Severe Thunderstorm Warning 120, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
320 PM EDT FRI JUL 14 2000

...UPDATED TO INCLUDE SEVERE THUNDERSTORMS WATCH...

MODELS ARE IN GENERAL AGREEMENT THIS FORECAST CYCLE FOR THE MOST
PART. THERE ARE SLIGHT DIFFERENCES IN THE TIMING AND PLACEMENT OF A
POTENT VORT MAX COMING DOWN THE NORTHWESTERLY FLOW EARLY IN THE
FIRST PERIOD. NGM IS SLIGHTLY FURTHER EAST WITH THE VORT MAX THAN
ETA. ANYWAY...APPEARS THAT THE NE PORTION OF OUR CWFA WILL BE MOST
AFFECTED BY THIS FEATURE. CONTINUED DIVERGENT FLOW ALOFT IS ALSO
CAUSE FOR CONCERN. SPC HAS PUT THE NE HALF OF THE CWFA IN A MODERATE
RISK AREA. WILL BREAK UP ZONES ACCORDINGLY.

FURTHER OUT...POPS BECOME PROBLEMATIC. UPPER LOW OVER ONTARIO DRIFTS
SOUTH TO THE EASTERN GREAT LAKES REGION BY 12Z SUNDAY. THIS RESULTS
IN AN EVEN MORE AMPLIFIED FLOW OVER EASTERN KENTUCKY. A SERIES OF
DISTURBANCES WILL PLUNGE DOWN THIS AMPLIFIED FLOW TOWARD THE REGION.
HOWEVER ALL MODEL TIME SECTION PROJECT A RELATIVELY DRY ATMOSPHERE
ESPECIALLY ABOVE THE BOUNDARY LAYER. FORECAST SOUNDINGS ALSO PORTRAY
MUCH LOWER PRECIP WATER VALUES THAN WHAT WE HAVE SEEN LATELY. FAN AND
FWC PROJECT RELATIVELY LOW POPS. AM INCLINED TO FAVOR PERSISTENCE IN
WHAT WE HAVE EXPERIENCED WITH THE NW FLOW REGIME AND CONTINUE A SMALL
POP THROUGH THE FORECAST PERIOD. WILL TEND TO FAVOR FWC TEMPS OVER
COOLER FAN TEMPS BASED ONCE AGAIN MOSTLY ON PERSISTENCE.

EXTENDED...MEDIUM RANGE MODELS OVERALL ARE IN REASONABLY GOOD
AGREEMENT. MRF BECOMES SOMEWHAT OUT OF PHASE WITH THE OTHER MEDIUM
RANGE MODELS IN THAT IT BUILDS THE UPPER RIDGE EAST FASTER PUTTING
EASTERN KENTUCKY IN AN ANTICYCLONIC FLOW ALOFT BY MONDAY. ALL MODELS
DEAMPLIFY THE FLOW OVER CONUS CONSIDERABLY AS THE TROUGH OVER THE
NORTHEAST LIFTS OUT AND THE UPPER RIDGE MIGRATES EASTWARD. THE
LONGWAVE PATTERN BEGINS TO AMPLIFY AGAIN BY LATE IN THE EXTENDED AS
THE EAST COAST TROUGH STARTS TO RE-ESTABLISHED ITSELF. AT ANY
RATE...RELATIVELY BENIGN WEATHER IS EXPECTED THROUGH THE EXTENDED
PERIOD ALONG WITH A MODEST WARMING TREND. BOTH THE CANADIAN GEM AND
MRF BRING PRECIP TO EASTERN KENTUCKY BY LATE WEDNESDAY. AS A RESULT
WILL INTRODUCE A CHANCE OF SHOWERS FOR WEDNESDAY.

LOZ BB 063/082 060/085 065 23211
JKL BB 064/079 060/081 066 23311

.JKL...SEVERE THUNDERSTORM WATCH FOR NORTHEASTERN KENTUCKY UNTIL 8
PM EDT.

LCM