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
000
FXUS63 KDVN 211717
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1217 PM CDT TUE MAY 21 2013
.SYNOPSIS...
ISSUED AT 255 AM CDT TUE MAY 21 2013
ANALYSIS SHOWS LARGE SURFACE AND UPPER LOW SYSTEM PIN WHEELING ACROSS
THE EASTERN DAKOTAS MOVING SLOWLY SOUTHEAST. THIS PUTS FORECAST AREA
IN DRY SLOT WHICH WILL CONTINUE FOR ROUGHLY THE NEXT 12-15 HOURS.
DIFFUSE COOL FRONT WILL MOVE ACROSS THE AREA THIS EVENING BRINGING
CLOUDS AND COOLER TEMPERATURES. VERIFICATION AT 2 AM SHOWS COOL
AIR ON BACK SIDE OF SYSTEM ON THE STRONGER SIDE OF ALL SOLUTIONS.
UPSTREAM ENERGY SUPPORTS BELOW NORMAL TEMPERATURES AND ACTIVE
WESTERLY FLOW THE NEXT 5 PLUS DAYS AND POSSIBLY LONGER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 255 AM CDT TUE MAY 21 2013
TODAY...SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH BY MID DAY
WITH PARTLY TO MOSTLY SUNNY SKIES. THIS WILL RESULT IN A DAY SIMILAR
TO YESTERDAY WITH LOWERING DEWPOINTS AND HIGHS A DEGREE OR TWO
LOWER TODAY FOR A NICE AND COMFORTABLE LATE SPRING DAY. HAVE KEPT
ISOLATED SHOWER OR THUNDERSTORM LOCATIONS MAINLY EAST OF THE
MISSISSIPPI RIVER MID TO LATE PM BUT LATER SHIFTS MAY BE ABLE TO
REMOVE DUE TO MIXING OF LOWER DEWPOINTS AND LACK OF A FORCING
FOCUS. HIGHS SHOULD RANGE FROM AROUND 73-74 FAR NW TO 80-82 SE
SECTIONS.
TONIGHT...CLOUDS TO INCREASE WITH WAVE FROM SOUTHERN PLAINS TO IMPACT
LOCATIONS ALONG AND EAST OF THE MISSISSIPPI TOWARD DAYBREAK. UPPED
POPS TO LIKELY FAR EAST WITH SHOWERS AND MORE PROBABLY JUST LIGHT RAIN.
THE MOSTLY SLIGHT CHANCE EVENING POPS OF THUNDER MAY BE ABLE TO CHANGED
TO JUST SHOWERS WITH LACK OF FOCUS AND INSTABILITY BY LATER SHIFTS.
NICHOLS
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 255 AM CDT TUE MAY 21 2013
THE MODELS SHOW A RESPECTABLE SURFACE WAVE MOVING THROUGH THE AREA
ON WEDNESDAY BRINGING A THREAT OF RAIN TO THE AREA. THE POSSIBILITY
OF THUNDERSTORMS IS QUESTIONABLE GIVEN HOW COOL THE AIRMASS IS AND
WHAT IS SUGGESTED IN THE FCST SOUNDINGS. HOWEVER...HAVE ELECTED TO
KEEP A MENTION OF ISOLATED THUNDERSTORMS OVER ROUGHLY THE EASTERN
HALF OF THE CWFA WED AFTERNOON WHERE SLIGHTLY STRONGER LIFT IS
INDICATED BY THE MODELS.
WED NIGHT/THURSDAY MORNING SHOWERS WILL PERSIST ACROSS THE AREA AS
THE SFC LOW SLOWLY MOVES EAST INTO INDIANA. BY THURSDAY AFTERNOON
MOST OF THE AREA SHOULD BE DRY AS THE BETTER MOISTURE AND FORCING
MOVES EAST OF THE AREA. TEMPERATURES ON THURSDAY WILL BE BELOW
NORMAL.
THURSDAY NIGHT WILL BE CHILLY AND DRY AS A VERY COOL CANADIAN
AIRMASS BUILDS INTO THE AREA.
FRIDAY ON...
THE MODEL CONSENSUS HAS COOL AND DRY CONDITIONS ACROSS THE AREA ON
FRIDAY WITH CANADIAN HIGH PRESSURE OVER THE GREAT LAKES.
THE MODEL CONSENSUS HAS SCHC/CHC POPS FRIDAY NIGHT AND THEN CHC POPS
FROM SATURDAY THROUGH MONDAY. THE MODELS GENERALLY AGREE ON
DEVELOPING RETURN FLOW FRIDAY NIGHT BUT THE STRENGTH OF THE CANADIAN
HIGH COMBINED WITH FLOW OFF LAKE MICHIGAN WILL HELP KEEP AN
EFFECTIVE BOUNDARY ACROSS THE AREA. DISTURBANCES ARRIVING FROM THE
PLAINS WILL INTERACT WITH THIS BOUNDARY AND BRING A NEAR DAILY
THREAT OF RAIN TO THE AREA FROM SATURDAY THROUGH MONDAY.
THE FLOW OFF LAKE MICHIGAN WILL ALSO RESULT IN TEMPERATURES WELL
BELOW NORMAL FROM FRIDAY THROUGH SUNDAY.
08
&&
.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...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...DLF
000
FXUS63 KDVN 211142
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
642 AM CDT TUE MAY 21 2013
.SYNOPSIS...
ISSUED AT 255 AM CDT TUE MAY 21 2013
ANALYSIS SHOWS LARGE SURFACE AND UPPER LOW SYSTEM PIN WHEELING ACROSS
THE EASTERN DAKOTAS MOVING SLOWLY SOUTHEAST. THIS PUTS FORECAST AREA
IN DRY SLOT WHICH WILL CONTINUE FOR ROUGHLY THE NEXT 12-15 HOURS.
DIFFUSE COOL FRONT WILL MOVE ACROSS THE AREA THIS EVENING BRINGING
CLOUDS AND COOLER TEMPERATURES. VERIFICATION AT 2 AM SHOWS COOL
AIR ON BACK SIDE OF SYSTEM ON THE STRONGER SIDE OF ALL SOLUTIONS.
UPSTREAM ENERGY SUPPORTS BELOW NORMAL TEMPERATURES AND ACTIVE
WESTERLY FLOW THE NEXT 5 PLUS DAYS AND POSSIBLY LONGER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 255 AM CDT TUE MAY 21 2013
TODAY...SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 MPH BY MID DAY
WITH PARTLY TO MOSTLY SUNNY SKIES. THIS WILL RESULT IN A DAY SIMILAR
TO YESTERDAY WITH LOWERING DEWPOINTS AND HIGHS A DEGREE OR TWO
LOWER TODAY FOR A NICE AND COMFORTABLE LATE SPRING DAY. HAVE KEPT
ISOLATED SHOWER OR THUNDERSTORM LOCATIONS MAINLY EAST OF THE
MISSISSIPPI RIVER MID TO LATE PM BUT LATER SHIFTS MAY BE ABLE TO
REMOVE DUE TO MIXING OF LOWER DEWPOINTS AND LACK OF A FORCING
FOCUS. HIGHS SHOULD RANGE FROM AROUND 73-74 FAR NW TO 80-82 SE
SECTIONS.
TONIGHT...CLOUDS TO INCREASE WITH WAVE FROM SOUTHERN PLAINS TO IMPACT
LOCATIONS ALONG AND EAST OF THE MISSISSIPPI TOWARD DAYBREAK. UPPED
POPS TO LIKELY FAR EAST WITH SHOWERS AND MORE PROBABLY JUST LIGHT RAIN.
THE MOSTLY SLIGHT CHANCE EVENING POPS OF THUNDER MAY BE ABLE TO CHANGED
TO JUST SHOWERS WITH LACK OF FOCUS AND INSTABILITY BY LATER SHIFTS.
