FXUS63 KSGF 060529
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1129 PM CST SAT DEC 5 2009

...UPDATE TO AVIATION...

.DISCUSSION...

FORECAST CONCERNS CONTINUE TO REVOLVE AROUND PRECIP CHANCES SUNDAY
EVENING...FOLLOWED BY TIMING AND PRECIP TYPE TUESDAY INTO
WEDNESDAY.

SHORT TERM (TONIGHT THROUGH TUESDAY)...

CURRENTLY...SURFACE HIGH PRESSURE OVER NORTHEASTERN ARKANSAS WITH
SOUTHERLY WINDS OVER THE CWA THIS AFTERNOON. TEMPERATURES HAVE
CLIMBED INTO THE UPPER 30S AND LOW 40S UNDER SUNNY SKIES. WATER
VAPOR IMAGERY CONTINUES TO SHOW A SOUTHWARD DIGGING OF THE LOW
PRESSURE AREA OVER THE NORTHERN ROCKIES THIS AFTERNOON...WHILE A
PLUME OF UPPER LEVEL MOISTURE CONTINUES TO STREAM EAST OUT OF THE
DESERT SOUTHWEST.

FOR OVERNIGHT AND SUNDAY...DRY WEATHER EXPECTED WITH LOWS IN THE
LOW TO MID 20S...SIGNIFICANTLY WARMER THAN WHAT WE HAVE BEEN
SEEING THE PAST FEW MORNINGS. SOUTHERLY WINDS RAISE 850/925MB
TEMPERATURES FROM -8C/-3C SEEN THIS MORNING TO -2C/-1C SUNDAY
MORNING. GENERALLY FOLLOWED MET GUIDANCE ON TEMPERATURES WITH
SOME SLIGHT BIAS CORRECTIONS ON BOTH LOWS AND HIGHS FOR SUNDAY.
SHOULD SEE A STEADILY THICKENING OF MID AND HIGH LEVEL CLOUDINESS
THROUGH THE DAY SUNDAY WHICH MAY OFFSET THE WARM AIR ADVECTION.
SHOULD WE SEE SOME CLOUD BREAKS LATE SUNDAY MORNING INTO THE
AFTERNOON...TEMPERATURES COULD BE A FEW DEGREES WARMER THAN WHAT
WE HAVE GOING. ESPECIALLY IN OUR EASTERN COUNTIES WHERE THE WAA
WILL BE MOST SIGNIFICANT. BY SUNDAY AFTERNOON...MODELS SHOWING
SURFACE LOW PRESSURE MOVING FROM THE TEXAS PANHANDLE INTO OKLAHOMA
WITH A WARM FRONT PUSHING INTO OUR SOUTHERN COUNTIES. ALONG WITH
THIS THE WRF SHOWS STRONG BROAD SCALE ISENTROPIC LIFT SUNDAY
AFTERNOON THAT SHOULD ENHANCE PRECIP DEVELOPMENT IN THE FORM OF
LIGHT RAIN.

BY SUNDAY EVENING INTO TUESDAY MORNING...SURFACE LOW FORECAST TO
TRACK THROUGH THE STATE SUNDAY EVENING WITH THE ASSOCIATED COLD
FRONT PUSHING THROUGH THE AREA AFTER MIDNIGHT 850MB TEMPERATURES
DROP SIGNIFICANTLY DOWN TO AROUND -6C ACROSS CENTRAL MISSOURI.
MODEL SOUNDINGS SHOWING MID LEVELS DRY BEHIND THE FRONT...BUT
SIGNIFICANT LOW LEVEL MOISTURE TO REMAIN. HAVE GONE AHEAD AND
CONTINUED THE MIX OF DRIZZLE/FREEZING DRIZZLE IN THE FORECAST
INTO MONDAY MORNING BEFORE THE SURFACE LOW TRACKS NORTHEAST OF
THE AREA. A QUICK TRANSITION AS WINDS SHIFT TO THE SOUTH AND
SOUTHEAST MONDAY EVENING INTO TUESDAY AHEAD OF THE STRONG SURFACE
LOW FORECAST TO MOVE INTO WESTERN KANSAS TUESDAY MORNING.

