Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 271605
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1005 AM CST TUE JAN 27 2015

.UPDATE...
ISSUED AT 1000 AM CST TUE JAN 27 2015

HAVE UPDATED THE GRIDS TO GO MORE PESSIMISTIC ON CLOUD COVER AND
TO LOWER TEMPERATURES A COUPLE OF DEGREES. STRONG INVERSION AT 850
MB WITH LOW LEVEL MOISTURE TRAPPED BELOW...ALONG WITH A NORTHEAST
WIND AND SNOW COVER SHOULD KEEP LOW STRATUS LOCKED IN MUCH OF THE
DAY. THE EXCEPTION IS OUR FAR SW WHERE THAT AREA SHOULD HAVE MORE
SUNSHINE. VISIBLE SATELLITE SHOWS EXTENSIVE STRATUS COVERING MUCH
OF THE DVN CWA AND NORTHWARD INTO MN AND WI. THESE CLOUDS ARE
SPREADING SOUTHWARD IN THE CYCLONIC FLOW ASSOCIATED WITH THE DEEP
TROUGH IN THE EAST. HAVE LINGERED THE CLOUDS INTO THIS EVENING BUT
UNFORTUNATELY CONFIDENCE IS LOW WITH THE CLOUD TRENDS.

&&

.SYNOPSIS...
ISSUED AT 334 AM CST TUE JAN 27 2015

THE POWERFUL NOREASTER CONTINUES TO SPIN OFF THE COAST OF
MASSACHUSETTS THIS MORNING...AND THIS IS HAVING AN IMPACT ON OUR
WEATHER. STRATUS...LOTS AND LOTS OF STATUS EXTENDS WEST FROM THAT
INTENSE STORM...ALL THE WAY CONTINUOUSLY THROUGH A LINE FROM
WATERLOO THROUGH BURLINGTON IOWA. THUS...IT HAS BEEN CLOUDY ALL
NIGHT EAST OF THAT LINE...AND CLEAR TO THE WEST. AN INVERTED TROF
EXTENDS FROM WESTERN INDIANA THROUGH NORTH CENTRAL ILLINOIS...AND
THIS IS KEEPING THE COLD SATURATED AIR CONFINED TO OUR NORTHEAST
CWA...WHILE THE NORTHWEST WINDS OVER THE WESTERN 1/2 ARE HELPING
EVEN OUR CLEAR SKY LOCATIONS HOLD IN THE MID TO UPPER 30S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST TUE JAN 27 2015

CLOUDS AND TEMPERATURES ARE TODAYS CHALLENGE. I WILL STAY THE
COURSE ON KEEPING CLOUDY LOCATIONS CLOUDY ALL DAY TODAY AND WELL
INTO TONIGHT...AND ALSO INTRODUCE SOME CLOUDY HOURS FOR WESTERN
LOCATIONS TODAY...AS THE FLOW ALOFT TURNS NORTH NORTHEAST AND
ADVECTS THE STRATUS IN...A TREND ALREADY BEGINNING ON SATELLITE
EARLY TODAY. WITH SNOW COVER...STRATUS...AND LIGHT NORTHEAST WINDS
OVER OUR NORTHEAST COUNTIES...I FEEL WE WILL NOT SEE A SIGNIFICANT
WARM UP TODAY...AND HAVE HELD TEMPERATURES TO THE LOWER 30S FOR
HIGHS. TO THE WEST...WE WILL ALSO NOT SEE A SIGNIFICANT WARM
UP...BUT SINCE WE ARE STARTING OUT SO MILD...UPPER 30S TO LOWER 40S
SHOULD BE EASILY REACHED THROUGH INCREASED MIXING LATER TODAY. IF IT
IS SUNNY FOR MORE THAN A FEW MINUTES DURING ANY PART OF THE MID DAY
HOURS...THE SOUTHWEST MAY ONCE AGAIN MAKE A RUN AT 50 LIKE
YESTERDAY.

TONIGHT...CLOUDS MAY EVENTUALLY THIN OUT...AND LOWS IN THE UPPER
TEENS EAST TO UPPER 20S WEST ARE EXPECTED. NORTH TO NORTHEAST WINDS
WILL DECREASE TO UNDER 5 MPH THIS EVENING...THEN SWITCH TO SOUTHEAST
AROUND 10 MPH BY MORNING. THUS FOG SHOULD NOT BECOME A WIDESPREAD
THREAT...AND WILL BE LEAVING THIS OUT OF THE FORECAST FOR NOW.
ERVIN

.LONG TERM...(WEDNESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 AM CST TUE JAN 27 2015

