FXUS63 KSGF 070530
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1130 PM CST SUN DEC 6 2009

...UPDATE TO AVIATION...

.UPDATE...

VAST MAJORITY OF PRECIP HAS EXITED STAGE EAST. WILL STILL DEAL
WITH PATCHY DRIZZLE OVERNIGHT...WITH THE POTENTIAL FOR LIGHT
FREEZING DRIZZLE AS TEMPS SLOWLY DROP TO AROUND FREEZING POST
FRONTAL. BRIDGES AND OVERPASSES WILL BE AT RISK FOR A FEW SLICK
SPOTS...BUT DRIZZLE DOES NOT LOOK TO BE ALL THAT WIDESPREAD.

GAGAN

&&

.DISCUSSION...

FORECAST CHALLENGES CONTINUE TO REVOLVE AROUND PRECIPITATION
CHANCES TONIGHT AND PRECIPITATION TYPE FOR THE STORM SYSTEM MID
WEEK.

SHORT TERM (TONIGHT THROUGH MONDAY)...

CURRENTLY...MOISTURE PLUME FROM DESERT SOUTHWEST CONTINUES TO MOVE
INTO THE AREA THIS AFTERNOON AS SURFACE LOW PRESSURE CONTINUES TO
DEVELOP NEAR THE TEXAS/OKLAHOMA PANHANDLE AREA. QUITE A LARGE AREA
OF STRATOCU HAS DEVELOPED ACROSS EASTERN TEXAS...MUCH OF OKLAHOMA
AND KANSAS...SOUTH OF A WARM FRONT EXTENDING FROM THE LOW
NORTHEAST INTO NORTHWESTERN MISSOURI. FURTHER WEST...OUR TUESDAY
SYSTEM CONTINUES TO DIG SOUTH INTO NORTHERN CALIFORNIA AND NEVADA.

FOR TONIGHT AND MONDAY...WITH BROAD SCALE ISENTROPIC UPGLIDE...COULD
STILL SEE SOME LIGHT RAIN/DRIZZLE ACROSS MUCH OF THE AREA...THOUGH
ACCUMULATIONS ARE EXPECTED TO BE MINOR. SURFACE LOW AND ASSOCIATED
COLD FRONT TO PUSH INTO SOUTHWEST MISSOURI AFTER MIDNIGHT AND
THROUGH THE REMAINDER OF THE CWA BY MONDAY MORNING. PRETTY COLD
TEMPERATURES BEHIND THE FRONT DO NOT LINE UP WITH THE PRECIP...SO
THINK FOR THE MOST PART...ANY PRECIP THAT DOES FALL WILL BE
LIQUID. CAN NOT RULE OUT SOME FREEZING DRIZZLE BEHIND THE FRONT IN
THE STRATUS...SO CONTINUED PATCHY FREEZING DRIZZLE THROUGH MONDAY
MORNING. MONDAY HIGHS WILL STRUGGLE TO GET OUT OF THE MID 30S
THROUGH THE DAY AS COLD AIR ADVECTION AND NORTHWEST WINDS USHER IN
COLDER LOW LEVEL TEMPERATURES.

CLAYCOMB

LONG TERM (MONDAY NIGHT THROUGH SUNDAY)...

