333  
FXUS61 KRLX 021347  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
ISSUED BY NATIONAL WEATHER SERVICE PITTSBURGH PA  
947 AM EDT THU OCT 2 2014  
   
SYNOPSIS
 
 
WARM SUMMER LIKE AFTERNOON TODAY. STRONG COLD FRONT STREAKS ACROSS  
FRIDAY EVENING. MUCH COLDER AIR ARRIVES FOR THE WEEKEND.  
REINFORCING COLD FRONT MAY ARRIVE EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
PUSHED FOG DISSIPATION JUST A BIT FURTHER INTO THE FUTURE GIVEN  
CURRENT TRENDS. EKN...THE GREENBRIER VALLEY...AND THE COALFIELDS  
MAY BE THE LAST TO BREAK UP. OTHERWISE...JUST SPOTTY CU/AC WITH  
HIGH CLOUDS FROM THE OHIO RIVER ON WEST LATER THIS AFTERNOON.  
TEMPERATURES SHOULD RECOVER NICELY ONCE FOG AND INVERSION BREAK.  
GOING NUMBERS LOOK GOOD AND ONLY MADE MINOR TWEAKS.  
 

 
   
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
 
 
FAIRLY COMPLEX FORECAST WITH LOTS OF MOVING PIECES FOR THE SHORT  
TERM. HAVE A STRONG COLD FRONT PUSHING THROUGH...FOLLOWED BY AN  
UPPER AIR TROUGH...RESULTING IN A DRASTIC COOL DOWN BY THE END OF  
THE PERIOD.  
 
HAVE COLD FRONT SET TO CROSS CWA FRIDAY AFTERNOON AND EVENING...  
ENTERING FROM THE WEST AROUND 20Z AND EXITING EAST AROUND 05Z SAT.  
THIS IS FAIRLY CLOSE TO A GFS/ECMWF BLEND...AND A BIT FASTER THAN  
THE NAM. SO HAVE AN AREA OF 80-90 POPS CROSSING THE CWA FROM WEST TO  
EAST FRIDAY AFTERNOON AND EVENING...AND REALLY MAKE ONLY LITTLE  
CHANGES TO TIMING WHEN COMPARED TO PREVIOUS FORECAST. OF NOTE...00Z  
ECMWF AND GFS SPLIT MAX QPF AND TAKE IT NORTH AND SOUTH OF CWA...BUT  
STILL ANTICIPATE ENOUGH SHOWERS AND THUNDERSTORMS MOVING THROUGH TO  
BE COMFORTABLE WITH HIGH POPS...ALTHOUGH QPF FORECAST MAY BE A TOUCH  
HIGH. INSTABILITY REMAINS FAIRLY LIMITED AHEAD OF THE COLD  
FRONT...WITH CAPE UP TO ABOUT 500-800 J/KG. BUT THE CAPE PROFILES  
ARE VERY SKINNY AND WOULD NOT SUPPORT VIGOROUS UPDRAFTS BY  
THEMSELVES WHICH SHOULD LIMIT ORGANIZED...WIDESPREAD STRONG TO  
SEVERE THREAT. WITH THAT SAID...VERY RESPECTABLE BULK SHEAR --  
40-50KTS -- COMBINED WITH GOOD DYNAMICS AND FAST FLOW SHOULD ALLOW  
FOR ATLEAST SOME ENHANCED OUTFLOW WINDS. WILL CONTINUE GUSTY OUTFLOW  
MENTION IN HWO FOR THIS.  
 
WHILE SIDING MOSTLY WITH THE ECMWF AND GFS ON TIMING...DID NOT  
DISCOUNT THE NAM COMPLETELY...AND THINK THE HIGHER RESOLUTION IS  
PICKING UP ON SECONDARY -- POST FRONTAL PRECIP BAND ASSOCIATED WITH  
UPPER LEVEL VORT MAX AND COLD AIR. WITHOUT GOING ALL IN...DID  
INCLUDE A POP MINIMUM JUST BEHIND THE FRONT...WITH ANOTHER AREA OF  
LIKELY POPS QUICKLY MOVING THROUGH DURING THE LATE EVENING AND EARLY  
OVERNIGHT...AS THE COLD AIR ENTERING ALOFT SQUEEZES OUT REMAINING  
UPPER AND MID LEVEL MOISTURE.  
 
