FXUS63 KDVN 290928
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
328 AM CST SUN NOV 29 2009

.SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING MAIN FRONTAL BOUNDARY ALMOST
BISECTING THE DVN CWA FROM NE-TO-SW AS WELL AS A WEAK WAVE UPON IT
JUST SOUTHWEST OF THE QCA. A POST-FRONTAL LOW STRATUS DECK WAS NOTED
ACRS SOUTHWEST AND CENTRAL IA...AND SOME ECHOES WHERE LIGHTING UP
THE 88D ACRS CENTRAL INTO NORTHEASTERN IA IN TEMPORARY ELEVATED WAA
REGIME AND FRONTOGENETICAL FORCING BAND. MOST OF THE PRECIP WAS
REMAINING ALOFT WITH THE STILL DRY LOWER LEVELS. ALOFT...A NORTHERN
STREAM WAVE WAS SEEN ON W/V IMAGERY DIGGING DOWN ACRS THE NORTHERN
PLAINS ATTM WITH THIS FEATURE INDUCING A BAND OF SNOW ACRS SOUTHEAST
MN INTO THE WESTERN U.P. OF MI.

&&

.SHORT TERM...TODAY AND TONIGHT...
AS THE ABOVE MENTIONED SFC WAVE ON THE BOUNDARY STARTS TO MIGRATE
NORTHEASTWARD AND DEEPEN SOME...THE LLVL BAROCLINICITY ALIGNED NE-SW
ACRS THE CWA WILL BE ABLE TO PUSH EASTWARD AS THE DAY PROGRESSES
MAKING IT EAST OF THE CWA PROBABLY JUST AFTER 18Z AS LONG AS
ADDITIONAL WEAK SFC WAVES ON THE BOUNDARY OFF TO THE SOUTHWEST OF
THE LOCAL AREA DON/T INTENSIFY AND HANG THE BOUNDARY UP. THE LLVL
WILL TRY TO SATURATE THIS MORNING ALONG AND POST-FRONTALLY...AND
SEVERAL SHORT RANGE MODELS INDUCE ANOTHER ROUND OF LOW TO MID LEVEL
WAA CONVERGENT WINGS AND FRONTOGENETICAL FORCED BANDS RIGHT THROUGH
THE HEART OF THE DVN CWA FROM 12Z THROUGH LATE MORNING. LARGE SCALE
UPPER JET COUPLING ALSO LOOKS WILL TAKE SHAPE OVER THE REGION TO ADD
TO THE LIFT CYCLE TODAY BETWEEN GRT LKS AND SOUTHERN PLAINS JET
STREAKS. FOR NOW WILL BANK ON THE LLVLS HAVING TROUBLE SATURATING
ENOUGH FOR MUCH MORE THAN JUST SCTRD SPRINKLES OUT OF VARYING DECKS
THIS MORNING. WILL ADD FLURRIES TO THE SPRINKLES IN THE FAR NORTH AS
THE BROAD ELEVATED SWATH OF FRONTOGENETICAL FORCING AHEAD OF THE
UPSTREAM DIGGING UPPER WAVE JUST CLIPS THE NORTHERN CWA LATER THIS
MORNING AND MAY NEED TO BE EXTENDED INTO THE EARLY AFTERNOON. BETTER
POST-FRONTAL/LLVL MOISTURE RETURN AND THUS A MORE ORGANIZED RAIN
THREAT STILL APPEARS WILL TAKE SHAPE OFF TO THE SOUTHEAST OF THE DVN
CWA BY LATE MORNING AND ESPECIALLY THIS AFTERNOON...BUT WILL KEEP
ONGOING SLIGHT CHC POPS FOR LIGHT RAIN GOING IN THE FAR EAST AND
SOUTHEAST. HIGH TEMPS WILL OCCUR THIS MORNING WITH JUST A LITTLE
REBOUND FROM CURRENT VALUES...AND THEN EXPECT A STEADY OR EVEN SLOW
FALL TREND IN THE AFTERNOON IN BUILDING LLVL CAA REGIME.

TONIGHT...SUBSIDENCE AND DEEPENING POST-FRONTAL NORTHWEST FLOW WILL
SCOUR OUT THE CLOUDS AND ANY LINGERING LIGHT PRECIP DURING THE
EVENING AND SET THE STAGE FRO ANOTHER CHILLY NIGHT. EXPECT SEVERAL
MID TO UPPER 20 DEGREE READINGS FOR MONDAY MORNING LOWS AND ONGOING
TEMP GRIDS LOOK ON TARGET.     ..12..

