132  
FXUS63 KLMK 200125  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
925 PM EDT FRI AUG 19 2022  
   
FORECAST UPDATE
 
 
ISSUED AT 925 PM EDT FRI AUG 19 2022  
 
EARLIER CONVECTION OVER SOUTH-CENTRAL KENTUCKY FADED AWAY NICELY  
AROUND SUNSET AS HEATING WAS LOST. PREVIOUS FORECAST OF A QUIET  
OVERNIGHT REMAINS WELL ON TRACK, SO THIS UPDATE WILL BE LIMITED TO  
TWEAKING HOURLY TRENDS FOR THE HI-RES PRODUCTS.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SATURDAY)  
ISSUED AT 325 PM EDT FRI AUG 19 2022  
 
A SHORTWAVE WORKING FROM THE TENNESSEE VALLEY NORTHEAST TOWARDS NEW  
ENGLAND IS CUTTING THROUGH CENTRAL KENTUCKY. THIS IS HELPING TO FIRE  
CONVECTION SOUTH OF THE KENTUCKY PARKWAYS. NOT EXPECTING ANYTHING  
SEVERE, BUT SOME EMBEDDED THUNDER WILL BE POSSIBLE IN THESE ISOLATED  
TO SCATTERED SHOWERS WHICH WILL BEGIN TO FADE WITH THE SETTING SUN.  
 
TONIGHT, A STACKED LOW PRESSURE SYSTEM, WHICH IS EMBEDDED IN A LARGE  
UPPER TROUGH, WILL CONTINUE TO THE SOUTHEAST FROM ITS CURRENT  
LOCATION NEAR THE MINNESOTA/IOWA BORDER, BUT BEFORE ITS INFLUENCE IS  
FELT IN THE LOWER OHIO VALLEY, NEAR SURFACE PRESSURE GRADIENTS WILL  
BE WEAK, KEEPING WINDS LIGHT TO CALM OVERNIGHT. TEMPERATURES WILL  
COOL INTO THE MID 60S IN MOST PLACE WHILE REMAINING SLIGHTLY WARMER  
IN LOUISVILLE.  
 
TOMORROW, THE UPPER LOW WILL BEGIN TO OPEN AS THE COLD FRONT BECOMES  
MORE DISORGANIZED WITH MULTIPLE IMPULSES RADIATING FROM THE SYSTEM.  
AROUND MID-DAY, ONE OF THESE SHORTWAVES WILL TAKE ADVANTAGE OF THE  
MOISTURE AVAILABLE WITH SOUTHERN GULF MOISTURE MEETING WITH MOISTURE  
TRAILING THE LOW PRESSURE SYSTEM OVER THE CWA. EXPECTING PWATS TO  
INCREASE TO AROUND 1.5 INCHES. THE EVENING HOURS WILL LIKELY SEE  
VALUES CLIMB TO NEAR 1.6 TO 1.7 INCHES. SHEAR REMAINS WEAK AND  
MLCAPE VALUES REACH NEAR 1,500 K/KG, BUT MANY SOUNDING PLACE A WARM  
LAYER NEAR 700MB. THIS WILL LIMIT STORM GROWTH, SO ISOLATED TO  
SCATTERED SHOWERS WITH A MIX OF GARDEN VARIETY THUNDERSTORMS ARE  
EXPECTED. THE NAM, AS IT OFTEN DOES, WAS RUNNING BULLISH WITH  
INSTABILITY, BUT THIS WAS DUE TO THE NAM KEEPING THE REGION FAIRLY  
SUNNY TOMORROW. BELIEVE CUMULUS WILL BEGIN BUILDING DURING THE LATE  
AFTERNOON, SO BELIEVE IT'S THE OUTLIER. 5 TO 10 MPH SOUTHERN WINDS  
SHOULD HELP LIFT TEMPERATURES TO THE MID TO UPPER 80S.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 300 PM EDT FRI AUG 19 2022  
 
