049
FXUS61 KRLX 270310
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1010 PM EST FRI FEB 26 2021
SYNOPSIS
SYSTEM BRINGS RAIN WITH A HIGHER ELEVATION WINTRY MIX TONIGHT
INTO TOMORROW. A STRONGER WAVE CROSSES SUNDAY, FOLLOWED BY A
COLD FRONT SUNDAY NIGHT.
NEAR TERM /THROUGH SATURDAY/
AS OF 1005 PM FRIDAY...
THE FORECAST REMAINS IN TACT AND ONLY HAD TO FRESHEN UP POPS
AND QPF TO REFLECT CURRENT OBSERVATIONS AND TRENDS.
TEMPERATURES SEEMED TO HAVE BOTTOMED OUT ALREADY, THEREFORE
RAISED THEM BY A FEW DEGREES OVER THE NEXT SEVERAL HOURS TO
REFLECT THE WARMING TREND EXPECTED TO TAKE PLACE. A LOT OF THE
WINTRY PRECIPITATION HAS SETTLED DOWN BUT THERE ARE SOME CHANCES
LEFT AROUND COLD SPOTS TO RECEIVE FREEZING RAIN AND THE HIGHER
ELEVATIONS ARE STILL RECEIVING LIGHT SNOWFALL. THEREFORE, THE
WINTER WEATHER ADVISORY WILL BE CONTINUED FOR NOW.
AS OF 705 PM FRIDAY...
THE FORECAST REMAINS ON TRACK AND ONLY HAD TO MODIFY POPS JUST
SLIGHTLY TO MATCH CURRENT OBSERVATIONS AND TRENDS.
AS OF 455 PM FRIDAY...
MADE SOME CHANGES TO THE FORECAST OVER AREAS NEAR AND ALONG THE
MOUNTAINS, ESPECIALLY IN RALEIGH AND FAYETTE COUNTIES.
TEMPERATURES HAVE DROPPED TO 34F AND A WINTRY MIX HAS BEGAN,
THEREFORE HAD TO ADD IN SOME SNOW AND RAIN TO THE MIX AS WELL AS
SOME FREEZING RAIN TONIGHT AS SURFACE TEMPERATURES MAY CONTINUE
TO DROP BY A FEW DEGREES. TEMPERATURES HAVE BEEN UPDATED TO
REPRESENT CURRENT OBSERVATIONS AND TRENDS. AS WARMING TAKES
PLACE NEAR OR SLIGHTLY AFTER MIDNIGHT THE CHANGEOVER TO AN ALL
RAIN REGIME WILL COMMENCE. JUST SOME PATCHY ICE ACCUMULATIONS
ARE LIKELY WHICH MAY POSE A HAZARDOUS TRAVEL THREAT, HOWEVER THE
SNOW AMOUNTS UP TO 1 INCH OF SNOWFALL COULD ALSO POSE A THREAT
TO TRAVEL AS WELL ON UNTREATED ROADWAYS OR WALKWAYS IN THE AREAS
UPDATED IN THE FORECAST.
AS OF 230 PM FRIDAY...
