Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 260550
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1212 AM EST MON JAN 26 2015

.SYNOPSIS...
LOW PRESSURE SYSTEM MOVES ACROSS THE AREA TONIGHT AND MONDAY. COLDER
AIR MOVES IN LATE MONDAY INTO TUESDAY.  HIGH PRESSURE WEDNESDAY.
LOW PRESSURE LATE THURSDAY.

&&

.NEAR TERM /THROUGH TODAY/...
CURRENT FORECAST REMAINS ON TRACK. NO CHANGES NECESSARY AT THIS
TIME.

PREVIOUS DISCUSSION BELOW...
QUITE A COMPLICATED FORECAST IN THE NEAR TERM PERIOD. FRONTAL
BOUNDARY ACROSS CENTRAL OHIO AT 18Z...WITH LIGHT PRECIPITATION
FORMING ALONG IT. MIXTURE OF PRECIPITATION JUST TO OUR
NORTH...WITH AREAS OF EITHER RAIN...OR A RAIN SNOW MIX...WITH SNOW
FARTHER TO THE NORTH ACROSS NORTHERN OHIO.

THE SURFACE LOW...CURRENTLY CENTERED ON CENTRAL KY...WILL MOVE EAST
ACROSS THE AREA TONIGHT...WITH PRECIPITATION CHANCES INCREASING AS
IT DOES SO. EXPECT BULK OF PRECIPITATION TO START OUT AS
RAIN...WITH A GRADUAL TRANSITION TO A RAIN SNOW MIX...THEN ALL
SNOW THROUGHOUT THE NIGHT AND INTO THE DAY MONDAY AS THE LOW
PUSHES EAST...AND UPPER TROUGH DIGS SOUTH ACROSS THE AREA...WITH
FALLING TEMPERATURES EXPECTED DURING THE DAY ON MONDAY. THERE
COULD BE A VERY BRIEF PERIOD OF SLEET DURING THE TRANSITION
PERIOD.

AT THIS POINT...FEEL CURRENT ADVISORY FOR JUST PERRY COUNTY SEEMS
REASONABLE. BASED ON FORECAST SOUNDINGS...WHICH WILL BE FAVORABLE
FOR SNOW...SURFACE TEMPERATURES FOR MUCH OF THE PERIOD WILL HOVER
AROUND OR ABOVE THE FREEZING MARK...THUS LIMITING THE SNOWFALL
POTENTIAL. SO ALTHOUGH IT MAY BE SNOWING...WE MAY HAVE A HARD TIME
ACCUMULATING ADVISORY CRITERIA SNOW. OUTSIDE OF PERRY
COUNTY...WHERE 1 TO 3 INCHES ARE CONFIGURED...GENERALLY HAVE AROUND
AN INCH ACROSS SURROUNDING SOUTHEAST OHIO COUNTIES...WITH 1 TO 4
ACROSS THE MOUNTAINS OF WEST VIRGINIA. PERRY COUNTY APPEARS TO STILL
BE THE MOST FAVORABLE LOWLAND COUNTY FOR ACCUMS AS SURFACE
TEMPERATURES SHOULD DROP EARLIER...AND STAY COLDER THERE LONGER.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
PRECIPITATION CHANCES WILL DECREASE FROM THE NORTHWEST MONDAY NIGHT
AS THE SYSTEM CONTINUES TO PULL AWAY FROM THE AREA. HOWEVER...
NORTHWEST UPSLOPE FLOW...COLD AIR AND SUFFICIENT LOW-LEVEL MOISTURE
SHOULD CONTINUE A CHANCE OF SNOW...MAINLY IN THE MOUNTAINS...INTO
EARLY WEDNESDAY.

APPEARS THE BEST CHANCES FOR SNOW ACCUMULATIONS IN THE MOUNTAINS
WILL BE ON TUESDAY WHEN DEEP NORTHWEST FLOW BECOMES BETTER
ESTABLISHED WHILE THE LOW-LEVEL MOISTURE IS STILL DEEP ENOUGH.

CURRENT THINKING IS THAT SEVERAL ADDITIONAL INCHES OF SNOW WILL BE
POSSIBLE ACROSS THE HIGHER ELEVATIONS...MAINLY MONDAY NIGHT AND
TUESDAY.

HIGH PRESSURE BUILDS IN WEDNESDAY...BRINGING THE SNOW CHANCES TO
AN END.

