Severe Thunderstorm Warning 72, NWS Jackson, KY

AREA FORECAST DISCUSSION
WEATHER SERVICE JACKSON KY
357 AM EDT SUN MAY 11 2003

CURRENT SFC MAP FEATURES DEEPENING LOW PRESSURE IN SOUTHWEST
WISCONSIN WITH TRAILING COLD FRONT PARALLEL WITH THE MS
RIVER...BEFORE IT SWINGS BACK ACROSS TEXAS PANHANDLE. ONGOING
CONVECTIVE LINE CONTINUES TO TRACK EAST. A FEW CELLS HAVE TRIED TO
GET GOING OUT AHEAD OF THE MAIN LINE NOW INFILTRATING CENTRAL
KENTUCKY...HOWEVER THEY SEEM TO WEAKEN QUICKLY DURING THEIR
EVOLUTION. MAIN THREAT FROM THESE STORMS STILL APPEARS TO BE
DAMAGING WINDS AND WILL STRESS THAT IN ZONE WORDING. LINE LOOKS TO
BE KNOCKING ON OUR DOORSTEP BETWEEN 9 AND 10Z. TOTAL EVENT TIME
SHOULD BE BETWEEN 2 AND 3 HOURS AT A GIVEN POINT...AS FRONTAL
BOUNDARY HAS A GOOD PUSH BEHIND IT. DESPITE FAST MOVING
CONVECTION...A FEW OF THE LIGHT FFG VALUED COUNTIES WILL HAVE TO BE
MONITORED AS PRECIP MOVES OVER THEM. WINDS WILL INCREASE INTO THE
AFTERNOON...HOWEVER DONT FEEL CONFIDENT WITH GETTING 45 MPH
GUSTS...SO WILL HOLD OFF ON WIND ADVISORY. LITTLE CHANGES MADE TO
THE FORECAST AFTERWARDS...AS MONDAY WILL FEATURE A COOLER THAN
NORMAL DAY...WITH TEMPS RECOVERING TO NEAR NORMAL VALUES BY TUESDAY.
GFS HAS POPS HOLDING BACK A LITTLE LATER FOR SYSTEM COMING IN
WEDNESDAY AND THURSDAY. WILL LET DAY SHIFT HANDLE THIS. THE NEW LONG
RANGE GFS HAS DIFFERED QUITE A BIT FROM PREVIOUS RUN. THE
NON-PROGRESSIVE CUTOFF LOW THAT WAS PROGGED TO HANG AROUND FOR
SEVERAL DAYS IS NOW BEING EJECTED OUT. GOOD RIDDANCE.

.JKL...NONE.

GEOGERIAN

---------------------------------------------------------------------
1010 PM EDT SAT MAY 10 2003

WILL UPDATE THE ZONES TO DROP THE WATCH AND FINE TUNE POP/SVR THREAT
LATER TONIGHT FROM THE WEST. REST OF FORECAST IS IN GOOD SHAPE.
UPDATE TO GRIDS...WEB GRAPHICS AND TEXT PRODUCTS OUT SHORTLY.

GREIF
=====================================================================
644 PM EDT SAT MAY 10 2003

...FORECAST UPDATE...

TORNADO WATCH BOX #343 HAS BEEN ISSUED FOR THE NORTHEAST PART OF OUR
CWA.  TORNADO WATCH #339 WILL BE ALLOWED TO EXPIRE AT 700 PM EDT.
WILL SEND OUT AN UPDATE TO THE ZONES SHORTLY.

JARVIS
=====================================================================
...FORECAST ISSUES...

MAIN FORECAST PROBLEM IS SEVERE WEATHER EPISODE FOR THIS AFTERNOON
THROUGH EARLY SUNDAY MORNING.  NEXT FORECAST PROBLEM IS THE CLEARING
OF THE CONVECTION AND CLOUDS FOR SUNDAY/SUNDAY NIGHT.

...SHORT TERM...

MID-LEVEL WAVE AND SPEED MAX SCOOTING THROUGH THE OHIO VALLEY THIS
AFTERNOON IS HELPING FIRE OFF CONVECTION ACROSS OUR AREA. IN
ADDITION...LOTS OF OUTFLOW BOUNDARIES FROM OVERNIGHT CONVECTION AND
STRONG DIFFERENTIAL HEARING HELPING INITIATE SHOWERS AND
THUNDERSTORMS ACROSS THE AREA. OUTFLOW BOUNDARY JUST NORTHEAST OF
JKL HELPED SPAWN SOME GOOD STORMS THAT CONTINUE TO DEVELOP AND HEAD
NORTHEAST.  LATEST DAY ONE OUTLOOK HAS THE NORTHERN PART OF CWA IN A
HIGH RISK OF SEVERE THIS AFTERNOON THROUGH SUNDAY MORNING WITH THE
REST OF THE CWA IN A MODERATE RISK.  TORNADO WATCH BOX #339 IN
EFFECT FOR EASTERN HALF OF CWA UNTIL 7 PM EDT.

