Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 262343
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
643 PM EST THU FEB 26 2015

.SYNOPSIS...
COLDER AIR SQUEEZES OUT A FEW SNOW SHOWERS OVERNIGHT INTO EARLY
FRIDAY. DRY ARCTIC HIGH PRESSURE FRIDAY INTO SATURDAY.
CLIPPER LATE IN THE WEEKEND. ANOTHER LOW EARLY TO MID WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
DRIER AIR CONTINUES TO MOVE EAST IN WAKE OF EAST COAST STORM.  DRIER
DEW POINTS MOVING INTO THE MOUNTAINS 18Z TO 00Z. WILL STILL LEAVE A
POSSIBLE INCH OR SO OF SNOW ACCUMULATION IN OUR CENTRAL WV MOUNTAIN
COUNTIES OVERNIGHT AS THE AIR TURNS COLDER...AND BETTER CRYSTAL
GROWTH TEMPERATURES.

CERTAINLY THE COLD IS THE MAIN STORY THE NEXT 36 HOURS...OVER ANY
ADDITIONAL SNOW IN SNOW SHOWERS.

BROAD 850 MB THERMAL TROF ON FRIDAY AT MINUS 18 TO MINUS 19C...BUT
LATE FEBRUARY SUN SHOULD STILL HAVE AN EFFECT DURING THE AFTERNOON.
WILL TRY TO RECOVER TEMPERATURE A BIT IN THE LOWLANDS DURING THE
AFTERNOON.

MINIMUM TEMPERATURE TOUGH TO FIGURE FOR DAWN...SINCE HOW EXTENSIVE
THE CLOUDS BECOME...IN THE COLD AIR ADVECTION...IS ALSO IN QUESTION.
WILL TRY TO HOLD TEMPERATURES FROM RISING AFTER SUNSET..SAY BETWEEN
12Z TO 15Z.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
ARCTIC HIGH PRESSURE OVER THE MS...OH VALLEYS EXTENDS INTO WV FRIDAY
NIGHT INTO SATURDAY. MODELS IN AGREEMENT WITH H85 TEMPERATURES
AROUND MINUS 17C FRIDAY NIGHT...GRADUALLY WARMING UP TO MINUS 5C BY
00Z SUNDAY. MOSTLY CLEAR SKIES AND AREAS OF SNOW COVER WILL ALLOW
RADIATIONAL COOLING TO TAKE PLACE PROVIDING VERY COLD TEMPERATURES
FRIDAY NIGHT...GENERALLY IN THE SINGLE DIGITS LOWLANDS...RANGING TO
A DEGREE OR TWO BELOW ACROSS PORTIONS OF SOUTHEAST OH AND THE WV
NORTHEAST MOUNTAINS. PERIODS OF SUNSHINE ARE ANTICIPATED SATURDAY.

FLOW AT H50 BECOMES ZONAL SATURDAY. HOWEVER...A WEAK SHORT WAVE
RIDES EAST ALONG THE ZONAL FLOW CROSSING THE AREA SATURDAY INTO
SATURDAY NIGHT. MODELS ARE IN FAIR AGREEMENT IN THEIR QPF FIELDS
SPREADING PCPN FROM NORTHWEST TO SOUTHEAST...WITH THE FASTER NAM BY
LATE SATURDAY NIGHT ACROSS THE EXTREME NORTH AND SOUTHERN
SECTIONS...WHILE THE GFS AND ECMWF DELAY THE ONSET OF PCPN BY SUNDAY
THROUGH MONDAY. PER MODEL CONSENSUS...KEPT LIKELY AND CATEGORICAL
POPS CLOSER TO THE ECMWF AND GFS SOLUTIONS FOR SUNDAY.

FLOW AT H850 BECOMES SOUTH TO SOUTHWEST BRINGING MORE WARM ADVECTION
WITH TEMPS REACHING MINUS 5C TO 0C SUGGESTING PCPN COULD FALL IN THE
FORM OF LIQUID OR MIXED WITH SNOW OR SLEET.

