Severe Thunderstorm Warning 143, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
330 AM EDT SUN AUG 10 2002

06Z SFC ANALYSIS SHOWS HIGH PRESSURE OVER THE SOUTHEAST WITH A WEAK
COLD FRONT LOOSING ITS CHARACTERISTICS THROUGH CENTRAL ILLINOIS AND
MISSOURI. ONCE AGAIN THIS FRONT SHOWS UP BEST ON SATELLITE AS A
BAND OF MID AND HIGH LEVEL CLOUDS STRETCHED ACROSS THE MID
MISSISSIPPI VALLEY INTO THE LOWER GREAT LAKES. SFC OBS DEMONSTRATE
THAT DEWPOINTS HAVE COME UP NICELY FROM 24 HOURS AGO WITH HIGHEST
VALUES TO THE SOUTH. EARLIER SHOWERS OVER WAYNE COUNTY DISSIPATED
TOWARD MIDNIGHT BUT INDICATES THAT IT WON/T TAKE MUCH TO GENERATE
CONVECTION IN THIS AIRMASS.

THE MODELS ARE IN DECENT AGREEMENT MAKING THE SOUTHEAST RIDGE JUST A
MEMORY AS A SLOWLY EVOLVING BROAD TROUGH SETS UP OVER THE NORTHERN
TIER OF THE NATION. THE LEAD TROUGH WITH THIS LIFTS NORTH...DEEPER
INTO CANADA...TODAY LEAVING THE AFOREMENTIONED FRONT HANGING.
HOWEVER A SECOND TROUGH TAKES THE PLUNGE TO START THE NEW WORK WEEK
AND REAMPLIFIES THE TROUGH STARTING IN THE NORTHERN PLAINS...CLOSER
TO HOME...THIS TEMPORARILY RAISES HEIGHTS OVER EAST KENTUCKY. THIS
DEEPER TROUGH AXIS THEN WORKS EAST ENDING UP IN THE UPPER MIDWEST
AND BRUSHING THE OHIO VALLEY DURING THE MIDDLE PART OF THE WEEK.
LATER IN THE WEEK THIS LIFTS OUT ALONG WITH THE WESTERLIES. THE BEST
ENERGY MOVES THROUGH EAST KENTUCKY WEDNESDAY NIGHT AND THURSDAY
MORNING. A WEAKER STREAM OF ENERGY RIDES OUT AHEAD OF THE TROUGH
AXIS EARLIER IN THE WEEK TUESDAY INTO WEDNESDAY.

FOR SENSIBLE WEATHER...THE DIURNAL CYCLE WILL DOMINATE EXCEPT IN THE
VICINITY OF A FRONT THAT TRIES TO MOVE THROUGH LATE WEDNESDAY. IN
THE MEANTIME...MOISTURE WILL BUILD THROUGH THE AREA...EXCEPT FOR A
BRIEF RESPITE ON MONDAY WHEN HEIGHTS RISE A BIT. TODAY...PWS IN THE
1.5 TO 1.75 INCH RANGE...LITTLE IN THE WAY OF A CAP AND UPPER LEVEL
DIVERGENCE SHOULD BE ENOUGH FOR SCATTERED SHOWERS AND THUNDERSTORMS
THIS AFTERNOON. FOR MONDAY WILL KEEP POPS IN THE SLIGHT CHANCE
CATEGORY DUE TO SLIGHTLY LESS FAVORABLE CONDITIONS. TUESDAY AND
WEDNESDAY CHANCES ALSO LOOK GOOD AHEAD OF THE FRONT WITH PLENTY OF
MOISTURE IN PLACE AND WEAK VORTS AROUND. THE FRONT SHOULD CLEAR US
THURSDAY MORNING FOLLOWED BY MARGINALLY COOLER AND DRIER CONDITIONS.
UNTIL THEN THOUGH WE ARE FIRMLY BACK IN THE GRIP OF HOT AND HUMID
WEATHER.

