007  
FXUS63 KLMK 250036  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
836 PM EDT THU SEP 24 2020  
   
FORECAST UPDATE
 
 
ISSUED AT 835 PM EDT THU SEP 24 2020  
 
FORECAST REMAINS ON TRACK THIS EVENING. ONLY SEEING SOME ISOLATED TO  
SCATTERED LIGHT ECHOES SHOWING UP ON RADAR, SOME OF WHICH MAY NOT  
EVEN BE REACHING THE GROUND. MOST ACTIVITY THROUGH THE OVERNIGHT  
HOURS SHOULD REMAIN SOUTH OF THE OHIO RIVER.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH FRIDAY)  
ISSUED AT 310 PM EDT THU SEP 24 2020  
 
SURFACE ANALYSIS THIS AFTERNOON SHOWS THE REMNANTS OF BETA ARE  
CENTERED OVER THE MS/AL BORDER, WITH THE BULK OF THE RAINFALL  
ASSOCIATED WITH BETA OCCURRING FROM NORTHERN AL UP THROUGH EASTERN  
TN. OVER OUR AREA, CURRENT RADAR IMAGERY SHOWS JUST SOME SCATTERED  
LIGHT SHOWERS MAKING THEIR WAY ACROSS SOUTH-CENTRAL KY.  
ADDITIONALLY, SATELLITE IMAGERY SHOWS AN EXPANSIVE AREA OF CLOUDS  
CONTINUING TO PUSH IN FROM THE SOUTHWEST, RESULTING IN A NOTICEABLE  
TEMPERATURE GRADIENT BETWEEN OUR SOUTHERN KY AREAS (LOWER 60S) AND  
OUR NORTHERN KY/SOUTHERN IN AREAS (LOWER TO MID 70S).  
 
AS WE MOVE INTO TONIGHT, THE REMNANTS OF BETA WILL CONTINUE TO PUSH  
NORTHEAST INTO SOUTHEASTERN TN, RESULTING IN THE BETTER MOISTURE  
THEN BEING CONFINED TO SOUTH- AND EAST-CENTRAL KY. EXPECT TO FIND  
BEST PRECIPITATION CHANCES IN THESE AREAS OVERNIGHT AS WELL AS CAMS  
SUGGEST SOME SCATTERED BANDS OF PRECIPITATION MAY MOVE UP INTO THE  
AREA TONIGHT AND INTO TOMORROW MORNING. ANY PRECIPITATION IS  
EXPECTED TO REMAIN LIGHT HOWEVER, WITH LITTLE IN THE WAY OF QPF.  
OVERNIGHT LOWS ARE FORECAST TO BE SIMILAR TO THIS MORNING, WITH  
TEMPERATURES GENERALLY REMAINING IN THE MID 50S TO AROUND 60.  
 
A SECONDARY SHORTWAVE TROUGH IS THEN PROGGED TO DROP SOUTHEAST INTO  
THE LOWER OH VALLEY FRIDAY AND HELP PUSH THE REMNANTS OF BETA  
EASTWARD INTO THE MID-ATLANTIC REGION. AS THIS OCCURS, PRECIPITATION  
CHANCES ARE EXPECTED TO GRADUALLY EXIT OFF TO THE EAST TOMORROW  
AFTERNOON, AND SKIES WILL BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE  
REGION. HIGH TEMPERATURES FOR TOMORROW ARE FORECAST TO BE IN THE  
LOWER 70S TO NEAR 80, WITH THE COOLER TEMPERATURES EXPECTED OVER  
SOUTHEAST PORTIONS OF OUR FORECAST AREA AS LIGHT RAINFALL AND CLOUD  
COVER WILL LINGER HERE THE LONGEST.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 310 PM EDT THU SEP 24 2020  
 
SHORTWAVE RIDGING BUILDS ACROSS THE AREA FRIDAY NIGHT AND SATURDAY.  
WITH PLENTY OF DRY AIR IN THE MID AND UPPER LEVELS, THIS PERIOD IS  
EXPECTED TO STAY DRY. SOUTHWESTERLY LOW LEVEL FLOW AND THE RIDGING  
ALOFT WILL SUPPORT MILD WEATHER WITH LOWS IN THE UPPER 50S TO LOWER  
60S AND HIGHS AROUND 80. THERE IS A NOTABLE FOG/LOW STRATUS SIGNAL  
IN THE GUIDANCE FOR SATURDAY MORNING, SO HAVE ADDED PATCHY TO AREAS  
OF FOG TO THE FORECAST. LOW LEVEL MOISTURE IS PRESENT ALONG WITH  
VERY LIGHT WINDS IN THE LOWEST 5 KFT AGL. AT LEAST PATCHY DENSE FOG  
LOOKS POSSIBLE SATURDAY MORNING.  
 
