000
FXUS63 KJKL 240031 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
831 PM EDT WED JUL 23 2014

.UPDATE...
ISSUED AT 831 PM EDT WED JUL 23 2014

CLUSTERS OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE PAST
FEW HOURS AND HAVE SLOWLY SAGGED EAST WITH TIME. HEAVY RAINFALL HAS
BEEN THE BIGGEST CONCERN WITH THESE DUE TO THE SLOW MOVEMENT OF THE
SYSTEM AND EMBEDDED TRAINING STORMS. HAVE UPDATED THE POPS
ACCORDINGLY. EXPECT THIS CONVECTION TO GRADUALLY WEAKEN AS IT HEADS
FURTHER SOUTHEAST...WHERE INSTABILITY HAS NOT MADE MUCH OF A RECOVERY
AFTER CONVECTION FROM EARLY TODAY HAD MOVED THROUGH THE AREA. THIS
IS SUPPORTED BY THE LATEST HRRR...WHICH HAS STRUGGLED WITH CAPTURING
THIS SYSTEM AS IT EVOLVED...BUT IN RECENT RUNS APPEARS MORE
REASONABLE.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 505 PM EDT WED JUL 23 2014

BROAD CYCLONIC FLOW ALOFT WILL SHARPEN UP A BIT OVER THE NEXT 12 TO
18 HOURS. OTHER THAN A MINOR RIPPLE IN THE FLOW THURSDAY NIGHT...
SHORT WAVE RIDGING WILL BEGIN BUILDING INTO THE REGION THURSDAY.
COLD FRONTAL BOUNDARY STILL JUST NORTH OF THE OHIO RIVER SLIDING
SOUTHWARD AT A VERY SLOW PACE...BUT SHOULD GET A HELPFUL KICK START
THROUGH THE OVERNIGHT PERIOD. BOUNDARY SHOULD PUSH INTO EASTERN
KENTUCKY LATE TONIGHT AND BE OUT OF OUR FORECAST AREA BY MID MORNING
TO NOON ON THURSDAY AS CANADIAN HIGH PRESSURE BUILDS IN BEHIND. UNTIL
THEN SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST. THUS FAR
THERE HAS BEEN NO REAL ORGANIZATION TO CONVECTION EXCEPT ALONG
RESIDUAL OUTFLOW BOUNDARIES. BASED ON RADAR AND SATELLITE TRENDS
EXPECT A LULL IN ACTIVITY THROUGH THE LATE AFTERNOON. BUT EXPECT
SHOWERS AND THUNDERSTORMS WILL REDEVELOP THIS EVENING AND HAVE
REFLECTED THIS IN THE GRIDS. OTHERWISE NUDGED GRIDS TO LATEST BLEND
OF MODELS...ESPECIALLY TEMPS. GUSTY WINDS AND HEAVY RAIN WILL REMAIN
A THREAT UNTIL LATER TONIGHT AS REFLECTED IN THE HWO.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 257 PM EDT WED JUL 23 2014

HE LONG TERM PORTION OF THE FORECAST WILL FEATURE A MEAN TROUGH
OVER THE EASTERN PART OF THE COUNTRY WITH RIDGING OVER THE WEST.
THIS WILL RESULT IN SIGNIFICANTLY COOLER THAN NORMAL CONDITIONS FOR
OUR AREA NEXT WEEK AS THE WESTERN RIDGE AMPLIFIES AND THE EASTERN
TROUGH DEEPENS.

SURFACE HIGH PRESSURE WILL BUILD INTO THE OH VALLEY ON FRIDAY
BRINGING FAIR MILD WEATHER TO END THE WORK WEEK. HOWEVER RAIN
CHANCES WILL RETURN AS A WARM FRONT APPROACHES FRIDAY NIGHT INTO
SATURDAY. THE REMAINS OF A POSSIBLE MCS MAY APPROACH THE NW PART OF
THE FORECAST AREA BY EARLY SATURDAY MORNING AND WILL INTRODUCE
SLIGHT CHANCE RAIN PROBABILITIES IN THE NW PART OF THE FORECAST AREA
AFTER 06Z ON SATURDAY. THE WEEKEND LOOKS TO BE UNSETTLED AS THE
REMAINS OF THE RETURNING WARM FRONT BECOME STATIONARY AND LINGER IN
THE AREA...AND THEN A COLD FRONT APPROACHES ON SUNDAY. THIS WILL
REQUIRE SHOWER AND THUNDERSTORM CHANCES IN THE FORECAST THROUGH THE
WEEKEND.

BY LATE IN THE WEEKEND THE OVERALL UPPER AIR FLOW WILL BEGIN A
SIGNIFICANT AMPLIFICATION WITH MAJOR DEEPENING OF THE EASTERN NORTH
AMERICAN TROUGH AND AMPLIFICATION OF THE WESTERN RIDGE. THIS PROCESS
WILL BEGIN AS AN UPPER LOW MOVES FROM SOUTH CENTRAL CANADA ON
SATURDAY INTO THE GREAT LAKES REGION BY SUNDAY NIGHT. AT THE SURFACE
THIS WILL RESULT IN A SIGNIFICANT COLD FRONT DRIVING SOUTH ACROSS KY
LATE IN THE WEEKEND. WHILE EXACT TIMING OF THE FRONTAL PASSAGE IS
STILL UNCERTAIN...IT APPEARS AT THIS TIME THE FRONT WILL MOVE SOUTH
OF THE AREA BY MONDAY MORNING. THE BEST CHANCE FOR STRONG STORMS
DURING THE COMING WEEKEND LOOKS TO BE FROM SUNDAY INTO SUNDAY
EVENING WITH THE APPROACH OF THE COLD FRONT FROM THE NORTHWEST.

WITH THE UNUSUALLY DEEP TROUGH IN THE EAST...NOTED BY WPC TO HAVE
HEIGHTS APPROACHING 3 STANDARD DEVIATIONS BELOW NORMAL IN THE OH
VALLEY AND APPALACHIANS...MUCH COOLER THAN NORMAL CONDITIONS WILL
PREVAIL INTO THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 831 PM EDT WED JUL 23 2014

NUMEROUS SHOWERS AND THUNDERSTORMS WILL SAG SOUTHEAST ACROSS THE AREA
THROUGH 03Z. EXPECT MVFR CONDITIONS WITH TEMPORARY IFR OR WORSE
CONDITIONS AT TIMES FROM ANY DIRECT HIT FROM A THUNDERSTORM. THE
THREAT OF CONVECTION WILL LINGER THROUGH MID-DAY THURSDAY AS A COLD
FRONT SLOWLY PUSHES THROUGH THE AREA. CONDITIONS WILL IMPROVE FROM
NORTHWEST TO SOUTHEAST BY LATE MORNING AND BEYOND AS HIGH PRESSURE
MOVES IN FROM THE NORTHWEST.

&&

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

$$

UPDATE...GEOGERIAN
SHORT TERM...RAY
LONG TERM...SBH
AVIATION...GEOGERIAN