Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 071145
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
645 AM EST Wed Dec 7 2016

.SYNOPSIS...
Weak high pressure visits today. A cold front crosses early
Thursday morning, followed by much colder weather through
Saturday. Next system crosses Sunday night into Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 645 AM Wednesday...

Forecast on track.

As of 400 AM Wednesday...

WeaK high pressure starts to build into the area today, only to
get cut off at the pass, as low level west to southwest gradient
flow increases ahead of a cold front that approaches from the
west tonight.

Stratus/ stratocu beneath inversion was breaking up from the west,
although this process was obscured by a higher mid deck in the
mid and upper level southwest flow. While model soundings do not
strongly support clearing early this morning, it could make
farther progress at least into the low lands through daybreak.
After sunup, the morning cu effect will likely cause the clouds to
fill back in for a time, before mixing and the arrival of drier
air bring clearing this afternoon.

Higher clouds will lower and thicken tonight, as the cold front and
associated upper level short wave trough approach. In coordination
with neighbors, opted for a dry forecast tonight, given little
inflow and marginal moisture ahead of the front, along with weak
and transient forcing. Forecast does still reflect the slight
chance for snowflakes reaching the ground across higher terrain
from south to north toward dawn Thursday, from a dampening flat
wave.

Temperatures and dew points slightly higher this package from a
blend of near term sources, reflecting a slow push of only
slightly chillier and drier air in the wake of the weak cold
front that crossed on Tuesday night.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
As of 400 AM Wednesday...

Colder air will infiltrate into the region on Thursday as an upper
trough deepens across the area. Temperatures will remain either
steady, or gradually fall as the day progresses on Thursday, with
light snow showers developing later in the day Thursday and Thursday
night, mainly across the higher terrain counties, with flurries
elsewhere. Friday looks to be continued cold, along with additional
light snow showers in favored upslope regions as a more favorable
northwesterly flow takes hold. Still looking at light
accumulations,Medium into Wednesday morning, then generally an
inch or two across the higher terrain, with little to no
accumulations elsewhere. Snow showers will taper off later in the
day Friday and Friday night, as flow becomes less favorable, and
weak ridging takes hold over the weekend.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
As of 400 AM Wednesday...

Milder air to take hold over the weekend as weak upper ridging
builds in response to approaching sw trough/low pressure system,
which will spread light rain and snow showers back into the region
by late Sunday.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
As of 645 AM Wednesday...

Morning stratocu will go MVFR at times this morning, before
mixing out this afternoon, as weak high pressure briefly builds
into the area.

As the next cold front approaches from the west tonight, mid
level clouds from the associated upper level short wave trough
will overspread the area. This should be enough to keep fog from
forming. MVFR to IFR stratocu may form in the mountains toward
12Z Thursday.

Light west surface flow will diminish today, and be calm to light
and variable tonight. Flow aloft will be light to moderate west to
northwest.

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

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: Timing and occurrence of MVFR morning cu 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               WED 12/07/16
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    L    H    H    H    M    M
HTS CONSISTENCY  H    H    H    H    M    M    M    M    M    H    M    M
BKW CONSISTENCY  H    H    H    H    M    M    M    M    M    H    M    M
EKN CONSISTENCY  M    M    M    M    M    L    L    M    M    M    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    L    M    H    M    M

AFTER 12Z THURSDAY...
IFR in possible snow showers Thursday through Thursday night in
the mountains,

&&

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

&&

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


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