000 
FXUS63 KLSX 252355
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
555 PM CST MON FEB 25 2008

.DISCUSSION...
OBVIOUSLY...MAIN CONCERN FOR THE SHORT TERM IS UPCOMING WX TRENDS
FOR TNGT AND TUE. AS WAS FEARED YSTDA...EACH SUCCESSIVE MODEL RUN
CONTS TO TREND A BIT FURTHER S WITH THE LOW...WHICH IS CURRENTLY
JUST EAST OF MKC. AS THE LOW TRACKS JUST S OF STL THIS EVENING
LARGE BAND OF PCPN OCRG N OF THE LOW FROM SE NE INTO S IA WL ALSO
DROP SE...WITH ADDITIONAL DVLPMT OCRG OVR THE AREA AS INITIALLY
DRY LO LVLS IS FCST TO SATURATE QUICKLY. AS FAR AS THE CHGOVR TO
SNOW IS CONCERNED...OUR THINKING IS THAT SNW WL BGN ERH THIS
EVENING ARND UIN...ABT MIDN NR COU...WITH A RPD CHGOVR OCRG FROM
STL AND SE IN THE 09Z-12Z TIME FRAME.  

ONCE THE CHGOVR TO SNOW OCCCURS..CONSENSUS QPF FROM MODELS SUGGESTS
THAT ACCUM IN THE 1-3 INCH RANGE CAN BE EXPECTED THRU MIDDAY TUE
ALG AND E OF A MEXICO...WARRENTON...NASHVILLE IL LN...WITH THE
HIGHEST ACCUMULATIONS OVR CNTRL IL SECTION OF OUR FA. STG NW WNDS
GUSTING TO ARND 40 MPH WL BE CAUSING BLOWING AND DRIFTING...AND
THINK THAT ONCE THE CHGOVR TO SNOW OCRS CONDS WL DETERIORATE
QUICKLY. HV OPTED TO ISSUE A SNOW AND BLOWING SNOW ADVISORY FOR
THE ABV AREAS DUE TO THIS THRT...WITH THE ONSET OF THE ADVSRY TIED
TO THE START TIMES OF THE SNOW AS GIVEN IN THE FIRST PARAGRAPH OF
THE AFD.

CERTAINLY...THE SGFNT PCPN WL BE WINDING DOWN TMRW AFTN...WITH
WNDS SLOWLY SUBSIDING DURG THE LT AFTN AND EVENING HRS AS SFC RDG
PUSHES E AND GRADIENT OVR REGION BGNS TO RELAX. 

TEMPS WL BGN DROPPING TNGT IN THE WAKE OF THE SFC LOW...AND SHUD
CONTINUE THEIR DROP MOST OF THE DAY TUE AND INTO TUE NGT.

FOR THE REMAINDER OF THIS FCST PKG...WED-SUN...GOING TRENDS WL
GENLY REMAIN UNCHGD AS MODEL SOLNS CONT TO SHOW GOOD RUN TO RUN
CONSISTENCY. HV KEPT MAX TEMPS TWD THE LO SIDE OF GUIDANCE ON
WED...WITH TEMPS TRENDING TO NR OR SLGLTLY ABV NORMAL THU-SUN. A THRT
OF PCPN WL CONT THU NGT AND FRI WITH NXT SYS...BUT WITH MOST OF
THE DYNAMICS RMNG WELL N OF AREA THINK POPS WL BE LO. AND COOLING
BHND SYSTEM JUST CLIPPING AREA NO BIG CHG IS TEMPS IS EXPECTED
WITH PASSAGE OF FNT. STGR SYSTEM DOES APR IN THE OFFING BY
MONDAY...WITH A DROP IN TEMPS AT THAT TIME.

TRUETT

&&

.AVIATION...
FOR THE 00Z TAFS...
A WHOLE HOST OF PROBLEMS FOR AVIATION INTERESTS TONIGHT. SYSTEM
MOVING FROM GREAT PLAINS THROUGH THE MID-MISSISSIPPI VALLEY
TONIGHT WILL SPREAD IFR/LIFR CIGS ACROSS THE AREA TONIGHT...WITH
POSSIBLE SNOW AND BLOWING SNOW ON THE NORTHWEST/WEST SIDE OF THE
LOW. WINDS SHOULD INCREASE TO 20-30KTS...PERHAPS WITH EVEN HIGHER
GUSTS OVERNIGHT TONIGHT AS THE SYSTEM MOVES INTO THE TENNESSEE
VALLEY. THERE IS SOME QUESTION AS TO HOW MUCH SNOW WILL
FALL TONIGHT. LATEST GUIDANCE ISNT AS ROBUST WITH THE SNOWFALL AS
PREVIOUS RUNS...BUT NOT QUITE READY TO MAKE WHOLESALE CHANGES TO
THE FORECAST BASED ON ONE RUN OF THE MODELS. WILL CONTINUE TO
MONITOR AND REEVALUATE AS NECESSARY AS THE SYSTEM EVOLVES THIS
EVENING.

CARNEY

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM 
     CST TUESDAY FOR AUDRAIN-LINCOLN-MONROE-MONTGOMERY-PIKE-
     RALLS.

     SNOW AND BLOWING SNOW ADVISORY FROM 3 AM TO 12 PM CST TUESDAY 
     FOR FRANKLIN-JEFFERSON-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-
     WARREN.

     SNOW AND BLOWING SNOW ADVISORY FROM 9 PM THIS EVENING TO 12 PM 
     CST TUESDAY FOR KNOX-LEWIS-MARION-SHELBY.

IL...SNOW AND BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM 
     CST TUESDAY FOR PIKE IL.

     SNOW AND BLOWING SNOW ADVISORY FROM 3 AM TO 12 PM CST TUESDAY 
     FOR BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-
     JERSEY IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-
     MONTGOMERY IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.

     SNOW AND BLOWING SNOW ADVISORY FROM 9 PM THIS EVENING TO 12 PM 
     CST TUESDAY FOR ADAMS IL-BROWN IL.

&&

$$

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