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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 011839
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
139 PM EST SUN MAR 1 2015

.SYNOPSIS...
COLD FRONT CROSSES TONIGHT. HIGH PRESSURE BRINGS DRIER WEATHER
MONDAY INTO MONDAY NIGHT.  ANOTHER WARM/COLD FRONT COMBO TUESDAY
INTO WEDNESDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
TEMPERATURES HAD RISEN ABOVE FREEZING THROUGHOUT MOST OF THE AREA AS
OF EARLY AFTERNOON.  THEREFORE THE ADVISORIES HAVE BEEN
DROPPED...WITH THE EXCEPTION ON POCAHONTAS COUNTY IN THE CAD.  THIS
EXPIRES AT 7 PM BY WHICH TIME THE LAST OF THE COLD AIR SHOULD
FINALLY BE ERADICATED.

THE WIDESPREAD PRECIPITATION WILL BE CUT OFF FOR THE MOST PART
TONIGHT AS A COLD FRONT CROSSES THE AREA.  MODELS DO SUGGEST ONE
LAST W-E DAGGER OF PRECIPITATION BEHIND THE FRONT TONIGHT...AS ONE
LAST TRAILING UPPER LEVEL S/W TROUGH MOVES THROUGH.  CONSIDERED
EXTENDING THE PERRY-MORGAN ADVISORY FOR THIS BUT THERE SHOULD NOT BE
A FREEZING RAIN THREAT AND ADDITIONAL SNOW AMOUNTS SHOULD BE AN INCH
OR LESS.

OTHERWISE UPSLOPE FLOW SUPPORTS SNOW SHOWERS IN THE MOUNTAINS
OVERNIGHT INTO MON WITH UP TO AN INCH OR SO THERE.  LOW LEVEL
MOISTURE WILL KEEP PLENTY OF CLOUDS AROUND MON...A MORNING CU
PROCESS IN THE MORNING...MIXING UP INTO A STRATOCU DECK THAT SHOULD
START TO BREAK UP IN THE AFTERNOON.  IT SHOULD CLEAR FURTHER AS HIGH
PRESSURE BUILDS INTO THE AREA AT THE END.

USED HRRR AND THEN NAM/MET FOR TEMPS...A BIT SHARPER BAROCLINIC ZONE
TONIGHT AND A BIT LOWER ON HIGHS MON COMPARED WITH PREVIOUS WITH
TEMPERATURES NOT RISING MUCH UNTIL AFTER 15Z.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
ATTENTION TURNS TO WHAT HAS BECOME A WELL ADVERTISED WET SYSTEM
SLATED FOR MID WEEK. LIKE HPC...STILL PREFER THE LESS PROGRESSIVE
SCENARIO GIVEN POSITIVE TILT TO UPPER TROF HANGING BACK...OWING TO
LESS PROGRESSION OF SFC FLOW AS THE FLOW ALOFT REMAINS PARALLEL TO
SFC FRONT. PRECIP WILL BREAK OUT ALONG DEVELOPING WARM FRONT
TUESDAY...WITH BEST CHANCES ACROSS SE OH. THERE MAY BE A VERY BRIEF
MIX AT THE ONSET...BUT THIS IS PRIMARILY A RAIN MAKER ON TUESDAY.
TRIED TO KEEP HIGH POPS CONFINED TO SE OH AND N WV AS REMAINDER OF
AREA REMAINS IN THE MORE SHOWERY WARM SECTOR. LLJ INCREASES TO NEAR
70 KTS TUESDAY NIGHT OUT OF SW WITH THE OVERALL FLOW TRYING TO
BECOME PARALLEL TO THE SFC COLD FRONT AS IT BEGINS TO SLOW DOWN
CONSIDERABLY ON APPROACH. COPIOUS AMOUNTS OF MOISTURE WILL BE POOLED
ALONG FRONTAL BOUNDARY...WITH PWATS SURGING TO NEAR 1.5 INCHES ON
IMPRESSIVE THETA E ADVECTION. THE FIRST AREA OF CONCERN WILL BE
ACROSS SE OH TUESDAY NIGHT...AND SLOW SHIFTING SE ON WEDNESDAY AS
THE FRONT SAGS SE. IT IS AT THIS POINT MODELS DIVERGE WITH GFS
CONTINUING TO BE ON THE PROGRESSIVE SIDE. THE NEW ECMWF IS NOT AS
PROGRESSIVE BUT DOES ENTRAIN MODIFIED ARCTIC AIR INTO THIS SYSTEM
COME WEDNESDAY NIGHT. AGAIN...STILL PREFER THE LESS PROGRESSIVE
SCENARIO ATTM...WHICH KEEPS THE RAIN GOING ALONG AND E OF THE OH
RIVER ON WEDNESDAY. KEPT THE HEAVY RAIN WORDING IN WX GRIDS. QPF
AMOUNTS LOOK TO AVG AROUND 2 INCHES AREAWIDE. WILL KEEP HWO WORDING
AS IS.