AN UPPER LOW WILL WEAKEN/OPEN AS IT MOVES NORTHEAST TOWARD THE AREA  
ON SUNDAY FROM THE LOWER MS VALLEY. THIS FEATURE DOES NOT BRING A  
LOT OF MOISTURE WITH IT. MEANWHILE, A LARGE UPPER TROUGH WILL DIG  
SOUTH OVER THE NORTHERN PLAINS AND UPPER MIDWEST. THE UPPER TROUGH  
DIGS SOUTHEAST OVER THE REGION SUNDAY NIGHT AND MONDAY AND PERSIST  
OVER THE EASTERN CONUS THROUGHOUT NEXT WEEK. LOW CHANCE POPS ARRIVE  
LATE SUNDAY NIGHT/EARLY MONDAY AS MOISTURE DEPTH BEGINS TO INCREASE  
WITH MID-LEVEL PVA. THE ACTUAL COLD FRONT SWEEPS THROUGH MONDAY-  
TUESDAY WITH THE DEEPEST MOISTURE ALONG/BEHIND THE BOUNDARY. RAIN  
SHOWERS WILL LIKELY BE ACCOMPANIED BY GUSTY WINDS, ESPECIALLY POST-  
FRONTAL WITH COLDER AIR FLOODING THE REGION. FAIRLY SIGNIFICANT  
TIMING DIFFERENCES REMAIN BETWEEN THE OPERATIONAL GFS AND ECMWF. THE  
WEATHER IS LIKELY TO DRY OUT BY MIDWEEK BEHIND THE FRONT, BUT  
EXACTLY WHEN THAT OCCURS IS STILL SOMEWHAT UNCERTAIN.  
 
LOOK FOR CHILLY WEATHER MID TO LATE NEXT WEEK WITH THE FIRST FROST  
OF THE SEASON NOT OUT OF THE QUESTION. THURSDAY MORNING LOWS IN THE  
40S ARE LOOKING LIKELY, BUT SHELTERED VALLEYS/LOW SPOTS COULD END UP  
DIPPING INTO THE MID/UPPER 30S. CONFIDENCE IS NOT HIGH AT THIS  
POINT, BUT DEFINITELY SOMETHING TO WATCH.  
 

 
   
AVIATION
 
(00Z TAF ISSUANCE)  
ISSUED AT 707 PM EDT THU SEP 24 2020  
 
MOISTURE ASSOCIATED WITH THE REMNANTS OF BETA WILL CONTINUE TO MOVE  
IN FROM THE SOUTHWEST THROUGH THE FIRST PART OF THE FORECAST PERIOD.  
SOME LIGHT SHOWERS WILL BE POSSIBLE ACROSS SOUTH-CENTRAL KY, BUT  
MORE IMPACTFUL MVFR TO IFR CIGS/VIS WILL BE LIKELY ALONG AND SOUTH  
OF THE WESTERN KENTUCKY/BLUEGRASS PARKWAYS. THE NORTHERN EXTENT OF  
THE MVFR CIGS/VIS REMAIN A BIT UNCERTAIN, BUT IT APPEARS THAT IT  
SHOULD BE ABOVE FUEL-ALTERNATE LEVELS FOR HNB/SDF. DRIER AIR WILL  
WORK IN FROM THE NORTHWEST AFTER SUNRISE TOMORROW AS THE REMNANTS OF  
BETA MOVE OFF TO THE NORTHEAST. GRADUAL LIFTING OF CIGS/VIS CAN BE  
EXPECTED THROUGHOUT THE DAY TOMORROW.  
 

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

 
 

 
 
UPDATE...DM  
SHORT TERM...JML  
LONG TERM...EBW  
AVIATION...DM  
 
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