509  
FXUS61 KRLX 221956  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
232 PM EST MON DEC 22 2014  
   
SYNOPSIS
 
 
WARM FRONT TONIGHT INTO TUESDAY. LOW PRESSURE MOVES WEST OF THE  
AREA BUT BRINGS RAIN TUESDAY NIGHT INTO WEDNESDAY. COLD FRONT  
WEDNESDAY NIGHT. HIGH PRESSURE LATE CHRISTMAS DAY.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
WITH THE VERY LIGHT PRECIP OVER MAINLY THE NORTHERN MOUNTAINS MOVING  
OUT WITH AN UPPER DISTURBANCE THIS AFTERNOON...AND TEMPERATURES  
GETTING TO JUST ABOVE FREEZING...THE FREEZING RAIN ADVISORY IS  
EXPIRED. THERE WILL BE A LULL IN THE PRECIP FOR THE REMAINDER OF THE  
AFTERNOON WITH EVEN SOME BREAKS IN THE CLOUDS...ESPECIALLY WEST OF  
THE MOUNTAINS WHERE SOUTHEAST DOWNSLOPING WINDS ARE IN EFFECT.  
 
FOR TONIGHT...MODELS SHOW A WARM FRONT LIFTING NORTH THRU THE AREA.  
LATEST NAM/GFS MODELS ARE SOMEWHAT GENEROUS WITH THE POPS AND WITH  
QPF WITH THE WARM FRONT TONIGHT...BUT THE MOST RECENT HI RES  
MODELS ARE DOWNPLAYING THE PROSPECTS FOR PRECIP TONIGHT. THE NEWEST  
HI RES MODELS OF THE HRRR/RAP SEEM TO RECOGNIZE A TYPICAL SHADOW ZONE  
IN THE PRECIP BETWEEN THE OHIO RIVER AND THE MOUNTAINS...AND ALSO EVEN  
DOWNPLAY THE PROSPECTS FOR PRECIP TONIGHT. HAVE BASICALLY CHOSEN A  
COMPROMISE HERE. WHILE DOWNPLAYING THE AGGRESSIVE MODELS...THERE IS  
AN UPPER DISTURBANCE GENERATING SCATTERED LIGHT RAIN OVER THE  
EASTERN TENNESSEE VALLEY THIS AFTERNOON. THIS FEATURE WILL LIFT  
NORTH WITH THE WARM FRONT. SO WE WILL INTRODUCE SOME POPS ALL AREAS  
TONIGHT. WILL HAVE THE GREATER POPS WEST OF THE OHIO RIVER AND IN  
THE MOUNTAINS...WHILE ONLY A SLIGHT CHANCE BETWEEN THE OHIO RIVER  
AND THE MOUNTAINS. IN ANY EVENT...QPF WILL BE LIGHT AND ALL RAIN AS  
TEMPERATURES NOT EXPECTED TO FALL BELOW FREEZING...EVEN IN THE  
NORTHERN MOUNTAINS...WITH INCREASING WARM ADVECTION AND THE CLOUDS.  
LOOK FOR LOWS MAINLY IN THE 30S TO NEAR 40.  
 
FOR TUESDAY...LOOK FOR A BRIEF PRECIP BREAK IN THE WARM SECTOR IN  
THE MORNING BEFORE THE NEXT UPPER DISTURBANCE APPROACHES FROM THE  
WEST WITH SCATTERED SHOWERS WORKING FROM WEST TO EAST MAINLY IN THE  
AFTERNOON. NO THUNDER YET. WITH A BRISK SOUTHERLY BREEZE...LOOK FOR  
TEMPERATURES TO SOAR WELL ABOVE NORMAL...IN THE LOWER 60S IN SOME  
AREAS.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/
 
 
STILL LOOKS LIKE AN INTERESTING SYSTEM WILL IMPACT THE REGION DURING  
THIS PERIOD. BUT IT APPEARS THE CHANCE FOR A WHITE CHRISTMAS IS  
QUITE SMALL ACROSS MOST OF THE AREA. CURRENT THINKING IS THAT EVEN  
THE HIGHEST ELEVATIONS MAY ONLY SEE A FEW TENTHS OF SNOW WEDNESDAY  
NIGHT INTO CHRISTMAS DAY.  
 
NAM/GFS/ECMWF/CANADIAN MODELS ALL INDICATE AN AREA OF LOW PRESSURE  
WILL LIFT NORTH FROM THE GULF COAST INTO THE GREAT LAKES REGION.  
THE GFS AND CANADIAN ARE THE FASTEST MOVING THE LOW NORTHEAST...  
FOLLOWED BY THE ECMWF AND NAM. END RESULT WILL BE A GOOD CHANCE OF  
PRECIPITATION BEGINNING TUESDAY NIGHT.  
 
HAVE GENERALLY GONE CLOSER TO THE GFS/CANADIAN SOLUTION...BRINGING  
AN ASSOCIATED COLD FRONT EASTWARD THROUGH THE AREA ON CHRISTMAS  
EVE. THE RAIN SHOULD MIX WITH...AND/OR CHANGE TO SNOW ACROSS MOST  
LOCATIONS BY 12Z CHRISTMAS DAY.  
 