=====================================  
SYNOPTIC OVERVIEW  
=====================================  
 
CLOSED UPPER LOW OVER MINNESOTA IS FORECAST TO TRANSITION INTO AN  
OPEN WAVE EARLY IN THE PERIOD. THIS FEATURE WILL SLOWLY MOVE  
THROUGH GREAT LAKES THIS WEEKEND AND THEN INTO THE NORTHEASTERN US  
BY NEXT WEEK. OUR REGION WILL BE ON THE SOUTHERN EDGE OF THIS WAVE,  
WITH DEEP MOISTURE POOLING OUT AHEAD OF IT RESULTING IN UNSETTLED  
WEATHER IN THE SUNDAY/MONDAY TIME FRAME. ASSOCIATED SURFACE COLD  
FRONT IS FORECAST TO PUSH THROUGH ON MONDAY WITH DRIER CONDITIONS  
SHOWING UP BY TUESDAY. FOR THE MID-LATE WEEK PERIOD, AN UPPER LEVEL  
TROUGH AXIS IS LIKELY TO REMAIN ANCHORED OVER THE EASTERN US WITH  
THE OHIO VALLEY REMAINING IN A NORTHWESTERLY FLOW ALOFT. MAIN BELT  
OF WESTERLIES WILL REMAIN WELL NORTH OF THE OHIO VALLEY WHILE A  
STALLED OUT COLD FRONT AND POOLING MOISTURE WILL BE FOUND ACROSS  
MUCH OF THE SOUTHEASTERN US.  
 
=====================================  
METEOROLOGICAL DISCUSSION  
=====================================  
 
SATURDAY NIGHT - MONDAY NIGHT:  
 
AFOREMENTIONED CLOSED UPPER LOW OVER MN CURRENTLY IS FORECAST TO  
TRANSITION INTO AN UPPER LEVEL WAVE. THE LATEST 19/12Z SUITE OF  
GUIDANCE CONTINUES TO AGREE WITH THIS WAVE BEING PROGRESSIVE IN  
NATURE, BUT WILL LIKELY BE SLOW TO MOVE THROUGH THE GREAT LAKES THIS  
WEEKEND. AHEAD OF THE SYSTEM, BROAD/DEEP SOUTHWESTERLY FLOW WILL  
ADVECT DEEPER MOISTURE INTO THE REGION. PWATS LOOK TO INCREASE ABOVE  
1.5 INCHES BY SATURDAY NIGHT AND MAY APPROACH 1.75 INCHES BY SUNDAY  
AFTERNOON.  
 
SOUTHERN EDGE OF THE UPPER TROUGH AXIS WILL APPROACH THE REGION ON  
SUNDAY. MODEL CROSS SECTIONS SUGGEST PARTLY/MOSTLY CLOUDY SKIES  
WHICH WILL HAVE AN EFFECT ON INSTABILITY. ENOUGH SUNSHINE SHOULD  
RESULT IN MLCAPE VALUES PUSHING INTO THE 1500-2000 J/KG RANGE BY THE  
AFTERNOON. OVERALL SHEAR PROFILES REMAIN RATHER MARGINAL, BUT  
SHOULD BE ENOUGH TO SUPPORT SOMEWHAT ORGANIZED MULTI-CELLULAR  
CONVECTION. BASED ON THE SHEAR/INSTABILITY PARAMETERS, ISOLATED  
DAMAGING WIND GUSTS WOULD BE THE PRIMARY THREAT. HEAVY RAINFALL IS  
LIKELY AS WELL GIVEN THE HIGH PWATS. HOWEVER, ENVIRONMENTAL  
STEERING FLOW LOOKS TO REMAIN PROGRESSIVE ENOUGH TO KEEP THE  
RESIDENCE TIME OF STORMS IN ANY ONE LOCATION FAIRLY LOW.  
NONETHELESS, SOME ISOLATED HYDRO ISSUES COULD CROP UP, ESPECIALLY IN  
AREAS THAT SEE REPEATED RAINFALL. TEMPERATURES HERE WILL BE  
DIFFICULT TO FORECAST BASED ON CLOUDS/PRECIP. HOWEVER, ENSEMBLE  
GUIDANCE HERE SUGGESTS LOW-MID 80S FOR HIGHS WITH OVERNIGHT LOWS IN  
THE MID-UPPER 60S.  
 
