666
FXUS61 KRNK 192003
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
303 PM EST THU DEC 19 2024
SYNOPSIS
LOW PRESSURE OVER THE UPPER MISSISSIPPI VALLEY WILL SWEEP ACROSS THE
OHIO VALLEY ON FRIDAY THEN OFF THE NEW ENGLAND COAST BY SATURDAY
BRINGING SNOW TO THE MOUNTAINS FRIDAY AFTERNOON THROUGH SATURDAY.
COLDER TEMPERATURES WITH HIGH PRESSURE FOLLOW FOR THE WEEKEND.
TEMPERATURES WARM ON MONDAY AND TUESDAY AHEAD OF LOW PRESSURE OVER
THE SOUTHERN PLAINS.
NEAR TERM /THROUGH FRIDAY/
AS OF 120 PM EST THURSDAY...
KEY MESSAGES:
- CLIPPER WILL BRING SNOW TO THE MOUNTAINS STARTING FRIDAY
AFTERNOON
ROBUST SHORT WAVE AND SURFACE LOW PRESSURE SYSTEM OVER THE UPPER
MISSISSIPPI VALLEY WILL REACH THE MID ATLANTIC REGION ON FRIDAY.
CLOUD COVER FILLS IN THIS EVENING AND OVERNIGHT. ISOLATED TO
SCATTERED LIGHT RAIN AND SNOW SHOWERS ARE EXPECTED TO CROSS THE
AREA FRIDAY MORNING WITH LITTLE IMPACT. THE MORE ORGANIZED AREA
OF SNOW WILL REMAIN CONFINED TO THE MOUNTAINS. HRRR AND FV3
MODELS SHOW ABOUT A SIX HOUR PERIOD OF MODERATE SNOW FRIDAY
AFTERNOON AND EVENING BEFORE THE PRECIPITATION BECOMES PRIMARILY
UPSLOPE DRIVEN OVERNIGHT. PROBABILISTIC GUIDANCE MAINTAINS UP
TO 40 PERCENT PROBABILITY OF 2 INCHES OF SNOW BY FRIDAY EVENING,
WITH THE HIGHEST POTENTIAL FROM TAZEWELL COUNTY THROUGH WESTERN
GREENBRIER COUNTY.
THE SURFACE COLD FRONT CROSSES THROUGH THE AREA ON FRIDAY WITH THE
WIND BECOMING NORTHWEST AND THE COLD AIR ADVECTION BECOMING STRONGER
BY FRIDAY AFTERNOON. SIMILAR TO CONDITIONS THURSDAY MORNING,
TEMPERATURES WILL ONLY SEE MINIMAL WARMING ON FRIDAY DUE TO ALL
THE CLOUDS. NOT MUCH DEVIATION FROM GUIDANCE NEEDED FOR LOWS
TONIGHT.
SHORT TERM /FRIDAY NIGHT THROUGH MONDAY/
AS OF 300 PM EST THURSDAY...
KEY POINTS:
1) AREAS WEST OF THE BLUE RIDGE WILL SEE SCATTERED SNOW SHOWERS
FRIDAY NIGHT THROUGH MIDDAY SATURDAY.
2) MUCH COLDER AIR WILL MOVE INTO THE REGION, KEEPING TEMPERATURES
WELL BELOW AVERAGE THROUGH THE PERIOD.
AS THE AXIS OF AN UPPER-LEVEL TROUGH MOVES ACROSS THE AREA FRIDAY
EVENING, SNOW SHOWERS WILL PERSIST THROUGH THE OVERNIGHT ALONG AND
WEST OF THE BLUE RIDGE AS NORTHWESTERLY FLOW WILL CAUSE OROGRAPHIC
LIFTING. EAST OF THE BLUE RIDGE, ISOLATED SHOWERS MAY BRING A TRACE
OF RAIN TO PARTS OF THE PIEDMONT, BUT MOSTLY DRY CONDITIONS WILL
CONTINUE. SNOW ACCUMULATIONS HAVE TRENDED UP SINCE YESTERDAY,
ESPECIALLY FOR THE NC/VA MOUNTAINS, WHERE 1-2" IS EXPECTED WITH THE
HIGHER ELEVATIONS SEEING 2-4". THE SAME CAN BE EXPECTED FOR SUMMERS
AND MERCER COUNTIES IN WV. WESTERN GREENBRIER COUNTY IN WV WILL SEE
THE HIGHEST ACCUMULATIONS, AROUND 3-5" AND POSSIBLY UP TO 6". ALONG
THE BLUE RIDGE, LITTLE ACCUMULATION IS EXPECTED WITH A TRACE TO A
FEW HUNDREDTHS EXPECTED.
THE SNOW SHOWERS CONTINUE THROUGH MIDDAY SATURDAY BEFORE THE TROUGH
MOVES OFF TO THE EAST, WITH DRIER AIR FILLING IN WHICH WILL SHUT OFF
THE SNOW SHOWERS. SATURDAY WILL BE BREEZY, ESPECIALLY ALONG THE BLUE
RIDGE, WITH WIND GUSTS OVER 35 MPH BEFORE REDUCING SATURDAY NIGHT.