NGM MOS NUMBERS ARE WARMER TODAY AND MONDAY THAN THE MAV DUE TO THE
NGM/S LOWER POPS. WILL LEAN TOWARD THESE HIGHER TEMPS. COMPROMISED
ON POPS THROUGH THE SHORT TERM.

AS FOR GFE/IFPS POPULATED THE USUAL WAY...FIRST 60 HOURS FROM
MESOETA FOR WINDS/TD/T. BASICALLY TWEAKED THESE AND THE REST WHILE
FILTERING THROUGH A DIURNAL CYCLE.

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

PRELIMINARY CCF:
LOZ 89/65 90/65 3121
JKL 88/68 89/68 2-21

.JKL...NONE.

GREIF

PREVIOUS DISCUSSIONS FOLLOW:

--------------------------------------------------------------------
920 PM EDT SAT AUG 10 2002

UPDATE ONLY TO REMOVE EARLY WORDING/POPS IN SW GROUP.  STRAY SHOWERS
ENTERED WAYNE COUNTY...THIS ACTIVITY SHOULD NOT LAST MUCH LONGER.
FORECAST ON TRACK.  CWA 01Z TEMPS AROUND 80.

UPDATE OUT SHORTLY.

.JKL...NONE.

OUDEMAN
--------------------------------------------------------------------
302 PM EDT SAT AUG 10 2002

...FORECAST ISSUES...
FORECAST CHALLENGE FOR THIS CYCLE REVOLVES AROUND PRECIP CHANCES FOR
TOMORROW AND IN THE EXTENDED.

...SHORT TERM...
RECENT SATELLITE PICS SHOWING LOTS OF CU OUT THERE THIS AFTERNOON AS
MOISTURE BEGINNING TO INCREASE ON THE HEELS OF RETURN FLOW FROM THE
GULF.  MODELS IN GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN ACROSS
NORTH AMERICA.  MODELS CONSISTENT FROM PREVIOUS RUN IN KNOCKING DOWN
RIDGE ACROSS THE EASTERN U.S. AS A SERIES OF WAVES MOVES ACROSS THE
NORTHERN TIER OF STATES.  AT THE SURFACE...HIGH PRESSURE WILL ANCHOR
ITSELF OFF THE SOUTHEAST COAST AND CONTINUE TO PUMP MOISTURE INTO
OUR AREA.  RECENT SAT AND RADAR PICS SHOWING TCU AND SOME STORMS
STARTING TO POP ACROSS TENNESSEE.  THIS ALONG A NICE DEWPOINT
GRADIENT AND WEAK TROF AXIS THAT HAS BEEN HANGING AROUND THE
SOUTHEAST FOR THE PAST SEVERAL DAYS.

FOR TONIGHT...WITH ACTIVITY STARTING TO POP TO OUR SOUTHWEST...WILL
CARRY A SLIGHT CHANCE OF PRECIP ACROSS THE SW ZONES.  EXPECT PATCHY
FOG TO ONCE AGAIN DEVELOP TONIGHT.  ON SUNDAY...ETA/AVN/META MODELS
TAKE WEAK TROF AXIS TO OUR SOUTH A MOVE IT A LITTLE FURTHER NORTH.
MODEL SOLUTIONS VARY ON AN EXACT LOCATION...BUT WITH INCREASING
INSTABILITY...NO CAP AND STEEP MID-LEVEL LAPSE RATES...SCATTERED
CONVECTION SHOULD HAVE LITTLE TROUBLE POPPING UP.  THUS...PLAN ON
CARRYING CHANCE POPS AT THIS TIME.  FOR MONDAY...WAA AT MID LEVELS
WILL BEGIN IN RESPONSE TO DEVELOPING CENTRAL PLAINS TROF.  THIS
SHOULD HELP STRENGTHEN THE CAP A LITTLE MORE AND SUPPRESS CONVECTION
A LITTLE BIT.  BUT FOR THE SAKE OF CONTINUITY STILL WILL CARRY
SLIGHT CHANCE POPS.  WILL LET LATER SHIFTS TAKE A LOOK AT THIS WITH
THE NEW MODEL RUNS.  FWC/MET/MAV NUMBERS ARE IN GOOD AGREEMENT AND A
BLEND WILL BE USED.

