Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 020231
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
931 PM EST SUN FEB 1 2015

.SYNOPSIS...
LOW PRESSURE ENTERING OHIO RIVER VALLEY...WHIPS COLD FRONT THROUGH
OVERNIGHT/EARLY MONDAY.  HIGH PRESSURE CROSSES TUESDAY.  NEXT COLD
FRONT CROSSES WEDNESDAY NIGHT.  HIGH PRESSURE CROSSES FRIDAY.

&&

.NEAR TERM /THROUGH MONDAY/...
930 PM UPDATE...NO MAJOR CHANGES NECESSARY.

PREVIOUS DISCUSSION FOLLOWS...

LIGHT PRECIP STILL HANGING ON IN NE CWA...BUT SHOULD BE MOVING OUT
SOON. HAVE CANCELLED THE WINTER WEATHER ADVISORY THAT WAS IN
EFFECT FOR PERRY AND MORGAN COUNTY. WITH RAIN EXPECTED THROUGH
MOST OF THE NIGHT...AND MOISTURE QUICKLY MOVING OUT ONCE SNOW
STARTS AGAIN...DO NOT HAVE ENOUGH ADDITIONAL SNOW FORECAST TO NEED
THE ADVISORY.

LOOKING INTO TONIGHT...PRECIP STILL A COUPLE HOURS AWAY FROM THE
SW. WILL ARRIVE THROUGH THE AFTERNOON AS RAIN. WITH LOW LEVEL
TEMPS WELL ABOVE FREEZING...EVEN 850MB TEMPS 3C-6C THROUGH
MIDNIGHT...SO ANTICIPATE RAIN THROUGH MUCH OF THE NIGHT. COLD AIR
ARRIVES IN THE WEST DURING THE PRE-DAWN HOURS. SO RAIN WILL CHANGE
TO SNOW FROM WEST TO EAST THROUGH THE MORNING. SNOW MAY NOT REACH
OHIO RIVER UNTIL AROUND 12Z...I-79 CORRIDOR AROUND 14Z...AND INTO
THE MOUNTAINS SHORTLY THERE AFTER. AS MID LEVEL TEMPS CONTINUE TO
PLUMMET...WITH 850MB TEMPS -12C TO -15C BY 18Z. THIS WILL LEAD TO
LIGHT FLUFFY SNOW THAT COULD ACCUMULATE WELL BY LATE MORNING INTO
THE AFTERNOON. CURRENTLY HAVE EVERYTHING BELOW ADVISORY
CRITERIA...BUT DOES NOT TAKE A LARGE STRETCH TO SEE THINGS GETTING
INTO THE 2 INCH RANGE FOR THE LOWLANDS OF WEST VIRGINIA SO WILL
INCLUDE IN HWO. WILL ALSO HAVE RATHER GUSTY WINDS AS THE COLD AIR
PLOWS IN. THIS WILL CAUSE REDUCED VISIBILITIES AS THE LIGHT FLUFFY
SNOW BLOWS AROUND. THIS WILL BE HITTING DURING MORNING COMMUTE
TIME FOR MUCH OF THE LOWLANDS.

HAVE NON-DIURNAL TEMPS BOTH TONIGHT AND MONDAY. TONIGHT...NOT
FALLING AS QUICKLY THROUGH 1-2 AM...AND THEN BEGINNING TO
ACCELERATE DOWNWARD. TEMPS WILL CONTINUE TO FALL THROUGH MONDAY.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MODELS NEARLY COME IN LINE BY THE START OF THE PERIOD WITH INTENSE
LOW PRESSURE JUST E OF CAPE CODE...AND HIGH PRESSURE OVER THE MID
MISSISSIPPI AND LOWER OHIO VALLEYS.  THE HIGH BUILDS INTO THE MIDDLE
OHIO VALLEY AND CENTRAL APPALACHIANS MON NT...CUTTING UP THE UPSLOPE
FLOW AND ASSOCIATED SNOW SHOWERS.  THINK MOISTURE IS DEEP ENOUGH FOR
MEASURABLE PRECIPITATION ONLY FOR THE FIRST COUPLE OF HOURS OF THE
NT.  HAVE UP TO AN ADDITIONAL FLUFFY HALF INCH IN THE NORTHERN
MOUNTAINS EARLY MON NT.

HIGH PRESSURE MOVES ACROSS TUE...YIELDING TO SW FLOW ON ITS BACK
SIDE TUE NT INTO WED.  HOWEVER...A COUPLE OF MID LEVEL S/W TROUGHS
PASS...ONE TUE AND ANOTHER TUE NT...EACH WITH ALTOCU COMING ACROSS.
BY TUE NT...PRECIPITATION COULD BE CLOSE BY TO THE N.  HAVE SCHC
GRADUALLY CREEPING ALONG THE NRN TIER TUE NT INTO WED...BEFORE YET
ANOTHER S/W TROUGH APPROACHES FROM THE W. THIS ONE IS PROGGED TO BE
MORE AMPLIFIED...WITH AN ATTENDANT SFC LOW DRAGGING A COLD FRONT
TOWARD THE AREA TOWARD THE END OF THE PERIOD.  THIS CARRIES AN
INCREASING CHANCE FOR PRECIPITATION ACROSS THE NW HALF OF THE FCST
AREA WHICH SHOULD TAKE MAINLY THE FORM OF RAIN...MAYBE EVEN MORE SO
THAN CURRENTLY CODED.

