FXUS63 KDVN 280923
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
320 AM CST SAT NOV 28 2009

.SYNOPSIS...
LATEST SFC ANALYSIS WAS INDICATING A WEAK SFC WAVE ACRS NORTHWEST IA
WITH ASSOCIATED WARM FRONT JUTTING OFF TO THE SOUTHEAST OF IT ACRS
SOUTHEAST IA AND INTO WEST CENTRAL IL. ANOTHER SFC WAVE AND TROF
COMPLEX WAS NOTED BISECTING MN FROM NORTH TO SOUTH...AS WELL AS
OTHER TROFFING EXTENDING OFF TO THE SOUTHWEST ACRS THE CENTRAL
PLAINS. SFC PRESSURE FALLS WERE MAINTAINING TO THE LEE OF THESE
FEATURES INCLUDING THE WARM FRONT WERE KEEPING AT LEAST 5 KT WINDS
GOING ACRS MUCH OF THE AREA WHICH MAY BE HELPING TO ALLEVIATE MUCH OF
ANY SUBSTANTIAL FOG FORMATION THROUGH NOW. ALOFT...BROAD UPPER
RIDGING ACRS MUCH OF THE NORTHERN HALF OF THE CENTRAL CONUS WAS
STARTING TO FLATTEN AS A W/V IMAGERY INDICATED NORTHERN STREAM WAVE
ACRS MT INTO SASKATCHEWAN WAS SEEN TRYING TO DIG SOUTHEASTWARD.

&&

.SHORT TERM...TODAY AND TONIGHT...
FOG WORTH ZONE MENTION REALLY HAS NOT TAKEN OFF...BUT WILL KEEP AT
LEAST PATCHY WORDING GOING INTO EARLY MORNING ESPECIALLY ALONG AND
JUST NORTH OF THE WARM FRONT AS PRIME WINDOW STILL HAS NOT BEEN
REACHED. AS THE ABOVE MENTIONED WAVE ENERGY ACRS THE NORTHERN
ROCKIES DIGS ACRS THE NORTHERN PLAINS THROUGH THIS EVENING...MAIN
STEERING FLOW WILL CONTINUE TO FLATTEN TO THE EAST OF IT AND
UPSTREAM SFC WAVE AND TROF/FRONT COMPLEX WILL GET SHUNTED ACRS THE
WESTERN CWA BY 00Z SUNDAY IN A NORTHEAST TO SOUTHWEST FASHION. LLVL
THERMAL RIDGE GETTING DRAGGED UP ACRS THE CWA CURRENTLY AHEAD OH THE
UPSTREAM FRONT AND WILL BE IN PLACE FOR DIURNAL MIXING TODAY. BUT
THE EXTENT OF THAT MIXING STILL SOMEWHAT AT QUESTION FOR WARM UP
POTENTIAL TODAY AS FCST MODEL SOUNDINGS STILL SUGGEST MEAGER MIXING
DEPTH OF H95 TO H925 MB AT BEST. WEAK/SHALLOW MIXING OF THE MODELS
SUGGEST HIGHS ONLY IN THE LOW TO MID 50S TODAY CWA-WIDE...BUT ANY
DEEPER MIXING JUST ABOVE 925 MB WOULD SUPPORT WIDESPREAD 52 TO 62
DEGREE TEMPS FROM NORTHEAST TO SOUTHWEST ACRS THE LOCAL FCST AREA.
DO FAVOR THE DEEPER MIXING AND THUS WARMER REGIME ADVERTISED BY THE
MAV AND WILL LEAN TOWARD THIS WARMER GUIDANCE. ONGOING HIGHS
ALREADY IN GOOF AGREEMENT WITH THE NEW MAV GUIDANCE AND WILL CHANGE
LITTLE. VERY DRY COLUMN/CONDITIONS WITH JUST MAYBE SOME PASSING CI
AGAIN TO ENSURE PLENTY OF INSOLATION FOR OUR SATURDAY.

TONIGHT...THE DIGGING UPSTREAM WAVE WILL CONTINUE TO INDUCE
CYCLOGENESIS ON NORTHERN EXTENT OF THE PASSING BOUNDARY ACRS WI INTO
MI. THE REST OF THE FRONT WILL CONTINUE TO SAG SLOWLY THROUGH THE
DVN CWA THROUGH SUNDAY MORNING AND PROBABLY NOT MAKING IT THROUGH
BY THEN SLOWED AND HANGING ALMOST PARALLEL WITH WSW MEAN STEERING
FLOW. LLVL MOISTURE RETURN OFF THE WESTERN GULF WILL START UP THE
SOUTHERN PLAINS AND INTO MO TONIGHT INTO SUNDAY MORNING...BUT STILL
HOLD OFF TO THE SOUTHWEST OF THE DVN CWA TO LIMIT ANY CHC FOR ENOUGH
LLVL SATURATION TO PRODUCE PRECIP IN THE INCREASING LLVL CONVERGENCE
ALONG THE FRONT. BETTER LLVL MOISTURE POOLING ALONG THE BOUNDARY OFF
TO THE SOUTH/SOUTHWEST OF THE CWA THROUGH 12Z ANYWAY. JUST SOME
INCREASE IN MID AND HIGH LEVEL CLOUDS AFTER 06Z SUNDAY. EXPECT
WIDESPREAD LOW TO MID 30 LOW TEMPS TONIGHT WITH AREAS ALONG AND TO
THE EAST OF THE BOUNDARY BEING HELD UP IN THE MID TO POSSIBLY UPPER
30S.     ..12..

