Severe Thunderstorm Warning 119, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
250 PM EDT FRI OCT 5 2001

BIGGEST FORECAST CHALLENGE CONTINUES TO BE TIMING OF COLD FRONT A
SUBSEQUENT POPS AND TEMPERATURES DURING AND AFTER FRONTAL PASSAGE.

THE MOST STRIKING FEATURE ON THE MAP IS A COLD FRONT DRAPED ROUGHLY
FROM NEW ENGLAND TO THE OHIO RIVER TO TEXAS.  IN OUR VICINITY...THE
FRONT IS BETWEEN EVANSVILLE AND LOUISVILLE AND WILL PICK UP SPEED AS
A SURFACE LOW NORTHEAST OF PADUCAH TRACKS NORTHEAST.  A SOLID CLOUD
SHIELD IS IN PLACE BEHIND THE FRONT...ALONG WITH MOST OF THE
RAINFALL THAT IS OCCURRING.  DEW POINTS DROP OFF DRAMATICALLY BEHIND
THE FRONT...DROPPING TO AS LOW AS THE TEENS IN NORTH CENTRAL
PORTIONS OF THE CONUS.

I LIKE THE CATEGORICAL POPS FOR TONIGHT...AND WILL PROBABLY GO WITH
SPRINKLES POSSIBLE IN THE MORNING AND LEAVE OUT POPS FOR
TOMORROW...KEEPING CLOUDS IN THE MORNING AND BREAKING UP SOMEWHAT BY
AFTERNOON.  WILL KEEP CLOUDS A BIT LONGER THAN MODELS INDICATE AS
COOL NORTHWEST FLOW WITH SOME LINGERING LOW LEVEL MOISTURE WILL BE
IN PLACE AND MODELS GENERALLY HAVE A HARD TIME HANDLING
THIS...ESPECIALLY DURING CHANGEOVER TO COOL SEASON.

TEMPS COULD BE TRICKY.  TONIGHT WILL KEEP TEMPS NEARLY THE SAME AS
PREVIOUS FORECAST...BUT MAY LOWER INTO THE LOWER 40S IN SOME
NORTHERN COUNTIES AS COLD AIR ADVECTION WILL BE QUITE STRONG AFTER
THE FRONT PASSES.  NGM MOS TEMPS WILL BE TWEAKED DOWNWARD FOR HIGHS
FOR THE NEXT COUPLE OF DAYS.  ONE BIG CONCERN WILL BE OVERNIGHT LOWS
FOR THE NEXT SEVERAL NIGHTS.  I BELIEVE A SIGNIFICANT VALLEY/RIDGE
SPLIT WILL START TAKING PLACE SUNDAY MORNING AS WE START TO
DECOUPLE.  MONDAY MORNING MAY BE QUITE COLD AS THE CENTER OF LOW
PRESSURE WILL BE NEARLY ON TOP OF THE AREA.  I DO NOT NORMALLY BREAK
OFF VALLEY/RIDGE SPLITS INTO THE EXTENDED...BUT THIS SPECIFIC
SITUATION WARRANTS THIS IN MY OPINIONS AS SEVERAL NIGHTS OF FROST
ARE PROBABLE FOR VALLEY LOCATIONS ESPECIALLY.  MONDAY MORNING WILL
PROBABLY BE THE COLDEST WITH SOME VALLEY LOCATIONS DIPPING INTO THE
UPPER 20S.  THIS SEEMS TO BE PRUDENT AS DEWPOINTS IN THE 20S TO NEAR
30 ARE HEADING OUR WAY UNDERNEATH THE DOME OF ARCTIC SURFACE HIGH
PRESSURE.  WILL MODERATE SLOWLY AS RETURN FLOW WORKS  MAKES IT BACK
INTO THE REGION.  WILL HOLD OFF CHANCES OF PRECIP TO LATE THURSDAY
INTO FRIDAY AS EASTWARD MOVEMENT OF NEXT SYSTEM APPEARS TO BE SLOWER
WITH LATER RUNS OF MODELS.

THANKS TO BNA FOR COORD CALL AGAIN TODAY.

.JKL...NONE.

HEINLEIN