Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 040030 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 830 PM EDT FRI JUL 3 2015 .UPDATE... ISSUED AT 810 PM EDT FRI JUL 3 2015 23Z SFC ANALYSIS SHOWS LOW PRESSURE RIDING THROUGH EAST KENTUCKY ALONG A STALLED FRONTAL BOUNDARY. THIS BOUNDARY HAS BROUGHT SHOWERS...THUNDERSTORMS...AND FLOODING TO THE AREA FOR THE PAST COUPLE OF DAYS. THAT CONTINUES TONIGHT WITH LOW CENTROID CONVECTION TRAINING AS IT SLOWLY MARCHES WEST TO EAST INTO THE AREA. MUCH OF THE HEAVY RAINS CONTINUE TO FALL IN AREAS WITH VERY LOW FFG AND PLACES THAT HAVE ALREADY RECEIVED EXCESSIVE RAINS LIKE PULASKI AND LAUREL COUNTIES. AS A RESULT...FLASH FLOOD AND AREAL WARNINGS ARE OUT FOR MUCH OF THE CUMBERLAND VALLEY ALONG AND WEST OF I-75. THE RAINS CONTINUE TO THE EAST BUT ARE WEAKENING OR RAINING THEMSELVES OUT AS THEY MOVE INTO AREAS THAT HAVE NOT BEEN HIT QUITE SO HARD RECENTLY. EVEN SO...IT WILL NOT TAKE MUCH TRAINING FOR FLOOD ISSUES TO DEVELOP FURTHER EAST IN THE SOUTHERN HALF OF THE CWA. HAVE UPDATED THE FORECAST TO REFINE THE POPS FOR THE REST OF THE EVENING AS THE BANDS OF CONVECTION SLOWLY SETTLES SOUTH. ALSO UPPED THE QPF ACROSS THE SOUTH AND ADDED SOME FOG TO THE GRIDS THROUGH THE NIGHT...BECOMING LOCALLY DENSE LATE. FINALLY...TWEAKED THE NEAR TERM TEMPS AND DEWPOINTS BASED ON THE LATEST OBS AND TRENDS. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH A FRESHENED ZFP. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 317 PM EDT FRI JUL 3 2015 BASED ON WIND READINGS ACROSS THE REGION...FRONTAL BOUNDARY LOOKS TO RESIDE FROM BETWEEN MOREHEAD AND FLEMINGSBURG...BACK TO THE EAST TO FRANKFORT AND LOUISVILLE. BREAKS IN THE CLOUDS IN WESTERN AND CENTRAL KENTUCKY HAS ALLOWED FOR 2500J/KG OF SBCAPE TO DEVELOP. IN ADDITION...WE ACTUALLY HAVE SOME 30-35 KNOTS OF EFFECTIVE BULK SHEAR RESIDING ACROSS EASTERN KENTUCKY. SHOWERS AND STORMS CONTINUE TO LIGHT UP ALONG AND SOUTH OF THE FRONTAL BOUNDARY WITH THE HIGHEST CONCENTRATION CLOSER TO THE BOUNDARY. UNFORTUNATELY...ACTIVITY IS ONCE AGAIN ALIGNED EAST TO WEST AND WILL TRACK ACROSS THE RED RIVER BASIN AGAIN INTO THIS EVENING. THIS WILL CONTINUE TO LEAD TO THE THREAT OF FLASH FLOODING. GIVEN THE FAVORABLE CONDITIONS OF INSTABILITY AND SHEAR...THIS ACTIVITY SHOULD CONTINUE TO PUSH EAST THROUGH THE EVENING HOURS. WHILE ACTIVITY MAY DECREASE AS WE HEAD OVERNIGHT...FRONT WILL STILL RESIDE ACROSS THE AREA...LEADING TO A CONTINUATION IN THE FLASH FLOOD THREAT THROUGH TONIGHT. BY TOMORROW...FRONT FINALLY SLIPS SOUTH TAKING THE BULK OF THE ACTIVITY TO OUR SOUTH...HOWEVER...THE BOUNDARY MAY STILL TRIGGER A FEW SHOWERS AND STORMS DURING THE AFTERNOON. THEY SHOULD BE MORE HIT OR MISS ON SATURDAY AND MAINLY CONFINED TO THE TIMES OF PEAK INSTABILITY IN THE AFTERNOON/EVENING. SATURDAY NIGHT WILL FEATURE QUIETER WEATHER AS DIURNALLY DRIVEN SHOWERS/STORMS DIE OFF AROUND SUNSET. STILL HAVE TO WATCH FOR SOME LOCALLY DENSE FOG IN PLACES. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH SATURDAY NIGHT AS WE REMAIN UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 515 PM EDT FRI JUL 3 2015 THE MODELS ARE IN FAIRLY GOOD GENERAL AGREEMENT CONCERNING THE UPPER PATTERN INTO ABOUT MID WEEK. THEY ALL AGREE THAT A WEAK TROUGH WILL START TO PIVOT SLOWLY NORTHEAST AND OUT OF THE TENNESSEE AND OHIO VALLEYS SUNDAY INTO MONDAY. HOWEVER...THE BULK OF ITS CONSIDERABLE ENERGY WILL SWIRL OVER EASTERN KENTUCKY DURING THIS PROCESS ONLY CLEARING OUT TOWARDS TUESDAY MORNING. THIS MOVEMENT IN THE PATTERN WILL BE THANKS TO A ROBUST TROUGH CROSSING