768  
FXUS63 KLMK 181937  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
337 PM EDT THU JUL 18 2019  
   
SHORT TERM
 
(THIS EVENING THROUGH FRIDAY)  
UPDATED AT 320 PM EDT THU JUL 18 2019  
   
..HOT AND HUMID
 
 
IT'S A HOT, MUGGY AFTERNOON WITH UPPER LEVEL RIDGING SLOWLY BUILDING  
OVER THE MID-MISSISSIPPI AND LOWER OHIO VALLEYS. NOTABLE SCATTERED  
CONVECTION HAS FORMED ALONG A LOW LEVEL CONVERGENCE AXIS FROM  
NORTHERN INDIANA SOUTHEAST THROUGH EASTERN KY. ISOLATED STORMS ARE  
MOST LIKELY IN THE BLUEGRASS REGION OF KY THROUGH SUNSET, WHILE MOST  
OTHERS WILL REMAIN DRY WITH PARTLY TO MOSTLY SUNNY SKIES.  
 
THE EXPANSIVE MID LEVEL CLOUD DECK OVER THE SOUTHWESTERN CWA THIS  
MORNING HAS FINALLY THINNED SOME, AND A LOW LEVEL CU FIELD HAS  
DEVELOPED. BUT MOST OF THE AREA IS SEEING PLENTY OF SUNSHINE, AND  
TEMPERATURES HAVE RISEN INTO THE MID 80S TO LOWER 90S. HEAT INDEX  
VALUES ARE NOW IN THE MID 90S TO LOW 100S AND WILL CREEP UP A BIT  
MORE BEFORE MAXING OUT BETWEEN 20-22Z.  
 
CONVECTION AND THE CU FIELD WILL DIMINISH AFTER SUNSET. IT LOOKS  
QUIET OVERNIGHT WITH LOWS IN THE MID 70S (UPPER 70S IN METRO  
LOUISVILLE).  
 
THE RECORD WARM LOW TEMPERATURES FOR JULY 19 ARE:  
BOWLING GREEN 78 DEGREES IN 1921  
LEXINGTON 75 DEGREES IN 1977, 1926, AND 1876  
LOUISVILLE 80 DEGREES IN 1878  
 
RIDGING ALOFT WILL INCREASE IN STRENGTH ON FRIDAY. LOW LEVEL  
THICKNESSES INCREASE AS WELL, SO EXPECT THE HEAT TO GET TURNED UP.  
HIGHS INTO THE LOW TO MID 90S ARE LIKELY AREA-WIDE WITH UPPER 90S  
POSSIBLE IN LOUISVILLE. SFC DEWPOINTS WILL REMAIN IN THE MID 70S,  
RESULTING IN MAXIMUM HEAT INDICES OF 105-110 DEGREES. THE MULTI-DAY  
HEAT RISK IS ON TRACK, SO THE EXCESSIVE HEAT WARNING WILL CONTINUE  
THROUGH THE WEEKEND.  
 

 
   
LONG TERM
 
(FRIDAY NIGHT THROUGH THURSDAY)  
UPDATED AT 335 PM EDT THU JUL 18 2019  
   
...EXCESSIVE HEAT TO CONTINUE THROUGH PART OF THE WEEKEND
 
 
FRIDAY NIGHT THROUGH MONDAY NIGHT...  
 
MID-LEVEL RIDGE AXIS WILL HOLD SWAY ACROSS THE REGION. THIS WILL  
RESULT IN A DRY FORECAST FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT.  
LOWS FRIDAY NIGHT WILL BE IN THE MID-UPPER 70S WITH SOME OF THE  
URBAN CORRIDORS REMAINING IN THE LOWER 80S. ON SATURDAY WE EXPECT  
ANOTHER HOT AND HUMID DAY. TEMPERATURES IN THE NBM AND THE RAW  
MODELS HAVE COME DOWN SLIGHTLY. HIGHS LOOK TO WARM INTO THE 90-95  
DEGREE RANGE WITH HEAT INDICES IN THE 100-105 RANGE. SOME  
LOCALIZED POCKETS OF 105+ WILL BE POSSIBLE. LOWS SATURDAY NIGHT  
WILL REMAIN IN THE MID-UPPER 70S WITH SOME OF URBAN CENTERS LIKELY  
REMAINING IN THE LOW 80S.  
 
