Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 261136
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
736 AM EDT TUE AUG 26 2014

.UPDATE...
ISSUED AT 735 AM EDT TUE AUG 26 2014

UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE REST OF THE FORECAST IS ON TRACK.

UPDATE ISSUED AT 605 AM EDT TUE AUG 26 2014

UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE REST OF THE FORECAST IS ON TRACK.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 219 AM EDT TUE AUG 26 2014

THE MODELS ARE IN GOOD AGREEMENT AS HIGH PRESSURE DOMINATES BOTH AT
THE SURFACE AND ALOFT. THE UPPER RIDGE AXIS EXTENDS INTO THE TEXAS
PANHANDLE. THERE IS AN UPPER LOW OVER NORTHERN NEVADA AND THE THERE
IS FAIRLY ZONAL FLOW ON THE NORTHERN STREAM WHICH EXTENDS ALONG THE
NORTHERN TIER AND THEN ACROSS THE GREAT LAKES. THE COLD FRONT THIS
MORNING WILL EXTEND FROM A SURFACE LOW OVER MICHIGAN TO ANOTHER LOW
OVER SOUTHWESTERN KANSAS. WITH TIME...THE UPPER LOW MOVES SLOWLY TO
THE EAST AND THE UPPER RIDGE AXIS WILL SLOWLY SHIFT TO THE SOUTH
ALLOWING THE FRONT TO SINK A LITTLE TO THE SOUTH BY WEDNESDAY
MORNING. THIS WILL ALLOW SOME SHOWERS AND THUNDERSTORMS TO MOVE INTO
THE BLUEGRASS AND FAR WESTERN PORTIONS OF EASTERN KENTUCKY. BY
WEDNESDAY EVENING THE FRONT IS FORECAST TO BE IN THE OHIO VALLEY.
THERE IS SOME UNCERTAINTY ON THE POSITION OF THE FRONT AND AS SUCH
UNCERTAINTY ON HOW FAR SOUTH THE RAINSHOWERS AND THUNDERSTORMS WILL
EXTEND INTO EASTERN KENTUCKY. USED THE MODEL BLEND AS A MEDIATING
POSITION FOR THE SOUTHERN EXTENT OF THE RAIN. TEMPERATURES WILL REMAIN
ABOVE NORMAL THROUGH WEDNESDAY. THE ECMWF HAS BEEN FORECASTING LOWER
HIGHS FOR WEDNESDAY...HOWEVER ADJUSTED THE MODEL BLEND UP A LITTLE
FOR WEDNESDAY AS THE ECMWF SEEMED TO BE AN OUTLIER.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 AM EDT TUE AUG 26 2014

EXTENDED FORECAST WILL CENTER AROUND EXITING UPPER LEVEL
RIDGING...WHICH HAS BEEN THE MAIN WEATHER DRIVE FOR THE LAST SEVERAL
DAYS...AND A STRENGTHENING TROUGH OVER THE PLAINS WHICH WILL SLOWLY
PUSH INTO THE OHIO RIVER VALLEY REGION BY THE END OF THE FORECAST
PERIOD. WITH KENTUCKY FINDING ITSELF IN A TRANSITION PERIOD DURING
MUCH OF THE FORECAST...MODELS ARE STILL HAVING A HARD TIME COMING
INTO GOOD AGREEMENT ON ANY PARTICULAR SOLUTION/TIMING ESPECIALLY IN
THE DAYS 4 THROUGH 7 TIME FRAME. WHILE ALL SOLUTIONS ARE POINTING AT
THE SAME OVERALL PATTERN...THE EXACT TIMING AND LOCATION OF
IMPACTING PRECIP AND TROUGH/FRONTAL PASSAGES IS STILL SOMEWHAT UP IN
THE AIR. WILL START WITH ALLBLEND AS BEST FIRST GUESS FOR THIS TIME
PERIOD.

AS FOR IMPACTFUL WEATHER...A SURFACE FRONT WILL BE PUSHING SE INTO
EASTERN KY BY 0Z THURSDAY. HOWEVER...GIVEN THE RIDGING PATTERN STILL
IN PLACE ALOFT...AND STRONG SURFACE HIGH PRESSURE ON EITHER SIDE OF
THE SYSTEM...EXPECT THIS BOUNDARY TO LOSE CONSIDERABLE STRENGTH AS
IT SLOWLY MOVES SOUTH OF THE REGION BY LATE IN THE DAY THURSDAY. AS
SUCH...WILL KEEP WITH SCATTERED CONVECTIVE CHANCES...BUT OVERALL
COVERAGE WILL BE LACKING. THE ECMWF IS THE HARDEST HITTING WITH
POTENTIAL POPS...BUT THIS RUN IS AN OUTLIER TO THE GFS40...GEM...AND
NAM...SO WILL PUT LESS FAITH IN THIS SOLUTION. EVENTUALLY WITH LOSS
OF DAYTIME HEATING THURSDAY EVENING...EXPECT MOST PRECIP CHANCES TO
DIMINISH ALL TOGETHER ACROSS THE REGION...AS ENERGY FOCUSES ALONG
ANOTHER BOUNDARY DEVELOPING TO OUR NW. THIS BOUNDARY /A SURFACE COLD
FRONT/ WILL BE ASSOCIATED WITH STRONG UPPER LEVEL TROUGHING OVER THE
GREAT PLAINS...WITH THE FRONT STRETCHING NORTHWARD TO A SURFACE LOW
TRAVERSING SOUTHERN CANADA.

