462
FXUS61 KRNK 162020
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
320 PM EST THU JAN 16 2025
SYNOPSIS
LOW PRESSURE CROSSING THE OHIO VALLEY WILL BRING SNOW MAINLY
TO SOUTHEAST WEST VIRGINIA, AND GUSTY WINDS TO THE MOUNTAINS
THIS EVENING INTO TONIGHT. HIGH PRESSURE WILL EXPAND TO COVER
THE MID-ATLANTIC AND CAROLINAS FRIDAY. A LARGE STORM SYSTEM
WILL BRING WIDESPREAD PRECIPITATION FRIDAY NIGHT INTO SATURDAY
IN ADVANCE OF AN ARCTIC AIRMASS THAT WILL ARRIVE ON SUNDAY.
NEAR TERM /THROUGH FRIDAY/
AS OF 400 PM EST THURSDAY...
KEY MESSAGES:
1) WINTER STORM WARNING REMAINS IN EFFECT FOR WESTERN
GREENBRIER TODAY AND TONIGHT
2) WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR MERCER AND
SUMMER COUNTIES
3) A WIND ADVISORY IS IN EFFECT FOR MUCH OF THE BLUE RIDGE THIS
EVENING INTO TONIGHT
SATELLITE IMAGERY INDICATES SUNSHINE FOR MUCH OF THE LOWER MID-
ATLANTIC, WITH SOUTHWESTERLY WINDS IN PLACE AHEAD OF AN
APPROACHING UPPER LEVEL DISTURBANCE. THE DISTURBANCE WILL MOVE
ACROSS THE MOUNTAINS THIS EVENING SHORTLY AFTER SUNSET,
RESULTING IN UPSLOPE SNOW SHOWERS AFFECTING MAINLY PORTIONS OF
SOUTHEAST WEST VIRGINIA INTO THE ALLEGHANY HIGHLANDS AND THE NEW
RIVER VALLEY. STILL RUNNING WITH A WINTER STORM WARNING FOR
WESTERN GREENBRIER COUNTY, WHERE 4 TO 6 INCHES OF SNOW IS
FORECAST, WITH LOCALLY HIGHER AMOUNTS. UP TO 3 INCHES REMAIN IN
THE FORECAST FOR MERCER AND SUMMERS COUNTIES, WHERE A WINTER
WEATHER ADVISORY REMAINS IN PLACE.
THE DISTURBANCE WILL ALSO BRING A BRIEF PERIOD OF STRONG WINDS
ACROSS THE CENTRAL APPALACHIANS, BRINGING 45 TO 50 MPH GUSTS
ACROSS THE HIGHER RIDGES FROM WATAUGA COUNTY THROUGH THE
SOUTHERN SHENANDOAH VALLEY. THE WINDOW FOR THESE WINDS ARE
SHORT HOWEVER AS THE DISTURBANCE MOVES QUICKLY AWAY TO THE EAST
OVERNIGHT, AND HAVE THEREFORE ISSUED A WIND ADVISORY IN EFFECT
FROM 7 PM THIS EVENING THROUGH 4 AM FRIDAY.
ONCE THE DISTURBANCE BEGINS TO EXIT TO THE EAST OVERNIGHT, HIGH
PRESSURE WILL QUICKLY FILL IN FROM THE WEST. THIS WILL RESULT
IN DECREASING WIND SPEEDS, IN ADDITION TO DIMINISHING MOUNTAIN
SNOW SHOWER ACTIVITY AND DECREASING CLOUDS AS DAWN APPROACHES.
UPPER LEVEL RIDGING PASSING ACROSS THE REGION ON FRIDAY,
COMBINED WITH SUNSHINE AND WINDS SHIFTING FROM THE SOUTH WILL
MAKE FOR NEAR-NORMAL AFTERNOON TEMPERATURES. HIGHS WILL RANGE
FROM THE MID 30S ALONG THE INTERSTATE 64 CORRIDOR WEST OF
LEXINGTON, TO THE MID/UPPER 40S ACROSS THE PIEDMONT.
KEEPING AN EYE ON AN APPROACHING DISTURBANCE
SHORT WAVE CROSSING THROUGH THE LONG WAVE EASTERN UNITED STATES
TROUGH WILL MOVE THROUGH THE MID ATLANTIC AREA TODAY AND TONIGHT.
