Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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121
FXUS63 KDVN 032034
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
334 PM CDT TUE MAY 3 2016

.SYNOPSIS...
ISSUED AT 330 PM CDT TUE MAY 3 2016

THE LATEST SFC ANALYSIS WAS INDICATING A LOW PRESSURE SYSTEM PASSING
NORTHEAST OF THE GRT LKS...WHILE A SOUTHWESTWARD TRAILING COLD
FRONT EXTENDED BACK ACRS CENTRAL MN INTO NORTHERN SD. WIDESPREAD
CELLULAR CU FIELD HAS POPPED UP IN THIS SYSTEM/S BREEZY WARM
SECTOR...BUT LOOKS TO ALSO HAVE ZAPPED THE HIGH TEMP POTENTIAL BY A
FEW DEGREES. MAY HAVE TO WATCH FOR AN ISOLATED SHOWER DEVELOPING IN
THIS CU FIELD ESPECIALLY IN NORTHWESTERN IL THRU 00Z. ALOFT...12Z
UPPER AIR ANALYSIS WAS INDICATING UPSTREAM WELL PRONOUNCED OMEGA
BLOCK RIDGE COMPLEX ACRS THE ROCKIES...WHILE A RATHER VIGOROUS VORT
MAX WAS NOTED ON THE LATEST WATER VAPOR IMAGERY DIGGING SOUTH OUT OF
ONTARIO AND INTO THE GRT LKS.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT TUE MAY 3 2016

TONIGHT...THE UPSTREAM FRONT TO THE NORTH ACRS MN INTO FAR NW WI/MI
U.P. AND ASSOCIATED BAND OF ELEVATED SHOWERS...WILL WORK IT/S WAY
DOWN THROUGH THE LOCAL AREA AS THE EVENING PROGRESSES. WILL BRING IT
DOWN TO A CID TO DBQ LINE BY 9 PM CDT...ALONG AND NORTH OF I80 BY
11 PM CDT...AND DOWN INTO THE SOUTHEASTERN THIRD OF THE CWA BY 1 AM
WITH EYES ON EXITING THE AREA BY 2-3 AM CDT WED MORNING.  THIS
PROGRESSIVE BAND SHOULD NOT LINGER MUCH LONGER THAN 2-3 HRS AT ANY
ONE POINT AND MOST AREAS EXPECTED TO GET A QUARTER INCH OR LESS
OF RAINFALL BY THE TIME IT MOVES OUT...MOST AREAS PROBABLY 0.15 OF
AN INCH OR LESS. LITTLE OR NO LIGHTNING INDICATED ON SENSORS ATTM
UPSTREAM TO THE NORTH AND WONDERING IF WE WILL EXPERIENCE MUCH
THUNDER AT ALL OVERNIGHT WITH LESS THAN AN OPTIMUM TIME OF DAY TO
MAKE IT/S WAY THROUGH. BUT SEVERAL MODELS STILL ADVECT A PLUME OF
6.5 TO 7 C/KM MID LAYER LAPSE RATES DOWN ACRS THE AREA FROM 01Z TO
07Z WED...AS WELL AS MUCAPES OF 100-200+ IN THAT SAME LAYER. THUS
WILL KEEP AT LEAST ISOLATED THUNDER MENTION GOING IN MOST AREAS.
THE FAR SOUTH MAY BE MARGINAL FOR MUCH LIGHTNING/WEAKENING UPDRAFT
PERCULATIONS BY THE TIME IT GETS DOWN THERE AFTER MIDNIGHT LOOKING
AT THE FCST SOUNDINGS AT THAT TIME. POST-FRONTAL VEERING OF WEST
WINDS TO THE NORTH WITH SOME INCREASE INTO EARLY WED MORNING TO
COOL ADVECT INTO SUNRISE. BUT MIXING WINDS THEMSELVES OF 10-15 MPH
SHOULD KEEP LOWS IN MOST AREAS/EXCEPT THE FAR NORTH/ IN THE MID TO
UPPER 40S. IF THE WINDS WERE TO DECOUPLE AT THE SFC...EXTENT OF
COOLING AIRMASS FLOWING DOWN INTO THE REGION WOULD SUPPORT MORE LOWS
IN THE 30S AGAIN BY 12Z WED.

WEDNESDAY...STEEP NEAR MERIDIONAL FLOW WILL DUMP DOWN THE UPPER TO
MID MS RVR VALLEY/WESTERN OH RVR VALLEY...ALONG WITH BREEZY POST-
FRONTAL COOLING CONDITIONS LOCALLY. FCST HIGHS OF UPPER 50S TO LOW
60S ACRS MUCH OF THE DVN CWA WILL NEED DEEP MIXING UP ABOVE H85 MB
TO GET THOSE VALUES...AND MORE CELLULAR CU WILL ALSO ACT AS A
THERMAL ROBBER ESPECIALLY ALONG AND EAST OF THE MS RVR. ISOLATED
POP-UP INSTABILITY SHOWERS ALSO POSSIBLE MAINLY EAST OF THE MS RVR
BY WED AFTERNOON. NORTH TO NORTHWEST WINDS MAY GUST OVER 30 MPH AT
TIMES IN PRIME MIX-OUT WINDOW.    ..12..


