Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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311
FXUS63 KDVN 102321
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
521 PM CST WED FEB 10 2016

...AVIATION UPDATE...

.SYNOPSIS...
ISSUED AT 341 PM CST WED FEB 10 2016

18Z SFC DATA HAS A WEAK LOW NEAR KOFK IN NORTHEAST NEBRASKA WITH A
WARM FRONT INTO EASTERN KANSAS. DEW POINTS WERE IN THE SINGLE DIGITS
ABOVE AND BELOW ZERO FROM THE UPPER MIDWEST INTO THE GREAT LAKES.
DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 341 PM CST WED FEB 10 2016

RADAR TRENDS THE PAST FEW HOURS SHOW THE SNOW BREAKING UP ACROSS
CENTRAL IOWA. THE BETTER FORCING HAS MOVING INTO SOUTHEAST IOWA AND
SOUTHWEST ILLINOIS AND HAS GENERATED SEVERAL NARROW BANDS OF
RELATIVELY HEAVIER SNOW WITHIN A LARGER BAND OF LIGHT SNOW.

EXTRAPOLATION OF THE CURRENT SNOW BANDS AND APPLYING A ROUGH DECAY
RATE INDICATES LIGHT ACCUMULATING SNOW WILL CONTINUE INTO THE LATE
AFTERNOON ACROSS THE SOUTHWEST THIRD OF THE AREA. RADAR RETURNS
SUGGEST A DUSTING TO UNDER AN INCH OF ACCUMULATION. HOWEVER...
LOCALIZED AMOUNTS OVER AN INCH ARE LIKELY WHERE THE HEAVIER SNOW
BANDS SET UP.

TONIGHT...ANY LINGERING LIGHT SNOW/FLURRIES WILL END BY MID EVENING
WITH LITTLE IF ANY ADDITIONAL ACCUMULATION. FROM MID EVENING THROUGH
SUNRISE THURSDAY DRY CONDITIONS ARE EXPECTED AS HIGH PRESSURE BUILDS
INTO THE MIDWEST.

QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA ON THURSDAY AS
HIGH PRESSURE MOVES THROUGH THE MIDWEST. TEMPERATURES WILL AVERAGE
BELOW NORMAL.     ..08..

.LONG TERM...(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 341 PM CST WED FEB 10 2016

THURSDAY NIGHT AND FRIDAY...ONGOING BROAD NORTHWESTERLIES BETWEEN
HUDSON BAY UPPER LOW...AND WESTERN CONUS RIDGING TO KEEP ACTIVE
CLIPPER TRACK SHUTTLING SOUTHEASTWARD DOWN ACRS THE REGION. LATEST
12Z RUN SOLUTIONS VARY ON STRENGTH AND MOISTURE AVAILABILITY WITH
THE NEXT WAVE RIPPLING DOWN THU NIGHT INTO EARLY FRI MORNING...
RANGING FROM THE ECMWF WHICH BARELY PRODUCES A TENTH OF AN INCH IN
THE FAR SOUTHWESTERN CORNER OF THE DVN CWA/MEMPHIS MO...TO THE GEM
WHICH HAS A WIDESPREAD HALF INCH TO AN INCH SOUTHWEST OF A CEDAR
RAPIDS TO QUAD CITY AREA LINE BY 12Z FRI. FOR NOW WILL GO WITH A
SREF BLEND THE SUGGESTS LIGHT SNOW ACRS MUCH OF THE SOUTHWESTERN
HALF OF THE CWA...BUT AMOUNTS GENERALLY LESS THAN A HALF INCH WITH A
DRY AIRMASS TO OVERCOME AS THE CLIPPER ARRIVES AFTER MID EVENING.
WITH CLOUDS AND PRE-SYSTEM SOUTHWESTERLY LLVL FLOW...TEMPS MAY HOLD
STEADY OR EVEN RISE SOME OVERNIGHT.

THE SNOW OR WHATEVER SNOW MAKES IT ACRS THE CWA...WILL EXIT QUICKLY
OUT OF THE AREA FRI MORNING...THEN SIGNS ARE THAT A RE-ENFORCING
1045 MB ARCTIC HIGH TO DUMP OUT OF CANADA AND DOWN ACRS THE UPPER
MIDWEST. THIS FEATURE BESIDES ANOTHER ROUND OF ROBUST CAA...WILL
SCOUR THINGS OUT INTO FRI NIGHT. LOWS BY SAT MORNING TO BE COLD...
WITH LOW SINGLE DIGITS SOUTH OF I80...TO 5 TO 8 BELOW ALONG AND
NORTHWEST OF CID-DBQ LINE. DESPITE DECREASING WINDS LATE...THEY
STILL MAY MAINTAIN CLOSE TO 10 MPH AND INDUCE WIND CHILLS NEAR
ADVISORY LEVEL ALONG AND NORTH OF THE HWY 30 CORRIDOR LATE FRI NIGHT
THROUGH MID SAT MORNING.

