Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 060207 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
1007 PM EDT THU MAY 5 2016

.UPDATE...
ISSUED AT 1007 PM EDT THU MAY 5 2016

RECENT RADAR TRENDS INDICATE THAT THE RAIN SHOWERS WILL CONTINUE
TO EXPERIENCE OVERNIGHT WILL NOT SPREAD QUITE AS FAR WESTWARD...OR
BE QUITE AS WIDESPREAD...AS PREVIOUSLY FORECAST. THEREFORE...THE
HOURLY FORECAST GRIDS THROUGH 12Z FRIDAY HAVE BEEN UPDATED TO
REFLECT THESE LATEST TRENDS. AN UPDATED ZONE FORECAST TEXT
PRODUCT HAS BEEN ISSUED AS WELL. THE REST OF THE FORECAST IS IN
GOOD SHAPE.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 325 PM EDT THU MAY 5 2016

WV SAT AND HRRR HAS SUGGESTED THAT THE UPPER LEVEL CLOSED LOW HAS
PROGRESSED SOUTHEAST INTO WESTERN NC AND NW SC. OVERALL THE MESO
MODELS AND MORE SYNOPTIC MODELS HAVE HAD A DECENT HANDLE ON THIS
PROGRESSION. WE CONTINUE TO HAVE SOME SHOWERS THAT HAVE DEVELOPED
ACROSS THE SOUTH AND SW PORTIONS OF THE CWA. THIS HAS BEEN DUE TO
THE STEEPER LOW LEVEL LAPSE RATES...AS WE HAVE SEEN BREAKS IN THE
CLOUDS. THESE LAPSE RATES ARE COMBINING WITH THE ALREADY
REASONABLY STEEP MID LEVEL LAPSE RATES. OVERALL COVERAGE HAS BEEN
SCATTERED WITH BETTER COVERAGE TO THE SOUTH AND EAST. RIGHT NOW
MODELS DO WANT TO BRING ADDITIONAL SHOWERS IN THE FAR EAST THIS
EVENING AND TONIGHT...HOWEVER BIGGEST QUESTION WOULD BE HOW MUCH
COVERAGE DO WE SEE. RIGHT NOW OPTED TO LOWER POPS GIVEN SOME OF
THE UNCERTAINTY. THIS UNCERTAINTY COMES WHEN LOOKING UPSTREAM
RADAR COVERAGE IS QUITE LOW COMPARED TO WHAT MAY HAVE BEEN
PREVIOUSLY THOUGHT AND CAMS ARE NOT HITTING IT TOO HARD EITHER.
THE OTHER QUESTION WOULD BE HOW MUCH CLOUD COVER DO WE SEE
TONIGHT...RIGHT NOW KEEP CLOUD COVER HIGHER IN THE EAST GIVEN THE
BETTER SHOWER COVERAGE. ALSO COULD HAVE IMPLICATIONS ON TEMPS AND
FOG POTENTIAL. RIGHT NOW WILL ADD SOME PATCHY DEEPER VALLEY FOG
AND JUST MINOR TEMP SPLIT GIVEN THE CLOUD UNCERTAINTY.

THIS UPPER LOW IS FAIRLY SLOW TO MOVE EAST...AS A OMEGA BLOCK
PATTERN SETS UP ACROSS THE CENTRAL PART OF THE CONUS. THEREFORE
SURFACE HIGH PRESSURE WILL BE SLOW TO BUILD NORTHEAST FROM THE
GULF. THAT SAID THERE WAS A NEED FOR SHOWERS IN THE FAR EAST AND
SOUTHEAST FOR FRIDAY GIVEN THE SLOW PROGRESS OF VERTICALLY STACKED
LOW AND CONTINUED PVA/SHORTWAVES DIVING SOUTH. NOW FRIDAY NIGHT
HEIGHTS WILL CONTINUE TO RISE AS UPPER LOW/OMEGA BLOCK BREAK DOWN
AND PROGRESS EAST. THERE IS A WEAK SURFACE TROUGH OR WAVE MAY
BRING SOME SLIGHT CHANCE SHOWERS TO THE FAR NORTH OVERNIGHT.
OTHERWISE MOST SPOTS SHOULD DRY OUT AT THIS POINT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 353 PM EDT THU MAY 5 2016

MODELS ARE IN REASONABLY GOOD AGREEMENT WITH AN OMEGA BLOCK PATTERN
DEAMPLIFYING OVER THE WEEKEND AND EVOLVING TO MORE OR LESS A SPLIT
FLOW PATTERN NEXT WEEK. THE CURRENT UPPER LEVEL SYSTEM MEANDERING OF
THE APPALACHIANS AND THE SOUTHEAST IS EXPECTED TO SHIFT OFF THE
EASTERN SEABOARD. AT THE SAME TIME...AN UPPER LEVEL LOW WILL MOVE
FROM THE HUDSON AND JAMES BAY REGION INTO ONTARIO AND QUEBEC AND
THEN INTO THE CANADIAN OVER THE WEEKEND AND INTO EARLY NEXT WEEK. A
SHORTWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE GREAT LAKES REGION
EARLY IN THE PERIOD AND INTO THE NORTHEASTERN CONUS BY THE END OF
THE WEEKEND. THIS WILL SEND A COLD FRONT INTO THE OHIO VALLEY AND
APPALACHIAN REGION FROM LATE SATURDAY INTO SATURDAY NIGHT...WITH THE
BOUNDARY STALLING OUT LATE IN THE WEEKEND ACROSS THE OHIO OR
TENNESSEE VALLEY. THE MODEL CONSENSUS IS FOR A SMALL CHANCE OF
CONVECTION ON ISENTROPIC LIFT EARLY IN THE PERIOD ON SATURDAY. A
LULL IN ACTIVITY IS POSSIBLE FROM MIDDAY INTO THE AFTERNOON ON
SATURDAY...WITH MORE ORGANIZED CONVECTION LIKELY SATURDAY EVENING
INTO SATURDAY NIGHT. CHANCES FOR CONVECTION APPEAR TO LESSEN ON
SUNDAY AS THE SHORTWAVE TROUGH DEPARTS TO THE EAST AND NORTHEAST.