NICHOLS
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 255 AM CDT TUE MAY 21 2013
THE MODELS SHOW A RESPECTABLE SURFACE WAVE MOVING THROUGH THE AREA
ON WEDNESDAY BRINGING A THREAT OF RAIN TO THE AREA. THE POSSIBILITY
OF THUNDERSTORMS IS QUESTIONABLE GIVEN HOW COOL THE AIRMASS IS AND
WHAT IS SUGGESTED IN THE FCST SOUNDINGS. HOWEVER...HAVE ELECTED TO
KEEP A MENTION OF ISOLATED THUNDERSTORMS OVER ROUGHLY THE EASTERN
HALF OF THE CWFA WED AFTERNOON WHERE SLIGHTLY STRONGER LIFT IS
INDICATED BY THE MODELS.
WED NIGHT/THURSDAY MORNING SHOWERS WILL PERSIST ACROSS THE AREA AS
THE SFC LOW SLOWLY MOVES EAST INTO INDIANA. BY THURSDAY AFTERNOON
MOST OF THE AREA SHOULD BE DRY AS THE BETTER MOISTURE AND FORCING
MOVES EAST OF THE AREA. TEMPERATURES ON THURSDAY WILL BE BELOW
NORMAL.
THURSDAY NIGHT WILL BE CHILLY AND DRY AS A VERY COOL CANADIAN
AIRMASS BUILDS INTO THE AREA.
FRIDAY ON...
THE MODEL CONSENSUS HAS COOL AND DRY CONDITIONS ACROSS THE AREA ON
FRIDAY WITH CANADIAN HIGH PRESSURE OVER THE GREAT LAKES.
THE MODEL CONSENSUS HAS SCHC/CHC POPS FRIDAY NIGHT AND THEN CHC POPS
FROM SATURDAY THROUGH MONDAY. THE MODELS GENERALLY AGREE ON
DEVELOPING RETURN FLOW FRIDAY NIGHT BUT THE STRENGTH OF THE CANADIAN
HIGH COMBINED WITH FLOW OFF LAKE MICHIGAN WILL HELP KEEP AN
EFFECTIVE BOUNDARY ACROSS THE AREA. DISTURBANCES ARRIVING FROM THE
PLAINS WILL INTERACT WITH THIS BOUNDARY AND BRING A NEAR DAILY
THREAT OF RAIN TO THE AREA FROM SATURDAY THROUGH MONDAY.
THE FLOW OFF LAKE MICHIGAN WILL ALSO RESULT IN TEMPERATURES WELL
BELOW NORMAL FROM FRIDAY THROUGH SUNDAY.
08
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 635 AM CDT TUE MAY 21 2013
SCT/BKN IFR CLOUD DECK TO DISSIPATE BY 15Z. THEN...VFR CONDITIONS
TO PREVAIL INTO WEDNESDAY MORNING. AREA TO EXPERIENCE SW WINDS OF
15 TO 25 MPH AND PARTLY SUNNY SKIES ALL TERMINALS WITH A DRY SLOT
AHEAD OF UPPER NORTHERN PLAINS LOW PRESSURE SYSTEM. DIFFUSE FRONT
TO PASS TONIGHT WITH A WAVE THAT MAY BRING A CHANCE OF LIGHT RAIN
AND CIGS TO BRL-MLI TERMINALS OF 3-5K AGL BY 22/12Z.
NICHOLS
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...NICHOLS
000
FXUS63 KDVN 210543
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1243 AM CDT TUE MAY 21 2013
.SYNOPSIS...
ISSUED AT 248 PM CDT MON MAY 20 2013
LATEST SFC ANALYSIS WAS INDICATING OCCLUDING CYCLONE COMPLEX ACRS
THE EASTERN SD/ND REGION...WITH LEAD FRONT PUSHING ACRS WESTERN IA
BUT BETTER COLD WRAP AROUND NOTED ACRS SD INTO CENTRAL NEB. THE
REGION HAS BEEN PRETTY MUCH BATHED IN PRESSURE RISES TODAY...BUT
FALLS INCREASING ACRS WESTERN AND NORTHWESTERN MO. MAIN WARM FRONT
ACRS CENTRAL MN...FAR NORTHERN WI INTO THE NORTHERN LOWER MI.
SECONDARY FRONT ACRS WESTERN OK...AND REMNANT OUTFLOW BOUNDARY
ACRS CENTRAL MO ACTING AS BETTER SFC DPT POOLING MECHANISMS.
LOCALLY IN SOUTHWEST SFC FLOW...SFC DPTS HAVING TROUBLE GETTING
OUT OF THE LOWER 60S WITH FETCH BACK INTO SIMILAR AIR MASS IN
NORTHEASTERN KS/FAR NW MO. CUT-OFF UPPER LOW ALMOST STACKED OVER
SFC FEATURE...WITH WATER VAPOR IMAGERY INDICATING NOSE OF MID/UPPER
LEVEL SPEED MAX PUSHING ACRS NORTHEASTERN KS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY MORNING)
ISSUED AT 248 PM CDT MON MAY 20 2013
TONIGHT...ASSESSING LOCAL INSTABILITY PARAMETERS...CAPES HAVE GROWN
TO ONLY 500 TO MAYBE 1000 J/KG ACRS PORTIONS OF THE DVN CWA...WITH
18Z SOUNDING SHOWING ROBUST H85 CAP/CONVECTIVE TEMP IN THE UPPER
80S. LACK OF AMBIENT CU LOCALLY A CLUE. DEEP UNIFORM SOUTHWESTERLIES
MAKING FOR MODERATE SHEAR/SPEED/ AT BEST. WITH MAIN VORT AND
MID/UPPER LEVEL VORT MAX STILL ACRS KS...DEEPER FORCING TO NOT
ARRIVE UNTIL MAINLY AFTER 00Z. THUS REST OF THIS AFTERNOON MAY SEE
A LACK OF CONVECTIVE ACTIVITY. WITH DEEP CONVECTIVE INDICE MAX
REALIGNING ACRS EASTERN KS INTO WESTERN/NORTHWEST MO THE REST OF THIS
AFTERNOON AND EARLY EVENING...EXPECT STORM DEVELOPMENT IN THESE
AREAS TO MOVE NORTHEAST AND BE THE SCTRD STORMS TO AFFECT PORTIONS
OF THE CWA THIS EVENING. THIS AND POSSIBLY SOME DEVELOPMENT AHEAD
OF THE WESTERN IA FRONT IN CU FIELD ONGOING OUT THERE ATTM. BUT
WITH YET UNFAVORABLE AIRMASS IN PLACE TO SUPPORT STRONG
CONVECTION...THIS ACTIVITY MAY WEAKEN AS IT ARRIVES UNLESS SOME
THERMODYNAMIC SUPPORT IS ADVECTED INTO THE AREA FROM THE
SOUTHWEST. MUCH UNCERTAINTY REGARDING THIS ATTM. IF STORMS DO
MAINTAIN AND MAKE IT INTO THE AREA...STILL A CHANCE FOR SOME SVR
CELLS LOOKING AT CURRENT AND PROGGED SHEAR PROFILES BUT MAIN
THREATS WOULD BE LARGE HAIL AND DAMAGING WIND GUSTS WITH ANY LINER/BOWING
DEVELOPMENT IN UNIFORM VERTICAL WIND FIELDS. LLVL SHEAR DIRECTION
AND HIGHER LCL/S OF AT LEAST 3K FT AGL CURRENTLY NOT THAT CONDUCIVE
FOR TORNADIC DEVELOPMENT. WILL KNOCK DOWN 00Z-06Z COVERAGE TO HIGH
CHC AND LIKELY POPS ACRS MOST OF THE DVN CWA...THEN WALK OUT ANY
LINGERING ACTIVITY AFTER 08Z FROM THE EASTERN CWA. LOCALLY HEAVY
RAINFALL BURSTS POSSIBLE...BUT MOVEMENT OF STORMS HOPEFULLY WILL
PRECLUDE MUCH OF ANY FLASH FLOOD THREAT UNLESS THE SAME AREA GETS
HIT REPEATEDLY AND HAD SIGNIFICANT RAIN LAST NIGHT. LOWS MAY DIP
INTO THE UPPER 50S IN THE NORTHWESTERN FCST AREA...BUT HELD IN THE
60S ELSEWHERE. ..12..