THROUGH CENTRAL CANADA AND SWEEPING OVER THE GREAT LAKES MONDAY NIGHT INTO TUESDAY. THE GFS AND ECMWF ARE SIMILAR WITH THE TIMING AND PLACEMENT OF THIS...THOUGH THE ECMWF IS STRONGER AND ACTUALLY CLOSED OFF WITH ITS LOW. MEANWHILE...THE CANADIAN IS WEAKER STILL THAN THE GFS ALONG WITH BEING SLOWER. AS THIS FEATURE PASSES... HEIGHTS WILL RISE LOCALLY...THOUGH SOME WEAK ENERGY WILL REMAIN OVER KENTUCKY THROUGH THE DAY WEDNESDAY. FOLLOWING THIS...THE GFS CONTINUES WITH HIGHER HEIGHTS OVER THE REGION...WHILE THE ECMWF TAKES ANOTHER TROUGH INTO THE GREAT LAKES AND NORTHEAST OHIO VALLEY WITH A WAVE OF ENERGY PASSING OVER KENTUCKY LATER THURSDAY. THE MODELS THEN ARE IN BETTER AGREEMENT IN SHOWING MORE RIDGING TO END THE WEEK. A GENERAL MODEL BLEND LOOKS REASONABLE AT LEAST THROUGH TUESDAY BEFORE A SLIGHT LEAN TOWARD THE LESS PROGRESSIVE ECMWF SEEMS IN ORDER GIVEN RECENT TRENDS. SENSIBLE WEATHER WILL LIKELY SEE AN END TO ANY BREAK FROM THE WET WEATHER WE MAY ENJOY FROM SATURDAY INTO SUNDAY MORNING AS A LOW PRESSURE WAVE PASSING JUST SOUTH OF THE AREA WILL SHIFT THE FRONT BACK NORTH INTO OUR AREA DURING THE DAY SUNDAY WITH ATTENDANT SHOWERS AND THUNDERSTORMS. THE CONVECTION SHOULD BE MORE DIURNALLY DRIVEN INTO THE START OF THE WEEK WITH ACTIVITY BECOMING MORE SCATTERED AFTER SUNSET LASTING THROUGH MID MORNING. THE GREAT LAKES TROUGH AT MID LEVELS WILL SEND A SLOW MOVING COLD FRONT INTO THE AREA ON TUESDAY WITH RENEWED HIGHER CHANCES OF SHOWERS AND THUNDERSTORMS. THE POPS WILL REMAIN ELEVATED THROUGH THURSDAY AS THE FRONT LAYS OUT AND LINGERS OVER THE STATE WHILE ANOTHER SFC WAVE RUNS EAST ALONG IT...MOVING FROM THE SOUTHERN PLAINS TO THE CENTRAL APPALACHIANS TUESDAY NIGHT THROUGH THURSDAY AFTERNOON. AGAIN HEAVY RAINS WILL BE A CONCERN WITH THIS BOUNDARY AS A WIDE OPEN GULF OF MEXICO WILL HELP TO SUPPORT HIGH PWATS ACROSS THE STATE. SHOULD THE ECMWF TURN OUT MORE CORRECT AND THE FRONT SAGS SOUTH WE MAY ACTUALLY SEE SOME DRYING FOR THE END OF THE WEEK. HOWEVER...THE GFS LINGERS THE FRONT OVERHEAD SO WILL MAINTAIN A SMALL CHANCE FOR CONVECTION TO CLOSE OUT THE UPCOMING WORK WEEK. GIVEN THE CONVECTION AND CLOUD COVER EXPECTED THROUGHOUT THE FORECAST...TEMPERATURES WILL BE JUST ON THE COOL SIDE OF NORMAL FOR HIGHS AND ABOVE NORMAL AT NIGHT FOR LOWS...WITH HUMID DAYS AND MUGGY NIGHTS. THE CR GRID BLEND CAME IN REASONABLY WELL WITH THE BULK OF ANY ADJUSTMENTS MADE TO THE POPS AND SKY TO ACCOUNT FOR THE DIURNAL CYCLE EARLY ON FOLLOWED BY A LEAN TOWARD THE ECMWF LATE IN THE PERIOD. AS FOR TEMPERATURES...DID TWEAK THE LOWS A BIT EACH NIGHT TO REFLECT ONLY MINOR TERRAIN EFFECTS GIVEN THE HIGH MOISTURE ENVIRONMENT IN PLACE FOR THE EXTENDED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 830 PM EDT FRI JUL 3 2015 WIDESPREAD SHOWERS AND THUNDERSTORMS WILL IMPACT MOST SITED THROUGH THE REST OF THE EVENING WITH VARIABLE CIGS AND VIS THE RESULT. AMID THIS A DISTINCT TREND TOWARD LOWER AVIATION CATEGORIES WILL BE NOTED. AFTER MIDNIGHT...EXPECT LESS IN THE WAY OF STORMS AROUND BUT ALSO LOWER...IFR/LIFR...CIGS AND VIS DUE TO THE SATURATED AIR MASS IN PLACE ALONG WITH SCATTERED SHOWERS. THESE CONDITIONS WILL LIKELY IMPROVE LATER SATURDAY MORNING...BUT THAT WILL MOST PROBABLY JUST HELP FUEL ANOTHER ROUND OF SHOWERS AND STORMS FOR THE AFTERNOON...MAINLY IN THE SOUTHERN PARTS OF THE FORECAST AREA. WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE...OUTSIDE OF ANY STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...KAS LONG TERM...GREIF AVIATION...GREIF

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