AS THE UPPER LEVEL PATTERN SLOWLY SHIFTS EASTWARD TOWARDS THE
REGION...SO WITH THE SURFACE LOW AND BOUNDARY...ALL WORKING TOGETHER
TO MAKE THIS A FAIRLY ORGANIZED AND POTENT SYSTEM. ENERGY AHEAD OF
THIS SYSTEM...AND SOME LINGERING MOISTURE ACROSS THE AREA...COULD
LEAD TO A FEW AFTERNOON SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
EASTERN KY. OTHERWISE...DON/T EXPECT THE FIRST ROUND OF PRECIP FROM
THIS SYSTEM TO BEGIN AFFECTING OUR PORTION OF THE STATE UNTIL LATE
INTO THE DAY SATURDAY. THIS IS STILL ON TRACK WITH PREVIOUS FORECAST
THINKING AS WELL. AS WAS MENTIONED PREVIOUSLY...EXACT
TIMING/COVERAGE/AND STRENGTH OF THIS SYSTEM IS STILL SOMEWHAT
LACKING IN COLLECTIVE AGREEMENT. BUT THE TROUGH SHOULD LOSE STRENGTH
AND DAMPEN AS IT MOVES INTO THE REGION...WITH THE SURFACE LOW
EXPECTED TO RACE EASTWARD AHEAD OF THE ACTUAL FRONT. THIS WILL KEEP
THE FRONT FROM ACTUALLY PUSHING ACROSS EASTERN KY ACCORDING TO THE
LATEST GFS FRONTAL ANALYSIS. IT WILL...HOWEVER...BRING STRONG
SOUTHERLY FLOW OFF THE GULF OF MEXICO WITH A WARM MOIST CONVEYOR
BELT FLOWING RIGHT INTO THE OHIO RIVER VALLEY AND MUCH OF THE
SOUTHERN COASTAL STATES. GIVEN THE WEST TO EAST ORIENTATION OF THE
FRONT FOR SATURDAY THROUGH MONDAY...WIDESPREAD CONVECTIVE CHANCES
WILL BE POSSIBLE ALL THREE DAYS. GIVEN THE LATEST FORECAST
SOUNDINGS...IF ALL HOLDS TRUE...COULD SEE SOME GOOD RAINFALL FROM
THIS SYSTEM /NO WONDER CONSIDERING THE AMOUNT OF GULF MOISTURE
AVAILABLE/...BUT THE OVERALL CAPE AND LAPSE RATE VALUES ARE NOT
GENERALLY IMPRESSIVE. IN SUCH CASE...EXPECT MAINLY A RAIN SHOWER
EVENT...WITH SCATTERED BRIEF THUNDERSTORMS IN THE HEAVIEST
RAINERS...RATHER THAN A WIDESPREAD STORM OUTBREAK. THIS IS FURTHER
SUPPORTED BY THE TRACK OF THE SYSTEM...AS MUCH OF THE BETTER FORCING
SEEMS TO BE CONCENTRATED WELL TO OUR NORTH CLOSER TO THE SURFACE LOW
AND APEX BETWEEN THE WARM AND COLD FRONT.

AS FOR TEMPERATURES...EXPECT MID AND UPPER 80S TO CONTINUE INTO
SATURDAY WITH SOUTHERLY FLOW IN PLACE. THEN BY
SATURDAY...TEMPERATURES SHOULD DROP A COUPLE DEGREES AND REMAIN IN
THE LOW TO MID 80S FOR THE NEXT COUPLE DAYS AS CLOUD COVER REDUCES
SOLAR HEATING. ANY ONGOING RAIN COULD FURTHER INHIBIT
MAXIMUM TEMPERATURE POTENTIAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 735 AM EDT TUE AUG 26 2014

THE ARE SOME PATCHES OF BROKEN MVFR STRATOCU AROUND...HOWERVER THEY
SHOULD BE LIFTING TO VFR BY 14Z. EXPECT VFR TO CONTINUE UNTIL AFTER
6-9Z WHEN MVFR VALLEY MIST WILL BE FORMING AT SOME OF THE TAF SITES
AND WILL HANG AROUND UNTIL THE END OF THE PERIOD.

&&

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

$$

UPDATE...JJ
SHORT TERM...JJ
LONG TERM...JMW
AVIATION...JJ






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