Severe Thunderstorm Warning 79, NWS St. Louis, MO

970 
WWUS53 KLSX 260301
SVSLSX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1001 PM CDT TUE MAY 25 2010

MOC071-260311-
/O.CAN.KLSX.SV.W.0079.000000T0000Z-100526T0315Z/
FRANKLIN MO-
1001 PM CDT TUE MAY 25 2010

...THE SEVERE THUNDERSTORM WARNING FOR FRANKLIN COUNTY IS
CANCELLED...

THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER POSES AN IMMEDIATE THREAT TO LIFE OR PROPERTY.
HOWEVER GUSTY WINDS AND HEAVY RAIN ARE STILL POSSIBLE WITH THIS 
THUNDERSTORM.

LAT...LON 3859 9116 3844 9091 3820 9119 3820 9124
      3828 9138 3832 9137
TIME...MOT...LOC 0301Z 217DEG 11KT 3840 9115

$$

CARNEY

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
905 PM CDT TUE MAY 25 2010

.UPDATE...
/852 PM CDT TUE MAY 25 2010/
UPDATED FORECAST THIS EVENING TO CUT POPS ACROSS THE EASTERN 1/2
OF THE CWA. LOOKS LIKE MID/UPPER LEVEL RIDGING ALONG AND EAST OF
THE MISSISSIPPI IS KEEPING CONVECTION IN CHECK TONIGHT. BACK OVER
CENTRAL AND NORTHEAST MO...ISOLATED TO WIDELY SCATTERED STORMS
WILL LIKELY CONTINUE THROUGH AT LEAST MUCH OF THE EVENING AND
PERHAPS THROUGH THE OVERNIGHT AS WELL. RUC IS SHOWING 1500-2000
CAPE OVER THE AREA ATTM. THE INSTABILITY DOES WEAKEN AFTER
MIDNIGHT...BUT CAPES STILL RUN HIGHER THAN 1000 J/KG. RUC ALSO
SHOWING SOME WEAK MOISTURE CONVERGENCE AT 850MB WHICH IT MAINTAINS
UNTIL AFTER 06Z...SO THINK ISO/SLIGHT CHANCE IS STILL WARRANTED
AFTER MIDNIGHT.

CARNEY

&&

.DISCUSSION...
/350 PM CDT TUE MAY 25 2010/

VERY LITTLE CINH IN PLACE OVER THE FA ATTM...AND ALL IT REALLY
NEEDS IS A FOCUS...EITHER IN THE FORM OF AN OUTFLOW BOUNDARY OR
AN UPPER LEVEL VORT BOTH OF WHICH ARE PRESENT. WEAK VORT SITS OVER
THE STL METRO AREA...WHILE OUTFLOW BOUNDARIES ARE ENTERING INTO
W CNTRL IL AND CNTRL/SERN MO. LOOK FOR SOME TSRA DEVELOPMENT TO
TAKE PLACE NEAR THESE FOCUSES OVER THE NEXT FEW HRS...WITH WHAT
DOES DEVELOP CONTINUING THRU MUCH OF THE EVENING.

HUMID AND UNSTABLE AIRMASS TO REMAIN IN PLACE AT LEAST UNTIL
WEDNESDAY...WHEN A COLD FRONT WILL SLOWLY PUSH THRU THE AREA...
TAKING UNTIL THURSDAY TO COMPLETELY MOVE THRU. THIS WILL MAINTAIN
PCPN CHCS FOR AT LEAST AIRMASS TYPE TSRA...BUT BEGINNING
WEDNESDAY...WE WILL ALSO HAVE A MORE PROMINENT FOCUS IN THE FORM
OF THE CDFNT. A MODERATELY STRONG UPR LVL VORT WILL ALSO DRIVE
THRU THE AREA ON THURSDAY...ADDING AN ADDITIONAL FOCUS FOR TSRA
DEVELOPMENT. HIGHEST POPS GEARED TOWARDS THESE FOCUSES.

MOS TEMPS IN THE BALLPARK OF WHAT WE EXPECT...AND GENERALLY USED
ALTHOUGH PREFERRED THE WARMER...ON AVERAGE...MAV OUTPUT OVER THE
MET.

BONE DRY AIRMASS AND COOLER AIR MOVES IN BY FRIDAY...AND SIGNALS
THE BEGINNINGS OF WHAT APPEARS TO BE A SEASONABLY WARM AND DRY
HOLIDAY WEEKEND...OR AT LEAST FOR MOST OF IT...WITH FEW CLOUDS.