WEDNESDAY THROUGH FRIDAY...IMPRESSIVE THERMAL DRAW OUT AHEAD OF
APPROACHING WAVE FOR WED...SUBSTANTIAL WARM BULGE ALOFT AND TEMP
CHALLENGE WILL BE HOW DEEP WE MIX INTO THE BASE OF THAT BROAD
INVERSION. MOST TEMP GUIDANCE HAS BACKED OFF FROM PREVIOUS DAYS WITH
COOLER HIGHS AND SHALLOW MIXING...BUT ERODED SNOW COVER AND DEEPER
SOUTHEASTERLY MIXING EVEN UP TO JUST H950 MB SUPPORTS HIGHS FROM THE
UPPER 30S/AROUND 40 IN THE NORTH...TO THE LOW TO MID 50S IN THE FAR
SOUTHWEST AND THAT IS WHAT WILL BE ADVERTISED. DEEPER MIXING UP INTO
INVERSION BASE EVEN TO JUST TO H925 MB SUPPORTS MORE MID 40S INTO
THE MID 50S OVER THE SNOWCOVER-LESS AREAS. BOTH THE 00Z GFS AND THE
ECMWF ROLL THE SFC LOW ACRS THE CENTRAL INTO THE NORTHERN CWA WED
NIGHT AS THE UPPER TROF DIGS ACRS THE MS RVR VALLEY. THIS SCENARIO
SUGGESTS MORE PHASING/STRENGTHENING TO TAKE PLACE EAST OF THE CWA
ACRS THE WESTERN GRT LKS AND DOWN ACRS THE OH RVR VALLEY ON THU.
LIMITED LLVL MOISTURE RETURN-DEPTH UNDER THE INVERSION DRY WEDGE/
WHICH WILL TAKE SOME TIME TO TRY AND TOP-DOWN SATURATE INTO THU
MORNING/ MAY LIMIT THE PRECIP THAT BREAKS OUT AS MAINLY DRIZZLE. A
BIT DEEPER SATURATION MAY ALLOW FOR SOME PATCHY LIGHT RAIN WED
NIGHT INTO EARLY THU AM. AFTER A MILD DAY...CONTINUED LLVL WARMING
AND SFC DPT INCREASE INTO WED NIGHT SUGGESTS LITTLE IF ANY CHANCE
FRO FREEZING DRIZZLE OR RAIN. IF ANYTHING...SOME TOP DOWN COOLING
AND MID LEVEL SEEDER FEEDERS LATE WED NIGHT/THU MORNING MAY ALLOW
FOR A RAIN/SNOW MIX TRYING TO CREEP IN BEHIND THE EXITING LOW
ESPECIALLY IN THE NORTHWESTERN CWA. WILL NOT ADD IT NOW...BUT WITH
CONVERGENT SFC FLOW AROUND THE LOW AND INCREASING SFC DPTS...THERE
MAY BE PERIODS OF DENSE FOG DEVELOPMENT WED EVENING AND INTO THE
OVERNIGHT BEFORE THE BRISK NORTHWESTERLY BL FLOW REALLY SURGES IN
FROM THE WEST TOWARD SUNRISE THU. BRISK NORTHWEST WINDS OF 20-30
MPH AND GUSTS TO NEAR 40...WITH SCTRD LIGHT SNOW SHOWERS OR
FLURRIES THU MORNING THRU MIDDAY IN WAKE OF STRENGTHENING LOW
PULSING OFF TO THE EAST THRU THE GRT LKS. THU HIGHS IN THE
MORNING. SFC RIDGE ENGULFING THE REGION THU NIGHT AND SFC WIND
DROP-OFF WILL MAKE FOR COOLING TEMPS IN THE MID TEENS TO LOWER
20S...WOULD BE COLDER IF WE WERE ABLE TO GET MORE WIDESPREAD SNOW
COVER AGAIN BUT THAT NEW SNOW POTENTIAL APPEARS LOW ATTM. DESPITE
SUNSHINE UNDER PASSING ANTICYCLONE...FRESHLY ARRIVED COOL AIRMASS
WILL ONLY WARM INTO THE MID 20S IN THE FAR NORTH...TO THE LOW TO
MID 30S IN THE SOUTH FOR FRI. COOL FRI EVENING BEFORE LIGHT
SOUTHEAST RETURN FLOW HALTS TEMP BOTTOM OUT LATE FRI NIGHT.

SATURDAY THROUGH NEXT MONDAY...BOTH THE 00Z RUN GFS AND ECMWF SUGGEST
ENOUGH PHASING OF THE NEXT ROUND OF INCOMING UPSTREAM WAVE ENERGY
TO PRODUCE A DECENT PRECIP EVENT FROM SAT AFTERNOON THOUGH AT
LEAST SUNDAY MORNING. WITH COLD AIR IN PLACE AND SOME SIGNS OF
PRE- SYSTEM MOISTURE DRAW OFF THE WESTERN GULF...THE MEDIUM RANGE
SOLUTIONS ARE SUGGESTING A LONG DURATION SNOW EVENT WITH SEVERAL
INCHES OF ACCUMULATION POSSIBLE BY SUNDAY AFTERNOON. WILL CONTINUE
TO TREND POPS UP AND WILL HAVE TO WATCH PHASING TRENDS IN THE
MODEL RUNS OVER THE NEXT SEVERAL DAYS. AFTER WHAT EVER CAN OCCUR
OVER THE WEEKEND/EXITING L/W TROF...THE THREAT FOR AN ARCTIC AIR
MASS INVASION DOWN ACRS THE REGION STILL LOOMS FROM SUNDAY NIGHT
INTO EARLY NEXT WEEK. WITH FRESH SNOW COVER THE TEMPS THAT WILL BE
ADVERTISED FOR BOTH LOWS AND HIGHS SUNDAY NIGHT THRU AT LEAST TUE
AM MAY STILL BE TOO OPTIMISTICALLY WARM.    ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1000 AM CST TUE JAN 27 2015

MVFR CIGS TODAY THEN BECOMING VFR TONIGHT AND ALSO ON WEDNESDAY.
NORTHEAST WINDS AROUND 10 KNOTS OR LESS TODAY THEN BECOMING
SOUTHEAST TONIGHT AND CONTINUING ON WEDNESDAY. WIND SPEEDS WILL
INCREASE ON WEDNESDAY TO 10 TO 20 KNOTS.

&&

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

$$

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








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