Severe Thunderstorm Warning 145, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
300 PM EDT SUN AUG 18 2002

18Z SFC ANALYSIS SHOWS A COLD FRONT...OR MESOSCALE OUTFLOW BOUNDARY
FROM THE EARLIER MCS AND COLD POOL...NOW LYING NORTHEAST TO
SOUTHWEST ACROSS CENTRAL AND KENTUCKY. SATELLITE AND RADAR DETAIL A
CHARGED SITUATION WITH RENEWED MCS ACTIVITY OVER SOUTHEAST INDIANA
ENTERING OHIO AND A CLUSTER OF STORMS DEVELOPING OVER CENTRAL
KENTUCKY AHEAD OF/ALONG THE FRONT.

THE MODELS CONTINUE IN GOOD AGREEMENT ALOFT AS A BROAD TROUGH SWINGS
THROUGH THE OHIO VALLEY TONIGHT AND MONDAY. THIS TROUGH WILL BE
ACCOMPANIED BY A SERIES OF SHORTWAVES. THE FIRST OF THESE...
RESPONSIBLE FOR THE MCS ACTIVITY TO OUR NORTHWEST...WILL DROP
THROUGH CENTRAL KENTUCKY THIS EVENING WITH ANOTHER ARRIVING ON ITS
HEELS MONDAY MORNING. THE LAST OF THESE...WEAKER THAN THE EARLIER
ONES...DRIFTS THROUGH THE AREA TUESDAY MORNING. IN THE WAKE OF ALL
THIS...FOR MID WEEK...A DEEPENING TROUGH IN THE PACIFIC NORTHWEST
WILL PUMP THE RIDGE OVER THE MID SECTION OF THE NATION. THIS RIDGE
THEN BUILDS INTO THE LOWER OHIO VALLEY AND DOMINATES THE AREA
THROUGH THE END OF THE WEEK. THAT IS...UNTIL IT RETROGRADES AND
ALLOWS LOWER HEIGHTS...AND ADDITIONAL SHORTWAVE ENERGY...TO AFFECT
THE EASTERN OHIO VALLEY FRIDAY AND SATURDAY.

SENSIBLE WEATHER WILL START WITH A BANG AS NUMEROUS LATE AFTERNOON
AND EVENING THUNDERSTORMS WILL ROLL INTO NORTHEAST KENTUCKY EITHER
AS AN MCS OR THE REMAINS OF THE CURRENT ONE MOVING INTO SOUTHWEST
OHIO. ADDITIONAL...SCATTERED STORMS WILL BE THE RULE FOR THE REST OF
THE AREA EARLY ON. THESE STORMS ARE BEING FUELED BY THE STRONG VORT
RIDGE RIDING THROUGH THE AREA WITH PLENTY OF LOW LEVEL MOISTURE AS
DEWPOINTS ARE IN THE LOWER AND MIDDLE 70S THROUGH CENTRAL AND
EASTERN KENTUCKY. WILL LIKELY MAKE LAST MINUTE CHANGES TO THE WORK
ZONES AND GRIDS TO BETTER HANDLE THE SHORT TERM WEATHER.

THERE SHOULD BE A DIURNALLY DRIVEN RESPITE LATER TONIGHT. WITH
ACTIVITY RENEWING DURING THE DAY MONDAY AS THE NEXT PULSE PULLS THE
FRONT BACK NORTH. THIS WAVY FRONT AND THE UPPER TROUGH/S LAST HURRAH
WILL GO THROUGH MONDAY NIGHT WITH DRIER AIR RAPIDLY MOVING INTO THE
STATE ON TUESDAY. DRY AIR AND A BUILDING UPPER RIDGE WILL KEEP THE
WEATHER QUIET THROUGH THE REST OF THE WEEK AS TEMPERATURES CLIMB
BACK ABOVE NORMAL FOR AFTERNOON HIGHS. THE SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS WILL RETURN LATE FRIDAY AS ANOTHER FRONT ATTEMPTS
TO COME DOWN AND THE RIDGE RETREATS.

AS FOR IFPS/GFE...THE USUAL REPOPULATION WITH MESOETA WINDS/TEMPS
AND TDS. TWEAKED THESE AND THE REST OF THE GRIDS. KEPT MID WEEK
DRY AND A CHANCE TO SLIGHT CHANCE THE REST OF THE TIME WITH DIURNAL
PEAKS IN CLOUDS AND POPS EACH AFTERNOON.

MOS NUMBERS ARE SIMILAR FOR THE NGM AND AVN...THESE LOOK REASONABLE.
WILL NOT STRAY FAR. WILL GO A LITTLE HIGHER THAN MOS FOR POPS
TONIGHT GIVEN THE CURRENT ACTIVITY...OUTFLOWS THAT WILL RESULT FROM
THIS...AND THE FACT THAT SHOWERS POPPED UP THROUGH THE NIGHT LAST
NIGHT.

WORK ZONES AVAILABLE BEFORE TOO LONG UNDER THE AFOS PRODUCT
SDFOZFJKL.

