Area Forecast Discussion
Issued by NWS Charleston, WV

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825
FXUS61 KRLX 230937
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
437 AM EST Sat Feb 23 2019

.SYNOPSIS...
A couple upper level impulses bring periods of rain today with
the best chance along and south of I-64. A cold front blows
through early Sunday, with strong, gusty winds behind it.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 100 AM Saturday...

Tried to sharpen up POP gradients throughout the period --
keying in on three impulses for the highest values. The first
has already crossed the southern forecast area and is pulling
away to the east so have POPs limited to the southeastern CWA
and on the decrease through around 09Z or so. The next impulse
is currently moving across TN, and should bring renewed rain
after sunrise. Again, keep the highest POPs along and south of
I-64, but have some uncertainty on the northern edge with this
impulse so leaked high chance POPs all the way across the
forecast area to account for this. This wave crosses by early
afternoon, so generally have POPs moving out to the east with a
lull from 18Z-21Z.

Attention then turns to an occluding front and another upper
level impulse which will lift across the forecast area
overnight. Have a fairly large area of 90-100 percent POPs
overnight with these features. Also include some rumbles of
thunder across the west near the occluding front and on the nose
of a low level jet. Flow off the surface does pick up, but is
still mostly warm advection, so any taller showers or storms
could pull down some of this, but not expecting anything to
significant with limited instability best area of shear lagging
behind.

Overall rainfall amounts for today and tonight range from
1.0-1.5" across the southern coal fields to 0.75-1.0" north of
Route 50. With the rainfall being divided up between multiple
impulses, creeks and streams will have some recovery time in the
lulls. This is still enough rainfall across the south, falling
on already soggy ground, to keep the flood watch going for
possible high water issues in typical poor drainage areas.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 435 AM Saturday...

A cold front blows through first thing Sunday morning. A well
mixed boundary layer in its wake, with the help of the late
winter strengthening sun, will result in efficient mixing of
45-60 kts h85 winds to the surface, especially during the
strongest low level cold advection, during the morning and early
afternoon hours on Sunday. Have peak gusts just over 50 kts over
the higher ridges of the northern WV mountains, and 40s
elsewhere in the high wind watch area, in and near the northern
WV mountains, as well as in the far northwest portion of the
forecast area.

In coordination with ILN, PBZ, LWX and RNK, have opted to leave
the high wind watch in effect as is for now. Portions of the
watch ara may only end up needing a high end advisory, and
advisories may be needed elsewhere in the forecast area,
especially near the watch area, and northwest portions of the
forecast area.

Very dry air builds in very quickly in the wake of the cold
front Sunday morning, with showers quickly becoming limited to
areas in and near the northern WV mountains by Sunday afternoon.
These rain showers will change to snow showers late Sunday as
colder low level air supports ice crystals in cloud, but with
minimal if any accumulation. The snow showers and strong winds
in the northern WV mountains gradually diminish Sunday night
into Monday morning.

High pressure builds in with welcome dry, and tranquil, weather
for Monday and Monday night.

Blended in the GFS and a bias consensus blend with central
guidance to depict the quick frontal passage Sunday morning.
Central guidance temperatures otherwise accepted, with only
seasonably chilly air to follow the cold front, as the
associated upper level low lifts quickly off to the east-
northeast.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 435 PM Saturday...

A dry cold front slips through almost unnoticed early Tuesday
morning into Tuesday afternoon, followed by a stronger high
pressure center. This continues the dry, and still only seasonably
chilly weather Tuesday through Tuesday night.

Model solutions become somewhat discombobulated from midweek on,
but center around the idea of a weak cold front crossing
Wednesday into Wednesday night, followed by weak systems
crossing as the front lingers nearby to the south of the area,
through the balance of the work week.

Central guidance temperatures accepted, near normal for late
winter, beneath nearly zonal upper level flow in the wake of the
upper level low exiting early in the week.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
As of 100 AM Saturday...

Several upper level impulses will bring areas of rain today into
tonight. The best chance today will be across southern sites,
with more area wide rainfall expected overnight. Could even get
a rumble of thunder across the west this evening. Expect MVFR
ceilings with each impulse, mainly across the south with the
first one, and then area wide overnight. Some IFR also possible
in the mountains. Kept visibilities mainly VFR for today, but if
any areas of moderate to heavy rain approach a TAF site,
amendments may be needed for a period of MVFR to IFR. Winds
will be out of the east to southeast through the period.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Ceilings and visibilities may vary in
heavier rain showers.

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 02/23/19
UTC 1HRLY       09   10   11   12   13   14   15   16   17   18   19   20
EST 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
CRW CONSISTENCY  H    H    H    M    L    H    L    L    H    H    H    H
HTS CONSISTENCY  H    H    M    H    H    H    H    H    L    H    H    L
BKW CONSISTENCY  M    M    H    H    H    H    H    H    H    M    H    M
EKN CONSISTENCY  H    H    H    H    H    H    H    M    H    L    H    M
PKB CONSISTENCY  H    H    H    H    H    H    M    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    H    M

AFTER 06Z SUNDAY...
IFR possible in rain into Sunday. Strong winds will impact all
sites Sunday, with speed shear possible with height.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...High Wind Watch from Sunday morning through Monday morning for
     WVZ030>032-039-040-521>523-525-526.
     Flood Watch through Sunday morning for WVZ005>007-013>015-
     024>027-033-034-515>520.
OH...Flood Watch through Sunday morning for OHZ083-086-087.
KY...Flood Watch through Sunday morning for KYZ101>103-105.
VA...Flood Watch through Sunday morning for VAZ003-004.

&&

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



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