Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 271802 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 202 PM EDT MON JUL 27 2015 .UPDATE... ISSUED AT 200 PM EDT MON JUL 27 2015 SHOWERS AND THUNDERSTORMS HAVE REFORMED ACROSS MUCH OF THE AREA BUT THANKFULLY SOUTH OF LOCATIONS THAT RECEIVED LOCALLY HEAVY DOWNPOURS EARLIER TODAY. DUE TO THE INCREASED AREAL COVERAGE HAVE INCREASED POPS TO LIKELY ACROSS THE MUCH OF THE AREA AS WELL. ALSO WILL HAVE ACTIVITY LASTING A BIT LONGER INTO THE EVENING AND OVERNIGHT HOURS AS WITH THE AIR MASS CURRENTLY IN PLACE...IT WONT TAKE MUCH TO POP ANOTHER SHOWER OR STORM LATER. THIS UPDATE WILL REQUIRE A NEW ZFP AND SOME FRESHENED GRIDS. UPDATE ISSUED AT 943 AM EDT MON JUL 27 2015 CURRENT CONDITIONS ACROSS THE AREA AS OF 1330Z FEATURE A CLUSTER OF SHOWERS AND THUNDERSTORMS MOVING THROUGH THE BLUEGRASS PORTION OF NORTHERN KY AND INTO NORTHEAST KY. CURRENT DUAL POL ESTIMATES HAVE BEEN AROUND AN INCH AN HOUR BUT THESE CELLS SEEM TO BE MOVING ALONG AT A DECENT CLIP AND THE HEAVY RAIN IS NOT EXPECTED TO BE AN ISSUE. THE MOIST AND UNSTABLE ATMOSPHERE THIS MORNING WILL ALLOW THE SHOWERS AND STORMS TO CONTINUE INTO THE LATE MORNING HOURS AS THEY TRACK TO THE EAST. SO...MAIN UPDATES THIS MORNING WAS TO INCREASE POPS IN THE NORTH AS THIS CLUSTER MOVES THROUGH AND DROP THE MORNING AND FOG WORDING. ALSO EXPECTED WILL BE RENEWED DEVELOPMENT THIS AFTERNOON...ESPECIALLY WITH ADDITIONAL ACTIVITY UPSTREAM MOVING IN THIS AFTERNOON. UPDATE ISSUED AT 634 AM EDT MON JUL 27 2015 ISOLATED SHOWERS HAVE BEGUN POPPING UP OVER THE LAST COUPLE OF HOURS ACROSS PORTIONS OF CENTRAL AND EASTERN KY. THIS WAS A FEW HOURS SOONER THAN FORECASTED...SO MAIN CHANGE DURING THIS UPDATE WAS TO MAKE SURE THE POPS AND WEATHER BETTER REFLECTED THE ONGOING CONDITIONS. KEPT ISOLATED POPS IN THROUGH THE MORNING...THOUGH IF THE LARGER AREA OF SHOWERS CURRENTLY MOVING OVER CENTRAL KY IS ABLE TO HOLD TOGETHER AS IT REACHES OUR WESTERN CWA...POPS MAY NEED TO BE UPGRADED ONCE MORE. AS THE SUN RISES...BETTER INSTABILITY WILL LIKELY RESULT IN MORE LIGHTNING STRIKES AND RUMBLES OF THUNDER WITH ANY OF THESE CELLS. PARAMETERS ARE STILL NOT LOOKING VERY FAVORABLE FOR SEVERE DEVELOPMENT TODAY...THOUGH THE SLOW WEST TO EAST NATURE OF THE STORMS ALONG THE NEARLY STATIONARY BOUNDARY MAY LEAD TO SOME TRAINING OR LOCATIONS EXPERIENCING HEAVY RAINS FOR AN EXTENDED PERIOD OF TIME. THIS WILL NEED TO BE MONITORED AS WE GO THROUGHOUT THE DAY. FINALLY...LOADED IN THE LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS...TO MAKE SURE THAT THESE NEAR TERM GRIDS WERE REFLECTING THE CURRENT CONDITIONS. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 316 AM EDT MON JUL 27 2015 A WEAK SURFACE BOUNDARY HAS SHIFTED SOUTH ACROSS THE OHIO RIVER AND CURRENTLY SITS JUST NORTH OF OUR CWA. SHOWERS AND THUNDERSTORMS ARE STILL SHOWING UP ALONG AND NEAR THIS BOUNDARY EARLY THIS MORNING...BUT ARE CONTINUING TO SHOW A DIMINISHING TREND. AS SUCH...NOT EXPECTING THIS CONVECTION TO MAKE IT INTO THE CWA BEFORE 12Z. WPC SHOWS THE FRONT REMAINING NEARLY STATIONARY THROUGH THE MORNING HOURS...BEFORE FINALLY SHIFTING SLOWLY SOUTHWARD THROUGH CENTRAL KY LATE IN THE AFTERNOON. WITH THE INTRODUCTION OF DAYTIME HEATING AFTER 12Z THIS MORNING...EXPECT THIS BOUNDARY...THOUGH WEAK...TO PROVIDE ENOUGH LIFT AND INSTABILITY TO SPARK A NEW SET OF SHOWERS AND THUNDERSTORMS. MODELS CONTINUE TO PEG THE FAR SE AS THE EPICENTER FOR MOST OF THESE SHOWERS AND THUNDERSTORMS...PERHAPS DUE TO THE EASTERLY AND SLIGHT UPSLOPE FLOW. HOWEVER...GIVEN THE WEAK NATURE OF THE BOUNDARY...IN ADDITION TO THE VERY LIGHT