170
FXUS61 KRNK 180543
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1243 AM EST TUE FEB 18 2025
SYNOPSIS
QUIET WEATHER IS EXPECTED INTO TUESDAY AHEAD OF THE REGIONS
NEXT AREA OF LOW PRESSURE THAT IS EXPECTED TO TRACK ACROSS THE
GULF, AND UP THE SOUTHEAST ATLANTIC COASTLINE WEDNESDAY AND
WEDNESDAY NIGHT BRINGING WINTRY PRECIPITATION TO THE AREA.
NEAR TERM /THROUGH TODAY/
AS OF 615 PM EST SUNDAY...
KEY MESSAGE:
- TRANQUIL WEATHER FOR A CHANGE BUT ON THE COLDER SIDE OF
NORMAL
FORECAST ON TRACK AND SHOULD BE A QUIET NIGHT, WITH WINDS
SUBSIDING. HIGH CLOUDS STREAM INTO THE AREA FROM THE WEST, AND
ALSO COULD SEE SOME LEE/OROGRAPHIC CIRRUS LATER TONIGHT
ALONG/EAST OF THE APPALACHIANS.
PREVIOUS DISCUSSION...
SATELLITE IMAGES SHOWED SCATTERED STRATOCUMULUS OVER THE MOUNTAINS
AND LOCAL NATIONAL WEATHER SERVICE RADARS WERE DETECTING ONLY A FEW
SNOW SHOWERS LEFT IN WESTERN GREENBRIER COUNTY. THESE LOWER CLOUDS
WILL CONTINUE TO DISSIPATE THIS AFTERNOON.
HIGH CLOUDS SPREAD INTO THE MID ATLANTIC REGION FROM THE WEST
OVERNIGHT AND CLOUD COVER INCREASES ON TUESDAY. NOT MUCH COLD AIR
ADVECTION OVERNIGHT AND LITTLE CHANGE IN THE INTENSITY OF THE LOW-
LEVEL JET. EXPECT WIND SPEEDS TO WEAKEN AT LOWER ELEVATIONS, BUT
GUSTS OF 15 TO 25 KNOTS ON THE RIDGES TONIGHT. WIND SPEEDS CONTINUE
TO WEAKEN ON TUESDAY.
NO MAJOR CHANGES TO TEMPERATURES TONIGHT OR TUESDAY. ONCE CLOUDS
FILL IN TONIGHT, DROP IN TEMPERATURES IS EXPECTED TO SLOW.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
AS OF 1230 PM EST MONDAY...
KEY POINTS:
1. WINTER STORM WATCH WILL BE ISSUED
2. SNOW TO IMPACT THE AREA TUESDAY NIGHT INTO WEDNESDAY NIGHT
WITH GREATEST AMOUNTS OVER EASTERN PORTIONS.
3. VERY SMALL CHANCE OF A MIX OF SLEET OVER FAR SOUTHEAST PARTS
OF THE REGION.
4. SUB-ZERO WIND CHILLS ACROSS THE MOUNTAINS WEDNESDAY NIGHT
AND THURSDAY NIGHT, SINGLE DIGITS AND TEENS FOR WIND CHILLS OVER
PIEDMONT.
A LOOK AT THE 17 FEB 00Z NCEP ENSEMBLE MEAN 500MB GEOPOTENTIAL
HEIGHTS SHOW A CLOSED LOW OVER ND/MN TUESDAY EVENING WITH AN
ASSOCIATED LONGWAVE TROUGH EXTENDING SOUTH THROUGH CENTRAL CONUS.
SOUTHWEST FLOW IS EXPECTED ACROSS OUR REGION. FOR WEDNESDAY AND
WEDNESDAY NIGHT, THE LOW DEEPENS A BIT AND HEAD SOUTHEAST INTO THE
WESTERN GREAT LAKES REGION. THE ASSOCIATED TROUGH TRENDS SLIGHTLY
NEGATIVELY TILTED, EXTENDING SOUTHEAST INTO AL/GA AROUND
WEDNESDAY EVENING. FOR THURSDAY INTO THURSDAY NIGHT, THE CLOSED
IS EXPECTED TO HAVE TRANSITIONED INTO AN OPEN WAVE HEADING
ACROSS NEW ENGLAND THURSDAY EVENING. THE ASSOCIATED TROUGH IS
EXPECTED TO HEAD SOUTH IMMEDIATELY ALONG THE EAST COAST OF THE
US. FARTHER WEST, AN OTHER TROUGH BEGINS TO DEVELOP, EXTENDING
FROM THE DAKOTAS SOUTHWEST INTO THE FOUR CORNERS REGION.
