Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 260619 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 219 AM EDT TUE AUG 26 2014 .SHORT TERM...
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(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.
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&& .AVIATION...
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(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 219 AM EDT TUE AUG 26 2014 VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE TAF SITES FOR THE NEXT 36 HOURS. THERE SHOULD BE JUST ENOUGH MOISTURE AVAILABLE FOR A FEW CLOUDS TO OCCASIONALLY FORM AROUND 5 AND 12K THROUGH THE END OF THE DAY ON TUESDAY. HOWEVER...THE AIR MASS THAT IS IN PLACE IS DRY ENOUGH THAT ANY FOG FORMATION THAT OCCURS TONIGHT SHOULD BE CONFINED TO OUR RIVER VALLEYS...AND THEREFORE IS NOT EXPECTED TO AFFECT ANY OF THE TAF SITES.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JJ LONG TERM...JMW AVIATION...JJ

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