Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 232022
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
322 PM EST Fri Feb 23 2018

.SYNOPSIS...
Nearly stationary front meanders about the area into Sunday, as
surface waves pass. Areas of significant rainfall possible into
the weekend. The front finally charges through on Sunday.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 250 PM Friday...

The front that has been oscillating about the area the past few
days, surged northward, as a warm front, today. In the warm
unstable air, quick-standing convection has fired up, with brief
heavy downpours and gusty winds, taking advantage of 45 kts deep
layer bulk shear, and nearly a kj/kg CAPE.

The convective nature of the precipitation should wane this
evening. However, the front sags southward tonight, ahead of
several waves that will moves northeastward across the area
tonight through Saturday. These frontogenetic waves increase
low level convergence along the front overnight tonight, the
front and associated convergence then moving back north
Saturday, This will bring increasing area coverage of rain,
which could be heavy because of elevated convection in strong
moisture transport that increases PW values toward 1.25 inches,
near the climatological max.

Convection may become closer to surface based Saturday, south
of the front, with up to 60 kts deep layer bulk shear at times,
so strong heavy thunderstorms are possible.

Temperatures continue to reflect the baroclinic zone, with
daytime insolation south of the front increasing the contrast
during the peak heating hours. Guidance was having a somewhat
difficult time with this.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 322 PM Friday...

east-west oriented stationary front at the beginning of the
period should push north of the area Saturday night with a cold
front then expected to sweep east on Sunday. As the cold front
pushes east, precipitation chances should end from the west.

Until the front pushes east, models indicate precipitation
chances will remain high with the highest QPF still expected
across the southeast Ohio counties as well as the West Virginia
counties adjacent to the Ohio River. Current thoughts are that
QPF values between 0.75 to 1.25 inches along and northwest of
the Ohio River with amounts near 0.50 inches elsewhere.

This heavy rain, coupled with the precipitation expected on
Saturday, should result in some main stem rivers experiencing
flooding on Sunday night and Monday. This is especially true
for the Ohio River, where major flooding is forecast along many
of our official forecast points. The current forecast levels
compare closely to Ivan in 2004, which produced significant
flooding along the Mighty Ohio.

An area of low pressure is then expected to move northeast
along the front, which may be located just to our southeast.
This will result in some scattered showers Sunday night into
Monday.

Temperatures will remain very warm on Sunday, with slightly
cooler temperatures Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 322 PM Friday...

High pressure will then take control of the weather with dry
weather anticipated Monday night into Tuesday night. A warm
front will then approach the region on Wednesday resulting in
increasing chances for showers. An associated area of low
pressure will push east on Thursday dragging a cold front across
the area.

Most areas should see wet weather Wednesday night and Thursday
with decreasing chance of showers by late Thursday. Airmass
could become cold enough for some of the precipitation to change
over to snow across the highest elevations Thursday night.

Went with a model blend for temps.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
As of 115 PM Friday...

Scattered showers and thunderstorms forming this afternoon can
bring MVFR tom IFR conditions, along with strong, gusty winds,
if one directly impacts a TAF site.

The chance for rain, and associated low MVFR to IFR conditions,
increases overnight tonight, and then is likely to continue on
Saturday, as waves of low pressure move northeastward, along a
front over the area.

Strong, gusty southwest surface winds will become light and
variable tonight, and then remain so for the most part on
Saturday. Moderate to strong southwest flow aloft will become
light to moderate south to southwest overnight tonight, and
then moderate to strong southwest again by Saturday afternoon.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY...

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing and degree of lower flight
categories may vary with timing of rain, and with possible fog
and stratus overnight tonight into Saturday. TAFs may need
updated if a thunderstorm approaches this afternoon or early
this evening.

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
EST 1HRLY       13   14   15   16   17   18   19   20   21   22   23   00
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    M
HTS CONSISTENCY  M    M    M    M    M    M    M    M    H    L    L    L
BKW CONSISTENCY  M    M    H    H    H    H    H    H    H    H    H    M
EKN CONSISTENCY  M    M    M    M    M    M    M    M    L    L    M    M
PKB CONSISTENCY  M    M    M    M    H    H    M    L    L    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    M    L    L    M    L    L

AFTER 18Z SATURDAY...
IFR possible at times in showers Saturday afternoon into Sunday.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Flood Watch through Sunday afternoon for WVZ005>011.
OH...Flood Watch through Sunday afternoon for OHZ066-067-075-076-
     083>087.
KY...Flood Watch through Sunday afternoon for KYZ101>103-105.
VA...None.

&&

$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...TRM
SHORT TERM...JSH
LONG TERM...JSH
AVIATION...TRM


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