THE BEST SYNOPTIC SCALE LIFT WITH THE UPPER JET AND POSITIVE
VORTICITY ADVECTION, FOLLOWED BY UPSLOPE LIFT WILL BE IN THE 10AM-
10PM TIME FRAME. ENOUGH LIQUID EQUIVALENT PRECIPITATION, AROUND 0.5
INCHES AND LARGE ENOUGH SNOW RATIOS, ROUGHLY 15:1 TO GET SNOW
ACCUMULATIONS IN SOUTHEAST WEST VIRGINIA OF 2 TO 8 INCHES. SOME
LOCALLY HIGHER AMOUNTS ARE POSSIBLE IN WESTERN GREENBRIER COUNTY.
ALSO MODELS ARE SUGGESTING SOME RELATIVE INSTABILITY THIS AFTERNOON
THAT MAY BE ENOUGH FOR SNOW SQUALLS OR AT LEAST NARROW BANDS OF
HEAVIER SNOWFALL RATES. COLDER AIR ALOFT DOES ARRIVE IN THE AREA
AROUND THAT TIME. BIGGEST QUESTION IS THE AMOUNT OF MOISTURE. THE
AIR MASS IS STARTING THE DAY WELL BELOW 0.25 INCHES OF PRECIPITABLE
WATER AND SOME OF THE EARLY SNOWFALL MAY GO INTO SATURATING THE AIR
MASS INSTEAD OF ACCUMULATING. BUT, EVENTUALLY THE PRECIPITABLE WATER
VALUES ARE BACK UP AROUND 0.25 INCHES. LATEST HRRR HAS THE SNOW
REACHING MOST OF SOUTHEAST WEST VIRGINIA BETWEEN 7AM AND 10AM.
THIS FEATURE GOES BY WITH THE 500MB TROUGH AXIS TO THE EAST BY
FRIDAY MORNING. WINDS TURN TO THE WEST AND NORTHWEST TONIGHT. THE
LOW LEVEL JET INCREASES THIS EVENING WITH THE STRONGEST 850MB WIND
FROM 00Z/7PM TO 06Z/1AM WITH GOOD PRESSURE RISES, 5-8MB IN 6 HOURS
AT THE SAME TIME. WILL ASSESS AGAIN TODAY TO DETERMINE IF A WIND
ADVISORY IS NEEDED ALONG THE SOUTHERN BLUE RIDGE. WIND SPEEDS DROP
OFF QUICKLY BY FRIDAY MORNING. BY THEN SURFACE HIGH PRESSURE
DIRECTLY OVER THE CENTRAL AND SOUTHERN APPALACHIANS.
UPPER RIDGING ON FRIDAY AND MORE SUNSHINE WILL RESULT IN
TEMPERATURES AROUND NORMAL. STAYED CLOSE TO A NBM/LAV GUIDANCE BLEND
FOR HIGHS AND LOWS THROUGH THIS PERIOD.
SHORT TERM /FRIDAY NIGHT THROUGH MONDAY NIGHT/
AS OF 220 PM EST THURSDAY...
KEY MESSAGES:
1) WINTRY MIX OF SNOW, SLEET, AND FREEZING RAIN EXPECTED
SATURDAY MORNING BECOMING MOSTLY RAIN BY AFTERNOON.
2) WINDY, BECOMING BITTERLY COLD, WITH MOUNTAIN SNOW SHOWERS
MONDAY INTO TUESDAY.
A VIGOROUS SOUTHERN STREAM SHORTWAVE AHEAD OF A DEEPENING
EASTERN U.S. TROUGH WILL MOVE THROUGH THE REGION SATURDAY
MORNING, BRINGING PRECIPITATION TO THE REGION. AT THE ONSET TIME
OF THIS PRECIPITATION AROUND DAYBREAK SATURDAY, TEMPERATURES
WILL BE IN THE MID 20S TO LOWER 30S ACROSS THE CWA. A WEAK WARM
NOSE IS EVIDENT IN THE MODEL SOUNDINGS SUGGESTING THAT
PRECIPITATION WILL TRANSITION FROM SNOW, TO SLEET, TO
POTENTIALLY FREEZING RAIN IN THE SOUTHERN PARTS OF THE CWA.
TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING BY LATE MORNING
INTO THE EARLY AFTERNOON ALLOWING ALL PRECIPITATION TO CHANGE
OVER TO RAIN. THE LIMITED DURATION OF FROZEN/FREEZING
PRECIPITATION AND THE LIMITED QPF OVERALL FROM HAVING TO
OVERCOME AN ANTECEDENT DRY AIR MASS, WILL LIMIT ICE/SNOW
ACCUMULATIONS. NONETHELESS, COULD CERTAINLY SEE A SCENARIO WHERE
A WINTER WEATHER ADVISORY WILL BE WARRANTED WITH LATER
FORECASTS FOR MUCH OF THE CWA DURING THE LATE FRIDAY
NIGHT/SATURDAY MORNING TIME FRAME. TEMPERATURES SHOULD TOP OUT
IN THE UPPER 30S TO LOWER 40S BY AFTERNOON WITH JUST WEAK
WEDGING. QPF LOOKS TO BE IN THE 1/4 TO 1/3 INCH RANGE, THUS AN
INCH OR SO OF SNOW/SLEET/FREEZING RAIN MIXTURE WILL BE POSSIBLE
DURING THE MORNING HOURS.
THE PASSAGE OF THIS INITIAL SHORT WAVE WILL QUICKLY RESULT IN
FURTHER DEEPENING OF THE UPPER TROUGH ACROSS THE EASTERN U.S.
AND ALSO BRING THE FIRST SURGE OF WHAT WILL PROVE TO BE THE
COLDEST ARCTIC AIR TO VISIT THIS REGION IN SEVERAL YEARS.
PRECIPITATION ALONG/EAST OF THE BLUE RIDGE WILL MOSTLY END BY
SATURDAY EVENING AND TRANSITION TO TYPICAL UPSLOPE SNOW SHOWERS.
ON MONDAY, THE FIRST OF TWO BRUTALLY COLD SURGES OF ARCTIC AIR
WILL SETTLE OVER THE AREA IN THE FORM OF A 1044MB ARCTIC HIGH.
THIS FIRST SURGE WILL PALE IN COMPARISON TO THE NEXT MIDWEEK
SURGE. LOOK FOR A NON-DIURNAL TEMPERATURE TREND ON MONDAY WITH
STRONG COLD ADVECTION ALL DAY AS 850MB TEMPERATURES PLUMMET FROM
-4C EARLY IN THE DAY TO NEARLY -20C BY THE END OF THE DAY.
/CONFIDENCE LEVELS IN FORECAST PARAMETERS/
- MODERATE TO HIGH CONFIDENCE IN TEMPERATURES,
- MODERATE CONFIDENCE IN PRECIPITATION PROBABILITIES,
- MODERATE CONFIDENCE IN WIND SPEED, HIGH CONFIDENCE IN WIND
DIRECTION.
LONG TERM /TUESDAY THROUGH THURSDAY/
AS OF 245 PM EST THURSDAY...
KEY MESSAGES:
1). BITTERLY COLD WITH DANGEROUSLY LOW WIND CHILLS THROUGH THE
PERIOD.
2). POTENTIAL SNOW EVENT JUST BEHIND THIS PERIOD...NEED TO WATCH
CLOSELY.
TRULY ONE OF THE COLDEST AIR MASSES TO VISIT THE REGION IN MANY
YEARS WILL SPREAD ACROSS MUCH OF THE EASTERN U.S. DURING THE MID
PART OF NEXT WEEK. LOOKING FOR 850 MB TEMPERATURES TO RANGE
ANYWHERE FROM -20C TO -25C FROM THE MIDWEST TO THE MID-
ATLANTIC TO SETTLE OVER THE FORECAST AREA AS A 1050+ MB SURFACE
HIGH DRIFTS SOUTHEAST OUT OF CANADA BY MIDWEEK. A LARGE CORE OF
-30C TEMPERATURES IS NOTED WITHIN THE CENTER OF THIS FRIGID AIR
MASS, LARGER THAN I HAVE SEEN IN SEVERAL YEARS. THIS WILL
EVENTUALLY BE VERY CLOSE TO THE CWA MIDWEEK.
