FXUS61 KRNK 302319
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
619 PM EST MON NOV 30 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE OFFSHORE THIS EVENING. ANOTHER STRONG LOW
PRESSURE SYSTEM ALONG THE GULF COAST LIFTS NORTH ALONG THE
APPALACHIANS WEDNESDAY INTO WEDNESDAY NIGHT...DELIVERING MUCH COLDER AIR
FOR THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
BACK EDGE OF RAIN SHOWERS IS NOW OVER SOUTHSIDE VA INTO THE NW
PIEDMONT OF NC...AND WILL BE EXITING SHORTLY. COLD NW WINDS WILL
KEEP THE UPSLOPE CLOUDINESS IN OVER THE FAR WEST INTO THE EVENING
ISOLATED TO SCT LIGHT SNOW SHOWERS...BUT NOTHING ACCUMULATING.
MADE SOME TIMING CHANGES TO THE POPS...SPEEDING THE ENDING OF THE
PRECIP UP.
WINDS WILL BE GUSTY OUT OF THE NORTHWEST BEHIND THE
FRONT...ESPECIALLY IN THE NORTHERN COUNTY WARNING AREA AROUND 12Z
ON TUESDAY. MOST OF THE GUIDANCE KEPT THE 850 WINDS AOB 40 KNOTS
SO WILL HOLD OFF ON ANY ADVISORY FOR NOW.
850 MB TEMPERATURES AROUND -4 TO -6 DROP INTO THE WESTERN COUNTY
WARNING AREA OVERNIGHT BUT BY 12Z TUESDAY COLDER AIRMASS IS
ALREADY PULLING NORTHEAST OUT OF THE AREA. NOT MUCH SPREAD IN THE
GUIDANCE FOR LOWS TONIGHT. STAYED ON THE COOL SIDE OF MAV/MET
NUMBERS IN MOST LOCATIONS. WITH LOTS OF SUNSHINE ON TUESDAY HIGH
TEMPERATURES WILL BE BACK AROUND NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
RAIN WILL BREAK OUT ON WEDNESDAY ACROSS THE CWA AS A STRONG AREA
OF LOW PRESSURE MOVES JUST WEST OF THE APPLN MTNS. THE OP
GFS/GEFS/ECMWF WERE FOLLOWED AS OPPOSED TO THE NAM...ALTHOUGH THE
18Z NAM HAS A MORE REASONABLE TRACK. H85 WINDS FROM THE GFS GET TO
75KTS JUST WEST OF A BLF/JFZ LINE WED PM...AND SOME TYPE OF WIND
HEADLINE WILL LIKELY BE NEEDED AS THE EVENT NEARS ACROSS THE WEST.
WITH A MOIST AND A NEARLY STABLE SOUNDING IN THE LLVLS...MIGHT BE
DIFFICULT TO GET HIGH WIND CRITERIA...ALTHOUGH SOME TREES MAY
TOPPLE WITH HVY RAIN. WILL HOLD OFF ANY HEADLINES FOR NOW
CONSIDERING MUCH OF THIS EVENT WILL OCCUR IN THE FOURTH PERIOD.
CONCERNED ABOUT CONVECTION ACROSS THE SE LIMITING QPF THIS FAR
NORTH...BUT WITH NEARLY EVERY MODEL ON BOARD...DID INC QPF FOR
THIS EVENT...BUT NOT QUITE AS HIGH AS HPC FOR THE TIME BEING. COLD
AIR AND DOWNSLOPING WIND BUILD IN QUICKLY INTO THURS MORNING...AND
REDUCED POPS QUICKER THAN PREVIOUS FORECAST...REMOVING THE HIGH
POPS EAST OF THE BLUE RIDGE THROUGH WED AFTERNOON. NOT THE BEST
UPSLOPE COMPONENT FOR SE WEST VA AND SW VA ON THURSDAY...BUT SOME
LIGHT ACCUMS ARE POSSIBLE THURSDAY ABV 3K FEET.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ON FRIDAY...AN UPPER LEVEL LOW WILL BE IN THE VICINITY OF THE GREAT
LAKES WITH THE FLOW OVER THE SOUTHERN APPALACHIANS BEING
WEST-NORTHWEST. THIS PATTERN WILL NOT CHANGE MUCH THROUGH FRIDAY
NIGHT. THEREFORE...CONTINUED BROKEN STRATOCUMULUS CLOUDS WITH OFF
AND ON AGAIN LIGHT MOUNTAIN SNOW SHOWERS/FLURRIES. ANY ACCUMULATION
WILL BE CONFIDED TO EXTREME WESTERN SLOPES OF SOUTHEASTERN WEST
VIRGINIA. EAST OF THE BLUE RIDGE...WILL SEE MOSTLY SUNNY SKIES
BROUGHT TO YOU BY DOWNSLOPING WESTERLY WINDS. SNOW SHOWERS WILL END
AND SKIES WILL CLEAR ACROSS THE AREA THROUGH EARLY NEXT WEEK. WITH
HIGH PRESSURE OVER THE AREA AND ZONAL FLOW ALOFT...NO PRECIPITATION
IS EXPECTED UNTIL THE MIDDLE OF NEXT WEEK.