MAIN FORECAST CHALLENGE WILL BE SEVERE POTENTIAL.  LOOKING AT MAINLY
TWO TYPES OF EVENTS.  THE FIRST WILL BE SCATTERED AFTERNOON ACTIVITY
THAT FORMS FROM A COMBINATION OF DAYTIME HEATING AND RESIDUAL
CONVECTIVE OUTFLOWS FROM PREVIOUS CONVECTION.  SECOND AND MORE
POTENT THREAT COMES IN THE FORM OF AN INTENSE SQUALL LINE THAT IS
FORECAST TO SURGE THROUGH THE REGION.  USING A BLEND OF THE
MODELS...IT APPEARS THAT SQUALL LINE WILL BE KNOCKING ON THE DOOR OF
OUR WESTERN COUNTIES BETWEEN 3 AND 5 AM.  EXPECT THE LINE THROUGH
MUCH OF OUR AREA BY 16Z OR SO.  WITH THIS LINE EXPECT MAINLY A WIND
DAMAGE EVENT...HAIL POSSIBLE AS WELL AND WITH BOW ECHO
STRUCTURES...COULD ALSO SEE SOME ISOLATED TORNADOES.

FOR TONIGHT AND SUNDAY...WILL GO WITH LIKELY POPS...MAINLY LATE
WORDING AND MENTION HIGH WINDS/HEAVY RAIN AS THE LINE PASSES THROUGH
THE AREA. WITH LINE CROSSING THROUGH THE HEART OF OUR CWA AROUND
12Z...WILL CONTINUE LIKELY WORDING ESPECIALLY THROUGH MID
MORNING...SIMILAR TO PREVIOUS PACKAGE.  TEMPS SOMEWHAT
TRICKY...CONSIDERING HOW MUCH CLEARING WE SEE.  FOR NOW...71 TO 76
LOOKS GOOD.  WILL CONTINUE TO KEEP SUNDAY NIGHT DRY WITH LOWS NEAR
50.

FOR MONDAY AND TUESDAY...PARTLY SUNNY SKIES EXPECTED WITH DRIER AND
COOLER AIRMASS IN PLACE.  MAV/FWC/MET NUMBERS LOOK GOOD WITH MID 60S
ON MONDAY WITH A GRADUAL WARM UP ON TUESDAY WITH HIGHS IN THE UPPER
60S TO LOWER 70S.

...EXTENDED...

MODELS IN GENERAL AGREEMENT IN THE EXTENDED PERIOD AS WE BEGIN WITH
A TROF WEST/RIDGE EAST PATTERN.  EXTENDED MODELS WANT TO BREAK THIS
PATTERN DOWN WITH MORE OF FAST AND ACTIVE SPLIT FLOW PATTERN.  WITH
THE NORTHERN BRANCH BEING THE DOMINATING ONE.  AS WE MOVE INTO MID
WEEK CYCLOGENESIS SPINS UP ACROSS THE SOUTHERN PLAINS.  MODELS HAVE
SOME DISAGREEMENT WITH THE OVERALL EVOLUTION AND MOVEMENT OF THIS
PLAINS SYSTEM.  THE GFS PULLS THE PLAINS SYSTEM TO THE EAST BY THE
WEEKEND AND THEN DEVELOPS A LARGE CUT OFF SYSTEM.  YESTERDAYS GFS
SOLUTION HAD SOME SUPPORT FROM THE OTHER MODELS (GEM/NOGAPS)...BUT
NOT THIS TIME AROUND.  PREFER ECMWF...SO DOES HPC...AND LOOK FOR A
MORE PROGRESSIVE PATTERN. AS FOR OUR SENSIBLE WEATHER...TUESDAY AND
WEDNESDAY LOOK TO BE PARTLY SUNNY...HOWEVER...MOISTURE WILL RETURN
BY LATE WEDNESDAY.  WILL CONTINUE PREVIOUS FORECAST AND MENTION A
SLIGHT CHANCE OF SHOWERS ON WEDNESDAY.  THURSDAY THROUGH SATURDAY
LOOK UNSETTLED AS THE PLAINS SYSTEM HEADS EAST.  AS FOR TEMPS...NOT
MUCH CHANGE FROM PREVIOUS FORECAST PACKAGE...GENERALLY FOLLOWED GFS
ENSEMBLE MEANS FOR THE EXTENDED.

...PRELIM NUMBERS (NOT OFFICIAL)...

LOZ 66/75 49/66 7711
JKL 65/75 49/64 7711

JARVIS

KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120-121100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON KY
633 AM EDT SUN MAY 11 2003

...SEVERE THUNDERSTORM WATCH IN EFFECT FOR ALL OF EASTERN KENTUCKY
THROUGH 10 AM...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN KENTUCKY.

.DAY ONE...TODAY AND TONIGHT.

STRONG TO SEVERE THUNDERSTORMS WILL MOVE THROUGH EASTERN KENTUCKY
THIS MORNING. DAMAGING WIND GUSTS ARE THE MAIN THREAT FROM THESE
STORMS...HOWEVER LARGE HAIL AND AN ISOLATED TORNADO ARE ALSO A
POSSIBILITY.

EARLY PREPARATION IS THE KEY TO SURVIVAL OF SEVERE WEATHER. IF YOU
LIVE IN A MOBILE HOME...HAVE A BACKUP PLAN TO MOVE QUICKLY INTO A
NEARBY STURDY SHELTER IF A WARNING IS ISSUED.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

THERE IS A CHANCE OF THUNDERSTORMS FROM WEDNESDAY THROUGH SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS AND LAW ENFORCEMENT OFFICIALS ARE ENCOURAGED TO REPORT ANY
SEVERE WEATHER THIS MORNING TO THE NATIONAL WEATHER SERVICE OFFICE
IN JACKSON.

GEOGERIAN