732
FXUS61 KRNK 091820
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
120 PM EST FRI DEC 9 2022
SYNOPSIS
UNSETTLED WEATHER IS EXPECTED THROUGH THE WEEKEND AS A
STATIONARY FRONT TO OUR SOUTH WILL CONTINUE TO BE THE FOCUS FOR
CLOUDS AND THE POTENTIAL FOR LIGHT RAIN, DRIZZLE AND FOG ACROSS
THE HIGHER ELEVATIONS ALONG THE BLUE RIDGE. TEMPERATURES WILL
REMAIN COOL WITH HIGHS IN THE 40S AND LOWS IN THE 30S. SOME OF
THE HIGHEST ELEVATIONS MAY FLIRT WITH FREEZING TONIGHT AND AGAIN
SUNDAY MORNING.
NEAR TERM /THROUGH TONIGHT/
AS OF 950 AM EST FRIDAY...
KEPT TEMPERATURES STEADY FOR THE REST OF THE DAY.
GRADUALLY ERODING COVERAGE OF LIGHT RAIN AND DRIZZLE ON RADAR,
BUT WITH EASTERLY FLOW UP TO 3-4KFT SHOWING ON THE GSO AND RNK
12Z SOUNDINGS NOT EXPECT TO CHANGE MUCH SO WILL MAINTAIN CLOUDS
WITH PATCHY FOG AND DRIZZLE FOR THE REST OF THE DAY. TRIMMED
THE CHANCE OF ANY MEASURABLE PRECIPITATION. SHORT RANGE MODELS
ALL INDICATED LITTLE CHANGE IN TEMPERATURES THROUGH THE
AFTERNOON.
PREVIOUS:
A WAVY FRONTAL BOUNDARY STRETCHES FROM TEXAS TO THE SOUTHERN
APPALACHIANS. IMAGINE A ROPE WITH SOMEONE STANDING ON THE END
AND WHIPPING IT, WAVES MOVING ALONG THE ROPE, EACH WAVE
REPRESENTING AREAS OF LOW PRESSURE WHICH PRODUCE CLOUDS AND
PRECIPITATION. THIS IS THE PATTERN THAT WE ARE GOING THROUGH,
OUR FORECAST AREA ON THE RECEIVING END OF THE ROPE, EACH RIPPLE
BRINGING A PERIOD OF MEASURABLE RAINFALL. IF THERE IS ANYTHING
NOTEWORTHY, THE WAVES HAVE BEEN GETTING WEAKER WITH TIME, THE
RAINFALL, ALTHOUGH EPISODIC, DIMINISHING IN TERMS OF OVERALL
RAIN AMOUNTS. NEVER THE LESS, IT'S RAIN, AND RAIN SEEMINGLY
POOPS EVERYONES PARTY, WHETHER IT BE A PARADE OR OTHERWISE.
FOR TODAY, THE GENERAL MODEL CONSENSUS IS TO MAINTAIN THE
ABUNDANT CLOUD COVER. RAIN, ALBEIT LIGHT, IS IN THE FORECAST,
BUT CHANCE FOR MEASURABLE IS SIGNIFICANTLY REDUCED COMPARED TO
THE LAST FEW DAYS. CURRENT THINKING IS TODAY'S HYDROMETEOR FORM
WILL BE MOSTLY DRIZZLE WITH THE GREATEST IMPACT TO AREAS ALONG
THE SOUTHERN BLUE RIDGE WHERE EASTERLY UPSLOPE FLOW MAY RESULT
IN A PERSISTENT DRIZZLE/FOG SCENARIO FOR PLACES LIKE FANCY GAP,
VA AND BLOWING ROCK, NC...THIS STRIP OF BLUE RIDGE PARKWAY
NOTORIOUS FOR UPSLOPE FOG AND DRIZZLE. ELSEWHERE THE WEATHER MAY
BE LESS OMINOUS, BUT STILL CLOUDY.
THERE IS ANOTHER "WAVE" ALONG THE PROVERBIAL ROPE HEADED OUR WAY
FOR TONIGHT, THIS ONE APPEARS THAT IT WILL TAKE THE FORM OF AN
UPPER DISTURBANCE THAT WILL MOVE FARTHER NORTH INTO THE OHIO
VALLEY AND GREAT LAKES, THE ENERGY HAVING LESS OF AN IMPACT AS A
LIFTING MECHANISM FOR OUR AREA. LATEST RADAR MOSAICS INDICATE AN
AREA OF RAIN OVER THE UPPER MID-WEST AND ANOTHER OVER THE LOWER
TENNESSE VALLEY...WITH LITTLE OR NO LINK IN BETWEEN. THIS
SUGGESTS WHATEVER COMES OUR WAY TONIGHT WILL BE LIGHT IN NATURE
WITH THE CRUX OF THE DYNAMIC LIFT COMING THROUGH AROUND
MIDNIGHT. AS SUCH, THE FORECAST REFLECTS THE HIGHEST CHANCE FOR
MEASURABLE RAINFALL FOR OUR FORECAST AREA AROUND THAT TIME.