AN AREA OF SFC LOW PRESSURE MEANWHILE WILL BEGIN TO DEVELOP OVER THE
WEEKEND IN THE LEE OF THE ROCKIES AHEAD OF THE SECOND UPPER LEVEL
LOW MEANDERING FROM THE SOUTHWESTERN CONUS INTO THE ROCKIES OVER THE
WEEKEND AND EVENTUALLY EJECTING INTO THE PLAINS. IN RESPONSE TO THE
DEVELOPING LOW AND HEIGHT RISES OVER THE SOUTHEASTERN CONUS...THE
STATIONARY FRONT SHOULD RETURN NORTH AS A WARM FRONT MONDAY INTO
MONDAY NIGHT. EVEN AS THE REGION GETS INTO THE WARM SECTOR
CONVECTION CANNOT BE RULED OUT AT ANY POINT ON MONDAY. THE SFC LOW
PRESSURE SYSTEM SHOULD GRADUALLY TRACK FROM THE PLAINS TOWARD THE
GREAT LAKES REGION AT MIDWEEK AND THEN EVENTUALLY INTO THE
NORTHEASTERN CONUS. MODEL AGREEMENT FROM RUN TO RUN AND MODEL TO
MODEL IN THESE DETAILS DIMINISHES GREATLY BY TUESDAY AND TUESDAY
NIGHT AND ALSO CONFIDENCE IN ANY DETAILS. HOWEVER...THE OVERALL
MODEL BLEND AND CONSENSUS APPEARS TO BE FOR ANOTHER PEAK IN
CONVECTION CHANCES FROM LATE MONDAY NIGHT OR TUESDAY INTO THE DAY ON
WEDNESDAY AS SEVERAL SHORTWAVES SHOULD MOVE THROUGH THE OHIO VALLEY
AND GREAT LAKES REGION. LOCALLY HEAVY RAIN COULD BECOME A CONCERN
IN LOCATIONS THAT EXPERIENCE MULTIPLE ROUNDS OF CONVECTION.

TEMPERATURES SHOULD AVERAGE ABOVE NORMAL IN THE WARM SECTOR TO START
THE PERIOD...ALTHOUGH TEMPERATURES SHOULD BE SUPPRESSED ON SUNDAY
AND SUNDAY NIGHT WITH THE FRONT ACROSS THE AREA AND ABUNDANT CLOUD
COVER ANTICIPATED. THEREAFTER...TEMPERATURES SHOULD AVERAGE A BIT
ABOVE NORMAL THROUGH THE REST OF THE PERIOD...WITH HIGHS IN THE MID
70S TO AROUND 80 AND LOWS IN THE UPPER 50S TO AROUND 60.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 800 PM EDT THU MAY 5 2016

EXPECTING CONDITIONS AT THE TAF SITES TO FLUCTUATE BETWEEN VFR
AND MVFR TONIGHT INTO EARLY TOMORROW MORNING...DUE TO LOW CLOUDS
AND SCATTERED RAIN SHOWERS. THE RAIN SHOULD AFFECT PRIMARILY
SJS...SYM...AND JKL THROUGH LATE TONIGHT. THE RAIN IS ASSOCIATED
WITH AN AREA OF LOW PRESSURE ALOFT THAT IS ROTATING ACROSS THE
REGION. LATER TONIGHT...6-12Z TO BE EXACT...THERE SHOULD BE ENOUGH
BREAKS IN THE CLOUDS TO ALLOW FOR SOME FOG TO FORM. THE FOG WILL
BE MOST WIDESPREAD AND DENSE IN THE VALLEYS AND NEAR LARGE BODIES
OF WATER. SME AND LOZ MAY SEE SOME FOG AS WELL BETWEEN 9 AND 12Z
FRIDAY. THE FOG SHOULD BE GONE BY 13Z. CLOUD BASES SHOULD GO TO
VFR AND STAY THERE THROUGH OUT THE DAY ON FRIDAY. ISOLATED TO
SCATTERED RAIN SHOWERS WILL AGAIN BE POSSIBLE IN OUR FAR EAST ON
FRIDAY. SCATTERED TO BROKEN LOW TO MID LEVEL CLOUD COVER WILL ALSO
BE PRESENT. WINDS SHOULD BE OUT OF THE NORTH TO NORTHWEST AT 5 TO
10KTS WITH SOME GUSTS POSSIBLE ON FRIDAY.

&&

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

$$

UPDATE...AR
SHORT TERM...DJ
LONG TERM...JP
AVIATION...AR



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