207  
FXUS63 KJKL 261500  
AFDJKL  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSON KY  
1100 AM EDT THU APR 26 2018  
   
UPDATE
 
 
ISSUED AT 1100 AM EDT THU APR 26 2018  
 
LOW PRESSURE OVER NORTHERN MS THIS MORNING WILL MOVE EAST TODAY,  
BEFORE TURNING NORTHEAST THIS EVENING. RAIN CURRENTLY OVER TN WILL  
BE SLOW TO ADVANCE NORTH TODAY, BUT WILL PIVOT NORTH ACROSS THE  
SOUTHEAST PART OF THE FORECAST AREA BY LATE AFTERNOON OR EVENING  
AS THE LOW PRESSURE SYSTEM MOVES EAST AND BEGINS IT NORTHEAST  
TURN. HAVE UPDATED THE FORECAST WITH LATEST OBSERVATIONAL TRENDS  
AND SHORT TERM GUIDANCE. MAIN CHANGE IS TO SLIGHTLY SLOW THE  
NORTHWARD ADVANCE OF RAIN CHANCES THIS AFTERNOON.  
 
UPDATE ISSUED AT 755 AM EDT THU APR 26 2018  
 
FOG AND LOW CLOUDS WERE AFFECTING MUCH OF THE AREA EARLY THIS  
MORNING, BUT WILL DISSIPATE DURING THE MORNING. HOWEVER, HIGHER  
CLOUDS ASSOCIATED WITH THE NEXT WEATHER SYSTEM WILL BE ON THE WAY  
IN AND PROBABLY KEEP SUNSHINE LIMITED TODAY. OTHERWISE, EARLY  
MORNING TEMPERATURES HAVE BEEN BLENDED INTO THE FORECAST, WITH NO  
REAL IMPACT.  
 

 
   
SHORT TERM
 
(TODAY THROUGH FRIDAY)  
ISSUED AT 419 AM EDT THU APR 26 2018  
 
THE LOW PRESSURE SYSTEM WHICH BROUGHT RAIN TO THE AREA OVER THE  
LAST FEW DAYS HAS FINALLY DEPARTED TO THE NORTHEAST. THERE IS NO  
APPRECIABLE CHANGE IN AIR MASS IN ITS WAKE, AND WITH CLOUDS TRYING  
TO BREAK UP AT TIMES, THE COOLING OF THE ALREADY DAMP SURFACE AIR  
HAS LED TO FOG DEVELOPMENT IN MANY AREAS. THE FOG SHOULD DISSIPATE  
ON THURSDAY MORNING AS TEMPERATURES START TO CLIMB. HOWEVER,  
CLOUDS WITH THE NEXT WEATHER SYSTEM WILL BE ON THE WAY IN, AND  
ONLY ALLOW FOR VERY LIMITED SUNSHINE.  
 
EARLY THIS MORNING, THIS NEXT LOW PRESSURE SYSTEM WAS CENTERED  
OVER AR AND NORTHERN MS. IT WILL TRACK EASTWARD, PASSING TO OUR  
SOUTH LATE TODAY AND THIS EVENING. MODELS HAVE SETTLED ON A  
SOLUTION BRINGING LIGHT RAIN TO OUR SOUTHERN AND SOUTHEASTERN  
COUNTIES, WITH MORE SIGNIFICANT RAIN FURTHER TO THE SOUTH AND  
EAST. HAVE CONTINUED WITH A 60-70% POP NEAR THE TN AND VA BORDERS,  
TAPERING TO LESS THAN 20% NORTH OF I-64. THIS SYSTEM TURNS  
NORTHEAST ON THE EAST SIDE OF THE APPALACHIANS AS IT PULLS AWAY  
TONIGHT.  
 
MOST OF THE FORECAST AREA CAN THEN EXPECT A DRY DAY ON FRIDAY.  
WITH NO APPRECIABLE CHANGE IN AIR MASS, AND CLOUDS BREAKING UP,  
TEMPERATURES SHOULD BE MILDER. A COLD FRONT WILL APPROACH FROM THE  
NORTHWEST LATE IN THE DAY. MOISTURE WILL BE VERY LIMITED ALONG THE  
FRONT, AND THE PROSPECT FOR PRECIP IS SMALL. THE GFS DOES HAVE  
SOME SHOWERS DEVELOPING IN SHALLOW CONVECTION IN OUR NORTHWEST  
COUNTIES TOWARD EVENING, BUT THE NAM AND ECMWF KEEP PRECIP TO OUR  
NORTH. IN A COMPROMISE, HAVE USED JUST A 20% POP NORTH OF I-64  
LATE IN THE DAY.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 419 AM EDT THU APR 26 2018  
 
LARGE SCALE TROUGHING WILL BE IN PLACE ACROSS THE OHIO VALLEY TO  
START OFF THE PERIOD FRIDAY NIGHT INTO SATURDAY, DEEPENING AS A  
CLOSED LOW DEVELOPS AND ROTATES THROUGH THE GREAT LAKES REGION. THIS  
LOW IS EXPECTED TO EXIT EAST OF THE GREAT LAKES BY SUNDAY  
EVENING/NIGHT, WITH RISING HEIGHTS TAKING HOLD ACROSS KENTUCKY AS  
UPPER LEVEL RIDGING BEGINS TO MOVE INTO PLACE. THIS RIDGING WILL  
ENCOMPASS MUCH OF THE EASTERN CONUS BY TUESDAY. BOTH THE ECMWF AND  
GFS ARE IN GOOD AGREEMENT ABOUT LARGE SCALE TROUGHING ACROSS THE  
WESTERN HALF OF THE CONUS DURING THIS TIME, WITH A UPPER LEVEL LOW  
DEVELOPING WITHIN THE TROUGH AXIS AND QUICKLY ROTATING SE,  
DRASTICALLY LOWERING HEIGHTS ACROSS THE WESTERN MOST STATES. AS THIS  
CLOSED LOW MAKES THE SHIFT NORTHEASTWARD TOWARDS THE CENTRAL PLAINS  
DURING THE DAY WEDNESDAY, HEIGHTS ACROSS THE CENTRAL U.S. WILL LOWER  
QUICKLY. THE CLOSED LOW WILL EVENTUALLY WEAKEN AND BECOME ABSORBED  
INTO THE TROUGH AGAIN, BUT NOT BEFORE HEIGHTS BEGIN LOWERING ACROSS  
KENTUCKY DURING THE DAY THURSDAY.  
 
