765  
FXUS61 KRLX 170821  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
421 AM EDT TUE OCT 17 2017  
   
SYNOPSIS
 
 
DRY HIGH PRESSURE WITH COOL MORNINGS AND WARM AFTERNOONS, WITH  
TEMPERATURES MODERATING THROUGH THE WEEKEND. A COLD FRONT  
CROSSES ON MONDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 250 AM TUESDAY...  
 
NO SIGNIFICANT CHANGES NECESSARY TO THE PREVIOUS FORECAST. HIGH  
PRESSURE IN CONTROL WITH DRY CONDITIONS. DEW POINTS HAVE NOT  
FALLEN AS MUCH AS PREVIOUSLY FORECAST, SO NOT AS WIDESPREAD OF A  
FROST/FREEZE AS EXPECTED, WITH DENSE VALLEY RIVER FOG STARTING  
TO DEVELOP, AS EVIDENT ON SATELLITE AND AIRPORT OBSERVATIONS.  
 
ONCE FOG BURNS OFF, EXPECTING A MOSTLY SUNNY DAY, A FEW DEGREES  
WARMER THAN MONDAY. ANOTHER COOL NIGHT ON TAP TONIGHT, WITH  
DENSE RIVER VALLEY FOG, AND PATCHY FROST EXPECTED. WILL ALLOW  
THE DAY SHIFT TO REEVALUATE WHETHER ANY ADDITIONAL FROST  
HEADLINES WILL BE NECESSARY FOR TUESDAY NIGHT/WEDNESDAY MORNING.  
 

 
   
SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/
 
 
AS OF 420 AM TUESDAY...  
 
A WEAK UPPER LEVEL SHORT WAVE TROUGH CROSSES WEDNESDAY NIGHT.  
HOWEVER, WITH VERY DRY AIR IN PLACE, AND SURFACE HIGH PRESSURE  
IN CONTROL, REINFORCED BY ANOTHER ON THURSDAY, THE DRY WEATHER  
CONTINUES. AN UPPER LEVEL RIDGE CROSSES FRIDAY, AS SURFACE HIGH  
PRESSURE DRIFTS SLOWLY EAST OF THE AREA.  
 
CENTRAL GUIDANCE TEMPERATURES REFLECT A SLOWING OF THE WARMING  
TREND, ON ACCOUNT OF THE SHORT WAVE TROUGH AND REINFORCING HIGH.  
VALLEY FROST IS AGAIN POSSIBLE THURSDAY MORNING, BUT  
TEMPERATURES DOWN TO OR BELOW FREEZING IN THE NORTHERN MOUNTAIN  
VALLEYS WILL BE ISOLATED AT BEST. MINIMUM RH VALUES WILL DIP  
INTO THE 20S IN PARTS OF THE AREA WEDNESDAY AFTERNOON, WITH 30S  
AGAIN WIDESPREAD THURSDAY AFTERNOON, BECOMING MORE CONFINED TO  
THE MOUNTAINS FOR FRIDAY AFTERNOON.  
 

 
   
LONG TERM /SATURDAY THROUGH MONDAY/
 
 
AS OF 420 AM TUESDAY...  
 
UPPER LEVEL AND SURFACE RIDGING MOVE OFF THE EAST COAST THIS  
WEEKEND, ALLOWING AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT  
TO APPROACH FROM THE WEST SUNDAY NIGHT. MODELS WERE CONVERGING  
ON A MONDAY PASSAGE OF THE COLD FRONT, ALONG WITH FULL LATITUDE  
AMPLIFICATION OF THE UPPER LEVEL TROUGH. THE FRONT SPELLS A HIGH  
CHANCE FOR SHOWERS, AND PERHAPS THUNDER, ON MONDAY. AFTER  
DRYING OUT BEHIND THE FRONT MONDAY NIGHT, THE SLOWING, DEEPENING  
UPPER LEVEL TROUGH OVER THE AREA SPELLS LOTS OF CLOUDS, AND THE  
CHANCE FOR SHOWERS, ON TUESDAY.  
 
CENTRAL GUIDANCE REFLECTS A WARM WEEKEND ON TAP, FOLLOWED HY  
TEMPERATURES FALLING BACK TO NORMAL EARLY NEXT WEEK.  
 

 
   
AVIATION /08Z TUESDAY THROUGH SATURDAY/
 
 
AS OF 120 AM TUESDAY...  
 
LOCAL LIFR/VLIFR VALLEY FOG POSSIBLE 06-13Z IN SHELTERED RIVER  
VALLEYS. OTHERWISE, VFR WITH LIGHT SURFACE WINDS.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...  
 
FORECAST CONFIDENCE: MEDIUM.  
 
ALTERNATE SCENARIOS: FOG MAY BE MORE WIDESPREAD THAN CURRENTLY  
FORECAST.  
 
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.  
 
DATE TUE 10/17/17  
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19  
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15  
CRW CONSISTENCY H M M M M H H H H M M M  
HTS CONSISTENCY H M M M M H H H H M M M  
BKW CONSISTENCY H H H H H H H H H M M M  
EKN CONSISTENCY L L L L L M M M H M M M  
PKB CONSISTENCY H H M M M H H H H M M M  
CKB CONSISTENCY M M M M M H H H H M M M  
 
AFTER 06Z WEDNESDAY...  
DENSE VALLEY FOG POSSIBLE EACH MORNING THIS WEEK.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...FREEZE WARNING UNTIL 10 AM EDT THIS MORNING FOR WVZ031-032-039-  
040-519>526.  
FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR WVZ005>011-  
013>020-024>030-033-034-515>518.  
OH...FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR OHZ066-067-075-  
076-083>087.  
KY...FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR KYZ101>103-105.  
VA...FROST ADVISORY UNTIL 10 AM EDT THIS MORNING FOR VAZ003-004.  
 

 
 

 
SYNOPSIS...TRM/SL  
NEAR TERM...SL  
SHORT TERM...TRM  
LONG TERM...TRM  
AVIATION...SL  
 
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