WINDS...DO NOT EXPECT THUNDERSTORMS TO BE STRONG IN NATURE OR VERY SUSTAINABLE/LONG LIVED ACROSS ANY PART OF THE CWA. THE BOUNDARY WILL LIKELY REMAIN PARKED ACROSS KY TONIGHT AND POSSIBLY EVEN INTO THE DAY TUESDAY BEFORE IT FINALLY FADES OUT. THIS COULD KEEP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE CWA THROUGH THIS ENTIRE TIME PERIOD...THOUGH LOSS OF DAYTIME HEATING WILL LIKELY CUT DOWN ON THUNDER CHANCES OVERNIGHT TONIGHT...ALONG WITH SOME OF THE CU DEVELOPMENT. DIURNALLY DRIVEN CU WILL BEEF BACK UP THE CLOUD COVER SOMEWHAT DURING THE DAY TUESDAY AS BETTER CONVECTION ENSUES. HOWEVER...AS THE BOUNDARY CONTINUES TO FADE...SO TO WILL THE BEST LIFT...MOISTURE...CLOUDS...AND PRECIP CHANCES DURING THE AFTERNOON TUESDAY. EXPECT MOST OF THE PRECIP TO HAVE DIMINISHED BY TUESDAY EVENING. AS FAR AS TEMPERATURES...THIS FRONTAL BOUNDARY...AS ADVERTISED... WILL BE WEAK ENOUGH TO CAUSE LITTLE EFFECT ON THE WARM AIR MASS. LIGHT WINDS AT THE SURFACE WILL GIVE WAY TO A STRONGER NW FLOW ALOFT. HOWEVER...WITH A BUILDING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS...WARM AIR ALOFT WILL BE PULLED FROM THE SOUTH CENTRAL CONUS/GULF COAST...NORTHWARD INTO THE CENTRAL PLAINS...AND THEN EASTWARD TOWARDS THE OHIO VALLEY. IN ESSENCE...NW FLOW WILL ACTUALLY RESULT IN THE CONTINUED PULL OF WARMER AIR INTO THE REGION. AS SUCH...HIGH TEMPS BOTH TODAY AND TOMORROW WILL CONTINUE TO HOVER IN THE UPPER 80S TO AROUND 90. TEMPERATURES OVERNIGHT WILL MIMIC THOSE OF EARLY THIS MORNING...STAYING NEAR THE 70 DEGREE MARK WITH HIGH HUMIDITIES. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 502 AM EDT MON JUL 27 2015 A STRONG UPPER LEVEL HIGH WILL BE OVER THE SOUTHERN PLAINS AT THE START OF THE PERIOD...WITH RIDGING EXTENDING NORTHEAST OVER THE GREAT LAKES. THIS WILL RESULT IN LIGHT FLOW ALOFT WITH VERY LITTLE IN THE WAY OF FEATURES. ENOUGH HEATING AND SURFACE MOISTURE MAY BE PRESENT TO FUEL SOME THUNDERSTORMS TUESDAY EVENING AND AGAIN WEDNESDAY AFTERNOON...MAINLY OVER THE HIGHER TERRAIN. HOWEVER...MOSTLY DRY WEATHER IS EXPECTED. AN UPPER LOW RIDING ACROSS THE TOP OF THE RIDGE OVER CANADA WILL FLATTEN THE RIDGE AND SEND IT RETROGRADING TO THE WEST LATE IN THE WEEK...WITH A BROAD TROUGH RESULTING OVER THE EASTERN CONUS. THIS WILL SEND A COLD FRONT SOUTHEAST THROUGH THE JKL FORECAST AREA WEDNESDAY NIGHT AND THURSDAY. MODELS GENERATE SOME PRECIP WITH THE FRONT...BUT ARE LOOKING LESS IMPRESSIVE IN RECENT RUNS. HAVE USED 20-30 PERCENT POPS. SURFACE HIGH PRESSURE BUILDING IN BEHIND THE COLD FRONT WILL BRING A DRIER AIR MASS FOR THURSDAY NIGHT INTO THE WEEKEND...RESULTING IN MOSTLY CLEAR SKIES WITH COOL NIGHTS AND WARM DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 200 PM EDT MON JUL 27 2015 A WEAK SURFACE BOUNDARY OVER THE AREA ALONG WITH A VERY MOIST AND UNSTABLE AIRMASS WILL KEEP THE THREAT OF SHOWERS AND THUNDERSTORMS OVER THE AREA THROUGH MUCH OF THE EVENING AND INTO TONIGHT. THEREFORE...HAVE LEFT SOME VCTS MENTION IN THE TAFS. FOG TONIGHT WILL BE QUITE THE CHALLENGE AS SOME LEFTOVER CLOUD COVER FROM CONVECTION MAY HINDER FOG DEVELOPMENT BUT THE AMOUNT OF MOISTURE IN THIS AIRMASS WILL MAKE FOR RATHER EASY FOG DEVELOPMENT. AT THE VERY LEAST...HAVE PUT SOME FIELD MINS AND BELOW AT LOZ AND SME WITH BELOW MVFR CONDITIONS AT THE OTHER SITES. HEADING INTO THE DAY ON TUESDAY...AFTERNOON DEVELOPMENT SEEMS LIKELY AGAIN AND HAVE PUT IN SOME VCTS IN THE TAFS. WINDS SHOULD BE LIGHT THROUGH THE REST OF THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...JMW LONG TERM...HAL AVIATION...SHALLENBERGER

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