FXUS63 KLSX 090554
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1154 PM CST WED FEB 8 2012

.DISCUSSION...
/229 PM CST WED FEB 8 2012/

WITH LITTLE IF ANY PRECIP ANTICIPATED THRU THE SHORT TERM...FOCUS
TURNS TO TEMPS.

SFC RIDGE WILL BUILD INTO THE REGION TONIGHT INTO THURS. A WEAK S/W
WILL DROP S TONIGHT TO HELP SPREAD ENUF CLOUD OVER THE AREA TO
SUPPRESS FG THREAT. HOWEVER...GIVEN THE RECENT SN AND MELTING THRU
THE DAY...CAN NOT RULE OUT SOME FG OVERNIGHT WITH A VERY MOIST
BOUNDARY LAYER.

SLY FLOW EXPECTED TO RETURN TO THE AREA THURS MORNING. HAVE
THEREFORE TRENDED TWD WARMER GUIDANCE THRU TOMORROW NIGHT. THIS WARM
TREND WILL BE SHORT LIVED AS A CDFNT IS PROGD TO MOVE THRU THE CWA
FRI MORNING AND EARLY AFTERNOON. HAVE TRENDED TWD COOLER MOS FOR THE
NRN HALF OF THE CWA ON FRI AND CONSENSUS ELSEWHERE. MDLS AGREE WELL
WITH TIMING OF FROPA...BUT SHUD STILL SEE SOME HEATING BEHIND THE
FNT WITH CLEAR SKIES. WITH A VERY LARGE SFC RIDGE BUILDING INTO THE
REGION BEHIND THIS FNT...HAVE TRENDED AOB THE COOLEST GUIDANCE FOR
THE REMAINDER OF THE SHORT TERM AND CONTINUE INTO THE EXTD PERIOD.

FOR PRECIP...HAVE ADDED SLIGHT CHANCE POPS FOR THE FAR SRN TIER OF
THE CWA AS A SRN STREAM S/W PULLS MOISTURE NWD AHEAD OF THE CDFNT.
GIVEN THE TIMING OF THE FNT...BELIEVE ANY PRECIP WILL REMAIN S OF
THE CWA. STILL...ADDED THE SLIGHT CHANCE IF FNT IS SLOWER THAN
ADVERTISED.

FOR THE EXTD...COOL TREND CONTINUES INTO SUN...THO WITH SOME
DIFFERENCES IN MDL GUIDANCE...GOING FCST MAY STILL BE A COUPLE OF
DEGREES TOO WARM. WARM UP SHUD BEGIN MON AS THE SFC RIDGE MOVES OFF
TO THE E. THE MAIN QUESTION WILL BE HOW MUCH WARMER.

MDLS ARE IN GOOD AGREEMENT WITH DEEPENING TROF WITH A LEADING S/W
SPREADING PRECIP OVER THE AREA ON MON INTO MON NIGHT. HOWEVER...MDLS
DISAGREE REGARDING P TYPE. THE ECMWF/GEM SOLNS ARE COLDER ALOFT AND
SUGGEST SN. THE GFS KEEPS H85 TEMPS ABOVE FREEZING ACROSS MUCH OF
THE AREA...WITH SFC TEMPS HOVERING AT OR JUST ABOVE FREEZING. GIVEN
THE VERY COLD AIR THAT SHUD BE IN PLACE...BELIEVE THE MDLS ARE
MOVING THE SFC RIDGE OUT TOO FAST. FOR NOW...HAVE A MIX OF RA/SN
GOING IN THE FCST AND WILL ADJUST AS MDLS COME INTO AGREEMENT.

BEYOND MON...TEMPS CONTINUE TO WARM AHEAD OF THE NEXT SYSTEM. THE
12Z GFS AND 00Z ECMWF WERE IN GOOD AGREEMENT...BUT THE 12Z ECMWF IS
ABOUT 24 HRS SLOWER WITH THIS SYSTEM. HAVE LOW CHANCE POPS FOR THIS
EVENT UNTIL MDLS COME INTO AGREEMENT.


TILLY

&&

.AVIATION...
/1136 PM CST WED FEB 8 2012/
CLOUDS AND FOG POTENTIAL WILL BE THE FOCUS FOR THIS PACKAGE.
MODELS CONTINUE TO PERFORM POORLY WITH THE LOW LEVEL RH FIELDS.
LOW LEVEL MOISTURE REMAINS TRAPPED UNDER SFC RIDGE. THERE HAVE
BEEN A FEW BREAKS IN THE OVC REPORTED AROUND THE STL METRO
AREA DURING THE PAST COUPLE OF HOURS...BUT EXPECT THESE TO BE
TRANSIENT AND BRIEF. CLOUDS HAVE BEEN SLOW TO CLEAR THIS
EVENING...BUT SHOULD AT LEAST TEMPORARILY SCATTER OUT AT KCOU OVER
THE NEXT HOUR OR SO. THIS SHOULD BE SHORT LIVED AS ANOTHER AREA OF
3-4 KFT CIGS IS POISED TO MOVE EAST OVER THE TERMINAL BY 7Z-8Z PER
SATELLITE. MVFR FOG IS STILL POSSIBLE TOWARDS SUNRISE...ESP AT KUIN
WHERE IT HAS BEEN CLEAR FOR A COUPLE HOURS AND SHOULD REMAIN SO
FOR THE REST OF THE NIGHT. THE NEXT BATCH OF VFR CIGS IS IN ASSOC
WITH AN UPSTREAM SHORT WAVE THAT WILL TRAVERSE THE AREA ON
THURSDAY. THIS WILL BRING IN BKN/OVC CIGS NEAR 4 KFT DURING THE
LATE MORNING TO EARLY AFTN. THE CIGS SHOULD THEN STICK AROUND THRU
THE REMAINDER OF THE FCST PERIOD. HAVE A MORE PESSIMISTIC FCST
THAN WHAT MODELS INDICATE BASED ON CURRENT SLOW CLEARING TRENDS
AND RECENT POOR MODEL PERFORMANCE.

SPECIFICS FOR KSTL...
VFR CLOUDS AND POSSIBLE CLEARING TRENDS REMAIN THE MAIN FOCUS FOR
THIS FCST PERIOD. A FEW BREAKS HAVE BEEN REPORTED THIS
EVENING...BUT EXPECT THEM TO BE TRANSIENT AND BRIEF IN NATURE.
THERE IS ANOTHER CHANCE AROUND 15Z THAT THE CIGS MAY BRIEFLY
SCATTER OUT AS THE CLEARING IN NORTHERN MO WORKS SE. THIS WILL BE
QUICK IF AT ALL AS THE NEXT BATCH OF VFR CIGS INVADES FROM THE WEST
IN ASSOC WITH AN UPSTREAM SHORT WAVE. NOT CONFIDENT ENOUGH THAT
THIS WILL OCCUR TO INCLUDE IN THE FCST ATTM. THERE IS ANOTHER
CHANCE LATE IN THE PERIOD IN ADVANCE OF A STRONG COLD FRONT BEFORE
MORE LOWER CIGS MOVE IN BEHIND THE FRONT. DUE TO THE LOW POTENTIAL
SO LATE IN THE FCST PERIOD...THERE IS NO REASON TO ADD A NEW FROM
GROUP.

MILLER

&&

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

$$

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