Severe Thunderstorm Warning 25, NWS Paducah, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
200 AM CDT MON APR 23 2001

IR SATELLITE IMAGERY WITH LIGHTNING STRIKE OVERLAY HINTS THAT
CONVECTION APPEARS TO BE ON A DIMINISHING TREND UPON ITS EWARD
ADVANCE IN MO. THIS IS BECAUSE ITS GETTING AWAY FM LOW LEVEL
FORCING IN ITS SOURCE REGION AND RUNNING INTO MORE STABLE AIR...WHERE
TEMPS ALOFT ARE CAPPING ENVIRONMENT. NEW MODELS AGREE IN GRADUALLY
DESTABILIZING ATMOS AS FRONT APPROACHES...THOUGH AS MOISTURE
INCREASES INTO FA AROUND 12Z ENVIRONMENT APPEARS LIKELY TO STILL BE
CAPPED AND NOT QUITE DESTABILIZED SUFFICIENTLY TO SUPPORT THUNDER.
SO DESPITE PERHAPS AN AM CHC MAINLY WAA SHRA...BELIEVE BEST CHC
CONVECTION WL BE THIS PM. SOUNDING AND THERMO DATA REVEAL COOLING
MID LEVEL TEMPS ALLOW FOR DESTABLIZING PROFILE AND STABILITY INDICES
RESPOND BY REACHING CRITICAL T-HOLDS. IF NOT TOO MUCH CLOUDINESS FOR
PM SURFACE HEATING TO STEEPEN LOW LEVEL LAPSE RATES...COULD SEE
DECENT THUNDER ACTIVITY (SPC SLGT RISK) WITH FROPA TIMED INTO FA
DURING PEAK HEATING HOURS...DESPITE FACT BEST DYNAMICS REMAIN NORTH.

STILL APPEARS PM CONVECTION WL BE TIED TO LOW LEVEL FORCING
COINCIDENT WITH FRONTS ENTRANCE INTO FA...WHICH ETA/AVN HAVE
TRENDED WITH FASTER AND THUS BEST SOLUTIONS ON TIMING. TSMS SHOULD
DEVELOP WITHIN 850MB THETA-E AXIS ADVECTING ACROSS FA JUST IN
ADVANCE OF FRONT. TROPICAL CONNECTION AND PWS IN EXCESS OF 1 INCH
YIELD POTENTIAL FOR SOME LOCALLY HEAVIER RAINS ON RELATIVELY QUICK
MOVING STORMS...WITH TRAINING POSSIBLE DUE TO LINEAR STORM
DEVELOPMENT IN NEARLY UNIDIRECTIONAL 40-50KT LOW-MID LAYER FLOW. ETA
DIMINISHES SBASED CAPES DURING PM HOURS BUT CAPES REMAIN AOA 1K J/KG
ABOVE THE LFC. ALL NUMERICAL GUIDANCE HAS RESPONDED WITH INCREASE TO
LIKELY POPS FOR THIS PM/EVENING AND WL MAKE LIKE MODIFICATION TO
ZONE PACKAGE. STORMS WL DEPART QUICKLY OVERNIGHT WITH FRONT AND MOST
IF NOT ALL ACTIVITY EAST OF FA BY 06Z. ANY LINGERING CAA CLDS BEHIND
FRONT WL CLEAR OUT TUE AS DEEP LAYERED SUBSIDENCE AND LATE APRIL
INSOLATION DRIES OUT COLUMN.

WATER VAPOR IMAGERY STILL SHOWS A TROPICAL CONNECTION AND AM
THEREFORE INCLINED TO BACK OFF WARM MAV HIGHS FOR TODAY. HOWEVER DO
PREFER AVN BASED COOLER TEMPS OF FAN/MAV POST FROPA...WITH BETTER
GRASP ON COLD TEMPS BEHIND FRONT...CURRENTLY OBSERVED UPSTREAM.

.PAH...NONE.
DH

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-100-
107>112-114-231900-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE PADUCAH KY
1115 AM CDT MON APR 23 2001

VALID UNTIL 600 AM TUESDAY...THIS THUNDERSTORM OUTLOOK COVERS
SOUTHEAST MISSOURI...SOUTHERN ILLINOIS...SOUTHWEST INDIANA...AND
WESTERN KENTUCKY.

SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PROGRESS ACROSS THE FOUR-
STATE REGION TODAY. THERE IS A SLIGHT RISK THAT SOME OF THESE STORMS
MAY BECOME SEVERE. SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON AND
EVENING...ESPECIALLY ALONG AND EAST OF THE MISSISSIPPI RIVER.

AS OF LATE MORNING...A COLD FRONT WAS SITUATED FROM LOW PRESSURE
OVER WISCONSIN SOUTH ACROSS CENTRAL MISSOURI INTO WESTERN ARKANSAS.
THIS FRONT WILL BE THE FOCUSING MECHANISM FOR SHOWERS AND
THUNDERSTORMS AS IT PUSHES EAST ACROSS THE FOUR-STATE REGION THIS
AFTERNOON AND EVENING. LATEST SATELLITE AND RADAR LOOPS DEPICT A
NARROW BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS ALONG AND JUST
AHEAD OF THE COLD FRONT. THIS ACTIVITY WILL CONTINUE TO MAKE ITS WAY
ACROSS THE FORECAST AREA OVER THE NEXT 12 HOURS.

THE ATMOSPHERE IS FORECAST TO REMAIN MARGINALLY UNSTABLE THIS
AFTERNOON. THE BEST UPPER-LEVEL SUPPORT WILL REMAIN TO THE NORTH OF
THE AREA...THUS LIMITING THE SEVERE THREAT. HOWEVER...ISOLATED
SEVERE STORMS ARE STILL POSSIBLE...ESPECIALLY DURING THE MID AND
LATE AFTERNOON HOURS WHEN THE ATMOSPHERE WILL BE MOST UNXSTABLE.

SHOULD ANY STORMS BECOME SEVERE THIS AFTERNOON AND EVENING...VERTICAL
WIND AND TEMPERATURE PROFILES SUGGEST THE GREATEST THREAT WILL BE
DAMAGING WIND. STORM MOVEMENT WILL BE NORTHEAST AT 35 TO 40 MPH.

PRESLEY