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY) ISSUED AT 248 PM CDT
MON MAY 20 2013
UPPER LOW OVER THE NORTHERN PLAINS TO GRADUALLY FILL AND SHIFT
EASTWARD THROUGH MIDWEEK...REPLACED BY HIGH PRESSURE AT THE SURFACE
AND MID LEVEL RIDGING. THIS WILL PROVIDE A CHANGE TO BELOW NORMAL
TEMPERATURES AND DRY WEATHER BY LATE WEEK. OVER THE WEEKEND...A
COOLER...UNSETTLED PATTERN DEVELOPS AS RETURNING MOISTURE INTERACTS
WITH A BOUNDARY OVER THE AREA.
TUESDAY...SURFACE LOW GRADUALLY EJECTS EASTWARD INTO THE UPPER MS
VALLEY. THIS WILL SEND THE OCCLUDED FRONT EASTWARD THROUGH THE
FORECAST AREA IN THE MORNING...THEN A SECONDARY TROUGH IS INDICATED
BY THE NAM DURING PEAK HEATING. EACH OF THESE FEATURES WILL POSSIBLY
TRIGGER SHOWERS AND THUNDERSTORMS...BUT WITH LOW CONFIDENCE IN
THE TIMING...STRENGTH...OR AVAILABLE INSTABILITY WITH THESE
FEATURES...HAVE ONLY CHANCE POPS THROUGH THE DAY. SUPPORT FOR SEVERE
STORMS IS LACKING DUE TO LESS FAVORABLE SHEAR PROFILES AND LIKELY
LESS AVAILABLE INSTABILITY THAN THE PAST COUPLE DAYS. COOLER
TEMPERATURES AT 850 MB AND LIKELIHOOD OF MORE CLOUDS SHOULD LIMIT
HIGHS TO THE MID 70S WEST TO POSSIBLY MID 80S EAST.
TUESDAY NIGHT INTO WED...SURFACE LOW TRANSITIONING EASTWARD INTO THE
GREAT LAKES AND FILLING UPPER LOW MIGRATING OVERHEAD TO KEEP
CHANCES FOR MAINLY DIURNAL SHOWERS GOING WITH HIGHEST POPS IN THE
EAST. ADVECTION OF COOLER... DRIER AIR TO ALLOW MINS TO COOL INTO
THE 50S WITH WED HIGHS LIMITED TO THE UPPER 60S TO LOWER 70S.
THURSDAY AND FRIDAY...UPPER TROUGH ADVANCES EASTWARD ALLOWING
CANADIAN HIGH PRESSURE TO BUILD SOUTHEAST INTO THE GREAT LAKES.
HAVE TWEAKED TEMPERATURES DOWNWARD SOME TO LIMIT HIGHS TO THE 60S
AND POSSIBLY LOWER 70S FOR FRI...WHILE LOWS THURSDAY NIGHT SHOULD BE
WIDESPREAD IN THE 40S AS THE CENTER OF THE INCOMING RIDGE PASSES
OVERHEAD.
SATURDAY THROUGH MONDAY REMAINS A BELOW AVERAGE CONFIDENCE FORECAST
PERIOD AS THERE IS LITTLE AGREEMENT IN THE DETAILS OF RETURN
WARM...MOIST ADVECTION FLOW...THE ASSOCIATED BOUNDARY...AND WHERE
PRECIPITATION WILL SET UP. FOR NOW...A BLENDED APPROACH TO DIVERSE
SOLUTIONS WILL KEEP AN EXTENDED PERIOD OF CHANCE POPS WITH
TEMPERATURES GRADUALLY WARMING TO NEAR OR ABOVE NORMAL BY MONDAY
WHEN THE ODDS ARE GREATER THAT THE FRONT WILL HAVE LIFTED NORTH OF
THE AREA. SHEETS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1232 AM CDT TUE MAY 21 2013
FEW SHOWERS AND ISOLD STORM CURRENTLY OVER EASTERN IOWA AND WILL
REMAIN POSSIBLE REST OF OVERNIGHT UNTIL MID AM TUE...BUT
CONFIDENCE TOO LOW FOR INCLUSION AT TERMINALS ASIDE FROM KDBQ
WHERE VCSH NEXT COUPLE OF HOURS. SOME PATCHY FOG POSSIBLE
ESPECIALLY IN AREAS THAT RECEIVED RAINFALL PAST 12 HRS...WHICH
INCLUDES KBRL. HAVE OPTED FOR TEMPO OF MVFR VSBYS AT KBRL AROUND
SUNRISE. OTHERWISE... KEPT REST OF THE TAF CYCLE DRY ALTHOUGH
CANT RULE OUT SOME PCPN ESPECIALLY EAST OF THE TERMINALS BY MID TO
LATE AFTERNOON DEVELOPING AHEAD OF PLAINS UPPER LOW AS IT DRIFTS
SLOWLY INTO THE UPPER MIDWEST. WINDS TO BECOME GUSTY FROM
SOUTHWEST TODAY AT 15 TO 25 KTS...THEN DIMINISH BELOW 10 KTS
TOWARD SUNSET AND MAY BECOME LIGHT AND VARIABLE.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...SHEETS
AVIATION...05
000
FXUS63 KDVN 202350
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
650 PM CDT MON MAY 20 2013
.SYNOPSIS...
ISSUED AT 248 PM CDT MON MAY 20 2013
LATEST SFC ANALYSIS WAS INDICATING OCCLUDING CYCLONE COMPLEX ACRS
THE EASTERN SD/ND REGION...WITH LEAD FRONT PUSHING ACRS WESTERN IA
BUT BETTER COLD WRAP AROUND NOTED ACRS SD INTO CENTRAL NEB. THE
REGION HAS BEEN PRETTY MUCH BATHED IN PRESSURE RISES TODAY...BUT
FALLS INCREASING ACRS WESTERN AND NORTHWESTERN MO. MAIN WARM FRONT
ACRS CENTRAL MN...FAR NORTHERN WI INTO THE NORTHERN LOWER MI.
SECONDARY FRONT ACRS WESTERN OK...AND REMNANT OUTFLOW BOUNDARY
ACRS CENTRAL MO ACTING AS BETTER SFC DPT POOLING MECHANISMS.
LOCALLY IN SOUTHWEST SFC FLOW...SFC DPTS HAVING TROUBLE GETTING
OUT OF THE LOWER 60S WITH FETCH BACK INTO SIMILAR AIR MASS IN
NORTHEASTERN KS/FAR NW MO. CUT-OFF UPPER LOW ALMOST STACKED OVER
SFC FEATURE...WITH WATER VAPOR IMAGERY INDICATING NOSE OF MID/UPPER
LEVEL SPEED MAX PUSHING ACRS NORTHEASTERN KS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY MORNING)
ISSUED AT 248 PM CDT MON MAY 20 2013
TONIGHT...ASSESSING LOCAL INSTABILITY PARAMETERS...CAPES HAVE GROWN
TO ONLY 500 TO MAYBE 1000 J/KG ACRS PORTIONS OF THE DVN CWA...WITH
18Z SOUNDING SHOWING ROBUST H85 CAP/CONVECTIVE TEMP IN THE UPPER
80S. LACK OF AMBIENT CU LOCALLY A CLUE. DEEP UNIFORM SOUTHWESTERLIES
MAKING FOR MODERATE SHEAR/SPEED/ AT BEST. WITH MAIN VORT AND
MID/UPPER LEVEL VORT MAX STILL ACRS KS...DEEPER FORCING TO NOT
ARRIVE UNTIL MAINLY AFTER 00Z. THUS REST OF THIS AFTERNOON MAY SEE
A LACK OF CONVECTIVE ACTIVITY. WITH DEEP CONVECTIVE INDICE MAX
REALIGNING ACRS EASTERN KS INTO WESTERN/NORTHWEST MO THE REST OF THIS
AFTERNOON AND EARLY EVENING...EXPECT STORM DEVELOPMENT IN THESE
AREAS TO MOVE NORTHEAST AND BE THE SCTRD STORMS TO AFFECT PORTIONS
OF THE CWA THIS EVENING. THIS AND POSSIBLY SOME DEVELOPMENT AHEAD
OF THE WESTERN IA FRONT IN CU FIELD ONGOING OUT THERE ATTM. BUT
WITH YET UNFAVORABLE AIRMASS IN PLACE TO SUPPORT STRONG
CONVECTION...THIS ACTIVITY MAY WEAKEN AS IT ARRIVES UNLESS SOME
THERMODYNAMIC SUPPORT IS ADVECTED INTO THE AREA FROM THE
SOUTHWEST. MUCH UNCERTAINTY REGARDING THIS ATTM. IF STORMS DO
MAINTAIN AND MAKE IT INTO THE AREA...STILL A CHANCE FOR SOME SVR
CELLS LOOKING AT CURRENT AND PROGGED SHEAR PROFILES BUT MAIN
THREATS WOULD BE LARGE HAIL AND DAMAGING WIND GUSTS WITH ANY LINER/BOWING
DEVELOPMENT IN UNIFORM VERTICAL WIND FIELDS. LLVL SHEAR DIRECTION
AND HIGHER LCL/S OF AT LEAST 3K FT AGL CURRENTLY NOT THAT CONDUCIVE
FOR TORNADIC DEVELOPMENT. WILL KNOCK DOWN 00Z-06Z COVERAGE TO HIGH
CHC AND LIKELY POPS ACRS MOST OF THE DVN CWA...THEN WALK OUT ANY
LINGERING ACTIVITY AFTER 08Z FROM THE EASTERN CWA. LOCALLY HEAVY
RAINFALL BURSTS POSSIBLE...BUT MOVEMENT OF STORMS HOPEFULLY WILL
PRECLUDE MUCH OF ANY FLASH FLOOD THREAT UNLESS THE SAME AREA GETS
HIT REPEATEDLY AND HAD SIGNIFICANT RAIN LAST NIGHT. LOWS MAY DIP
INTO THE UPPER 50S IN THE NORTHWESTERN FCST AREA...BUT HELD IN THE
60S ELSEWHERE. ..12..
