FXUS63 KSGF 021723
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1123 AM CST WED DEC 2 2009

.UPDATE...

A COLDER AIRMASS CONTINUED TO SPREAD INTO THE OZARKS AND OSAGE
PLAINS AT LATE MORNING IN INCREASING NORTHWEST WINDS. A POTENT
SHORTWAVE TROUGH WAS TRACKING ACROSS THE LOWER MISSISSIPPI RIVER
VALLEY WITH AN ACCOMPANYING SURFACE LOW WAS LOCATED ACROSS
NORTHERN MISSISSIPPI. LIGHT PRECIPITATION HAD SPREAD INTO SOUTH
CENTRAL MISSOURI WHERE LIGHT RAIN HAD BEEN MIXED WITH SLEET AT
TIMES THIS MORNING. ANOTHER BAND OF PRECIPITATION WAS DEVELOPING
FROM SOUTHEAST KANSAS INTO WEST CENTRAL MISSOURI WITHIN AN AXIS OF
MID LEVEL FRONTOGENETICAL FORCING ALONG THE DEVELOPING DEFORMATION
ZONE NORTH OF THE SHORTWAVE TROUGH.

LIGHT PRECIPITATION WILL AFFECT MUCH OF THE AREA THIS AFTERNOON
AS THE DEFORMATION ZONE TRANSITIONS TO THE EAST. RAIN WILL BECOME
MIXED WITH OR CHANGE TO LIGHT SNOW AS THE THE LOWER ATMOSPHERIC
COLUMN CONTINUES TO COOL. LIGHT PRECIPITATION...ABOVE FREEZING AIR
TEMPERATURES AND RELATIVELY WARM GROUND TEMPERATURES WILL ALL BE
INHIBITORS TO ACCUMULATION. ONLY SOME VERY MINOR ACCUMULATION IS
POSSIBLE ON GRASSY SURFACES LATE THIS AFTERNOON.

FOSTER

&&

.DISCUSSION...

THE MAIN FORECAST CONCERNS REMAIN PRECIPITATION AREAL
EXTENT...AMOUNTS...AND TO SOME EXTENT PRECIP TYPE WITH THE STRONG
UPPER LEVEL LOW MOVING NE FROM TX THROUGH THE LOWER/MID MS VLY BY
LATE AFTERNOON/EARLY EVENING. COLD TEMPERATURES ARE A CONCERN TO
END THE WORK WEEK.

LIFT AND RESULTANT CLOUDS ARE INCREASING OVER EASTERN OK AND WESTERN
AR ATTM IN ADVANCE OF A STRONG UPPER LOW CENTERED OVER CNTRL TX
AT 07Z. WEAK RADAR RETURNS ARE OCCURRING AS FAR NORTH AS NE
OK...BUT DRY AIR IN THE LOWEST 0-3 KM IS LIMITING THE NORTHERN
EXTENT TO SFC PRECIP TO THE SOUTHEAST QUARTER OF OK. RADAR RETURNS
ARE ALSO INCREASING IN A NARROW BAND OVER EASTERN KS AHEAD OF A
NORTHERN STREAM SHORTWAVE...BUT AGAIN PRECIP REACHING THE GROUND
WILL BE LIMITED BY LOW LEVEL DRY AIR. 

IN GENERAL...LARGE SCALE LIFT WILL INCREASE AFTER 12Z AND PEAK AT
18Z-21Z OVER THE EASTERN CWFA AS THE UPPER LOW MOVES THROUGH FAR
SOUTHEAST MO BOOT HEEL. LIFT OVER THE WESTERN CWFA WILL BE WEAKER
OVERALL...AND LIGHT PRECIPITATION FALLING TO INTO THE DRY LAYER
MAY NOT BE ENOUGH TO SATURATE THE LOWER LEVELS...ESPECIALLY SINCE
DRY AIR WILL CONTINUE TO BE PUMPED SOUTH INTO THE REGION TODAY.
OVER THE EASTERN CWFA...ESPECIALLY SOUTH CENTRAL MO...PROGGED GFS
CROSS SECTIONS INDICATE DEEP LIFT AND MORE ABUNDANT MOISTURE TO
PRODUCE GOOD CHANCES FOR RAIN. THE W-E GRADIENT OF RAINFALL
AMOUNTS WILL LIKELY BE FAIRLY ABRUPT. FOR POPS...HAVE NEARLY
90-100 POPS OVER SOUTH CENTRAL MO TO TEENS AND 20S OVER SOUTHEAST
KS FOR TODAY. PRECIP CHANCES RAPIDLY DECREASE OVER THE EASTERN
CWFA LATE THIS AFTERNOON AS THE UPPER LOW QUICKLY BEGIN TO EXIT
THE REGION. A DECENT PRESSURE GRADIENT WILL EXIST WEST OF THE
DEEPENING SFC LOW THIS AFTERNOON AND EVENING WITH BLUSTERY
CONDITIONS.

PRECIP TYPE IS STILL A CONCERN. WHERE LIFT/PRECIP CAN SATURATE THE
LOWER LEVELS...EVAPORATIVE COOLING AND GRADUALLY INCREASING COLD
AIR ADVECTION WILL HAVE A CHANCE TO TURN RAIN INTO WET SNOW IN
SOME PLACES DURING THE MID/LATE AFTERNOON. THE WINDOW FOR THIS IS
BRIEF AND NOT LOOKING FOR MUCH...IF ANY...IMPACT IN AREAS WHERE
SNOW CAN OCCUR.

COLD TEMPERATURES WILL BE THE MAIN STORY TO END THE WEEK. 850MB
TEMPS GENERALLY RANGE FROM -10 TO -12 DEG C THU AND FRI WITH SFC
TEMPERATURES STRUGGLING IN THE 30S FOR HIGHS. A WEAK SHORTWAVE WILL
MOVE THROUGH THE REGION FRI NIGHT AND A STRONGER SYSTEM WILL MOVE
THROUGH THE GULF COAST REGION AND SOUTHEAST U.S. OVER THE WEEKEND
WITH PRECIP REMAINING WELL TO THE SOUTH. WE WILL SEE A MODEST
WARM UP OVER THE WEEKEND AS A LOW AMPLITUDE UPPER RIDGE MOVES
THROUGH THE CNTRL PLAINS. A STRONGLY ZONAL MID LATITUDE UPPER FLOW
PATTERN WILL REMAIN ESTABLISHED OVER SOUTHERN CONUS. COULD SEE
SOME LIGHT SNOW OR RAIN SUNDAY NIGHT AS A QUICK MOVING SHORTWAVE
APPROACHES. DSA

&&

.AVIATION...

CEILINGS WILL GRADUALLY LOWER THIS AFTERNOON AS THE LOWER
ATMOSPHERE MOISTENS. MVFR CEILINGS WILL LIKELY DEVELOP AT AREA
TERMINALS DURING THE AFTERNOON. INTERMITTENT LIGHT PRECIPITATION
IN THE FORM OF RAIN AND SNOW IS EXPECTED WHICH WILL LOWER THE
VISIBILITY FOR BRIEF PERIODS. ANY IFR CONDITIONS WILL BE LOCALIZED
IN NATURE. A STRENGTHENING PRESSURE GRADIENT BETWEEN SURFACE HIGH
PRESSURE OVER THE HIGH PLAINS AND LOW PRESSURE IN MISSISSIPPI WILL
RESULT IN GUSTY NORTHWEST WINDS. CLEARING SKIES AND A RETURN TO
VFR CONDITIONS WILL OCCUR TONIGHT.

FOSTER

&&

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

$$