860  
FXUS63 KJKL 172038  
AFDJKL  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSON KY  
438 PM EDT SUN JUN 17 2018  
   
SHORT TERM
 
(THIS EVENING THROUGH MONDAY NIGHT)  
ISSUED AT 359 PM EDT SUN JUN 17 2018  
 
HIGH PRESSURE IS STILL IN CONTROL OF MUCH OF EASTERN KENTUCKY AND  
SURROUNDING AREAS. MEANWHILE A WEAK UPPER LEVEL LOW IS IMPACTING  
PORTIONS OF THE DEEP SOUTH, INTERACTING WITH THE WARM AND HUMID  
AIRMASS IN PLACE TO PRODUCE SHOWERS AND THUNDERSTORMS. THESE  
SHOWERS AND THUNDERSTORMS EXTEND NORTHWARD INTO TN DUE TO THE  
WARM/MOIST AIRMASS IN PLACE, WITH THE POTENTIAL FOR ISOLATED  
CONVECTION AS FAR NORTH AS SOUTHERN KY. IN FACT OUR FIRST SMALL  
SHOWERS JUST POPPED UP ACROSS MCCREARY AND HARLAN COUNTIES. HAVE  
ISOLATED SHOWERS/THUNDERSTORMS REFLECTED IN THE POPS THROUGH THE  
LATE AFTERNOON.  
 
FOR TONIGHT, DIURNAL CU AND CONVECTION WILL QUICKLY DISSIPATE,  
WITH GOOD SUBSIDENCE EXPECTED ONCE AGAIN. GIVEN THE MORE HUMID  
AIRMASS IN PLACE TODAY, DO NOT EXPECT AS STRONG OF A RIDGE/VALLEY  
SPLIT AS PREVIOUS NIGHTS, BUT DO ANTICIPATE THERE TO STILL BE  
SOME LOCAL EFFECTS PRESENT. KEPT VALLEYS IN THE MID 60S WITH THE  
HIGHER ELEVATIONS IN THE UPPER 60S TO AROUND 70 FOR LOWS. VALLEY  
FOG WILL ALSO BE PRESENT, BUT MUCH LIKE LAST NIGHT, SHOULD REMAIN  
MORE PATCHY AND NON-DENSE IN NATURE.  
 
FOR MONDAY, ISOLATED CONVECTION MAY MAKE ITS WAY FARTHER NORTHWARD  
THROUGH THE CWA DURING THE DAYTIME HOURS WITH BETTER SW FLOW IN  
PLACE ACROSS THE REGION IN THE LOW LEVELS, DUE TO THE HIGH  
PRESSURE CENTER MOVING FAR SE OF THE REGION. MEANWHILE THE UPPER  
LEVEL LOW WILL DISSIPATE AND HAVE LITTLE EFFECT ACROSS THE DEEP  
SOUTH. ONCE AGAIN, NOT EXPECTING MUCH OUT OF ANY CONVECTION THAT  
DOES POP UP ACROSS OUR CWA...MAINLY SHORT LIVED GARDEN VARIETY  
STORMS. HIGHS WILL BE SIMILAR MONDAY TO THAT OF TODAY, AROUND 90  
DEGREES, AND POSSIBLY PUSHING A DEGREE OR TWO ABOVE IN A FEW  
LOCATIONS. WITH THE HUMIDITY TAKEN INTO ACCOUNT, HEAT INDICES WILL  
ONCE AGAIN REACH THE MID AND UPPER 90S. WE WILL CONTINUE TO  
MENTION THE HEAT CONCERNS IN THE HWO AT THIS TIME.  
 
CONVECTION AND CLOUDS WILL ONCE AGAIN DISSIPATE FAIRLY QUICKLY  
HEADING INTO MONDAY NIGHT, WITH TEMPERATURES EXPECTED TO REMAIN  
MILD OVERNIGHT, SIMILAR TO THAT OF TONIGHT. THE RIDGE/VALLEY SPLIT  
WILL CONTINUE TO BE LESS PRESENT WITH THE CONTINUED INFLUX OF  
HUMIDITY, BUT DID LEAVE A FEW DEGREES VARIABILITY IN THERE.  
PATCHY VALLEY FOG WILL ALSO BE POSSIBLE, MAINLY NEAR THE RIVER  
VALLEYS.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 438 PM EDT SUN JUN 17 2018  
 
THERE IS REASONABLY GOOD MODEL AGREEMENT DURING THE PERIOD. AFTER  
SHOWING DIFFERENCES, THE GFS AND ECMWF HAVE NOW COMPROMISED AND  
THEIR SOLUTIONS HAVE MOVED TOWARD EACH OTHER AT THE END OF THE  
WEEK, LENDING A BIT MORE CONFIDENCE TO THE FORECAST. THE GFS  
ENSEMBLE MEAN ALSO SUPPORTS THE OPERATIONAL RUN.  
 
THAT BEING SAID, A SOUTHEAST CONUS MID/UPPER LEVEL RIDGE WILL  
STILL BE IN PLACE AT THE START OF THE PERIOD. THIS WILL KEEP  
PRECIP TO A MINIMUM ON TUESDAY, WITH JUST A SLIGHT CHANCE OF A  
THUNDERSTORM.  
 
THE RIDGE WILL BE WEAKENING AND FLATTENING AS THE WEEK  
PROGRESSES, AS A TROUGH DROPS SOUTHEAST OVER THE NORTHEAST CONUS,  
AND AN UPPER LOW CURRENTLY OVER THE WESTERN CONUS IS FINALLY ON  
THE MOVE ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST. THIS ALLOWS  
A COLD FRONT TO DROP INTO KY FROM THE NORTH AND NORTHEAST. IT IS  
EXPECTED TO STALL NEARBY AND THEN RETURN NORTHEAST AS A WARM FRONT  
BY THE WEEKEND. THE SCENARIO SUPPORTS A HIGHER POP LATE IN THE  
WEEK. WITH BETTER MODEL AGREEMENT, HAVE ALLOWED A LIKELY POP INTO  
THE FORECAST AT TIMES THURSDAY AND FRIDAY, WITH HIGH CHANCE POPS  
INTO THE WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 138 PM EDT SUN JUN 17 2018  
 
VFR CONDITIONS WILL PREVAIL ACROSS THE EASTERN KENTUCKY AIRSPACE  
FOR JUST ABOUT THE ENTIRETY OF THE PERIOD. SOME MVFR OR WORSE FOG  
WILL BE POSSIBLE ONCE AGAIN OVERNIGHT IN VALLEYS, BUT SHOULD HAVE  
NO IMPACT ON THE TAF SITES. A STRAY THUNDERSTORM WILL BE POSSIBLE  
ACROSS PORTIONS OF SOUTHEAST KENTUCKY THIS AFTERNOON, BUT  
COVERAGE AND PROBABILITY STILL LOOK LOW ENOUGH TO MAINTAIN DRY  
FORECASTS FOR EACH TERMINAL. STRAY SHOWERS/THUNDERSTORMS COULD  
EXPAND AS FAR NORTH AS THE MOUNTAIN PARKWAY DURING THE DAY  
TOMORROW, BUT GENERALLY AFTER TAF PERIOD AND STILL WITH VERY LOW  
PROBABILITIES. WINDS WILL BE LIGHT AND VARIABLE AT BELOW 5 KNOTS  
THROUGH THE PERIOD.  
 

 
   
JKL WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...JMW  
LONG TERM...HAL  
AVIATION...GREIF/JMW  
 
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