CLAYCOMB

LONG TERM (TUESDAY THROUGH SATURDAY)...

MEDIUM RANGE MODELS REMAIN CONSISTENT IN BRINGING A WINTER STORM
TO PORTIONS OF THE CENTRAL U.S. THIS COMING WEEK BUT DIFFER ON THE
DETAILS. THE UPPER TROUGH NOW DIGGING ALONG THE WEST COAST WILL
SWING EAST ACROSS THE ROCKIES EARLY NEXT WEEK. THE ASSOCIATED
SURFACE LOW WILL TRACK FROM THE SOUTHERN ROCKIES INTO MISSOURI ON
TUESDAY. UNCERTAINTY EXISTS ON THE TIMING AND DEPTH OF THE UPPER
TROUGH...AND THE TRACK OF THE SURFACE LOW ALL OF WHICH WILL IMPACT
PRECIPITATION TYPES AND AMOUNTS. THE GFS MODEL MAINTAINS A
SOLUTION FARTHER NORTH THAN THE EUROPEAN AND KEEPS THE HEAVIEST
SNOW TO THE NORTH ACROSS NORTHERN KANSAS AND MISSOURI. THE
EUROPEAN MODEL TRACKS THE SURFACE LOW ACROSS FAR NORTHERN ARKANSAS
WHICH WOULD PLACE SOUTHERN MISSOURI AND SOUTHEAST KANSAS IN A MORE
FAVORABLE LOCATION FOR RECEIVING ACCUMULATING SNOW.

ALSO IN QUESTION IS THE THERMAL PROFILE AT THE ONSET OF 
PRECIPITATION LATE MONDAY NIGHT AND TUESDAY MORNING. POCKETS OF 
FREEZING SURFACE TEMPERATURES COULD RESULT IN A BRIEF PERIOD OF 
FREEZING RAIN. SNOW IS ALSO POSSIBLE EARLY TUESDAY BEFORE 
TRANSITIONING TO RAIN AS WARM AIR ADVECTION INCREASES AHEAD OF 
THE APPROACHING SYSTEM. PRECIPITATION WILL LIKELY TRANSITION TO
SNOW FROM WEST TO EAST TUESDAY NIGHT.

AT THIS TIME IT APPEARS THE HIGHEST CHANCE FOR ACCUMULATING SNOW 
EXISTS FROM SOUTHEAST KANSAS INTO CENTRAL MISSOURI WITH HIGHER 
AMOUNTS FARTHER NORTH ACROSS NORTHERN KANSAS AND MISSOURI. GIVEN THE 
UNCERTAINTY ON THE EXACT TRACK OF THIS WINTER STORM AND RESULTING 
ACCUMULATIONS THE LATEST WEATHER INFORMATION SHOULD BE CLOSELY 
MONITORED.

FOSTER

&&

.AVIATION...

FOR THE 06Z TAF PACKAGE...VFR CONDITIONS WILL PERSIST THROUGH
SUNDAY AFTERNOON. THE POTENTIAL FOR MVFR CIG/VIS EXISTS BEGINNING
SUNDAY EVENING. A QUICK MOVING STORM SYSTEM WILL APPROACH FROM THE
WEST. MID AND HIGH LEVEL MOISTURE WILL CONTINUE TO INCREASE...
BUILDING DOWN GRADUALLY SUNDAY AFTERNOON. MVFR CIGS WILL BE
POSSIBLE AFTER SUNSET SUNDAY AS THE COLD FRONT APPROACHES...WITH
BETTER POTENTIAL POST FRONTAL NEAR THE END OF THE TAF CYCLE. DEEP
MOISTURE IS LACKING WITH THIS SYSTEM...AS A RESULT DRIZZLE IS
EXPECTED. TEMPERATURES WILL FLIRT WITH THE FREEZING MARK BY THE
END OF THE TAF CYCLE AND THOSE WITH FLYING INTERESTS INTO
JLN/SGF/BBG NEED TO KEEP CLOSE TABS ON THE POTENTIAL FOR SOME
FREEZING DRIZZLE SUNDAY NIGHT.

GAGAN

&&

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

$$