.LONG TERM...SUNDAY THROUGH NEXT FRIDAY...
FOR A RELATIVELY ACTIVE WEATHER PATTERN ACROSS THE CONUS...WE HAVE A
RELATIVELY QUIET WEATHER FORECAST.  THE COLD FRONT THAT DROPS
THROUGH THE AREA LATER TODAY WILL BE SITTING JUST TO THE SOUTHEAST
OF THE AREA ON SUNDAY.  THE UPPER LEVEL PATTERN WILL BE SPLIT INTO A
NORTHERN AND SOUTHERN STREAM SYSTEM...WITH THE NORTHERN STREAM
SHORTWAVE AS OF SUNDAY MORNING WILL BE MOVING ACROSS MINNESOTA...AND
WILL HELP TO CONTINUE TO PUSH THE COLD FRONT FARTHER EAST.  THE
SOUTHERN STREAM HAS A CUT OFF LOW OUT OVER SOUTHERN CALIFORNIA. THE
NORTHERN STREAM WAVE WILL BE ABLE TO PULL SOME MOISTURE UP FROM THE
GULF WITH THE SOUTHERN SYSTEM MUCH FARTHER WEST...AND A BAND OF
OVERRUNNING PRECIPITATION SHOULD FORM ON THE NORTHERN SIDE OF THE
FRONT...EXTENDING FROM OKLAHOMA UP ACROSS MISSOURI AND ILLINOIS.
THIS MAY CATCH OUR SOUTHEASTERN COUNTIES ON SUNDAY...AND HAVE
CONTINUED THE SLIGHT CHANCE POPS WE HAVE GOING FOR THE DAYTIME. BY
EVENING THIS BAND OF PRECIPITATION SHOULD HAVE SHIFTED FAR ENOUGH
SOUTHEAST THAT OUR AREA WILL BE OUT OF THE RAINFALL.  SUNDAY NIGHT
SHOULD BE A COLD NIGHT...WITH 850MB TEMPS DOWN AROUND -5C.  IF WE
CAN CLEAR OFF WE WILL BE BACK DOWN INTO THE LOW TO MID 20S.  AFTER
THIS...THE SPLIT UPPER LEVEL FLOW CONTINUES...WITH THE CUT OFF UPPER
LOW IN THE SOUTHERN STREAM MOVING VERY SLOWLY EAST...AND A MORE
ACTIVE NORTHERN STREAM BRINGING ANOTHER SHORTWAVE ACROSS THE UPPER
MIDWEST IN THE TUESDAY-WEDNESDAY TIME FRAME.  BY THIS TIME RANGE WE
HAVE SOME FAIRLY SIGNIFICANT DIFFERENCES BETWEEN MODELS...AND SOME
PROBLEMS WITH RUN TO RUN CONSISTENCY.  ECMWF SEEMS TO BE DOING THE
BEST...AND HAVE TRIED TO BASE FORECAST MAINLY OFF IT. TEMPERATURES
MONDAY AND TUESDAY WILL START OUT NEAR NORMAL MONDAY...BUT SHOULD
WARM SIGNIFICANTLY FOR TUESDAY WITH WARM AIR ADVECTION ONGOING
ALOFT.  A NEW COLD FRONT GETS DRAGGED ACROSS THE AREA ON WEDNESDAY
...BUT WITH LITTLE MOISTURE AND PRECIPITATION CHANCES LOOK PRETTY
SCANT EVEN WHEN THE WRAP-AROUND DEFORMATION ZONE PRECIPITATION WOULD
SWING ACROSS THE AREA WEDNESDAY NIGHT. THUS...HAVE GONE WITH
WEDNESDAY AND WEDNESDAY NIGHT SLIGHT CHANCE POPS...AND WE WILL HAVE
TO CONTINUE TO RE-EVALUATE WITH SUBSEQUENT MODEL RUNS.  TEMPERATURES
DROP AGAIN FOR WEDNESDAY AND WEDNESDAY NIGHT WITH ANOTHER SHOT OF
COLD AIR AT 850MB...BRINGING VALUES DOWN TO AROUND -10C.  THIS TREND
SHOULD CONTINUE INTO THURSDAY...BUT TEMPERATURES SHOULD MODERATE
AGAIN BY FRIDAY.     ..LE..

&&

.AVIATION...
STILL EXPECT SOME MVFR FOG TO POSSIBLY IMPACT THE TERMINALS THROUGH
15Z IN VCNTY OF WARM FRONT ESPECIALLY AT CID AND MLI...BUT ENOUGH
SFC FLOW TO PROBABLY LIMIT MUCH OF ANY IFR LEVEL FOG. THEN ANOTHER
MAINLY VFR TAF PERIOD WITH VARYING BOUTS OF CI AND VARYING BUT
LIGHT SFC WINDS IN VCNTY OF SFC BOUNDARY. FRONTAL PASSAGE WILL
INDUCE BRISKER NORTHWEST FLOW AT DBQ AND CID AFTER 06Z SUNDAY.
..12..

&&

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

&&

$$

12/LE