
PROGGED AIR MASS ADVECTING IN COULD SUPPORT WIDESPREAD LOWS BY FRI
MORNING IN THE LOWER 40S TO UPPER 30S...EXCEPT FOR MID 40S IN THE
SOUTHWESTERN CWA.
FRIDAY AND SATURDAY...AFTER COOL START TO THE DAY...FRI LOOKS TO BE
MAINLY SUNNY UNTIL SOME HIGH CLOUDS SPILL IN FROM THE WEST OFF
GATHERING CONVECTION IN RETURN FLOW ACRS THE PLAINS. WARM AIR
RETURN FLOW ALOFT ESPECIALLY AROUND THE H85 MB LAYER COULD LIMIT
MIXING DEPTH AND KEEP FRI HIGHS HELD IN THE MID 60S EVEN WITH A LOT
OF INSOLATION. FRI NIGHT SOLUTIONS START TO DIVERGE BETWEEN THE 12Z
GFS...THE ECMWF...UKMET AND GEM. THE ECMWF CONTINUES TO BE LESS
AMPLIFIED WITH MID CONUS UPPER RIDGING...ALLOWING MCS DEVELOPMENT
ACRS THE CENTRAL PLAINS TO LEE OF WESTERN CONUS TROFFINESS TO RIDGE-
RIDE AND PROPAGATE EASTWARD ALONG H85 MB BOUNDARY ACRS PORTIONS OR
ALL OF THE DVN CWA LATER FRI NIGHT AND INTO SAT MORNING. THE NEW 12Z
ECMWF FAVORS HEAVIER ELEVATED CONVECTION FED ON H85 THTA-E PLUME ACRS
THE SOUTHERN HALF TO THIRD OF THE DVN CWA FRI NIGHT..WHERE AREAS
COULD GET UP TO AN INCH OF RAINFALL BY SAT MORNING. THIS IN CONTRAST
TO THE MORE AMPLIFIED RIDGE AND FURTHER WE AXIS PLACEMENT OF THE
12Z GFS...WHICH KEEPS FRI NIGHT AND SAT MORNING BASICALLY DRY UNTIL
ELEVATED PRECIP SYSTEM MOVES IN FROM THE WEST BY LATE SAT AFTERNOON.
THE GFS THEN SUGGESTS LLJ AND WARM MOIST CONVEYOR INCREASING OFF THE
WESTERN GULF WILL FUEL A NOCTURNAL MCS TYPE FEATURE SAT NIGHT INTO
SUNDAY MORNING ACRS MOST OF THE LOCAL FCST AREA. THIS WHILE THE
CONSISTENT ECMWF IS FURTHER SOUTH WITH LLVL BAROCLINIC RIBBON LAY
OUT AS WELL AS SOUTHWESTERN GRT LKS LLVL RIDGE AND NORTHEAST BOUNDARY
LAYER PUSH KEEPING THE DVN CWA MAINLY DRY EXCEPT FOR SOME
OVERRUNNING SHOWERS ACRS THE FAR SOUTH SAT NIGHT. THE CANADIAN MORE
SIMILAR TO THE GFS FOR SAT NIGHT AND ADVERTISES UP TO 1.5 INCHES OF
RAIN ACRS THE HEART OF THE CWA BY 12Z SUNDAY. WITH UNCERTAINTIES...
WILL HAVE TO KEEP CHC POPS FOR ALMOST EVERY PERIOD WHICH WILL BE AN
UNFORTUNATE THEME THAT WILL LOOK TO REOCCUR THROUGH THE REST OF THE
LONG RANGE. BOUNDARY PLACEMENT...PRECIP EPISODES AND OUTFLOW/CLOUD
DEBRIS TO PLAY HAVOC WITH TEMP FCST/S THROUGH THE HOLIDAY WEEKEND.
SUNDAY THROUGH NEXT TUESDAY...AS STATED ABOVE...LARGE DIFFERENCES IN
MID CONUS RIDGE PLACEMENT OF THE MAIN AXIS AND AMPLIFICATION...AS
WELL AS NORTH-SOUTH LAY OUT DIFFERENCES OF WEST-TO-EAST ORIENTED LLVL
BOUNDARY OR H85 FRONT BETWEEN THE MEDIUM RANGE MODELS WILL AVERAGE
OUT TO DAILY CHC POPS THOUGH MOST OF THIS PERIOD. THE NEW EURO
CONTINUES TO BE FURTHER SOUTH WITH THE QUASI-STATIONARY LLVL
THERMAL RIBBON THAT PRECIP WILL FOCUS ON AND OVER AND KEEP MOST OF
THE CWA DRY UNTIL TUE...JUST BATHED IN SEASONABLY COOL NORTHEAST
OR EASTERLY FLOW WITH JUST THE FAR SOUTHERN CWA GETTING CLIPPED BY
OVERRUNNING SHOWERS. THIS WHILE THE GFS AND GEM ARE FURTHER NORTH
WITH THE LLVL CONVERGENT AXIS AN BREAK OUT PERIODIC EPISODES OF
ELEVATED SHOWERS OR EVEN POSSIBLE MCS TYPE PRECIP COMPLEXES THROUGH
THE HOLIDAY WEEKEND OVER THE REGION. CLIMATOLOGY SUGGESTS A
COMPROMISE BETWEEN THE TWO CAMPS OF MODELS THAT THE SOUTHERN THIRD TO
HALF OF THE DVN CWA WILL BE UNDER THE GUN FOR A SOGGY HOLIDAY
WEEKEND. BELOW NORMAL TEMPS NORTH OF ANY BOUNDARY THAT SETS UP
ALONG OR JUST SOUTH OF THE CWA...POSSIBLY IN THE LOW 60S OR EVEN 50S
IF OVERRUNNING RAINS WIN OUT WHILE LAKE ENHANCED NORTHEAST SFC FLOW
SPILLS ACRS THE AREA ESPECIALLY ON SUNDAY. DIFFERENCES CONTINUE INTO
TUE AS THE GFS TRENDS DRIER SHIFTING THE MCS TRACK TO THE NORTH ACRS
MN AND WI FOR THE MID WEEK PERIOD...WHILE THE ECMWF ALSO TRENDS
NORTH BUT THAT TARGETS IA AND NORTHERN IL FOR A FAVORED MCS TRACK
FOR THE MID WEEK PERIOD. ..12..
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1208 PM CDT TUE MAY 21 2013
STALLED LOW PRESSURE OVER MN WILL WILL DROP SOUTHEAST THROUGH
EASTERN IA AND WEAKEN LATE TONIGHT AND WEDNESDAY MORNING.
WIDESPREAD CU BASED AROUND 35HND FEET THIS AFTERNOON WILL
DISSIPATE WITH LOSS OF HEATING BY EARLY THIS EVENING. AN AREA OF
SHOWERS WILL LIFT NORTHEAST BRUSHING LOCATIONS NEAR AND EAST OF
THE MISSISSIPPI RIVER LATE TONIGHT AND WEDNESDAY. AT THIS TIME IT
APPEARS FLIGHT CONDITIONS WILL REMAIN VFR IN THE SHOWERS EXCEPT AT
KDBQ WHERE CIGS COULD DROP BELOW 3KFT. FURTHER WEST...AN AREA OF
MVFR CLOUDS AND SCATTERED SHRA WILL ACCOMPANY THE WEAKENING LOW
PRESSURE AS IT MOVES THROUGH THE REGION. MVFR CIGS SHOULD REACH KCID
AFTER 12Z WEDNESDAY.
DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...DLF
SHORT TERM...DLF
LONG TERM...12
AVIATION...DLF
| 