PRECIPITATION IS MOVING IN FROM THE SOUTHEAST THIS AFTERNOON AS
A DISTURBANCE PASSES THROUGH THE AREA. MOST OF THE PRECIPITATION
WILL FALL AS RAIN, HOWEVER THERE MAY BE A RAIN/SNOW MIX IN THE
MOUNTAINS, GRADUALLY TRANSITIONING TO MOSTLY RAIN BY TOMORROW
MORNING. A MIX OF WINTRY PRECIPITATION MAY OCCUR IN THE
MOUNTAINS DURING THIS TRANSITION, WITH FREEZING RAIN OR SLEET
POSSIBLE. UP TO AN INCH OF SNOW WILL BE POSSIBLE ALONG THE
NORTHEAST MOUNTAINS WITH UP TO 3 TO 4 INCHES ALONG THE HIGHEST
PEAKS. HAVE LOWERED THE ICE ACCUMULATIONS THE PREVIOUS FORECAST
TO A FEW TENTHS OF AN INCH AS THE CHANCE FOR FREEZING RAIN IS
LOOKING LESS LIKELY WITH TEMPERATURES POSSIBLY STAYING MORE ON
THE WARMER SIDE, HOWEVER STILL NOT RULING FREEZING RAIN OUT
COMPLETELY AS AREAS THAT DO REACH COOL ENOUGH MAY HAVE THE
POTENTIAL FOR SOME TO OCCUR. NOT EXPECTING MUCH IN TERMS OF
IMPACTS WITH THE ICE, BUT A LIGHT GLAZE COULD STILL BE POSSIBLE
FOR THE AREAS UNDER THE WINTER WEATHER ADVISORY AND COULD LEAD
TO SLICK ROAD CONDITIONS, SO WILL KEEP THE ADVISORY IN EFFECT
THROUGH TONIGHT. BY TONIGHT, THE HIGHEST PRECIPITATION CHANCES
WILL MOSTLY BE ALONG THE EASTERN PORTION OF THE AREA, BUT HAVE
KEPT CHANCES OF PRECIP IN FOR THE REMAINDER OF THE AREA AS
MOISTURE LINGERS AND COULD CONTINUE TO PRODUCE RAIN. IT IS
POSSIBLE THERE MAY BE A BREAK OR A PERIOD OF LIGHTER
PRECIPITATION LATE THIS EVENING/EARLY TONIGHT FOR THIS AREA.
LATER TONIGHT ANOTHER DISTURBANCE MOVES IN, BRINGING INCREASING
PRECIPITATION CHANCES AGAIN FROM THE SOUTH AND MOSTLY AFFECTING
THE SOUTH/SOUTHEASTERN PORTIONS OF THE AREA. CHANCES WILL
DIMINISH BY TOMORROW MORNING AND MUCH OF THE AREA IS EXPECTED TO
HAVE A BREAK IN RAIN FOR THE MAJORITY OF THE DAY TOMORROW. THE
SOUTHERN AND SOUTHEASTERN PORTIONS WILL CONTINUE TO HAVE A
CHANCE FOR RAIN AS MOISTURE CONTINUES TO LINGER ALONG THESE
AREAS, GRADUALLY DECREASING THROUGHOUT THE DAY. WITH THESE
DISTURBANCES, CURRENTLY EXPECTING ACCUMULATIONS UP TO AN INCH
FOR THE VERY SOUTHEASTERN PORTIONS OF THE AREA, GRADUALLY
DECREASING UP TO LESS THAN A TENTH OF AN INCH IN THE
NORTHWEST. NOT EXPECTING MUCH IF ANY WATER ISSUES THROUGH
SATURDAY, WITH MORE OF A FLOOD THREAT POSSIBLE FOR THE SECOND
HALF OF THE WEEKEND.
TEMPERATURES WILL BE ABOVE NORMAL TONIGHT AND TOMORROW WITH LOWS
TONIGHT IN THE LOW TO MID 40S FOR THE LOWLANDS AND MID 20S TO
MID 30S FOR THE HIGHER ELEVATIONS. MUCH OF THE AREA WILL BE
IN MID 50S TO LOW 60S TOMORROW, WITH MID 40S TO 50S FOR THE
HIGHER ELEVATIONS.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/
AS OF 335 AM FRIDAY...
WAVE AFTER WAVE BRINGS COPIOUS RAINFALL THIS PERIOD WHICH,
TOGETHER WITH THE WET ANTECEDENT CONDITIONS, SPELLS SOME
POTENTIAL FOR FLOODING.
THE FIRST IN A SERIES OF WAVES WILL BE ONGOING SATURDAY
MORNING ACROSS MAINLY SOUTHEAST PORTIONS OF THE FORECAST AREA.
TEMPERATURES AND DEW POINTS CLIMB JUST ABOVE FREEZING BY THE
START OF THE PERIOD, 12Z SATURDAY, ALONG THE HIGHEST RIDGES AND
EASTERN SLOPES, AS THE LAST OF THE COLD AIR IS ERODED THERE BY
MODERATELY STRONG LOW LEVEL SOUTH TO SOUTHWEST FLOW.
