628
FXUS61 KRNK 161953
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
353 PM EDT WED OCT 16 2013
.SYNOPSIS...
A COLD FRONT APPROACHES FROM THE WEST TONIGHT AND STALLS IN THE
MOUNTAINS OVERNIGHT. A DISTURBANCE WILL RIDE NORTHEAST ALONG THIS
FRONT THROUGH MUCH OF SOUTHWEST VIRGINIA ON THURSDAY. WEAK HIGH
PRESSURE RETURNS FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 340 PM EDT WEDNESDAY...
SATELLITE LOOP SHOWED THAT LOW CLOUDS FINALLY MIXED OUT OF SOUTHSIDE
AS SOUTHERLY SFC FLOW REDEVELOPED THIS AFTERNOON AS MID AND HIGH
CLOUDS SPREAD EASTWARD INTO REGION AHEAD OF COLD FRONT TO OUR WEST
IN THE OHIO VALLEY. WSR-88D SHOWED LIGHT RETURNS SHOWERS AND
SPRINKLES ENTERING WESTERN PORTIONS OF CWA THIS AFTERNOON FIGHTING
DRIER AIR ACROSS OUR AREA.
THIS EVENING INTO TONIGHT...MOISTURE CONTINUES TO INCREASE AS COLD
FRONT EDGES EAST TOWARDS THE WESTERN MOUNTAINS. FELT A BLEND OF THE
RNK WRFARW AND GFS CAPTURED THE POPS BEST WITH HIGHEST CHANCES IN
THE WEST. WITH PLENTY OF CLOUDS LEANED LOW OVERNIGHT TOWARDS THE
WARMER MET GUIDANCE WITH READINGS FROM THE UPPER 40S ACROSS THE
HIGHER ELEVATIONS OF GREENBRIER COUNTY IN WEST VIRGINIA TO THE UPPER
50S IN THE SOUTHEAST.
A COLD FRONT WITH A WAVE OF LOW PRESSURE ALONG IT SLOWLY MOVES EAST
ACROSS OUR AREA ON THURSDAY. WIDESPREAD LIGHT TO MODERATE RAIN
EXPECTED FOR MUCH OF THE REGION THURSDAY. HOWEVER...MOST OF THE RAIN
SHOULD BE GONE BY DARK THURSDAY EVENING. LEANED THURSDAY POPS
TOWARDS THE FAST GFS OVER THE SLOWER NAM. PLAYED THE HIGHEST POPS IN
THE NORTHEAST AND TAPER OFF HEADING EASTWARD. WENT WITH HIGH
THURSDAY CLOSER TO ADJMABBC WITH READINGS FROM THE AROUND 60 IN
THE WEST TO THE LOWER 70S IN THE EAST.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 350 PM EDT WEDNESDAY...
FRONT EXPECTED TO QUICKLY CLEAR THE AREA THURS EVENING...AND AS
SHORT WAVE LIFTS NORTHEAST ACROSS NEW ENGLAND. PREFER THE FASTER GFS
VS. NAM IN THESE SITUATIONS...AND ITS CERTAINLY POSSIBLE THAT ALL
PRECIP WILL BE EAST OF FCST AREA BY 6PM...EXCEPT FOR SOME LINGERING
UPSLOPE SHOWERS IN FAR NORTHWEST BEHIND THE FRONT. KEEPING A LOW CHC
POP ACROSS FAR EAST IN CASE SLOWER SOLUTION DOES PAN OUT...BUT BY
JUST AFTER MIDNIGHT HAVE REMOVED ALL POPS FROM EAST. SOME GUSTY
WINDS ALONG RIDGE TOPS AND INCREASED THOSE AS LITTLE FOR OVERNIGHT
BEHIND FRONT BUT GRADIENT RELAXES QUICKLY WITH WEAK HIGH PRESSURE
BUILDING IN BY FRIDAY...AND ONLY ISSUE THERE SHOULD BE TEMPERATURES
GIVEN THE POTENTIAL FOR HIGH CLOUDS DEVELOPING AT SOME POINT AS MAIN
TROUGH TO THE WEST STARTS TO DIG AGAIN AND MID LEVEL FLOW INCREASES
FROM SW. AT THIS POINT...AM LEANING TOWARD MORE SUN THAN CLOUDS WITH
SLOWER ARRIVAL OF CLOUDS...AND GIVEN THAT GUIDANCE IS UP A NOTCH
FROM PREV RUNS...BUMPED HIGHS UP A COUPLE DEGREES ACCORDINGLY.
SATURDAY LIKELY TO BE THE CLOUDIER DAY AS MAIN TROUGH DIGS AND
ANOTHER WEAK FRONT APPROACHES FROM WEST. AT THIS POINT THIS FRONT
LOOKS MAINLY DRY...BUT THERE ARE SOME OUTLIER SOLUTIONS WHICH NOT
ONLY SQUEEZE OUT A FEW SHOWERS IN FAR WEST AS FRONT ARRIVES...BUT
ALSO GENERATE SOME WEAK ISENTROPIC LIFT FARTHER EAST. GFS HAS A HINT
OF THIS...AND BRAND NEW 12Z ECMWF EVEN A LITTLE MORE AGGRESIVE WITH
THIS IDEA. HAVE MAINTAINED SLIGHT CHC POPS FAR WEST AND FAR EAST BY
LATER PART OF SATURDAY...AND WILL CONTINUE WATCHING THESE TRENDS
CLOSELY...BUT FOR NOW STILL MAINLY DRY...BUT SEASONABLY COOL WITH
LITTLE SUNSHINE...MAY HAVE NEEDED TO GO EVEN CLOUDIER THAN I DID.
