Area Forecast Discussion
Issued by NWS Charleston, WV

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FXUS61 KRLX 290713
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
213 AM EST Sat Feb 29 2020

.SYNOPSIS...
Snow tapers off late this morning. High pressure for the rest
of the weekend. A few systems will bring plenty of warm moist
air to promote rain for a greater part of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 830 PM Friday...

Expanded Winter Weather Advisory to include Wyoming, Logan and
Mingo counties in WV. Model consensus suggests snow showers will
spread across the Tristate area, east across extreme southern
sections of WV tonight. Around 1 inch of snow will be possible
across the Tristate area near HTS, east along and south of
interstate I64 to CRW, and 1 to 3 inches possible across
extreme southeast WV and southwest VA through 7 AM Saturday
morning. Therefore, a Winter Weather Advisory was expanded north
and west.

Tweaked hourly temperatures per latest surface observations
trends. Rest of forecast remains on track.

As of 230 PM Friday...

Main focus for the near term is a quick moving trough at the
surface and aloft that will slide through overnight. The main
forcing with this feature crosses the southern half of the
forecast area, generally south of I-64. Hi-res models are
indicating there will be a band of moderate snow transitioning
across KY, into southern WV or southwestern VA overnight. The
HRRR takes this into the very southern tip of the forecast
area, while the NAMNest keeps it south of the forecast area.
Opted to side with the HRRR, as the larger scale NAM and GFS
include the southern portion of the forecast area in some of the
better QPF print out too. This gives around 2 inches of snow
for this area, and have hoisted a winter weather advisory for
this. Have some concern about the next tier of counties north as
well with temperatures supportive of snow accumulations by late
tonight. Generally have amounts in the 1-2" range here, but if
things shift north at all, these would bump up to 2" pretty easily.
Opted to mention this potential in the HWO for now.

Have POPs tapering off very quickly around sunrise on Saturday,
as high pressure begins nosing in from the west.

Blended ECMWF MOS into previous temperature forecast, which
resulted in only minor changes.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
As of 200 AM Saturday...

For the start of the short term, high pressure ridging will be
in command associated with a surface high to our south. This
feature will drift east throughout Sunday promoting fair
and warm weather. Slightly above seasonable temperatures will
maintain into Monday keeping a warm weather trend for this time
of year. A southern stream disturbance is forecast to develop to
our southwest around Arkansas, eventually running into
southeast anti-cyclonic flow courtesy of the aforementioned high
pressure. This will transport a continuous supply of warm moist
air and rain through the area into Tuesday. Temperatures will
start out already above the seasonable norm and will climb even
more. Anomalously higher temps expected for Tuesday reaching
into the low to mid 60`s for much of the area. A frontal
boundary will then become stationary over the region and provide
a conveyor belt of continuous energy/moisture. So a warm and
wet start to the new week and to the month of March as well.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 200 AM Saturday...

While Tuesday may see a lull in rainfall totals, an upper level
trough sliding over Mexico will spawn a surface low which
should catch that southern stream of moisture and pair up with
the first feature, adding to the totals for the rest of Tuesday.
The GFS/Canadian models have a separate feature, a surface low,
developing to the west of us late Tuesday which will only
enhance rainfall. However, the Euro doesn`t want to agree with
them. Either way rainfall amounts are prog to ramp up a
significant amount with 1-2 standard deviations above the
climatological norm.

Wednesday will be interesting if the GFS solution holds true.
However, at this point models start to diverge greatly which is a
complete 180 from yesterday. We could get an abundance of
moderate to heavy rain for a good part of the day. With models
disagreeing so much, the takeaway from this is that we have to
keep an eye on how these systems evolve for the next day or so.
If the GFS is right along with the Canadian we are looking at a
lot of rainfall in just 2 days, finally ending sometime on
Thursday. According to GEFS ensembles during this span they are
expecting on average 2.5" inches of rain for Charleston. To
compare the GFS has 3.5 inches. Other locations have slightly
more. This will most likely provide water issues to the area and
we will have to focus on that aspect as this will be our main
concern going into midweek.

The warming trend will continue to take place and all
precipitation type will be rain except for maybe a few mountain
peaks during the overnight hours on Thursday/Friday. There`s a
possibility of more rain and even frozen precipitation as temps
finally turn back to normal for Friday although light
accumulations should be expected. There is fairly low confidence
for the end of the week into the weekend, therefore went with
central guidance and accepted slight to chance POPs for Friday
and according to guidance the rest of the weekend seems fairly
dry.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
As of 1245 AM Saturday...

MVFR conditions will persist for most sites at the beginning of
the period in ceilings, with the exception of possible IFR
ceilings at BKW. Most sites will see snow until the morning
hours with possible IFR visibilities due to the snow,
particularly at BKW, EKN, and CRW. As the snow ends, ceilings
should begin to raise back up to VFR ceilings. However, possible
upslope at EKN and CKB may prevent ceilings from rising for
these sites until later in the period. BKW is expected to
maintain MVFR ceilings until later in the period as well.

Winds begin from the northwest around 5-10KTs, persisting
through most of the period. Some sites may see gusts in the
morning/afternoon hours at around 15-20KTs.

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

FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Additional upslope snow in the mountains
later in the period. Restrictions in snow could be briefly lower
then 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.

DATE                                   SAT 02/29/20
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EST 1HRLY       01   02   03   04   05   06   07   08   09   10   11   12
CRW CONSISTENCY  H    H    M    M    H    H    H    H    H    M    H    H
HTS CONSISTENCY  H    M    M    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    M    M    H    H    H    H    M    M    H    M
EKN CONSISTENCY  H    H    M    H    H    M    L    M    M    H    H    L
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    H

AFTER 06Z SUNDAY...
No widespread IFR expected.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Winter Weather Advisory until 7 AM EST this morning for WVZ024-
     025-033-034.
OH...None.
KY...None.
VA...Winter Weather Advisory until 7 AM EST this morning for VAZ003-
     004.

&&

$$
SYNOPSIS...SL/CG
NEAR TERM...CG
SHORT TERM...JZ
LONG TERM...JZ
AVIATION...CG


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