MOISTURE FLUX AND FORCING MAXIMIZE ACROSS SOUTHEAST PORTIONS OF
THE FORECAST AREA, WHERE PW VALUES CLIMB TO AROUND AN INCH,
RAINFALL TOTALS COULD APPROACH THAT OVER A ROUGHLY 12-HOUR
PERIOD ENDING MIDDAY SATURDAY.
WEAK RIDGING BUILDS INTO THE MIDDLE OHIO VALLEY SATURDAY, AND
THE RAIN WILL GRADUALLY DECREASE FROM NORTHWEST TO SOUTHEAST,
RESULTING IN A BRIEF LULL SATURDAY AFTERNOON AND EVENING,
ESPECIALLY NORTH.
THE NEXT WAVE APPROACHES SATURDAY NIGHT, AND THEN CROSSES
SUNDAY MORNING. THIS WAVE IS PROGGED TO BE STRONGER AND MORE
AMPLIFIED, AND THE AXIS OF HEAVIER RAINFALL SETS UP FARTHER
NORTH COMPARED TO ITS PREDECESSOR, A KEY FACTOR IN THE
HYDROLOGIC ASSESSMENT THIS WEEKEND. THE MODEL ENVELOP FOR THE
AXIS OF HEAVIEST RAINFALL WITH THIS WAVE RANGES FROM CENTRAL TO
NORTHWEST PORTIONS OF THE FORECAST AREA, WITH AN H85 50 KT FEED
CRANKING PW VALUES TO 1.25 INCHES OR BETTER.
SKINNY ELEVATED CAPE CAN DEVELOP ALONG AND JUST SOUTH OF THE
AXIS OF THE AXIS OF HEAVIEST MOISTURE, WHERE H85 THETA E GETS TO
320K OR BETTER WITH DEW POINTS APPROACHING 10C AT THAT LEVEL.
THUS HAVE ADDED THE SLIGHT CHANCE FOR THUNDER SATURDAY NIGHT
THROUGH SUNDAY ACROSS MAINLY CENTRAL AND SOUTHEASTERN PORTIONS
OF THE FORECAST AREA.
A COLD FRONT CROSSES THE AREA FROM NORTHWEST TO SOUTHEAST SUNDAY
AFTERNOON AND NIGHT, GENERALLY PUSHING THE RAIN TO THE SOUTH AND
EAST. HOWEVER, ONE LAST WAVE ALONG THAT COLD FRONT MAY BRING ONE
LAST ROUND OF HEAVY RAINFALL ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA SUNDAY NIGHT. THIS MAY BE ENOUGH TO KICK STREAMS
OVER THE EDGE.
THE STORM TOTAL QPF FOR TODAY THROUGH SUNDAY NIGHT IS CLOSE TO
CENTRAL GUIDANCE, AND REFLECTS AMOUNTS RANGING FROM CLOSE TO AN
INCH NORTHWEST TO OVER THREE INCHES ACROSS SOUTHEAST PORTIONS
OF THE AREA, ALTHOUGH SOME MODELS DEPICT A DISTINCT NORTHERN
MAXIMA OVER NORTHERN OR CENTRAL PORTIONS OF THE AREA, WITH
AMOUNTS OF TWO TO IN SOME CASES THREE INCHES OR BETTER. THIS
COULD LEAD TO EXCESSIVE RAINFALL BY SUNDAY, ESPECIALLY GIVEN
SATURATED CONDITIONS AND STRONG STREAM AND RIVER FLOW COMING OUT
OF THE RECENT WINTER WEATHER STRETCH.
VERY DRY AIR BRINGS STOUT CLEARING FROM NORTHWEST TO SOUTHEAST
ON MONDAY.
TEMPERATURES CLOSE TO CENTRAL GUIDANCE, EXCEPT A BIT HIGHER
SOUTH OF THE FRONT ON SUNDAY.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
AS OF 1130 AM FRIDAY...
MODELS SHOWING A COLD FRONT PUSHING SOUTH OF THE AREA ON MONDAY,
WITH A REINFORCING MOISTURE STARVED COLD FRONT FROM PUSHING
THROUGH LATER MONDAY. THERE IS SOME DISAGREEMENT IN THE MODELS
WITH THE INTENSITY OF THE COLD AIR THAT MOVES IN BEHIND THIS
SECOND FRONT MONDAY NIGHT, WITH THE GFS BEING COLDER THAN THE
CANADIAN OR ECMWF.
