FXUS63 KSGF 042309
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
509 PM CST FRI DEC 4 2009

...UPDATE TO AVIATION...

.DISCUSSION...

MAIN FORECAST FOCUS IN THIS PACKAGE WILL DEAL WITH ANOTHER CHILLY
NIGHT TONIGHT. ATTENTION THEN TURNS TO CHANCES FOR PRECIPITATION
AND POSSIBLY WINTRY PRECIPITATION SUNDAY NIGHT AND AGAIN TUESDAY
INTO WEDNESDAY.

SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...

CURRENTLY AN UPPER LEVEL TROUGH ALONG WITH A COLD AIRMASS IS PARKED
OVER THE CENTRAL CONUS. DEWPOINTS ARE IN THE LOWER TEENS TO THE
UPPER SIGNAL DIGITS ACROSS THE AREA THIS AFTERNOON. THESE SURFACE
CONDITIONS ALONG WITH A CLEARING SKY AND LIGHT WINDS THIS
EVENING...WILL RESULT IN TEMPERATURES QUICKLY COOLING AFTER
SUNSET. SURFACE WINDS WILL SWING AROUND TO THE SOUTH FROM WEST TO
EAST OVERNIGHT AS THE TROUGH AXIS PUSHES TO THE EAST. THESE
SOUTHERLY WINDS SHOULD HELP TEMPERATURES STEADY OUT
OVERNIGHT...BUT WITH THE COOL START...I HAVE UNDER CUT MOS
GUIDANCE AND WENT WITH LOWS IN THE UPPER TEENS TONIGHT.

A SLIGHTLY WARMER AIRMASS WILL WORK INTO THE AREA TOMORROW AND 
SUNDAY...HOWEVER HIGHS WILL REMAIN BELOW NORMAL WITH HIGHS IN THE
AROUND 40 TO THE MID 40S. AN UPPER LEVEL SHORTWAVE TROUGH WILL
QUICKLY SWING OUT OF THE CENTRAL PLAINS AND THROUGH THE AREA LATE
SUNDAY INTO MONDAY. INITIALLY LIGHT RAIN WILL DEVELOP AHEAD OF THE
SYSTEM LATE SUNDAY AFTERNOON AND AS TEMPERATURES COOL SUNDAY
EVENING INTO SUNDAY NIGHT LIGHT FREEZING DRIZZLE WILL BE POSSIBLE.
THERE WILL BE LOW LEVEL MOISTURE ASSOCIATED WITH THIS FEATURE...HOWEVER
MID LEVEL MOISTURE WILL BE LACKING. THEREFORE...THERE IS A LACK OF
ICE CRYSTAL DEVELOPMENT WHICH WILL LIMIT SNOW. CANNOT RULE OUT SOME
SEEDER FEEDER PROCESSES ACROSS THE NORTHERN AND WESTERN CWA...SO
THERE MAY BE SOME SNOW MIXING IN. HOWEVER ACCUMULATING SNOW WILL
LIKELY REMAIN WELL WEST AND NORTH OF THE AREA. THE QUESTION WITH
THIS SYSTEM IS WHETHER THE COLDER SURFACE TEMPERATURES SPREAD
ACROSS THE REGION WHILE LIGHT RAIN OR DRIZZLE CONTINUES AND FOR
HOW LONG. CURRENT THINKING IS THERE WILL BE PERIODS OF LIGHT
FREEZING DRIZZLE ACROSS PORTIONS OF THE AREA SUNDAY EVENING AND
NIGHT...WITH VERY LITTLE TO ANY ACCUMULATION.

WISE

LONG TERM (MONDAY THROUGH FRIDAY)...

COLD AND UNSETTLED WEATHER TO CONTINUE INTO NEXT WEEK. MEDIUM RANGE
MODELS CONTINUE TO ADVERTISE A POTENTIAL WINTER STORM SOMEWHERE
OVER THE CENTRAL U.S. THE LATEST RUN OF THE GFS MODELS TRENDED
FARTHER NORTH WITH A DEEP SURFACE LOW. THIS WOULD RESULT IN WARMER
TEMPERATURES ACROSS SOUTHERN MISSOURI AND KEEP THE MAJORITY OF THE
SNOW TO THE NORTH. THE ECMWF TRENDED A BIT FARTHER SOUTH WITH A
MORE FAVORABLE TRACK FOR SNOW ACROSS THE OZARKS. ULTIMATELY THERE
ARE MANY UNCERTAINTIES THAT STILL EXIST REGARDING THE TRACK AND
STRENGTH OF THIS SYSTEM. AT THIS TIME IT APPEARS PRECIPITATION
PERHAPS IN THE FORM OF A WINTRY MIX WILL DEVELOP EARLY TUESDAY
THEN MAY TRANSITION TO RAIN DURING THE DAY. PRECIPITATION WOULD
THEN TRANSITION TO SNOW TUESDAY NIGHT AS THE STORM SYSTEM LIFTS
OUT. AGAIN PRECIPITATION TYPE AND ACCUMULATIONS ARE YET TO BE
DETERMINED...BUT THE FORECAST SHOULD BE CLOSELY MONITORED FOR THE
POTENTIAL FOR ACCUMULATING WINTER PRECIPITATION NEXT WEEK.

FOSTER

&&

.AVIATION...

FOR THE 00Z TAF PACKAGE...VFR CONDITIONS ARE EXPECTED FOR THE NEXT
24 HOURS AND BEYOND. HIGH PRESSURE WILL MOVE SOUTH OF THE AREA
TONIGHT...RESULTING IN A GRADUAL INCREASE IN SOUTHERLY WINDS
OVERNIGHT. THESE WINDS WILL BECOME GUSTY DURING THE DAYLIGHT HOURS
OF SATURDAY. HIGH CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST
LATE IN THE FORECAST CYCLE AS A STORM SYSTEM BEGINS TO APPROACH
FROM THE WEST.

GAGAN

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$