Hail in Kentucky, August 27, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
320 PM EDT TUE AUG 27 2002

...FORECAST ISSUES...
MAIN FORECAST CHALLENGE CONTINUES TO BE POPS...ESPECIALLY IN THE
SHORT TERM.

...MODELS/ZFP...
MODELS IN GENERALLY AGREEMENT WITH THE OVER WEATHER PATTERN IN THE
SHORT TERM.  MAIN FEATURE THAT WILL BE INFLUENCING OUR WEATHER OVER
THE NEXT COUPLE OF DAYS IS A COMPACT UPPER LEVEL CUTOFF LOW.  THIS
FEATURE IS EXPECTED TO MOVE SOUTHWARD AND OPEN UP AS THE WEST
ATLANTIC RIDGE EXPANDS WESTWARD TOWARDS THE WEEKEND.  MAIN FORECAST
CHALLENGE IN THE NEAR TERM IS POPS.  TAKING A LOOK AT THE WATER
VAPOR SAT LOOPS OVER THE LAST 12 HOURS SHOWING THE UPPER LEVEL LOW
ACTUALLY SCOOTING A LITTLE TO EAST AND MAYBE A HAIR TO THE
SOUTHEAST. WITH DAYTIME HEATING KICKING IN...SHOWERS AND
THUNDERSTORMS FIRING ACROSS THE REGION.  EXPECT SHOWERS AND STORMS
TO CONTINUE THROUGH THE EVENING HOURS AND DIMINISH AFTER SUNSET.
MAV/FWC/MET NUMBERS ARE CLOSE AND A BLEND WILL BE USED.

MODELS PEG A BIT MORE MOISTURE AND BETTER LIFT...MAINLY MID-LEVEL
ISENTROPIC LIFT...OVER THE AREA TOMORROW AND MOS NUMBERS POINTED AT
LIKELY POPS...THUS PLAN ON RUNNING 60 POPS ACROSS THE AREA.
MAV/FWC/MET NUMBERS AGAIN PRETTY CLOSE AND A BLEND WILL BE USED.
FOR THU-FRI...MORE OF THE SAME...ALTHOUGH WITH LOW A LITTLE FURTHER
TO THE SOUTH...SHOULD SEE MORE OF PARTLY CLOUDY SKIES RATHER THAN
MOSTLY CLOUDY.  WILL CONTINUE TO RUN CHANCE POPS THROUGH THE PERIOD.

...EXTENDED...
IN THE EXTENDED PERIOD...UPPER LEVEL RIDGE OVER THE WESTERN ATLANTIC
IS FORECAST TO BUILD WESTWARD THROUGH THE WEEKEND.  HOWEVER...BY THE
END OF THE HOLIDAY WEEKEND...HEALTHY H5 WAVE SCOOTING ACROSS THE
NORTHERN PART OF THE COUNTRY WILL HELP FLATTEN THE RIDGE AND LEAD TO
MORE ZONAL FLOW ACROSS THE REGION.  AS TO THE DETAILS OF THE
FORECAST...WITH THE WEST ATLANTIC RIDGE BUILDING WESTWARD INTO THE
AREA OVER THE FIRST PART OF THE WEEKEND (SAT/SUN)...QUESTION IS WHAT
TO DO WITH POPS. MEX NUMBERS ARE RUNNING IN THE 40-50 PERCENT
RANGE.  HOWEVER...NOT REAL CONFIDENT WITH THE STRENGTH OF THE RIDGE
AT THIS TIME.  SURFACE WINDS EXPECTED TO REMAIN SOUTHERLY...SO
MOISTURE SHOULD NOT BE TOO MUCH OF A PROBLEM.  WITH PARTLY CLOUDY
SKIES...EXPECT TO SEE SOME SCATTERED CONVECTIVE DEVELOPMENT
ESPECIALLY IN THE AFTERNOON AND EARLY EVENING.  SOUTHERLY FLOW
BECOME MORE SOUTHWEST AS WE GET TOWARDS MON/TUE.  AGAIN...EXPECT
MORE OF THE SAME WITH SCATTERED ACTIVITY DEVELOPING IN THE
AFTERNOON.  FOR NOW...PLAN ON RUNNING LOW CHANCE POPS THROUGH THE
WEEKEND (30 PERCENT).  IF FUTURE MODEL RUNS SUGGEST A STRONGER RIDGE
IN PLACE...THEN WILL NEED TO BACK OFF POPS A LITTLE MORE.  AS FAR AS
TEMPERATURES GO...AFTERNOON HIGHS IN THE MID 80S LOOK LIKE A GOOD
BET...WITH OVERNIGHT LOWS IN THE MID 60S...WHICH IS IN LINE WITH THE
LATEST MEX NUMBERS.