FOR SUNDAY, WILL HAVE TO WATCH AND SEE IF THE EURO'S DEPICTION OF AN  
INVERTED SURFACE TROUGH AXIS DEVELOPS. FOR THE PAST FEW DAYS, THE  
EURO HAS BEEN KEYING ON IN THIS FEATURE AND THAT MAY SPARK A BAND OF  
CONVECTION FROM THE GULF COAST STATES NORTHEASTWARD THROUGH THE TN  
PLATEAU INTO PORTIONS OF CENTRAL AND EAST KY. IF THAT HAPPENS, THEN  
HIGH TEMPERATURES ON SUNDAY MAY END UP BEING A BIT COOLER THAN  
GUIDANCE INDICATES. AS OF NOW, HAVE GOOD CONFIDENCE THAT  
TEMPERATURES WILL TOP OUT IN THE LOWER-MID 90S OVER SOUTHERN IN AND  
PARTS OF NORTH-CENTRAL KY. HOWEVER, HIGHS MAY ONLY REACH THE UPPER  
80S TO AROUND 90 IN THE SOUTHEAST/LAKE CUMBERLAND SECTIONS. IF THIS  
TREND CONTINUES, WE MAY BE ABLE TO DROP THE EXCESSIVE HEAT WARNING  
IN FUTURE PACKAGES.  
 
WELL ADVERTISED SURFACE COLD FRONT LOOKS TO ARRIVE BY SUNDAY EVENING  
AND THE PUSH THROUGH THE REGION DURING THE OVERNIGHT PERIOD. WE  
EXPECT A BAND OF SHOWERS AND THUNDERSTORMS TO ACCOMPANY THE FRONT.  
SOME OF THE STORMS COULD BE ON THE STRONG SIDE AS THEY COME THROUGH.  
THE FRONTAL BOUNDARY WILL SAG SOUTHWARD INTO SOUTHERN KY DURING THE  
DAY ON MONDAY WITH THE GREATEST THREAT OF PRECIPITATION MAINLY SOUTH  
OF THE BG/WK PARKWAYS. TEMPERATURE FORECASTS FOR MONDAY WILL BE  
CHALLENGING WITH THE EXPECTED CLOUDS/FRONT/PRECIPITATION TO BE IN  
THE AREA. OVERALL BLENDED GUIDANCE CONTINUES TO TREND COOLER AND WE  
WILL BE ADJUSTING DOWNWARD AS WELL. HIGHS WILL LIKELY AVERAGE OUT  
IN THE UPPER 70S TO THE LOWER 80S. THE COOLER AND LESS HUMID AIR  
WILL REALLY PUSH INTO THE REGION MONDAY NIGHT AS TEMPERATURES CRASH  
DOWN INTO THE LOWER-MID 60S.  
 
TUESDAY THROUGH THURSDAY...  
 
SURFACE COLD FRONT IS FORECAST TO BE SOUTH OF THE REGION BY TUESDAY  
MORNING. THE FRONT SHOULD CONTINUE ITS SOUTHWARD TREK THROUGH THE  
END OF THE WEEK. ALOFT, WE'LL SEE A COOL NORTHWESTERLY FLOW WHICH  
WILL KEEP TEMPERATURES SLIGHTLY BELOW SEASONAL NORMALS, BUT WITH A  
LOT LESS HUMIDITY THAN WHAT WE'VE SEEN OF LATE. HIGHS DURING THE  
DAY WILL LIKELY TOP OUT IN THE 80-85 DEGREE RANGE WITH OVERNIGHT  
LOWS IN THE UPPER 50S TO THE LOWER 60S.  
 

 
   
AVIATION
 
(18Z TAF ISSUANCE)  
UPDATED AT 138 PM EDT THU JUL 18 2019  
 
IT WILL REMAIN WARM AND VERY HUMID WITH PREVAILING VFR CONDITIONS  
THIS TAF PERIOD. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL INCREASE  
IN STRENGTH INTO FRIDAY. WSW WINDS OF 6-10 KTS THIS AFTERNOON WILL  
BACK OUT OF THE SW AND DIMINISH SLIGHTLY AFTER SUNSET.  
 
THE NORTHERN TAF SITES CAN EXPECT PARTLY TO MOSTLY SUNNY SKIES THIS  
AFTERNOON, BUT A BKN MID LEVEL CLOUD DECK WILL CONTINUE MOVING FROM  
NW TO SE OVER BWG. BWG WILL SEE CLEARING BY THIS EVENING. PRIMARILY  
SCT HIGH CLOUDS ARE EXPECTED TONIGHT AND FRIDAY, BUT A BKN LOW  
STRATUS DECK COULD IMPACT LEX FOR A FEW HOURS FRIDAY MORNING.  
 

 
   
LMK WATCHES/WARNINGS/ADVISORIES
 
 
IN...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT /7 PM CDT/ SUNDAY FOR  
INZ076>079-083-084-089>092.  
 
KY...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT /7 PM CDT/ SUNDAY FOR  
KYZ023>043-045>049-053>057-061>067-070>078-081-082.  
 

 
 

 
 
SHORT TERM...EBW  
LONG TERM...MJ  
AVIATION...EBW  
 
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