240  
FXUS63 KLMK 021528  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
1128 AM EDT THU JUL 2 2020  
   
FORECAST UPDATE
 
 
ISSUED AT 1120 AM EDT THU JUL 2 2020  
 
DEWPOINTS HAVE BEEN SLOW TO FALL THIS MORNING AS MOISTURE CONTINUES  
TO POOL NEAR A COUPLE DIFFERENT SFC BOUNDARIES. MID-LEVEL WARMING IS  
EXPECTED, BUT NOT IN TIME TO COMPLETELY SHUT DOWN CONVECTIVE  
POTENTIAL, WHICH WILL MOST LIKELY BE FOCUSED BY DIFFERENTIAL HEATING  
ALONG THE EDGE OF THE DISSIPATING STRATUS SHIELD EXTENDING FROM THE  
PENNYRILE INTO SOUTH CENTRAL KENTUCKY. DECIDED TO GO AHEAD AND  
INCLUDE A 20 POP FOR ISOLATED POP-UPS FROM THE HOOSIER NATIONAL  
FOREST DOWN TOWARD BOWLING GREEN. DEEPER MOISTURE IS LIMITED AND  
WARMING ALOFT SHOULD SHUT THIS DOWN BEFORE SUNSET.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 259 AM EDT THU JUL 2 2020  
 
UPPER LEVEL RIDGING OVER THE CENTRAL US WILL BUILD EASTWARD OVER THE  
OHIO VALLEY BRINGING SOME WELL NEEDED DRY WEATHER TO THE REGION.  
LATEST SURFACE ANALYSIS SHOWS A SUBTLE BOUNDARY STRETCHED W-E ACROSS  
SOUTHERN INDIANA AND CENTRAL KY, WHICH WILL SLOWLY SLIP SOUTHWARD  
THROUGHOUT THE DAY. COULD BE A FOGGY START TO THE DAY FOR THOSE  
LOCATED VALLEYS AND LOW LYING AREAS, BUT ANY FOG WILL BURN OFF  
SHORTLY AFTER SUNRISE GIVING WAY TO MOSTLY SUNNY SKIES WITH LIGHT NE  
WINDS. CAMS ARE SUGGESTING A FEW ISOLATED POP UP SHOWERS POSSIBLE  
THIS AFTERNOON DURING PEAK HEATING, MAINLY SOUTH OF THE WKY PKWY.  
BUT MODEL SOUNDINGS ARE SHOWING A SUBSIDENCE INVERSION FORMING  
BETWEEN 800MB TO 700MB, WHICH SHOULD KEEP CONVECTION RATHER SHALLOW.  
WITH THIS IN MIND AND THE DECREASE IN OVERALL ATMOSPHERIC MOISTURE  
CONTENT, HAVE KEPT ALMOST ALL AREAS DRY TODAY. THICKNESS VALUES  
SUGGEST HIGHS TODAY WILL REACH INTO THE UPPER 80S TO LOWER 90S WITH  
FRIDAY MORNING MINS DIPPING INTO THE MID TO UPPER 60S.  
 
ALSO, AN AIR QUALITY ALERT HAS BEEN ISSUED TODAY FOR PORTIONS OF  
SOUTHERN INDIANA AND A FEW COUNTIES IN NORTH CENTRAL KY INCLUDING  
THE LOUISVILLE METRO VALID UNTIL MIDNIGHT TONIGHT. OZONE IS FORECAST  
TO BE UNHEALTHY FOR SENSITIVE GROUPS INCLUDING SENIORS, CHILDREN,  
AND PEOPLE WITH BREATHING AILMENTS.  
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 304 AM EDT THU JUL 2 2020  
 
FRIDAY THROUGH SUNDAY NIGHT...  
 
OVERALL, NOT MUCH CHANGE IN THE FORECAST THINKING FOR THIS PART OF  
THE FORECAST PERIOD. GLOBAL MODELS REMAIN IN AGREEMENT WITH AN  
UPPER LEVEL RIDGE EXTENDING FROM THE SOUTHWESTERN US THROUGH THE  
PLAINS AND INTO THE WESTERN GREAT LAKES. MODEL SOUNDINGS SHOW A  
VERY STRONG CAP IN PLACE WHICH LOOKS TO KEEP THE AREA DRY ON FRIDAY  
AND SATURDAY. AFTERNOON HIGHS IN THE UPPER 80S TO THE LOWER 90S  
WILL BE SEEN WITH OVERNIGHT LOWS IN THE UPPER 60S TO THE LOWER 70S.  
DEWPOINTS LOOK TO REMAIN IN THE MID-UPPER 60S THROUGH THE PERIOD  
WHICH WILL LIKELY PRODUCE HEAT INDEX READINGS EACH AFTERNOON IN THE  
LOW-MID 90S.  
 
