Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 162349
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
649 PM EST TUE DEC 16 2014

.SYNOPSIS...
IN WAKE OF COLD FRONT...ABUNDANT LOW LEVEL MOISTURE THROUGH THURSDAY
NIGHT.  HIGH PRESSURE FRIDAY. LOW PRESSURE APPROACHES FOR THE
WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AT 18Z FRONT APPROACHING CKB TO BKW LINE.  STRONG MID LEVEL
DISTURBANCE LOCATED NEAR DAY AT 18Z...HEADING EAST..TIMING IT
TO PASS THROUGH NORTH CNTRL WV ABOUT 00Z WEDNESDAY.

INTERESTING THAT HERE IN MID DECEMBER...WE CAN NOT GET A GOOD
TEMPERATURE DROP...EVEN IN THE  WAKE OF A COLD FRONT. WE KEPT
TEMPERATURE ABOVE FREEZING OVERNIGHT TONIGHT...EXCEPT IN ELEVATIONS
ABOVE 3000 FEET.

WITH THE LOW LEVEL FLOW MOSTLY WESTERLY...HARD TO FIGURE HOW LOW THE
CLOUDS GO FOR THE SOUTHERN MOUNTAINS...AND THUS...HOW HARD TO FIGURE
AMOUNT OF DRIZZLE LATE OVERNIGHT...BUT MORE LIKELY FURTHER NORTH.
ALONG WITH A MIXTURE OF LIGHT RAIN AND SNOW SHOWERS IN THE HIGH
ELEVATIONS OF THE CENTRAL MOUNTAINS...WILL INCLUDE THE POSSIBILITY OF
SOME FREEZING DRIZZLE...SINCE SATURATED MOISTURE DEPTH MOSTLY AOB 5
THSD FT MSL.  AREA IS VERY LIMITED FOR THAT FREEZING DRIZZLE.

COLDEST 850 MB AIR 12Z TO 15Z ON WEDNESDAY.  WILL HOLD ONTO OVERCAST
INTO AFTERNOON...WITH SOME CLEARING IN THE WESTERN COUNTIES. THE
TEMP TRACE ON WEDNESDAY MAY STILL GO DOWN A BIT 12Z TO 15Z THEN
TRY TO CREEP UP A FEW DEGREES DURING THE AFTERNOON.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
MODELS SHOWING SOME LOW LEVEL MOISTURE REMAINING WEDNESDAY
NIGHT INTO THURSDAY MORNING WITH COLD ADVECTION AND UPSLOPE
NORTHWEST FLOW. MOISTURE IS SHALLOW...BUT BELIEVE THAT SOME FLURRIES
ARE POSSIBLE IN THE NORTHERN AND CENTRAL MOUNTAINS.

A WEAK DISTURBANCE MOVES ACROSS ON THURSDAY. WITH DRY AIR IN THE LOW
LEVELS...NOT SURE THAT THE PRECIPITATION WILL MAKE IT TO THE GROUND.
WILL LEAVE DRY FOR NOW...BUT MAY NEED TO ADD SOME SMALL CHANCES IF
THE MODELS CONTINUE TO TREND WETTER WITH THIS DISTURBANCE.

SOME COLD AIR ADVECTION SETS BACK IN BEHIND THE DISTURBANCE THURSDAY
NIGHT. WITH LIGHT UPSLOPE FLOW CONTINUING AND SOME LOW LEVEL
MOISTURE...WILL ADD SOME FLURRIES IN THE NORTHERN AND CENTRAL WEST
VIRGINIA MOUNTAINS.

