FXUS61 KRLX 221756
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1237 PM EST TUE DEC 22 2009

.SYNOPSIS...
HIGH PRESSURE GIVING WAY TO LOW PRESSURE SYSTEM CHRISTMAS.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
WEAK ISENTROPIC LIFT THIS AFTERNOON GIVING SOME FLURRIES. LIFT DIES 
THIS EVENING. UNTIL LOW GETS CLOSER LATER IN THE WEEK THE LOW LEVEL 
MOISTURE WILL STILL BE AROUND SO SOME CLOUDS WILL CONTINUE.  PLAYED 
MIN TEMPS TONIGHT A BIT HIGHER THEN MOS WITH LOW LEVEL MOISTURE 
AROUND.  ALSO WENT A BIT BELOW MAX WED WITH SNOW STILL IN PLACE.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ALL MODELS HAVE NEXT STRONG LOW PRESSURE SYSTEM AFFECTING OUR AREA 
LATE THURSDAY INTO CHRISTMAS DAY FRIDAY. MODEL TIMING DIFFERENCES IN 
THE SPEED OF THE SYSTEM HAVE BEEN GREATLY RESOLVED...WITH THE 
GENERAL TREND TO GO WITH A SLOWER SOLUTION. THE TRACK OF THIS SYSTEM 
WILL BE WELL TO THE WEST...UNLIKE THE LAST SYSTEM...AND WILL LIFT 
NORTH NORTHEAST FROM THE SOUTHERN PLAINS THURSDAY INTO THE UPPER 
MISSISSIPPI VALLEY ON CHRISTMAS DAY. THIS WILL PUSH A WARM FRONT 
NORTHWARD ACROSS OUR REGION THURSDAY NIGHT...FOLLOWED BY A COLD 
FRONT FROM THE WEST CHRISTMAS DAY.

THIS SCENARIO WILL PUT MOST OF OUR AREA ON THE MILD SIDE WITH RAIN. 
HOWEVER...WITH THE TRACK BEING THIS FAR WEST...AND STRONG COLD HIGH 
PRESSURE RIDGING SOUTHWARD EAST OF THE MOUNTAINS TO PROVIDE COLD AIR 
DAMMING...THE PRECIPITATION MAY BEGIN AS A WINTRY MIX IN THE 
NORTHERN AND CENTRAL WEST VIRGINIA MOUNTAINS THURSDAY NIGHT 
     ESPECIALLY EAST FACING SLOPES. THIS MAY CONTINUE INTO FRIDAY 
MORNING...BEFORE THE MILDER AIR FINALLY WORKS IN. THUS...THERE IS A 
POTENTIAL FOR SIGNIFICANT ICING...WHICH WILL BE MENTIONED IN 
HAZARDOUS WEATHER OUTLOOK AND IMPACT PRODUCTS. IN ADDITION...850 MB 
SOUTHERLY LOW LEVEL JET WITH THIS RAIN BAND MAY PROVIDE GUSTY WINDS 
ON MOUNTAIN RIDGETOPS THURSDAY NIGHT. 

RAINFALL AMOUNTS WITH THIS SYSTEM LOOK TO BE TRENDING DOWN... 
GENERALLY AROUND HALF AN INCH NOW. GIVEN THIS DOWNTREND OF 
AMOUNTS...WILL HOLD OFF ON ANY MENTION OF WATER PROBLEMS FROM THE 
HEAVY SNOW PACK AT THIS TIME. FOR NOW THE BIGGER ISSUE IS ICING 
POTENTIAL IN THE NORTHERN AND CENTRAL MOUNTAINS.

COLD FRONT SWEEPS THRU ON FRIDAY...WITH RAIN CHANGING TO POST 
FRONTAL RAIN SHOWERS...THEN TO SNOW SHOWERS FRIDAY NIGHT AS COLDER 
AIR WRAPS AROUND THE DEPARTING LOW PRESSURE SYSTEM.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
FRIDAY NIGHT IS BEGINNING TO LOOK LIKE A MESSY NIGHT AS LATEST 
MODELS DO NOT BRING IN THE COLD AIR ALOFT UNTIL AFTER 00Z IN THE 
WEST AND 06Z IN THE EAST.  WITH THIS IN MIND...APPEARS PRECIPITATION 
IN THE MOUNTAINS COULD BE A WINTRY MIX OF RAIN...TO FREEZING 
RAIN/SLEET TO SNOW WITH THE PRECIPITATION.  ACROSS THE LOWLANDS... 
THE PRECIPITATION SHOULD GENERALLY CHANGING TO A MIX OF RAIN/SNOW 
AND THEN ALL SNOW. HAVE GONE WITH A NON-DIURNAL TEMP CURVE AS TEMPS 
SHOULD NOT FALL ACROSS THE HIGHER ELEVATIONS UNTIL LATER.

THE REGION SHOULD THEN REMAIN UNDER THE INFLUENCE OF AN UPPER LEVEL 
LOW...WITH CONTINUED CHANCES OF SNOW SHOWERS THRU THE WEEKEND.
SURFACE HIGH PRESSURE THEN BUILD IN LATE IN THE PERIOD...SHUTTING
OFF ANY PRECIP CHANCES.

GENERALLY USED HPC TEMP GUIDANCE...WITH SOME TWEAKS TO REFLECT 
LATEST ENSEMBLE GUIDANCE.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THERE WILL BE ENOUGH LOW LEVEL MOISTURE STILL AROUND TO KEEP CLOUDS 
THROUGH THE PERIOD.  CIGS WILL BE VFR SOUTH TO MVFR ACROSS CENTRAL 
WEST VIRGINIA AND NORTH. VSBYS WILL LOWER TO MVFR LEVELS WITH A BIT 
OF FOG AROUND TONIGHT.  SOME IFR VSBYS WILL BE ENCOUNTERED IN RIVER 
VALLEYS 06Z TO 14Z. 

AFTER 18Z WEDNESDAY...
SYSTEM IMPACTS AREA THURSDAY NIGHT INTO FRIDAY...WITH RAIN AND 
POSSIBLE IFR. FREEZING RAIN ALSO A THREAT IN THE WV MOUNTAINS.

&&

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

&&

$$
SYNOPSIS...AAR
NEAR TERM...MDP
SHORT TERM...JMV
LONG TERM...JSH
AVIATION...AAR