630  
FXUS63 KLMK 072319  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
719 PM EDT TUE JUL 7 2020  
   
..UPDATED FORECAST AND AVIATION DISCUSSIONS
 
 
   
FORECAST UPDATE
 
 
ISSUED AT 700 PM EDT TUE JUL 7 2020  
 
POP GUIDANCE THE NEXT FEW HOURS IS FOCUSED ON SOUTHERN IN AND  
SOUTHERN KY FOR NEW DEVELOPMENT, BUT WANDERING BOUNDARIES FROM  
EARLIER STORMS AND RESIDUAL INSTABILITY FROM PEAK HEATING STILL CAN  
BRING SOME ISOLATED DEVELOPMENT IN THE REGION IN BETWEEN OVER THE  
NEXT FEW HOURS. HAVE UPDATED THE FORECAST TO REMOVE THE AFTERNOON  
WORDING.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH WEDNESDAY)  
ISSUED AT 245 PM EDT TUE JUL 7 2020  
   
..ANOTHER HOT/MUGGY DAY WEDNESDAY WITH PEAK HEAT INDICES NEAR 100
 
   
..SCATTERED PM STORMS CAPABLE OF LOCALIZED FLOODING/WIND
 
 
WIDELY SCATTERED STORMS DEVELOPED RIGHT ON CUE THIS AFTERNOON AND  
WILL CONTINUE FOR SEVERAL HOURS BEFORE DISSIPATING THIS EVENING.  
WITH SBCAPE AROUND 3000 J/KG, DCAPE OF 800-1000 J/KG, AND PWAT OF  
1.8", LOCALLY TORRENTIAL DOWNPOURS AND BRIEFLY GUSTY WINDS WILL BE  
THE MAIN CONCERN WITH THE STRONGER CELLS.  
 
WE'LL HAVE ANOTHER WARM AND MUGGY NIGHT TONIGHT WITH LITTLE TO NO  
BREEZE IN A FAIRLY FLAT SURFACE PRESSURE PATTERN. SOME PATCHY FOG  
WILL BE POSSIBLE AROUND DAWN IN THE HUMID, STAGNANT AIR MASS.  
 
ANOTHER HOT AND MUGGY DAY CAN BE EXPECTED ON WEDNESDAY WITH  
AFTERNOON HIGHS ONCE AGAIN IN THE 90-95 DEGREE RANGE AND HEAT INDEX  
READINGS PEAKING NEAR 100 AS THE STUBBORN SUMMERTIME AIR MASS  
REMAINS IN PLACE. AGAIN IT'S DIFFICULT TO FIND A SIGNIFICANT  
TRIGGER, SO STORM DEVELOPMENT WILL OCCUR ON VARIOUS SUBTLE  
BOUNDARIES SIMILAR TO WHAT WE'VE SEEN RECENTLY. MODEL SOLUTIONS  
ACTUALLY SHOW JUST ISOLATED ACTIVITY.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 247 PM EDT TUE JUL 7 2020  
 
THE LONG TERM BEGINS UNIMPRESSIVE. UPPER LEVEL FLOW REMAINS WELL  
NORTH OF THE OHIO VALLEY. A SURFACE LOW CONTINUES TO GATHER MOISTURE  
OVER THE SOUTHEASTERN UNITED STATES, AND WITH SOUTHERN INDIANA AND  
CENTRAL KENTUCKY REMAINING WITHIN THIS AREA OF MOISTURE WITH NO  
STEERING FLOW ALOFT, CONDITIONS WILL CONTINUE UNCHANGED. HIGH  
TEMPERATURES WILL REACH INTO THE 90S WITH AFTERNOON AND EVENING  
DIURNALLY DRIVEN ISOLATED TO SCATTERED THUNDERSTORMS. PRECIPITABLE  
WATER VALUES REMAIN IN THE 1.6 TO 1.8 INCH RANGE. THIS WILL LIKELY  
RESULT IN STORMS THAT PRODUCE HEAVY RAINFALL, AND WITH NO STEERING  
WINDS, STORMS WILL BE SLOW MOVING. THIS KEEPS ISOLATED FLOODING  
RISKS IN THE AREA.  
 
THURSDAY NIGHT INTO FRIDAY, THE OVERALL UPPER FLOW BEGINS TO CHANGE  
OVER THE MIDWEST AS A TROUGH ADVANCES EAST THROUGH THE AREA. THE  
TROUGH WILL PUSH THE POOL OF MOISTURE OVER MUCH OF THE SOUTHEAST  
EASTWARD OVER THE ATLANTIC, AND BETWEEN FRIDAY AFTERNOON TO SATURDAY  
EVENING, PRECIPITABLE WATER VALUES WILL DROP BELOW AN INCH OVER THE  
OHIO VALLEY.  
 
SATURDAY NIGHT INTO SUNDAY, A SHARP UPPER TROUGH DROPS SOUTH, EAST  
OF THE MISSISSIPPI. WITHIN THE TROUGH'S NORTHWEST FLOW, A LOW  
PRESSURE SYSTEM WILL LIKELY FORM. THIS COULD DEVELOP INTO AN MCS AND  
MOVE SOUTH THROUGH WESTERN KENTUCKY.  
 
INTO EARLY NEXT WEEK, THE GLOBAL MODELS AGREE THAT A LOW PRESSURE  
SYSTEM WILL SET UP NEAR WEST VIRGINIA. THIS AREA OF INCREASED  
PRECIPITATION WILL EXPAND AND GIVE THE EASTERN SIDE OF SOUTHERN  
INDIANA AND CENTRAL KENTUCKY LOW CHANCES OF RAIN THROUGH TUESDAY.  
 

 
   
AVIATION
 
(00Z TAF ISSUANCE)  
ISSUED AT 715 PM EDT TUE JUL 7 2020  
 
ISOLATED COVERAGE OF STORMS SO FAR THIS EVENING, BUT FOCUS FOR NEW  
DEVELOPMENT OVER THE NEXT COUPLE OF HOURS COULD BE NEAR HNB/BWG.  
HAVE VICINITY WORDING AT THOSE SITES FOR A COUPLE OF HOURS.  
OTHERWISE VERY LIGHT FLOW WILL KEEP WINDS DOWN THIS PERIOD...ASIDE  
FROM WIDELY SCATTERED AFTERNOON STORMS POSSIBLE AT EACH OF THE  
TERMINALS WEDNESDAY. ONLY OTHER CONCERN IS FOG POTENTIAL. SOME  
GUIDANCE IS GOING FOR FAIRLY LOW VSBY TOWARD DAYBREAK AT EACH OF THE  
SITES, BUT WE HAVE MIXED OUT SOME DRIER AIR THIS AFTERNOON. IN  
DEFERENCE TO SOME OF THOSE MODELS, HAVE PUT IN SOME LOWER VSBY  
AROUND DAYBREAK.  
 

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

 
 

 
 
UPDATE...RJS  
SHORT TERM...13  
LONG TERM...KDW  
AVIATION...RJS  
 
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