293
FXUS61 KRLX 160654
AFDRLX

AREA FORECAST DISCUSSION
National Weather Service Charleston WV
254 AM EDT Mon Sep 16 2024

.SYNOPSIS...
Dry weather, and elevated fire danger, continues today under
strong high pressure. An area of low pressure off the Atlantic
coast brings the next chance of rain mid-week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 240 AM Monday...

Light easterly flow today picking up slightly by the afternoon
with occasional gusty conditions expected along the higher
terrain. Very dry conditions in the low levels courtesy of high
pressure anchored to our north will likely mix down and keep the
area dry and relatively cloud free other than mid to high
clouds coming in off of the tropical system along the Atlantic
coast. The afternoon mixing will drop RH values down into the
20s and 30s across the lowlands with slightly higher values
along the mountains, however the mountains will have stronger
gustier conditions.

With the anticipation of a fairly solid deck of mid to high
clouds spreading across from east to west throughout the area
by this afternoon will likely suppress some daytime heating,
therefore elected to use guidance with lower temperatures
keeping temperatures slightly below central guidance which
equated to a lot of the area not forecast to reach the 80
degree mark. Areas along and west of the Ohio will likely see
higher temperatures due to having the longest time without
dense cloud coverage.

Slight chances for showers will appear in the forecast for
the afternoon across southeastern WV and these chances will
continue to spread inward and toward the northwest into the
evening, eventually making it all the way across the area by
early Tuesday morning.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 150 PM Sunday...

Key Point:

* Considerable model differences remain regarding low pressure
  off the Atlantic Coast yielding a low confidence forecast

Upper level ridging over the northeast gradually erodes/shifts
eastward Sunday night into Monday. This opens the door for a
area of (currently) non-tropical low pressure off the Carolinas
coast that could begin to take on some tropical characteristics
and potentially move inland starting as early as Monday.
Ensemble families are beginning to show some more consistent
clustering with solutions, inclusive of operational guidance,
this roughly falls into 2 camps:

1.) A northwesterly track as it approaches shore where central
low pressure moves into the TN Valley. This solution is most
common among GEFS ensemble members as well as the latest GFS
runs ending 06Z and latest NAM runs ending 12Z. This solution
would result a belt of relatively strong easterly low level flow
transporting tropical moisture into the region. While some rain
shadowing will take place with this belt of strong flow nearly
normal to our terrain, could see some pockets of decent rainfall
farther west, generally outside where the typical warm wedge
sets up, coincident with strong mass convergence where the wind
field begins to weaken. Non-mesoscale guidance with this
solution is likely too high with rainfall amounts in the rain
shadow if this solution were to verify, the 12Z mesoscale NAM
may be a reasonable answer for this solution though. The
headline here would be potentially beneficial rainfall for at
least portions of the D4 drought area north of the Kanawha
Valley. Heading toward the long term portion of the forecast,
this would also tend to have a longer loiter time of tropical
moisture over the region yielding continued unsettled weather
through the end of the week.

2.) A northerly track as it approaches land that moves up the
Atlantic Coastal plain. This solution is currently favored by a
majority of GEPS/EPS members, UKMET, operational Canadian/ECMWF
and a few GEFS members. It is also the basis for the WPC
forecast from the last cycle. This solution would minimize
barrier normal flow, but also limit westward expansion of the
tropical moisture plume with predominately north-northeasterly
flow across the region. This would confined a bulk of any 1+
inch rainfall totals to the mountains and adjacent foothills
with the highest totals across our northeast. Although there are
some members of this solution that would not eject the tropical
moisture out to the north, this would generally yield a quicker
return to dry conditions by the end of the week.

Overall, confidence in the forecast remains low with ranges in
interquartile 48hr QPF values in central guidance from
effectively no rainfall to near what the deterministic values
were in the last cycle. For now, will continue to largely defer
to central guidance for the deterministic forecast, if, for
nothing else, to at least maintain some consistency with our
neighbors. Highly confident that the deterministic forecast will
change substantially over the next 24 to 36 hours, also fairly
confident that some locations will see some beneficial rainfall,
with the highest confidence along and upwind of the highest
terrain.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 150 PM Sunday...

Uncertainty remains very high through the remainder of the
extended forecast owing to potential placement of residual
moisture from the low off the coast mentioned in the short term
discussion. In the absence of lingering tropical moisture,
expected sensible weather would be minimal as high pressure
builds back into the northeast.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
As of 130 AM Monday...

For this TAF period expecting VFR to dominate. Flow will be
easterly at around 5KT across the area with stronger flow along
the mountains particularly at BKW where gusts up to 20KT can be
expected during the day. That site will endure some llws this
evening temporarily until surface winds pick back up. Mainly
just high clouds today spreading across the sky which will
become likely overcast by this late afternoon.

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

FORECAST CONFIDENCE: High.

ALTERNATE SCENARIOS: None.
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 09/16/24
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  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    M    L    L    L    L    M    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    L    L    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z TUESDAY...
Widespread IFR conditions are not expected at this time.

&&

.FIRE WEATHER...
As of 300 AM Monday...

Dry weather persists at least through the afternoon.

Very dry air aloft will mix down to the surface during daytime
mixing hours today. Minimum relative humidity values expected
into the 20 to 30 percent range across the lower elevations,
with slightly higher values in the higher terrain. Easterly
winds will continue to gust to between 15 and 25 mph at times
across the ridges. Approaching clouds from the east-southeast
may help to mitigate such a rise in afternoon high temperatures
today.

The next potential chance for rain is Tuesday into Thursday in
association with a low pressure system originating in the
Atlantic, and then any potential lingering tropical moisture
associated with it. Confidence in placement of precipitation is
low at this time given model spread. The best chance of
beneficial rainfall will be along and east of the higher
terrain, but can`t rule out some beneficial rainfall farther
west.

&&

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

&&

$$

SYNOPSIS...TRM/JZ
NEAR TERM...JZ
SHORT TERM...JP
LONG TERM...JP
AVIATION...JZ

FIRE WEATHER...MEK/FK/JP