967  
FXUS61 KRLX 201839  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
239 PM EDT SUN AUG 20 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE SUNDAY THROUGH TUESDAY. STRONG COLD FRONT LATE  
TUESDAY/TUESDAY NIGHT. COOLER AND DRIER FOR THE END OF THE  
WEEK.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
AS OF 120 PM SUNDAY...  
 
WEAK HIGH PRESSURE KEEPS THE CWA DRY AND WARM TODAY. A MINOR  
IMPULSE AT 500 MB PASSES TO OUR NORTH OVERNIGHT THOUGH TRENDED  
TOWARDS SREF AND GFS ENSEMBLES KEEPING THE FORECAST DRY. THERE  
SHOULD BE FOG AGAIN IN THE RIVER VALLEYS OVERNIGHT THOUGH THE  
IMPULSE AND A FULL DAY OF SUN TODAY MAY LESSEN THE DENSITY AND  
EXTENT OVERNIGHT. DESPITE THIS, STILL KEPT A GENERAL MENTION OF  
FOG IN THE RIVER VALLEYS.  
 
MONDAY HIGH PRESSURE HOLDS ON ALBEIT WEAKLY, BUT SHOULD BE  
ENOUGH TO KEEP US DRY AGAIN WITH MINIMAL CLOUD COVER EXCEPT IN  
THE MOUNTAINS WHERE DAYTIME HEATING MAY BE ENOUGH TO SPARK A FEW  
ISOLATED SHOWERS.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
AS OF 230 PM SUNDAY...  
 
5H TROUGH DIGS SOUTHEAST INTO THE GREAT LAKES WITH AN  
ACCOMPANYING FRONT AT THE SURFACE. THIS FEATURE WILL DRIVE A  
COLDER AIRMASS OF CONTINENTAL CANADIAN AIR INTO THE EASTERN US  
BY WEDNESDAY NIGHT. HAVE FRONT PEGGED TO BE ALONG THE OHIO RIVER  
ALONG THE WV-OH BORDER AT AROUND 06Z WEDNESDAY AND THIS FEATURE  
WILL DRIVE SHOWER AND ISOLATED THUNDERSTORM ACTIVITY ACROSS THE  
FORECAST AREA WITH DECENT WETTING RAINS. MADE SOME ADJUSTMENTS  
TO THE MODEL BLEND POPS BY JUST A FEW HOURS BUT GENERALLY  
ACCEPTING GUIDANCE.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
AS OF 230 PM SUNDAY...  
 
COOL PERIOD IN THE LONG TERM AS CANADIAN AIRMASS IN CONTROL OF  
OUR SENSIBLE WEATHER. SURFACE HIGH DOMINATES THE EASTERN  
SEABOARD. USED GUIDANCE THROUGHOUT THE PERIOD.  
 

 
   
AVIATION /19Z SUNDAY THROUGH FRIDAY/
 
 
12Z SUNDAY THRU 12Z MONDAY...  
AS OF 130 PM SUNDAY...  
 
WEAK HIGH PRESSURE FOR VFR UNTIL MORE RIVER VALLEY FOG AFTER  
10Z BEFORE A RETURN TO VFR AGAIN.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...  
 
FORECAST CONFIDENCE: HIGH, EXCEPT LOW TO MEDIUM WITH FOG.  
 
ALTERNATE SCENARIOS: TIMING, DENSITY, AND LOCATION OF RIVER  
VALLEY FOG TONIGHT COULD VARY. MID LEVEL IMPULSE MAY MIX UP  
BL MOISTURE FIELD A BIT FOR A DIFFERENT FOG PATTERN TONIGHT.  
 
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY  
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:  
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.  
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.  
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.  
 
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05  
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01  
CRW CONSISTENCY H H H H H H H H H H H L  
HTS CONSISTENCY H H H H H H H H H H H L  
BKW CONSISTENCY H H H H H H H H H H H M  
EKN CONSISTENCY H H H H H H H H H H H L  
PKB CONSISTENCY H H H H H H H H H H H L  
CKB CONSISTENCY H H H H H H H H H H H M  
 
AFTER 18Z MONDAY...  
DENSE RIVER VALLEY FOG POSSIBLE EACH MORNING.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...NONE.  
OH...NONE.  
KY...NONE.  
VA...NONE.  
 

 
 

 
SYNOPSIS...JW/26  
NEAR TERM...JW  
SHORT TERM...KMC  
LONG TERM...KMC  
AVIATION...JW  
 
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