HIGH PRESSURE BUILDS IN FOR FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ACTIVE WEATHER IN THE LONG TERM PERIOD. PERIOD STARTS OUT WITH A
SPLIT UPPER FLOW PATTERN ACROSS THE U.S...WITH A LOW PRESSURE SYSTEM
IN THE SOUTHERN STREAM MOVING EAST ACROSS THE SOUTHEASTERN UNITED
STATES FRIDAY NIGHT INTO SATURDAY...WITH A SHORTWAVE TROUGH IN THE
NORTHERN STREAM PUSHING EAST ACROSS THE OHIO VALLEY...BRINGING A
REINFORCING SHOT OF COLD AIR INTO THE REGION. MODELS ARE STARTING TO
COME INTO BETTER AGREEMENT WITH THE TRACK OF THE LOW...BUT ECMWF IS
DEEPER...AND MORE PROGRESSIVE WITH NORTHERN STREAM SHORTWAVE...THUS
RESULTING IN A COLDER SOLUTION. DEPENDING ON WHICH SOLUN PANS
OUT...COULD SEE MORE OF A WINTRY MIX...AS WITH THE GFS SOLUN...OR A
MAINLY SNOW...WITH POSSIBLY BRIEF RAIN/SNOW MIX ACROSS
LOWLANDS...WITH THE ECMWF SOLUN. HAVE TRENDED THE FORECAST TOWARDS
HPC...WHICH TENDS TO FAVOR WARMER SOLUN. THUS...EXPECTING A WINTRY
MIX TO DEVELOP ACROSS THE AREA FRIDAY NIGHT/SATURDAY...BEFORE
TRANSITIONING TO MAINLY RAIN ACROSS THE LOWLANDS SATURDAY...THEN
BACK TO SNOW OR A MIX SATURDAY NIGHT. ITS POSSIBLE WINTER WEATHER
HEADLINES MAY BE NEEDED DURING THIS PERIOD.

HIGH PRESSURE WILL BUILD IN BEHIND THE SYSTEM FOR EARLY NEXT
WEEK...FOR A BRIEF BREAK IN THE PRECIPITATION...BEFORE ANOTHER
SYSTEM MOVES IN TOWARDS MID WEEK.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
GENERALLY...HAVE MEDIUM CONFIDENCE IN FORECAST THIS PERIOD. MVFR
CIGS THIS EVENING WILL LOWER TO IFR AS CAA CONTINUES WITH AREAS OF
DRIZZLE CONTINUING. CIG VALUES MAY DROP LOWER THAN FORECAST AND
THAT WHERE THE GREATEST UNCERTAINTY LIES.

THE OTHER REASON FOR MEDIUM CONFIDENCE...UNSURE HOW QUICKLY
CEILINGS IMPROVE DURING THE DAYLIGHT HOURS ON WEDNESDAY.

CIGS DROP TO 1 TO 2 THSD FT TONIGHT WITH VALUES AROUND 1 THSD FT
ACROSS MOUNTAIN COUNTIES. WIDESPREAD VSBY NEAR 5 MILES IN LIGHT
RAIN SHOWERS OR PATCHY DRIZZLE OVERNIGHT TONIGHT. VSBY AOB 3 MILES
ACROSS HIGH MOUNTAIN TERRAIN 04Z TO 14Z WEDNESDAY IN LIGHT MIXED
RAIN/SNOW SHOWERS OR DRIZZLE/FREEZING DRIZZLE.

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

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: CEILINGS MAY TAKE LONGER TO DETERIORATE IN
SOUTHERN WV MOUNTAINS TONIGHT. ALSO...THINNING CEILINGS MAY
LIFT...OR BREAK UP...SOONER IN THE OHIO VALLEY COUNTIES DURING THE
DAY ON WEDNESDAY.

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                                                                 WED
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    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    M    H    H
EKN CONSISTENCY  L    L    L    L    L    L    L    L    L    L    L    L
PKB CONSISTENCY  H    H    H    H    H    M    H    M    M    H    M    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 00Z THURSDAY...
HIGHER MOUNTAIN RIDGES MAY HAVE IFR IN CEILINGS WEDNESDAY NIGHT AND
EARLY THURSDAY AND AGAIN THURSDAY NIGHT INTO EARLY FRIDAY.

IFR POSSIBLE IN WINTRY MIX SATURDAY INTO SUNDAY.

&&

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

&&

$$
SYNOPSIS...KTB/RPY/SL
NEAR TERM...KTB
SHORT TERM...RPY
LONG TERM...SL
AVIATION...KTB/KMC




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