FXUS63 KLSX 050857
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
257 AM CST SUN FEB 5 2012

.DISCUSSION...
/255 AM CST SUN FEB 5 2012/

THE SHORT TERM FORECAST OVER THE NEXT 12 HOURS POSES THE BIGGEST
CHALLENGES OVER THE NEXT SEVERAL DAYS. THE FEATURE OF CONCERN IS
THE UPPER LOW FORECAST TO DROP SEWD THROUGH THE AREA TODAY AND THE
ASSOCIATED IMPACTS. PROFILER AND VWP DATA SHOW THAT THE UPPER LOW
HAS PASSED JUST SE OF KANSAS CITY. THE VAST MAJORITY OF PRECIPITATION
THUS FAR HAS ACTUALLY BEEN TO THE NORTH OF THE LOW CENTER...AND
HAS BEEN ROTATING SOUTHWESTWARD ABOUT THE CIRCULATION. NEAR AND
NORTH OF THE LOW ARE THE ONLY LOCATIONS THAT HAVE REPORTED ANY
SNOW THUS FAR AS WELL. CURRENTLY TO THE EAST OF THE LOW ACROSS
EASTERN MO...BANDS OF RAIN SHOWERS HAVE DEVELOPED WITHIN THE LAST
FEW HOURS WITHIN WHAT APPEARS TO BE A REGION OF MID LEVEL QG
FORCING. TEMPERATURES WITHIN THIS AREA RANGE FROM THE UPPER 30S TO
LOWER 40S. THE RUC APPEARS TO HAVE THE BEST HANDLE ON THE TRACK OF
THE UPPER LOW AT THIS TIME...TRACKING IT TO NEAR THE LAKE OF THE
OZARKS REGION BY 18Z. THEREAFTER THE MAJORITY OF THE MODELS WOULD
SUGGEST IT WILL CONTINUE TO TRACK SEWD AND INTO SE MO THIS
AFTERNOON AND THEN EXIT INTO THE WESTERN TN VALLEY TONIGHT. BASED
ON THIS LOW TRACK AND THE ASSOCIATED QG FORCING TO THE EAST...EXPECTING
CHANCE POPS/SCATTERED SHOWERS/DRIZZLE TO IMPACT THE AREA FROM
COU-STL-SLO SOUTHWARD. I AM NOT VERY EXCITED ABOUT THE PROSPECTS
OF ANY SNOW AND GIVEN ONLY SLIGHTLY COOLER TEMPERATURES EARLY THIS
MORNING THAN NOW...I WOULDN'T EXPECT ANY ACCUMULATION IF WE DID
SEE SOME. BY THIS AFTERNOON THE POP THREAT SHOULD BE CONFINED TO
FAR SE MO. STRATUS WILL SLOWLY CLEAR SOUTH THROUGH THE DAY AS
WELL.

WEAK HIGH PRESSURE WILL DOMINATE THE REGION TONIGHT WITH
SEASONABLY CHILLY TEMPERATURES. WESTERLY LOW LEVEL FLOW AND WARM
ADVECTION THEN GETS GOING ON MONDAY AND TEMPERATURES WILL ONCE
AGAIN BE ABOVE AVERAGE. THE NEXT SHOT OF COLD AIR LOOKS ON TRACK
FOR TUESDAY AS A NORTHERN STREAM SHORT WAVE TROF DIGS SOUTHEAST
INTO THE UPPER MIDWEST AND INTERACTS WITH THE REMNANT GREAT BASIN
UPPER LOW. WE CURRENTLY HAVE POPS JUST BELOW THRESHOLDS THAT ARE
MENTIONED IN THE FORECAST FOR THIS SYSTEM. THERE IS AND HAS BEEN
QUITE A BIT OF VARIABILITY WITH THE PRECIPITATION CHANCES...AND
CONFIDENCE IS LOW AT THIS TIME. ANYWAY THIS SHOT OF COLD AIR WILL BE A
GLANCING SHORT-LIVED BLOW BRINGING TEMPERATURES BACK DOWN TO
SEASONABLE NORMS TUESDAY NIGHT-WED NIGHT.

THE LONGER RANGE GUIDANCE...WHILE SHOWING SOME DETAIL DIFFERENCES
...IS TRENDING TOWARDS TEMPERATURES MORE WINTER-LIKE BY THE END
OF THE UPCOMING WEEK. THE GENERAL IDEA AT THIS JUNCTURE IS A DEEP
VORTEX WILL BECOME ESTABLISHED NEAR HUDSON BAY WITH A DEEP FULL
LATITUDE TROF EXTENDING TO THE SOUTH INTO THE EASTERN U.S.. THE
ORIENTATION OF THIS TROF AND INTENSITY/LONGEVITY OF THE COLD AIR
ARE WHERE THE MODELS DIFFER WITH THE GFS SHOWING POTENTIAL FOR
SOME OF THE COLDEST AIR THIS SEASON.

GLASS

&&

.AVIATION...
/1125 PM CST SAT FEB 4 2012/

MAIN FOCUS WILL BE CIGS/VSBYS. REMOVED MENTION OF SN AT COU AS ANY
PRECIP SHUD REMAIN LIQUID WITH SN REMAINING FURTHER W. BELIEVE DZ
WILL PERSIST THRU MUCH OF THE NIGHT. CONDITIONS AT UIN SHUD BEGIN
TO IMPROVE AS DRIER AIR ADVECTS INTO THE AREA. WITH DZ COMING TO
AN END AT SUS/CPS...VSBYS SHUD IMPROVE OVERNIGHT...THO PATCHES OF
DZ MAY DEVELOP AGAIN LATER TONIGHT.

SPECIFICS FOR KSTL...VSBYS SHUD IMPROVE AS DZ HAS COME TO AN
END...THO CAN NOT RULE OUT REDEVELOPMENT BEFORE SUNRISE. CIGS SHUD
IMPROVE MID TO LATE SUNDAY MORNING. WINDS EXPECTED TO REMAIN NELY
TO NLY THRU PERIOD AND DIMINISH SUNDAY AFTERNOON AS THE SFC RIDGE
BUILDS IN. CONDITIONS SHUD BE FAVORABLE FOR FG DEVELOPMENT SUN
NIGHT. HOWEVER...CONFIDENCE THIS FAR OUT IS TOO LOW TO MENTION IN
TAF ATTM.

TILLY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX



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