...GRIDS...
CURRENT FORECAST DATABASE IN GOOD SHAPE.  RELOADED DAYS 6 AND 7 FROM
MRF AND ADJUSTED THEM TO MESH WITH SURROUNDING SITES.  ALSO DID THE
USUAL RELOAD OF WINDS FROM THE MESO ETA FOR THE FIRST SIXTY HOURS.
ELSEWHERE...ONLY MINOR TWEAKS AND SMOOTHING WERE DONE TO EXISTING
FORECAST ELEMENTS.

...PRELIM NUMBERS...

LOZ 65/81 64/80 4645
JKL 65/79 64/80 4644

.JKL...NONE.

JARVIS

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MIDDAY UPDATE
1240 PM EDT

DILEMMA TODAY WAS WHETHER TO LOWER POPS FOR THE AFTERNOON. TRIED TO
HOLD OFF...BUT WITH VERY LITTLE HAPPENING AND LIKELY POPS GOING IN
ALL AREAS EXCEPT THE FAR NORTH...THINK THAT A CHANGE IS NEEDED.
THINK THAT SCATTERED CONVECTION WILL OCCUR...BUT THAT NGM MOS POPS
ARE JUST TOO HIGH. WILL DROP POPS SLIGHTLY WHICH WILL ALLOW
CHANCE/SCATTERED WORDING IN THE ZFP INSTEAD OF LIKELY. WILL ALSO
RAISE TEMPS TO THE LOWER 80S ALONG THE TN BORDER...WHERE AMPLE
SUNSHINE HAS OCCURRED AND MIDDLESBORO WAS ALREADY UP TO 80. WILL GO
PARTLY CLOUDY BY THE TN BORDER AND CONSIDERABLE CLOUDINESS.
ELSEWHERE.

HAL

---------------------------------------------------------------------
EARLY MORNING DISCUSSION

300 AM EDT TUE AUG 27 2002

MAIN FCST CONCERNS CONTINUE TO STEM AROUND PCPN CHANCES. ALSO STILL
CONCERNED ABOUT THE POTENTIAL FOR HEAVY RAINS...AT LEAST OF THE
ISOLATED NATURE.

SAT PICS THIS MORNING SHOW THE UPPER LOW NOW NEAR THE CENTRAL TN/KY
BORDER. SFC CHART SHOWS HIGH PRESSURE OVER THE GT LAKES AND A WEAK
LOW OVER E TN WITH AN INVERTED SFC TROFF THRU CENTRAL KY. OTHER WEAK
LOWS FURTHER S AND SE. RADAR THIS MORNING LOOKS SIMILAR TO 24 HOURS
AGO WITH SHOWER ACTIVITY CREEPING UP THRU E TN AND THEN MORE SHOWERS
MOVING WEST ACROSS CENTRAL KY. NOT MUCH IN OUR CWA ATTM.

