Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 041112
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
612 AM EST Sun Dec 4 2016

.SYNOPSIS...
Weak upper trough crosses this afternoon and tonight. A low
pressure system crosses Monday night and Tuesday. Briefly milder
in its wake mid week, then much colder late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 420 AM Sunday...

Active weather pattern returns to the CWA. Isentropic lift kicks off
this morning with light precipitation forming mainly in far southern
and eastern zones, as moisture streams out of Gulf region towards
the CWA. Still could be a brief wintry mix at the onset this morning
in southwest VA zones, but this will quickly change over to rain as
waa takes hold. Most of the activity today will be confined to these
areas, before a shortwave trough moves through the Great Lakes
region later today and tonight, spreading moisture across the CWA.
Out ahead of this feature, southeasterly flow will take hold across
the CWA, with moisture lifting across mountain zones, with drier
conditions across much of the lowlands for most of the day. Due to
southeast upslope flow, mountainous counties will remain cool
compared to remainder of CWA. Forecast soundings suggest the
potential for a wintry mix, including periods of sleet and freezing
rain, this afternoon and evening across favored areas of Randolph
and Pocahontas counties in the se upslope flow. Elected to go ahead
and issue a winter weather advisory for these areas, starting this
afternoon, through Monday morning. Generally figuring only a few
hundredths of an inch of ice accumulation at this point.

As the aforementioned system moves east of the region late
tonight/early Monday, will likely see a transition over to drizzle
for many areas as mid and upper levels dry out.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
As of 420 AM Sunday...

System pulls out first thing Monday morning. Low level westerly
flow quickly takes out the CAD and, with a lack of cold air
arriving in the wake of this system, temperatures climb quickly
above freezing, and any lingering light precipitation Monday
morning should be of the liquid variety.

The next system, a closed upper level low over northwest Mexico
this morning that loiters around there today before lifting out
into TX tonight and Monday, opens up and dampens out as it lifts
through the Ohio Valley Tuesday. This causes rain to rapidly
overspread the area overnight Monday night, and then move through
the area on Tuesday.

With a stronger surface low pressure system compared with its
predecessor, a stronger CAD wedge develops as the system
approaches Monday night, and freezing rain is again possible on
the higher eastern slopes and ridge lines of Pocahontas and
Randolph counties. Warm advection should erode the CAD wedge on
Tuesday.

A bit of snow is possible over the higher terrain of the northern
WV mountains on west to northwest upslope flow in the wake of the
system Wednesday morning, but only slightly colder air moves in, as
weak high pressure of Pacific origin approaches on Wednesday.

Models continue to differ on weather the next cold front, a much
stronger one, arrives Wednesday night.

Temperatures close to guidance blends, which reflect a compromise
that leans toward the lower side when models diverge Wednesday
night.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 420 AM Sunday...

A strong cold front crosses the area sometime Thursday. Models
continue to differ on this, one factor being whether a wave forms
along the front and slows it down. Per WPC and coordination with
neighboring offices, the forecast continues to represent a
compromise that leans toward the faster and colder side. This
would have rain showers that mix with and change to snow showers
in the west and over the higher terrain Thursday, followed by a
transition to all snow showers as Thursday evening approaches.

The cold air takes charge Thursday night, and remains in firm
control into Saturday. This sets up the potential for frozen
precipitation as the next weather system approaches Saturday
night, which would then likely change to rain at least across
much of the lowlands on Sunday given a track west of the area, at
least initially.

Temperatures close to a guidance blend, except leaning toward the
lower side on Thursday.

&&

.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
As of 610 AM Sunday....

Clouds will gradually lower today, as a system approaches the
region. Precipitation will develop after 11Z Sunday, in southwest
VA and extreme southern West Virginia first, with a brief wintry
mix possible across southwest Virginia through 14Z, before
changing to rain. Brief MVFR vsbys possible with this
precipitation. In addition, a southeasterly flow will develop
today, with widespread MVFR cigs developing along the eastern
slopes of the higher terrain, particularly after 19Z, including at
site KBKW.

More widespread precipitation will arrive after 00Z, with
widespread MVFR, and local IFR conditions forming. Precipitation
will mainly be in the form of rain, except across parts of the
northern mountains of West Virginia, where a wintry mix of sleet
and freezing rain will exist, along with areas of IFR, and local
LIFR.

Generally Light surface winds, although winds will increase and
become gusty at times across the higher terrain particularly after
20Z, with gusts in the teen to lower 20 kts range.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Timing of precipitation and associated
restrictions may vary from forecast.

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               SUN 12/04/16
UTC 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
EST 1HRLY       05   06   07   08   09   10   11   12   13   14   15   16
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    L    L
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
PKB CONSISTENCY  H    M    M    M    H    H    H    H    H    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M

AFTER 12Z MONDAY...
IFR possible in low ceilings into Monday particularly across the
higher terrain. Additional IFR possible in rain and snow towards
mid week.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Winter Weather Advisory from 3 PM this afternoon to 6 AM EST
     Monday for WVZ523-524-526.
OH...None.
KY...None.
VA...None.

&&

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



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