GUIDANCE TEMPS WERE COLDER FOR LOWS AND HIGHS THAN PREVIOUS
FORECAST.  WITH THIS IN MIND...HAVE TWEAKED THESE VALUES DOWN TO
REFLECT LATEST THINKING.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
PERIOD STARTS WITH HIGH PRESSURE OVERHEAD...THAT ALMOST IMMEDIATELY
GIVES WAY TO A LOW PRESSURE SYSTEM APPROACHING FROM THE W.  MODELS
ARE GENERALLY A BIT FASTER WITH THIS SYSTEM...SO PRECIPITATION COULD
REACH WRN PORTIONS OF THE FCST AREA AROUND DAWN THU.  THIS THEN
SPREADS E ACROSS THE AREA THU...FOLLOWED BY UPSLOPE PRECIPITATION IN
THE WAKE OF THE SYSTEM THU NT INTO FRI.

WITH THE LOW CENTER TRACKING OF THE AREA...ENOUGH WARM AIR SHOULD
ARRIVE FOR A MAINLY WET...NOT WHITE OR ICY...THU.  HOWEVER...MIXED
PRECIPITATION INCLUDING FREEZING RAIN COULD OCCUR AT THE BEGINNING
IF PRECIPITATION IS ABLE TO RUSH IN BEFORE SFC TEMPERATURES CLIMB
ABOVE FREEZING THU MORNING.  HOWEVER...GIVEN MOST OF THE AREA WILL
BE IN THE WARM SECTOR AHEAD OF A COLD FRONT THAT DOES NOT ARRIVE
UNTIL EVENING...MOST OF THE PRECIPITATION SHOULD OCCUR IN THE
AFTERNOON AND THEREFORE BE OF THE WET VARIETY.

COLDER AIR COMING IN BEHIND THE SYSTEM CHANGES THE RAIN TO SNOW
SHOWERS BUT THEN QUICKLY CUTS OFF THE PRECIPITATION FROM THE W AS
THE DRIER AIR MOVES IN.  UPSLOPE SNOW SHOWERS DIMINISH ON FRI...AS
HIGH PRESSURE BUILDS IN FROM THE W...CUTTING OFF THE MOISTURE AND
UPSLOPE FLOW.  THIS SHOULD LEAD TO GOOD RADIATIVE COOLING FRI NT.

ANOTHER SYSTEM AFFECTS THE AREA NEXT WEEKEND.  THE MODELS REMAIN
DIVERSE ON THE NATURE AND EVOLUTION OF THIS SYSTEM...BUT NONE
ADVERTISE ANYTHING MAJOR...AND ALL SHOW THAT THE OVERALL COLD THEME
IN A POSITIVE PNA CONTINUES.  THUS HAVE THE CHANCE FOR LIGHT SNOW
SHOWERS.

AT OR VERY CLOSE TO WPC VALUES FOR TEMPERATURES...THEY LOOKED LIKE A
VERY REASONABLE COMPROMISE BETWEEN THE INORDINATELY COLD AND DRY
ECMWFHIRES...AND THE GFS BASED GUIDANCE...WHICH SEEMED TOO HIGH
GIVEN ITS MASS FIELD SOLNS.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A LOW PRESSURE SYSTEM WILL BE MOVING ACROSS THE AREA OVERNIGHT. THIS
WILL CAUSE CEILINGS TO GRADUALLY COLLAPSE WITH SOME RESTRICTIONS IN
PRECIPITATION AS WELL. AS COLDER AIR MOVES IN BEHIND THE LOW ON
MONDAY...RAIN WILL TRANSITION OVER TO SNOW. A BAND OF IFR/LIFR SNOW
MAY POSSIBLY MOVE WEST TO EAST ACROSS THE REGION.

THE COLDER AIR WILL ALSO START OVER TURNING THE LOWER ATMOSPHERE
LATE MONDAY. THIS WILL LEAD TO A STRATUS DECK AND SNOW...WITH THE
LOWEST RESTRICTIONS IN THE MOUNTAINS. THE SNOW WILL CONTINUE MONDAY
NIGHT...WITH SOME IMPROVEMENT LATE IN THE NIGHT IN SOUTHERN
WV...VA...KY...AND OH.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIO: TIMING OF DETERIORATING CONDITIONS MAY VARY.

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 01/26/15
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EST 1HRLY       01   02   03   04   05   06   07   08   09   10   11   12
CRW CONSISTENCY  H    H    H    H    H    H    H    H    M    M    H    H
HTS CONSISTENCY  L    L    L    L    L    L    L    L    M    H    H    H
BKW CONSISTENCY  M    M    H    H    H    H    H    M    M    M    H    M
EKN CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  M    M    L    L    L    L    L    M    M    M    H    H
CKB CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z TUESDAY...
IFR POSSIBLE IN SNOW LATE MONDAY NIGHT INTO TUESDAY IN THE NORTHERN
AND CENTRAL WV MOUNTAINS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR OHZ066.
KY...NONE.
VA...NONE.

&&

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









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