AT THE SURFACE, A BROAD AREA OF HIGH PRESSURE IS EXPECTED TO
SITUATED OVER MT/ND/SD TUESDAY EVENING. ITS ASSOCIATED RIDGE AXIS
CURVES SOUTHEAST INTO THE MID-MISSISSIPPI RIVER VALLEY, AND THEN
EAST TO OVER THE MID-ATLANTIC REGION. AN INVERTED TROUGH IS EXPECTED
TO BE LOCATED OVER EAST TX NORTHEAST INTO WESTERN PORTIONS OF THE
TENNESSEE VALLEY. FOR WEDNESDAY INTO WEDNESDAY NIGHT, THE INVERTED
TROUGH MAKES PROGRESS EASTWARD ON WEDNESDAY. BY EARLY WEDNESDAY
EVENING, THE TROUGH DEVELOPS INTO A CLOSED LOW OFF THE GA/FL COAST.
WHILE RETROGRADED A BIT BY THE DEEPENING LOW, THE RIDGE AXIS
OVER THE MID-ATLANTIC REGION WEAKENS, BUT DOES NOT DISSIPATE
COMPLETELY. CONCURRENTLY, A WEAK TROUGH OF LOW PRESSURE IS
EXPECTED TO BE HEADING SOUTH OVER ONTARIO, ON THE EAST SIDE OF
THE BROAD SURFACE HIGH. FOR THURSDAY INTO THURSDAY NIGHT, THE
LOW THAT WAS OFF THE GA/FL COAST IS EXPECTED TO HAVE DEEPENED
EVEN MORE AND PROGRESSED QUICKLY NORTHEAST OFF THE US EAST COAST
AND BE SOUTHEAST OF THE ME BY THE EVENING HOURS. THE WEAK WAVE
THAT WAS HEADING SOUTH THROUGH ONTARIO ON WEDNESDAY, IS
EXPECTED TO BE NEAR OH/PA/NY BY THE EVENING HOURS AS WELL.
LOOKING WEST, THE AXIS OF THE BROAD UPPER RIDGE IS EXPECTED TO
START EXPANDING EASTWARD AGAIN AFTER ITS BRIEF RETROGRADE.
A LOOK AT THE 17 FEB 00Z NAEFS ENSEMBLE SITUATIONAL AWARENESS DATA
SHOWS 850MB TEMPERATURES ON TUESDAY EVENING RANGING FROM -8C TO -4C,
N-S. BY WEDNESDAY MORNING, THE RANGE IS SIMILAR, BUT ORIENTED MORE
NW-SE. BY WEDNESDAY EVENING, THE RANGE BROADENS TO -8C TO -2C, NW-
SE. THURSDAY MORNING, VALUES DECREASE SIGNIFICANTLY TO -15C TO -8C,
NW-SE. THESE VALUES CORRESPOND TO THE 2.5 TO 10 PERCENTILE OF THE 30-
YEAR CFSR CLIMATOLOGY. BY THE START OF THURSDAY NIGHT, VALUES ARE
EVEN LOWER, RANGING FROM -16C TO -13C, NW-SE. THESE VALUES
CORRESPOND TO THE 1 TO 10 PERCENTILE OF THE 30-YEAR CLIMATOLOGY. THE
LOWEST DEPARTURES FROM NORMAL ARE NEAR THE VA/NC BORDER.
THE ABOVE WEATHER PATTERNS OFFER THE FOLLOWING FORECAST. CLOUD COVER
WILL BE ON THE INCREASE TUESDAY NIGHT IN ADVANCE OF AN INVERTED
TROUGH WHICH WILL EXTEND FROM THE MID TO LOWER MISSISSIPPI VALLEY.
ENOUGH LOW LEVEL ISENTROPIC ADVECTION OF MOISTURE IS EXPECTED BY THE
EARLY MORNING HOURS OF THURSDAY TO FOR PRECIPITATION TO START OVER
MAINLY WESTERN AND NORTHERN SECTIONS OF THE REGION. TIMING OF THIS
ONSET IS AROUND THREE HOURS LATER THAN MOST SOLUTIONS OFFERED 24
HOURS AGO.
