Hail in Missouri, March 2, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
239 AM CST FRI MAR 2 2012

.SHORT TERM...
ISSUED AT 233 AM CST FRI MAR 2 2012
(TODAY)

PRIMARY CONCERN FOR TODAY IS TSRA CHCS AND POTENTIAL FOR SVR WX WITH
ELEVATED TSRA THAT HAVE DVLPD EARLY THIS MORNING OVER SWRN MO AS A
STRONG LLJ RIDES OVER A SFC WMFNT THAT WAS LOCATED JUST SOUTH OF THE
MO/AR BORDER. CONDITIONS WILL BECOME INCREASINGLY FAVORABLE FOR
CONVECTION THIS MORNING GIVEN LEFT EXIT REGION DYNAMICS OF A STRONG
H25 JET...INCREASING H5-H7 LAPSE RATES...LARGE SCALE ASCENT WITH THE
APPROACH OF AN UPPER LEVEL TROUGH...AND PLENTY OF SHEAR. THE PRIMARY
THREAT THIS MORNING IS LARGE HAIL WITHIN THE ELEVATED THUNDERSTORMS.
PCPN IS EXPECTED TO SIMULTANEOUSLY EXPAND EWD AND LIFT NWD WITH TIME
THROUGH THE MORNING. NEXT CONCERN IS FOR TSRA ACROSS THE ERN HALF OF
THE CWA AHEAD OF THE CDFNT LATER THIS MORNING AND INTO THE AFTN WITH
QUALITY MOISTURE SPREADING NWD AHEAD OF THE FNT. TSRA THREAT ENDS
FROM WEST TO EAST BEHIND THE CDFNT. THERE MAY BE SOME SNOW MIXED
WITH RAIN IN THE NRN CWA LATE THIS AFTN HOWEVER LITTLE TO NO
ACCUMULATION IS EXPECTED.

KANOFSKY
&&

.LONG TERM...
ISSUED AT 233 AM CST FRI MAR 2 2012
(TONIGHT-THURSDAY)

WITH THE RAPID MOVEMENT OF TODAYS SYSTEM PRECIP SHOULD THREAT
SHOULD BE EXITING OUR FAR E COUNTIES NO LATER THAN 00Z...WITH
COOLER AND DRIER WEATHER IN THE OFFING OVERNIGHT AND INTO
SATURDAY. THERE IS A FAIRLY LARGE DISCREPENCY IN MOS TEMPS FOR
SATURDAY SO HAVE MODELED TEMP FORECASTS BASED ON CONSENSUS 850
TEMP PROGS...WHICH ENDS UP SPLITTING THE DIFFERENCE BETWEEN THE
MET AND MAV.

SHORTWAVE IS STILL PROGGED TO ZIP ACROSS THE AREA DURING THE DAY ON
SUNDAY...ALTHOUGH TIMING AND EXACT LOCATION OF FEATURES CERTAINLY
VARIES BETWEEN THE MODELS.  I'VE TRIED TO INCREASE THE TEMP GRADIENT
ACROSS THE AREA BY UPPING TEMPS OVER MID MO...AS MODERATE W
COMPONENT TO LOW LEVEL FLOW SHOULD ALLOW FOR DECENT WARMING IN THIS
AREA. GIVEN LARGE MODEL SPREAD WITH REGARDS TO BEST
FORCING/LIFT/MOISTURE HAVE CONTINUED TO LIMIT MENTION OF PRECIP TO
SPRINKLES/FLURRIES WORDING FOR NOW.

MODERATING TEMPERATURES SHOULD RETURN TO THE ENTIRE AREA EARLY IN
THE NEW WORK WEEK AS UPPER TROF PUSHES INTO THE EAST COAST AND
ZONAL FLOW RETURNS TO THE CENTRAL CONUS. BY TUESDAY AND
WEDNESDAY...TEMPERATURES SHOULD BE WELL ABOVE AVERAGE.

00Z MEDIUM RANGE SOLUTIONS ARE STILL ADVERTISING STRONG TROF TO PUSH
INTO THE CENTRAL U.S. DURING THE MIDDLE OF NEXT WEEK...WITH THE
GREATEST PRECIP THREAT WITH THIS SYSTEM CENTERED ON THE WED
NIGHT/THU TIME FRAME.

