Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 270236 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1036 PM EDT SAT JUL 26 2014 .UPDATE...
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ISSUED AT 1023 PM EDT SAT JUL 26 2014 UPDATED THE FORECAST TO BETTER REFLECT THE TIMING OF THE MCS MOVING TOWARD THE AREA. THE LAST FEW SCANS...ON THE RADAR...THE MCS APPROACHING FROM THE WEST IS TENDING TO DIVE TO THE SOUTH. THE STRONGEST PORTION OF THE SYSTEM MAY JUST EFFECT THE AREA OF EASTERN KENTUCKY WEST OF I-75. THE HIGHER THETA E VALUES ARE TO THE WEST OF THE AREA...SO THIS BEHAVIOR AND MOVEMENT OF THE SYSTEM MAKES SENSE. THE HRRR IS INDICATING THAT THE ST ROMS WILL WEAKEN AS THEY GET TO EASTERN KENTUCKY. THE BIG SHOW IS STILL TOMORROW AFTERNOON. THE COMBINATION OF ALL OF THE SEVERE PARAMETERS IS SOMETHING RARELY SEEN IN EASTERN KENTUCKY IN JULY. WE WILL HAVE ENHANCED STAFFING AT THE WEATHER OFFICE TOMORROW IN ANTICIPATION OF THE POTENTIAL SEVERE THUNDERSTORMS TOMORROW AFTERNOON.
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&& .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 242 PM EDT SAT JUL 26 2014 DYNAMIC SITUATION UNFOLDING OVER THE NEXT 24 TO 36 HOURS AS A DEEP TROUGH ALOFT DIVES INTO THE OHIO VALLEY. A STRONG COLD FRONT WILL DROP SOUTHEAST INTO THE REGION SUPPLANTING WHAT WILL BECOME A VERY WARM AND VERY MOIST AIRMASS IN PLACE ACROSS OUR REGION. THIS COMBINATION OF A SPRING-TIME SETUP ALOFT COMBINED WITH SUMMER-TIME HEAT AND HUMIDITY WILL CREATE CONDITIONS FAVORABLE FOR A SIGNIFICANT SEVERE WEATHER OUTBREAK ON SUNDAY. MODELS CONTINUE TO INDICATE A THUNDERSTORM COMPLEX WILL ORGANIZE TO OUR WEST THIS AFTERNOON AND EVENING. THIS APPEARS TO BE HAPPENING OVER MISSOURI AT THIS TIME. THESE STORMS SHOULD MARCH EASTWARD INTO THE OVERNIGHT HOURS LIKELY ENDING UP SOMEWHERE OVER SOUTHERN INDIANA AND NORTHERN KENTUCKY BY OR SHORTLY AFTER MIDNIGHT. THIS COMPLEX SHOULD BE WEAKENING AS IT ENTERS OUR FORECAST AREA AFTER MIDNIGHT...BUT CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS AS IT CROSSES THE REGION. THIS THREAT WOULD BE GREATEST FROM JKL AND POINTS TO THE NORTH. THE GREATER SEVERE WEATHER THREAT CONTINUES TO BE THE ANTICIPATED SECOND ROUND OF THUNDERSTORMS EXPECTED TO ERUPT OVER US OR JUST TO OUR NORTH SUNDAY AFTERNOON. PROVIDED EARLY MORNING CONVECTION GETS OUT OF THE WAY IN TIME AND ATMOSPHERE DESTABILIZES AS PROJECTED... THESE STORMS COULD BE QUITE STRONG. SOUNDINGS TOMORROW AFTERNOON ARE IMPRESSIVE. STORM RELATIVE HELICITY VALUES EXCEED 300 M2/S2 COMBINED WITH CAPE PROGGED TO EXCEED 3000 J/KG AND LCLS AROUND 3000 FT MSL. IF THESE CONDITIONS VERIFY...A RARE JULY TORNADO OUTBREAK COULD OCCUR. STILL...LOTS OF UNCERTAINTY WITH HOW TONIGHTS ACTIVITY WILL PAN OUT AND HOW THIS WILL AFFECT OUR CONDITIONS ON SUNDAY BUT WILL CONTINUE TO PLAY UP THE SEVERE WEATHER POTENTIAL IN OUR SUITE OF PRODUCTS. IN ADDITION TO THE SEVERE WEATHER CONCERNS...ISOLATED FLASH FLOODING IS A CONCERN PRIMARILY ON SUNDAY. MOISTURE POOLING IN ADVANCE OF THE FRONT WILL PUSH SURFACE DEWPOINTS INTO THE LOW TO MID 70S AND PWATS WILL JUMP TO 1.75 INCHES AND ABOVE. STORM MOTIONS LOOK FAST ENOUGH TO PRECLUDE A WIDESPREAD FLASH FLOODING THREAT...BUT AGAIN THAT WILL DEPEND