PRECIPITATION IS EXPECTED TO CONTINUE OVERSPREADING THE REGION ON
WEDNESDAY AS THE WEATHER SYSTEM HEADS EASTWARD. MUCH LIKE THE
SOLUTIONS OF YESTERDAY, THE FOCUS FOR THE BEST ENERGY IS EXPECTED TO
REMAIN SOUTH OF THE AREA NEAR GA/FL. A KEY ITEM WHICH DOES DIFFER
COMPARED TO 24 HOURS AGO IS THE DEGREE TO WHICH THIS SOUTHERN STREAM
SYSTEM DOES NOT DIRECTLY INTERACT WITH THE SHORTWAVE TROUGH HEADING
SOUTH THROUGH ONTARIO. THIS NORTHERN STREAM SYSTEM IS IN BETTER
AGREEMENT TODAY FOR MAKING ITS PRESENCE KNOWN MORE WITHIN THE LATE
WEDNESDAY NIGHT THROUGH THURSDAY TIME FRAME. THIS TIMING SHOULD
YIELD AN EVENT ON WEDNESDAY THAT LASTS PERHAPS 18 HOURS EARLY
EARLY WEDNESDAY MORNING THROUGH THE START OF WEDNESDAY EVENING
WHICH SHOULD IMPACT THE ENTIRE REGION, JUST WITH LESS OF A PUNCH
THAN OUR SOLUTION FROM YESTERDAY. AFTER A BREAK OF SIX TO NINE
HOURS, OUR NEXT SYSTEM WILL IMPACT PRIMARILY AREAS WEST OF THE
CREST OF THE BLUE RIDGE WITH UPSLOPE SNOW SHOWERS. IMPACTS EAST
OF THE CREST OF THE BLUE RIDGE SHOULD BE MINIMAL, BUT HAVE THE
GREATEST POTENTIAL ACROSS OUR NORTHEAST SECTIONS WHERE SOME
POTENTIAL INTERACTION BETWEEN THIS TWO SYSTEMS CANNOT BE RULED
OUT.
REGARDING THE PRECIPITATION TYPE ON WEDNESDAY, WE ARE STILL FAVORING
A PRIMARILY SNOW FORECAST FOR THE VAST MAJORITY OF THE REGION.
HOWEVER, WITHOUT THE IMMEDIATE INTERACTION WITH THE SECOND SYSTEM
OUR SNOWFALL TOTALS ARE LOWER. ANOTHER CHANGE IS THE AMOUNT OF WHAT
WAS ALREADY FORECAST TO BE MINIMAL AMOUNTS OF FREEZING RAIN AND/OR
SLEET. THE LATEST TRENDS ARE FOR EVEN LESS OF OUR REGION TO HAVE
WINTRY PRECIPITATION OTHER THAN SNOW. NOW, AT BEST WE ARE
CONSIDERING SOME POCKETS OF SLEET WITH THE SNOW ACROSS THE FAR
SOUTHEASTERN PORTION OF THE REGION.
A LOOK AT THE OUTPUT FROM DESI FROM THE 17 FEB 13Z RUN USING THE NBM-
CONUS DATASET OFFERS A MUCH DIFFERENT PICTURE TODAY THAN 24 HOURS
AGO. YESTERDAY MOST OF THE REGION HAD OVER A 50 PERCENT PROBABILITY
OF RECEIVING OVER 4 INCHES OF SNOW FROM WEDNESDAY MORNING
THROUGH THURSDAY MORNING. LOOKING AT THE SAME PARAMETERS TODAY
SHOWS A DIFFERENT PICTURE. NO AREA WITHIN THE FORECAST AREA HAS
A GREATER THAN 50 PERCENT PROBABILITY OF RECEIVING FOUR OR MORE
INCHES THROUGH THURSDAY MORNING. WHEN LOOKING FOR AN AREA WHERE
TWO OR MORE INCHES ARE EXPECTED, THE REGION IS ROUGHLY THOSE
LOCATIONS ALONG AND EAST OF A REIDSVILLE TO MARTINSVILLE TO
LYNCHBURG LINE WITH THE GREATEST PROBABILITY EAST OF DANVILLE.
SNOWFALL ACROSS THE MOUNTAINS FROM THE SECOND SYSTEM IS EXPECTED TO
RANGE FROM TRACE AMOUNTS TO PERHAPS AROUND AN INCH ACROSS WESTERN
GREENBRIER COUNTY.
TEMPERATURES BEHIND THE SYSTEM ARE EXPECTED TO DROP CONSIDERABLY.
LOW TEMPERATURES WEDNESDAY NIGHT ARE EXPECTED TO BE AROUND 10 TO 15
ACROSS THE MOUNTAINS AND 15 TO 20 ACROSS THE PIEDMONT. SIMILAR
TEMPERATURES ARE EXPECTED THURSDAY NIGHT. WINDS WILL BECOME GUSTY
LATE WEDNESDAY NIGHT AND REMAIN GUSTY THROUGH THURSDAY NIGHT. COLD
WEATHER ADVISORIES MAY BE NEED BOTH THESE NIGHTS FOR PARTS OF THE
MOUNTAINS (THURSDAY NIGHT MORE SO THAN WEDNESDAY NIGHT) AS WIND
CHILLS DROP TO OR BELOW -5F.
