537  
FXUS63 KPAH 172228  
AFDPAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PADUCAH KY  
528 PM CDT FRI AUG 17 2018  
   
SHORT TERM
 
(TONIGHT THROUGH SATURDAY NIGHT)  
ISSUED AT 231 PM CDT FRI AUG 17 2018  
 
RADAR COVERAGE UNIMPRESSIVE EARLY THIS AFTERNOON. WATER VAPOR  
SHOWS MID LEVEL TROF AXIS FROM THE GREAT LAKES TO THE OZARKS. THE  
INSTABILITY OVERALL IS LESS THAN IMPRESSIVE, BUT ENOUGH TO SUPPORT  
AN UPTICK IN CONVECTION AS SOME MODEST FORCING DEVELOPS AHEAD OF  
THE APPROACHING TROF, COINCIDENT WITH A SURFACE BOUNDARY JUST OFF  
TO OUR NW THAT WILL MOVE INTO THE AREA LATE TODAY AND THIS EVENING.  
ONCE AGAIN, CONFIDENCE IN COVERAGE IS LOW. ABOUT THE ONLY THING  
THAT SEEMS TO WORK OUT IS, WHERE WE'D LIKE TO SEE MORE RAIN THAT  
WHAT HAS OCCURRED, WE PROBABLY WON'T. SOME OF THE GUIDANCE HINTS  
AT FOG POTENTIAL OVERNIGHT. WE USED A NBM BLEND WITH LAV AND GLAMP  
FOR VSBYS AND SMOOTHED OUT THE CLIMO FAVORED AREAS.  
 
BEST CHANCE POPS WILL BE ACROSS THE SOUTHEAST 1/2 OF THE AREA  
SATURDAY AS THE SURFACE SYSTEM AND TROF ALOFT CONTINUE EAST AND  
SOUTHEAST. SHOULD BE MAINLY DRY SATURDAY NIGHT.  
   
LONG TERM
 
(SUNDAY THROUGH FRIDAY)  
ISSUED AT 231 PM CDT FRI AUG 17 2018  
 
HIGH PRESSURE OVER THE GREAT LAKES SHOULD PROVIDE A RAINFREE END TO  
THE WEEKEND, AS A MID LEVEL TROF OF LOW PRESSURE DIGS SOUTHEAST INTO  
THE CENTRAL PLAINS. WILL BE A BIT UNCOMFORTABLE THOUGH WITH DEW  
POINTS RUNNING UP OVER THE 70 DEGREE MARK IN MANY LOCATIONS.  
 
AFOREMENTIONED H50 TROF WILL THEN HEAD EAST TOWARD THE MID MS RIVER  
VALLEY LATER SUNDAY NIGHT AND MONDAY, BRINGING WITH IT A SURFACE  
FRONT, DECENT OVERALL MOISTURE/DYNAMICS. HENCE, WILL RAMP UP THE  
CHANCES FOR SHOWERS AND SCATTERED THUNDERSTORMS AT THAT TIME. A  
PLUME OF MUCH HIGHER THAN NORMAL PWATS WILL ALSO LIKELY SURGE  
NORTH/EAST ACROSS THE REGION DURING THE DAY MONDAY, AND COULD LEAD  
TO TORRENTIAL DOWNPOURS WITH SOME OF THE ACTIVITY. HOWEVER, THINKING  
NOW IS THAT INCREASED CLOUD COVER/LOWER AFTERNOON TEMPS SHOULD  
PRECLUDE A BIG OVERALL SEVERE STORM RISK. WITH DECENT BULK SHEAR  
EXPECTED, BIGGEST CONCERN WOULD BE WITH A FEW DAMAGING WIND GUSTS IN  
ANY STRONGER ISOLATED STORMS. THE ACTUAL FRONTAL PASSAGE IS EXPECTED  
TO COME LATER MONDAY NIGHT/EARLY IN THE DAY ON TUESDAY, WITH DRYING  
CONDITIONS WORKING EAST INTO THE REGION BY TUESDAY AFTERNOON.  
 
THE BEST NEWS ON THE EXTENDED COMES IN THE LATTER HALF OF THE  
PERIOD, AS WE REPLACE THE ACTIVE WET WEATHER SYSTEM AND ASSOCIATED  
TROF WITH SURFACE HIGH PRESSURE AND COOLER/DRIER NORTHWESTERLIES  
ALOFT. THIS OCCURS IN RESPONSE TO OUR WEDGING BETWEEN THE DEVELOPING  
WESTERN CONUS RIDGE AND THE EASTERN CONUS TROF. THIS  
CONTINUED/PERSISTENT MODEL SIGNAL IS UPPING OUR CONFIDENCE LEVEL IN  
HIGHS FROM NEAR 80 TO THE THE LOWER 80S (WITH LOWER HUMIDITY), AND  
LOWS IN THE LOWER 60S (EVEN SOME UPPER 50S), AS WE MOVE INTO THE  
MIDDLE AND LATTER PORTIONS OF THE WORK WEEK.  
 

 
   
AVIATION
 
 
ISSUED AT 528 PM CDT FRI AUG 17 2018  
 
THE MIDDLE/UPPER LEVEL TROUGH AXIS IS EXPECTED TO PUSH THROUGH THE  
WFO PAH TAF SITES WITHIN THE THE FIRST 12 HOURS OF THE 00Z  
SATURDAY TAF ISSUANCE. THE BROKEN CONVECTION OVER SOUTHEAST  
MISSOURI AND SOUTHWEST ILLINOIS PRIOR TO THIS FORECAST ISSUANCE IS  
EXPECTED TO DIMINISH AS IT GETS CLOSER TO THE KPAH AND KEVV TAF  
LOCATIONS OVERNIGHT, BUT KEPT A VICINITY MENTION IN FOR ALL OF THE  
TAF LOCATIONS. THERE MAY BE SOME SLIGHT VISIBILITY RESTRICTION AS  
THE FRONTAL BOUNDARY STALLS NEAR KCGI BRIEFLY.  
 
FOR THE MOST PART, KEPT VFR CONDITIONS IN PLACE FOR EACH TAF  
LOCATION, WITH THE EXCEPTION BEING WHERE THE ACTUAL FRONTAL  
BOUNDARY SLOWLY PASSES OVER. IN THESE SITUATIONS, INTRODUCED MVFR  
CEILINGS FOR A FEW HOURS.  
 

 
   
PAH WATCHES/WARNINGS/ADVISORIES
 
 
IL...NONE.  
MO...NONE.  
IN...NONE.  
KY...NONE.  

 
 

 
 
AVIATION...SMITH  
 
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