FXUS61 KRNK 301525
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1025 AM EST MON NOV 30 2009
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHEAST THROUGH THE AREA TODAY AND THEN
OFFSHORE THIS EVENING. HIGH PRESSURE SLIDES IN BEHIND THE FRONT
TONIGHT THROUGH TUESDAY NIGHT BEFORE ANOTHER STRONG LOW PRESSURE
SYSTEM ALONG THE GULF COAST BRINGS MOISTURE BACK NORTH BY
WEDNESDAY. THIS STORM SYSTEM WILL LIFT NORTH ALONG THE
APPALACHIANS WEDNESDAY INTO WEDNESDAY NIGHT FOLLOWED BY MUCH
COLDER AIR BEHIND THE TRAILING COLD FRONT FOR THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT WAS JUST WEST OF THE FORECAST AREA AT 15Z WITH THE
LEADING BAND OF SHOWERS ALREADY INTO THE PIEDMONT. ANOTHER BAND OF
RAIN WAS JUST BEHIND THE FRONT FROM SOUTHWEST PENNSYLVANIA TO
NORTHEAST TENNESSEE THAT WAS ASSOCIATED WITH A SHORT WAVE ROTATING
THROUGH THE NORTHERN TROF. ALL THIS WILL CONTINUE TO MOVE
SOUTHEAST TODAY. STILL EXPECT THE FRONT TO EXIT THE COUNTY WARNING
AREA BEFORE 00Z TONIGHT WITH TEMPERATURES FALLING IN THE MOUNTAINS
THIS AFTERNOON. INCREASED THE PROBABILITY OF RAIN IN THE EAST
WITH THE FIRST BAND OF SHOWERS COMING THROUGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
RATHER STRONG 5H TROF SWEEPS EAST THIS EVENING GIVING THE FRONT A
LITTLE MORE OF A PUNCH TO THE EAST OVERNIGHT. GUIDANCE SHOWS QUITE A
CUTOFF IN MOISTURE AFTER 00Z MOST AREAS...AND EVEN LIMIT MUCH IN THE
NW UPSLOPE REGIONS DESPITE STRONG 85H COLD ADVECTION AND A BRIEF NW
FETCH THIS EVENING. THIS LOOKS IN RESPONSE TO A QUICK SHOT OF
SUBSIDENCE AS THE SURFACE RIDGE BUILDS IN PRETTY FAST OVERNIGHT AND
SHOULD BE JUST TO THE SW LATE. THEREFORE CUT MOST POPS OFF AFTER 00Z
AND ONLY LEFT A BRIEF PERIOD OF UPSLOPE PRECIP DURING THE EARLY
EVENING BEFORE CLEARING THINGS OUT MOST ZONES OVERNIGHT. GUSTY WINDS
ON THE RIDGES ESPCLY NORTH SHOULD KEEP LOW TEMPS UP SOME GIVEN THE
QUICK NATURE TO THE PASSING 85H TROF. HOWEVER STILL LOOKS COLD
ENOUGH ALOFT TO GO AT/BELOW FREEZING WEST OVERNIGHT AND MID 30S EAST
WHERE THE BEST COLD ADVECTION WILL SKIRT BY TO THE NORTH.
