Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 220111
AFDRLX

Area Forecast Discussion
National Weather Service Charleston WV
811 PM EST Wed Feb 21 2018

.SYNOPSIS...
Cold front stalls over the southern sections overnight, and
meanders through the end of the week, with significant rainfall
possible into the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 800 PM Wednesday...

Adjusted PoPs according to latest radar images and high
resolution models. First batch of very isolated showers. Second
batch will move northeast across the area overnight. Third batch
of rainfall will be move widespread across southeast OH around
09Z and east of the OH River by 15Z Thursday.

As of 250 PM Wednesday...

A cold front currently over central portions of the CWA will
stall as the 1st of several low pressure waves ride up along
with it. NAM is further west and north with the GFS puts the
axis along or near the Ohio River. All other models are
somewhere in between. With the ground being saturated and and
streams and rivers just experienced flooding, it won`t take much
in the way of rain to cause flooding of small streams and creeks
and get the rivers to rise as well. Rain from this 1st wave
will set us up for the next wave on Friday into Saturday. So,
have issue an FFA for our Ohio river counties and SE OH counties
as 1st wave will pass over those areas starting 00Z Friday and
continuing through 12Z Sunday. This watch may have to be
expanded depending on where the heavier rains fall.

Temperatures were a consenus of model guidance and QPF from
OHRFC/WPC guidance.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 300 PM Wednesday...

The frontal boundary lifts back northward as a warm front
Thursday night with additional rain showers possible. Breaks in
the clouds toward the South and strong SSW flow bump Friday
afternoon temperatures back into the 60`s and 70`s. During
midday, strong upper level forcing along the boundary brings yet
another wave across the northeast Ohio River Valley where
1.2-1.5" PWAT exists generating moderate to heavy rainfall. At
this time, the axis of heaviest precipitation for this wave
looks to lie just north of our area in central Ohio through
northeast Ohio and western PA. However - we still anticipate up
to an inch of rainfall across our NW zones in eastern Ohio.
Another wave moves through Saturday during the day, again
generating moderate to heavy rainfall, with additional amounts
around an inch possible in SE Ohio and near the Ohio Valley.
These rains will lead to rises on streams and creeks and may
lead to localized flooding, hence the issuance of the Areal
Flood Watch. Rainfall amounts drop off fairly quickly to the
SE, but with the front moving back and forth through the area
with each passing wave, rainfall of some variety is likely
everywhere across the CWA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 320 PM Wednesday...

A welcome break in the synoptic pattern starts Saturday night as
a short wave trough rotates through the upper Plains and Great
Lakes Region. The strengthening jet ahead of it gives us one
more wave of moderate to heavy rainfall overnight before the
trough finally pushes this frontal boundary through the
mountains and to the East coast by Monday morning. Models tend
to dry this region out by sunset Sunday and high pressure
quickly moves in behind for a quiet Sunday night through the end
of the long term.

Rainfall totals may again be quite high in the Saturday
night/early Sunday timeframe, particularly in SE Ohio. Ohio
Valley counties including WV counties near the Ohio River, all
SE Ohio counties, and all NE KY counties could see an additional
half inch to 1". Elsewhere rainfall totals are looking generally
0.25-0.5" with the passage of the cold front.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
As of 150 PM Wednesday...

Cold front reaching the eastern mountains this evening. Rain
showers associated with front on and off at CRW, EKN and BKW
through midnight. Brief periods of MVFR/IFR possible under rain
showers.

Radar images show lots of breaks in the showers having scattered
showers this evening, but increasing in coverage and intensity
as an upper level wave move through overnight. Widespread
IFR/LIFR ceilings or visibilities can be expected after the
second batch of rainfall starting to spread from west to east by
06-09Z tonight.

A long period of IFR/LIFR conditions is anticipated during the
early morning hours as lower clouds and more rainfall affect the
entire area Thursday into Friday.

Winds behind the front are light from the north, but could be
gusty near showers and higher elevations.

Cold front expected to stall over the area with additional upper waves
of low pressure riding up and along the front through the week.


FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY...

FORECAST CONFIDENCE: High

ALTERNATE SCENARIOS: Timing of MVFR/IFR Conditions along and
behind the front 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.

DATE                                                                 THU
UTC 1HRLY       00   01   02   03   04   05   06   07   08   09   10   11
EST 1HRLY       19   20   21   22   23   00   01   02   03   04   05   06
CRW CONSISTENCY  M    M    M    H    L    M    L    L    L    L    L    L
HTS CONSISTENCY  M    H    H    H    H    M    M    L    M    M    M    L
BKW CONSISTENCY  H    H    M    M    M    M    M    M    M    M    M    L
EKN CONSISTENCY  H    L    H    M    L    M    M    M    L    M    M    L
PKB CONSISTENCY  H    H    H    H    H    M    M    M    L    L    M    L
CKB CONSISTENCY  H    H    H    H    H    H    L    L    L    L    L    L

AFTER 00Z FRIDAY...
IFR possible at times in showers Thursday night into the
weekend.

&&

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

&&

$$
SYNOPSIS...JS/MC
NEAR TERM...JS/ARJ
SHORT TERM...MC
LONG TERM...MC
AVIATION...ARJ


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