Area Forecast Discussion
Issued by NWS Charleston, WV-- Highlight Changed Discussion --
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FXUS61 KRLX 281705
Area Forecast Discussion
National Weather Service Charleston WV
1154 AM EST Mon Nov 28 2016
High pressure shifts east today with increasing southerly winds.
Periods of rain with several waves of low pressure Monday night
through mid week. Cooler high pressure to end the week.
.NEAR TERM /THROUGH TONIGHT/...
As of 630 AM Monday...
No significant change to forecast.
As of 450 AM Monday...
A big change from quite dry conditions today to very wet
conditions tonight. Models remain consistent on high pressure
with very dry air shifting eastward today. A frontal system will
approach from the west and move across most of the area tonight.
The pressure gradient increases over the area today between the
two systems, with increasing southerly winds that will become
gusty especially in the mountains. A wind advisory for our SW VA
counties is in effect later this afternoon into tonight, with an
expansion possible into the other mountain counties tonight. This
scenario will also bring a rapid increase of moisture originating
from the Gulf of Mexico later today, which will combine with the
front to bring widespread rain showers tonight.
For today, while we expect an enhanced fire danger, we do not expect
to meet red flag criteria. Models indicate that the parameters
needed for a red flag do not really come together, that is, while
the winds will be increasing so will the moisture, and fuel stick
moisture is marginal at best. So no fire headlines.
For tonight, good moist inflow and dynamics will bring the
widespread rain showers across the area from the west. No mention
of thunder with lack of deeper instability. However, there will
likely be a relative precip shadow just west of the mountains as
southerly winds do a component of downslope for awhile.
Nevertheless, we do expect a decent QPF with perhaps near a half
inch rainfall in this shadow zone to near one inch elsewhere.
Temperatures will be well above normal today despite all the mid-
high clouds. Tonight will also be quite mild with the clouds,
showers and southerly winds.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 400 AM Monday...
Operational and ensemble model guidance is in good agreement
through the short term period. Start the period off with warm
occlusion exiting the region mid morning Tuesday. A cold front
will remain to our west on Tuesday and we will be well within the
warm sector with deep southwesterly flow by midday. After we
clear out, we will see temperatures soar to near 70 degrees
across a large portion of the CWA by Tuesday afternoon except for
in the mountains.
The dry period will be short lived as pattern amplifies and
surface low pressure develops on frontal wave along the Gulf
Coast States and heads northeast along the front. This next system
has better dynamics than the wave coming through tonight into
Tuesday morning. We will be in close vicinity to a 150 knot jet
entrance region. With diffluence aloft, decent convergence with
the front at the surface and weak instability with near a couple
hundred joules of CAPE, it will be possible that the heavy rain
could have some embedded thunderstorms Wednesday afternoon. PWATs
are also going to be about 2 to 3 standard deviations above normal
for this time of year, but for the end of November that is only
about 1 to 1.1 inches. So there is potential for moderate to heavy
rain, and generally widespread 0.5 to 1 inch of QPF. However,
there will likely be some isolated spots that receive 1.5 inches
or more if some training were to occur. Even if amounts are a bit
higher than that the flash flood potential remains very low due to
the very dry conditions we have had of late. The creeks/streams
should be able to handle a decent amount of rainfall and if any
issues arise it will be an isolated incident.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 405 AM Monday...
Colder air pushes in on Thursday behind the cold front. Surface
high pressure builds in and this will keep us mostly dry, however
with northwesterly flow late Thursday night into the weekend I
can`t rule our the potential for upslope snow showers.
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --As of 1200 PM Monday...
VFR mid/high clouds can be expected this afternoon and
evening...with the exception of some southeast upslope clouds on the
eastern slopes of the mountains. Some showers may cause restrictions
this evening over southeast OH, northeast KY, and western WV. The
band of showers will push eastward overnight with some restrictions
possible with the band. The precipitation will move off to the east
Tuesday morning, allowing for improving conditions.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: High this afternoon and evening, then medium.
ALTERNATE SCENARIOS: Timing of restrictions overnight could 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.
UTC 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
EST 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
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 TUESDAY...
IFR possible in heavy rain midweek.
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VA...Wind Advisory from 4 PM this afternoon to 4 AM EST Tuesday for