BY THE LATE WEEKEND, THE RIDGE AXIS IS LIKELY TO RETROGRADE A BIT TO  
THE WEST AS A SURFACE AND UPPER LEVEL TROUGH AXIS SETS UP DOWN ALONG  
THE NORTHERN GULF COAST STATES. WE MAY START TO SEE SOME DIURNALLY  
DRIVEN CONVECTION BY SUNDAY AFTERNOON, THOUGH THE BEST CHANCE OF  
THAT LOOKS TO BE ACROSS SOUTHERN KY. GFS IS A BIT MORE ROBUST WITH  
POP CHANCES HERE THAN THE EURO WHICH RESULTS IN THE BLENDED POPS  
REMAIN A BIT TOO HIGH HERE. IF EURO SOLUTIONS TRENDS HOLD, CAN  
EASILY SEE REDUCING POPS CHANCES ESPECIALLY ACROSS SOUTHERN IN AND  
THE NORTHERN HALF OF KY SUNDAY AFTERNOON IN FUTURE FORECASTS. HIGHS  
ON SUNDAY WILL BE HOT WITH HIGHS IN THE UPPER 80S TO THE LOWER 90S  
AGAIN. DEWPOINTS ON SUNDAY MAY BE A BIT HIGHER HERE WITH READINGS IN  
THE UPPER 60S TO NEAR 70. THAT COMBINATION WOULD RESULT IN HEAT  
INDEX READINGS TOPPING OUT IN THE MID 90S.  
 
MONDAY THROUGH WEDNESDAY...  
 
FOR NEXT WEEK, THE MAIN BELT OF WESTERLIES WILL REMAIN WELL TO OUR  
NORTH. THE OVERALL FLOW IN THE FORECASTS HAS BEEN TRENDING TO A  
MUCH LESS AMPLIFIED SOLUTION WITH QUASI ZONAL FLOW EXPECTED ACROSS  
NORTH AMERICA. WITHIN THIS FLOW, SEVERAL PERTURBATIONS WILL LIKELY  
SWING THROUGH WITHIN THE MEAN FLOW. SENSIBLE WEATHER HERE IN THE  
OHIO VALLEY WILL BE TYPICAL OF MID-SUMMER WITH WARM TEMPERATURES AND  
A CHANCE OF AFTERNOON/EVE SHOWERS AND STORMS. OVERALL SHEAR PROFILE  
LOOKS TO REMAIN RATHER WEAK, SO CHANCES OF WELL ORGANIZED CONVECTION  
LOOKS TO BE LOW. FOR NOW, CURRENT FORECAST OF 20-40% POPS EACH  
AFTERNOON LOOKS GOOD. TEMPERATURES THROUGH THE PERIOD LOOK TO BE  
SLIGHTLY ABOVE AVERAGE WITH HIGHS MAINLY IN THE 88-93 DEGREE RANGE.  
 
THURSDAY INTO LATE WEEK...  
 
LATEST GUIDANCE SUGGESTS THAT THE UPPER LEVEL PATTERN OVER THE CONUS  
WILL BECOME A BIT MORE AMPLIFIED LATE NEXT WEEK. THE DATA SUGGESTS  
THAT ANOTHER RIDGE WEST/TROUGH EAST PATTERN IS LIKELY TO SET UP  
ACROSS THE CONUS. THIS WOULD PLACE THE OHIO VALLEY WITHIN A  
NORTHWESTERLY FLOW ALOFT. IN SUCH A PATTERN, NUMEROUS PERTURBATIONS  
WILL LIKELY BE FLOWING THROUGH THE MEAN FLOW BRINGING PERIODS OF  
UNSETTLED WEATHER TO THE REGION. THE EXPECTED CONFIGURATION OF THE  
UPPER PATTERN WOULD FAVOR A COOLER/WETTER PATTERN FOR US, POSSIBLY  
LINGERING INTO THE MIDDLE OF JULY. THIS IS NOT OVERLY SURPRISING  
GIVEN THAT THIS FLOW PATTERN HAS BEEN RATHER DOMINANT FROM THE  
SPRING INTO THIS SUMMER.  
 

 
   
AVIATION
 
(12Z TAF ISSUANCE)  
ISSUED AT 638 AM EDT THU JUL 2 2020  
 
CLEARING SKIES AND BUILDING HIGH PRESSURE HAVE RESULTED IN EXTENSIVE  
VALLEY FOG ACROSS THE EASTERN HALF OF KY AND A MIX OF LOW STRATUS  
AND FOG ACROSS THE WESTERN HALF AND SOUTHERN INDIANA. HNB IS  
CURRENTLY LIFR IN FG WHILE BWG IS IFR IN LOW STRATUS. EXPECT BOTH  
LOCATIONS TO IMPROVE WITHIN AN HOUR OR TWO OF TAF ISSUANCE.  
OTHERWISE, VFR CONDITIONS ARE EXPECTED TO PREVAIL UNDER MOSTLY SUNNY  
SKIES AND LIGHT NE WINDS.  
 

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

 
 

 
 
UPDATE...RAS  
SHORT TERM...CG  
LONG TERM...MJ  
AVIATION...CG  
 
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