617
FXUS63 KJKL 042251
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
651 PM EDT SAT JUL 4 2009
SHORT TERM
/TONIGHT THROUGH SUNDAY NIGHT/
LIGHT RAIN FROM REMANTS OF MCS BEGINNING TO MOVE INTO THE NORTHERN
PART OF THE FORECAST AREA. EXTENSIVE CLOUDINESS FROM THE MCS HAS
REMAINED ACROSS THE FORECAST AREA TODAY. THIS IN ADDITION TO LOW
LEVEL DIVERGENCE ACROSS EASTERN KY HAS LIMITED THE DEVELOPMENT OF
CONVECTION IN OUR AREA. THUNDERSTORMS HAVE CONTINUED TO DEVELOP IN
WEST KY ON THE SOUTHERN EDGE OF OLD MCS IN AREA WITH GREATER
INSTABILITY AND LOW LEVEL CONVERGENCE. FOR THE REST OF THE AFTERNOON
EXPECT ONLY LIGHT SHOWERS...WITH NO THUNDER IN THE NORTHERN PART OF
FORECAST AREA. MODELS ARE STILL CONSISTENT IN MOVING THE SURFACE LOW
ACROSS KY TONIGHT AND EARLY SUNDAY...AS SHORT WAVE MID LEVEL TROF
MOVES EAST. THIS WILL INCREASE LIFT ACROSS E KY OVERNIGHT WITH
WIDESPREAD SHOWERS AND SOME THUNDERSTORMS MOVING ACROSS OUR AREA.
WILL GO WITH CATEGORICAL POPS FOR TONIGHT ACROSS THE ENTIRE AREA. THE
GFS IS SLOWEST WITH MOVEMENT OF LOW ACROSS THE STATE...WITH LOW STILL
OVER SC KY AT 18Z SUNDAY. PREFER THE 12Z NAM WHICH IS SUPPORTED BY
THE SREF WITH AN EXIT 6 TO 9 HOURS QUICKER SUNDAY MORNING. EVEN WITH THE
QUICKER MOVEMENT FOLLOWED HERE WILL STILL NEED TO INCREASE
PROBABILITY OF PRECIPITATION FOR SUNDAY TO RANGE FROM LIKELY IN THE
NORTHWEST TO CATEGORICAL IN THE SOUTHEAST. SEVERE THREAT LOOKS TO BE
LIMITED AT THIS TIME...WITH BEST CHANCE IN W KY THIS EVENING AND OVER
TN ON SUNDAY PER THE LATEST SPC OUTLOOKS. A FEW STRONG STORMS ARE
STILL POSSIBLE...ESPECIALLY OVER SW PART OF FORECAST AREA TONIGHT.
LONG TERM
/MONDAY THROUGH SATURDAY/
INITIALLY AN UPPER LEVEL RIDGE IS EXPECTED TO EXTEND FROM MEXICO
NORTH THROUGH THE ROCKIES WITH A TROUGH FROM THE ST LAWRENCE VALLEY
DOWN INTO THE EASTERN CONUS. ON AVERAGE...HEIGHT RISES ARE EXPECTED
ACROSS THE AREA THROUGH EARLY FRIDAY AS THE INITIAL TROUGH LIFTS OUT
OF THE EASTERN CONUS AND RIDGING OVER THE SOUTHWESTERN US TOWARD THE
GREAT LAKES AND OH VALLEY. HOWEVER...A SHORTWAVE WILL MOVE AROUND THE
RIDGE ACROSS THE NORTHERN CONUS AND INTO SOUTHERN CANADA. AT THE SAME
TIME...THE RIDGE IS EXPECTED TO BUILD NORTH THROUGH THE ROCKIES
LEADING TO A MORE AMPLIFIED PATTERN BY THE END OF THE PERIOD...WITH A
RETURN OF A NORTHEASTERN OR EASTERN CONUS TROUGH. NW OR WNW FLOW
ALOFT IS EXPECTED THROUGH ABOUT THU...BUT ATTM IS NOT EXPECTED TO
LEAD TO ANYTHING MORE THAN POSSIBLE PERIODIC INCREASES IN CLOUDS. AT
THE SFC...HIGH PRESSURE WILL BUILD INTO THE OH VALLEY FROM THE PLAINS
EARLY IN THE PERIOD WITH THE HIGH SHIFTING EAST ACROSS THE GREAT
LAKES AND OH VALLEY AT MIDWEEK...BEFORE REACHING THE EASTERN
SEABOARD ON THU AND FRI. A COLD FRONT ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE SHOULD SEND A COLD FRONT TO THE OH RIVER BY LATE
FRI AND EARLY SAT...WITH THE BOUNDARY REACHING THE CWA AT THE END OF
THE PERIOD.
MOST OF THE PERIOD WILL FEATURE A WARMING TREND AS MAX TEMPS CLIMB
FROM THE LOWER 80S...BEFORE APPROACHING OR EXCEEDING THE 90 DEGREE
MARK BY THU AND FRI. ONCE THE HIGH SHIFTS EAST OF THE AREA DEWPOINTS
AND HUMIDITY WILL INCREASE WITH DEWPOINTS EXPECTED TO REACH THE UPPER
60S TO AROUND 70 BY FRI. HOWEVER...NORTHERLY TO NORTHEASTERLY FLOW
AROUND THE HIGH SHOULD LEAD TO MORE COMFORTABLE DEWPOINTS MON THROUGH
WED. AT LEAST SMALL TO PERHAPS MODERATE RIDGE/VALLEY TEMP SPLITS MAY
OCCUR WITH VALLEY TEMPS REACHING THE UPPER OR PERHAPS EVEN THE MID
50S ON MON AND TUE NIGHTS...WHILE RIDGETOPS REMAIN IN THE 60S.
AS FOR POPS UNDER THE INFLUENCE OF SFC AND UPPER LEVEL RIDGING...DRY
WEATHER IS EXPECTED THROUGH FRI...WITH PRECIP CHANCES INCREASING LATE
IN THE PERIOD AS THE INCREASINGLY SHEARED BOUNDARY APPROACHES THE
REGION AND SHOULD INTERACT WITH ABUNDANT MOISTURE TO PRODUCE AT LEAST
ISOLATED CONVECTION.
AVIATION.../00Z TO 24Z/
UPDATED
VFR CONDITIONS TO BEGIN THIS FORECAST WITH LIGHT SHOWERS MOVING
ACROSS THE NORTHERN PART OF THE FORECAST AREA. CONDITIONS WILL
DETERIORATE AFTER SUNSET AS LOW PRESSURE APPROACHES FROM THE WEST.
THE LOW WILL MOVE EAST ACROSS KENTUCKY TONIGHT AND BE EAST OF KY
AFTER 15Z SUNDAY. EXPECT SHOWERS AND THUNDERSTORMS TO MOVE ACROSS THE
AREA BETWEEN 03Z AND 09Z WITH LOWERING CEILINGS AND VISIBILITIES. LOW
CLOUD AND FOG TO DEVELOP IN THE WAKE OF THE RAIN WITH IFR TO MVFR
CONDITIONS PERSISTING INTO SUNDAY AFTERNOON. LINGERING SHRA EVEN INTO
THE EVENING BUT ENDING OVERNIGHT SUNDAY NIGHT...WILL INCLUDE VCSH IN
THE LATTER PORTION OF THE FCST.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...SBH
LONG TERM....JP
AVIATION...DUSTY
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