PRECIPITATION SHOULD DECREASE FROM THE WEST ON CHRISTMAS DAY WITH  
MOST LOCATIONS DRY BY LATE CHRISTMAS.  
 
MODELS INDICATE HIGH TEMPERATURES CHRISTMAS DAY WILL BE IN THE LOW  
40S ACROSS THE LOWLANDS...AND ONLY REMAIN BELOW FREEZING ACROSS THE  
HIGHEST ELEVATIONS. SO ANY REMAINING PRECIPITATION SHOULD CHANGE  
BACK TO RAIN ACROSS MUCH OF THE AREA DURING THE DAY.  
 
HOWEVER...THE REGION WILL EXPERIENCE WINDY CONDITIONS WEDNESDAY  
NIGHT AND CONTINUING THROUGH CHRISTMAS DAY.  
 

 
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
 
CHRISTMAS EVENING WILL CONTINUE TO BE WINDY BEHIND THE FRONT. THE  
SUN WILL LIKELY MAKE A WELCOME RETURN WITH DRY AIR MOVING IN FOR  
FRIDAY.  
 
BY SUNDAY 00Z...MODELS DIVERGE WITH LITTLE AGREEMENT. LEANED MORE  
TOWARDS THE GFS FOR POPS AS THAT SOLUTION APPEARS TO BE MORE  
REALISTIC THAN THE ECMWF. SOME WAVINESS AROUND THE TROUGH MOVING  
EAST WILL CREATE A SLIGHT CHANCE FOR SOME PRECIPITATION. WITH  
WARMER TEMPERATURES...THE MAJORITY OF THIS WILL FALL AS RAIN WITH A  
CHANCE FOR SOME WINTRY MIX AND SNOW OVERNIGHT. A SLIGHT CHANCE OF  
RAIN...AND SNOW AT HIGHER ELEVATIONS...MAY CONTINUE THROUGH MONDAY  
NIGHT.  
 
GENERALLY FOLLOWED HPC GUIDANCE FOR TEMPERATURES WITH A FEW TWEAKS.  
 

 
   
AVIATION /20Z MONDAY THROUGH SATURDAY/
 
 
18Z MONDAY THRU 18Z TUESDAY...  
MVFR CEILINGS WILL HOLD ALONG THE E SLOPES OF THE MOUNTAINS THIS  
AFTERNOON WITH SOUTHEAST UPSLOPE FLOW...AFFECTING BKW. ELSEWHERE  
GENERALLY 4000-6000 CEILINGS WITH BREAKS ESPECIALLY WESTERN SLOPES  
OF THE MOUNTAINS.  
 
AFTER 00Z...WARM FRONT WILL LIFT NORTH THRU THE AREA TONIGHT. MODELS  
ARE VERY GENEROUS WITH RAIN...AS TEMPERATURES WILL STAY ABOVE  
FREEZING. NOT REAL CONFIDENT WITH THE WIDESPREAD RAIN...BUT HAVE  
INTRODUCED AT LEAST LOW POPS TONIGHT. OTHERWISE...LOOK FOR MVFR  
CEILINGS TO HOLD EAST FACING SLOPES OF THE MOUNTAINS...AND VFR  
CEILINGS TO LOWER TO MVFR AFTER 06Z MAINLY WEST OF THE OHIO RIVER  
AND OVER NORTHERN WEST VIRGINIA.  
 
AFTER 12Z TUESDAY...WARM FRONT AND ASSOCIATED LIGHT RAIN SHIFTS  
NORTH OF THE AREA EARLY. GENERALLY BECOMING VFR CEILINGS AREA WIDE  
BY 15Z AS WE GET INTO THE WARM SECTOR...WITH THREAT OF SCATTERED  
SHOWERS WELL AHEAD OF A COLD FRONT INCREASES BY AROUND 18Z.  
 
S TO SE FLOW WILL CONTINUE...WITH HIGHER ELEVATIONS GUSTING 20 TO 25  
KTS AT TIMES THRU THE TAF PERIOD.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...  
 
FORECAST CONFIDENCE: LOW TO MEDIUM.  
 
ALTERNATE SCENARIOS: MVFR CEILINGS AND LIGHT RAIN CHANCES MAY BE  
MORE WIDESPREAD WITH THE WARM FRONT 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 20 21 22 23 00 01 02 03 04 05 06 07  
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02  
CRW CONSISTENCY H H H H H H H H H H H H  
HTS CONSISTENCY H H H H H H H H H H H H  
BKW CONSISTENCY M H H L L M M L L L L L  
EKN CONSISTENCY H H H H H H H H H H H H  
PKB CONSISTENCY H H H H H H H H H H H H  
CKB CONSISTENCY H H H H H H H H H H H H  
 
AFTER 18Z TUESDAY...  
IFR POSSIBLE IN RAIN TUE NT INTO WED...CHANGING TO SNOW SHOWERS  
WED NT...AS AN INTENSE LOW PRESSURE CENTER PASSES.  
 

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

 
 

 
SYNOPSIS...JSH/JMV/LS  
NEAR TERM...JMV  
SHORT TERM...JSH  
LONG TERM...LS  
AVIATION...JMV  
 
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