Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 241801
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
101 PM CDT TUE MAR 24 2015

.UPDATE...
ISSUED AT 1242 PM CDT TUE MAR 24 2015

EARLIER UPDATE TO SLOW ADVANCING RAIN AND REMOVE MOST OF THUNDER
FOR THE AFTERNOON WITH RIDGE AND DRY AIR/EAST-SOUTHEAST FETCH
HAVING AN AFFECT. COOLED HIGH TEMPS SOME CLOSER TO UPPER 30S TO
LOW 40S...ALTHOUGH SOME THINNING IN THE LOW CLOUD DECK TODAY HAS HELPED
TO ALLOW FOR SOME WARMING. BUT EAST-SOUTHEAST FETCH OFF NORTHERN
IL SNOW FIELDS MAY KEEP THE FAR NORTHEASTERN CWA IN THE MID 30S
DESPITE HAVING THE LONGEST DURATION OF AT LEAST FILTERED
ISOLATION. WILL BE LOOKING AT IT THROUGH THE AFTERNOON PACKAGE
RELEASE...BUT SOME CONCERN THAT WHEN THE RAIN FINALLY HITS THE HWY
20 CORRIDOR FROM JUST WEST OF DBQ...EASTWARD TO FREEPORT IL THAT
IT MAY BE MORE OF A FREEZING RAIN POTENTIAL FOR AT LEAST A FEW
HOURS BEFORE TEMPS/WBZS CAN RE-STABILIZE BACK AROUND 32 TO 33
DEGREES OR SO. AFTER WEAKENING WING OF MAINLY LIGHT RAIN LIFTS UP
THROUGH THE CWA THIS AFTERNOON AND THE NORTHEAST HALF OF THE FCST
AREA STAYS MAINLY DRY...THE MAIN PRECIP SHOW STILL APPEARS TO BE
TONIGHT AS MAIN UPPER TROF SWINGS ACRS OVERHEAD AND SFC LOW ROLLS
OUT PF THE SOUTHERN PLAINS TO WESTERN IL BY 12 AM TO 2 AM OR SO. ..12..

&&

.SYNOPSIS...
ISSUED AT 338 AM CDT TUE MAR 24 2015

SCATTERED THUNDERSTORMS WERE OVER THE PLAINS INTO NW MO EARLY THIS
MORNING IN THE ELEVATED WARM ADVECTION AND LOW LEVEL JET
CONVERGENCE AHEAD OF A STRONG SHORTWAVE MOVING OUT OF THE ROCKIES.
A MID LEVEL RIDGE OUT AHEAD PASSING THROUGH IA...ALONG WITH DRIER
E-SE LOW LEVEL FLOW OUT OF SURFACE HIGH PRESSURE OVER THE GREAT
LAKES WAS SUPPRESSING THE CONVECTION TO MAINLY SOUTH OF THE
FORECAST AREA...OUTSIDE A BAND OF LIGHT SHOWERS FALLING AS
FREEZING RAIN OVER FAR NE MO INTO THE KEOK AREA AT 3 AM. A
CONTINUED LOW LEVEL EASTERLY FLOW WAS RESULTING IN WIDESPREAD
SUBFREEZING TEMPERATURES ACROSS THE FORECAST AREA...FROM THE MID
20S NORTHEAST TO AROUND 32 IN THE FAR SOUTH AND SE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT TUE MAR 24 2015

THE ADVANCING SHORTWAVE WILL BOOST A DEVELOPING SURFACE LOW OVER THE
OK PANHANDLE NORTHEASTWARD...WITH NEAR MODEL CONSENSUS IN THE 00Z
RUN TRACKING THIS FEATURE THROUGH CENTRAL OR NW IL TONIGHT...INTO
LOWER MI BY WED. THIS WILL SEND WIDESPREAD RAIN THROUGH THE
FORECAST AREA...WITH PRECIPITATION TYPE ISSUES IN THE FAR SOUTH
EARLY THIS MORNING AND THEN IN THE NORTHWEST OVERNIGHT.

