FXUS63 KDVN 282039
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
235 PM CST SAT NOV 28 2009

.SYNOPSIS...
SFC ANALYSIS AT 2 PM SHOWS A BROAD SURFACE FRONT ACROSS THE FORECAST
AREA MOVING SOUTHEAST AT 10-15 MPH.  LIMITED MOISTURE AND WEAK FORCING
IS RESULTING IN CONTINUED MOSTLY SUNNY SKIES.  UPSTREAM SHOWS INCREASING
LOW LEVEL CONVERGENCE IN PLAINS SUPPORTING THIS FRONT BECOMING STRONGER
AS IT MOVES SE.  THIS WILL ALLOW MOISTURE TO POOL AND CLOUDS TO DEVELOP
ALONG AND BEHIND THE FRONT IN THE NEXT 12 TO 24 HOURS.  UPSTREAM UPPER
LEVEL ENERGY ALSO SUPPORTS THIS FRONT BECOMING MORE ACTIVE AS SW CONUS
UPPER CLOSED LOW MOVES EAST INTO TEXAS.  THIS KEY TO PROVIDING STRONGER
CONVERGENCE WITHIN THE NEXT 24 HOURS ALONG AND BEHIND STRENGTHENING COOL
FRONT.

&&

.SHORT TERM...TONIGHT AND SUNDAY...
TONIGHT...SKIES TO BECOME MOSTLY CLOUDY MAINLY IN THE OVERNIGHT HOURS
OVER MOST OR ALL THE AREA AS THE SLOW MOVING FRONT SLIDES SOUTHEAST.
KEPT DRIZZLE OR FOG OUT OF THE FORECAST AS MODEL LOW LEVELS ARE TOO
MOIST COMPARED TO ANALYSIS AND PASS FOR EVENING SHIFT TO MONITOR. LOWS
WENT SLIGHTLY COOLER IN NORTH HALF DUE TO DELAYED LOW CLOUD FORMATION.

SUNDAY...MOSTLY CLOUDY AND COOL WITH HIGHS UPPER 30S FAR NW TO LOW/MID
40S CENTRAL AND SOUTHEAST. AGAIN KEPT FOG AND DRIZZLE OUT OF FORECAST
FOR LATER SHIFTS TO DECIDE BUT LOCAL TOOLS AND TECHNIQUES DO SUGGEST
THIS IS POSSIBLE IN SE 1/4 TO 1/2.  KEPT SLIGHT CHANCE POPS IN FAR SE
SECTIONS WHERE MOISTURE IS THE GREATEST BUT AGAIN...DRIZZLE MAY BE MORE
APPLICABLE.  ..NICHOLS..

.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
NORTHERN STREAM TROF MOVES THROUGH THE AREA SUNDAY NIGHT/MONDAY.
ARRIVAL OF SAID TROF WILL PUSH ANY PRECIP EAST OF THE CWFA AND COOL
TEMPERATURES DOWN TO AROUND NORMAL AS NORTHWEST FLOW DEVELOPS. SPLIT
FLOW NATURE OF THE UPPER FLOW ACROSS THE CONUS INDICATES QUIET WX
WILL BE SEEN FROM SUNDAY NIGHT THROUGH TUESDAY NIGHT ACROSS THE
CWFA. LOW LEVEL RETURN FLOW THAT DEVELOPS ON TUESDAY WILL ALLOW
TEMPERATURES TO WARM ABOVE NORMAL AHEAD OF THE NEXT SYSTEM.

THE MID WEEK SYSTEM WILL BE INTERESTING. SPLIT FLOW IS CAUSING
DIFFERENCES IN PHASING OF THE NORTHERN AND SOUTHERN ENERGIES. THIS
PHASING ISSUE IS REFLECTED IN THE VARIOUS RUN TO RUN FLIPS OF THE
GLOBAL MODELS. THE 12Z RUNS NOW SUGGEST LESS PHASING CAUSING THE MID
WEEK SYSTEM TO PASS JUST SOUTH AND EAST OF THE AREA. IT WILL
PROBABLY WILL TAKE ANOTHER 48 HRS BEFORE THE MODELS CONVERGE ON AN
AGREED SOLUTION. FIGURING THAT SOME PHASING WILL OCCUR...WILL GO
WITH SCHC POPS FOR THE SOUTHEAST QUARTER/THIRD OF THE CWFA. COLD AIR
BEING DRAWN DOWN WITH THIS SYSTEM WILL RESULT IN ANY PRECIP CHANGING
OVER TO SNOW WED NIGHT.

AS THE UPPER LOW ROTATES ACROSS THE AREA THURSDAY/THURSDAY NIGHT H85
TEMPERATURES DROP INTO THE NEGATIVE DOUBLE DIGITS. STRONG CYCLONIC
FLOW COMBINED WITH THE COLD TEMPERATURES AND AN ARRIVING VORT MAX
SHOULD RESULT IN ANY PRECIP BEING IN THE FORM OF SNOW ON THURSDAY.
INTERESTINGLY...CONDENSATION PRESSURE DEFICITS IN ALL MODELS REMAIN
QUITE HIGH. SO...MINIMALLY FLURRIES SHOULD BE SEEN ON THURSDAY WITH
POSSIBLY SOME SHSN. FOR NOW WILL GO WITH SCHC POPS ACROSS THE
NORTHERN HALF OF THE CWFA. TEMPERATURES SHOULD BE WELL BELOW NORMAL
ON THURSDAY.

QUIET WX WITH BELOW NORMAL TEMPERATURES WILL BE SEEN ON FRIDAY.
FRIDAY NIGHT/SATURDAY IS ANOTHER QUESTION. GLOBAL MODELS SUGGEST
ANYTHING FROM AN ALBERTA CLIPPER OR A WEAK SOUTHERN STREAM SYSTEM TO
HIGH PRESSURE. DIFFERENCES CAN BE TRACED TO HOW THE MODELS PHASE THE
RESPECTIVE ENERGIES. FOR NOW...WILL GO WITH A DRY FCST.   ..08..

&&

.AVIATION...
KEPT VFR CONDITIONS AND FAIR SKIES THROUGH 06Z ALL TERMINALS. BETWEEN
06Z AND 12Z MVFR CONDITIONS TO DEVELOP ALL TERMINALS BEHIND SLOW MOVING
COOL FRONT WITH CIGS 1-3K AGL AND VSBYS 2 TO 5 MILES IN LIGHT FOG AND
HAZE BY MID DAY.   ..NICHOLS..

 &&

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

&&

$$

NICHOLS/08