CONFIDENCE IN THE ABOVE WEATHER SCENARIO IS MODERATE.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 1230 PM EST MONDAY...
KEY POINTS:
1. MAINLY DRY AND TRENDING MILDER FRIDAY AND SATURDAY.
2. NEXT POSSIBLE WEATHER MAKER SUNDAY/MONDAY BUT CONFIDENCE IS LOW.
A LOOK AT THE 17 FEB 00Z NCEP ENSEMBLE MEAN 500MB GEOPOTENTIAL
HEIGHTS SHOWS NEAR ZONAL FLOW ACROSS OUR REGION. ADDITIONALLY, AN
EXITING TROUGH WILL BE OVER NEWFOUNDLAND-LABRADOR, AND ANOTHER
TROUGH WILL BE MAKING HEADWAY EASTWARD OVER THE UPPER MISSISSIPPI
RIVER VALLEY, SOUTHWEST INTO THE FOUR CORNERS REGION. FOR SATURDAY,
WHAT WAS DEPICTED AS ONE BROAD AND LENGTHY TROUGH ON FRIDAY, IS
EXPECTED TO HAVE CHARACTERISTICS OF A SHORTWAVE TROUGH MOVING ACROSS
THE GREAT LAKES/LOWER OHIO VALLEY, AND A SHORTWAVE TROUGH OVER TX.
ADDITIONALLY, UPSTREAM OF THE GREAT LAKES SHORTWAVE TROUGH, AN
ADDITIONALLY SHORTWAVE TROUGH IN THE NORTHERN STREAM IS EXPECTED TO
BE MOVING THROUGH MT. FOR SUNDAY, THE GREAT LAKES SHORTWAVE TROUGH
IS EXPECTED TO HAVE PROGRESSED OFF THE COAST OF NEW ENGLAND BY
SUNDAY EVENING. THE TX AND MT SHORTWAVE TROUGH ARE EXPECTED TO MERGE
TROUGH CONSTRUCTIVE INTERFERENCE AN YIELD A DEVELOPING LONGWAVE
TROUGH EXTENDING FROM THE GREAT LAKES TO THE LOWER MISSISSIPPI
VALLEY. ON MONDAY, THE DEVELOPING LONGWAVE TROUGH DEVELOPS EVEN
MORE, SHIFTS EAST, AND EXTENDS FROM QUEBEC TO FLORIDA.
AT THE SURFACE, THE CENTER OF SURFACE HIGH PRESSURE WILL SHIFT EAST
TO OVER IL/IN BY FRIDAY EVENING. ON SATURDAY, LITTLE CHANGE IS
EXPECTED REGARDING THE CENTRAL LOCATION OF THE HIGH. HOWEVER, THE
OVERALL REGION OF HIGH PRESSURE IS EXPECTED TO EXPAND INTO THE
SOUTHEAST US. FOR SUNDAY, THE CENTER OF THE HIGH SHIFTS TO OVER THE
SOUTHERN APPALACHIANS. CONCURRENTLY, TROUGH STARTS TO DEVELOP OVER
THE UPPER MISSISSIPPI RIVER VALLEY, AND TROUGH IS NOTED ON THE
SOUTHEAST SIDE OF THE HIGH PRESSURE, JUST EAST OF FL. FOR MONDAY,
THE TROUGH THAT WAS DEVELOPING OVER THE UPPER MISSISSIPPI RIVER
VALLEY IS EXPECTED TO HEAD SOUTHEAST INTO THE GREAT LAKES REGION.
THE CENTER OF THE SURFACE HIGH RETROGRADES TO THE LOWER MISSISSIPPI
RIVER VALLEY. THE LOW THAT WAS DEVELOPING ON THURSDAY OFF THE COAST
OF FL GETS LOST IN THE ENSEMBLE AVERAGING, BUT WITH THE SHORTWAVE
TROUGH HEADING SOUTHEAST TOWARDS THE MID-ATLANTIC REGION, IT
WOULD OFFER A WEAKNESS IN THE PRESSURE FIELD TO PERHAPS PROMPT A
NORTHWARD PROGRESSION.