MAIN FCST CONCERN TODAY IS POTENTIAL FOR HVY PCPN. MODELS CONTINUE
TO LOOK RATHER ANEMIC AND QPF LOOKS VERY LACKING. HARD TO PINPOINT
WHERE THE HEAVIEST RAINS WILL BE TODAY...BUT BEST THETA-E...DIV
ALOFT..OMEGA, MOISTURE CONVERGENCE, ETC, APPEARS TO BE LATE
MORNING-MIDDAY ACROSS THE SOUTHERN AND SOUTHEAST-EAST MOST ZONES.
PWS NOT TOO EXCESSIVE. ISENTROPIC LIFT LOOKS PRETTY GOOD THOUGH. AM
WORRIED THAT WHAT HAPPENED YESTERDAY MORNING COULD HAPPEN AGAIN
TODAY WITH SOME BIG HEAVY RAINERS DEVELOPING AFTER SUNRISE. DONT
THINK THERE WILL BE WIDESPREAD EXCESSIVE RAINS THOUGH AND PREFER TO
HOLD OFF ON FLASH FLOOD WATCH. HPC AGREES THAT ISOLATED HEAVY
RAINERS ARE POSSIBLE TODAY IN OUR CWA. RAINFALL RATES YESTERDAY
MORNING WHERE BORDER LINE INCREDIBLE (BUT A FEW CO-OP REPORTS
VERIFIED THESE TO SOME EXTENT) AND RADAR ESTIMATES OF SOME 4-10
INCHES FELL ACROSS PORTIONS OF SOUTHERN CWA YESTERDAY MORNING.
IN LIGHT OF ALL OF THIS AND LOCATION OF UPPER LOW...WILL GO LIKELY
POPS TODAY ACROSS S 2/3 OF THE CWA. FEEL THERE WILL BE A STRONG PCPN
GRADIENT ACROSS THE NORTHERN MOST ZONES OR NEAR/ALONG THE OHIO
RIVER. WILL MENTION HEAVY RAINS POSSIBLE TODAY ACROSS S 2/3 OF THE
CWA. COULD BE SOME HAIL AGAIN TODAY IN A FEW OF THE STORMS..SIMILAR
TO YESTERDAY ALSO. HIGHS TODAY NEAR OR AROUND 80...MAYBE UPPER 70S
IN A FEW LOCALS.

WILL CONTINUE WITH CHC POPS TONIGHT AND RIGHT ON THRU MOST OF THE
REST OF THE WEEK. NGM MOS IS GOING WITH CAT POPS TONIGHT AND
TOMORROW AND IM HAVING A HARD TIME SEEING THIS. AS THE UPPER LOW
WEAKENS SOMEWHAT AND DRIFTS A LITTLE FURTHER AWAY...POP TRENDS
SHOULD LOWER SOMEWHAT THRU THE PERIOD. ALSO SHOULD SEE SOME DIURNAL
TRENDS AS WELL (HIGHER POPS AT DAY AND A LITTLE LOWER AT NIGHT) SO
TWEAKED THE DATABASE SOMEWHAT TO REFLECT THIS.

NO CHANGES PLANNED FOR THE EXTENDED ATTM. STILL A CHANCE OF
SHOWERS/TSRA THIS WEEKEND AND WILL LEAVE LABOR DAY DRY. NOT QUITE
SURE WHAT TO THINK OF WESTWARD MOVING WARM FRONT OR INVERTED TROFF
ON THU-FRI. AS HEIGHTS RISE THIS WEEKEND ONE WOULD THINK THAT
TEMPS WOULD RISE ALSO AND POPS WOULD LOWER BUT AVN/MRF DONT SEEM TO
THINK SO YET. HAVE TAPERED POPS DOWNWARD IN THE DATABASE THOUGH.

GFE/IFPS...DATABASE LOOKS GOOD. MINOR TWEAKS HERE AND THERE AND IS
ALL AND SOME SMOOTHING. DIDNT LOAD ANY NEW DATA. ISC GRIDS LOOK
FAIRLY CLOSE.

MOS...NGM MOS POPS LOOK OVERDONE TONIGHT AND TOMORROW AND WILL USE A
BLEND. AVN POPS STILL TOO LOW. TEMPS SIMILAR.

WORK ZONES OUT BEFORE TOO LONG UNDER SDFOZFJKL. THANKS TO HPC AND
WFOS FOR CHAT ROOM COORD THIS AM.

HALL