Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 290738
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
338 AM EDT FRI AUG 29 2014

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 338 AM EDT FRI AUG 29 2014

AN UPPER LEVEL RIDGE OF HIGH PRESSURE WAS CENTERED OVER THE
SOUTHEASTERN CONUS EARLY THIS MORNING AND EXTENDED NORTH AND
NORTHWEST INTO THE APPALACHIANS AND THE OH VALLEY REGION. OVER THE
MIDDLE OF THE COUNTRY...AN UPPER LEVEL TROUGH EXTENDED SOUTH THROUGH
THE PLAINS STATES IN BETWEEN THE RIDGE CENTERED ACROSS THE
SOUTHEASTERN CONUS AND ANOTHER RIDGE CENTERED TO THE SOUTHWEST OF
CALIFORNIA. AT THE SFC HIGH PRESSURE WAS CENTERED OVER THE GREAT
LAKES REGION. MEANWHILE...A BOUNDARY IS STALLED OUT FROM SOUTHEAST VA
SOUTH INTO THE APPALACHIANS AND EAST TN AND THEN NORTHWEST TO LOW
PRESSURE OVER THE PLAINS STATES. SOME PASSING CIRRUS AND MID LEVEL
CLOUDS ARE MOVING ACROSS THE REGION AT THIS POINT AROUND THE
RIDGE...ESPECIALLY THE FAR WEST AND THE NORTH. THIS HAS LEFT THE
CUMBERLAND VALLEY WITH THE LEAST CLOUD COVER.

DURING THE PERIOD...THE RIDGE IS EXPECTED TO REMAIN IN PLACE ACROSS
THE SOUTHEASTERN CONUS...THOUGH THE AXIS OF THE RIDGE WILL DEPART TO
THE EAST TODAY. THE SFC HIGH WILL MOVE EAST AS WELL. ALSO DURING THIS
TIME...THE TROUGH OVER THE MIDDLE OF THE COUNTRY IS EXPECTED TO LIFT
TOWARD THE GREAT LAKES WITH DEEP MOISTURE FROM THE GULF OF MEXICO
INCREASING LATE IN THE PERIOD ON SOUTHWEST FLOW ALOFT. THE FLOW
BETWEEN THE DEPARTED SFC HIGH AND THE SYSTEM MOVING INTO THE GREAT
LAKES WILL HAVE A BIT OF A DOWNSLOPE COMPONENT EARLY ON SATURDAY.

THROUGH SUNRISE AND TODAY...SOME AREAS OF VALLEY FOG HAVE FORMED OR
ARE EXPECTED TO FORM BEFORE SUNRISE...AND MIGHT BECOME DENSE IN A
COUPLE OF SPOTS. THE HARLAN AIRPORT KI35 HAS THE LOWEST VIS AT
PRESENT. HOWEVER...ANY DENSE FOG SHOULD NOT BECOME WIDESPREAD WITH
THE PASSING DEBRIS CLOUDS AND SOME MIXINESS WITH EAST TO SOUTHEAST
FLOW AROUND THE WESTERN EDGE OF THE SFC HIGH. OTHERWISE...THE STALLED
BOUNDARY WILL LIFT NORTH INTO THE REGION TODAY AS A WARM FRONT AND
COMBINE WITH A WEAK APPROACHING DISTURBANCE IN SOUTHWEST FLOW AND
DAYTIME HEATING TO YIELD GENERALLY ISOLATED TO POSSIBLY SCATTERED
SHRA AND TSRA DURING THE AFTERNOON AND EVENING HOURS.

THIS BOUNDARY WILL EXIT TO THE NORTH AND EAST TONIGHT AND INTO EARLY
ON SATURDAY...LEAVING THE REGION IN THE WARM SECTOR. A WARM AIRMASS
WILL REMAIN IN PLACE AND MOISTURE WILL INCREASE IN ALL LEVELS LATE IN
THE PERIOD AS PW IS ANTICIPATED TO RISE TO AROUND 1.75 INCHES OR
MORE IN MOST PLACES LATE. HOWEVER...FORCING FOR SAT REMAINS VERY
LIMITED AND THE 0Z ECMWF AND 0Z GFS ACTUALLY HAVE SFC DEWPOINTS
DECREASING FOR A WHILE ON SATURDAY POSSIBLY FROM THE DOWNSLOPE LOW
LEVEL COMPONENT TO THE WINDS. IN ADDITION...THERE IS ALSO A MID LEVEL
CAP FOR MUCH OF THE DAY AS WELL. ANY CONVECTION ON SAT SHOULD BE LATE
IN THE DAY OR EARLY IN THE EVENING...AND THE BEST CHANCES APPEAR TO
BE ACROSS THE SOUTHWEST AND WEST. TEMPERATURES ON SAT SHOULD APPROACH
OR REACH 90 IN MANY LOCATIONS.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 238 AM EDT FRI AUG 29 2014

