Severe Thunderstorm Warning 120, NWS Jackson, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
259 AM EDT SUN MAY 1 2011

.SHORT TERM.../TODAY THROUGH TUESDAY/...UPDATED

LATEST SURFACE ANALYSIS THIS MORNING HAS AN OCCLUDING STORM SYSTEM
OVER THE NORTHERN PLAINS...WITH A WEAK FRONTAL BOUNDARY NORTH-SOUTH
ORIENTED FROM CENTRAL WISCONSIN...TO SOUTHERN MISSOURI. A WEAK
MID LEVEL IMPULSE HAS TRIGGERED NUMEROUS SHOWERS AND THUNDERSTORMS
ACROSS THE MID MISSISSIPPI RIVER VALLEY...STRETCHING INTO THE WESTERN
BASIN OF THE OHIO RIVER OVERNIGHT. CLOSER TO HOME...EASTERN KENTUCKY
IS QUIET UP TO THIS POINT WITH ONLY SOME HIGH CLOUDS WORKING IN FROM
THE WEST. DRIER AIR HAS VIRTUALLY ERODED ANYTHING TRYING TO PUSH INTO
OUR NECK OF THE WOODS. THE FRONTAL BOUNDARY TO OUR WEST WILL BE THE
FOCUS OF THE FORECAST INTO THE UPCOMING WEEK WITH PERIODIC CHANCES
FOR SHOWERS AND THUNDERSTORMS THE MAIN FORECAST ISSUE.

AS FAR AS THIS MORNING GOES...BASED ON CURRENT RADAR TRENDS...IT
APPEARS MOST OF THE SHOWER AND THUNDERSTORM ACTIVITY SHOULD SAY
MAINLY ALONG AND NORTH OF I-64 THROUGH THE MORNING HOURS.
THUS...GOING TO DECREASE POPS TO VIRTUALLY NOTHING ACROSS THE
SOUTHERN TWO THIRDS OF THE AREA. WILL KEEPS POPS GOING THROUGH A GOOD
CHUNK OF THE DAY ACROSS THE NORTH...WITH PLENTY OF MOISTURE
CONVERGENCE LOCATED CLOSER TO THE FRONTAL BOUNDARY.

BY THIS EVENING...IT SEEMS THAT MODELS ARE KEEPING THE PRECIPITATION
OUT WEST THROUGH MUCH OF TONIGHT. SEEMS TO BE GOOD AGREEMENT ON THIS
IDEA...SO WILL BACK OFF POPS CONSIDERABLY FOR TONIGHT. THE FRONTAL
BOUNDARY WILL LIKELY INCH EASTWARD THROUGH MONDAY AND MONDAY NIGHT.
AS THIS HAPPENS...PRECIPITATION CHANCES WILL AGAIN INCREASE FROM
NORTHWEST TO SOUTHEAST. THE SOUTHEASTERN ZONES COULD VERY WELL STAY
DRY THROUGH MONDAY EVENING.

MONDAY NIGHT INTO TUESDAY...A STRONG MID LEVEL WAVE WILL PUSH INTO
THE OHIO AND TENNESSEE VALLEYS...HELPING TO FINALLY GIVE THE FRONT A
BETTER PUSH TO THE EAST. THIS IS THE MOST LIKELY TIME FOR WIDESPREAD
PRECIPITATION ACROSS ALL OF EAST KENTUCKY WITH GOOD DYNAMICS AND
MOISTURE ALONG THE ADVANCING FRONTAL BOUNDARY. AN AREA OF LOW
PRESSURE WILL ALSO DEVELOP ALONG THE FRONT AND TRACK NORTHWARD FROM
NORTHEAST TENNESSEE INTO NEW ENGLAND. THIS IS A FAVORABLE TRACK FOR
WIDESPREAD LIGHT TO MODERATE RAIN ACROSS EAST KENTUCKY.

GIVEN THE ACTIVE WEATHER...THERE IS POTENTIAL AREAS NORTH AND WEST
COULD RECEIVE ANOTHER 1 TO 2 INCHES OF RAIN FROM TODAY THROUGH
TUESDAY EVENING...WHILE AREAS TO THE SOUTHEAST WILL LIKELY END UP
WITH MUCH LESS. AT THIS POINT...RAINFALL APPEARS TO BE SPREAD OUT
OVER THE ENTIRE PERIOD WITH SUBSTANTIAL BREAKS IN THE RAINFALL...SO
NO FLOOD WATCH IS ANTICIPATED AT THIS POINT.