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY) ISSUED AT 248 PM CDT
MON MAY 20 2013
UPPER LOW OVER THE NORTHERN PLAINS TO GRADUALLY FILL AND SHIFT
EASTWARD THROUGH MIDWEEK...REPLACED BY HIGH PRESSURE AT THE SURFACE
AND MID LEVEL RIDGING. THIS WILL PROVIDE A CHANGE TO BELOW NORMAL
TEMPERATURES AND DRY WEATHER BY LATE WEEK. OVER THE WEEKEND...A
COOLER...UNSETTLED PATTERN DEVELOPS AS RETURNING MOISTURE INTERACTS
WITH A BOUNDARY OVER THE AREA.
TUESDAY...SURFACE LOW GRADUALLY EJECTS EASTWARD INTO THE UPPER MS
VALLEY. THIS WILL SEND THE OCCLUDED FRONT EASTWARD THROUGH THE
FORECAST AREA IN THE MORNING...THEN A SECONDARY TROUGH IS INDICATED
BY THE NAM DURING PEAK HEATING. EACH OF THESE FEATURES WILL POSSIBLY
TRIGGER SHOWERS AND THUNDERSTORMS...BUT WITH LOW CONFIDENCE IN
THE TIMING...STRENGTH...OR AVAILABLE INSTABILITY WITH THESE
FEATURES...HAVE ONLY CHANCE POPS THROUGH THE DAY. SUPPORT FOR SEVERE
STORMS IS LACKING DUE TO LESS FAVORABLE SHEAR PROFILES AND LIKELY
LESS AVAILABLE INSTABILITY THAN THE PAST COUPLE DAYS. COOLER
TEMPERATURES AT 850 MB AND LIKELIHOOD OF MORE CLOUDS SHOULD LIMIT
HIGHS TO THE MID 70S WEST TO POSSIBLY MID 80S EAST.
TUESDAY NIGHT INTO WED...SURFACE LOW TRANSITIONING EASTWARD INTO THE
GREAT LAKES AND FILLING UPPER LOW MIGRATING OVERHEAD TO KEEP
CHANCES FOR MAINLY DIURNAL SHOWERS GOING WITH HIGHEST POPS IN THE
EAST. ADVECTION OF COOLER... DRIER AIR TO ALLOW MINS TO COOL INTO
THE 50S WITH WED HIGHS LIMITED TO THE UPPER 60S TO LOWER 70S.
THURSDAY AND FRIDAY...UPPER TROUGH ADVANCES EASTWARD ALLOWING
CANADIAN HIGH PRESSURE TO BUILD SOUTHEAST INTO THE GREAT LAKES.
HAVE TWEAKED TEMPERATURES DOWNWARD SOME TO LIMIT HIGHS TO THE 60S
AND POSSIBLY LOWER 70S FOR FRI...WHILE LOWS THURSDAY NIGHT SHOULD BE
WIDESPREAD IN THE 40S AS THE CENTER OF THE INCOMING RIDGE PASSES
OVERHEAD.
SATURDAY THROUGH MONDAY REMAINS A BELOW AVERAGE CONFIDENCE FORECAST
PERIOD AS THERE IS LITTLE AGREEMENT IN THE DETAILS OF RETURN
WARM...MOIST ADVECTION FLOW...THE ASSOCIATED BOUNDARY...AND WHERE
PRECIPITATION WILL SET UP. FOR NOW...A BLENDED APPROACH TO DIVERSE
SOLUTIONS WILL KEEP AN EXTENDED PERIOD OF CHANCE POPS WITH
TEMPERATURES GRADUALLY WARMING TO NEAR OR ABOVE NORMAL BY MONDAY
WHEN THE ODDS ARE GREATER THAT THE FRONT WILL HAVE LIFTED NORTH OF
THE AREA. SHEETS
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 644 PM CDT MON MAY 20 2013
MAIN CONCERN FOR TAFS IN THE NEXT 24 HOURS IS THUNDERSTORM CHANCES
TONIGHT. LOOK LIKE TWO CENTERS OF ACTION...CLUSTERS IN NORTHWEST
MISSOURI WHICH LOOK IN LINE TO IMPACT BRL AND MLI...AND ANOTHER IN
CENTRAL IOWA WHICH WOULD APPEAR HEADED NORTH AND WEST OF CID AND
DBQ AT THIS TIME. COLD FRONTAL PASSAGE PROGGED TOMORROW WILL
RESULT IN GRADUAL SHIFTING OF WIND FROM SOUTH TO WEST. WOLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...SHEETS
AVIATION...WOLF
000
FXUS63 KDVN 202026
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
326 PM CDT MON MAY 20 2013
.SYNOPSIS...
ISSUED AT 248 PM CDT MON MAY 20 2013
LATEST SFC ANALYSIS WAS INDICATING OCCLUDING CYCLONE COMPLEX ACRS
THE EASTERN SD/ND REGION...WITH LEAD FRONT PUSHING ACRS WESTERN IA
BUT BETTER COLD WRAP AROUND NOTED ACRS SD INTO CENTRAL NEB. THE
REGION HAS BEEN PRETTY MUCH BATHED IN PRESSURE RISES TODAY...BUT
FALLS INCREASING ACRS WESTERN AND NORTHWESTERN MO. MAIN WARM FRONT
ACRS CENTRAL MN...FAR NORTHERN WI INTO THE NORTHERN LOWER MI.
SECONDARY FRONT ACRS WESTERN OK...AND REMNANT OUTFLOW BOUNDARY
ACRS CENTRAL MO ACTING AS BETTER SFC DPT POOLING MECHANISMS.