MODELS HAVE BEEN FAIRLY CONSISTENT ON ADVERTISING A FAIRLY SHARP
TROUGH PUSHING ACROSS THE OHIO RIVER VALLEY LATE SATURDAY NIGHT INTO
SUNDAY MORNING. THUS...CONFIDENCE IS FAIRLY HIGH WE WILL SEE BETTER
PRECIPITATION COVERAGE AROUND THIS PERIOD. WE MAY SEE A LULL FROM
DIURNALLY DRIVEN CONVECTION ON SATURDAY THROUGH THE FIRST PART OF
SATURDAY NIGHT. HOWEVER...SHOWERS AND STORMS WILL DEVELOP AND PUSH
ACROSS THE AREA BY DAYBREAK. PW`S WILL CLIMB TO 1.8 TO 2 INCHES
DURING THIS PERIOD..YIELDING THE THREAT FOR LOCALLY HEAVY RAINFALL
AS THESE VALUES ARE NEAR THE 99TH PERCENTILE FOR LATE AUGUST.
FORTUNATELY...STORM MOTION SHOULD BE SUFFICIENT TO PREVENT SLOW
MOVING STORMS. MAIN CONCERN WILL REVOLVE AROUND ANY TRAINING STORMS
WHICH MAY OCCUR. REGARDLESS...STORM WILL BE HEAVY RAINERS WITH GOOD
POTENTIAL FOR PONDING ON ROADWAYS.

SHORTWAVE TROUGH WILL BE ON THE WAY OUT BY LATE SUNDAY WITH
PRECIPITATION CHANCES DECREASING. HOWEVER...STRONG RIDGING WILL
DEVELOP OVER THE DEEP SOUTH...WITH EASTERN KENTUCKY RESIDING ON THE
NORTH EDGE OF THIS HIGH PRESSURE DOME. THIS WILL KEEP THE AREA
SUSCEPTIBLE TO WEAK SHORTWAVES AS THEY PROGRESS EASTWARD ALONG THE
NORTHERN PERIPHERALS OF THIS HIGH PRESSURE AREA THROUGH THE WEEK.
THUS...IT LOOKS LIKE THE WEATHER MAY STAY UNSETTLED WELL INTO NEXT
WEEK AND PERHAPS BEYOND. THIS WARRANTS AT LEAST CHANCE POPS ALL THE
WAY THROUGH THE END OF THE PERIOD. DOES NOT APPEAR WE WILL SEE ANY
FORCING QUITE AS STRONG AS THIS WEEKEND...BUT ANY WEAK SHORTWAVE
THIS TIME OF YEAR...COMBINED WITH DAYTIME INSTABILITY WOULD BE
ENOUGH TO GENERATE ISOLATED TO SCATTERED STORMS. GIVEN THE TENDENCY
FOR BETTER COVERAGE DURING THE AFTERNOONS/EVENINGS THIS TIME OF
YEAR...PLAN TO GO WITH A DIURNAL TREND WITH POPS. TEMPERATURES WILL
LIKELY STAY NEAR OR JUST ABOVE NORMAL THROUGH THE PERIOD AS HEAT AND
HUMIDITY CONTINUE THROUGH THE NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 158 AM EDT FRI AUG 29 2014

IFR OR WORSE FOG IS EXPECTED TO DEVELOP LATE TONIGHT NEAR VALLEYS OF
LARGE STREAMS. THE FOG WILL DISSIPATE BY AROUND 13Z FRIDAY...LEAVING
PREVAILING VFR. AT THE TAF SITES...MAINLY MVFR FOG IS EXPECTED FOR A
FEW HOURS BETWEEN ABOUT 8Z AND 13Z. THIS MIGHT DROP INTO THE IFR
RANGE AT SJS FOR A COUPLE OF HOURS AROUND 11Z. OTHERWISE...ONCE THE
FOG DISSIPATES... ISOLATED THUNDERSTORMS ARE EXPECTED AFTER 16Z...AS
A BOUNDARY CURRENTLY STALLED OUT TO OUR SOUTH RETURNS NORTH AS WARM
FRONT. VIS AND OR CIGS COULD DROP BRIEFLY TO IFR OR LOWER IN ANY
LOCATION THAT IS DIRECTLY AFFECTED BY ANY TSRA.


&&

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

$$

SHORT TERM...JP
LONG TERM...KAS
AVIATION...JP



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