587  
FXUS63 KPAH 290415  
AFDPAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PADUCAH KY  
1115 PM CDT TUE MAR 28 2017  
   
UPDATE
 
 
ISSUED AT 1100 PM CDT TUE MAR 28 2017  
 
UPDATED FOR 06Z AVIATION ONLY.  
 

 
   
SHORT TERM
 
(TONIGHT THROUGH THURSDAY NIGHT)  
ISSUED AT 121 PM CDT TUE MAR 28 2017  
 
MORE ATMOSPHERIC EVOLUTION/TRANSFORMATION WILL BE OCCURRING DURING  
THE NEXT 24-36 HOURS OF THE FORECAST, AS WE PRIME UP FOR ANOTHER  
SYSTEM TAKING SHAPE IN THE DESERT SOUTHWEST...AND POISED ON A  
TRACK THAT IS NOT TOO DISSIMILAR FROM THE LAST SYSTEM. IN FACT,  
THE DESTABILIZATION AND RE-MOISTENING OF THE LOWER TROP LOOKS TO  
BE ON SIMILAR TRACK AS WELL, AND THE WIND FIELDS ALOFT TOO LOOK  
SIMILAR. THIS MEANS A SLIGHT RISK FOR SVR THUNDERSTORMS AS THE  
SYSTEM TRACKS IN, BEGINNING LATE WED NIGHT AND EXTENDING THRU  
THURS PM/EVENING, THE LATTER TIME PORTION OF WHICH COULD BE MOST  
SIMILAR TO YESTERDAY'S SYSTEM IN THE SPATIAL AND INTENSITY FIELDS.  
AT THIS WRITING, HOWEVER, THE ENHANCED RISK IS A TAD FURTHER TO  
OUR SOUTH.  
 
ADJUSTED HIGHS/LOWS TO COLLABORATE WITH SLIGHTLY WARMER READINGS  
WITH OUR EASTERN NEIGHBORS (LMK), AND SLIGHTLY COOLER WEST  
(SGF/LSX), ON A COUPLE TIME PERIODS.  
   
LONG TERM
 
(FRIDAY THROUGH TUESDAY)  
ISSUED AT 121 PM CDT TUE MAR 28 2017  
 
WITH THE LATEST DETERMINISTIC RUNS OF THE 12Z TUESDAY GFS AND THE  
00Z TUESDAY (12Z COMING IN AT THIS TIME) ECMWF, BOTH GUIDANCE MODELS  
TAKE THE CURRENT CLOSED LOW SOUTH OF THE FOUR CORNER'S REGION IN THE  
DESERT SOUTHWEST U.S. THE SYSTEM BECOMES MORE VERTICALLY STACKED  
SLOWING IT'S PROGRESS TOWARD AND THROUGH THE WFO PAH FORECAST AREA  
THROUGH DAYBREAK FRIDAY.  
 
THE TIMING, LOCATION, AND INTENSITY OF THESE SYSTEMS A QUITE SIMILAR  
THROUGH 18Z THURSDAY, IN LINE WITH THE TUESDAY WPC'S EXTENDED  
FORECAST DISCUSSION.  
 
GIVEN THE EXPECTED VERTICALLY STACKED NATURE OF THIS SYSTEM AND TO A  
LESSER DEGREE THE INFLUENCE OF TRANSIENT SYSTEMS TO THE NORTH AND  
SOUTH OF THE CLOSED LOW IN THE EXTENDED FORECAST PERIOD, AM INCLINED  
TO GO WITH THE SLOWER GFS EASTWARD MOVEMENT OF THE SYSTEMS. THIS  
WOULD BE CLOSER TO THE CLASSIC SYSTEM WAVE MOVEMENT OF 15 KNOTS  
FORWARD MOVEMENT. AT THE SAME TIME, PREFER TO BLEND THE MORE  
NORTHERLY ECMWF CLOSED LOW TRACK WITH THE MORE SOUTHERN GFS  
GUIDANCE, ALLOWING FOR A MORE SOUTHERLY OCCLUDED SURFACE PATTERN.  
 
FROM A SENSIBLE WEATHER BASIS, THIS WILL LIKELY YIELD TO LINGERING  
RAIN SHIELD IN WEST KENTUCKY AND SOUTHWEST INDIANA EARLY FRIDAY  
MORNING. RIDGING SHOULD THEN DOMINATE THROUGH AT LEAST SUNDAY  
EVENING ACROSS THE WFO PAH FORECAST AREA BEHIND THE LOW AND KEEP  
THINGS RELATIVELY DRY THROUGH THE WEEKEND.  
 
WITH THE TRAIN OF WEATHER SYSTEMS MOVING ACROSS THE SOUTHERN PLAINS  
AND LOWER MISSISSIPPI VALLEY RECENTLY, ANTECEDENT MOISTURE SHOULD  
PROVIDE A RICH RESERVOIR OF BUOYANCY FOR SURFACE BASED AIR PARCELS.  
THIS AMBIENT MOISTURE SOURCE MAY INTEGRATE INTO A MORE SOUTHERLY  
BAROCLINIC ZONE, SHIFTING THE LEADING CONVECTIVE SHIELD FURTHER  
SOUTH THAN WHAT THE 00Z ECMWF IS ADVERTISING FOR NEXT MONDAY  
MORNING. THIS WOULD PLACE THE WFO PAH FORECAST AREA IN THE  
DEFORMATION ZONE IN NEXT WEEK'S SYSTEM, REDUCING THE SEVERE  
POTENTIAL SOMEWHAT, BUT INCREASING PRECIPITATION EFFICIENCY (HEAVY  
RAIN?) OVER PARTS OF THE AREA.  
 
WITH THE SLIGHTLY MORE SOUTHERLY TRACK, PLAN TO LEAD TOWARD THE  
COLDER BIAS REGIONALLY BLENDED MODEL GUIDANCE FOR TEMPERATURES,  
DEWPOINTS, AND WIND FIELDS.  
 
FOR NEXT MONDAY AND TUESDAY, ANTICIPATE MAIN CONVECTIVE ACTIVITY  
WILL BE FOCUSED IN THE AFTERNOON AND EVENING HOURS. BETTER CHANCES  
OF THUNDERSTORM ACTIVITY SHOULD REMAIN WITHIN THOSE TIME FRAMES NEXT  
WEEK.  
 

 
   
AVIATION
 
 
ISSUED AT 1047 PM CDT TUE MAR 28 2017  
 
SATELLITE SHOWING CLEARING OF LOW CLOUDS FROM SOUTH TO NORTH  
ACROSS THE AREA. SO HAVE IMPROVED FCST TO VFR WITH ONLY MID CLOUDS  
FOR THE OVERNIGHT AND SOME PATCHY FOG WHERE THE LIGHT WINDS MAY  
DIE OFF. BRING IN CUMULUS DECK WEDNESDAY AFTER SUNRISE AND BRING  
WINDS AROUND TO EASTERLY.  
 

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

 
 

 
 
AVIATION...KH  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab KY Page
The Nexlab IL Page
The Nexlab IN Page
The Nexlab MO Page Main Text Page