Severe Thunderstorm Warning 172, NWS Louisville, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
131 PM EDT SAT JUN 15 2002

PLENTY OF DIURNAL CU EAST OF I-65 THIS AFTERNOON AHEAD OF SMALL
SCALE 500MB WAVE TRANSLATING SEWD OVER WRN IND, WITH EVEN FURTHER
DEVELOPMENT PERHAPS BEING HELD IN CHECK BY FAIRLY IMPRESSIVE 700MB
INVERSION SEEN ON 12Z KOHX RAOB.

SO QUESTION OF THE HOUR IS SH/TS CHANCES TONIGHT, FOCUSING ON PAIR
OF MID-LEVEL WAVES OVER MN/WI AT 17Z MVG TOWARDS CWA AROUND WRN SIDE
OF ERN GREAT LAKES COLD CORE LOW. FRIDAY EVENING WE HAD A FEW TS IN
NRN ZONES ASSOC WITH MORE DISCRETE (BULLS-EYE TYPE) VORTICITY MAXIMA
ROTATING CLOSER TO CENTER OF 500MB LOW, BUT TONIGHTS FEATURE IS
MORE STRINGY SO THE QG FORCING MAY NOT BE AS GREAT. BUT A 24 HOUR
COMPARISON OF ETA DATA FROM 0Z/15 TO 0Z/16 SHOWS 850MB TDS INCR BY
1-3C OVER NRN CWA WHILE 700-500MB L/RS REMAIN SIMILAR. 12Z RAOBS
DOWNSTREAM FROM THIS FEATURE AT KMPX AND KDVN ALSO SHOW PWATS NEAR
3/4 WITH VERY STEEP LOW/MID LEVEL L/RS. MORNING RUN OF LMK-MM5 IS
SHOWING BEST MOISTURE POOLING, INSTABILITY, AND 700/850MB OMEGAS
MOVING THROUGH NRN HALF OF CWA FROM 3 TO 9Z, SO WILL GO WITH CHC
SH/TS DURING THAT PERIOD PRECEDED BY A PERIOD OF P/CLOUDY OR
M/CLEAR SKIES. MAIN THREAT FROM TS WOULD BE WIND GUSTS TO 40KTS
GIVEN STEEP LOW-LEVEL L/RS AND SOMEWHAT DRY SUBCLOUD LAYER, ALONG
WITH SOME HAIL GIVEN FREEZING LEVELS NEAR 10KFT.

META/AVN SHOW SFC REFLECTION OF AFOREMENTIONED WAVE MEANDERS INTO
SRN KY AND TN OVERNIGHT INTO SUNDAY, QUESTION IS WHETHER THIS TROF
WILL FOCUS DEVELOPMENT OF PRECIP FOR LMK CWA. BOTH MODELS GO
COMPLETELY BERSERK WITH MCS DEVELOPMENT OVER SRN PLAINS TONIGHT,
HOWEVER ATTENDANT 500MB OUTFLOW JET/PV MAXIMUM WOULD APPEAR TO
PROPAGATE E/SE ACROSS THE GULF STATES, STAYING WELL SOUTH OF CWA.
BUT THERE ARE SOME INDICATIONS OF MOISTURE POOLING ALONG/AHEAD OF
THIS SFC TROF FEATURE (META PWATS AT KBWG RISE TO 1.17 BY 18Z/SUN)
THAT ILL PUT SOME SMALL CHC POPS FOR SRN HALF OF CWA SUNDAY, BEING
PURPOSELY VAGUE ON TIMING DUE TO UNCERTAINTY IN NWP SOLUTIONS. ONCE
AGAIN WITH FCST CLOUD BASES AROUND 6-8KFT, COULD SEE SOME GUSTY
WINDS WITH THESE GUYS.

MAYBE SOME STRAY SH/TS ACROSS SRN KY INTO SUNDAY EVENING BUT, ONCE
AGAIN WITH UNCERTAINTY IN AVN VS ETA FCST, WILL LEAVE DRY FOR NOW.
CWA REMAINS UNDER MID-LEVEL TROUGHINESS MONDAY WITH NORTHERLY SFC
FLOW PERSISTING, SO WILL LEAN TOWARDS COOLER MAV MAXIMA. ETA HINTING
AT ANOTHER WAVE ROUNDING 500MB TROUGH THAT MAY PRODUCE SOME SH OVER
IND, BUT NOT ENOUGH TO CONCERN ME FOR LMK CWA. MID-LEVEL FLOW
PATTERN THEN BEGINS TO TRANSITION FROM NWLY FLOW REGIME TO A RIDGE
BUILDING OVER SERN U.S. BY THE END OF THE WEEK, SPELLING MORE
SEASONABLY WARM AND HUMID CONDITIONS. WILL LEAVE DRY FOR NOW AS NO
DISCERNIBLE FORCING FEATURES NOTED IN 12Z AVN OR 0Z ENSEMBLE DATA.

.SDF...NONE.

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