Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 201100
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
600 AM EST Sat Jan 20 2018

.SYNOPSIS...
A warm front will pass later today, with some sprinkles or light
rain possible. This will also usher in milder temperatures for
the weekend. A strong cold front crosses late Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 600 AM Saturday...

Adjusted temperatures and sky cover for this morning based on
current obs and trends. Non-diurnal trend now in full swing --
it even appears that the more sheltered valleys have broken
through the inversion with temperatures on the increase.

As of 1250 AM Saturday...

Tricky temperatures again early this morning, as some areas have
decoupled and cooled quickly, while others remain mixed. In
general, have temperatures bottoming out in next couple hours
before starting to warm with incoming clouds and continued SW
flow. In a somewhat odd synoptic setup, our SW flow is actually
producing some mid level cold advection with closed upper low
near the Gulf Coast. So did not start warming higher elevations
until after sunrise.

Clouds should be on the increase today. Initially, expecting a
layer of cirrus which is already spreading in from the west. But
with the SW flow, the low to mid levels begin to saturate, with
a stratus deck forming/moving in from the SW. As moisture
continues to pump in, eventually we will see some
drizzle/sprinkles/light rain as a warm front lifts through.
Blended in ECMWF MOS for highs, which bumped up highs a degree
or two across the south.

The warm front departs to the north overnight, so cut back on
POPs. However still lingered slight chance to chance across the
north with GFS/ECMWF a bit slower than the NAM lifting the front
through. Went with a non-diurnal temperature trend tonight,
especially across the south after midnight.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 225 AM Saturday...

Evolution and timing are relatively consistent with the cold
front as it pushes into the middle Ohio Valley and exits the
central Appalachians. Warm frontal showers will push northward
of the region as the cyclone approaches with increasing low
level flows. As mentioned in the previous overnight forecast,
will see strong low level moisture transport, so will need to
watch the potential for brief moderate to heavy rain. Overall
amounts should not be all that high, but will need to watch the
hydro aspect of this with ice jams still present on some of the
area creeks, streams, and rivers. Temperatures ahead of the
front should reach the 60s across the lowlands Monday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 225 AM Saturday...

Extended forecast begins in the post frontal environment of the
Pacific frontal system with a period of lingering low level
moisture that will eventually yield snow showers in the higher
elevation of the mountains. Next wave of high pressure builds in
from the plains, progressive, and will bring return flow by the
end of the long term with above normal temperatures once again.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
As of 600 AM Saturday...

MVFR stratus in place across eastern forecast area. Eventually
this should build back across the lowlands as well. Could also
see some light drizzle or sprinkles late today into tonight as a
warm front lifts through. May get some IFR in this
stratus/drizzle tonight across the northern part of the forecast
area. Flow will continue out of the S to SW through the TAF
period.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing onset of MVFR cigs may vary. May
need to add IFR visibilities in drizzle or rain tonight.

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               SAT 01/20/18
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    M    M    M    L    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    M    L    L
BKW CONSISTENCY  H    L    H    H    M    M    H    H    M    M    L    L
EKN CONSISTENCY  H    H    H    H    H    M    M    M    M    M    L    L
PKB CONSISTENCY  H    H    H    H    H    H    H    H    M    M    L    L
CKB CONSISTENCY  H    H    H    H    L    L    H    H    M    M    L    L

AFTER 12Z SUNDAY...
IFR possible Monday/Monday night with rain.

&&

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

&&

$$
SYNOPSIS...MZ/26
NEAR TERM...MZ
SHORT TERM...26
LONG TERM...26
AVIATION...MZ


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