SATURDAY AND SUNDAY...COLD CORE RIDGE SLIDES ACRS THE REGION ON SAT
WITH HIGH TEMP RECOVERY FROM THE UPPER SINGLE DIGITS TO MID TEENS.
THEN HIGH CLOUDS WILL BE ON THE INCREASE FROM THE NORTHWEST SAT
AFTERNOON AND EVENING...AS ANOTHER WAVE FROM THE NORTHEASTERN
PACIFIC RIDES A DAMPENING UPPER RIDGE ACRS THE ROCKIES AND ROLLS
ACRS THE MID TO UPPER MS RIVER VALLEY LATER ON SUNDAY. LEAD VORT
AND ASSOCIATED WARM AIR ADVECTION/WAA/ WING MAY TRY TO GET IN THE
SOUTHWESTERN CWA AS EARLY AS SAT EVENING...BUT INITIALLY DRY UP
SOME AS IT ENCOUNTERS BACK OF DEPARTING DRY RIDGE. SECONDARY WAA
WING AHEAD OF THE MAIN WAVE WILL THEN LOOK TO MAKE IT ACRS THE
WESTERN HALF WEST OF MS RIVER/OR SOUTHWESTERN HALF OF THE FCST
AREA LATE SAT NIGHT INTO SUNDAY MORNING...WITH THE GFS KICKING OUT
1-2 INCHES BY SUNDAY MORNING AND THE ECMWF UP TO AN INCH. A DRY
FLUFFY SNOW WITH HIGH LSR/S OF AT LEAST 16:1. THE 12Z ECMWF THEN
CONTINUES THE MAIN CLIPPER EASTWARD ACRS THE REST OF THE AREA WITH
ANOTHER HALF INCH... UP TO 1.5 INCHES BY LATE AFTERNOON ACRS MUCH
OF THE CWA BEFORE TAPERING TO FLURRIES. THE 12Z GFS IS MUCH MORE
BULLISH...MORE PHASED AND WET WITH AN ADDITIONAL 2-4 INCHES BY 00Z
MON AND THE HIGHER AMOUNTS SOUTH OF I80. THE 12Z GEM SUPPORTS MORE
THE EURO AND FOR NOW/ITS STILL EARLY/ WILL LEAN THAT WAY WITH THE
IDEA OF MOST AREAS GETTING 1-3 INCHES OF SNOW OVER A DURATION FROM
SAT NIGHT THROUGH SUNDAY EVENING.

MONDAY THROUGH NEXT WEDNESDAY...12Z MEDIUM RANGE MODELS AND ENSEMBLES
SUGGEST SOME TYPE OF L/W TROF PHASING OCCURRING OVER OR JUST EAST OF
THE AREA MON INTO TUE...WITH RESULTANT MORE SIGNIFICANT STORM
DEVELOPING TO THE SOUTHEAST OF THE LOCAL AREA OF CONCERN. BEHIND THAT
SYSTEM OR WHAT EVER TROF CAN DEVELOP AND BUILD EAST...LONGER RANGE
INDICATIONS SUGGEST CLIPPER PATTERN TO RELOAD BUT AT A FLATTER
REGIME...POSSIBLY ALLOWING FOR BUILDING UPSTREAM MILDER AIR MASS AND
RIDGING TO EDGE EAST ACRS THE AREA TOWARD MID NEXT WEEK. CLIPPER AND
ASSOCIATED PRECIP MAY GET SHUNTED MORE TO THE NORTHWEST/ NORTH OF THE
AREA AGAIN WITH OCCASIONAL WARM DRAWS PULLED UP ACRS THE LOCAL AREA
BY THESE SYSTEMS TUE INTO WED.     ..12..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 521 PM CST WED FEB 10 2016

A WEAK UPPER LEVEL DISTURBANCE PRODUCING LIGHT SNOW OR FLURRIES IN
SOUTHEAST IOWA AND NORTHERN MO WILL STREAM OUT OF THE REGION THIS
EVENING...LEAVING ONLY MID AND HIGH LEVEL CLOUDS...LIGHT WINDS
AND VFR CONDITIONS. ANOTHER SIMILAR WEAK SYSTEM WILL ARRIVE
THURSDAY NIGHT...JUST BEYOND THE CURRENT FORECAST PERIOD. THUS
VFR CONDITIONS WILL CONTINUE WITH HIGH PRESSURE BUILDING INTO IOWA
PROVIDING LIGHT WINDS THAT WILL EVENTUALLY BACK FROM NORTH TONIGHT
TO SOUTHWEST BY THURSDAY AFTERNOON.

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...SHEETS



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