PRELIMINARY CCFS:
LOZ TB 068/087 066/088 353
JKL TB 070/086 067/087 453

.JKL...NONE

GREIF

PREVIOUS DISCUSSIONS FOLLOW:
---------------------------------------------------------------------
1135 PM EDT SUN AUG 18 2002

14Z SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY DRAPED FROM NORTHEAST
OHIO THROUGH SOUTHERN INDIANA...DOWN TO SOUTHERN MISSOURI. DYING
COMPLEX OF STORMS IN EASTERN MO AND SOUTHERN IL SPREADING CIRRUS OUT
AHEAD OF IT. SOME STORMS ALREADY FIRING ALONG THE OHIO RIVER WHERE
THE SUNSHINE HAS BEEN MORE PREVALENT. DESPITE STUBBORN LOW CLOUD
COVER...TEMPERATURES STILL CLIMBING. ALSO A FEW STRAY SHOWERS TRYING
TO FIRE. WILL UPDATE WORDING TO SAY MOSTLY CLOUDY...BUT WILL KEEP
MID 80S FOR TEMPS AND POPS GOING 50 IN THE NORTH...AND 40 IN THE
SOUTH.

GEOGERIAN

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ALTHOUGH SOME DIFFERENCES EXIST IN THE MODELS IN THE HANDLING OF THE
FRONTAL BOUNDARY TO OUR NORTHWEST...THERE IS LESS DISPARITY AND
BETTER CONTINUITY THAN IN RECENT DAYS. IT LOOKS LIKE THE FRONT
ARRIVES MONDAY NIGHT. UNTIL IT PASSES WE WILL SEE A POSSIBILITY OF
SHOWERS AND STORMS...WITH A LARGE DIURNAL EFFECT. OVER THE NEXT
COUPLE OF DAYS WILL GO WITH SLIGHTLY BETTER CHANCES IN THE
NORTH...CLOSEST TO THE FRONT. ASSUMING THE MODELS HAVE CONVERGED ON
A SOLUTION...THE FRONT SHOULD BE DROPPING TO OUR SOUTH ON
TUESDAY...AND WILL USE A DRY FORECAST THAT DAY.

GUIDANCE TEMPS ARE IN GOOD AGREEMENT FOR THE NEXT COUPLE OF DAYS AND
SEE NO REASON TO DEVIATE MUCH.

EXTENDED FORECAST...LATEST AVN SHOW FAIR CONTINUITY FROM THE RUN 24
HOURS PRIOR. IT STILL INDICATES AN UPPER RIDGE BUILDING OVER THE
AREA AT MIDWEEK...WITH WARM AND DRY WEATHER. BY THE WEEKEND THE
RIDGE RETROGRADES AND A TROUGH DROPS INTO THE NORTHEASTERN U.S.  THE
ASSOCIATED COLD FRONT APPROACHES...WITH AN INCREASE IN MOISTURE
AHEAD OF IT BRINGING A POSSIBILITY OF CONVECTION ALONG AND AHEAD OF
THE FRONT.

HAL
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900 PM EDT SAT AUG 17 2002

SAT PICS SHOWING THAT SKIES HAVE CLEARED OFF CONSIDERABLY...AT LEAST
FOR A SHORT WHILE. TIME HEIGHT SECTIONS AND FCST SOUNDINGS INDICATE
A LOT OF LL RH THRU THE NIGHT AND FAIRLY UNSTABLE ALSO. 88D SHOWING
THAT THE FIRST BIG BATCH OF SHOWERS ASSOCIATED WITH A 5H SHORTWAVE
AND A BIT OF A SFC TROFF...HAVE MOVED OFF TO THE EAST OF THE CWA.
NEW SHOWERS AND A FEW TSRA HAVE QUICKLY DEVELOPED OVER S IN AND
PARTS OF N KY. WILL KEEP AN EYE ON THIS ACTIVITY.

SFC CHART THIS EVENING SHOWING THE FRONT SLICES THRU IL AND INTO S
MO. THINK THE FRONT WILL MAKE IT A LITTLE FURTHER EAST/SE BEFORE
STALLING OUT.

ALL SAID AND DONE...PLAN ON UPDATING ZONES TO MAINLY REMOVE EVENING
WORDING. AM A BIT LEARY TO REMOVE OR LOWER POPS. MESO-ETA HINTS AT
SOME ACTIVITY LATE NIGHT AND THE RUC IS GOING HOG-WILD WITH ALL
SORTS OF PCPN TONIGHT. THIS SEEMS OVERDONE. ANOTHER PROBLEM IS FOG
TONIGHT. TEMPS ARE QUICKLY LOWERING TO NEAR DEWPOINTS AND WITH SKIES
MOSTLY CLEAR FOR THE MOMENT AND MANY AREAS SAW SHOWERS TODAY...COULD
GET FOGGY IN A BIG HURRY. HOWEVER FEEL THAT CLOUDS WILL INCREASE
SOMEWHAT LATER ON AND THIS SHOULD HELP TEMPER HOW DENSE THE FOG
BECOMES. WILL BEEF UP THE FOG WORDING A BIT BUT WILL HOLD OFF ON
DENSE WORDING. DEWPOINTS UP ABOUT 3 DEGREES FROM WHERE THEY WERE 24
HOURS AGO...SO OVERNIGHT LOWS MIGHT BE CLOSER TO 70 BUT UPPER 60S
ARE CLOSE ENUFF FOR NOW.

UPDATE OUT SHORTLY.

HALL