Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 270731
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
224 AM EST TUE JAN 27 2015

.SYNOPSIS...
COLD NORTHWEST FLOW TODAY AND TONIGHT. HIGH PRESSURE
WEDNESDAY. LOW PRESSURE THURSDAY. HIGH PRESSURE SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
MODELS CONTINUE TO SHOW SOME LOW LEVEL MOISTURE PERSISTING OVER MUCH
OF THE FORECAST AREA TODAY...WITH EMBEDDED DRY POCKETS MAKING THE
FORECAST ESPECIALLY TRICKY. LOW LEVEL COLD AIR COMBINED WITH THE
MOISTURE AND UPSLOPE WILL KEEP CHANCES FOR SNOW IN MANY
AREAS...ESPECIALLY THE NORTHERN MOUNTAINS OF WEST VIRGINIA. WITH
MESO NAM HAVING BETTER RESOLUTION THAN THE GFS IN THE LOW LEVELS
WHERE THE COLDER AIR IS LOCATED...OPTED TO STAY CLOSER TO THE MET
MOS FOR BOTH TEMPERATURES AND DEWPOINTS TODAY.

WITH WINDS BECOMING FAIRLY LIGHT IN SOUTHEAST OHIO AND KENTUCKY
TONIGHT AND CLOUDS CLEARING...WENT ON THE LOWER SIDE OF MOS GUIDANCE
THERE.

&&

.SHORT TERM /WEDNESDAY/...
NORTHWEST UPSLOPE FLOW...COLD AIR AND SUFFICIENT LOW-LEVEL MOISTURE
WILL RESULT IN A CONTINUING CHANCE OF ACCUMULATING SNOW...ESPECIALLY
ACROSS THE FAVORABLE NORTHERN MOUNTAINS AREAS...EARLY TUESDAY NIGHT.
HOWEVER...SURFACE HIGH WILL BUILDS IN AND SHUT OFF THE SNOW SHOWERS
BY SUNRISE ON WEDNESDAY.

THIS HIGH WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH WEDNESDAY
NIGHT...WHEN A FAST MOVING CLIPPER TYPE SYSTEM APPROACHES THE AREA
FROM THE WEST.

PRECIPITATION SHOULD OVERSPREAD THE REGION FROM THE WEST ON
THURSDAY...AS A WARM FRONT PUSHES NORTHEAST DURING THE DAY. A COLD
FRONT SHOULD THEN FOLLOW AND SHOULD BE LOCATED NEAR THE OHIO RIVER
BY LATE THURSDAY.

FOR TEMPS...GENERALLY WENT WITH A BLEND OF THE NAM/MET GUIDANCE
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.  USED HPC NUMBERS WITH SOME
TWEAKS FOR HIGHS ON THURSDAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
ACTIVE WEATHER PATTERN CONTINUES WITH ONE SYSTEM MOVING ACROSS
THURSDAY NIGHT AND ANOTHER STRONGER SYSTEM OVER THE WEEKEND. THE
FIRST SYSTEM WILL BE A WEAKER CLIPPER LIKE SYSTEM THAT COMES OVER
THE STILL HIGH AMPLITUDE UPPER RIDGE IN THE WEST AND ROLLS ACROSS
THE OHIO VALLEY. MODELS IN BASIC AGREEMENT ON THE TRACK AND SPEED
OF THE SURFACE LOW...WHICH GOES JUST NORTH OF OUR AREA AND PUSHES
A COLD FRONT RAPIDLY ACROSS THURSDAY NIGHT. THE TYPICAL WARM
SOUTHERLY FLOW AHEAD OF THIS FRONT WILL BRING LIGHT RAIN EARLY
THURSDAY NIGHT...FOLLOWED BY POST FRONTAL SNOW SHOWERS IN
SIGNIFICANT COLD ADVECTION...ESPECIALLY IN THE NORTHERN AND
CENTRAL MOUNTAINS WHERE UPSLOPE WILL KICK IN. HOWEVER...THE SPEED
OF THE SYSTEM...AND HIGH PRESSURE BUILDING LATER FRIDAY...WILL
LIMIT THE OVERALL SNOW ACCUMULATIONS. WE GENERALLY EXPECT LITTLE
ACCUMULATION IN THE LOW LANDS BY THE TIME SNOW TAPER OFF LATER
FRIDAY MORNING...AND ACCUMULATIONS IN THE NORTHERN MOUNTAINS MAY
BE A FEW INCHES BEFORE TAPERING OFF LATER FRIDAY AFTERNOON.
TEMPERATURES WILL BE BELOW NORMAL BEHIND THE FRONT...WITH
TEMPERATURES STRUGGLING TO REACH FREEZING FRIDAY AFTERNOON.

SATURDAY LOOKS TO BE THE IN BETWEEN DAY OF SYSTEMS WITH A RATHER
TRANQUIL BY COLD HIGH PRESSURE SYSTEM OVER OUR AREA...TEMPERATURES
REMAINING BELOW NORMAL.

THE NEXT SYSTEM TO AFFECT US SUNDAY AND MONDAY LOOKS TO BE A STRONG
AND WET SYSTEM AS A RATHER POTENT PACIFIC SYSTEM CRASHES THRU THE
WESTERN UPPER RIDGE. THE BIG QUESTION HERE IS WHETHER THIS SYSTEM
PHASES WITH THE NORTHERN STREAM BY THE TIME IT REACHES US. THIS IS
VERY MUCH IN QUESTION...AND WILL CONTINUE WITH A MORE DETACHED
SOUTHERN ROUTE PER OUR CURRENT FORECAST...WPC...AND MAJORITY OF
GUIDANCE. THUS...WILL CONTINUE TO GO WITH A SNOW SYSTEM EXCEPT
POSSIBLY OVER THE SOUTHERN PORTIONS. HOWEVER...IT SHOULD BE NOTED AT
THIS TIME FRAME...THERE IS STILL PLENTY OF TIME FOR MODEL CHANGES IN
HANDLING THE SYSTEM.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A NORTHWEST WIND FLOW WILL COMBINE WITH LOW LEVEL MOISTURE TO KEEP A
STRATUS DECK OVER PORTIONS OF THE AREA THROUGH TUESDAY NIGHT. THERE
WILL BE HOLES AND AREAS THAT CLEAR HOWEVER...MAKING FOR A RATHER
TRICKY FORECAST. IN ADDITION...SOME RESTRICTIONS IN UPSLOPE SNOW
SHOWERS ARE A POSSIBILITY...WITH THE BEST CHANCES IN THE NORTHERN
MOUNTAINS OF WV.

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

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIO: TIMING AND LOCATION OF CLEARING AREAS/HOLES IN THE
STRATUS COULD 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                                   TUE 01/27/15
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    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  L    L    L    L    L    L    L    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    L    L    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z WEDNESDAY...
IFR CONDITIONS POSSIBLE THURSDAY MORNING IN SNOW SWITCHING TO RAIN
LATER.

&&

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

&&

$$
SYNOPSIS...JSH/JMV
NEAR TERM...RPY
SHORT TERM...JSH
LONG TERM...JMV
AVIATION...RPY










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