FXUS61 KRLX 060559
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1259 AM EST SUN DEC 6 2009
.SYNOPSIS...
HIGH PRESSURE MOVES IN TONIGHT AND LINGERS ON SUNDAY.
WEAK FRONT MONDAY AFTERNOON. STRONGER SYSTEM LATE TUESDAY INTO
WEDNESDAY...BRINGING MIXED WINTRY PRECIPITATION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MINOR TWEAKS EARLY THIS EVENING WHEN DROPPING ALL THE LINGERING
ADVISORIES AND WARNINGS. A BIT SLOWER ON THE CLEARING EAST OF THE
INTERSTATE 79 CORRIDOR. AT 00Z...STRONG DEW POINT GRADIENT HAS
WORKED INTO WESTERN WEST VIRGINIA...BUT I HAVE MY DOUBTS IT CAN
SWEEP THROUGH THESE WV HOLLOWS...AS WINDS DIMINISH OVERNIGHT. SO
CAN PICTURE HAZE...FOG...SMOKE AROUND DWELLINGS...THROUGH THE NIGHT
IN THOSE VALLEYS CRW ON E AND S...AND ALSO SOME VALLEYS CKB-EKN.
SURFACE BASE INVERSION BECOMES INVERSION ALOFT DURING THE DAY ON
SUNDAY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE IN CONTROL AT THE START OF THIS PERIOD. ZONAL
FLOW ALOFT...WARM ADVECTION...AND A BIT OF UPPER LEVEL MOISTURE WILL
ALLOW FOR MID/HIGH CLOUDS DURING THE DAY. HELD TEMPERATURES TOWARDS
THE LOW END OF GUIDANCE IN THE EAST...WHERE MUCH OF THE HEATING
ENERGY WILL GO INTO MELTING SNOW. CLOSER TO A CONSENSUS OF MOS IN
THE WEST.
SUNDAY NIGHT/MONDAY WILL FEATURE A SHEARING H500 SHORT WAVE LIFTING
FROM THE CENTRAL PLAINS AT 00Z MONDAY INTO THE SOUTHERN GREAT LAKES
BY 00Z TUESDAY. WEAK FRONTAL BOUNDARY WILL BE PUSHED ACROSS REGION
DURING THE DAY MONDAY. STILL PREFER THE FASTER GFS OVER THE NAM
SCENARIO GIVEN THE ZONAL FLOW. IN ANY CASE...MOISTURE BECOMES QUITE
LIMITED AS THE SHORTWAVE SHEARS...CUTTING OFF THE MOIST SOUTHWEST
INFLOW. LITTLE MIDLEVEL SUPPORT AS WELL...WITH ONLY THE
NORTHERN/WESTERN COUNTIES GETTING GRAZED BY THE ACTUAL SHORTWAVE.
THUS...KEPT POPS IN THE SLIGHT TO VERY LOW CHANCE CATEGORY...WITH
CORRESPONDINGLY LOW QPF. KEPT RAIN/SNOW MIX IN THE GRIDS FOR NOW.
WENT FOR A MORE NARROW DIURNAL RANGE SUNDAY NIGHT/MONDAY THAN
SUGGESTED BY MOS...WARM SIDE BY NIGHT AND COOL SIDE BY DAY...GIVEN
EXPECTED CLOUD COVER.
THERE MAY BE A BRIEF PERIOD OF UPSLOPE SHOWERS MONDAY NIGHT IN THE
MOUNTAINS...AS COLDER AIR BRIEFLY TRIES TO LEAK IN ON NORTHWEST
FLOW. KEPT THESE POPS LOW AS WELL...AND EXPECTING A DRY CWA BY 12Z
TUESDAY...JUST IN TIME FOR RAMP UP TO MORE SIGNIFICANT MIDWEEK
SYSTEM.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
MEDIUM RANGE MODELS ARE SHOWING A SIGNIFICANT LOW PRESSURE SYSTEM
LIFTING UP THROUGH THE OHIO VALLEY MID WEEK...WITH LATEST RUNS
SLOWING ITS ASSOCIATED WARM FRONT AND ONSET OF PRECIP JUST A LITTLE.