WEAK SHORT WAVE WELL BEHIND THE FRONT EARLY TUESDAY MORNING BRINGS A
SFC TROUGH ACROSS THE CENTRAL APPLNS AND TIGHTENS THE PRESSURE
GRADIENT ACROSS THE CWA- MAINLY THE NORTH. THIS INCREASES THE LOW
LEVEL JET AND MODELS ARE NOW INDICATING A 40 TO 50 KNOT JET. SHOULD
HAVE SOME GOOD SUBSIDENCE TUE MORNING AS WELL...SO HAVE RAISED WINDS
TUE MAINLY IN THE MORNING...AND WIND GUSTS AS WELL. LOCATIONS SUCH
AS ROANOKE...NORTHWARD INTO THE ALLEGHANY HIGHLANDS...LOOK TO BE
BREEZY. HAVE ADJUSTED MAX TEMPS TUE TO BE WARMER ACROSS THE SRN
CWA...ESPECIALLY THE PIEDMONT OF NC AND SOUTHSIDE VA AS THE STRONGER
COLD ADVECTION REMAINS NORTH OF THE CWA WITH MORE OF A WEST WIND
BEHIND THE FRONT. TUE NIGHT...WITH A PROGRESSIVE FLOW PATTERN THE
SFC HIGH PRESSURE MOVES EAST OF THE CWA BY WED MORNING. LOW LEVEL
WINDS BACK TO THE SOUTHWEST WE ARE WARM ADVECTING OVERNIGHT. LOOKS
LIKE RIDGES MAY BE QUITE A BIT WARMER THAN VALLEYS...AND PIEDMONT
AREAS WHERE SFC WINDS WILL BE LIGHTER.
WEDNESDAY...THE CUTOFF LOW CURRENTLY OVER NW MEXICO IS PROGGED TO BE
KICKED OUT AND PICKED UP BY THE NEXT WAVE ENTERING THE WESTERN U.S.
ALL MODELS ARE IN AGREEMENT ON THIS...WITH THE MAIN FCST ISSUE THE
TIMING AND EVENTUAL TRACK OF THE ASSOCIATED SFC LOW PRESSURE.
CURRENT MODELS OF CHOICE ARE THE GFS/ECMWF WHICH ARE FASTER THAN THE
NAM. I HAVE RAISED POPS WEDNESDAY...SPEEDING UP THE ARRIVAL OF
PRECIP. WE ALREADY HAD CATEGORICAL POPS WED NIGHT...WHICH STILL
LOOKS GOOD. ANOTHER FCST CONCERN FOR WED IS THE STRONG SOUTHEAST JET
THAT DEVELOPS AHEAD OF THE SFC LOW. THIS WIND DIRECTION TENDS TO
BRING STRONG WIND GUSTS ON THE DOWNSLOPE SIDE OF THE SW TO NE
ORIENTED MTNS IN SW VA...PARTICULARLY TAZEWELL COUNTY...BUT ALSO
SMYTH AND BLAND COUNTIES IN VA...AND MERCER COUNTY WV. I HAVE RAISED
WIND SPEEDS AND GUSTS WED INTO WED EVENING...WITH SOME GUSTS OF 40
TO 45 KNOTS IN THE ABOVE MENTIONED LOCATIONS. FINALLY...HIGH TEMPS
WEDNESDAY HAVE THE POTENTIAL TO BE QUITE WARM...WITH THE STRONG
SOUTHEAST FLOW AND NO LOW LEVEL DAMMING INDICATED. EVEN WITH CLOUD
COVER AND PRECIP MOVING IN IN THE AFTERNOON...TEMPS COULD STILL BE
MILD...SO HAVE RAISED HIGHS MORE INTO THE UPPER 40S TO MID 50S
RANGE.
