588  
FXUS63 KLMK 181039  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
639 AM EDT WED JUL 18 2018  
   
..UPDATED AVIATION DISCUSSION
 
 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 301 AM EDT WED JUL 18 2018  
 
EARLY MORNING IR SATELLITE IMAGERY REVEALS PARTLY CLOUDY SKIES  
ACROSS THE REGION THIS MORNING. ONLY CLOUDS ARE JUST SOME HIGH  
CIRRUS SPILLING SOUTHEASTWARD ACROSS THE AREA. KY MESONET AND NWS  
SHOWING TEMPERATURES IN THE LOWER TO MID 60S OVER THE EASTERN HALF  
OF THE STATE. MAINLY WEST OF I-65, TEMPERATURES WERE IN THE LOWER  
70S. FOR THE REMAINDER OF THE OVERNIGHT, WE EXPECT QUIET WEATHER  
WITH TEMPERATURES DROPPING A FEW MORE DEGREES BEFORE BOTTOMING OUT  
JUST BEFORE SUNRISE.  
 
FOR TODAY AND TONIGHT, A NORTHWEST FLOW ALOFT WILL REMAIN IN PLACE  
AS A SURFACE HIGH SHIFTS FROM THE GREAT LAKES INTO WESTERN NEW  
ENGLAND. THIS FEATURE WILL KEEP SKIES MOSTLY SUNNY WITH A LIGHT  
NORTHEASTERLY FLOW. HIGHS THIS AFTERNOON LOOK TO WARM INTO THE 82  
TO 87 DEGREE RANGE IN MANY AREAS. MOSTLY CLEAR SKIES ARE EXPECTED  
TONIGHT WITH LOWS COOLING BACK INTO THE LOW-MID 60S.  
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 302 AM EDT WED JUL 18 2018  
   
..STRONG TO SEVERE STORMS POSSIBLE FRIDAY
 
 
THURSDAY - THURSDAY NIGHT...  
 
UPPER RIDGING BEGINS TO MOVE OFF TO THE EAST ON THURSDAY, BUT WILL  
STILL HOLD ENOUGH INFLUENCE OVER THE AREA TO KEEP THE FORECAST DRY.  
HIGHS SHOULD BE IN THE MID TO UPPER 80S. BY THURSDAY NIGHT, AN  
ANOMALOUSLY STRONG SHORTWAVE TROUGH WILL MOVE INTO THE UPPER  
MIDWEST. AS DEEPER MOISTURE ARRIVES INTO OUR AREA AHEAD OF THIS  
FEATURE, LOOK FOR INCREASING SHOWER AND STORM CHANCES AFTER MIDNIGHT  
THURSDAY NIGHT.  
 
FRIDAY - FRIDAY NIGHT...  
 
SHORTWAVE TROUGHING WILL REMAIN OVER THE GREAT LAKES AND OHIO RIVER  
VALLEY REGION DURING THIS TIME, WITH THE LEFT EXIT REGION OF A 70  
KNOT UPPER JET NOSING INTO THE LOWER OHIO VALLEY AREA. AT THE SAME  
TIME, LOW LEVEL MOISTURE RETURN WILL BE OCCURRING WITH DEW POINTS  
EXPECTED TO POOL INTO THE LOW 70S. A STRONGLY UNSTABLE AIRMASS  
SHOULD DEVELOP AS THE RICH LOW LEVEL MOISTURE POOLS BENEATH  
STEEPENING LAPSE RATES ALOFT. IN FACT, LATEST SREF GUIDANCE SUGGESTS  
HIGH PROBABILITIES OF GREATER THAN 2000 J/KG OF CAPE, LIKELY HIGHER  
ESPECIALLY WEST OF I-65. GIVEN STRONGER THAN NORMAL DEEP LAYER SHEAR  
VALUES AND THE EXPECTED STRONG INSTABILITY, STRONG TO SEVERE STORMS  
WILL BE POSSIBLE FRIDAY INTO FRIDAY NIGHT. THERE IS SOME QUESTION AS  
TO WHAT ROLE MORNING CONVECTION COULD PLAY ON THE ABILITY TO  
DESTABILIZE IN THE AFTERNOON, NEVERTHELESS MODELS TEND TO AGREE THAT  
MULTIPLE ROUNDS OF STRONG STORMS COULD BE POSSIBLE. AT THIS TIME,  
THE GREATEST THREAT LOOKS TO BE WEST OF I-65 WHERE THE BEST  
INSTABILITY/SHEAR VALUES LINE UP, BUT MANY DETAILS STILL NEED TO BE  
WORKED OUT BEFORE CONFIDENCE CAN GROW IN MORE SPECIFIC  
TIMING/PLACEMENT. SPC DAY 3 OUTLOOK LOOKS GOOD. HIGHS FRIDAY SHOULD  
TOP OUT IN THE 85 TO 90 DEGREE RANGE.  
 
SATURDAY - SUNDAY NIGHT...  
 
SCATTERED TO NUMEROUS SHOWERS AND STORMS SHOULD CONTINUE THROUGH THE  
END OF THE WEEKEND AS AN ANOMALOUS CLOSED LOW SLOWLY WOBBLES THROUGH  
OUR AREA. CONVECTIVE ACTIVITY SHOULD BE MOSTLY DIURNAL IN NATURE,  
BUT WILL STILL HAVE TO KEEP SOME LOW CHANCES IN FOR THE OVERNIGHT  
PERIODS. HIGHS SHOULD BE IN THE LOW TO MID 80S ON SATURDAY, AND ONLY  
AROUND 80 BY SUNDAY. LOWS SHOULD BE IN THE MID TO UPPER 60S EACH  
NIGHT.  
 
MONDAY - TUESDAY...  
 
PRETTY LOW CONFIDENCE TO START THE NEW WORK WEEK AS MODELS DIVERGE  
ON POSSIBLE SOLUTIONS. REGARDLESS, WILL HAVE TO KEEP AT LEAST SOME  
CHANCES FOR SHOWERS AND STORMS IN THE FORECAST AS EITHER THE CLOSED  
UPPER LOW WILL STILL BE IN THE REGION OR REINFORCED TROUGHING WILL  
DRAG ANOTHER FRONT TOWARD THE AREA. A FEW MODEL SOLUTIONS SHOW A DRY  
FORECAST, BUT THE MAJORITY HAVE AT LEAST SOME PRECIPITATION AROUND  
DURING THIS TIME. LOOK FOR HIGHS MOSTLY BACK IN THE MID 80S.  
 

 
   
AVIATION
 
(12Z TAF ISSUANCE)  
ISSUED AT 638 AM EDT WED JUL 18 2018  
 
HIGH PRESSURE CENTERED IN THE GREAT LAKES WILL PROVIDE THE REGION  
WITH VFR CONDITIONS THROUGH THE PERIOD. A LIGHT NORTH TO  
NORTHEASTERLY SURFACE WIND IS EXPECTED. VFR CONDITIONS ARE EXPECTED  
TONIGHT AND AGAIN ON THURSDAY.  
 

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

 
 

 
 
SHORT TERM...MJ  
LONG TERM....BJS  
AVIATION.....MJ  
 
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