Area Forecast Discussion
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FXUS61 KRLX 251852
Area Forecast Discussion
National Weather Service Charleston WV
252 PM EDT SUN SEP 25 2016
High pressure shifts east tonight. A cold front will cross Monday
with showers and thunderstorms. More autumn like temperatures
arrive for the remainder of the week.
.NEAR TERM /THROUGH MONDAY/...
As of 230 PM Sunday...
Models are in good agreement with a cold front moving rapidly
eastward across the area Monday. The front will reach the Ohio
River by early afternoon and in the mountains by evening. Even
with the speed of the system, models have a combination of decent
dynamics and pooling of moisture to near 2 inches along the
front. Thus, a band of showers and thunderstorms is expected to
accompany the front. However, QPF amounts will only be on the
order of a quarter to half an inch, thanks to the speed of the
system. SPC continues to outline a marginal risk of severe
weather, and will continue this in the Hazardous weather product.
Models also have a prefrontal band of convection forming Monday
afternoon along and east of the I79 corridor. Not too certain
about an organized area of convection there, so will go with
scattered convection there in the moist and unstable air; ahead
of the frontal band of convection. Convection will then ramp down
fairly quickly in the west behind the front by end of
period...with even some sunshine by later afternoon. Milder
tonight with increased moisture and southerly winds picking up
late, especially in the west. Highs Monday will still reach into
the 80s ahead of the front.
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 430 AM Sunday...
Strong cold front will move through the region on Monday...exiting
to the east Monday night. Showers and thunderstorms...will develop
across the area on Monday...particularly across WV and southwest VA
based on frontal timing. There is the possibility that a few storms
could be strong to severe on Monday...as deep layer west-
southwesterly winds increase to 40+kts. SPC has placed much of WV
and SW VA counties in a marginal risk for Monday. Have added wording
to the HWO to mention the strong-dmg wind threat for Monday.
Frontal boundary will be to the east of the CWA Monday night...with
gradual clearing taking place behind the front. Remainder of the
short term period looks to be cool...as upper low/trough deepens
across the eastern U.S. There could be periods of cloud or
showers...particularly across the north at times before the low
finally moves off the coast by late week...but much of the time
should remain dry.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 340 PM Friday...
While the operational models are at least consistent with a stout
upper low bringing a cold front through in the short term portion
of the forecast, the evolution of the upper low beyond that in the
extended is where forecast spread comes into play. The ECMWF
continues to bring the upper low south into the central
Appalachians, with it oscillating around that general area
through the end of the week. The GFS brings a similar track to an
extent...but eventually has it become an open wave and exiting
our area by Friday. This makes the grids challenging because of a
GFS specific trough axis dropping in and creating more defined
areas of potential precipitation while the ECMWF will be more
involved with less specific forcing details. Crossing fingers for
increased model run consistency in the coming days to sharpen up
this part of the forecast. Will keep the cooler trend going
through the period regardless with low end POPs.
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
18z Sunday thru 18Z Monday...
Weak high pressure this afternoon and tonight will shift east by
Monday morning, followed a cold front moving east across the area
A VFR mostly clear afternoon on tap for the lowlands and west
facing slopes of the WV and southwest VA mountains. On east facing
slopes of the mountains, look for SCT-BKN stratocu 2500-3500 feet
AGL this afternoon which will affect BKW. Light and variable
winds this afternoon, except light easterly winds on east facing
Tonight will feature a similar night to last night. Near calm
winds in most of the lowlands, with just an increase in mid to
high clouds late tonight, will result in generally MVFR to locally
IFR river valley fog after 06z, affecting mainly CRW EKN. Winds
will stir just enough to keep fog out of PKB and HTS. Light
southeasterly winds in mountains will bring MVFR/IFR ceilings back
to mainly east facing slopes of the mountains including BKW after
After 12z, look for rapid dissipation of fog and mountain stratus
as southerly winds increase ahead of the cold front. With moisture
and instability increasing, there may be a pop up shower or storm
anywhere during the afternoon ahead of the front. There will be a
band of showers and thunderstorms, with generally MVFR to locally
IFR conditions, with the cold front as it moves across the area.
Look for the front to reach the Ohio river by 18Z and the
mountains by 00Z. Southerly winds 5 to 10 KTS ahead of the front,
turning westerly 8 to 12 kts behind the front.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE: Medium
ALTERNATE SCENARIOS: Timing and height of fog and stratus
reformation tonight may vary. Timing of band of convection with
the front Monday may be a bit faster than forecast.
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
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
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 M H H H H H H M M M M L
EKN CONSISTENCY H H H H H H H H H M M L
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 MONDAY...
Low stratus possible over the mountains Monday night. Morning
valley fog possible Tuesday through Thursday mornings.