TEMPERATURES THROUGH TONIGHT ARE EXPECTED TO REMAIN COOL, CLOUDS
PREVENTING MUCH OF A RISE TODAY, AND COOL AIR ADVECTION FROM THE
NORTHEAST-EAST MAINTAINING A STEADY INFLUX OF COOLER AIR FROM
THE COLDER LATITUDES. THERE IS A SLIGHT RISK OF SOME ICING LATE
TONIGHT FOR OUR NORTHERN CWA AT ELEVATIONS ABOVE 3000 FEET.
MODEL SOUNDINGS SUGGEST THERE WILL BE A LAYER OF NEAR FREEZING
AIR AT ABOUT 3000 FT ABOVE MSL THAT WILL MOVE INTO AREAS NORTH
OF THE PEAKS OF OTTER ALONG THE BLUE RIDGE. IF THIS MATERIALIZES
THERE MAY BE SOME LIGHT ICING IN THE TREES FOR AREAS LIKE
MONTEBELLO AND WINTERGREEN EARLY SATURDAY MORNING.
SHORT TERM /SATURDAY THROUGH MONDAY/
AS OF 400 AM EST FRIDAY...
MORE RAIN FOR THE WEEKEND...
AN UPPER LEVEL CLOSED LOW WILL CROSS THE GREAT LAKES AND
NORTHEASTERN US OVER THE WEEKEND, AND EVENTUALLY OFFSHORE INTO THE
NORTHERN ATLANTIC BY THE BEGINNING OF THE WORK WEEK. SURFACE HIGH
PRESSURE WILL BE SITUATED OVER EASTERN CANADA, AND WEDGE DOWN ALONG
THE EASTERN SLOPES OF THE APPALACHIAN MOUNTAINS. A COLD FRONT WILL
APPROACH THE MID ATLANTIC FROM THE WEST BY SUNDAY. SOUTHERLY FLOW
AHEAD OF THE FRONT WILL BRING IN MORE MOISTURE TO THE AREA, AND
INCREASES PRECIPITATION CHANCES FOR THE SECOND HALF OF THE WEEKEND.
AT THIS TIME, THE FRONT LOOKS TO MOVE FAIRLY QUICKLY, AND
PRECIPITATION CHANCES DECREASE BY SUNDAY NIGHT. UPPER LEVEL RIDGING
OVER THE EASTERN HALF OF THE US STARTS TO AMPLIFY AND SURFACE HIGH
PRESSURE BUILDS IN AGAIN BEHIND THE COLD FRONT FOR THE BEGINNING OF
THE WORK WEEK.
HIGH TEMPERATURES WILL BE IN THE LOW TO MID 40S FOR THE WEEKEND, AS
THE WEDGE LOOKS TO REMAIN IN PLACE. CLOUDY CONDITIONS WILL LIKELY
KEEP LOWS IN THE 30S, SO NOT MUCH OF A DIURNAL SPREAD.
FORECAST CONFIDENCE IS AVERAGE.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
AS OF 430 AM EST FRIDAY...
PRECIPITATION CHANCES INCREASE MIDWEEK...
THE UPPER LEVEL PATTERN WILL CONTINUE TO AMPLIFY, AS RIDGING BUILDS
OVER THE EASTERN US AND TROUGHING DEEPENS IN THE WESTERN AND CENTRAL
US, WITH A CLOSED UPPER LOW DEVELOPING THROUGH MIDWEEK. A STRONG
COLD FRONT AND SURFACE LOW PRESSURE SYSTEM ASSOCIATED WITH THE UPPER
TROUGH WILL MOVE THROUGH THE CENTRAL PLAINS AND TOWARDS THE
APPALACHIANS BY WEDNESDAY/THURSDAY. SURFACE HIGH PRESSURE WILL
REMAIN OVER EASTERN CANADA, PUSHING COOLER AIR INTO THE REGION, AND
ANOTHER SURFACE LOW LOOKS TO DEVELOP OVER THE GULF COAST STATES
DURING THIS SAME TIME FRAME, WHICH WILL BRING MORE WARM, MOIST AIR
INTO THE AREA. LONG RANGE MODELS ARE SHOWING DIFFERENCES IN THE
TIMING AND MOVEMENT OF THESE TWO SYSTEMS, WHICH WILL INFLUENCE WHAT
PRECIPITATION IMPACTS CAN BE EXPECTED FOR THE AREA. STILL A LOT OF
UNCERTAINTY WITH THIS SYSTEM, BUT AT THIS TIME, LOOKS TO BE VERY WET
FOR THE MIDDLE OF THE WEEK.
