Area Forecast Discussion
Issued by NWS Charleston, WV

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717
FXUS61 KRLX 182000
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
300 PM EST Thu Jan 18 2018

.SYNOPSIS...
With high pressure passing south of the area, a southwest flow
will bring milder air through the weekend, with a warm front
passing Saturday. A cold front crosses late Monday.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 130 PM Thursday...

Broad sfc high pressure centered roughly over the lower MS River
will have a ridge, extending northeast across TN, KY and WV
through Friday. The high pressure center is expected to pass
well south of the area through the weekend.

Despite of clear skies expected, models show warm advection
under southwest to west winds. H850 temperatures will increase
just 2C by Friday from minus 2C this afternoon. Lows generally
in the teens, compared with the widepsread single digits of
early this morning, reflect the ongoing retreat of the arctic
air.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 240 PM Thursday...

Warm air advection continues with surface ridging into the area
to start the weekend. Gradual warming is expected through the
weekend ahead of the next storm system. High clouds start
streaming in later Saturday, with enough sunshine during the
day, especially toward the east, to warm us nicely into th 40`s
and 50`s.

A warm frontal boundary lifts across the region Sunday with some
modest over-riding flow. Overall not expecting a heavy rain
threat with this - expect mostly cloudy temperatures and a
continuation of the warming trend light rain showers. Depending
on timing, i.e. if the warm front lifts before diurnal heating
takes over, there could be a wintery mix in the mountains upon
precip onset.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 345 PM Thursday...

The cold front associated with the aforementioned system
skirting across the region moves through Monday into Monday
night according to latest model guidance. Expect good moisture
with PW around an inch or so, far above the climatological norm.
Luckily, this is a progressive system so not expected widespread
water issues at this time in spite of heavy rain potential. Will
have to keep an eye on rivers for ice jams, however.

Expect a Tuesday morning changeover to a wintery mix and snow,
expecially across higher terrain. Models at this time don`t show
great potential for cold air advection/upslope showers for very
long behind the front, but long range models are notoriously
poor in modeling these things - so have added in low PoPs
Tuesday especially across the north.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
As of 1245 PM Thursday...

CAVU through the period.

High pressure builds overhead to provide clear skies through the
period. The GFS and NAM show H850 west southwest winds around 40
knots around 2000 feet.  The NAM and RAP13 models suggest
Boundary layered winds of 20 to 30 knots overnight. Expecting
EKN site to decouple overnight to produce light to calm winds.
These conditions could produce low level wind shear at EKN
overnight and was included in TAFEKN starting at 05Z.

For the rest of the sites, light to gentle flow with occasional
gusty winds will reduce the threat for LLWS at other sites.

Light southwest surface flow, west to northwest on the ridges,
will strengthen and become a bit gusty this afternoon and
evening, before becoming light again tonight.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...

FORECAST CONFIDENCE: Medium to high.

ALTERNATE SCENARIOS: Timing of low level wind shear may vary.
Low level wind shear could materialize at other sites if the
lower atmosphere decouples.

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.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M

AFTER 18Z FRIDAY...
None.

&&

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

&&

$$
SYNOPSIS...ARJ/SL
NEAR TERM...ARJ
SHORT TERM...SL/MC
LONG TERM...MC
AVIATION...ARJ



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