WENT WITH THE BIAS CORRECTED CONSENSUS MOS AND ALL BLEND FOR
TEMPERATURES THROUGH THE PERIOD.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN IN THE LONG TERM...WITH LOTS OF UNCERTAINTY
IN THE DETAILS. FRONTAL BOUNDARY SOUTH OF THE CWA AT THE BEGINNING OF
THE PERIOD...WITH HIGH PRESSURE BUILDING IN BRIEFLY FROM THE NORTH.
HOWEVER...THIS WILL BE SHORT LIVED AS ANOTHER LOW WILL MOVE EAST OUT
OF THE PLAINS TOWARDS THE REGION. THERE COULD BE A BRIEF PERIOD OF
SLEET OR FREEZING RAIN EARLY TUESDAY MORNING AT THE ONSET OF
PRECIPITATION...BEFORE ENOUGH WARM AIR IS ABLE TO SCOUR OUT ANY COLD
AIR NEAR THE SURFACE. WITH A GOOD SOUTHWESTERLY FLOW
DEVELOPING...EXPECTING A CHANGE OVER TO RAIN BY TUESDAY
AFTERNOON...EVEN ACROSS THE MOUNTAINS.

AS MENTIONED IN PREVIOUS DISCUSSIONS...THERE WILL BE A GOOD TAP OF
GULF MOISTURE...AND THERE IS THE POTENTIAL FOR A SECONDARY LOW TO
RIDE UP OUT OF THE GULF INTO THE SOUTHEASTERN U.S. MID TO LATE
WEEK...BUT MODELS ARE NOT IN GOOD AGREEMENT IN THE PATH/MOISTURE
SPREAD ASSOCIATED WITH THIS FEATURE AT THIS TIME.

SO...POINT IS...WITH AT LEAST 1 FEATURE EXPECTED EARLY NEXT
WEEK...WITH THE POTENTIAL FOR HEAVY RAIN...AND A DECENT SNOW PACK IN
PLACE IN SOME LOCATIONS...PARTICULARLY SOME OF THE MOUNTAINOUS
LOCATIONS...WATER ISSUES ARE POSSIBLE. PARTICULARLY...IF THE
SECONDARY FEATURE WOULD HAPPEN TO DEVELOP...AND SPREAD A SECONDARY
ROUND OF PRECIPITATION ACROSS PARTS OF THE AREA LATE WEEK AFTER THE
INITIAL SHOT. HOWEVER...ANOTHER ISSUE WITH THE SECONDARY FEATURE IS
THAT BASED ON THE PATH...COULD EVEN SEE PERIODS OF SNOW...NOT JUST
RAIN. SO...LOTS OF UNCERTAINTY IN AMOUNT/RATE OF SNOW MELT...AND
EVEN IN PRECIPITATION AMOUNTS AND TYPES AT TIMES NEXT WEEK.

SO...IN A NUTSHELL...WILL GO AHEAD AND HIGHLIGHT THE RISK FOR
POTENTIAL FLOODING NEXT WEEK IN THE HWO...AS FEEL THERE IS AT LEAST
SOME RISK WITH THE FIRST FEATURE EARLY/MID WEEK.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
MVFR CEILINGS SHOULD REFORM 03Z TO 06Z ESPECIALLY IN WEST
VIRGINIA. SOME MVFR VSBY IN SCATTERED SNOW SHOWERS MOSTLY 04Z TO
14Z. MOSTLY VFR AFTER 14Z FRIDAY IN SCATTERED CLOUDS.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS:  LESS STRATOCUMULUS CEILINGS THAN EXPECTED ARE
POSSIBLE IN THE COLDER BUT DRIER ARCTIC AIR LATE TONIGHT INTO EARLY
FRIDAY. ALSO THE EXTENT IN WHICH THE SNOW SHOWERS IMPACT TAF SITES
MAY DIFFER...TOOK THE PESSIMISTIC APPROACH FOR THE MTN SITES.

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                                                                 FRI
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EST 1HRLY       19   20   21   22   23   00   01   02   03   04   05   06
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
BKW CONSISTENCY  L    L    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  M    M    M    M    M    M    M    M    H    H    H    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M
CKB CONSISTENCY  H    H    H    M    M    M    M    M    H    H    H    H

AFTER 00Z SATURDAY...
IFR POSSIBLE IN RAIN OR MIXED RAIN/SNOW SUNDAY INTO MONDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...KTB/ARJ/SL
NEAR TERM...KTB
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...JW









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