QUITE A BIG SPREAD IN THE MAV AND MET GUIDANCE OVER THE NEXT FEW DAYS
MAINLY DUE TO CLOUD COVER AND PRECIPITATION CHANCES IN THE TWO
MODELS. HOWEVER...GIVEN A DRIER FORECAST FOR TODAY THROUGH
TOMORROW...OPTING TO GO WITH THE MILDER MAV GUIDANCE...NUDGED
SLIGHTLY TOWARD THE MET GUIDANCE. THE MET GUIDANCE SIMPLY SEEMS TOO
COLD GIVEN THE MILD AIRMASS IN PLACE. AS THE FRONT PUSHES THROUGH ON
TUESDAY...MUCH COOLER CONDITIONS WILL RETURN.

.LONG TERM.../TUESDAY NIGHT THROUGH SATURDAY/...UPDATED

THE MODELS START OFF IN PRETTY GOOD AGREEMENT AS THEY ARE BOTH
TRYING TO FINALLY MOVING THE UPPER TROUGH OFF TO THE EAST. BOTH THE
GFS AND ECMWF KEEP QUITE A BIT OF WRAP AROUND SHOWERS IN THE AREA
UNTIL THE UPPER TROUGH ACTUALLY MOVES TO THE EAST OF THE AREA ON
WEDNESDAY NIGHT. HIGH PRESSURE MOVES INTO THE AREA ON THURSDAY UNTIL
THE NEXT SHORT WAVE PUSHES ANOTHER FRONT INTO THE AREA ON FRIDAY.
THE MODELS WERE TRENDING A BIT SLOWER WITH THE FRONT AND AS SUCH
MADE A 6 TO 12 HOUR ADJUSTMENT TO THE ONSET OF PRECIPITATION. THE 12 GMT
ECMWF HELD ONTO THE PRECIPITATION A LITTLE LONGER THAN THE GFS AND
SO I TRIED TO BLEND THE TWO AND MAY MAKE A SLIGHT ADJUSTMENT WHEN I
SEE THE NEW 00 GMT ECMWF. FOR TEMPS NUDGED THE FORECAST TOWARD THE
CONSENSUS MOS THROUGH THURSDAY AND THEN ACTUALLY HAD TO BLEND IN
SOME RAW MODEL OUTPUT AT THE END OF THE PERIOD TO COME UP WITH A
REASONABLE FORECAST. CONFIDENCE IS FAIRLY GOOD FOR THE GENERAL
PATTERN AND SEQUENCE HOWEVER CONFIDENCE IS A BIT LOW WITH THE ACTUAL
TIMING OF THESE SHORT WAVES. EXPECT THAT THE TIMING WILL BE CHANGING
WITH FUTURE MODEL OUTPUT.

&&

.AVIATION.../06Z TO 06Z/

THE PERIOD WILL START VFR AND DRY. A COLD FRONT APPROACHING FROM THE
NW WILL BRING INCREASING CLOUDS...WITH CEILINGS DEVELOPING AND
LOWERING DURING THE EARLY MORNING HOURS. THE MODELS ARE NOT IN VERY
GOOD AGREEMENT WITH THE TIMING OF ANY PRECIPITATION MOVING INTO
EASTERN KENTUCKY TODAY. ONE THING THEY ARE IN AGREEMENT WITH IS THAT
WHATEVER MOVES ACROSS...IT WILL NOT BE STRONG ENOUGH TO BE ABLE TO
LOWER THE CIGS TO MVFR LEVELS. THERE IS A LOT OF DRY AIR IN THE
LOWER LAYERS THAT NEEDS TO BET MOISTENED UP. THE GFS IS QUICKER AND
WEAKER WITH A SHORT WAVE MOVING ACROSS THE AREA. THE NAM IS
SLOWER...BUT SHOWS CLOUDS DROPPING TO LOWER LEVELS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...NONE.

&&

SHORT TERM...KAS
LONG TERM...JJ
AVIATION...JJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON KY
420 AM EDT SUN MAY 1 2011

KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120-021200-
FLEMING-MONTGOMERY-BATH-ROWAN-ESTILL-POWELL-MENIFEE-ROCKCASTLE-
JACKSON-PULASKI-LAUREL-WAYNE-MCCREARY-WHITLEY-KNOX-BELL-HARLAN-
ELLIOTT-MORGAN-JOHNSON-WOLFE-MAGOFFIN-FLOYD-LEE-BREATHITT-KNOTT-
OWSLEY-PERRY-CLAY-LESLIE-LETCHER-MARTIN-PIKE-
420 AM EDT SUN MAY 1 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN KENTUCKY.

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS ARE POSSIBLE NORTH OF THE HAL RODGERS PARKWAY TODAY.
THUNDERSTORMS ARE POSSIBLE ACROSS ALL OF EAST KENTUCKY TONIGHT.

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

THUNDERSTORMS ARE POSSIBLE FROM MONDAY...THROUGH MONDAY NIGHT.
THUNDERSTORMS REMAIN POSSIBLE NEAR THE VIRGINIA BORDER ON TUESDAY.

THUNDERSTORMS ARE POSSIBLE AGAIN ON FRIDAY AND FRIDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

KAS