.LONG TERM...MONDAY THROUGH NEXT SATURDAY...
OUR SPLIT FLOW PATTERN CONTINUES...WITH THE NORTHERN STREAM SYSTEM
THAT BRUSHES OUR SOUTHEAST WITH PRECIPITATION TONIGHT SHIFTING OFF
TO THE EAST ON MONDAY...LEAVING THE AREA WITH NORTHWEST FLOW ALOFT
AND RIDGING AT THE SURFACE.  A WEAK SHORTWAVE WILL PASS THROUGH THIS
NORTHWEST FLOW ACROSS MINNESOTA AND WISCONSIN...BRINGING A LITTLE
LIGHT SNOW TO THOSE STATES. THIS PRECIPITATION SHOULD STAY WELL
OUTSIDE THE FORECAST AREA...THOUGH IT SHOULD BRING MORE CLOUDS TO
THE AREA. TEMPERATURES WILL REMAIN COOL ON MONDAY...THE INCREASED
CLOUDS OFFSETTING THE WARM AIR ADVECTION WHICH BEGINS ALOFT.  THE
WARM AIR ADVECTION MAKE MORE OF A DIFFERENCE ON TUESDAY...WHEN MAX
TEMPERATURES SHOULD RISE INTO THE UPPER 40S NORTH...TO MID 50S SOUTH
AHEAD OF A NEW COLD FRONT THAT THE NORTHERN STREAM DROPS INTO THE
AREA TUESDAY NIGHT AND EARLY WEDNESDAY.  HERE IS WHERE SOME
SIGNIFICANT MODEL DIFFERENCES APPEAR...AND RUN TO RUN CONSISTENCY
HAS BEEN LACKING.  THE CURRENT RUNS OF THE FORECAST MODELS TAKE THE
CUT OFF UPPER LEVEL LOW THAT HAS BEEN SLOWLY MOVING EAST ALONG THE
SOUTHERNMOST STATES OF THE CONUS...AND CONTINUE THE SEPARATION OF
THE NORTHERN AND SOUTHERN STREAMS...AT LEAST UNTIL VERY LATE IN THE
WEEK WHEN THE CUT OFF UPPER LOW GETS DRAWN NORTHEAST ACROSS THE
EASTERN CONUS AS IT FINALLY PHASES WITH THE NORTHERN STREAM.
HOWEVER...A FEW MODELS AS RECENT AS 28/00Z...PHASE THE STREAMS MUCH
EARLIER...AND BRING THE CUT OFF SOUTHERN STREAM UPPER LOW NORTHEAST
ALONG THE OHIO VALLEY...WHICH WOULD BRING PRECIPITATION TO THE
FORECAST AREA WEDNESDAY...WEDNESDAY NIGHT AND EARLY THURSDAY.
HOWEVER...THIS WAS ONLY A COUPLE OF THE MODELS...AND THEY HAVE SINCE
THEN MOVED MORE TOWARDS A SOUTHERN SOLUTION WHICH KEEPS ALL
PRECIPITATION OUT OF THE FORECAST AREA.  THUS...HAVE DRIED OUT THE
WEDNESDAY THROUGH THURSDAY TIME FRAME.  THIS SOUTHERN SOLUTION DUMPS
COLD AIR INTO THE REGION BY THURSDAY AND FRIDAY...WITH SOME LIGHT
SNOW OR FLURRIES ACCOMPANYING IT.  HAVE LOWERED TEMPERATURES
THURSDAY...AND THIS TREND WILL CONTINUE INTO FRIDAY AND SATURDAY...
THOUGH MODERATED SOMEWHAT.  HAVE ONLY INTRODUCED SLIGHT CHANCE POPS
TO THURSDAY AS A WEAK SHORTWAVE DROPS THROUGH THE CYCLONIC FLOW
ALOFT...AND HAVE LEFT THE REMAINING PERIODS DRY.      ..LE..

&&

.AVIATION...
WITH THE BOUNDARY IN THE VCNTY OF ALL TERMINALS AND THE LOWER LEVELS
TRYING TO SATURATE...A TRICKY CEILING AND VSBY FORECAST THROUGH AT
LEAST 18Z TODAY. WILL ADVERTISE MAINLY VFR AND MVFR CONDITIONS DUE
TO FOG AND CIGS WITH A CAREFUL WATCH ON THE IFR STRATUS JUST OFF TO
THE WEST AND THE POTENTIAL FOR THIS TO AFFECT ANY OF THE FCST
POINTS. SOME IFR FOG ALSO POSSIBLE IN CONVERGENT FIELDS NEAR THE
FRONT THROUGH 15Z ESPECIALLY AT CID AND DBQ. LIGHT SPRINKLES AND
VIRGA POSSIBLE AT ALL TERMINALS...AS WELL AS DRIZZLE OUT OF NAY
LOWER DECK THAT CAN MAKE IT INTO THE AREA. NORTHWEST WINDS SHOULD
INCREASE AFTER 18Z AS FRONT MAKES IT WAY EAST AND LEAD TO WIDESPREAD
VFR CONDITIONS BY LATE AFTERNOON AND OVERNIGHT.    ..12..

 &&

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

&&

$$

12/LE