USED A CONSALL/MET BLEND FOR HOURLY TEMPERATURES MON NT IN COLD
ADVECTION THAT GRINDS TO A HALT.  AVERAGED IN A BIAS CORRECTED BLEND
FOR LOWS TUE NT...MAY EVENTUALLY NEED TO DEPICT A NON DIURNAL TREND
THEN.  BLENDED IN CONSALL TO ADJUST HIGHS...OVERALL NO MAJOR CHANGES
TO THE TEMPERATURE FCST...A LITTLE HIGHER ON HIGHS AHEAD OF THE
SYSTEM ON WED.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BROAD EASTERN MID/UPPER LEVEL TROF WITH FAST FLOW...AND FEW
OPPORTUNITIES TO ACCESS THE GULF OF MEXICO MOISTURE.

WEAK WARM AIR ADVECTION ONGOING TUESDAY NIGHT...WILL TRY TO BRING
SOME 20/30 POPS A BIT FASTER SOUTH BY DAWN WEDNESDAY INTO OUR
NORTHERN COUNTIES.

12Z GFS A BIT MORE AGGRESSIVE WITH THE MOISTURE  MOVING UP THE OHIO
VALLEY WEDNESDAY ALONG THAT FRONTAL BOUNDARY. ECMWF CERTAINLY NOT AS
MOIST. FOR NOW...WILL KEEP POPS IN CHANCE CATEGORY WITH FRONT
WEDNESDAY INTO WEDNESDAY NIGHT.

HAVE COLDER AIR BLOWING SOUTH AGAIN OVERNIGHT WEDNESDAY NIGHT INTO
THURSDAY.  WENT COLDER THAN OUR PREVIOUS FORECAST.

DRYING AGAIN THURSDAY NIGHT THRU FRIDAY NIGHT.

IN THE FAST FLOW...NEXT SYSTEM COULD ARRIVE BY LATE DAY 7.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
LOW PRESSURE WILL MOVE NORTHEAST THROUGH THE OHIO VALLEY TONIGHT.
WILL EXPECT A GRADUAL CHANGE OVER FROM RAIN...TO A WINTRY MIX THEN
SNOW AS THE NIGHT PROGRESSES...AND INTO THE DAY MONDAY. EXCEPT FOR
ACROSS THE NORTHERN MOUNTAINS...INCLUDING WEBSTER...RANDOLPH AND
POCAHONTAS COUNTIES...WHERE AREAS OF SNOW...FREEZING RAIN...AND
SLEET ARE EXPECTED GENERALLY 00Z THROUGH 07Z...BEFORE CHANGING TO
ALL RAIN. EXPECTING WIDESPREAD MVFR CONDITIONS TO DEVELOP IN
RAIN...PARTICULARLY AFTER 03-06Z.

RAIN WILL THEN GRADUALLY CHANGE TO -SN...ACROSS SOUTHEAST OHIO AND
NORTHEAST KENTUCKY 08-11Z...ACROSS WEST VA LOWLANDS...MOUNTAINS OF WV...AND
SOUTHWEST VA 08-13Z. EXPECT WIDESPREAD IFR AND LOCAL LIFR
CONDITIONS DURING THIS PERIOD.

SOME IMPROVEMENT TO MVFR ACROSS PARTS OF SOUTHEAST OHIO...EASTERN
KY...AND WV LOWLANDS AFTER 15Z...WITH GRADUAL IMPROVEMENT TO LOW
VFR AFTER 22Z. MVFR AND IFR CLINGING ACROSS THE HIGHER TERRAIN FOR
MOST IF NOT ALL OF TAF PERIOD.

IN ADDITION...GUSTY SSW WINDS WILL GRADUALLY SHIFT TO THE SW THEN
WEST TO NORTHWEST AFTER 09Z...WITH GUSTS OF UP TO 26 KTS ACROSS
THE LOWLANDS...AND UP TO 40 KTS POSSIBLE HIGHER TERRAIN.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIO: TIMING OF DROPS INTO MVFR AND IFR MAY VARY.
CONDITIONS MAY IMPROVE TO LOW VFR SLOWER THAN CURRENTLY FORECAST
ON MONDAY.

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                                                       MON 02/02/15
UTC 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
EST 1HRLY       21   22   23   00   01   02   03   04   05   06   07   08
CRW CONSISTENCY  M    M    H    H    H    H    H    L    H    H    M    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    M    H    H    H
BKW CONSISTENCY  M    M    H    H    H    H    L    L    M    M    M    H
EKN CONSISTENCY  M    M    M    M    M    H    H    H    M    M    M    M
PKB CONSISTENCY  L    L    L    L    M    M    M    M    M    H    H    H
CKB CONSISTENCY  M    H    H    H    H    H    L    L    M    L    L    H

AFTER 00Z TUESDAY...
IFR CONDITIONS IN SNOW SHOWERS MAY LINGER INTO MONDAY NIGHT IN AND
NEAR THE MOUNTAINS OF WV. IFR POSSIBLE IN LIGHT SNOW WEDNESDAY
NIGHT INTO THURSDAY.

&&

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

&&

$$
SYNOPSIS...KTB/TRM/MZ
NEAR TERM...MZ/SL
SHORT TERM...TRM
LONG TERM...KTB
AVIATION...SL







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