...EXTENDED...
MODELS SHOWING VERY GOOD CONTINUITY WITH UPPER LEVEL FLOW TAKING ON
A RIDGE WEST...CENTRAL U.S. TROF AND WEST ATLANTIC RIDGE THEN
FLATTENING OUT TO MORE OF A ZONAL PATTERN BY THE END OF NEXT WEEK.
SEVERAL WAVES WILL PINWHEEL THROUGH THE CENTRAL U.S. TROF THROUGH
THE PERIOD.  THE FIRST ONE WILL PASS BY ON WEDNESDAY.  AT THE
SURFACE...MODELS STILL BRING FRONTAL BOUNDARY THROUGH THE REGION.
HOWEVER...MUCH OF THE UPPER SUPPORT WILL HAVE ALREADY DEPARTED TO
THE NORTHEAST. HOWEVER...ENOUGH MOISTURE AND INSTABILITY WILL BE IN
PLACE TO KICK OFF SHOWERS AND THUNDERSTORMS.  FAST PACIFIC JET ROARS
INTO BACK SIDE OF CENTRAL TROF AND KICKS IT OFF TO THE EAST AND
BRINGS THE PATTERN BACK TO MORE OR LESS ZONAL.  AGREE WITH HPC
KEEPING NEXT FRONTAL BOUNDARY FURTHER NORTH AND WASHING IT OUT
BEFORE IT GETS HERE.  AS TO THE DETAILS TO THE FORECAST.  WILL
CONTINUE TO MENTION CHANCE OF SHOWERS/THUNDERSTORMS THROUGH THE
ENTIRE EXTENDED.  BEST CHANCES FOR PRECIP AGAIN WILL BE WITH THE
FRONTAL PASSAGE ON WEDNESDAY.  THU-SAT POPS WILL PRIMARILY BE
DIURNALLY DRIVEN IN NATURE.  NO REAL CHANGE IN TEMPERATURES WITH
LOWS IN THE MID TO UPPER 60S AND HIGHS OF 85 TO 90.

...PRELIM NUMBERS...

LOZ 64/87 64/87 0332
JKL 68/86 66/88 0332

.JKL...NONE.

JARVIS

=====================================================================
1035 AM EDT SAT AUG 10 2002

LATEST SFC AND 8H CHART THIS MORNING SHOWING A WARM FRONT/TROFF
LIFTING THRU THE NORTHERN PART OF THE CWA. 70 DEGREE DEWPOINTS
LURKING AS FAR NORTH AS BNA. TEMPS AND DEWPOINTS THIS MORNING RUNNING
A GOOD 5 DEGREES WARMER/HIGHER THAN YESTERDAY.

ZONES ON TARGET TODAY...HOWEVER BASED ON CO-OP REPORTS OF YESTERDAYS
HIGHS WILL RAISE TEMPS A CAT ACROSS THE CENTRAL ZONES...EXPECTING
HIGHS GENERALLY IN THE UPPER 80S TO AROUND 90. WILL HAVE TO WATCH
FOR A SLIGHT CHC OF A LATE AFTERNOON SHOWER NEAR THE TN BORDER WHICH
IS CLOSE TO A DEFORMATION ZONE/SFC TROFF AXIS ACROSS IN TN. FEEL
THIS WILL BE PRETTY ISOLATED THOUGH...SO WILL HOLD OFF ON
INTRODUCING INTO THE ZONES ATTM.

UPDATE OUT SHORTLY.

.JKL...NONE.

HALL