LOOK FOR MULTIPLE DAYS WITH HIGHS WELL BELOW FREEZING AND LOWS
NEAR TO EVEN BELOW ZERO DURING THE LATER HALF OF THE WEEK. PLAN
ACCORDINGLY FOR SOME OF THE COLDEST TEMPERATURES OF LONG
DURATION IN SEVERAL YEARS. THIS WILL BE COLDER THAN THE SPELL
DURING CHRISTMAS 2022. WIND CHILLS WILL BE DANGEROUSLY LOW
MULTIPLE MORNINGS IN A ROW.
FINALLY, KEEPING AN EYE ON A POTENTIAL WINTER STORM FOR NEXT
WEEKEND. WILL LEAVE THAT DISCUSSION FOR LATER.
/CONFIDENCE LEVELS IN FORECAST PARAMETERS/
- HIGH CONFIDENCE IN TEMPERATURES,
- MODERATE CONFIDENCE IN PRECIPITATION PROBABILITIES,
- HIGH CONFIDENCE IN WIND DIRECTION AND SPEED.
AVIATION /20Z THURSDAY THROUGH TUESDAY/
AS OF 115 PM EST THURSDAY...
LATEST SURFACE OBSERVATIONS INDICATE WEST-SOUTHWESTERLY WINDFLOW
WITH OCCASIONAL GUSTS TO 30KT ACROSS THE MOUNTAINS, AND TO 25KT
ACROSS THE PIEDMONT. SCATTERED CEILINGS IN PLACE PER 18Z
VISIBLE SATELLITE IMAGERY, WITH BASES IN THE 5KFT TO 7KFT
RANGE.
PASSING DISTURBANCE THIS EVENING WILL BEGIN TO SHIFT WINDS TO
THE WEST-NORTHWEST BEGINNING AROUND 17/00Z. BRUNT OF THE
DISTURBANCE WILL BRING 40 TO 45KT GUSTS ALONG THE CREST OF THE
BLUE RIDGE FOR A FEW HOURS, MAINLY DURING THE 17/03Z TO THE
17/09Z TIMEFRAME, BEFORE ENERGY MOVES AWAY TO THE EAST, ALLOWING
WIND SPEEDS TO DIMINISH. NORTHWESTERLY WIND SHIFT WILL USHER
ACROSS THE MOUNTAINS LOW STRATOCU CEILINGS, WITH BASES IN THE
1KFT TO 3KFT RANGE AS FAR EAST AS THE CREST OF THE BLUE RIDGE.
CEILINGS WILL REMAIN VFR FURTHER EAST, BREAKING UP IN DOWNSLOPE
WINDFLOW. UPSLOPE SNOW SHOWERS WILL IMPACT BLF AND LWB WITH
VISIBILITIES THAT MAY FALL TO LESS THAN 1SM OVER SHORT PERIODS
OF TIME. SNOWFALL WILL OCCUR IN SPURTS BETWEEN 17/00Z THROUGH
17/12Z BEFORE TAPERING OFF AS HIGH PRESSURE APPROACHES FROM THE
WEST. CLOUDS WILL LIKEWISE DIMINISH FROM EAST TO WEST AFTER
17/12Z, WITH VFR CONDITIONS RETURNING FOR MOST OF THE AREA BY
17/18Z UNDER MOSTLY CLEAR SKIES.
AVIATION OUTLOOK...
CLOUDS WILL INCREASE AGAIN FRIDAY EVENING AS AN APPROACHING LOW
PRESSURE SYSTEM IS EXPECTED TO BRING WIDESPREAD PRECIPITATION
AND POOR FLYING CONDITIONS FRIDAY NIGHT AND SATURDAY ACROSS THE
REGION. SUB-VFR CONDITIONS WILL PERSIST THROUGH SUNDAY WITH
UPSLOPE SNOW SHOWERS IN THE MOUNTAINS.
MONDAY WILL BE UNSEASONABLY COLD, DRY AND VFR.
RNK WATCHES/WARNINGS/ADVISORIES
VA...WIND ADVISORY FROM 7 PM THIS EVENING TO 4 AM EST FRIDAY FOR
VAZ007-009>020-022>024-032>035.
NC...WIND ADVISORY FROM 7 PM THIS EVENING TO 4 AM EST FRIDAY FOR
NCZ001-002-018.
WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR WVZ042-043.
WINTER STORM WARNING UNTIL 7 AM EST FRIDAY FOR WVZ508.
SYNOPSIS...AMS/NF
NEAR TERM...AMS/NF
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS/NF
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