LOCALLY IN SOUTHWEST SFC FLOW...SFC DPTS HAVING TROUBLE GETTING
OUT OF THE LOWER 60S WITH FETCH BACK INTO SIMILAR AIR MASS IN
NORTHEASTERN KS/FAR NW MO. CUT-OFF UPPER LOW ALMOST STACKED OVER
SFC FEATURE...WITH WATER VAPOR IMAGERY INDICATING NOSE OF MID/UPPER
LEVEL SPEED MAX PUSHING ACRS NORTHEASTERN KS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY MORNING)
ISSUED AT 248 PM CDT MON MAY 20 2013
TONIGHT...ASSESSING LOCAL INSTABILITY PARAMETERS...CAPES HAVE GROWN
TO ONLY 500 TO MAYBE 1000 J/KG ACRS PORTIONS OF THE DVN CWA...WITH
18Z SOUNDING SHOWING ROBUST H85 CAP/CONVECTIVE TEMP IN THE UPPER
80S. LACK OF AMBIENT CU LOCALLY A CLUE. DEEP UNIFORM SOUTHWESTERLIES
MAKING FOR MODERATE SHEAR/SPEED/ AT BEST. WITH MAIN VORT AND
MID/UPPER LEVEL VORT MAX STILL ACRS KS...DEEPER FORCING TO NOT
ARRIVE UNTIL MAINLY AFTER 00Z. THUS REST OF THIS AFTERNOON MAY SEE
A LACK OF CONVECTIVE ACTIVITY. WITH DEEP CONVECTIVE INDICE MAX
REALIGNING ACRS EASTERN KS INTO WESTERN/NORTHWEST MO THE REST OF THIS
AFTERNOON AND EARLY EVENING...EXPECT STORM DEVELOPMENT IN THESE
AREAS TO MOVE NORTHEAST AND BE THE SCTRD STORMS TO AFFECT PORTIONS
OF THE CWA THIS EVENING. THIS AND POSSIBLY SOME DEVELOPMENT AHEAD
OF THE WESTERN IA FRONT IN CU FIELD ONGOING OUT THERE ATTM. BUT
WITH YET UNFAVORABLE AIRMASS IN PLACE TO SUPPORT STRONG
CONVECTION...THIS ACTIVITY MAY WEAKEN AS IT ARRIVES UNLESS SOME
THERMODYNAMIC SUPPORT IS ADVECTED INTO THE AREA FROM THE
SOUTHWEST. MUCH UNCERTAINTY REGARDING THIS ATTM. IF STORMS DO
MAINTAIN AND MAKE IT INTO THE AREA...STILL A CHANCE FOR SOME SVR
CELLS LOOKING AT CURRENT AND PROGGED SHEAR PROFILES BUT MAIN
THREATS WOULD BE LARGE HAIL AND DAMAGING WIND GUSTS WITH ANY LINER/BOWING
DEVELOPMENT IN UNIFORM VERTICAL WIND FIELDS. LLVL SHEAR DIRECTION
AND HIGHER LCL/S OF AT LEAST 3K FT AGL CURRENTLY NOT THAT CONDUCIVE
FOR TORNADIC DEVELOPMENT. WILL KNOCK DOWN 00Z-06Z COVERAGE TO HIGH
CHC AND LIKELY POPS ACRS MOST OF THE DVN CWA...THEN WALK OUT ANY
LINGERING ACTIVITY AFTER 08Z FROM THE EASTERN CWA. LOCALLY HEAVY
RAINFALL BURSTS POSSIBLE...BUT MOVEMENT OF STORMS HOPEFULLY WILL
PRECLUDE MUCH OF ANY FLASH FLOOD THREAT UNLESS THE SAME AREA GETS
HIT REPEATEDLY AND HAD SIGNIFICANT RAIN LAST NIGHT. LOWS MAY DIP
INTO THE UPPER 50S IN THE NORTHWESTERN FCST AREA...BUT HELD IN THE
60S ELSEWHERE. ..12..
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY) ISSUED AT 248 PM CDT
MON MAY 20 2013
UPPER LOW OVER THE NORTHERN PLAINS TO GRADUALLY FILL AND SHIFT
EASTWARD THROUGH MIDWEEK...REPLACED BY HIGH PRESSURE AT THE SURFACE
AND MID LEVEL RIDGING. THIS WILL PROVIDE A CHANGE TO BELOW NORMAL
TEMPERATURES AND DRY WEATHER BY LATE WEEK. OVER THE WEEKEND...A
COOLER...UNSETTLED PATTERN DEVELOPS AS RETURNING MOISTURE INTERACTS
WITH A BOUNDARY OVER THE AREA.
TUESDAY...SURFACE LOW GRADUALLY EJECTS EASTWARD INTO THE UPPER MS
VALLEY. THIS WILL SEND THE OCCLUDED FRONT EASTWARD THROUGH THE
FORECAST AREA IN THE MORNING...THEN A SECONDARY TROUGH IS INDICATED
BY THE NAM DURING PEAK HEATING. EACH OF THESE FEATURES WILL POSSIBLY
TRIGGER SHOWERS AND THUNDERSTORMS...BUT WITH LOW CONFIDENCE IN
THE TIMING...STRENGTH...OR AVAILABLE INSTABILITY WITH THESE
FEATURES...HAVE ONLY CHANCE POPS THROUGH THE DAY. SUPPORT FOR SEVERE
STORMS IS LACKING DUE TO LESS FAVORABLE SHEAR PROFILES AND LIKELY
LESS AVAILABLE INSTABILITY THAN THE PAST COUPLE DAYS. COOLER
TEMPERATURES AT 850 MB AND LIKELIHOOD OF MORE CLOUDS SHOULD LIMIT
HIGHS TO THE MID 70S WEST TO POSSIBLY MID 80S EAST.
TUESDAY NIGHT INTO WED...SURFACE LOW TRANSITIONING EASTWARD INTO THE
GREAT LAKES AND FILLING UPPER LOW MIGRATING OVERHEAD TO KEEP
CHANCES FOR MAINLY DIURNAL SHOWERS GOING WITH HIGHEST POPS IN THE
EAST. ADVECTION OF COOLER... DRIER AIR TO ALLOW MINS TO COOL INTO
THE 50S WITH WED HIGHS LIMITED TO THE UPPER 60S TO LOWER 70S.
THURSDAY AND FRIDAY...UPPER TROUGH ADVANCES EASTWARD ALLOWING
CANADIAN HIGH PRESSURE TO BUILD SOUTHEAST INTO THE GREAT LAKES.
HAVE TWEAKED TEMPERATURES DOWNWARD SOME TO LIMIT HIGHS TO THE 60S
AND POSSIBLY LOWER 70S FOR FRI...WHILE LOWS THURSDAY NIGHT SHOULD BE
WIDESPREAD IN THE 40S AS THE CENTER OF THE INCOMING RIDGE PASSES
OVERHEAD.
SATURDAY THROUGH MONDAY REMAINS A BELOW AVERAGE CONFIDENCE FORECAST
PERIOD AS THERE IS LITTLE AGREEMENT IN THE DETAILS OF RETURN
WARM...MOIST ADVECTION FLOW...THE ASSOCIATED BOUNDARY...AND WHERE
PRECIPITATION WILL SET UP. FOR NOW...A BLENDED APPROACH TO DIVERSE
SOLUTIONS WILL KEEP AN EXTENDED PERIOD OF CHANCE POPS WITH
TEMPERATURES GRADUALLY WARMING TO NEAR OR ABOVE NORMAL BY MONDAY
WHEN THE ODDS ARE GREATER THAT THE FRONT WILL HAVE LIFTED NORTH OF
THE AREA. SHEETS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1243 PM CDT MON MAY 20 2013
HAVE PUSHED BACK STORM DEVELOPMENT TIME AT CID AND DBQ TIL LATE
AFTERNOON...BRL AND MLI TO 20Z TO 21Z. BUT SOME SIGNS MOST OF THE
TERMINALS WILL BE VFR THROUGH 00Z IF STORM CLUSTERS DON/T DEVELOP
OUT OF NORTHEAST MO OR SOUTHEASTERN IA THIS AFTERNOON AND THEN
MOVE TOWARD BRL AND MLI. IF AFTERNOON STORMS DON/T DEVELOP OR STAY
SOUTH/EAST OF THE TERMINALS...BEST CHANCE WILL COME LATER THIS
EVENING AFTER 01Z AS MAIN FRONT APPROACHES FROM THE WEST. THESE
STORMS COULD BE STRONG TO SVR TOO WITH DAMAGING WIND AND HAIL...BUT
ADEQUATE INSTABILITY QUESTIONS FOR BOTH THIS AFTERNOON AND EVENING
CONTINUE WITH SFC DPTS STRUGGLING TO GET OUT OF THE LOWER 60S.