IN THE NEAR TERM...THE WEAK MID LEVEL SUBSIDENCE OVER THE AREA WILL
DECREASE BY MID MORNING WHILE MASS CONVERGENCE ON THE NOSE OF A
NEARLY 40 KT WARM...MOIST ADVECTION FLOW AT 850 MB WILL BE FAVORABLE
FOR SHOWERS TO SPREAD INTO THE SOUTHERN HALF OF THE FORECAST AREA BY
MIDDAY. EARLY THIS MORNING...TEMPERATURES HOVERING NEAR TO BELOW
FREEZING MAY RESULT IN SOME FREEZING RAIN AS THE SHOWERS BEGIN TO
ADVANCE NORTHEAST AND BECOME MORE WIDESPREAD ACROSS NE MO INTO
FAR SE IA AND W CENTRAL IL. WITH WARM SURFACE CONDITIONS AND
TEMPERATURES EXPECTED TO NUDGE ABOVE THE FREEZING MARK IN THIS
AREA AFTER SUNRISE...ICE ACCUMULATION DOES NOT APPEAR TO BE A
SIGNIFICANT ISSUE...BUT WILL NEED TO MENTION FREEZING RAIN.

TODAY...THE BEST POTENTIAL FOR SHOWERS WILL BE IN THE MORNING ACROSS
THE SOUTH AND THEN OVER THE ENTIRE AREA IN THE AFTERNOON...
ESPECIALLY LATE AS THE NEGATIVE TILT MID LEVEL SHORTWAVE ADVANCES
TOWARD THE AREA. HAVE ADJUSTED POPS ALONG THESE LINES. WHILE LOW
CLOUDS MAY BREAK UP IN THE EAST...HIGHER CLOUDS WILL PROVIDE MOSTLY
CLOUDY CONDITIONS WHERE IT IS NOT RAINING...WHICH COMBINED WITH THE
COOL...DRY EASTERLY FLOW...WILL HOLD TEMPERATURES DOWN TODAY AND
HAVE GONE OPTIMISTICALLY WITH HIGHS FROM AROUND 40 NORTH TO THE
MID 40S SOUTH. STEEP MID LEVEL LAPSE RATES AND SUFFICIENT
CONVERGENCE AT 850 MB MAY LEAD TO ISOLATED THUNDERSTORMS MENTION
IN THE SOUTH THIS MORNING AND THEN OVER MUCH OF THE AREA BY LATE
AFTERNOON.

TONIGHT...STRONG MID LEVEL FORCING LIFTS THROUGH THE AREA FOR
WIDESPREAD RAIN WITH A CONTINUED POTENTIAL FOR AT LEAST ISOLATED
THUNDERSTORMS IN THE EVENING. QPF AMOUNTS AROUND A HALF TO POSSIBLY
NEAR 1 INCH ARE LIKELY FROM THIS SYSTEM WITH THE HEAVIEST AMOUNTS IN
THE EVENING PERIOD. FORECAST SOUNDINGS IN THE NORTHWEST...OR AROUND
INDEPENDENCE SUGGEST A POTENTIAL FOR MIXED PRECIPITATION...WHICH
FOR NOW WILL BE INCLUDED AS A MENTION OF A RAIN/SNOW MIX WITH
POSSIBLE TRACE ACCUMULATIONS THIS EVENING. THIS IS LOW CONFIDENCE
AND WILL HAVE TO BE WATCHED CAREFULLY AS ANY NUDGE IN CRITICAL
THERMAL FIELDS COULD RESULT IN AT LEAST LIGHT ACCUMULATIONS.
CURRENT TIMING HAS THE UPPER WAVE AND PRECIPITATION EXITING TO THE
NORTHEAST BETWEEN MIDNIGHT AND 6 AM AND HAVE TRENDED THE FORECAST
LIKEWISE.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 338 AM CDT TUE MAR 24 2015

FORECAST FOCUS ON COLDER WEATHER REMAINDER OF THE WEEK THEN A
WARM-UP LATE THIS WEEKEND. LITTLE OR NO PRECIPITATION EXPECTED
THROUGH THIS PERIOD.

