934  
FXUS63 KJKL 181433  
AFDJKL  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSON KY  
1033 AM EDT SAT AUG 18 2018  
   
UPDATE
 
 
ISSUED AT 1033 AM EDT SAT AUG 18 2018  
 
UPDATED POPS A TOUCH BASED ON CURRENT RADAR TRENDS AS WELL AS HRRR  
AND NAM RUNS SHOWING THE BAND OF SHOWERS PROGRESSING TO THE EAST.  
THE AREAS THAT WILL SEE THE HEAVIEST RAINFALL ARE IN THE FAR  
EAST, FROM BREATHITT COUNTY TO PIKE COUNTY, THROUGH THE FIRST PART  
OF THE AFTERNOON. CONVECTION LOOKS TO REDEVELOP LATER THIS  
AFTERNOON INTO THE EVENING, MAINLY IN THE CUMBERLAND BASIN AND  
BLUEGRASS REGIONS AS SEEN BY THE LATEST RUN OF THE HRRR. THERE  
HAVE BEEN NO MAJOR ISSUES WITH HYDRO YET, AS GUIDANCE IS WELL OVER  
TWO INCHES AND THERE HAVE ONLY BEEN A COUPLE AREAS THAT HAVE SEEN  
AROUND AN INCH THIS MORNING. WILL CONTINUE TO MONITOR THE  
DEVELOPMENT OF THE CONVECTION AND THE POTENTIAL FOR HYDRO CONCERNS  
AS THE DAY PROGRESSES.  
 
UPDATE ISSUED AT 649 AM EDT SAT AUG 18 2018  
 
A BAND OF MODERATE TO AT TIMES HEAVY RAIN SHOWERS CONTINUES TO  
MOVE AND EXPAND ACROSS SOUTHEAST KENTUCKY THIS MORNING. MOST  
LOCATIONS ARE SEEING A QUARTER OF AN INCH OR LESS AN HOUR WITH  
EMBEDDED HIGHER AMOUNTS POSSIBLE. THE LATEST INFORMATION FROM THE  
SPC MESOANALYSIS PAGE SHOWS THE DIVERGENCE ALOFT FROM THE JET  
STREAK AND THE VAD WIND PROFILE AT MRX SHOWS A 25 KNOT LOW LEVEL  
JET TALKED ABOUT IN THE SHORT TERM DISCUSSION. GIVEN THIS RAISED  
POPS IN PORTIONS OF THE SOUTHEAST INTO THE CATEGORICAL RANGE  
THROUGH THE MORNING HOURS. DID KEEP THE ISOLATED MENTION OF  
THUNDER BUT MUCH OF THIS WILL PROBABLY BE MOSTLY BE RAIN SHOWERS  
THROUGH MORNING. UPDATED OTHER GRIDS TO REFLECT THE LATEST OBS  
AND TRENDS.  
 

 
   
SHORT TERM
 
(TODAY THROUGH SUNDAY)  
ISSUED AT 400 AM EDT SAT AUG 18 2018  
 
THE MORNING SURFACE ANALYSIS SHOWS A SURFACE BOUNDARY REMAINS JUST  
TO THE NORTH ALONG AND NEAR THE OHIO RIVER THIS MORNING. WE HAVE  
SEEN MAINLY ISOLATED TO SCATTERED CONVECTION FORM ALONG AND SOUTH  
OF THIS BOUNDARY NEAR THE BLUEGRASS AND PORTIONS OF CENTRAL  
KENTUCKY. MEANWHILE, THERE IS A WEAKER AREA OF LOW PRESSURE IN THE  
TENNESSEE VALLEY THIS MORNING. THIS FEATURE ALONG WITH INCREASING  
850MB JET AROUND 25 TO 30 KNOTS AND NEARBY EXIT REGION OF A 300MB  
JET IS BEGINNING TO ENHANCE THE CONVECTION MOVING NORTH AND EAST  
OUT OF PORTIONS OF MIDDLE TENNESSEE. GIVEN THIS HAVE INCREASED  
COVERAGE IN PORTIONS OF SOUTHEAST KENTUCKY THROUGH THE MORNING TO  
BETTER PORTRAY THIS FEATURE IN THE POP GRIDS. RIGHT NOW MOST OF  
THIS HAS BEEN IN THE FORM OF SHOWERS, BUT REMAINS SOME CHANCES OF  
AN ISOLATED STORM AND HAVE KEPT THIS MENTIONED IN THE WX GRIDS  
THROUGH THE MORNING. GIVEN THE DEEP LAYER MOISTURE (PWATS STILL  
NEARING 2 INCHES IN SOME CASES) WILL CONTINUE TO MONITOR THE FLOOD  
THREAT IN THIS ACTIVITY, BUT THINK THIS WILL REMAIN ISOLATED AT  
THIS TIME. GIVEN THIS WILL HOLD OFF ON FLASH FLOOD WATCH AND  
CONTINUE TO CARRY IN THE HWO.  
 