LARGELY ON HOW PRIMED WE GET BY TONIGHTS CONVECTION. NO FLASH FLOOD WATCH WILL BE ISSUED AT THIS TIME...BUT THAT MAY NEED TO BE REVISITED SHOULD THE INITIAL ROUND OF CONVECTION SATURATE THE GROUND TONIGHT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 242 PM EDT SAT JUL 26 2014 AN ANOMALOUS LARGE AND DEEP UPPER TROUGH WILL PERSIST OVER THE EASTERN CONUS THROUGH THE PERIOD. THE SURFACE COLD FRONT MARKING THE LEADING EDGE OF THE UNSEASONABLY COOL AIR MASS UNDER THE TROUGH WILL BE WELL TO OUR SOUTHEAST ALREADY AS THE PERIOD STARTS...BUT RESIDUAL LOW LEVEL MOISTURE WILL STILL BE MIXING VERTICALLY INTO THE NEW AIR MASS AS COOLING ALOFT OCCURS. THIS MAY RESULT IN A FEW SHOWERS OR THUNDERSTORMS MONDAY AFTERNOON OR EVENING...ESPECIALLY IN OUR NE COUNTIES WHERE COOLER MID LEVEL TEMPS ARE EXPECTED. ON TUESDAY...DRIER SURFACE AIR AND A MID LEVEL CAP SHOULD KEEP CONVECTIVE CURRENTS BELOW ABOUT 10K FEET. SOME LIQUID COULD STILL TRY TO FALL OUT OF THE CLOUDS...BUT WITH LIMITED CLOUD DEPTH AND DRIER AIR...WILL ONLY MENTION SPRINKLES IN THE FORECAST. A COOL AND DRY AIR MASS FIRMLY IN PLACE...COUPLED WITH A CESSATION OF COOLING ALOFT...WILL ALLOW FOR MAINLY CLEAR SKIES FROM TUESDAY NIGHT THROUGH THURSDAY NIGHT. NEAR RECORD LOW TEMPS WILL BE A POSSIBILITY. AS THE HIGHLY AMPLIFIED UPPER TROUGH WEAKENS AT THE END OF THE WEEK...MODELS AGREE ON ITS AXIS RETROGRADING TO THE WEST AS A LOW CLOSES OFF. WITH THE LOW/TROUGH AXIS SLIPPING TO OUR WEST...WE WILL RETURN TO ITS EAST SIDE WHICH IS SYNOPTICALLY MORE FAVORABLE FOR PRECIP. FLOW FROM THE GULF OF MEXICO WILL STILL BE CUT OFF AND LOW LEVEL MOISTURE WILL BE SLOW TO INCREASE...SO WILL ONLY USE LOW POPS. && .AVIATION...
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(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 1023 PM EDT SAT JUL 26 2014 VFR CONDITIONS ARE ANTICIPATED THROUGH THE FIRST HALF OF THE TAF PERIOD WITH LIGHT WINDS. UPDATED THE FORECAST TO BETTER REFLECT THE TIMING OF THE MCS MOVING TOWARD THE AREA. THE LAST FEW SCANS...ON THE RADAR...THE MCS APPROACHING FROM THE WEST IS TENDING TO DIVE TO THE SOUTH. THE STRONGEST PORTION OF THE SYSTEM MAY JUST EFFECT THE AREA OF EASTERN KENTUCKY WEST OF I-75. THE HIGHER THETA E VALUES ARE TO THE WEST OF THE AREA...SO THIS BEHAVIOR AND MOVEMENT OF THE SYSTEM MAKES SENSE. THE HRRR IS INDICATING THAT THE ST ROMS WILL WEAKEN AS THEY GET TO EASTERN KENTUCKY. THE BIG SHOW IS STILL TOMORROW AFTERNOON. THE COMBINATION OF ALL OF THE SEVERE PARAMETERS IS SOMETHING RARELY SEEN IN EASTERN KENTUCKY IN JULY. WE WILL HAVE ENHANCED STAFFING AT THE WEATHER OFFICE TOMORROW IN ANTICIPATION OF THE POTENTIAL SEVERE THUNDERSTORMS TOMORROW AFTERNOON. EXPECTING MOSTLY MVFR CIGS AND VSBY FOR THE AREA...HOWEVER SOME OF STRONGER STORMS COULD BE CAPABLE OF DROPPING THE VSBY TO AROUND A MILE AND PRODUCE WIND GUSTS OF 40 TO 50 KTS. THIS IS MORE LIKELY TO OCCUR WITH STORMS DURING THE AFTERNOON. PUT TWO TEMPO GROUPS IN THE TAFS TO REFLECT THE MOST LIKELY TIMES THAT THE STORMS WILL BE IN THE AREA...HOWEVER THUNDERSTORMS ARE POSSIBLE ANYTIME AFTER ABOUT 5Z.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJ SHORT TERM...ABE LONG TERM...HAL AVIATION...JJ

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