-- Discussion containing changed information from previous version are highlighted. --
595
FXUS61 KRNK 171042
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
642 AM EDT Tue Sep 17 2024

.SYNOPSIS...
Low pressure centered over the Carolinas early this morning will
drift slowly northeast, staying on the east side of the southern
Appalachians, which will keep a chance of rain in the area through
Wednesday. The low weakens and moves offshore Thursday and Friday,
lowering the probability of precipitation. Dry weather and seasonal
temperatures are expected for Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 245 AM EDT Tuesday...

Key message:

    - Isolated chance of thunderstorms along the VA/NC border this
      afternoon

    - Continued low threat of flooding today

Surface low pressure staying to the south, over the Carolinas,  will
keep deep easterly wind across southwest Virginia, northwest North
Carolina, and southeast West Virginia. The low level jet starts
out at 40 to 50 knots this morning then gradually weakens to
around 15 knots tonight. The onshore flow and upslope component
of the wind will keep occasional rain over the area for the next
18 to 24 hours.

A majority of the models hold cloud cover in across the region. A
few do show breaks in the clouds over the piedmont this afternoon.
if there is some heating the shear is decent and Convective
Available Potential Energy could be as high as 1000 J/KG. Will keep
isolated thunderstorms along the VA/NC border this afternoon.
Overnight, fog and low clouds fill in, especially along and east of
the Blue Ridge.

Rainfall amounts as of 2AM ranged from around 0.25 inches to 1.25
inches across northern North Carolina and along the Blue Ridge
Parkway south of Roanoke. Most other locations had 0.25 inches or
less.

Similar to the temperature trends on Monday, clouds and rain will
hold down maximum temperatures. will be leaning towards 10th
percentile NBM and GLAMP guidance for maximum temperatures. Lows
tonight remain mild, around 10 degrees above normal.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 235 AM EDT Tuesday...

Key Messages:

1) Confidence is high for ongoing chances of showers through
Thursday due to a stalled upper level low.

2) Drier weather may arrive by Friday as the upper level low finally
moves eastward.

An upper level low will stall over North Carolina during Wednesday
and wobble slowly eastward on Thursday. The unsettled conditions
should continue with chances of showers during both days. There may
be a slight chance of thunderstorms in the Piedmont on Wednesday
afternoon, and that chance could move west of the Blue Ridge on
Thursday afternoon based on instability in model soundings.
Otherwise, it will remain cloudy and cool until the upper level low
moves closer to the East Coast on Thursday night. Rain chances
should reduce during Friday, and skies should begin to clear as an
upper level ridge builds eastward from the Plains. The ridge should
shove the upper level low completely offshore by Friday night.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 235 AM EDT Tuesday...

Key Messages:

1) Confidence is moderate for drier and milder weather on Saturday.

2) A cool wedge of high pressure may return for Sunday and Monday.

With an upper level ridge slowly moving eastward over the Ohio River
Valley on Saturday, drier and milder conditions should return.
Temperatures will rise towards normal values on Saturday with the
increased sunshine. The added heat and instability could spark an
isolated shower along the southern Blue Ridge during Saturday
afternoon. High pressure from eastern Canada should nose southward
by Sunday and could wedge against the eastern slopes of the Blue
Ridge. The resulting cool wedge of northeast flow may persist into
Monday across the Piedmont. There are some model disagreements
regarding a low pressure system crossing the northern Plains and
whether any of its moisture may reach the Appalachian Mountains by
late Monday.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 640 AM EDT Tuesday...

Widespread MVFR to LIFR ceilings this morning with VFR to MVFR
visibility in light to moderate rain.

Occasional rain will continue across southwest Virginia,
southeast West Virginia and northwest North Carolina through
00Z/8PM. Surface low pressure staying to the south, over the
Carolinas, will keep deep easterly wind across southwest
Virginia, northwest North Carolina, and southeast West Virginia.
The low level jet starts out at 40 to 50 knots this morning
then gradually weakens to around 15 knots tonight. The onshore
flow and upslope component of the wind will keep occasional rain
over the area for the next 18 to 24 hours.

Wind speeds and upslope lift gradually diminishes tonight.
Ceilings across the region will be IFR to LIFR with MVFR
visibility due to fog and intermittent light rain. Surface wind
gusts will drop below 20kts after 00Z/8PM.

Average confidence for ceiling, visibility, and wind.


EXTENDED AVIATION OUTLOOK...

Periods of sub VFR conditions are possible through Wednesday,
as a low pressure system brings rain and clouds to the area.

Thursday and Friday less coverage of showers is expected.

VFR conditions and dry weather is expected to return on
Saturday.
-- End Changed Discussion --

&&

.EQUIPMENT...
As of 135 PM EDT Monday...

The Lynchburg ASOS (LYH) is still experiencing data transmission
issues, mainly at night due to FAA outage. Please use caution
when using data from this site, as some may be missing.
No estimated date for return to full service at this time.

&&

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

&&

$$

SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...PW
LONG TERM...PW
AVIATION...AMS/RCS
EQUIPMENT...AS/WP