OTHERWISE GOOD VISIBILITY THIS AFTERNOON WITH MAINLY CLR SKIES OR
HIGH CLOUD BLOW OFF FROM STORMS IN MO. SOUTHWEST WINDS AT 10 TO 20
KTS WITH SOME HIGHER GUSTS...TO BECOME SOUTH SOUTHWEST OVERNIGHT
WITHOUT THE GUSTS. BUT STILL A CHANCE FOR VARIABLE GUSTS OVER
35-40 KTS WITH THE EVENING LINE OF STORMS. SOME MVFR FOG POSSIBLE
TOWARD SUNRISE BEFORE SOUTHWEST WINDS INCREASE AGAIN BY MID TUE MORNING.
12
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...12
SHORT TERM...12
LONG TERM...SHEETS
AVIATION...12
000
FXUS63 KDVN 201754
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1254 PM CDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1104 AM CDT MON MAY 20 2013
QUICK ASSESSMENT ON THIS MORNINGS UPPER AIR ANALYSIS AND WHAT IS
TAKING PACE CURRENTLY...SEEMS THERE MAY BE A DELAY TO LATER THIS
AFTERNOON AND EARLY EVENING. CURRENT TEMPS IN THE LOW TO MID 70S
WITH SFC DPTS MAINLY IN THE LOW 60S WILL STILL TAKE TIME TO
IMPROVE UPON...ESPECIALLY WITH BETTER SFC MOISTURE POOLED ALONG
OUTFLOW BOUNDARY ACRS CENTRAL MO ATTM. THE LOCAL AREA UNDER A H85
MB AND H7 MB LULL IN MOISTURE AS WELL. MID AND UPPER JET MAX/S
ACRS THE GRT BSN AND SHIFTING INTO THE SOUTHWESTERN PLAINS THIS
MORNING WILL NOT NOSE UP ACRS THE CWA UNTIL AFTER 20Z-21Z THIS
AFTERNOON. IF SFC DPTS ONLY RECOVER INTO THE MID 60S...THE 12Z NAM
AND GFS PROGGED CAPES OF 1500-2000 J/KG MAY BE TOO HIGH. ALSO HIGH
TEMPS MAY BE MORE IN THE WAY OF LOW TO MID 80S AS OPPOSED TO MID
TO UPPER 80S THIS AFTERNOON. SFC WINDS CURRENTLY SOUTH AND MAINLY
SOUTHWESTERLY...THUS WITHOUT AND LLVL BACKING TO THE SOUTHEAST THE
LOWER LEVEL HELICITIES AND SHEAR DON/T APPEAR AS IMPRESSIVE AS
WHAT MAY BE EARLIER THOUGHT. BUT THERE APPEARS TO BE DECENT DEEPER
LAYER SPEED SHEAR WITH UNIFORM VERTICAL PROFILES. LCL LEVELS MAY
NOT BE AS LOW AS WHAT THE SHORT RANGE MODELS DEPICT IN THE
SOUTHEAST THIRD/1500-2000 FT AGL/ THIS AFTERNOON AS WELL LIMITING
A POSSIBLE TORNADIC THREAT. THUS ALL IN ALL...LESS INSTABILITY
BUT STILL STRONG KINEMATICS/SHEAR SUGGEST A THREAT FOR LARGE HAIL
AND DAMAGING DOWNBURST WINDS WITH STILL THE POSSIBILITY OF
SUPERCELL TYPE DISCRETE STORMS THIS AFTERNOON...BUT MAY BE LESS
WIDESPREAD THEN YESTERDAY. THE SOUTHEAST THIRD OF THE CWA MOST AT
RISK OF SVR STORMS THIS AFTERNOON. STILL CAN/T RULE OUT ISOLATED
TORNADOES AND ANY WATCH THAT DOES COME OUT WILL PROBABLY STILL BE
A TOR WATCH FOR THE LOCAL AREA. SECOND ROUND OF STORMS ALONG THE
MAIN FRONT ITSELF...CURRENTLY ACRS FAR WESTERN IA...MAY SWEEP ACRS
THE AREA FROM THE WEST NOT UNTIL MID EVENING. WILL STILL HAVE TO
BE VERY MUCH ON GUARD AND WATCH TRENDS THROUGH THE AFTERNOON.
12
&&
.SYNOPSIS...
ISSUED AT 304 AM CDT MON MAY 20 2013
06Z SFC ANALYSIS HAS A SYNOPTIC LOW NEAR KMBG WITH THE STATIONARY
FRONT RUNNING EAST THROUGH WISCONSIN AND LOWER MICHIGAN. MESOSCALE
LOWS WERE NEAR KFSD...KBVN...AND KCSM. NUMEROUS OUTFLOW BOUNDARIES
RAN FROM ILLINOIS BACK THROUGH MISSOURI. DEW POINTS WERE IN THE 50S
AND 60S ACROSS THE MIDWEST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 304 AM CDT MON MAY 20 2013
TODAY WILL BE QUITE INTERESTING. MESOSCALE PROCESSES WILL DRIVE THE
SENSIBLE WX AND CONCEPTUALLY...THERE IS A GOOD PROBABILITY OF SEEING
SEVERE STORMS THIS AFTERNOON AND EVENING.
MCS AND LIFT TOOLS SUGGEST THE BULK OF THE MCS MOVING ACROSS MISSOURI
WILL REMAIN SOUTH OF THE AREA. HOWEVER...VORT MAXES HELPING TO DRIVE
THIS MCS WILL PUSH DECAYING SHRA AND SOME TSRA INTO THE CWFA THROUGH
SUNRISE WITH ACTIVITY DISSIPATING DURING THE MORNING.
THERE SHOULD BE A FEW HOURS OF QUIET WX FROM MID TO LATE MORNING
UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED. ONCE THIS OCCURS...NEW
CONVECTION WILL DEVELOP DURING THE AFTERNOON AND BUILD INTO ONE OR
MORE SEVERE MESOSCALE CONVECTIVE COMPLEXES BY EARLY EVENING.
THE OVERALL PLACEMENT OF THE JET STRUCTURE AND INSTABILITY AXIS
POINT TO SEVERE STORMS DEVELOPING DURING THE AFTERNOON. LARGE HAIL
AND DAMAGING WINDS ARE A GIVEN. THE SHEAR PROFILES AND BUOYANCY IS
ALSO FAVORABLE FOR TORNADOES...POSSIBLY SIGNIFICANT.
BY LATE EVENING AND OVERNIGHT...STORM ACTIVITY WILL BE ON THE
DECREASE AS THE ATMOSPHERE COOLS.
08
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON MAY 20 2013
TURNING COOLER AND UNSETTLED WITH PROBABLY COOL RAINS AGAIN THIS NEXT
WEEKEND.
OVERVIEW...INITIALIZATION AND VERIFICATION ON LARGER SCALES...OR
SYNOPTIC SCALE ARE GOOD BUT ALL SOLUTIONS POOR TO VERY POOR ON
PRECIPITATION/MOISTURE/CLOUDS. AGAIN HEAVY USE OF CONCEPTUAL FORCING
TOOLS WHICH HAS AIDED PAST SEVERAL DAYS. THIS SUPPORTS MORE SHOWERS
AND STORMS TUESDAY TURNING COOLER WITH CLOUDS AND SHOWERS WEDNESDAY.
RISK OF SEVERE TUESDAY IS QUESTIONABLE BASED ON CONVECTION AND NEXT
WAVE INTERACTIONS LATER ON TUESDAY. PREFER A 60/40 MIX OF FORCING
OF HI-RES ECMWF AND NAM-WRF INTO DAY 4...THEN A 50/50 OF HI-RES
ECMWF AND GFS DAY 4 AND BEYOND.
TUESDAY...POOR CONFIDENCE IN FORECAST POPS AS NEXT 24 HOURS WILL
IMPACT EVOLUTION OF UPPER LOW AND PROGRESS OF COOL FRONT AND
ASSOCIATED AMOUNT OF CLEARING/CLOUDS. UPPER JET SUPPORTS LIGHTER AND
LOWER POPS WEST WITH RISK OF LINGERING WAVE OF SHOWERS AND STORMS
THAT SHOULD TEND TO STAY BELOW SEVERE LEVELS. HIGHS 75 TO 80 FROM
NW TO SE. MINS MID 50S NW TO THE LOWER 60S SE SECTIONS.