.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 330 PM CDT TUE MAY 3 2016

FORECAST FOCUS ON WARMER TEMPERATURES WITH CHANCES OF RAIN
ESPECIALLY EARLY NEXT WEEK.

WEDNESDAY NIGHT...WEAK HIGH PRESSURE RIDGE WILL STILL BE WEST OF THE
DVN CWA WHICH SHOULD ALLOW ENOUGH OF A WIND TO PREVENT WIDESPREAD
FROST. SKIES LOOK TO BE CLEAR MUCH OF THE NIGHT WITH MINIMUM
TEMPERATURES RANGING FROM THE UPPER 30S NORTH TO THE LOWER 40S
SOUTH. PATCHY FROST IS STILL POSSIBLE IN THE NORTH EARLY THURSDAY
BUT WON`T MENTION IN THE GRIDS JUST YET. THE MORE FAVORED AREAS FOR
ANY FROST WOULD BE VALLEY OR SHELTERED SPOTS AWAY FROM THE WIND.

THURSDAY...THE RIDGE AXIS WILL SHIFT INTO THE CWA WITH PLENTY OF
SUNSHINE AND LIGHT NORTHWEST WINDS. MAXIMUM TEMPERATURES SHOULD BE
GETTING CLOSER TO NORMAL WITH HIGHS IN THE 60S.

FRIDAY...SOUTHERLY WINDS ON THE BACK SIDE OF THE HIGH AND PLENTY OF
SUNSHINE WILL PUSH TEMPERATURES TO ABOVE NORMAL FOR A CHANGE. HIGHS
SHOULD BE AROUND 80 AT MOST LOCATIONS.

SATURDAY THROUGH SUNDAY...UPPER LEVEL TROUGH SWINGING THROUGH THE
GREAT LAKES WILL SEND A COLD FRONT INTO THE CWA IN THE AFTERNOON...
ACCOMPANIED BY SCATTERED SHOWERS AND A FEW THUNDERSTORMS. THE FRONT
WILL SLIDE SOUTHWARD ON SATURDAY NIGHT INTO OUR FAR SOUTH ENDING THE
RAIN CHANCES WITH THE PASSAGE OF THE FRONT. THE MODELS ARE DRYING
SUNDAY OUT COMPARED TO PREVIOUS MODEL RUNS BUT THE CONSENSUS MODELS
STILL HANG ONTO SMALL POPS IN OUR FAR SOUTH. LATER SHIFTS CAN REMOVE
THESE POPS IF THIS DRIER TREND CONTINUES. HIGHS WILL BE IN THE 70S
ON SATURDAY DROPPING INTO THE UPPER 60S ON SUNDAY.

EARLY NEXT WEEK...THE MAIN UPPER LEVEL TROUGH AND LARGE SCALE ASCENT
IS EXPECTED TO ARRIVE DURING THIS TIME FRAME. ECMWF/GFS WANT TO KEY
ON TUESDAY FOR THE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS.
HOWEVER...WILL KEEP HIGH-END CHANCE POPS FOR NOW AS CONFIDENCE IN
THE TIMING NOT QUITE THERE YET SO PLENTY OF ROOM TO RAISE POPS LATER.
MAXIMUM TEMPERATURES WILL BE IN THE LOWER 70S AT MOST LOCATIONS.

HAASE

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1245 PM CDT TUE MAY 3 2016

CELLULAR INSTABILITY CU HAS REALLY BLOSSOMED TO SCTRD AND BKN
COVERAGE ACRS THE AREA...BUT AT VFR HEIGHTS. WILL NOT INCLUDE IN
THE TAFS AT THIS POINT...BUT AN ISOLATED HIGH BASED SHOWER
POSSIBLE IN THESE CU FIELDS THIS AFTERNOON ESPECIALLY IN THE
VCNTY OF DBQ AND MLI. BREEZY WEST WINDS GUSTING OVER 20 KTS NORTH
OF I80 THIS AFTERNOON. TONIGHT...A COLD FRONT WILL SLIP DOWN ACRS
THE AREA FROM THE NORTH AND SWEEP A BAND OF SHOWERS AND EMBEDDED
THUNDER ALONG WITH IT. HAVE TIMED THIS PRECIP WITH TEMPO GROUPS
FROM NORTH TO SOUTH IN THE TAFS. EXPECT THE SHOWERS TO REMAIN HIGH
BASED AND AT VFR LEVELS AS THEY PASS BY AT DURATIONS GENERALLY
AROUND 2-3 HRS AT ANY ONE POINT...BUT MAY HAVE FLEETING MVFR VSBYS
WITH THE HEAVIER DOWN POURS. THERE MAY BE SOME VARIABLE ENHANCED
WIND GUSTS WITH THE DOWNPOURS AS WELL. VEERING POST- FRONTAL WINDS
TO NORTHWEST OR EVEN NORTH BY LATE TONIGHT/EARLY WED MORNING.
..12..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...HAASE
AVIATION...12



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