WEDNESDAY AND WEDNESDAY NIGHT...STORM SYSTEM WILL BE LIFTING
INTO THE GREAT LAKES REGION ON WEDNESDAY WITH A WEST WIND KEEPING
TEMPERATURES SEASONAL. MAXIMUM TEMPERATURES WILL RANGE FROM THE
UPPER 40S ALONG HIGHWAY 20 TO THE LOWER 60S IN EXTREME NORTHEAST MO.
A STRONG COLD FRONT WILL BE ARRIVING LATER IN THE DAY AND THERE IS A
CHANCE OF LIGHT PRECIPITATION IN OUR FAR SOUTH WEDNESDAY EVENING.
HOWEVER...THE BULK OF THE PRECIPITATION WILL BE SOUTH OF THE CWA AS
A STORM SYSTEM TRACKS ACROSS THE MID MS VALLEY INTO THE OH VALLEY.

THURSDAY THROUGH SATURDAY...WITH THE PASSAGE OF THE FRONT COLDER
WEATHER WILL RETURN FOR THURSDAY AND FRIDAY. HIGHS WILL BE IN THE
40S ON THURSDAY BUT MAINLY IN THE 30S ON FRIDAY...AND THEN BACK IN
THE 40S ON SATURDAY. MINIMUM TEMPERATURES LOOK TO BE IN THE 20S. IN
THIS NORTHWEST FLOW OPERATIONAL MODELS INDICATE A SERIES OF SHORT
WAVES DIVING SOUTHEAST BUT MISSING THE DVN CWA EITHER TO OUR WEST OR
EAST.  THE AIRMASS WOULD CERTAINLY BE COLD ENOUGH TO SUPPORT SNOW
WITH THESE DISTURBANCES BUT CONFIDENCE IS LOW IN THE TIMING/PLACEMENT
OF THESE INDIVIDUAL WAVES IN THE FLOW...AND THE CURRENT DRY FORECAST
COULD CHANGE.

SUNDAY THROUGH MONDAY...MILDER TEMPERATURES WITH A RETURN TO A ZONAL
FLOW. MAXIMUM TEMPERATURES SHOULD PUSH INTO THE 50S TO LOWER 60S.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1242 PM CDT TUE MAR 24 2015

DRY AIR AND LINGERING RIDGE AXIS HAVING IT/S AFFECT MAKING FOR
TEMPORARY BOUTS OF VFR CIGS THIS AFTERNOON. BUT AS THE MAIN LOW
PRESSURE SYSTEM AND TROF ALOFT PUSH OUT OF THE SOUTHERN PLAINS
TOWARD THE REGION....CIGS WILL LOWER AND PRECIP WILL HAVE A BETTER
TIME MAKING IT ACRS THE AREA. JUST SOME PASSING BOUTS OF MAINLY
LIGHT RAIN/MVFR CONDITIONS AT BRL AND CID THIS AFTERNOON. CIGS AND
SOME VSBYS TO LOWER TO LOW MVFR AND INTO IFR CATEGORY THIS EVENING
AND OVERNIGHT. AS THE RAIN LETS UP BUT LOW CLOUDS LINGER...MOST
TERMINALS SUBJECT TO IFR TO LIFR CONDITIONS FROM MIDNIGHT THROUGH
WED MORNING BEFORE CIGS START TO LIFT AGAIN AND SFC WINDS SWING TO
THE WEST AND INCREASE. SOME HIGH BASED THUNDERSTORMS EMBEDDED
IN THE AREAS OF RAIN POSSIBLE IN THE VCNTY OF BRL THIS EVENING...AND
EVEN MLI BY MID EVENING THROUGH 11 PM CDT OR SO.    ..12..

&&

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

$$

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






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