Severe Thunderstorm Warning 217, NWS Paducah, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
230 PM CDT SAT SEP 23 2000

MID DAY SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING FROM MICHIGAN TO
NEAR KSGF.  THE FRONT HAS SHOWN LITTLE MOVEMENT SINCE MIDNIGHT. THE 23/12Z
700MB ANALYSIS REVEALED MID LEVEL WINDS NEARLY PARALLEL WITH THE FRONT...
SO EXPECT SLOW FORWARD PROGRESS OF THE FRONT. A SHORT WAVE ANALYZED AT
BOTH 700 & 500MB OVER MISSOURI & EVIDENT ON CURRENT WATER VAPOR LOOP WAS
GENERATING SOME PATCHY CONVECTION. THAT WILL IMPACT THE FORECAST AREA (FA)
FROM WEST TO EAST THROUGH THE AFTERNOON AND EVENING. MODELS ARE FAIRLY
CONSISTENT AND WILL GENERALLY BLEND THE ETA AND NGM (THE AVN VORT MAX, +35
UNITS IS MUCH STRONGER THAN NGM/ETA). FORECAST ISSUES WILL BE POPS AND TEMPS.

MOST NOTEWORTHY UPPER AIR FEATURE IS THE STRONG POSITIVE TILTED TROUGH
CURRENTLY OVER THE ROCKIES. 60HR ETA SOLUTION PLACES THIS TROUGH AND
ASSOCIATED 24 UNIT VORT MAX OVER FA MONDAY.  THE STRENGTH OF THIS UPPER AIR
FEATURE AND THE ANTICIPATED TIMING JUSTIFIES LIKELY POPS FROM SUNDAY
AFTERNOON THROUGH MONDAY AFTERNOON.  THE PRECIP MAKER OVERNIGHT AND THROUGH
THE FIRST HALF OF SUNDAY WILL BE RELATED THE FRONTAL PASSAGE. A WEAKER SHORT
WAVE (I.E. 10 UNIT VORT MAX) WILL IS PROGGED TO EJECT EAST FROM ROCKY MTN
TROUGH. 850MB CONDENSATION PRESSURE DEFICIT HOVERED AROUND 100MB THROUGH 00Z.
AS THE SYSTEM PROGRESSES INTO SUNDAY...THESE VALUES LOWER TO BELOW 50MB.
LOW LEVEL WINDS ON WARM SIDE OF FRONT WILL BE NEARLY PERPENDICULAR...CREATING
GOOD OVERRUNNING BY SUNDAY.  LOW LEVEL MOISTURE (I.E. 850MB RH, +80%) WILL
REMAIN HIGH.  WILL GO WITH CHANCE POP OVERNIGHT AND TRANSCEND INTO LIKELY
SUNDAY...AS ATMOSPHERE BECOMES INCREASINGLY FAVORABLE FOR RAIN.

CLOUDS WILL LIMIT DIURNAL TEMP RISE ON SUNDAY.  AGRESSIVE COLD AIR ADVECTION
BY MONDAY (850MB TEMPS DIP INTO SINGLE DIGITS) AND CLOUD COVER WILL LIMIT
HIGH TEMPS TO COLDEST SINCE APRIL 2000. WILtL BLEND FAN/FWC VALUES FOR TEMPS.

.PAH...NONE.

PGW