A LOOK AT THE 17 FEB 00Z NAEFS ENSEMBLE SITUATIONAL AWARENESS DATA
SHOWS 850MB TEMPERATURES ON FRIDAY MODERATING A BIT, REACHING -8C TO
-6C, NW-SE BY THE EARLY EVENING. FRIDAY NIGHT, VALUES TREND SLIGHTLY
HIGHER, REACHING -6C TO -4C, N-S BY DAYBREAK SATURDAY. ON SATURDAY
VALUES HOLD CLOSE TO THE SAME VALUES. A SMALL INCREASE IS EXPECTED
SATURDAY NIGHT, REACHING -6C TO -2C BY DAYBREAK SUNDAY. ON SUNDAY,
VALUES CLIMB SLIGHTLY TO -3C TO -1C, N-S BY THE EVENING HOURS.
SUNDAY NIGHT, THE SLIGHT WARMING TREND CONTINUES WITH VALUES BY
DAYBREAK MONDAY OF -2C TO 0C, N-S. INCREASING VALUES CONTINUE MONDAY
WITH NUMBERS BY SUNSET OF -1C TO +1C, N-S.
THE ABOVE WEATHER PATTERNS OFFER THE FOLLOWING FORECAST. RESIDUAL,
BUT WEAKER, NORTHWEST FLOW UPSLOPE CONDITIONS MAY STILL PROVIDE FROM
SOME LIGHT SNOW/FLURRIES OVER PARTS OF SE WV ON FRIDAY. THE
REMAINDER OF THE REGION IS EXPECTED TO BE PRECIPITATION FREE. HIGH
PRESSURE OVER THE REGION ON SATURDAY IS EXPECTED TO KEEP THAT DAY
PRECIPITATION-FREE AS WELL. QUESTIONS ARRIVE FOR SUNDAY AND THE
IMPACTS OF THE LONGWAVE TROUGH THE ENSEMBLES WERE NOTING DEVELOPING
OVER OR JUST WEST OF THE REGION. BY MONDAY, THE AXIS OF THIS TROUGH
IS EXPECTED TO BE OVER THE AREA. ACCORDINGLY, AN SURFACE BASED
FEATURES LIKELY WOULD BE FARTHER SOUTHEAST OF THE REGION.
TEMPERATURES THROUGH THE PERIOD ARE EXPECTED TO GRADUALLY TREND
MILDER.
CONFIDENCE IN THE ABOVE WEATHER SCENARIO IS MODERATE THROUGH
SATURDAY, THEN TRENDS LOW FOR SUNDAY/MONDAY.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AS OF 1230 AM EST TUESDAY...
VFR CONDITIONS LOOK TO REMAIN AT ALL TERMINALS THROUGH THE TAF
PERIOD, WITH SOME BROKEN TO OVERCAST MID LEVEL CLOUDS PUSHING
OVER THE REGION TONIGHT, AND INTO THE DAYTIME HOURS ON TUESDAY.
THESE CLOUDS LOOK TO REMAIN ABOVE 5000 FT AT THIS TIME. A MORE
DENSE CLOUD DECK LIKELY BRINGING MVFR CIGS TO THE REGION LOOKS
TO APPROACH WESTERN TAF SITES JUST AFTER 06 UTC WEDNESDAY AS THE
NEXT WINTER STORM APPROACHES THE REGION. OVERALL, IDEAL FLYING
CONDITIONS ARE EXPECTED TODAY, WITH NORTHWESTERLY TO WESTERLY
WINDS AT AROUND 5-10 MPH FORECAST FOR MUCH OF THE DAY. A
TRANSITION TO NORTHERLY WINDS LOOKS TO START JUST PRIOR TO 06
UTC WEDNESDAY AT ALL TERMINALS AS SUBLTE WEDGING LOOKS TO
DEVELOP ACROSS THE LEE OF THE APPALACHIANS.
AVERAGE CONFIDENCE FOR CEILING, VISIBILITY AND WIND.
EXTENDED AVIATION OUTLOOK
ANOTHER STORM WILL BRING SNOW FOR MOST OF THE AREA WED-INTO
EARLY THU AND SUB- VFR CONDITIONS WITH THE MID ATLANTIC BEING
SIGNIFICANTLY IMPACTED. THINGS CLEAR OUT TO END THE WEEK, BUT
EXPECT SUB-VFR CONDITIONS TO CONTINUE IN THE MOUNTAINS WITH
SNOW SHOWERS INTO LATE THU, POSSIBLY FRIDAY ALONG WITH GUSTY
WINDS.
DRY, VFR WEATHER IS EXPECTED SATURDAY.
RNK WATCHES/WARNINGS/ADVISORIES
VA...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR VAZ035-043>047-058-059.
NC...WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY
MORNING FOR NCZ004>006.
WV...NONE.
SYNOPSIS...AMS/WP
NEAR TERM...AMS/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...EB/WP
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