ANY PRECIP THAT DOES OCCUR IN FAR WEST OR FAR EAST WOULD BE VERY
LIGHT.
SUNDAY COOL HIGH PRESSURE BUILDS IN AGAIN WITH BRIEFLY MORE ZONAL
FLOW AS NEXT ENFORCEMENT IN THE LARGE SCALE TROUGH BEGINS TO DROP
DOWN OUT OF CENTRAL CANADA. SHOULD BE DRY DAY BUT BELOW NORMAL TEMPS
DESPITE DECENT AMOUNT OF SUNSHINE.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT TUESDAY...
MODELS ARE CONVERGING ON A SOLUTION THAT SHOULD YIELD A COOL BUT
NOT NECESSARILY A CLOUD FREE WEEKEND. BROAD COLD UPPER LEVEL
TROUGH WHICH HAS BEEN FOCUSED PRIMARILY OVER THE ROCKIES AND
NORTHERN PLAINS IS FORECAST TO MOVE EAST WITH POLAR WESTERLIES
INCREASING ACROSS THE GREAT LAKES AND OHIO VALLEY. POLAR FRONT AND
BAROCLINIC ZONE IS FORECAST TO HANG OUT CLOSER TO THE
COAST...EXTENDING FROM THE COASTAL CAROLINAS SOUTHWEST ACROSS THE
GULF COAST STATES. MOST OF THE PRECIPITATION THIS WEEKEND SHOULD
BE FOCUSED ALONG THIS BAROCLINIC ZONE...BUT MODELS HAVE YET TO
COMPLETELY ELIMINATE THE POSSIBILITY OF MOISTURE SNEAKING INTO THE
MID ATLANTIC. FOR SUNDAY...THE WESTERLIES SHOULD EVENTUALLY SCOUR
THE AREA OF DEEPER MOISTURE. OUR FORECAST AREA THEN BECOMING
DEPENDENT ON SHORT WAVE ENERGY ROUNDING THE UPPER LEVEL TROUGH
FROM THE GREAT LAKES TO PROVIDE ANY CLOUD ELEMENTS OR
PRECIPITATION CHANCES. ATTM...WILL ENTERTAIN DRY CONDITIONS FOR
THE FIRST HALF OF NEXT WEEK...FORECAST NWRLY WIND FLOW ALOFT BEING
CLIMATOLOGICALLY DRY.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 115 PM EDT WEDNESDAY...
SCT TO BKN MVFR CU/SC WITH BKN/OVC AC/CS ABOVE THE LOWER LAYER.
SATELLITE LOOP SHOWED THE BREAK IN THE CLOUD COVER IN THE
FOOTHILLS FILLING IN QUICKLY THIS AFTERNOON. LOW CLOUDS ALONG
COASTAL PLAIN TRYING TO PUSH WESTWARD THIS AFTERNOON.
LIGHT SFC FLOW WILL TURN MORE SOUTH TO SOUTHWEST IN THE 4-8 KT
RANGE. MEDIUM TO HIGH CONFIDENCE IN WINDS THIS AFTERNOON INTO
TONIGHT. MEDIUM CONFIDENCE IN CEILING AND VISIBLE THIS AFTERNON
INTO TONIGHT.
COLD FRONT TO THE WEST WILL BRING SOME LOWER CIGS AT BLF/LWB AT
TIMES THIS EVENING INTO TONIGHT WITH SHOWERS. HINDER ING FACTOR
FOR RAIN IS THE DRIER AIR IN PLACE ACROSS OUR REGION.
THIS FRONT WILL STALL/SLOW DOWN ACROSS THE MOUNTAINS TONIGHT. WAVE
OF LOW PRESSURE MOVING ALONG IT FROM THE SOUTHWEST TO SEND BETTER
THREAT OF RAIN INTO THURSDAY...ALONG WITH LOWER CIGS/VSBYS AT MOST
IF NOT ALL TERMINALS WITH HIGHER CONFIDENCE OF SUB VFR IN THE MTNS
INCLUDING ROANOKE. ONCE THIS WAVE PASSES THE FRONT CONTINUES EAST
AND HIGH PRESSURE BUILDS IN FRIDAY. COULD SEE LINGERING SUB VFR
CIGS IN THE AREA SHORTLY BEHIND THE FRONT...ESPECIALLY SE WV WITH
SOME UPSLOPE FLOW. AS WE HEAD INTO LATER FRIDAY INTO THE WEEKEND
APPEARS WILL SEE VFR WITH HIGH PRESSURE IN PLACE BUT SW FLOW ALOFT
MAY SEND MID/HIGH DECK INTO OUR REGION.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK/KM/WP
NEAR TERM...KK
SHORT TERM...SK
LONG TERM...SK
AVIATION...KK/WP