888  
FXUS63 KLMK 142341  
AFDLMK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LOUISVILLE KY  
741 PM EDT TUE AUG 14 2018  
   
..UPDATED AVIATION DISCUSSION
 
 
   
SHORT TERM
 
(THIS EVENING THROUGH WEDNESDAY)  
ISSUED AT 245 PM EDT TUE AUG 14 2018  
 
SHORTWAVE RIDGE OVER THE OHIO VALLEY THIS AFTERNOON WILL START TO  
BREAK DOWN TONIGHT, AS THE UPPER LOW WRAPPED UP OVER EASTERN KANSAS  
STARTS TO OPEN UP AND LIFT OUT. EXPECT A PARTLY CLOUDY EVENING, BUT  
CLOUDS WILL INCREASE THROUGH THE NIGHT AS AN AREA OF ISENTROPIC LIFT  
HEADS OUR WAY. LOW-LEVEL JETTING IS WEAK, BUT WE SHOULD SEE ISOLATED  
TO SCATTERED LIGHT SHOWERS DEVELOPING BEFORE DAYBREAK, GENERALLY  
WEST OF I-65.  
 
A WEAK SURFACE WARM FRONT WILL LIFT THROUGH KENTUCKY IN THE MORNING,  
WITH ONLY MINIMAL CHANGE TO SENSIBLE WX OTHER THAN BUMPING DEWPOINTS  
UP JUST A FEW DEGREES. COVERAGE AND INTENSITY OF PRECIP WILL  
INCREASE IN THE AFTERNOON AS A STRONGER LOW-LEVEL JET TRANSLATES  
ACROSS THE AREA, BRINGING IN AN AIR MASS WITH PRECIPITABLE WATER  
APPROACHING 2 INCHES. ANY SVR THREAT IN THE AFTERNOON WILL BE MORE  
OF A PULSE THREAT, AS MID-LEVEL WINDS DON'T REALLY CRANK UP UNTIL  
AFTER DARK. LOCALLY HEAVY RAIN WILL BE THE BIGGER THREAT, AND WHILE  
WE DON'T EXPECT WIDESPREAD FLOODING, COPIOUS RAINFALL AMOUNTS ARE  
POSSIBLE IF BOUNDARIES CAN INTERACT TO CAUSE TRAINING OF STORMS.  
WILL MENTION ALL THESE FACTORS IN THE HAZARDOUS WEATHER OUTLOOK, BUT  
HOLD OFF ON ANY FLASH FLOOD HEADLINES.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 343 PM EDT TUE AUG 14 2018  
 
...TROPICAL-LIKE SHOWERS AND THUNDERSTORMS TO DOMINATE THROUGH EARLY  
NEXT WEEK...  
 
A CONTINUOUS SERIES OF SHORT WAVES MOVING THROUGH THE CENTRAL INTO  
THE EASTERN U.S. WILL RESULT IN MORE CLOUDS THAN SUN AND A CHANCE OF  
THUNDERSTORMS EACH DAY FOR AT LEAST PART OF THE AREA.  
 
THE FIRST OF THREE SHORT WAVES MOVES NORTHEAST THROUGH THE OHIO  
VALLEY TO START THE EXTENDED. WHILE THE UPPER LEVEL DYNAMICS WITH  
THIS IS NOT ALL THAT IMPRESSIVE, THE STRENGTHENING PRESSURE PATTERN  
AT THE SURFACE AND IN THE LOWEST FIVE THOUSAND FEET OF THE  
ATMOSPHERE WILL USHER IN AMPLE MOISTURE FROM THE GULF OF MEXICO,  
RESULTING IN THE POTENTIAL FOR TORRENTIAL RAINS WITH ANY STORM. THIS  
TROPICAL AIRMASS WILL REMAIN IN PLACE THROUGH EARLY NEXT WEEK.  
 
THERE WILL BE LITTLE RECOVERY BETWEEN THE EXIT OF THE FIRST SHORT  
WAVE LATE THURSDAY NIGHT AND THE ARRIVAL OF THE SECOND BY SATURDAY  
MORNING. DESPITE A BRIEF CUTOFF OF FLOW OFF THE GULF DURING THE  
INTERIM, SURFACE DEW POINTS ARE EXPECTED TO DROP ONLY SLIGHTLY  
BEFORE THE ARRIVAL OF THE SECOND WAVE. THIS WILL SET THE SCENE FOR  
ADDITIONAL THUNDERSTORMS THAT COULD PRODUCE VERY RAINS. HOWEVER,  
LIKE THE FIRST WAVE, THIS SECOND SYSTEM LACKS UPPER LEVEL INTENSITY,  
SO OTHER THAN HEAVY RAINS, WIDESPREAD SEVERE CONVECTION IS NOT  
EXPECTED.  
 
THE NEXT LULL WILL RUN BETWEEN SATURDAY NIGHT AND MONDAY MORNING,  
BUT EVEN SO, SLIGHT PRECIPITATION CHANCES WILL LINGER ALONG THE  
TENNESSEE BORDER, IN LARGE PART DUE TO THE JUICY AIRMASS AND  
LINGERING OVER THE SOUTHERN HALF OF THE REGION. FORECAST MODELS  
START TO DIVERGE ON THE MOVEMENT AND INTENSITY OF THE SYSTEM ENTERING  
THE REGION MONDAY, BUT SUGGEST MORE OF A LONG WAVE THAN THE TWO  
PREVIOUS WEATHER-MAKERS, WITH SLOWER SPEED, AND THE POTENTIAL FOR  
ADDITIONAL STRENGTHENING, MAKING THE CHANCE FOR THUNDERSTORMS TO END  
THE PERIOD CONTINGENT ON TIMING AND PLACEMENT OF THIS. SUFFICE IT  
TO SAY, THOUGH, THAT CLEAR SKIES AND DRY WEATHER WILL NOT BE  
WIDESPREAD BY THE END OF THIS FORECAST PERIOD.  
 
TEMPERATURES WILL VARY LITTLE THROUGH THE EXTENDED. THE ABUNDANCE OF  
CLOUDS WILL DIMINISH THE DIURNAL VARIATION, WITH HIGHS IN THE MID TO  
UPPER 80S AND MOST LOWS WITHIN A FEW DEGREES EITHER SIDE OF 70.  
 

 
   
AVIATION
 
(00Z TAF ISSUANCE)  
ISSUED AT 740 PM EDT TUE AUG 14 2018  
 
VFR CONDITIONS ARE EXPECTED FOR MUCH OF THIS TAF PERIOD. THE MAIN  
TAF CONCERN WILL BE THE ARRIVAL OF SHOWERS AND T-STORMS LATE TONIGHT  
THROUGH TOMORROW. THINK ALL TAF SITES SHOULD SEE MORNING SHOWERS  
WITH PERHAPS A RUMBLE OF THUNDER. BETTER T-STORM CHANCES WILL  
ARRIVE FOR THE AFTERNOON HOURS SO INCLUDED THUNDER MENTION 16Z AND  
AFTER ACROSS THE TAF SITES. WINDS SHOULD BE LIGHT AND WESTERLY OR  
VRB TONIGHT BACKING TO THE SSW FOR TOMORROW.  
 

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

 
 

 
 
SHORT TERM...RAS  
LONG TERM...JBS  
AVIATION...AMS  
 
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