FOR THE EXTENDED PERIOD (FRIDAY NIGHT - TUESDAY)...MODELS ARE IN
GOOD AGREEMENT THAT THE PERSISTENT H500 RIDGE BLOCKING PATTERN
WILL GRADUALLY BREAK DOWN DURING THIS TIME...BUT DIFFER ON HOW
FAST TO ACCOMPLISH IT. 00Z/06Z GFS WAS PART OF ONE CAMP THAT
FAVORED A QUICKER BREAKING DOWN OF THIS RIDGE...BUT THE 12Z HAS
SINCE SWITCHED TO THE SLOWER CAMP OF WHICH BELONGED THE BETTER
MEDIUM RANGE VERIFYING ECMWF. THIS SEEMS MORE BELIEVABLE...AND
SHOULD YIELD QUIET WX FOR MUCH OF THE HOLIDAY WEEKEND UNTIL
PERHAPS THE VERY END ON MEMORIAL DAY. MODELS IN DECENT AGREEMENT
THAT BY MEMORIAL DAY... PATTERN SHOULD HAVE BROKEN DOWN ENOUGH TO
RESULT IN ZONAL FLOW BY LATE ON MEMORIAL DAY AND WITH THIS...THE
INCREASE OF PCPN CHCS. IN FACT...THE COMBO OF ZONAL FLOW ALOFT
WITH HINTS AT UPPER LEVEL DISTURBANCES TRACKING THRU THE AREA AND
THE PRESENCE OF A WEAK BDRY AT THE SFC SHOULD BE CONDUCIVE TO MCS
DEVELOPMENT BY EARLY-MID NEXT WEEK. IT WILL JUST BE A MATTER OF
EXACTLY WHEN AND WHERE IT WILL TRACK. SKILL IS NOT THAT GREAT ON
MCS THAT FAR OUT...ESPECIALLY WITH ONLY WEAK SIGNALS TO GO ON...SO
HAVE ONLY PLACED SLIGHT CHC PLACEHOLDERS IN THERE FOR MONDAY AND
TUESDAY FOR NOW. TEMPS WILL BEGIN THE PERIOD AT OR A LITTLE BIT
ABOVE NORMAL...BUT SHOULD LOSE A FEW DEGS BY THE END OF THE
PERIOD...ESPECIALLY IF THE WEAK BDRY PUSHES INTO SRN MO AND IL.

TES

&&

.AVIATION...
/558 PM CDT TUE MAY 25 2010/

BROAD AREA OF SFC HI PRES CONTINUES ACRS MO SEEMINGLY LIMITING
CONVECTION OVER TERMINALS. INSTABILITY AND MOISTURE EVER-PRESENT
WITH INHIBITION NON-EXISTANT. PER LATEST SATELLITE-RADAR TRENDS IT
IS PERHAPS SUBSIDENCE THAT IS THE CULPRIT. WILL FOLLOW WITH VCTS
FOR KCOU-KUIN AND MONITOR INTO EVNG. CONVECTION TO DISSIPATE WITH LGT
AND VRB WINDS OVERNIGHT...VSBYS MAY REDUCE INTO MRNG FOR KUIN BUT
DO NOT BELIEVE TO MVFR. TSRA ANTICIPATED TO DEVELOP INTO MIDDAY AS
A WEAK FRONTAL DISTUBANCE EDGES EWD INTO THE BI-STATE RGN. ALTHOUGH
TSRA APPEARS MORE LIKELY SPECIFICS ARE UNCERTAIN...HAVE VCTS FOR
TOMORROW AFTN AND EVNG.

SPECIFICS FOR KSTL...CONVECTION APPEARS LIMITED BUT WILL MONITOR
CLOSELY...HAVE THUS REMOVED VCTS WORDING. CU SHOULD DISSIPATE
OVERNIGHT WITH LGT AND VRB WINDS. INTO TOMORROW A WEAK FRONTAL
DISTURBANCE IS ANTICIPATED EDGE INTO THE RGN. TSRA IS MORE LIKELY
BY MIDDAY INTO EVNG...YET UNCERTAIN IN TIMING AND IMPACT SPECIFICS...
HAVE MENTIONED VCTS FOR NOW.

SIPPRELL

&&

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

WFO LSX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ST LOUIS MO
335 PM CDT TUE MAY 25 2010

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-261200-
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-
335 PM CDT TUE MAY 25 2010

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

.DAY ONE...TONIGHT

THERE IS A CHANCE FOR THUNDERSTORMS...MAINLY THIS EVENING WHEN
THE ATMOSPHERE WILL BE THE MOST UNSTABLE. ALTHOUGH ORGANIZED AND
WIDESPREAD SEVERE WEATHER IS NOT EXPECTED A FEW STORMS MAY BECOME
STRONG TO SEVERE PRODUCING HAIL AND STRONG WIND GUSTS. SINCE THE
STORMS WILL BE SLOW MOVING A FEW OF THEM COULD ALSO PRODUCE
LOCALIZED FLOODING.

MODERATE FLOODING IS OCCURRING AT CHESTER ALONG THE MISSISSIPPI
RIVER.  PLEASE SEE THE APPROPRIATE FLOOD STATEMENT FOR SPECIFIC
DETAILS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE CHANCE FOR THUNDERSTORMS WILL CONTINUE THROUGH THURSDAY
EVENING.

MODERATE FLOODING IS EXPECTED TO CONTINUE AT CHESTER ALONG THE
MISSISSIPPI RIVER UNTIL SATURDAY MORNING. PLEASE SEE THE
APPROPRIATE FLOOD STATEMENT FOR SPECIFIC DETAILS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS EVENING...MAINLY IN PORTIONS
OF CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL
ILLINOIS.

&&

FOR A GRAPHICAL VERSION OF THIS INFORMATION SEE OUR
WEBPAGE AT (LOWERCASE)... HTTP://WWW.WEATHER.GOV/LSX/?N=HWO1

TES

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
924 PM CDT TUE MAY 25 2010

MOZ062-260315-
FRANKLIN MO-
924 PM CDT TUE MAY 25 2010

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN FRANKLIN COUNTY UNTIL
1015 PM CDT...

AT 919 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES NORTHWEST OF SULLIVAN...MOVING NORTH AT
25 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  UNION...
  WASHINGTON...
  NEW HAVEN...
  GERALD...
  BEAUFORT...
  NOSER MILL...
  LESLIE...
  LYON...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

CARNEY