Severe Thunderstorm Warning 138, NWS St. Louis, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
330 PM CDT TUE JUL 24 2001

PCPN THREAT AND TMPS RMN THE BIGGEST FCST CHALLENGES THIS FCST
PCKG...SPCLY THRU 60H.  MDLS CONT TO DIFFER ON HANDLING OF THE FNT
CURRENTLY DRAPPED ACRS THE UPR MIDWEST INTO THE PLAINS WITH THE AVN
RMNG THE MOST AGRSV MDL IN SINKING THE FNT SWD THRU THE CWFA.  THE
ETA AND NGM ARE VERY CLOSE AND SLOWER...AND CONT TO GET A TAD SLOWER
WITH EACH SUCCESSIVE RUN.  MY BLF IS THE AVN IS A BIT QUICK AND IT'S
TENDENCY TO BLOW UP VORTS WITH PCPN AND THE EFFECTS ON THE SFC PRES
FIELD AND WNDS IS CAUSING THIS.  I'M ALSO STILL NOT TOTALLY BUYING
INTO THE DP SWD PUSH OF THE FNT IN THE LATER PDS...AND AM MORE
INCLINED TO BLV IT WL HANG UP IN THE SRN OZARKS OR BOSTON MTNS.

IN THE NR TERM...REMNANTS OF MCS WHICH EFFECTED SE MO THIS MRNG CONT
TO PUSH INTO NRN AR WITH OUTFLOW BNDRY NOW INITIATING DVLPMNT OVR SW
MO.  ASSOCD VORT OVR SE MO SHUD CONT TO SINK SWD AND THIS SHUD BE A
NON-FACTOR IN THE FCST TNGT.  QUESTION WL BE DVLPMNT FURTHER NORTH
OVR THE SRN HALF OF IA ASSOCD WITH CNVCTVLY ENHANCED VORT MOVG INTO
WRN IA.  LOW LVL INFLOW OVR MO IS CURRENTLY BEING EFFECTED BY
AFOREMENTIONED SE MO SYS...BUT LATER TNGT IT SHUD BGN RESPONDING TO
NRN SYS AND BCM DECIDELY SWLY.  THIS IS FCST TO RESULT IN A BROAD
E-W ORIENTED ZN OF MCON AND LIFT IN ADVANCE OF THE CDFNT FM
NRN/CNTRL IL ACRS NRN MO.  THE SLOWING SWD SAGGING FNT AND THIS
INCRS IN LRG SCALE SUPPORT WUD CONT TO FAVOR HI POPS TNGT OVR NRN
SXNS OF THE CWFA.  LESS FOCUSED WAA ASSOCD WITH THE SWLY LLJ WL
RESULT IN ENUF LIFT TO SUPPORT CHC POPS CNTRL MO INTO SW IL.  A
QUICK LK AT THE NEW 18Z ETA IS INTERESTING AS IT REALLY DRIVES PCPN
SWD TNGT FM IA AND DP INTO MO.  THE FCST FOR 21Z ALREADY LKS TOO FAR
SOUTH AND THIS MAY BE RELATED TO TDAS CHGS IN THE EDAS.

FOR WED ALOT HEDGES ON THE AMT OF CLDS AND PCPN.  THE 12Z ETA AND
AVN BOTH SUGGEST SOME SORT OF MCS WL SINK SEWD FM NW MO DURING THE
MRNG WITH BOTH IT'S OUTFLOW AND DEBRIS CLD EFFECTING A LRG PTN OF
OUR CWFA TO A DEGREE.  CLDS AND THREAT OF PCPN WUD ARGUE FOR KPG THE
TMPS DOWN FM THE WARM FWC VALUES AND MORE OR LESS A BLEND OF GUID.
IF THE MCS AND DEBRIS DON'T PAN OUT THEN THE WARMER NUMBS CERTAINLY
AREN'T OUT OF THE QUESTION AS THE FAVORED ETA/NGM HV THE FNT OVR THE
NRN PTN OF OUR CWFA AT 00Z/THURS WITH SW SFC WNDS.  HV GONE WITH HI
CHC OR LIKELY POPS GIVEN BNDRYS AND VERY MOIST AND UNSTBL AMS IN
PLACE ACRS THE RGN.

AGAIN FOLLOWING THE SLOWER FNT TIMING...HV INCRS POPS WED NGT AND
CONTD THEM OVR THE SRN HALF OF THE CWFA ON THURS.  DRIER AND
RELATIVELY COOLER AIR WL BLD INTO THE RGN IN THE WAKE OF THE FNT
EVENTUALLY SPRDG ACRS MOST OF THE CWFA THURS INTO FRI.

ALL HEAT WARNINGS HV EXPIRED WITH THIS ZN PCKG. THIS SHUD BE OK
UNLESS THE CLDS AND PCPN BUST TMW AND THEN WE MAY FLIRT WITH THE 105
HI MARK IN THE AFT.

.STL...NONE
GLASS

ILZ095-096-250530-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
1200 AM CDT WED JUL 25 2001

...SEVERE THUNDERSTORM WATCH FOR ADAMS AND BROWN COUNTIES ILLINOIS
CANCELLED...

THE SEVERE THUNDERSTORM WATCH FOR PARTS OF SOUTHWEST ILLINOIS...
INCLUDING THE CITY OF QUINCY...HAS BEEN CANCELLED. SCATTERED SHOWERS
AND THUNDERSTORMS WILL CONTINUE THROUGH THE EARLY MORNING HOURS...
BUT SHOULD REMAIN BELOW SEVERE LIMITS.

qWDB