THURSDAY...DRY SLOT WILL BE MOVING INTO THE SWRN CWA TOWARD
MORNING...SO PRECIP WILL LIKELY END QUICKLY IN THE NE MTNS AND
FOOTHILLS...BUT COULD LINGER WELL INTO THE DAY IN THE NERN CWA. I
ADJUSTED THE POPS TO REFLECT HIGHER CHANCES THU MORNING FOR MOST OF
SW VA AND SE WV.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
SYSTEM WILL BE EXITING THE REGION AND MOVING OVER NEW ENGLAND BY
THURSDAY NIGHT. OVERNIGHT THURSDAY AND INTO FRIDAY
NIGHT...TYPICAL WESTERN UPSLOPE SNOW SHOWERS WILL FALL WITH
FLURRIES AS FAR AS THE BLUE RIDGE. LIGHT ACCUMULATIONS ARE
POSSIBLE ON WESTERN SLOPES...ESPECIALLY ABOVE 3000 FEET DURING THE
OVERNIGHT HOURS THURSDAY AND FRIDAY NIGHT. DURING THE DAY
FRIDAY...TEMPERATURES COULD EDGE ABOVE FREEZING AND SUNSHINE
POKING THROUGH THE CLOUDS FROM TIME TO TIME...COULD MELT/LIMIT
SNOW ACCUMULATIONS. PRIMARILY A WEST WIND WITH NO GREAT LAKE
CONNECTIONS AND DAY TIME MELTING...NOT FORESEEING HIGHLIGHTING IN
HWO AT THIS TIME. EVEN THOUGH SURFACE TEMPERATURES WILL GET ABOVE
FREEZING IN MOST MOUNTAINS LOCATIONS...WARM BOUNDARY WILL BE
SHALLOW AND SNOW SHOWERS/FLURRIES WILL CONTINUE THROUGH THE DAY
FRIDAY. THE WINDS WILL BE BREEZY AND GUSTY IN THE WAKE OF THE
FRONT BUT NOT SEEING ANY CRITERIA BEING MET AT THIS TIME. THESE
WESTERLY WINDS WILL DOWNSLOPE IN THE EAST AND ADD A FEW DEGREES TO
THE TEMPERATURE. HOWEVER...TEMPERATURES WILL BE BELOW NORMAL AND
FEEL CHILLY WITH THE WIND BLOWING.
MOUNTAIN SNOW SHOWERS WILL COME TO AN END FRIDAY NIGHT AS HIGH
PRESSURE BUILDS INTO THE REGION. OVER THE WEEKEND...A WARM FRONT
WILL BRING MODERATING TEMPERATURES TO THE AREA BUT STILL REMAIN
BELOW NORMAL. HIGH PRESSURE WILL REMAIN IN THE REGION THROUGH EARLY
NEXT WEEK.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
BAND OF SHOWERS WILL CONTINUE TO TRACK EAST ACROSS KBLF/KLWB
EARLY THIS MORNING...REACHING KROA AROUND 13-14Z AND THE FAR
EASTERN SITES BY MID/LATE MORNING. THIS SHOULD RESULT IN PERIODS
OF MVFR VSBYS AS WELL AS MVFR CIGS ADVANCING EAST ACROSS ALL SITES
FOR THE MOST PART. HOWEVER LOCATIONS ACROSS THE WEST MAY SEE CIGS
LOWER TO IFR AS THE SHOWERS START TO WEAKEN AND THE FRONT NEARS
THIS MORNING INTO THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL VEER
MORE WESTERLY OVER THE MOUNTAINS THIS MORNING AND THEN TRANSLATE
EAST OF THE BLUE RIDGE THIS AFTERNOON. ONCE THE FRONT
PASSES...NORTHWEST WINDS GUSTING TO 20-25 KNOTS AT TIMES WILL
PREVAIL ESPCLY AROUND KBLF/KROA INTO EARLY THIS EVENING BEFORE
DIMINISHING.
AS COLDER AIR SURGES IN...A BRIEF SNOW SHOWER IS POSSIBLE BEHIND
THE FRONT EARLY THIS EVENING AT KBLF/KLWB...WITH MVFR CIGS RISING
OR SCATTERING OUT TO VFR WITH HIGH PRESSURE BUILDING BACK IN FROM
THE WEST.
ANOTHER STORM SYSTEM WILL BRING A GOOD CHANCE FOR SIGNIFICANT RAIN
BY WEDNESDAY MORNING...WITH A MUCH BETTER CHANCE FOR WIDESPREAD
IFR CONDITIONS...POSSIBLY CONTINUING THROUGH THURSDAY. UPSLOPE
SNOW SHOWERS LOOK TO LINGER MVFR CONDITIONS ACROSS SE WVA INTO
FRIDAY WITH VFR ELSW.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...AMS
SHORT TERM...JH/JJ
LONG TERM...RCS
AVIATION...AMS/JH/WP