THUS...HAVE TRIMMED POPS BACK TUESDAY TO MAINLY ACROSS THE SOUTH
LATER ON THE DAY TUESDAY...THEN RAPIDLY OVERSPREAD THE AREA TUESDAY
EVENING. THE TRACK OF THE LOW ITSELF IS THRU THE WESTERN OHIO
VALLEY...AND INTO MICHIGAN BY LATER IN THE DAY WEDNESDAY. THIS LOW
TRACK...AND STRONG HIGH PRESSURE RIDGING EAST OF THE MOUNTAINS...
WILL INHIBIT THE WARM FRONT FROM LIFTING NORTH THRU THE NORTHERN
MOUNTAINS TUESDAY NIGHT.
THUS...COLD AIR WILL BE TOUGH TO DISLODGE TUESDAY NIGHT AND EARLY
WEDNESDAY IN THE NORTHERN MOUNTAINS. FOR DETAILS...GOING WITH THE
COLDER GFS 850/925 TEMPS WITH THIS SYSTEM TUESDAY NIGHT AND EARLY
WEDNESDAY. THIS SCENARIO WILL KEEP MUCH OF THE PRECIP IN THE
FREEZING/FROZEN FORM TUESDAY NIGHT...ESPECIALLY ON EAST FACING
SLOPES OF THE NORTHERN MOUNTAINS. ELSEWHERE...WARMER AIR WILL RUSH
IN FAST ENOUGH TO GIVE MAINLY RAIN TUESDAY NIGHT AND EARLY WEDNESDAY
AHEAD OF THE WARM FRONT. BY MID MORNING WEDNESDAY...WARMER AIR WILL
FINALLY WIN OUT OVER THE ENTIRE AREA...WITH RAIN TURNING TO RAIN
SHOWERS IN THE WARM SECTOR. PURPOSELY KEPT QPF AMOUNTS LOW ENOUGH TO
PREVENT MENTION OF HEAVY ICE/SNOW IN THE NORTHERN MOUNTAINS AT THIS
EARLY DATE...BUT THE POTENTIAL IS THERE.
THE FOLLOWING COLD FRONT WILL RACE ACROSS THE AREA LATER ON
WEDNESDAY. RAIN SHOWERS ON WEDNESDAY WILL RAPIDLY CHANGE TO SNOW
SHOWERS WEDNESDAY EVENING. THERE WILL LIKELY BE SOME SNOW
ACCUMULATIONS ACROSS MUCH OF THE AREA BY THURSDAY
MORNING...ESPECIALLY MOUNTAINS. HIGH PRESSURE BUILDS IN THURSDAY
WITH SNOW SHOWERS ENDING.
THIS WILL BE A WINDY SYSTEM GIVEN THE STRENGTH OF THE LOW. LOOK FOR
GUSTY SOUTH WINDS DEVELOPING TUESDAY AND TUESDAY NIGHT...ESPECIALLY
MOUNTAIN RIDGETOPS. GUSTY WINDS WILL CONTINUE THRU WEDNESDAY...AND
AFFECT MORE OF THE AREA...AS WINDS TURN MORE WESTERLY WITH THE COLD
FRONT. DID NOT WANT TO PUSH ADVISORY WIND CRITERIA AT THIS EARLY
DATE...BUT THE POTENTIAL IS THERE MAINLY FOR RIDGETOPS.
BEYOND THURSDAY...ANOTHER SYSTEM WILL AFFECT THE AREA FRIDAY AND
SATURDAY...WITH MORE UNSETTLES WEATHER AND BELOW NORMAL TEMPS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MVFR STRATOCU IN THE MTNS WILL BREAK UP AROUND DAWN. WITH
CLEARING...HAZE...SMOKE AND FOG IN THE SHALLOW SURFACE TEMPERATURE
INVERSION MAY LINGER IN VALLEYS FM CKB-CRW ON E INTO THE MOUNTAIN
VALLEYS INCLUDING EKN UNTIL 14Z. SCT CLOUDS AOA 12 THSD FT AND VSBY
UNRESTRICTED AFTER 15Z AS HIGH PRESSURE BRINGS LIGHT FLOW SFC AND
ALOFT.
AFTER 06Z MONDAY...
IFR IN MOSTLY RAIN LATE TUESDAY INTO WEDNESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...CL/MDP/JMV
NEAR TERM...MDP
SHORT TERM...CL
LONG TERM...JMV
AVIATION...TRM
