Scientific Forecaster Discussion
fxus61 krlx 200132
Area forecast discussion
National Weather Service Charleston WV
932 PM EDT Thu Apr 19 2018
high pressure builds from the northwest through the weekend.
Next system arrives Monday night.
Near term /through Friday/...
as of 930 PM Thursday...
Sent a quick update to put an end to the light snow showers over
the northeast mountains overnight. Still expecting freeze
conditions under calm flow and clear skies overnight into Friday
As of 530 PM Thursday...
Refreshed hourly temps and dewpoints up to 12 hours. Cancelled
Wind Advisory for the higher elevations. Rest of forecast
As of 130 PM Thursday...
Gusty winds and rain/wintry mix/snow showers continue this
afternoon under cold air advection behind a fast-moving cold front and upper
trough. A Wind Advisory is currently posted across the mountain
zones to cover stronger winds in higher elevations. A wintry
mix ("white rain") has been reported in heavier showers across
The Lowlands, and a transition to snow showers has already taken
place across higher elevations at this time.
Shower activity across The Lowlands is gradually tapering off
from northwest to southeast with the passage of a 500 mb shortwave today,
tapering entirely by Sundown. Northwest flow and lakes Huron/Erie
moisture plumes keep upslope snow showers present in the
mountains through early Friday morning with hires models
indicating a boost of shower activity between roughly 00-06z in
the north/central mountains. Accumulations will be generally
relegated to above 2500 ft, up to 1-3" are possible above 3500
The surface pressure gradient relaxes behind the aforementioned
500 mb shortwave this evening, and gradually decreases winds
through tonight, which may lead to an early expiration of the
Wind Advisory. Winds will be generally out of the NW, turning
Low level moisture hangs around with widespread cloud cover for
the rest of today. Then, high pressure builds tonight to clear
and dry much of The Lowlands. Calming winds and clearing skies
indicate good potential for radiational cooling - this, continued
caa, and dew points dropping into the 20's justify the
currently posted freeze warning posted for all of our zones
currently in the growing season including western WV, southeast OH, and
NE Kentucky. Mostly clear conditions allow for a warm Friday in spite
of cold air advection with lowlands highs in the upper 50's, corresponding
with minimum rh's in the upper 20's percent.
Short term /Friday night through Sunday night/...
as of 330 PM Thursday...
The region becomes encompassed by surface high pressure this
weekend, helping temperatures to rebound closer to seasonable
levels for this time of year. Clear skies will trigger efficient
radiational cooling overnight Friday, which may pose a need for
frost advisories across The Lowlands Saturday morning. As of the
latest forecast, Sunday morning will feature slightly warmer
temperatures that would keep the need for an advisory at Bay.
Long term /Monday through Thursday/...
as of 330 PM Thursday...
High pressure migrates northeastward in response to an upper
level disturbance making its way into the region from the
Central Plains. Next shot at seeing more of an active weather
pattern returns Monday night into Tuesday as the low meanders
over the lower Ohio Valley and becomes ingested by a stronger
system moving down from Canada, which will ultimately push the
next cold front through the area around midweek. Chose to go
with a model blend for the end of the period due to
discrepancies with models that far out.
Aviation /01z Friday through Tuesday/...
as of 740 PM Thursday...
Sfc weather charts show pressure gradient loosen up, decreasing
northerly gusty winds to northerly at 10 knots or less. Expect
these winds to continue to subside towards 04z when most places
are expected to decouple overnight and experience light to calm
flow under widespread VFR conditions. The exception could be at
and nearby bkw that an MVFR ceiling could develop overnight
under northerly flow. However, low level moisture might not be
present as dewpoints are in the 20s over the central mountains
preventing this deck to form.
Boundary layer winds subside from 15 knots to 10 knots or less
after 06-09z, allowing radiational cooling and corresponding
drop in temperatures. Despite of ideal conditions for dense fog
development, temperatures will drop into the 20s to produce
frost or freeze instead.
Widespread VFR conditions expected Friday as a high pressure
builds from the northwest.
Forecast confidence and alternate scenarios through 00z Saturday...
Forecast confidence: medium.
Alternate scenarios: IFR dense fog could develop along river
Experimental table of flight category objectively shows consistency
of weather forecast office 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 Friday 04/20/18
UTC 1hrly 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1hrly 20 21 22 23 00 01 02 03 04 05 06 07
crw consistency h h h h h h h h h h h M
heights 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 00z Saturday...
no widespread IFR conditions expected.
WV...freeze warning from 2 am to 10 am EDT Friday for wvz005>011-
Ohio...freeze warning from 2 am to 10 am EDT Friday for ohz066-067-
Kentucky...freeze warning from 2 am to 10 am EDT Friday for kyz101>103-