587
FXUS61 KRNK 241919
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
319 PM EDT Tue Sep 24 2024

.SYNOPSIS...

A slow-moving cold front will meander along the Ohio River
Valley over the next several days, triggering rounds of showers
and thunderstorm activity that will persist through much of the
workweek. PTC 9 lifting northward from the Gulf of Mexico toward
the end of the work week may bring more widespread rainfall to
the region.

&&

.NEAR TERM /THROUGH TOMORROW/...
As of 200 PM EDT Tuesday

Key message:

1) An upper level trough and associated cold front will
approaching the region today will lead to continued shower and
thunderstorm activity overnight tonight and into the early
morning hours on Wednesday before becoming more isolated in
nature through Wednesday afternoon.

An upper level trough that has been digging southward today is
expected to separate from the main northern flow by Wednesday, and
become quasi-stationary across northeastern Arkansas and western
Tennessee. As this happens, upper level ridging is expected to build
across the southeastern coastal plain, and off the southeast
coastline. While This happens throughout the day on Wednesday, a
strengthening jet streak in a southwest to northeast orientation is
expected to develop from the lower Mississippi valley towards West
Virginia. This 250mb jet orientation coupled with upper level
divergent flow through the 500mb level will lead to scattered
shower and thunderstorm activity across the region for much of the
morning on Wednesday, with a possible break in the mid morning
before additional storms develop through the afternoon hours across
the I-77 corridor into West Virginia.  While much of the eastern
half of the area will dry out through the afternoon and evening,
cloud cover is expected to be plentiful across the region as mid and
upper level clouds from the south and southwest stream north. This
will keep temperatures in the low to mid 70s across higher terrain,
and in the upper 70s to near 80 across the Piedmont. Lows Wednesday
morning will generally fall into the low to mid 60s areawide.

&&


Short Term .../WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/
... As of 135 PM EDT Tuesday...

Key Messages:

1: Outer bands of TS Helene will cause showers as early as Thursday

2: Heaviest and most widespread rainfall will be Friday and Friday PM


Moisture convergence over a weak wedge will continue to cause
showers and embedded storms Wednesday night. TS Helene will still be
in the Gulf, but entering the influence of a closed 500mb low near
the Arklatex and MS. This low will accelerate Helene quickly
northward, going from the FL panhandle to western Carolina in the
span of just 12 hours. This could place the outer bands of tropical
moisture and rain in our NC counties as early as Thursday afternoon.
Friday looks to be the most active day, with rain expected for most
of the day throughout the CWA. Flooding will be a definite concern
as we expect 3-4" along the southern Blue Ridge and in the High
Country, and 1-3" across the remainder of the CWA. As always with
banding in tropical systems, due to the nature of banding there
could be higher amounts in localized areas.

Flooding concerns will be exacerbated by the enhanced winds,
particularly near and south of the NC/VA border. Above 3kft
elevation, winds could gust up to 30kt. This will blow down early
dead leaves, serving to clog up drains, culverts and sewers.


.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 200 PM EDT Tuesday...

Key Messages:

1) Lingering moisture from Tropical Storm Helene will remain in the
area through the forecast period, with showers possible each day.

2) High pressure wedges back into the region on Sunday, decreasing
rain chances and keeping below average temperatures through midweek.

As Tropical Storm Helene begins to dissipate over the Appalachian
mountains early on Saturday, remnant moisture and breezy conditions
will remain across the area. Rain chances decrease significantly on
Saturday but remain possible. High temperatures will be in the 70s,
with eastern piedmont locations around 80. For Sunday, surface high
pressure over New England will begin to wedge back into the RNK CWA,
pushing drier and cooler air southward. Residual moisture from
Helene will continue to ride over top of this wedge, leading to
light showers and cloudy conditions continuing into early next week.

Due to the cloud cover and high pressure wedge, temperatures are
expected to remain below normal beginning on Sunday. Highs will be
in the 60s and 70s, with lows in the 50s to around 60 degrees
through midweek. Winds also remain slightly elevated due to the
wedge. There is some model disagreement with where the remnant low
and associated moisture will go early next week. The Ensemble
Situational Awareness Table continues to keep precipitable water
values around 1.5 inches for early next week. Due to this, PoPs are
kept modest through the forecast period, with showers possible each
day.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 130 PM EDT Monday...

Clearing across southwest Virginia and southeastern West
Virginia has lead to scattered shower and thunderstorm
development across these regions over the last hour or so. This
will lead to VCTS conditions at KBLF, KLWB, KBCB, and KROA for
the next several hours and into the evening. As these showers
and thunderstorms pass near or over terminals, expect brief MVFR
to LIFR conditions. KDAN and KLYH look to remain under dense
cloud cover through the entire TAF period; however, TSRA
conditions look to impact both terminals through the overnight
hours. MVFR to LIFR conditions look to return to all terminals
beyond 0900 UTC Wednesday, and linger through 12-15 UTC on
Wednesday before conditions start to improve to MVFR to VFR
levels as visibilities increase, and CIGs lift.

EXTENDED AVIATION OUTLOOK...

MVFR/IFR stratus and fog are expected to occur in rounds through
at least the middle of the week, and increasingly likely to
persist through the end of the workweek. Rounds of showers and
thunderstorms will also continue to pass across the lower Mid-
Atlantic.

Low pressure lifting northward from the Gulf of Mexico toward
the end of the week may bring more widespread rainfall and sub-
VFR conditions to the region.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$

SYNOPSIS...EB/BMG
NEAR TERM...EB
SHORT TERM...VFJ
LONG TERM...JCB
AVIATION...EB/BMG