LATER TODAY THE PREVIOUSLY MENTION FRONT WILL CONTINUE TO TRACK  
CLOSER TO EASTERN KENTUCKY AND THE 500MB TROUGH WILL CONTINUE TO  
PROVIDE HEIGHT FALLS. THIS WILL BRING A RESURGENCE IN POPS ACROSS  
THE BLUEGRASS AND HAVE TRIED TO PORTRAY THIS IN THE GRIDS.  
HOWEVER, KEEP MOST OF THE AREA IN AT LEAST LIKELY POPS THROUGH  
MUCH OF THE DAY, BEFORE WANING THE POPS THROUGH THE LATE AFTERNOON  
AND EVENING AS THE FRONT DIVES ACROSS THE AREA. WHAT IS LEFT OF  
THIS BOUNDARY WILL LINGER INTO SUNDAY AND GIVE WAY TO SOME SHOWERS  
AND THUNDERSTORM POTENTIAL IN THE FAR SOUTHEAST. THIS ACTIVITY  
WILL WANE THROUGH THE AFTERNOON AS THE BOUNDARY PUSHES INTO THE  
TENNESSEE VALLEY BY SUNDAY EVENING.  
   
LONG TERM
 
(SUNDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 417 AM EDT SAT AUG 18 2018  
 
A WEAKENING UPPER LEVEL TROUGH WILL BE SLOWLY DEPARTING TO OUR EAST  
SUNDAY NIGHT, AS ANOTHER UPPER LEVEL TROUGH OVER THE CENTRAL PLAINS  
HEADS EAST TOWARD US. AT THE SURFACE, A STALLED FRONTAL BOUNDARY IS  
EXPECTED TO BE LAID OUT EAST/WEST THROUGH TN. ONE OF THE FEW MODEL  
DISAGREEMENTS OF SIGNIFICANCE DURING THE PERIOD CONCERNS  
PRECIPITATION ON SUNDAY NIGHT. THE NAM CONTINUES TO GENERATE PRECIP  
OVER KY AS THE BOUNDARY LIFTS NORTHWARD AS A WARM FRONT, WHILE THE  
GFS AND ECMWF BOTH HOLD PRECIP TO OUR SOUTH. BEING IN THE LATER  
PORTION OF THE NAM MODEL RUN, PREFERENCE IS GIVEN TO THE GFS AND  
ECMWF, AND NOTHING MORE THAN 20% POP IS BEING USED IN SUNDAY NIGHT'S  
FORECAST AT THIS POINT.  
 
THE NEXT APPROACHING UPPER LEVEL TROUGH WILL SUPPORT THE DEVELOPMENT  
OF A SURFACE LOW WHICH WILL TRACK NORTHEAST ACROSS THE MIDWEST ON  
MONDAY AND TUESDAY. THIS WILL INITIALLY SEND THE WARM FRONT NORTH OF  
OUR AREA, AND PUT US INTO A FEED OF WARM AND MOIST AIR COMING IN  
FROM THE SOUTH AND SOUTHWEST. COUPLED WITH UPPER LEVEL SUPPORT FROM  
THE APPROACHING TROUGH, THIS WILL BRING A RETURN OF SHOWERS AND  
THUNDERSTORMS. THE ACTIVITY IS EXPECTED TO PEAK ON TUESDAY WITH THE  
ARRIVAL OF THE UPPER TROUGH AXIS AND A COLD FRONT TRAILING FROM THE  
SURFACE LOW PASSING TO OUR NORTH.  
 
PRECIP SHOULD TAPER OFF TUESDAY NIGHT AND WEDNESDAY AS SURFACE HIGH  
PRESSURE BEHIND THE COLD FRONT BUILDS IN FROM THE WEST WITH DRIER  
AIR. IN FACT, FORECAST SOUNDINGS SHOW MUCH MORE COMFORTABLE HUMIDITY  
LEVELS TO FINISH OUT THE WORK WEEK, WITH DRY AIR MIX DOWN RESULTING  
IN DEW POINTS IN THE 50S.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)  
ISSUED AT 659 AM EDT SAT AUG 18 2018  
 
WE HAVE SEEN A BAND OF RAIN SHOWERS SPREAD ACROSS PORTIONS OF  
SOUTHEAST KENTUCKY THIS MORNING AS FRONT CLOSE IN CLOSER TO THE  
REGION AND UPPER LEVEL WAVE MOVES ACROSS THE REGION. SOME OF  
THESE COULD BE MODERATE TO HEAVY AT TIMES THROUGH THE MORNING, BUT  
WILL GENERALLY KEEP VIS UNRESTRICTED AT TAF SITES FOR NOW GIVEN  
THE ISOLATED NATURE OF THE HEAVIER ACTIVITY. DO HAVE MOST SITES  
EITHER IN MVFR OR CLOSE THROUGH MUCH OF THE DAY FOR CIGS. HOWEVER,  
WOULD EXPECT SITES TO SEE VARYING RESTRICTIONS DUE TO RAIN  
SHOWERS. WE WILL SEE IMPROVEMENTS TO THE CIGS AND VIS THROUGH THE  
LATE AFTERNOON AND EVENING AS A FRONT SLOWLY PUSHES SOUTHWARD. THE  
WINDS THROUGH THE TAF PERIOD WILL REMAIN LIGHT, BUT YOU CAN'T  
RULE OUT A HIGHER GUST WITH STRONGER THUNDERSTORMS.  
 

 
   
JKL WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
UPDATE...CGAL  
SHORT TERM...DJ  
LONG TERM...HAL  
AVIATION...DJ  
 
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