HIGH TEMPERATURES WILL BE IN THE 40S THROUGH THIS PERIOD, WITH LOWS
IN THE UPPER 20S AND 30S.
FORECAST CONFIDENCE IS AVERAGE THROUGH THE BEGINNING OF THE WEEK,
BUT LOW FOR MIDWEEK ONWARD, GIVEN MODEL DIFFERENCES IN TIMING AND
DEVELOPMENT OF FRONTAL SYSTEM.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
AS OF 110 PM EST FRIDAY...
WIDESPREAD IFR TO LIFR IN THE MOUNTAINS AND FOOTHILLS OF
VIRGINIA AND NORTH CAROLINA THIS AFTERNOON THROUGH SATURDAY.
SHORT WAVE CROSSING EAST INTO THE GREAT LAKES WAS PRODUCING RAIN
FROM CENTRAL WISCONSIN TO SOUTHERN INDIANA. THIS FEATURE WILL MOVE
EAST TONIGHT. AT THE SURFACE THE ASSOCIATED LOW PRESSURE SYSTEM
WILL REACH THE OHIO VALLEY BY SATURDAY MORNING THEN WEAKEN.
THIS PATTERN WILL ENHANCE THE SURFACE WEDGE THAT WAS ALREADY IN
PLACE OVER THE MID ATLANTIC REGION.
SURFACE AND LOW LEVEL WIND FROM THE EAST WILL KEEP IFR/LIFR CLOUDS
AND MVFR FOG AND PATCHY DRIZZLE OVER THE FOOTHILLS AND ALONG
THE BLUE RIDGE TONIGHT. HREF SHOWS IFR/LIFR STRATUS AND FOG
FILLING BACK IN OVER CENTRAL VIRGINIA AND NORTH CAROLINA,
INCLUDING AT KDAN AND KLYH AROUND 00Z/7PM THIS EVENING.
IN ADDITION, THE RAIN WITH THE SHORT WAVE WILL REACH WESTERN
VIRGINIA AND SOUTHERN WEST VIRGINIA THIS EVENING, CONTINUING
ACROSS THE AREA THROUGH SATURDAY MORNING.
BUFKIT FORECAST SOUNDINGS STILL SHOW LIGHT FREEZING RAIN
POTENTIAL IN THE HIGHER ELEVATIONS, ESPECIALLY IN THE ALLEGHNAY
HIGHLANDS AND ALONG THE BLUE RIDGE NORTH OF ROANOKE AFTER
MIDNIGHT. NO FREEZING RAIN NEEDED FOR AREA TAFS AT THIS TIME.
EXTENDED AVIATION DISCUSSION...
UNSETTLED WEATHER PATTERN IS EXPECTED TO PERSIST THROUGH THE
WEEKEND. THERE WILL BE A BREAK IN THE RAIN ON SATURDAY AFTERNOON
THEN MORE PRECIPITATION ARRIVES AGAIN FOR SATURDAY NIGHT AND
SUNDAY.
MONDAY AND TUESDAY ARE EXPECTED TO BE DRY AND WITH A DRIER AIR
MASS ADVECTING INTO THE AREA, VFR CONDITIONS WILL RETURN.
HOWEVER, A DEEP LOW PRESSURE SYSTEM WILL IMPACT THE REGION
IN THE WEDNESDAY-THURSDAY TIME FRAME WITH SUB- MVFR CONDITIONS
AND THE POTENTIAL FOR MIXED WINTER PRECIPITATION. MODELS HAVE
BEEN SLOWING DOWN THE ARRIVAL OF THIS SYSTEM.
RNK WATCHES/WARNINGS/ADVISORIES
VA...NONE.
NC...NONE.
WV...NONE.
SYNOPSIS...PM
NEAR TERM...AMS/PM
SHORT TERM...AS
LONG TERM...AS
AVIATION...AMS/PM
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