Area Forecast Discussion
Issued by NWS Charleston, WV-- Highlight Changed Discussion --
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FXUS61 KRLX 221854
Area Forecast Discussion
National Weather Service Charleston WV
254 PM EDT Sat Apr 22 2017
Upper level disturbance passes to the south, but inverted trough
keep rain in play through the rest of the weekend. High pressure
early next week. Next system late Thursday.
.NEAR TERM /THROUGH TONIGHT/...
As of 1145 AM Saturday...
Looks to be the eastward moving short wave over western parts
of the area at time will be the main player this afternoon. Hi
res models and radar picking up on this and indicate a break in
the widespread precip behind this feature from west to east.
However, with the frontal boundary hanging just south of the
area, will maintain higher pops in the south behind this feature
this afternoon. Any thunder will be confined to the far south
this afternoon closer to the frontal boundary. Otherwise, rain
will be winding down from at least the I64 corridor northward as
both the short wave exits and drier air filters down from the
north into these area this afternoon. Will continue the
current Flash Flood watch for the southern mountains with
continued higher pops.
As of 430 AM Saturday...
Wet weather in the near term period. Initial wave moves through this
morning, generally exiting the area by 10Z. Generally light
precipitation is associated with this initial wave. However, this
will be followed by another wave, with a band of heavy
precipitation, moving into the CWA around 15Z, before exiting later
this afternoon and evening. Models are in decent agreement
concerning the timing and location of axis of heavier precipitation
this afternoon with this wave, currently visible on radar across
southeast MO and western KY, and creating flooding concerns across
aforementioned areas this morning.
At this point, should be a brief break later this evening after the
second wave exits, but pops will increase again towards the end of
the period, particularly across southern zones, as low pressure
system moves east along stalled frontal boundary just south of CWA
towards our region, spreading more precipitation back into the area.
Could see the possibility of the FFA being expanded across eastern
zones in the future, but for now, there is still a bit of
uncertainty as to where the axis of heavier precipitation will set
up. Regardless, it looks like after the second wave passes today,
there will be a stark difference between northern zones i.e.
southeast Ohio and adjacent counties, and southern zones, which will
remain overcast and in higher moisture content air.
For now, with the location of the frontal boundary, and higher
confidence in heavier precipitation, have elected to issue a flash
flood watch across southwest VA and McDowell and Wyoming counties,
with the possibility it will need to be expanded in future
updates.Area of showers incoming from the south. Reworked POPs
to better reflect timing on these as they head NE.
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
As of 245 PM Saturday...
As the stacked low pressure system creeps towards the southeast
coast, inverted troughs aloft and at the surface will prevent a
quick exit to the showers through the Monday evening time frame.
The system will travel up the coast, lending its influence both
in terms of the non dry forecast and considerably cooler
temperatures on the eastern slopes of the mountains for Monday
and Tuesday, comparatively to the lowlands on the other side.
Will take some time to eliminate the mid level moisture from the
lows to the east, so have a mainly cloudy forecast in place for
the short term.
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 245 PM Saturday...
After warming through recovering thicknesses and 850mb
temperatures through mid week, long range operational models
still having trouble with the next system, which has now become
more of a Thursday entity. Two weak upper level waves will merge
to the northwest over the western Great Lakes, and continue a
track northeastward into northern Ontario, but a frontal system
will be poised to push through the Ohio Valley. However, with
the main energy well away from our CWA, the frontal system will
likely shear out, and the low POP solution into Thursday night
is likely to fluctuate in coming runs, but stay on the low end.
Baroclinic zone sets up into the weekend, so the higher
temperature forecast for the end of the week that came out
yesterday has come down a few degrees back to lowland low 80s.
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
As of 200 PM Saturday...
Improving conditions spreading south and east this afternoon and
tonight as upper disturbance shifts eastward across the area,
allowing drier air to filter in from the north. MVFR/IFR in
widespread rain and an isolated thunderstorm ahead of the upper
disturbance this afternoon, particularly across southern and
eastern West Virginia and southwest Virginia. Improvement to VFR
ceilings AOA 4000 feet by 00Z across southeast Ohio and
northwest WV, including PKB, behind the disturbance. Northerly
winds 8 to 13 MPH.
VFR ceilings works slowly south and east 00Z-03Z into central
WV by 06Z, reaching CKB by 02Z, but remaining just north of a
HTS- CRW-EKN line for the remainder of the night. MVFR ceilings
continue south of this line; except IFR in the southern
mountains, including BKW, where a continued rain threat exists
with frontal boundary stalled just to the south. Winds becoming
easterly at 5 to 10 MPH.
For Sunday, an upper low tracks to the south and then east of
the area, spreading rain back to the north and east. However,
most of the rain will be in the mountains. Winds southeast 5 to
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: Low to medium.
ALTERNATE SCENARIOS: Improving conditions may be faster and
farther south later this afternoon and tonight over the
northwestern half of WV, southeast Oh and northeast KY.
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 M M L L L M M M M M M L
HTS CONSISTENCY M M M M M M M M M M M L
BKW CONSISTENCY M L M M M L L L L L L L
EKN CONSISTENCY L M M L L L L L M M M L
PKB CONSISTENCY M M M M H H H H H H H M
CKB CONSISTENCY H M M M M M M M H H H M
AFTER 18Z SUNDAY...
IFR possible Sunday into Monday with another wave of low
WV...Flash Flood Watch through Sunday evening for WVZ033-034.
VA...Flash Flood Watch through Sunday evening for VAZ003-004.