AS MENTIONED...THINGS GET TRICKY HEADING INTO WEDNESDAY NIGHT WITH
THE LESS PROGRESSIVE ECMWF WITH SECONDARY SURFACE WAVE FORMING ALONG
THE BOUNDARY AMID COLD AIR INTRUSION. THIS BRINGS A CONCERN THAT
STARTS WITH HEAVY RAIN AND FLOODING TO THE OTHER END OF THE SPECTRUM
WITH WINTRY WX. CONFIDENCE IS LOW REGARDING EXTENT OF ANY WINTRY WX
ON THE BACK SIDE OF THIS AND THE MAGNITUDE OF SUCH ATTM.

ON A SIDE NOTE...TEMPS WILL BE WARMING TO MORE SEASONAL LEVELS IN
THE WARM SECTOR WITH LOW TO MID 50S LOOKING LIKE A GOOD BET ON BY
TUESDAY AFTERNOON IN THE LOWLANDS AMID BREEZY S FLOW. THESE WARM
TEMPS HANG ON TUESDAY NIGHT FOR A RATHER MILD NIGHT FOR THIS TIME OF
YEAR. DEPENDING ON HOW THINGS PLAY OUT ON WEDNESDAY AND WEDNESDAY
NIGHT WILL DETERMINE JUST HOW RAPID A FALL OF TEMPS TO EXPECT BEHIND
THE FRONT.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
FRONTAL BOUNDARY WILL BE EAST OF THE AREA THURSDAY MORNING...WITH
COLDER AIR FILTERING INTO THE REGION...AND ANY LINGERING
PRECIPITATION CHANGING OVER TO SNOW. EXPECTING LIGHT ACCUMULATIONS
EARLY THURSDAY...PARTICULARLY ACROSS THE HIGHER TERRAIN COUNTIES.

HIGH PRESSURE WILL THEN BUILD IN BEHIND THE DEPARTING FRONT...FOR
CONTINUED COOL...BUT DRY CONDITIONS.
-- End Changed Discussion --

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
WIDESPREAD MVFR IN MAINLY RAIN ASSOCIATED WITH WARM ADVECTION S FLOW
OVER THE AREA...WITH TEMPERATURES ABOVE FREEZING AT ALL 6
TERMINALS.  VSBYS WILL IMPROVE OVERNIGHT TONIGHT AS DRIER AIR
ARRIVES IN THE WAKE OF A COLD FRONT THAT CUTS OFF THE WARM
ADVECTION.  THIS FRONT ROLLS THROUGH W TO E BETWEEN 3 AND 6Z. MVFR
OR WORSE VSBY WILL PERSIST IN THE MOUNTAINS OVERNIGHT AS RAIN
SHOWERS THERE CHANGE OVER TO SNOW SHOWERS BEHIND THE COLD FRONT.
CIGS TONIGHT WILL DROP TO CLOSE TO 1KFT...SO IFR CIGS ARE POSSIBLE.

MON WILL BRING IMPROVING CONDITIONS WITH MOUNTAIN SNOW SHOWERS ENDING
BY LATE MORNING...AND MORNING CU THAT WILL EVOLVE INTO AN AFTERNOON
STRATOCU DECK.  THESE CLOUD HEIGHTS WILL RISE...BUT MAY REMAIN BELOW
3KFT...BUT START TO BREAK UP IN THE LOWLANDS IN THE AFTERNOON...AS
HIGH PRESSURE BUILDS INTO THE AREA FROM THE NW.

LIGHT S SFC FLOW WILL BECOME LIGHT NW BEHIND THE FRONT OVERNIGHT.
MODERATE SW FLOW ALOFT THIS AFTERNOON INTO THIS EVENING...WILL
BECOME MODERATE W OVERNIGHT TONIGHT AND THEN MODERATE NW FOR MON.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: GUIDANCE SHOWS WIDESPREAD IFR TONIGHT.  THERE
IS THE CHANCE FOR THIS OCCURRING TONIGHT BEFORE THE COLD FRONT
ARRIVES.  THIS IS THE REASON FOR THE NUMEROUS INSTANCES OF L IN THE
TABLE BELOW.

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.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    L    L    L    L    L    L    L    L
HTS CONSISTENCY  H    H    M    M    L    L    L    L    L    L    L    L
BKW CONSISTENCY  H    H    H    M    L    L    L    L    L    L    L    L
EKN CONSISTENCY  H    H    H    H    L    L    L    L    L    L    L    L
PKB CONSISTENCY  H    H    L    L    L    L    L    L    L    L    L    L
CKB CONSISTENCY  H    H    L    L    L    L    L    L    L    L    L    L

AFTER 18Z MONDAY...
IFR POSSIBLE IN RAIN SHOWERS TUESDAY INTO WEDNESDAY...AND PERHAPS
SNOW AT THE END WEDNESDAY NIGHT.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ046.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/RPY/SL/30
NEAR TERM...TRM
SHORT TERM...30
LONG TERM...SL
AVIATION...TRM