WEDNESDAY...CLOUDY AND COOLER WITH RAIN OR RAIN SHOWERS. HIGHS IN
THE NORTH MAY NEED LOWERING WITH LOW CLOUDS AND POSSIBLY EVEN
DRIZZLE WITH COOL NORTH WINDS ARRIVING FROM NORTH TO SOUTH DURING
THE DAY A BIT EARLIER IN THE FORECAST FOR LATER SHIFTS. WEDNESDAY
NIGHT...LOW CLOUDS AND POSSIBLY LIGHT RAIN AND PROBABLY AREAS OF
DRIZZLE WITH MINS IN THE 50S.
THURSDAY AND FRIDAY...BELOW NORMAL TEMPERATURES MOSTLY IN 65 TO
72 DEGREE RANGE. CLOUDS WILL CLEAR IN THE AFTERNOON FROM NORTH TO
SOUTH AS CANADIAN HIGH PRESSURE MOVES IN. THURSDAY NIGHT...CLEAR
AND COOL WITH MINS PROBABLY MANY LOCATIONS 3+ DEGREES TOO MILD WITH
LOWER TO MIDDLE 40S SUGGESTED OVER NORTH SECTIONS. FRIDAY...SUNNY
AND COOL WITH LIGHT NE WINDS.
SATURDAY AND SUNDAY...WESTERLY WINDS TO UPGLIDE OVER COOL AIRMASS
THAT PRIMES THE REGION FOR COOL HIGHS DUE TO GOOD EVAPORATIVE
COOLING AND LIKELY RAIN AND ISOLATED STORMS POSSIBLE IN SOUTH AND
WEST SECTIONS. CHANCE POPS FOR NOW WILL LIKELY BE RAISED WITH
TIMING ISSUES BETTER CLARIFIED. ANOTHER MODERATE TO LOCALLY LOWER
END HEAVY RAIN EVENT WITH MOST AREAS PICKING UP .5 TO 1+ INCHES.
NICHOLS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1243 PM CDT MON MAY 20 2013
HAVE PUSHED BACK STORM DEVELOPMENT TIME AT CID AND DBQ TIL LATE
AFTERNOON...BRL AND MLI TO 20Z TO 21Z. BUT SOME SIGNS MOST OF THE
TERMINALS WILL BE VFR THROUGH 00Z IF STORM CLUSTERS DON/T DEVELOP
OUT OF NORTHEAST MO OR SOUTHEASTERN IA THIS AFTERNOON AND THEN
MOVE TOWARD BRL AND MLI. IF AFTERNOON STORMS DON/T DEVELOP OR STAY
SOUTH/EAST OF THE TERMINALS...BEST CHANCE WILL COME LATER THIS
EVENING AFTER 01Z AS MAIN FRONT APPROACHES FROM THE WEST. THESE
STORMS COULD BE STRONG TO SVR TOO WITH DAMAGING WIND AND HAIL...BUT
ADEQUATE INSTABILITY QUESTIONS FOR BOTH THIS AFTERNOON AND EVENING
CONTINUE WITH SFC DPTS STRUGGLING TO GET OUT OF THE LOWER 60S.
OTHERWISE GOOD VISIBILITY THIS AFTERNOON WITH MAINLY CLR SKIES OR
HIGH CLOUD BLOW OFF FROM STORMS IN MO. SOUTHWEST WINDS AT 10 TO 20
KTS WITH SOME HIGHER GUSTS...TO BECOME SOUTH SOUTHWEST OVERNIGHT
WITHOUT THE GUSTS. BUT STILL A CHANCE FOR VARIABLE GUSTS OVER
35-40 KTS WITH THE EVENING LINE OF STORMS. SOME MVFR FOG POSSIBLE
TOWARD SUNRISE BEFORE SOUTHWEST WINDS INCREASE AGAIN BY MID TUE MORNING.
12
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...12
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...12
000
FXUS63 KDVN 201630
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1130 AM CDT MON MAY 20 2013
.UPDATE...
ISSUED AT 1104 AM CDT MON MAY 20 2013
QUICK ASSESSMENT ON THIS MORNINGS UPPER AIR ANALYSIS AND WHAT IS
TAKING PACE CURRENTLY...SEEMS THERE MAY BE A DELAY TO LATER THIS
AFTERNOON AND EARLY EVENING. CURRENT TEMPS IN THE LOW TO MID 70S
WITH SFC DPTS MAINLY IN THE LOW 60S WILL STILL TAKE TIME TO
IMPROVE UPON...ESPECIALLY WITH BETTER SFC MOISTURE POOLED ALONG
OUTFLOW BOUNDARY ACRS CENTRAL MO ATTM. THE LOCAL AREA UNDER A H85
MB AND H7 MB LULL IN MOISTURE AS WELL. MID AND UPPER JET MAX/S
ACRS THE GRT BSN AND SHIFTING INTO THE SOUTHWESTERN PLAINS THIS
MORNING WILL NOT NOSE UP ACRS THE CWA UNTIL AFTER 20Z-21Z THIS
AFTERNOON. IF SFC DPTS ONLY RECOVER INTO THE MID 60S...THE 12Z NAM
AND GFS PROGGED CAPES OF 1500-2000 J/KG MAY BE TOO HIGH. ALSO HIGH
TEMPS MAY BE MORE IN THE WAY OF LOW TO MID 80S AS OPPOSED TO MID
TO UPPER 80S THIS AFTERNOON. SFC WINDS CURRENTLY SOUTH AND MAINLY
SOUTHWESTERLY...THUS WITHOUT AND LLVL BACKING TO THE SOUTHEAST THE
LOWER LEVEL HELICITIES AND SHEAR DON/T APPEAR AS IMPRESSIVE AS
WHAT MAY BE EARLIER THOUGHT. BUT THERE APPEARS TO BE DECENT DEEPER
LAYER SPEED SHEAR WITH UNIFORM VERTICAL PROFILES. LCL LEVELS MAY
NOT BE AS LOW AS WHAT THE SHORT RANGE MODELS DEPICT IN THE
SOUTHEAST THIRD/1500-2000 FT AGL/ THIS AFTERNOON AS WELL LIMITING
A POSSIBLE TORNADIC THREAT. THUS ALL IN ALL...LESS INSTABILITY
BUT STILL STRONG KINEMATICS/SHEAR SUGGEST A THREAT FOR LARGE HAIL
AND DAMAGING DOWNBURST WINDS WITH STILL THE POSSIBILITY OF
SUPERCELL TYPE DISCRETE STORMS THIS AFTERNOON...BUT MAY BE LESS
WIDESPREAD THEN YESTERDAY. THE SOUTHEAST THIRD OF THE CWA MOST AT
RISK OF SVR STORMS THIS AFTERNOON. STILL CAN/T RULE OUT ISOLATED
TORNADOES AND ANY WATCH THAT DOES COME OUT WILL PROBABLY STILL BE
A TOR WATCH FOR THE LOCAL AREA. SECOND ROUND OF STORMS ALONG THE
MAIN FRONT ITSELF...CURRENTLY ACRS FAR WESTERN IA...MAY SWEEP ACRS
THE AREA FROM THE WEST NOT UNTIL MID EVENING. WILL STILL HAVE TO
BE VERY MUCH ON GUARD AND WATCH TRENDS THROUGH THE AFTERNOON.
12
UPDATE ISSUED AT 624 AM CDT MON MAY 20 2013
THE NOCTURNAL MCS WILL CONTINUE TO SLOWLY DISSIPATE THROUGH MID
MORNING AND MOST OF THE AREA SHOULD SEE DRY CONDITIONS THROUGH MID
DAY. AFTER MID DAY NEW CONVECTION WILL RAPIDLY DEVELOP ONCE
CONVECTIVE TEMPERATURE IS ACHIEVED.
DATA INDICATES DISCRETE CELLS WILL INITIALLY DEVELOP THAT EVOLVE
INTO ONE OR MORE LINEAR MCS EVENTS BY EARLY EVENING AND WILL
CONTINUE INTO THE LATE EVENING.