UPPER LEVEL TROUGH CROSSES SATURDAY...SO INCREASED CLOUDS  
CONSIDERABLY. DESPITE WHOLE COLUMN DRYING OUT...LOW LEVEL MOISTURE  
REMAINS AND FORECAST SOUNDING SHOW GOOD SATURATED LAYER BELOW  
10KFT...LINGERING ACROSS WV LOWLANDS FOR MUCH OF THE DAY. COULD EVEN  
GET DRIZZLE OR A LIGHT SHOWER OUT OF THIS BUT DID NOT INCLUDE LOW  
END POPS AT THIS POINT.  
 
DID NOT CHANGE HIGHS AND LOWS ALL THAT MUCH...ALTHOUGH DID COOL THE  
MOUNTAINS SATURDAY AND WENT WITH A NON-DIURNAL AT THE HIGHEST  
ELEVATIONS AS COLD 850 AIR FILTERS IN. THIS HAPPENS JUST AS THE LAST  
OF THE LOW LEVEL MOISTURE IS BEING SQUEEZED OUT...AND INCLUDED SOME  
SNOW FLAKES ABOVE 4000 FEET LATE SATURDAY. HAVE TEMPS DIPPING INTO  
THE UPPER 20S SATURDAY NIGHT IN THE NORTHERN MOUNTAINS...SO WILL  
INCLUDE POTENTIAL FREEZE IN HWO. HELD OFF ON MENTION OF FROST WHERE  
TEMPS ARE IN THE LOW TO MID 30S...EXPECTING WINDS TO KEEP UP ENOUGH  
TO LIMIT ANY DECOUPLING AND FROST FORMATION. WILL NEED TO BE  
RE-EVALUATED AS WE GET CLOSER.  
 

 
   
LONG TERM /SATURDAY THROUGH WEDNESDAY/
 
 
BAROCLINIC ZONE SHIFTS SLOWLY NWD THIS PERIOD AS THE SWD EXTENT OF  
THE L/W SLOWLY RETREATS. THIS RESULTS IN GRADUALLY MODERATING  
TEMPERATURES. MODELS DISAGREE ON TIMING AND EXTENT OF REINFORCING  
COLD FRONT EARLY NEXT WEEK. FOLLOWED WPC IDEA OF CHANCE POPS MON  
INTO TUE...WITH NO APPRECIABLE COOL DOWN THEREAFTER. BLENDED IN WPC  
TEMPERATURES FOR MOST OF THE FCST.  
 

 
   
AVIATION /14Z THURSDAY THROUGH MONDAY/
 
 
LAST EARLY MORNING FOR WIDESPREAD VALLEY FOG...BURNING OFF 12Z TO  
13Z.  
 
VFR WITH JUST A FEW TO SCATTERED CU AT 4 TO 6 THSD FT AGL THIS  
AFTERNOON WITH THIN HIGH CIRRUS ABOVE. SOME PATCHES OF MID DECK AOA  
10 THSD FT MAY ARRIVE 00Z TO 06Z FRIDAY IN THE WESTERN LOWLANDS.  
 
LOW LEVEL FLOW FROM THE SE-S INCREASING 06Z TO 12Z FRIDAY.  
 
ONLY FOG FIGURED FOR 06Z TO 12Z FRIDAY IS IN THE DEEP MOUNTAIN  
VALLEYS NEAR ELKINS.  
 
CLOUDS AT 5 TO 10 THSD FT THICKENING FROM SW 06Z TO 12Z FOR THE OHIO  
RIVER VALLEY COUNTIES. LEADING LIGHT SHOWERS MAY BE NEARING NE KY  
AND SE OHIO BY 12Z FRIDAY.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...  
 
FORECAST CONFIDENCE: MEDIUM.  
 
ALTERNATE SCENARIOS: LEFTOVER STRATUS OVER RIVERS MAY LINGER A HOUR  
OR SO LONGER THAN 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.  
 
AFTER 12Z FRIDAY...  
BRIEF IFR IN FAST MOVING SHOWERS AND/OR THUNDERSTORMS FRIDAY  
AFTERNOON INTO FRIDAY NIGHT. POST FRONTAL IFR OVERNIGHT FRIDAY  
NIGHT...LINGERING IN MOUNTAINS EARLY SATURDAY...IN RAIN AND LOW  
CLOUDS IN THE COLD AIR ADVECTION  
 

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

 
 

 
SYNOPSIS...KTB/MZ  
NEAR TERM...CL  
SHORT TERM...MZ  
LONG TERM...TRM  
AVIATION...KTB  
 
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