DID NOT CHANGE MUCH IN THE EXTENDED FORECAST WITH THE EXCEPTION OF
RAISING POPS FRIDAY ALONG WESTERN SLOPES AND EXTENDING THEM DEEPER
INTO FRIDAY NIGHT.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND WITH THE
TROUGH REMAINING TO THE WEST FRIDAY NIGHT FOLLOWED BY A CHILLY
SURFACE HIGH OVER THE WEEKEND. TEMPERATURES ARE EXPECTED TO REBOUND
EARLY NEXT WEEK WITH A PASSING OF A WARM FRONT.
THE 12Z GFS SHOWING A WAVE ROUNDING THE TROUGH IN THE SOUTHERN
PLAINS...GRABBING SOME GULF MOISTURE...THEN PRODUCING SNOW IN OUR
NECK OF THE WOODS FRIDAY NIGHT AND SATURDAY. THE 12Z GFS WAS THE
ONLY MODEL SHOWING THIS LIGHT SNOW EVENT. SURFACE FLOW REMAINS OUT
OF THE WEST-NORTHWEST...LOW LEVEL FLOW IS WESTERLY AND UPPER LEVEL
FLOW IS SOUTHWESTERLY. THE COLD FRONTAL BOUNDARY FROM WEDNESDAY
NIGHT RAIN EVENT WILL BE ALONG THE SOUTHERN TIP OF FLORIDA. GIVEN
THIS PATTERN...A MID LEVEL WAVE COULD RIDE OVER THE AREA BUT
MOISTURE SHOULD ONLY CREATE OVERCAST SKIES TO POSSIBLE FLURRIES. THE
GFS IS PRODUCING A TENTH TO A QUARTER INCH OF LIQUID PRECIP...WHICH
IS WAY OVER DONE. LIKING THE ECMWF WITH SHORT WAVES ROUNDING THE
TROUGH...BUT KEEPING BULK OF PRECIPITATION OVER FLORIDA.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
RAIN SHOWERS EXITING THE TAF LOCATIONS OF LYH/DAN ATTM...AND
EXPECTING VFR CONDITIONS AT THE ROA/LYH/DAN SITES THROUGH THE
PERIOD WITH NW WINDS NOSING DOWNWARD LATE THIS EVENING AND BY
DAYBREAK AT ROANOKE.
FURTHER WEST...NW FLOW UPSLOPE CLOUDINESS WILL KEEP MVFR CIGS AT
BLF THROUGH THE FIRST FEW HOURS OF THE TAF THIS EVENING...BUT
LOOKING AT MOISTURE EXITING THE AREA B4 MIDNIGHT. LOOK FOR VFR
CONDITIONS AFT 03Z AT BLF...WITH VFR AT LWB THROUGH THE PERIOD.
ANOTHER STORM SYSTEM WILL BRING A GOOD CHANCE FOR SIGNIFICANT
RAIN BY WEDNESDAY AFTERNOON...WITH WIDESPREAD IFR
CONDITIONS...POSSIBLY CONTINUING THROUGH THURSDAY. UPSLOPE SNOW
SHOWERS LOOK TO LINGER MVFR CONDITIONS ACROSS SE WVA INTO FRIDAY
WITH VFR ELSEWHERE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/KM
NEAR TERM...AMS/WP
SHORT TERM...KM
LONG TERM...RCS
AVIATION...AMS/JH/WP