THERE IS STILL A GOOD POTENTIAL FOR SEVERE STORMS THIS AFTERNOON
AND EVENING. THE MORNING UA FLIGHT THAT IS UNDERWAY SHOWS
CONSIDERABLE SPEED SHEAR UP THROUGH 2KFT AGL. THE KEY TO
EVERYTHING WILL BE HOW THE UPPER JET ROTATING UP FROM THE SOUTHERN
PLAINS WILL INTERACT WITH LOWER LEVEL FEATURES.
BASED ON THE PROGGED PLACEMENT OF THE JET STRUCTURE AND
INSTABILITY AXIS...SEVERE STORMS APPEAR TO BE PROBABLE DURING THE
AFTERNOON AND EVENING HOURS. IF SEVERE STORMS OCCUR...DAMAGING
WINDS AND LARGE HAIL ARE A GIVEN. BASED ON PROGGED SHEAR PROFILES
AND BUOYANCY WITH INPUT FROM THE IN PROGRESS 12Z UA FLIGHT...
TORNADOES ARE ALSO POSSIBLE. IF TORNADOES DEVELOP WITH THE
DISCRETE CELLS...SIGNIFICANT TORNADOES MAY BE POSSIBLE. ..08..
&&
.SYNOPSIS...
ISSUED AT 304 AM CDT MON MAY 20 2013
06Z SFC ANALYSIS HAS A SYNOPTIC LOW NEAR KMBG WITH THE STATIONARY
FRONT RUNNING EAST THROUGH WISCONSIN AND LOWER MICHIGAN. MESOSCALE
LOWS WERE NEAR KFSD...KBVN...AND KCSM. NUMEROUS OUTFLOW BOUNDARIES
RAN FROM ILLINOIS BACK THROUGH MISSOURI. DEW POINTS WERE IN THE 50S
AND 60S ACROSS THE MIDWEST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 304 AM CDT MON MAY 20 2013
TODAY WILL BE QUITE INTERESTING. MESOSCALE PROCESSES WILL DRIVE THE
SENSIBLE WX AND CONCEPTUALLY...THERE IS A GOOD PROBABILITY OF SEEING
SEVERE STORMS THIS AFTERNOON AND EVENING.
MCS AND LIFT TOOLS SUGGEST THE BULK OF THE MCS MOVING ACROSS MISSOURI
WILL REMAIN SOUTH OF THE AREA. HOWEVER...VORT MAXES HELPING TO DRIVE
THIS MCS WILL PUSH DECAYING SHRA AND SOME TSRA INTO THE CWFA THROUGH
SUNRISE WITH ACTIVITY DISSIPATING DURING THE MORNING.
THERE SHOULD BE A FEW HOURS OF QUIET WX FROM MID TO LATE MORNING
UNTIL CONVECTIVE TEMPERATURE IS ACHIEVED. ONCE THIS OCCURS...NEW
CONVECTION WILL DEVELOP DURING THE AFTERNOON AND BUILD INTO ONE OR
MORE SEVERE MESOSCALE CONVECTIVE COMPLEXES BY EARLY EVENING.
THE OVERALL PLACEMENT OF THE JET STRUCTURE AND INSTABILITY AXIS
POINT TO SEVERE STORMS DEVELOPING DURING THE AFTERNOON. LARGE HAIL
AND DAMAGING WINDS ARE A GIVEN. THE SHEAR PROFILES AND BUOYANCY IS
ALSO FAVORABLE FOR TORNADOES...POSSIBLY SIGNIFICANT.
BY LATE EVENING AND OVERNIGHT...STORM ACTIVITY WILL BE ON THE
DECREASE AS THE ATMOSPHERE COOLS.
08
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 304 AM CDT MON MAY 20 2013
TURNING COOLER AND UNSETTLED WITH PROBABLY COOL RAINS AGAIN THIS NEXT
WEEKEND.
OVERVIEW...INITIALIZATION AND VERIFICATION ON LARGER SCALES...OR
SYNOPTIC SCALE ARE GOOD BUT ALL SOLUTIONS POOR TO VERY POOR ON
PRECIPITATION/MOISTURE/CLOUDS. AGAIN HEAVY USE OF CONCEPTUAL FORCING
TOOLS WHICH HAS AIDED PAST SEVERAL DAYS. THIS SUPPORTS MORE SHOWERS
AND STORMS TUESDAY TURNING COOLER WITH CLOUDS AND SHOWERS WEDNESDAY.
RISK OF SEVERE TUESDAY IS QUESTIONABLE BASED ON CONVECTION AND NEXT
WAVE INTERACTIONS LATER ON TUESDAY. PREFER A 60/40 MIX OF FORCING
OF HI-RES ECMWF AND NAM-WRF INTO DAY 4...THEN A 50/50 OF HI-RES
ECMWF AND GFS DAY 4 AND BEYOND.
TUESDAY...POOR CONFIDENCE IN FORECAST POPS AS NEXT 24 HOURS WILL
IMPACT EVOLUTION OF UPPER LOW AND PROGRESS OF COOL FRONT AND
ASSOCIATED AMOUNT OF CLEARING/CLOUDS. UPPER JET SUPPORTS LIGHTER AND
LOWER POPS WEST WITH RISK OF LINGERING WAVE OF SHOWERS AND STORMS
THAT SHOULD TEND TO STAY BELOW SEVERE LEVELS. HIGHS 75 TO 80 FROM
NW TO SE. MINS MID 50S NW TO THE LOWER 60S SE SECTIONS.
WEDNESDAY...CLOUDY AND COOLER WITH RAIN OR RAIN SHOWERS. HIGHS IN
THE NORTH MAY NEED LOWERING WITH LOW CLOUDS AND POSSIBLY EVEN
DRIZZLE WITH COOL NORTH WINDS ARRIVING FROM NORTH TO SOUTH DURING
THE DAY A BIT EARLIER IN THE FORECAST FOR LATER SHIFTS. WEDNESDAY
NIGHT...LOW CLOUDS AND POSSIBLY LIGHT RAIN AND PROBABLY AREAS OF
DRIZZLE WITH MINS IN THE 50S.
THURSDAY AND FRIDAY...BELOW NORMAL TEMPERATURES MOSTLY IN 65 TO
72 DEGREE RANGE. CLOUDS WILL CLEAR IN THE AFTERNOON FROM NORTH TO
SOUTH AS CANADIAN HIGH PRESSURE MOVES IN. THURSDAY NIGHT...CLEAR
AND COOL WITH MINS PROBABLY MANY LOCATIONS 3+ DEGREES TOO MILD WITH
LOWER TO MIDDLE 40S SUGGESTED OVER NORTH SECTIONS. FRIDAY...SUNNY
AND COOL WITH LIGHT NE WINDS.
SATURDAY AND SUNDAY...WESTERLY WINDS TO UPGLIDE OVER COOL AIRMASS
THAT PRIMES THE REGION FOR COOL HIGHS DUE TO GOOD EVAPORATIVE
COOLING AND LIKELY RAIN AND ISOLATED STORMS POSSIBLE IN SOUTH AND
WEST SECTIONS. CHANCE POPS FOR NOW WILL LIKELY BE RAISED WITH
TIMING ISSUES BETTER CLARIFIED. ANOTHER MODERATE TO LOCALLY LOWER
END HEAVY RAIN EVENT WITH MOST AREAS PICKING UP .5 TO 1+ INCHES.
NICHOLS
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 624 AM CDT MON MAY 20 2013
NOCTURNAL CONVECTION IS DISSIPATING ACRS IOWA/ILLINOIS AND SHOULD
BE GONE BY 15Z/20. MORNING UPPER AIR FLIGHT HAS 40 KTS JUST OFF
THE SURFACE SO LLWS WAS INCLUDED IN ALL TAFS UNTIL THE INVERSION
BREAKS AROUND 15Z/20. OTHERWISE VFR CONDITIONS WILL BE SEEN
THROUGH 18Z/20. AFT 18Z/20 NEW CONVECTION WILL DVLP RAPIDLY WITH
SEVERE STORMS POSSIBLE. PROBABILITY IS HIGH THAT MVFR/IFR
CONDITIONS WITH G40 KTS WILL BE SEEN IF A TSRA AFFECTS A TAF SITE.
CONVECTION WILL CONTINUE PAST 00Z/21 WITH INCREASING PROBABILITY
OF MVFR CONDITIONS. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...12
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...08
| 