A HIGH PRESSURE SYSTEM WILL THEN BUILD ACROSS THE AREA FOR
TUESDAY.
MODELS THEN DIVERGE CONSIDERABLY FOR THE NEXT SYSTEM. THE ECMWF
TRIES TO MOVE A LOW ACROSS THE AREA TUESDAY NIGHT AND
WEDNESDAY, WHILE THE CANADIAN KEEPS THE LOW OVER THE
SOUTHEASTERN US BUT DOES PUSH MOISTURE AND PRECIPITATION OVER
THE AREA. IN CONTRAST, THE GFS KEEPS THE ENTIRE SYSTEM SOUTH OF
THE AREA. THIS IN TURN SETS UP MASSIVE DIFFERENCES IN THE MODELS
FOR THE END OF THE WEEK, LEADING TO VERY LOW CONFIDENCE IN ANY
PARTICULAR SOLUTION.
AVIATION /03Z SATURDAY THROUGH WEDNESDAY/
AS OF 645 PM FRIDAY...
AS CONDITIONS WORSEN FROM BORDERLINE MVFR TO MVFR OR LOW MVFR THE
TREND WILL CONTINUE INTO THE LATE MORNING AS IFR CIGS BECOME
DOMINATE. RAIN SHOULD BE LIGHT IN NATURE AND NOT CAUSE MUCH
HAVOC ON VIS RESTRICTIONS, MAYBE JUST SOME TEMPORARY MVFR UNDER
PROLONGED HEAVIER SHOWERS. SOUTHEASTERLY FLOW WILL TURN MORE
SOUTHWESTERLY BY SATURDAY AFTERNOON AND WINDS SHALL REMAIN MILD
AS FLOW WEAKENS. WITH FLOW WEAKENING NEAR BKW THERE COULD BE
SOME LLWS NEAR THE TERMINAL DURING AFTERNOON AND THIS WAS
MENTIONED IN THE TAF.
PRECIPITATION SHOULD FALL AS MOSTLY RAIN FOR THE SITES, HOWEVER
IT IS POSSIBLE FOR BKW TO SEE SOME FREEZING RAIN BEFORE SURFACE
TEMPERATURES MODERATE SLIGHTLY AFTER MIDNIGHT. ICE
ACCUMULATIONS SHOULD BE PATCHY AT BEST. EKN WILL CONTINUE TO
ENDURE SOME LIGHT SNOW WHICH MAY BRING VIS DOWN TO LOW MVFR
UNTIL MIDNIGHT WHEN TEMPERATURES MODERATE. SOME MORE RAIN MAY
SNEAK INTO THE PICTURE BY LATE MORNING ALTHOUGH BY EARLY
AFTERNOON A LULL WILL RESIDE UNTIL THE NEXT DISTURBANCE BRINGS
MORE INTO THE AREA LATE SATURDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR CIGS MAY VARY FROM TAFS.
FREEZING PRECIPITATION MAY VARY AT EKN/BKW DEPENDING ON HOW
FAST TEMPERATURES WARM UP.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 02/27/21
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H M H M H H H H
HTS CONSISTENCY L H H M H H M M H M H H
BKW CONSISTENCY H H H H M M H H H H H M
EKN CONSISTENCY H H M M L H H H H H M H
PKB CONSISTENCY M M H M H H H H H M H H
CKB CONSISTENCY H H H H H H M H H H M M
AFTER 00Z SUNDAY...
IFR POSSIBLE IN PERIODS OF RAIN SATURDAY NIGHT THROUGH EARLY
MONDAY.
RLX WATCHES/WARNINGS/ADVISORIES
WV...FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING
FOR WVZ005>008-013>020-024>034-039-040-515>526.
WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR WVZ516-518-
520-522>524-526.
OH...FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING
FOR OHZ086-087.
KY...FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING
FOR KYZ101>103-105.
VA...FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY MORNING
FOR VAZ003-004.
SYNOPSIS...RPY/CG
NEAR TERM...JZ/CG
SHORT TERM...TRM
LONG TERM...RPY
AVIATION...JZ
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