489  
FXUS63 KLMK 201403  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
1003 AM EDT WED SEP 20 2017  
   
..FORECAST UPDATE
 
 
ISSUED AT 958 AM EDT WED SEP 20 2017  
 
FOG HAS MOSTLY DISSIPATED ACROSS CENTRAL KENTUCKY, EXCEPT FOR THE  
DEEPER RIVER VALLEYS. OVER SOUTHERN INDIANA, COVERAGE IS STILL  
LIMITED, BUT FOG IS MOST PRONOUNCED ALONG THE I-65 CORRIDOR WHERE IT  
REMAINS BANKED UP AGAINST THE KNOBS TO THE WEST. EXPECT THE  
DISSIPATING TREND TO CONTINUE, AND SHOULD BE ABLE TO UPDATE TO CLEAN  
UP THE MORNING FOG WORDING IN FORECASTS WITHIN THE NEXT HOUR.  
 
ISSUED AT 643 AM EDT WED SEP 20 2017  
 
OBSERVATIONS HAVE RECENTLY IMPROVED IN MANY SPOTS AND MOST OF THE  
DENSE FOG SEEMS TO BE CONFINED TO THE RIVER VALLEYS. WILL CONSIDER  
CANCELLING THE DENSE FOG ADVISORY AND LEANING ON A SPECIAL WEATHER  
STATEMENT.  
   
SHORT TERM (NOW THROUGH THURSDAY)
 
 
ISSUED AT 315 AM EDT WED SEP 20 2017  
 
TODAY...  
 
GOES 16 SATELLITE IMAGERY IS SHOWING FOG BEGINNING TO SHOW UP NICELY  
OVER MUCH OF THE CWA, ESPECIALLY IN AND AROUND THE RIVER VALLEYS.  
PLAN ON ISSUING A DENSE FOG ADVISORY FOR MOST OF THE CWA MINUS A  
TIER OR TWO OF COUNTIES IN OUR FAR WEST. FOG SHOULD BURN OFF A  
COUPLE HOURS AFTER SUNRISE.  
 
AN ELONGATED UPPER RIDGE AXIS WILL BECOME MORE PROMINENT FROM THE  
SOUTHERN PLAINS UP THROUGH THE GREAT LAKES TODAY. MEANWHILE,  
LINGERING MOISTURE ASSOCIATED WITH A WEAK UPPER LOW OVER CENTRAL OH  
WILL ONLY VERY SLOWLY PUSH EAST. MODELS SUGGEST THAT A STRAY SHOWER  
OR TWO COULD OCCUR, BUT COVERAGE AND CONFIDENCE IN THIS OCCURRING IN  
ANY ONE SPOT IS TOO LOW TO WARRANT ANY MENTIONABLE PRECIP CHANCES.  
UNDER PLENTY OF SUNSHINE, HIGHS SHOULD BE ABLE TO WARM TO THE MID  
AND UPPER 80S TODAY, ALONG AND WEST OF I-65. DEPENDING ON CLOUD  
COVER AND FOG IN THE EAST, HIGH WILL BE MORE CONFINED TO THE MID 80S.  
 
TONIGHT - THURSDAY...  
 
EXPECT IT TO BE ANOTHER FOGGY NIGHT TONIGHT GIVEN MOSTLY CLEAR SKIES  
AND CALM WINDS. ONE LIMITING FACTOR WILL BE UPPER SKY COVER THAT  
COULD SPOIL THE BEST RADIATIONAL COOLING CONDITIONS. WILL MAINLY  
MENTION PATCHY FOG FOR THIS REASON.  
 
UPPER RIDGE STRENGTHENS AND BECOMES A BIT MORE ESTABLISHED OVER THE  
AREA TONIGHT INTO THURSDAY. THERE HAS BEEN A CONSISTENT SIGNAL IN  
THE MODEL DATA FOR AN ISOLATED SHOWER OR STORM ON THURSDAY.  
RELUCTANT TO MENTION ANY POPS GIVEN THE PATTERN RECOGNITION WITH A  
STRENGTHENING UPPER RIDGE, BUT THERE WILL BE SOME INSTABILITY.  
EITHER WAY, MOST FOLKS WILL BE CONTINUED DRY AND WELL ABOVE NORMAL  
FOR TEMPS. LOOK FOR MID AND UPPER 80S WITH A FEW WESTERN SPOTS  
POSSIBLY TOUCHING 90.  
   
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)
 
 
ISSUED AT 315 AM EDT WED SEP 20 2017  
 
STRONG UPPER RIDGING WILL HOLD OVER THE AREA THROUGH THE WEEKEND AND  
INTO EARLY NEXT WEEK, KEEPING OUR CONDITIONS MOSTLY DRY AND TEMPS  
ABOVE NORMAL. MODELS CONTINUE TO SHOW SOME HINTS OF ISOLATED SHOWER  
OR STORM ACTIVITY AT TIMES DURING THIS STRETCH, HOWEVER THE OVERALL  
PATTERN SUGGEST QUITE A BIT OF SUBSIDENCE AND THE LACK OF ANY  
NOTICEABLE TRIGGERING MECHANISMS. ALSO, A LOOK AT FORECAST SOUNDINGS  
SHOWS MORE OF A SUBSIDENCE INVERSION THAN IT DID YESTERDAY. SO, WILL  
CONTINUE THE IDEA OF KEEPING ANY PRECIP CHANCES SILENT.  
 
HIGHS ARE EXPECTED TO BE MOSTLY IN THE UPPER 80S AS WE END THE WORK  
WEEK AND HEAD INTO THE WEEKEND. A FEW SPOTS COULD TOUCH 90, MOST  
LIKELY IN OUR WESTERN CWA. AS WE END THE WEEKEND AND START THE NEW  
WORK WEEK, THE UPPER RIDGE ISN'T QUITE AS STRONG SO TEMPS ARE  
EXPECTED TO BE MORE IN THE MID TO UPPER 80S. THESE VALUES ARE AROUND  
10 DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR.  
 
LOWS WILL RANGE IN THE MID TO UPPER 60S AS WE MOVE TOWARD THE  
WEEKEND, HOWEVER WILL DROP INTO THE LOW TO MID 60S THROUGH THE  
WEEKEND AND INTO EARLY NEXT WEEK.  
 

 
   
AVIATION (12Z TAF UPDATE)
 
 
ISSUED AT 650 AM EDT WED SEP 20 2017  
 
MAIN CONCERN THIS MORNING WILL MAINLY DEAL WITH FOG AT THE TAF  
SITES. THINGS HAVE RECENTLY IMPROVED, SO WILL START THE TAFS OUT  
MORE OPTIMISTIC AND MOSTLY IN THE MVFR RANGE. AFTER FOG BURNS OFF,  
IT SHOULD BE A PRETTY QUIET DAY WITH A FEW-SCT CU AND LIGHT AND  
VARIABLE WINDS. SOME FOG DEVELOPMENT IS POSSIBLE AGAIN TONIGHT.  
 

 
   
LMK WATCHES/WARNINGS/ADVISORIES
 
 
KY...NONE.  
IN...NONE.  

 
 

 
 
UPDATE.........RAS  
SHORT TERM.....BJS  
LONG TERM......BJS  
AVIATION.......BJS  
 
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