SATURDAY NIGHT INTO SUNDAY AND MONDAY WILL BE VERY QUIET, AS A LARGE
HIGH PRESSURE SYSTEM OVER THE NORTHEASTERN US WILL DOMINATE THE
WEATHER PATTERN FOR SEVERAL DAYS, SLIGHTLY WEDGING THE RNK CWA IN
THROUGH TUESDAY.
TEMPERATURES WILL REMAIN WELL BELOW AVERAGE THROUGH THE WEEKEND,
WITH HIGHS IN THE 30S AND 40S, WITH HIGHER ELEVATIONS REMAINING IN
THE UPPER 20S. MONDAY'S HIGHS WILL BE IN THE 30S AREA-WIDE. LOW
TEMPERATURES WILL BE IN THE 20S SATURDAY MORNING BEFORE FALLING INTO
THE TEENS AND 20S SUNDAY AND MONDAY MORNING. A FEW SINGLE DIGIT LOWS
WILL BE POSSIBLE SUNDAY MORNING IN THE HIGHEST ELEVATIONS. WINDS
WILL REMAIN LIGHT DURING THE COLDEST PERIOD, WITH WIND CHILL NOT
BEING A HAZARD.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
AS OF 300 PM EST THURSDAY...
KEY POINTS:
1) TEMPERATURES REBOUND TO NEAR NORMAL FOR THE ENTIRE PERIOD.
2) QUIET WEATHER WILL CONTINUE UNTIL LATE ON CHRISTMAS DAY, WHEN
ANOTHER SYSTEM MOVES INTO THE AREA.
HIGH PRESSURE WILL CONTINUE TO CONTROL THE WEATHER PATTERN FOR
CHRISTMAS EVE AND PART OF CHRISTMAS DAY, WITH DRY WEATHER
PERSISTING. 500MB HEIGHTS WILL CONTINUE TO SLOWLY RISE, WHICH WILL
ALLOW TEMPERATURES TO RETURN TO AROUND NORMAL. EARLY CHRISTMAS
MORNING, A STRAY RAIN SHOWER MAY MOVE INTO THE PIEDMONT AS HIGH
PRESSURE BACKS OUT TO THE NORTHEAST, WITH A WARM SOUTHERLY FLOW
BRINGING MOISTURE BACK INTO OUR AREA. A FEW LOCATIONS MAY INITIALLY
SEE RAIN MIXED WITH SNOW IN THE WV/VA HIGHLANDS, BUT WILL QUICKLY
TURN TO RAIN. MODELS DO NOT AGREE ON WHETHER THIS WILL OCCUR,
THEREFORE CONFIDENCE IS LOW AND POPS ARE ALSO KEPT LOW, AROUND 20%.
AS A LOW DEVELOPS ACROSS THE MISSISSIPPI VALLEY AND MOVES EAST, IT
WILL BEGIN TO WEAKEN AS IT APPROACHES. MOST LOCATIONS WILL RECEIVE
RAINFALL FROM THIS SYSTEM AS IT ARRIVES LATE ON CHRISTMAS DAY
OVERNIGHT INTO THURSDAY. MODELS AGAIN DISAGREE ON THE STRENGTH OF
THE SYSTEM, WITH THE ECMWF HAVING VERY SCATTERED PRECIPITATION
ACROSS THE CWA, WHILE THE GFS HAS MORE WIDESPREAD RAINFALL.
NONETHELESS, RAIN SHOWERS WILL CONTINUE THROUGH THE END OF THE
PERIOD.
TEMPERATURES REBOUND NICELY MIDWEEK, WITH HIGHS IN THE 40S,
RISING FURTHER INTO THE 40S AND 50S LATE WEEK. LOW TEMPERATURES
WILL ALSO SLOWLY RISE MID TO LATE WEEK WITH 20S ON TUESDAY
MORNING RISING INTO THE MID 30S BY THURSDAY MORNING.
EXTENDED AVIATION OUTLOOK...
THE MORE ORGANIZED AREA OF MVFR VISIBILITY SNOW WILL REMAIN
CONFINED TO THE MOUNTAINS, HRRR AND FV3 MODELS SHOW ABOUT A SIX
HOUR PERIOD OF MODERATE SNOW FRIDAY AFTERNOON AND EVENING BEFORE
THE PRECIPITATION BECOMES PRIMARILY UPSLOPE DRIVEN OVERNIGHT.
THIS INCLUDES KBLF. GUSTS IN THE 20 TO 30 KNOT RANGE ARE LIKELY
FRIDAY NIGHT.
SNOW SHOWERS IN THE MOUNTAINS FRIDAY INTO FRIDAY NIGHT COULD
DROP VSBYS TO MVFR TO IFR. THESE SUB- VFR CIGS COULD LINGER INTO
LATE SATURDAY OVER THE MOUNTAINS BEFORE VFR RETURNS FOR SUNDAY
MORNING.
DRY AND WARMER VFR CONDITIONS ARE EXPECTED MONDAY AND TUESDAY.
RNK WATCHES/WARNINGS/ADVISORIES
VA...NONE.
NC...NONE.
WV...NONE.
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...JCB
LONG TERM...JCB
AVIATION...AMS/BMG
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