AS THE UPPER TROUGH AXIS SHIFTS EAST ON MONDAY, ASSOCIATED SURFACE  
COLD FRONT WILL SWING THROUGH THE REGION AND BRING AN END TO THE  
SHOWERS/STORMS FROM NW TO SE. HIGHS WILL GENERALLY BE IN THE LOWER  
80S, THOUGH SOME UPPER 70S WILL BE POSSIBLE IN OUR NORTHERN SECTIONS  
OF THE BLUEGRASS REGION. LOWS MONDAY NIGHT SHOULD DROP INTO THE  
UPPER 50S TO THE LOWER 60S.  
 
TUESDAY - FRIDAY:  
 
BEHIND THE FRONT, NORTHWEST FLOW WILL DOMINATE OUR WEATHER PATTERN  
FOR MUCH OF THE REMAINDER OF THE WEEK. OVERALL, THE GUIDANCE  
CONTINUES TO TREND SLIGHTLY DRIER WITH EACH RUN. GIVEN THESE  
TRENDS, HAVE BACKED OFF THE NBM POPS FOR WEDNESDAY. WILL KEEP  
ISOLATED POPS IN FOR THURSDAY, BUT I HAVE A FEELING WE'LL BE ABLE TO  
BACK OFF THOSE AS WELL IN SUBSEQUENT FORECASTS GIVEN THAT FORCING  
ACROSS THE REGION WILL BE VERY WEAK. WE MAY BE ABLE TO GET BACK  
INTO SOME SORT OF DIURNALLY DRIVEN CONVECTION BY FRIDAY AFTERNOON.  
HOWEVER, OVERALL CONFIDENCE IS RATHER LOW.  
 
HIGHS DURING THE PERIOD WILL GENERALLY BE IN THE 83-88 DEGREE RANGE  
FOR HIGHS WITH OVERNIGHT LOWS 63-68 DEGREE RANGE.  
 
=====================================  
WEATHER IMPACTS/RISKS  
=====================================  
 
IN TERMS OF HAZARDOUS WEATHER, SCATTERED TO NUMEROUS THUNDERSTORMS  
ARE EXPECTED ON SUNDAY. THE STRONGEST STORMS WILL BE IN THE  
AFTERNOON/EVENING WITH THE THREAT OF ISOLATED DAMAGING WINDS. IF A  
STRONGER CORE IN A STORM WERE TO DEVELOP, SOME MARGINALLY SEVERE  
HAIL WOULD BE POSSIBLE. ANY STORM WILL BE CAPABLE OF PRODUCING  
LOCALLY HEAVY RAINFALL. HOWEVER, STORM MOTIONS SHOULD BE FAST  
ENOUGH TO LIMIT THE RESIDENCE TIME OVER ANY ONE AREA TO PRECLUDE  
FLOODING. HOWEVER, IN AREAS THAT MAY SEE REPEATED RAINFALL, AN  
ISOLATED RISK OF HYDROLOGICAL ISSUES IS POSSIBLE.  
 
=====================================  
FORECAST CONFIDENCE  
=====================================  
 
OVERALL FORECAST CONFIDENCE FOR THE SATURDAY NIGHT - MONDAY NIGHT  
TIME FRAME IS MEDIUM-HIGH. CONFIDENCE IN THE TUESDAY THROUGH  
FRIDAY PERIOD REMAINS AT THE UPPER END OF THE MEDIUM RANGE.  
 

 
   
AVIATION
 
(00Z TAF ISSUANCE)  
ISSUED AT 715 PM EDT FRI AUG 19 2022  
 
TRANSITIONING BACK INTO MORE OF A SUMMER REGIME TONIGHT, WITH LIGHT  
WINDS AND MAINLY MID-LEVEL CLOUDS EXPECTED ACROSS THE BOARD.  
DEWPOINTS HAVEN'T YET COME UP TO BE CONCERNED ABOUT FOG, SO WE'LL  
STAY VFR. WINDS PICK UP OUT OF THE S-SW LATE SAT MORNING, WITH  
ENOUGH MID-LEVEL CLOUDS FOR A CEILING UNDER CONTINUED WARM  
ADVECTION. COULD SEE A FEW SHOWERS OR T-STORMS BREAK OUT AROUND MID-  
AFTERNOON, BUT CONFIDENCE IS NOT HIGH AND IMPACTS WILL BE BRIEF. FOR  
NOW WILL HANDLE THAT WITH A WINDOW OF PROB30 FOR ALL BUT HNB.  
 

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

 
 

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