AS FOR SENSIBLE WEATHER, AN AREA OF PRECIPITATION WILL BE ASSOCIATED  
WITH A SURFACE LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES  
FRIDAY NIGHT AND SATURDAY. WHILE THERE IS STILL SOME UNCERTAINTY ON  
THE EXACT EXPANSE AND TRACK OF THIS PRECIPITATION SWATH, THE ECMWF,  
NAM80, AND ECMWF SHOW THE MAIN AREA OF PRECIP NORTH OF THE OHIO  
RIVER, EXPANDING INTO FAR SE KY DURING SATURDAY AFTERNOON UNDER MORE  
W TO NW FLOW. AS SUCH, KEPT MENTION OF POPS OUT OF CWA FRIDAY NIGHT  
THROUGH THE FIRST PART OF THE DAY SATURDAY, WITH JUST SLIGHT CHANCE  
POPS FOR SATURDAY AFTERNOON.  
 
AFTER THIS SYSTEM MOVES OUT, AN EXPANSIVE AREA OF SURFACE HIGH  
PRESSURE WILL TAKE HOLD ACROSS THE REGION FOR THE REMAINDER OF THE  
WEEKEND AND WELL INTO MID WEEK NEXT WEEK. EACH DAY THAT RIDGING AND  
HIGH PRESSURE ARE IN PLACE MEANS THE AIRMASS WILL MODIFY WARMER,  
ESPECIALLY AS SOUTHERLY WINDS SET IN. HIGHS ON SUNDAY WILL BE AROUND  
60 DEGREES UNDER NW FLOW...HOWEVER BY MONDAY SUNNY CONDITIONS  
COMBINED WITH A MORE SRLY FLOW WILL BOOST AFTERNOON TEMPS INTO THE  
LOW 70S IN MANY LOCATIONS. IN FACT, CURRENT FORECAST HAS  
TEMPERATURES POSSIBLY REACHING 80 DEGREES BY TUESDAY IN A FEW  
LOCATIONS. THE SAME WILL BE TRUE FOR WEDNESDAY AS WELL.  
 
BY LATE WEDNESDAY AFTERNOON AND INTO THURSDAY, CLOUDS WILL BE ON THE  
INCREASE AS A COLD FRONT BEGINS TO NEAR THE REGION FROM THE WEST,  
FOLLOWING THE GREATEST HEIGHT FALLS ALOFT. DESPITE CLOUDS, THE  
STRONG SRLY FLOW WILL STILL BOOST TEMPS TO NEAR 80 FOR HIGHS ON  
THURSDAY. A FEW POP UP SHOWERS WILL BE POSSIBLE AS EARLY AS  
WEDNESDAY AFTERNOON AHEAD OF THIS SYSTEM, SO KEPT IN THE SLIGHT  
CHANCE POPS THAT THE SUPERBLEND GAVE OVER PORTIONS OF THE WESTERN  
CWA DURING THIS TIME. THESE WILL QUICKLY DIMINISH IN THE EVENING.  
THE MAIN LINE OF PRECIP ASSOCIATED WITH THIS STORM SYSTEM WILL THEN  
BEGIN IMPACTING WESTERN KENTUCKY DURING THE DAY THURSDAY. THIS WILL  
RESULT IN GENERALLY SLIGHT CHANCE POPS ACROSS OUR WESTERN CWA  
THROUGHOUT THE DAY, INCREASING JUST PAST THE FORECAST PERIOD AS THE  
SYSTEM CONTINUES ON ITS EASTWARD TRACK TOWARDS JKL.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)  
ISSUED AT 755 AM EDT THU APR 26 2018  
 
FOG AND LOW CLOUDS WERE AFFECTING MOST OF THE AREA EARLY THIS  
MORNING. THEY ARE EXPECTED TO DISSIPATE BY LATE MORNING, GIVING  
WAY TO VFR CONDITIONS. CLOUDS WILL THEN LOWER AGAIN OVER  
SOUTHERN AND SOUTHEASTERN KENTUCKY DURING THE AFTERNOON, WITH RAIN  
LIKELY DEVELOPING. CONDITIONS SHOULD BE LOW END VFR BY LATE IN  
THE DAY, PERHAPS HITTING MVFR IN SOME LOCATIONS. THE LIGHT RAIN  
AND BORDERLINE VFR/MVFR CONDITIONS SHOULD THEN LAST INTO THE  
EVENING IN SOUTHEAST KENTUCKY, PROBABLY LOWERING INTO MVFR  
TERRITORY OVERNIGHT. MEANWHILE, HIGHER CEILINGS AND DRY WEATHER  
SHOULD PREVAIL FURTHER TO THE NORTHWEST.  
 

 
   
JKL WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
UPDATE...SBH  
SHORT TERM...HAL  
LONG TERM...JMW  
AVIATION...HAL  
 
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