Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 250858
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
358 AM CDT SAT APR 25 2015

.SYNOPSIS...
ISSUED AT 313 AM CDT SAT APR 25 2015

THE LATEST SFC ANALYSIS WAS INDICATING THE MAIN WRAPPED UP CYCLONE
CURRENTLY ACRS THE SOUTHEASTERN NEB/NE KS BORDER REGION...WHILE
WATER VAPOR IMAGERY AND LATEST UA ANALYSIS SHOWED THE WAVE ALOFT
STACKED ALMOST OVERHEAD IN THE SAME AREA. REGIONAL RADAR LOOPS
INDICATED A LARGE CYCLONICALLY ORIENTED CONVECTIVE COMPLEX
ASSOCIATED WITH THE MAIN SYSTEM OFF TO THE WEST/SOUTHWEST...BUT
SECONDARY CONVERGENT WARM AIR ADVECTION WING-FUELED PRECIP SWATH
WAS MOVING ACRS THE CENTRAL CWA ATTM ON NOSE OF IN-WRAPPING DRY
SLOT FROM THE SOUTH. BRISK EAST- NORTHEAST LLVL FLOW ADVECTING
COOL TEMPS INTO THE NORTHERN HALF OF THE CWA...WHILE AREAS IN THE
FAR SOUTH WITH MORE OF A SOUTHEAST COMPONENT ARE STILL IN THE 50S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT SAT APR 25 2015

TODAY...CLOSED UPPER LOW WILL LOOK TO DRIFT EASTWARD ALONG AND
JUST SOUTH OF THE IA/MO BORDER REGION MAKING IT INTO WEST CENTRAL
IL BY EARLY AFTERNOON AND OPEN UP AS THE AFTERNOON PROGRESSES.
THE SFC LOW PROGGED BY MOST 00Z RUN SOLUTIONS TO JOG A BIT
FURTHER SOUTH/SOUTHEAST OF THE UPPER LOW TOWARD THE STL AREA AND
INTO SOUTHERN IL. THE CURRENT WEST-TO-EAST ORIENTED WING OF
SHOWERS AND A FEW STORMS WILL LOOK TO WEAKEN AS IT PUSHES NORTH
AND NORTHEAST. SECONDARY WING NOW DEVELOPING ACRS NORTHERN
MO...WILL TAKE OVER AND PUSH ACRS THE CWA THROUGH THE EARLY
MORNING PERIOD. THIS BAND FORMING ON CONVERGENT H85 MB 30-40+ KT
SOUTHWESTERLY LLJ WILL BE THE MAIN PRECIP SHOW THIS
MORNING...BEFORE OCCLUDED FLOW TAKES OVER AND BETTER CONVERGENCE
SHIFTS TO THE SOUTHEAST OF THE LOCAL FCST AREA THIS AFTERNOON.
THUS MORE EMBEDDED THUNDER EARLY THROUGH MID MORNING...BEFORE
ACTIVITY SWITCHES TO MORE WRAP AROUND SHOWERS OR RAIN THIS
AFTERNOON ACRS THE SOUTHERN 2/3S OF THE AREA...EVENTUALLY
DECREASING BY LATE AFTERNOON AND INTO THE EVENING WITH DEEPENING
EAST-NORTHEAST FLOW.

BETTER CONVERGENT AXIS FOR A SWATH OF HEAVIER RAIN WITH AN
ADDITIONAL HALF INCH UP TO AN INCH POSSIBLE LOOKING TO TAKE SHAPE
ALONG THE I80 CORRIDOR...AND A FEW COUNTIES SOUTHWARD TOWARD THE
FAIRFIELD...BRL...SOUTH GALESBURG AREAS. OTHER AREAS NORTH AND
SOUTH OF THIS SWATH TO GET A QUARTER INCH OR LESS. AS LONG AS THE
DRY PUNCH TRIES TO NOSE INTO THE AREA...A FEW STRONGER STORM CELLS
WITH LOCALLY HEAVY DOWNPOURS AND SMALL HAIL POSSIBLE THIS
MORNING...MAINLY AREAS SOUTH OF I80. ANOTHER DAY OF TEMP CONTRAST
FROM NORTH TO SOUTH...HIGHS MAY NOT GET OUT OF THE 40S IN THE
NORTHEAST...WHILE THE FAR SOUTH MAY MAKE THE UPPER 50S.

