135
FXUS61 KRNK 230216
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
1016 PM EDT Sun Sep 22 2024

.SYNOPSIS...
A weak cold front will sink southward across the Piedmont
today, bringing a north-northeasterly wind shift to the lower
Mid-Atlantic. Another cold front will approach slowly from the
west tonight into Monday, bringing rounds of on-and-off shower
activity to region through much of the coming workweek. A return
of high pressure will bring drier conditions for the end of the
week.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 920 PM EDT Sunday...

Main adjustment this evening was with rain chances heading into
the hours leading up to sunrise Monday morning. Raised rain
chances for the morning hours as weak waves of low pressure make
their way across the mountains of southeast West Virginia.
Rainfall will be on and off through much of the day on Monday,
however, believe that much of the area west of the Blue Ridge
will receive something at times throughout the day. Otherwise,
modest adjustments made to temperatures and cloud cover as well.

As of 200 PM EDT Sunday...

Key Messages:

1) First day of fall living up to its name!

2) Clouds increase tonight after sunset, with showers moving in
from the west towards morning.

3) Periods of showers and storms throughout Monday, mainly for
the mountains.

A backdoor front was in the process of sinking south across the
eastern part of the forecast area, allowing cooler and drier air
to filter in from the north. This could be seen in the visible
satellite imagery this afternoon, as stratus remained socked in
over eastern and central VA, east of a Buena Vista to Lynchburg
to Danville line. Temperatures there were in the low to mid
70s, while to the west temperatures were in the low 80s to mid
80s under full sunshine.

Aloft, troughing over the western Atlantic will continue to
drift east, allowing weak ridging to shift east as well. This
will put the Mid Atlantic region right in the path of a stream
of upper level energy in due westerly flow, and will help fuel
showers and thunderstorms throughout the day Monday, at least
for part of the area. CAMs seem to show a first wave of
showers developing mainly between 5 and 9 AM over the western
mountains. To the east, wedging high pressure will support dense
fog and stratus, and less convection. Overnight lows will be in
the upper 50s to mid 60s.

After a brief break in the rain and perhaps some partial
clearing in the late morning to early afternoon hours, another
stronger area of showers and storms will arrive ahead of a cold
front. This area of storms will arrive in a semi-linear
fashion, and again will impact the mountains and foothills most.
Moderate to heavy rain leading to flooding looks to be the main
concern. An isolated damaging wind gust is possible, but any
significant severe weather is not likely due to morning clouds,
stratus, and overall lack of instability. Temperatures will
reach the low to upper 70s, with cooler readings over the east.

Confidence in the near term is moderate.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 200 PM EDT Sunday...

Key Messages:

1: Daily showers and storms for the first half of the week

A frontal system will begin to move into the OH River Valley
from the plains, and lift a nearly stationary front in the
Mid-Atlantic back to the north. Along with an incoming cold
front to the west, this setup places us in the warm sector with
significant southerly flow and moisture convergence. Looking at
instability on Tuesday and Wednesday afternoon, CAPEs are
generally between 500-1000J/kg, which are certainly high enough
to force some convection and a few storms amongst the showers.
The high levels of moisture and blanket of cloud cover will hold
onto heat in the overnight periods, keeping overnight lows
above normal, but preventing extensive surface heating during
the day, and holding daytime highs around or just under normal
in the mid to low 70s for most.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 130 PM EDT Sunday...

Key Messages:

1) Showers and a few storms will be possible for Thursday, with
precipitation chances decreasing for Friday into the weekend.

2) A potential tropical system in the Gulf of Mexico could bring
impacts to our area next weekend, but confidence is currently
low.

An upper-level trough will move across the northern US later
this week and move over the Ohio River Valley. This along with
highs in the 70s to around 80 degrees will allow enough lift
for showers and storms to occur across the area on Thursday.
Friday will have similar conditions but increasing cloud cover
will keep high temperatures in the low to mid 70s into the
weekend. High pressure over New England builds and begins to
wedge in across the CWA on Saturday. This will decrease rain
chances, but heavy cloud cover with upslope flow will persist
with a few showers still possible.

Confidence in this forecast remains very low, as models are in
disagreement over the timing and location of the upper-level
trough previously mentioned. This trough will also play a very
important factor in the timing and direction of a potential
tropical disturbance in the Gulf of Mexico later this week.
Models are inconsistent with each run, having the system track
anywhere between the southern Ohio River Valley to along the
East Coast. The GFS and ECMWF MSLP ensemble members generally
have the system tracking into the southern Appalachians or just
to the west into Tennessee, but each run has not been consistent
to this point. Regardless, there is an increasing chance that a
tropical system may head towards our CWA next weekend, but
confidence remains low for any impacts that may occur.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 820 PM EDT Sunday...

Satellite imagery indicates that stratus is beginning to fill in
across the Piedmont this evening as easterly windflow draws
marine air across the region. This will continue to fill in as
the night progresses. Showers will move across the mountains of
southeast West Virginia toward dawn on Monday, though
questionable how far south they will extend. Do have rainfall
mentioned in TAFs tomorrow, though expect the rain will be on
and off through much of the day, and generally light in
intensity. Better chances for rain will be across the mountains
during the morning and afternoon, with showers finally making
it across the Piedmont during the evening. Winds will remain
less than 10kts through the period.


EXTENDED AVIATION OUTLOOK...

LIFR/IFR stratus and fog are expected into Tuesday morning.
Daily chance of showers, thunderstorms, and lingering sub-VFR
conditions continue Monday afternoon through at least the week
as several systems affect the region.

&&

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

&&

$$

SYNOPSIS...NF/SH
NEAR TERM...NF/SH
SHORT TERM...VFJ
LONG TERM...JCB
AVIATION...NF/SH