FIRST SIGNIFICANT WINTER STORM OF THE SEASON POISED TO IMPACT PORTIONS
OF THE CENTRAL PLAINS AND MIDWEST THIS WEEK. A POTENT SHORTWAVE TROUGH
NOW OFF OF THE OREGON COAST WILL SWING AROUND THE DEVELOPING WESTERN
LONGWAVE TROUGH. WHILE THERE REMAINS SOME UNCERTAINTY ON THE
TIMING AND TRAJECTORY OF THIS SYSTEM AS IT EJECTS NORTHEAST MODELS
ARE IN GOOD AGREEMENT IN THE OVERALL EVOLUTION OF THIS SYSTEM.
EXPECT PRECIPITATION TO DEVELOP TUESDAY MORNING AS WARM AIR
ADVECTION/ISENTROPIC ASCENT DEVELOPS IN RESPONSE TO HEIGHT FALLS
AND SURFACE CYCLOGENESIS OVER THE PLAINS. THERMAL PROFILES
SUGGEST PRECIPITATION MAY BEGIN AS A WINTRY MIX AT THE ONSET OF
PRECIPITATION. LITTLE IF ANY ACCUMULATION IS EXPECTED AS
TEMPERATURES WILL BE SLOWLY CLIMBING. PRECIPITATION SHOULD
TRANSITION TO ALL RAIN TUESDAY AFTERNOON.

THE STRENGTHENING SURFACE LOW WILL BE POSITIONED OVER THE OKLAHOMA
PANHANDLE LATE TUESDAY AFTERNOON THEN TRACK QUICKLY NORTHEAST ACROSS
SOUTHERN MISSOURI TUESDAY NIGHT AS THE SHORTWAVE EJECTS NORTHEAST
ACROSS THE PLAINS. WARM AIR ADVECTION AHEAD OF THIS SYSTEM SHOULD
KEEP THE PRECIPITATION LIQUID UNTIL THE ASSOCIATED COLD FRONT
SWINGS ACROSS THE OZARKS TUESDAY NIGHT. EXPECT A TRANSITION TO
LIGHT SNOW OR FLURRIES LATE TUESDAY NIGHT...BUT ACCUMULATIONS IF
ANY WILL BE LIGHT. AREAS OF FLURRIES WILL PERSIST INTO WEDNESDAY
MORNING AS STRONG COLD AIR ADVECTION OVERSPREADS THE AREA.

AS WITH ANY DEVELOPING WINTER STORM...THE LATEST WEATHER
INFORMATION SHOULD BE MONITORED AS EVEN SLIGHT CHANGES IN THE
TRACK OF THE STORM COULD BRING MORE WINTER WEATHER INTO THE AREA.

THE UPPER PATTERN WILL GRADUALLY DEAMPLIFY LATE IN THE WEEK WITH MODEST
WARMING EXPECTED. SOME CHANCE EXISTS FOR LIGHT WINTER PRECIPITATION
ON FRIDAY AS A SOUTHERN STREAM SYSTEM TRACKS WELL TO OUR SOUTH. OTHERWISE
RATHER TRANQUIL AND SEASONABLY COLD WEATHER IS EXPECTED FROM LATE
WEEK INTO THE WEEKEND.

FOSTER

&&

.AVIATION...

FOR THE 06Z TAF PACKAGE...PRIMARY FORECAST CONCERNS REVOLVE AROUND
EXPANSIVE STRATUS DECK AND OUTSIDE SHOT AT PATCHY FREEZING
DRIZZLE. MEASURABLE PRECIP IS NOW WELL TO THE EAST OF THE
AERODROMES...THOUGH RADAR CONTINUES TO PICK UP LIGHT RETURNS
CONSISTENT WITH DZ. TEMPERATURES WILL SLOWLY FALL BELOW FREEZING
OVERNIGHT AFTER THE FRONT PASSES THROUGH THE AREA. CIGS WILL
REMAIN IFR AT SGF FOR THE DURATION...WITH IFR PREFRONTAL AT BBG
LIFTING POST FRONTAL AS NORTHWEST FLOW SPREADS OVER THE AREA. MVFR
CIGS WILL BE COMMON AT JLN WITH ONLY VIS RESTRICTS ASSOCIATED WITH
DZ AT ALL SITES. GRADUAL LIFTING OF CIGS ON TAP ON MONDAY...BUT
THIS WILL TAKE TIME. MVFR IS EXPECTED MOST OF THE DAY...WITH
IMPROVEMENT NOT EXPECTED UNTIL THE AFTERNOON HOURS.

GAGAN

&&

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

$$