TONIGHT...SOME LINGERING PATCHES OF WRAP AROUND OCCLUSION LIGHT
RAIN IN THE SOUTHERN THIRD TO HALF OF THE CWA THROUGH MID
EVENING...BEFORE DRYING/DEEPENING NORTHEAST FLOW ACCELERATES THE
CLEAR OUT FROM THAT DIRECTION IN THE OVERNIGHT. COOL IN-FLUX MAY
MAKE FOR WIDESPREAD LOWS IN THE LOW TO MID 30S NORTH OF I80...BUT
EXPECT ENOUGH NORTHEAST SFC WINDS OF 5-10 MPH TO MIX AND PREVENT
MUCH FROST FORMATION. WILL LET THE DAYSHIFT FURTHER ASSESS
COOL/FROST POTENTIAL FOR EARLY SUNDAY MORNING.


.LONG TERM...(SUNDAY THROUGH NEXT FRIDAY)
ISSUED AT 313 AM CDT SAT APR 25 2015

OVERVIEW...SUNDAY THROUGH MIDWEEK LOOKS DRY WITH NEAR TO BELOW
NORMAL TEMPERATURES. A WARMING TREND IS SUGGESTED BY LATE NEXT WEEK
AS AN UPPER LEVEL RIDGE BUILDS OVER THE WESTERN AND CENTRAL U.S.

SUNDAY THROUGH TUESDAY...HIGH PRESSURE AT THE SURFACE AND AN UPPER
LEVEL RIDGE EMBEDDED IN A SPLIT FLOW REGIME ALOFT...WILL PROVIDE DRY
WEATHER. LOW LEVEL E-NE WINDS WILL CHANNEL VERY DRY AIR AT THE LOW
LEVELS OUT OF THE GREAT LAKES EARLY IN THE PERIOD BEFORE BECOMING
LIGHT WITH THE CENTER OF THE BROAD RIDGE PASSING OVERHEAD BY TUE
NIGHT. THE DRY AIR WILL FAVOR MOSTLY CLEAR SKIES AND LARGER THAN
NORMAL DIURNAL SWINGS...ALLOWING HIGHS TO REACH AT LEAST THE LOWER
60S SUNDAY INTO MONDAY...MODERATING TO MID AND UPPER 60S TUESDAY.
GUIDANCE LOWS IN THE 30S MAY BE A BIT TOO OPTIMISTIC...ESPECIALLY
FOR MONDAY NIGHT WHEN WINDS WILL BE LIGHTEST. WILL THUS HAVE A
THREAT OF FROST OR POSSIBLY FREEZING TEMPERATURES TO MONITOR IN
LATER FORECASTS FOR BOTH NIGHTS.

WEDNESDAY THROUGH FRIDAY...MODELS CONTINUE TO ADVERTISE PHASING OF
WEAK NORTHERN AND SOUTHERN STREAM SYSTEMS OVER THE CENTRAL U.S.
EARLY WED...WITH ONLY A WEAK COLD FRONT OR TROUGH IN THE DIFFUSE
SURFACE PRESSURE FIELDS. THIS IS FOLLOWED BY A DEVELOPING TROUGH TO
THE EAST AND RIDGE OUT WEST...WHICH MIGRATES EASTWARD AND SPREADS
WARMER AIR AT 850 MB INTO THE FORECAST AREA. THIS SHOULD MODERATE
HIGHS BACK INTO THE 70S BY FRIDAY. WITH GULF MOISTURE CUT OFF AND
LITTLE FORCING...DRY IS THE WAY TO GO FOR WED INTO THU. GFS AND
ECMWF THEN DEPICT GULF MOISTURE RETURN AS EARLY AS FRIDAY...BUT AT
THE SAME TIME HAVE NO SIGNIFICANT BOUNDARIES OR FORCING ALOFT TO
JUSTIFY OTHER THAN CONTINUED DRY FORECAST.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1142 PM CDT FRI APR 24 2015

CLOUDY SKIES WITH LOWER VFR CONDITIONS WILL DETERIORATE TO MVFR
CONDITIONS BY 25/08Z WITH INTERVALS OF IFR CONDITIONS POSSIBLE
AFTER 25/10Z AS AREAS OF RAIN DEVELOP THAT WILL LAST INTO THE
LATE MORNING HOURS. ISOLATED THUNDER MAY APPROACH THE BRL TERMINAL
AND TO A LESSER EXTENT THE MLI TERMINAL TOWARD DAYBREAK. THIS IS
HANDLED AS A VCTS AT THE BRL TERMINAL. EAST WINDS OF 10 TO 15+ KTS
WILL SHIFT TO THE NORTHEAST AND NORTH BY MID DAY AND INCREASE TO
12 TO 20+ KTS AS THE SURFACE LOW PASSES SOUTH. THE RAINS WILL END
IN THE EARLY AFTERNOON WITH MVFR CONDITIONS LASTING UNTIL 26/00Z
AT LATEST WITH CLEARING SKIES FROM THE NORTH.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...SHEETS
AVIATION...NICHOLS



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