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000 
FXUS61 KRLX 210738
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
338 AM EDT Mon Oct 21 2019

.SYNOPSIS...
Warm front today with much warmer conditions. Rain tonight into
Tuesday with a cold front. High pressure builds in for midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 234 AM Monday...

Morning fog and low clouds will mix out by mid morning (if not 
sooner) as a southeasterly LLJ strengthens in response to the 
next storm system approaching from the west. The southeasterly 
low level flow will translate to an adiabatic warming component 
today, resulting in a drying and warming effect in the lower 
levels of the atmosphere. Thus, plenty of sunshine is expected 
for much of the daylight hours (although may eventually become 
filtered by thickening upper level cloudiness as the H25 jet 
shifts into a greater meridional position). 

An elongated lobe of vorticity in the H5 flow is prog to advect
NE across the area mid/late afternoon, which could result in
some patchy light rain across the E/SE CWA. Will keep today dry,
however, given aforementioned expected low level drying in the 
afternoon.

Chances of rain will then increase from west to east tonight,
especially during the second half of the night, as a cold front
pushes east towards the area. 00z guidance suites have backed 
off a bit on expected rainfall amounts, but there should still 
be some embedded areas of moderate rainfall overnight. A minimal
threat of lightning will exist, primarily associated with 
forcing along the immediate sfc front.

Breezy southeasterly surface winds will develop throughout today
as the LLJ strengthens. It should be notably gusty at times from
midday through the afternoon as momentum transfer maximizes
during this time frame. 

Max temps today will be quite warm for areas west of the 
mountains. Locations across western WV and SE OH should flirt 
with/exceed the 80 degree mark for afternoon highs. Areas east 
of the ridges are likely to remain rather cool/chilly today as 
cooler air remains compressed along the terrain from the 
persistent SE flow.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
As of 230 AM Monday...

The cold front and its associated rainfall will continue to
progress eastward at the start of the short term period. Low
pressure developing on the southern extent of the front in the 
Mississippi Valley will scoot just southeast of West Virginia
Tuesday, with an additional half an inch of rainfall expected 
to fall east of the Piedmont. The boundary will pick up speed as
it crosses the mountains, sprinting out of the forecast area by
the middle of the afternoon on Tuesday.

Expanding high pressure over the southern Gulf states will push
the front farther offshore, returning Central Appalachia to
a quiet and dry spell by midweek through Friday morning. During
which time, afternoon highs will hover around average in the 
mid 50s for the mountains and low to mid 60s for the lowlands. 
Overnight lows will be chilly across the mountains, especially 
Thursday morning when the boundary layer is most likely to 
decouple, which could lead to areas of patchy frost in Randolph 
and Pocahontas Counties.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
As of 230 AM Monday...

The forecast for the end of the work week remains uncertain
between guidance. The surface high will migrate over the Mid-
Atlantic region by Thursday afternoon, which global models 
agree upon, but what happens beyond that is where consensus goes
astray. The GFS has the high departing into the Atlantic early
Friday morning, making room for a plume of moisture riding up 
into the Ohio Valley from the Arklatex region, shearing apart 
in the process, but leading to two separate concentrated areas 
of rain encroaching on the forecast area. The ECMWF and Canadian
have drier solutions, with the aforementioned high remaining 
parked over the Delmarva area and preventing moisture from 
marching in from the Central Plains until later on in the 
weekend. Given this spread in guidance, have maintained 
persistence from central guidance and went with a chance of rain
starting Friday morning and lasting through the remainder of 
the long term.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
As of 117 AM Monday...

Variety of aviation impacts expected at times during the TAF
period.

Areas of both radiation and advection fog are impacting 
portions of the region early this morning, while areas of lower 
end MVFR CIGs from stratocu transitioning to stratus are 
impacting other areas. Long story short, prolonged periods of 
LIFR/VLIFR are likely overnight for KEKN/KCKB/KCRW and early in 
the TAF period at KBKW. KHTS should experience MVFR CIGs before 
cloud shield moves out later in the night with fog then 
possibly developing at that time. KPKB likely to start off at 
VFR with flight rules deteriorating overnight as fog develops.

Fog conditions may improve later tonight as a SErly LLJ
develops. Later during the sunlight hours of Mon morning, a
return to areawide VFR is expected. Flight rules likely to
deteriorate again late tonight, and especially just beyond valid
TAF period as areas of RA develop across the region.

Weak winds early in the TAF period, becoming SErly 5 to 10 kts
this morning, and then gusty (gusts around 20 kts at times) 
from the SE this afternoon. A few gusts of 25 to 30 kts possible
during the afternoon at KBKW.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
     
FORECAST CONFIDENCE: Medium.

ALTERNATE SCENARIOS: Timing of fog development/improvement, as
well as timing of potential low CIGs is rather uncertain. Rain
may arrive sooner than forecast 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.

DATE                              MON 10/21/19
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  M    M    H    L    L    L    L    M    H    H    H    H
HTS CONSISTENCY  M    M    M    M    H    H    H    H    H    H    H    H
BKW CONSISTENCY  M    M    M    L    M    M    M    M    M    M    H    H
EKN CONSISTENCY  L    M    M    M    M    M    M    L    L    H    H    H
PKB CONSISTENCY  H    H    M    L    L    L    L    M    H    H    H    H
CKB CONSISTENCY  L    L    M    L    L    L    L    M    H    H    H    H

AFTER 06Z TUESDAY...
IFR conditions possible with rain Tues morning.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.

&&

$$

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