000
FXUS63 KLSX 161736
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1236 PM CDT TUE MAR 16 2010
.DISCUSSION...
/326 AM CDT TUE MAR 16 2010/
LARGE MASS OF STRATUS ADVECTING SEWD THRU NERN MO W CNTRL IL EARLY
THIS MRNG...WHILE STRATOCUMULUS DECK WAS ADVECTING SWWD THRU MUCH OF
THE SERN PORTION OF THE CWA. LOOKS LIKE THE STRATUS CLOUDS WILL
PUSH SEWD INTO MUCH OF THE CWA BY MID-LATE MRNG. THIS LOW LEVEL CLOUD
DECK SHOULD SLOWLY RISE AND BECOME MORE CUMULIFORM THIS AFTN WITH
BREAKS. WILL GO WITH A MOSTLY CLOUDY FORECAST FOR MUCH OF THE CWA
TDA. MODELS DO NOT SEEM TO HAVE A GOOD HANDLE ON THIS STRATUS
CLOUD COVER AND MAY HAVE TO LOWER THE HIGH TEMPERATURE FORECAST
TDA BELOW THE MOS GUIDANCE. THE MODELS ARE FORECASTING A MID-UPPER
LEVEL LOW TO DROP SWD THRU ERN KS WRN MO TGT AND WED MRNG. THERE
WILL BE LIMITED MOISTURE WITH THIS FEATURE AND LITTLE IF ANY
SFC/LOW LEVEL REFLECTION. IT APPEARS THAT THERE WILL BE SOME LIGHT
RAIN AHEAD OF THE MID-UPPER LEVEL LOW MAINLY ACROSS WRN MO. WILL
INCLUDE LOW POPS MAINLY OVER CNTRL MO TGT...MOST AREAS OF THE CWA
SHOULD NOT GET MORE THAN NON MEASUREABLE SPRINKLES. SHOULD FINALLY
GET WIDESPREAD CLEARING BEHIND THIS MID-UPPER LEVEL SYSTEM FOR
WED NGT AND THU WHICH WILL ALLOW FOR A LARGER DIURNAL SWING IN
TEMPERATURES. NIGHTIME LOWS WILL BE CLOSER TO SEASONAL NORMALS WED
NGT AND THU NGT...WHILE DAYTIME HIGHS SHOULD BE ABOVE NORMAL WITH
HIGHS BOTH THU AND FRI IN THE 60S OVER MOST OF THE CWA. THE NEXT
WEATHER SYSTEM WILL BRING RAIN INTO THE NWRN PORTION OF THE CWA
FRI NIGHT AS A CDFNT SAGS SEWD INTO THE CWA. IT APPEARS THAT MOST
OF THE QPF WILL BE POST FRONTAL. MORE SIGNIFICANT PRECIPITATION IS
EXPECTED ON SAT AND SAT NGT AS AN UPPER LEVEL LOW AND ASSOCIATED
SFC LOW MOVE NEWD THRU THE REGION. STILL A LOT OF UNCERTAINTY WITH
THE TRACK OF THE UPPER/SFC LOW BUT IT COULD BRING A SIGNIFICANT
AMOUNT OF SNOW TO THE NWRN PORTION OF THE CWA AND RAIN TO THE SERN
PORTION. THE LATEST GFS MODEL IS A LITTLE FASTER AND FURTHER N
WITH THE SFC LOW COMPARED TO THE ECMWF.
GKS
&&
.AVIATION...
/1224 PM CDT TUE MAR 16 2010/
AREA OF LIFR CIGS OVER CNTL MO NEWD INTO WRN IL WILL REMAIN LOCKED
IN PLACE THROUGH THE AFTERNOON. MAIN QUESTION WILL BE IF CIGS WILL
LIFT TO IFR BRIEFLY THIS AFTERNOON BEFORE LOWERING AGAIN THIS EVE.
HAVE KEPT TAF DRY FOR NOW AS CHANCES OF PRECIP ARE LOW. GIVEN THE
WEAK FORCING...POTENTIAL EXISTS FOR AREAS OF DZ. IF DZ DOES
OCCUR...VISBYS WILL DROP LOWER THAN CURRENTLY FORECAST. EXPECT
VISBYS AND CIGS TO SLOWLY LIFT WED MORNING INTO THE AFTERNOON HOURS.
FOR SUS...PLEASE SEE DISCUSSION BELOW FOR STL.
SPECIFICS FOR KSTL...TERMINAL REMAIN ON THE EDGE OF HIGH MVFR/LOW
VFR CIGS AND AND AREA TO THE W AND N OF IFR CIGS. LATEST SAT
IMAGES SHOW THE AREA OF IFR SLOWLY MOVING S TOWARD THE TERMINAL.
BELIEVE INSOLATION WILL BE STRONG ENUF TO HELP ERODE THIS CLOUD
DECK AND IT WILL RETREAT SOMEWHAT NWD. STILL...AS INSOLATION IS
LOST THIS EVE...THIS AREA OF CLOUDS SHUD BEGIN TO DRIFT SWD AND
IMPACT STL OVERNIGHT. SOME MVFR TO POSS IFR VISBYS MAY ALSO
ACCOMPANY THESE IFR CIGS BUT HAVE LEFT OUT FOR NOW. CIGS SHUD LIFT
WED LATE MORNING OR INTO THE EARLY AFTERNOON.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