TRUETT

&&

.AVIATION...
ISSUED AT 1057 PM CST THU MAR 1 2012

A WEAK WARM FRONT EXTENDED FROM NEAR COU TO JUST S OF STL THIS
EVNG. SFC WINDS WERE ELY IN UIN AND S-SELY AT THE OTHER TAF SITES.
A SFC LOW OVER OK WILL MOVE NEWD TO SWRN MO AROUND 12Z FRI...THEN TO
JUST NE OF STL BY 18Z FRI AS IT DEEPENS. CONVECTION IS EXPECTED TO
DEVELOP LATE TGT S OF THE TAF SITES AS A SWLY LOW LEVEL JET BRINGS
INCREASING LOW LEVEL MOISTURE NWD INTO OUR AREA. STILL PLENTY OF
UNCERTAINTY WITH THE TIMING AND LOCATION OF THE NOCTURNAL
CONVECTION...BUT IT APPEARS THAT IT WILL MOVE NEWD INTO THE TAF
SITES...EXCEPT UIN...AROUND 11-14Z FRI. UNTIL THEN MAINLY JUST
MID-HIGH LEVEL CLOUDS ARE EXPECTED. MAY INCLUDE LLWS IN THE STL
AREA TAFS DURING THE LATE NGT HOURS AS THE MODELS...ACAR SOUNDINGS
AND LSX VWP SHOWING AT LEAST 40 KTS FROM A SWLY DIRECTION AT 2000
FT IN HEIGHT LATE THIS EVNG. THE CEILINGS WILL LOWER INTO THE MVFR
CATAGORY AS THE SHOWERS AND STORMS MOVE INTO THE TAF SITES IN THE
MRNG. THE SFC WIND WILL BECOME NWLY AS WELL AS STRONG AND GUSTY
AFTER THE PASSAGE OF THE SFC LOW AND TRAILING COLD FRONT.
DEFORMATION ZONE LIGHT PRECIPITATION IS EXPECTED FRI AFTN IN UIN.
THERE MAY BE A MIX OF LIGHT RAIN AND SNOW FROM ABOUT 20Z TO 23Z
FRI IN UIN BEFORE THE PRECIPITATION ENDS AS COLDER AIR FILTERS
INTO THE AREA. THE LOW LEVEL CLOUDS WILL SCATTER OUT BY EARLY FRI
EVNG AS A SFC RIDGE BUILDS SEWD INTO MO.

SPECIFICS FOR KSTL...MAY INCLUDE LLWS IN THE STL TAF UNTIL ABOUT
09Z FRI DUE TO STRONG SWLY WINDS AROUND 2000 FT IN HEIGHT. MID LEVEL
CLOUDS WILL DEVELOP AND MOVE INTO STL LATE TGT WITH AT LEAST
SCATTERED SHOWERS AND STORMS DEVELOPING AND MOVING INTO STL BY
EARLY FRI MRNG. THE CEILING SHOULD DROP INTO THE MVFR CATAGORY FRI
MRNG...THEN RISE INTO THE VFR CATAGORY LATE FRI AFTN...AND SCATTER
OUT FRI EVNG WITH COLDER AND DRIER AIR FILTERING INTO THE REGION
AS A SFC RIDGE BUILDS SEWD INTO THE AREA BEHIND THE SFC LOW AND
TRAILING COLD FRONT. SELY SFC WINDS WILL VEER AROUND TO A SLY
DIRECTION LATE TGT AFTER THE PASSAGE OF A WEAK WARM FRONT...THEN
CONTINUE TO VEER AROUND TO A WLY DIRECTION BY THU AFTN AFTER THE
PASSAGE OF THE SFC LOW AND TRAILING COLD FRONT. THE WIND WILL
BECOME STRONG AND GUSTY THU AFTN DUE TO THE TIGHT SFC PRESSURE
GRADIENT BEHIND THE DEEPENING SFC LOW...THEN WEAKEN FRI EVNG.

GKS

&&

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

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
400 PM CST THU MAR 1 2012

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-021115-
GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL-
MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL-
CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR IL-MONROE IL-KNOX MO-
LEWIS MO-SHELBY MO-MARION MO-MONROE MO-RALLS MO-PIKE MO-BOONE MO-
AUDRAIN MO-MONITEAU MO-COLE MO-OSAGE MO-CALLAWAY MO-MONTGOMERY MO-
LINCOLN MO-GASCONADE MO-WARREN MO-ST. CHARLES MO-FRANKLIN MO-
ST. LOUIS MO-ST. LOUIS CITY MO-JEFFERSON MO-CRAWFORD MO-
WASHINGTON MO-ST. FRANCOIS MO-STE. GENEVIEVE MO-IRON MO-
MADISON MO-REYNOLDS MO-
400 PM CST THU MAR 1 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND
CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS.

.DAY ONE...TONIGHT

THUNDERSTORMS WILL BE POSSIBLE LATE TONIGHT...WITH THE BEST
CHANCES ACROSS SOUTHERN MISSOURI. A FEW OF THESE STORMS MAY BE
SEVERE WITH THE MAIN THREAT BEING LARGE HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE LIKELY FRIDAY. A FEW OF THESE STORMS MAY BE
SEVERE WITH THE MAIN THREAT BEING LARGE HAIL...ESPECIALLY ACROSS
EAST CENTRAL AND SOUTHEASTERN MISSOURI AND SOUTHERN ILLINOIS.

THERE IS ANOTHER CHANCE FOR THUNDERSTORMS WEDNESDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT.

MILLER