-- Discussion containing changed information from previous version are highlighted. --
697
FXUS61 KRNK 172241
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
641 PM EDT Tue Sep 17 2024

.SYNOPSIS...
Low pressure centered over the Carolinas today will drift
slowly northeast tonight and through the overnight hours,
staying on the east side of the southern Appalachians, which
will keep a chance of rain in the area through tomorrow. The
low is expected to weaken and move offshore Thursday and
Friday, lowering the probability of precipitation areawide. Dry
weather and seasonal temperatures are expected for Saturday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 633 PM EDT Tuesday...

No major changes have been made to our latest forecast. However,
we have made a refinement to the most probable location of
isolated thunderstorms within an area that will be more prone to
convection. Areas near the VA/NC border generally east of I-77
have experienced some isolated thunderstorms, also in
association with some locally heavier rainfall. This area of
convection is expected to continue over the generally same
region over the next few hours. This activity has prompted a
Flood Advisory and a Flash Flood Warning for a portion of this
area. Continue to monitor our latest advisories and/or warnings
for updates for these situations, and also the potential for
any new advisories and/or warnings.

Have made minor changes to hourly temperatures, dew points, sky
cover and wind speed/gusts to better reflect the latest
conditions and expected trends through the evening hours.

As of 200 PM EDT Tuesday

Key message:

    - Isolated showers and mist look to continue areawide through
      Wednesday

The occluded surface low over northern South Carolina will continue
to fill in and remain quasi-stationary across the region into
Wednesday. Scattered showers today are expected to transition to
isolated showers with widespread light mist overnight tonight and
continue for the majority of Wednesday. This is primarily due to
occluded low remaining fairly stationary across southwestern North
Carolina overnight tonight and into Wednesday. This will keep weak
forcing for ascent coupled with PWATs in the 1.2-1.4 inch range in
place across the region. 850mb winds look to continue to decrease
significantly between this afternoon and Wednesday morning, which
will similarly reduce the amount of upslope flow across the eastern
peaks across the region. The only caveat for Wednesday is that some
surface based instability of around 500-1000 J/Kg of SBCAPE could
sneak into the Piedmont region tomorrow afternoon, which may enhance
some of the isolated showers that develop to produce some heavier
rainfall and lightning; however, confidence is not high at this time
as several CAM solutions do not bring those aforementioned levels of
instability into the region.

Overall, the potential for any flooding threat is diminished for
Wednesday as the combination of the weakening low, reduced forcing
for ascent, and a weakening LLJ are expected across the region. With
the occluded low in such close proximity to the the region, low
stratus and overcast conditions are expected areawide on Wednesday.
There will also be the potential for some isolated dense fog across
portions of the New River and Greenbrier valleys.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 215 PM EDT Tuesday...

Key Messages:

1) Showers are likely to continue across the area as an upper level
low lingers in the area through Friday.

2) The upper-low moves offshore late Friday, decreasing rain chances
and causing temperatures to rise for the weekend.

Rain chances continue for Wednesday night into Thursday, as an upper-
level low will remain stalled over the area. Wednesday night will
provide the best chance of rain in the period, with coverage
decreasing on Thursday as the upper-low weakens and slides east.
Cloudy and cool conditions will persist, with elevated winds winding
down by Thursday. Temperatures will remain slightly below to near
normal, with highs mainly in the 70s with higher elevations in the
60s. By Friday, the upper-low begins to move offshore into the
Atlantic, with shower chances lowering throughout the day as skies
clear out. This will allow temperatures to increase, with highs
reaching the low 80s in the piedmont locations. The Ensemble
Situational Awareness Table generally keeps QPF totals for Thursday
and Friday under 0.25 inches across the CWA. High pressure begins to
move back into the region, with dry weather expected heading into
the weekend.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 215 PM EDT Tuesday...

Key Messages:

1) Drier weather returns for the weekend, as high pressure builds in
with a wedge that may keep temperatures just below normal next week.

2) There is a chance that rain returns early next week, but there is
low confidence in this due to model disagreement.

This weekend will see high pressure begin to dominate the region
once again, drying things out with high temperatures in the 70s to
around 80 expected on Saturday. This high pressure over New England
will begin to wedge in the area on Sunday, which will cool
temperatures to slightly below normal and increase cloud cover in
the area. Highs will generally be in the low 70s with low
temperatures in the 50s. Late Monday, there is a chance for rain to
return to the region with a low pressure system that will move
across the Plains into the Ohio River Valley. However, confidence is
low due to model disagreement that the low will track into our area.
A slight chance of showers is kept in the forecast next week, but
regardless of rain chances, temperatures will remain near normal
through the forecast period.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 12:30 PM EDT Tuesday...

Widespread MVFR to LIFR ceilings are expected to continue
through the remainder of the afternoon and overnight hours.
MVFR visibilities in light to moderate rain look to continue
through the remainder of today, with IFR to LIFR Visibilities
developing overnight towards the early morning hours due to fog.
Gusty northeasterly to easterly winds today should diminish
through the evening and overnight as the surface low continues
to fill in and occlude over northern South Carolina. Light rain
across the area today is expected to transition to a heavy
drizzle starting overnight tonight. VFR conditions are not
expected to return to any terminals during the next 24 hour
period.


Average confidence for ceiling, visibility, and wind.


EXTENDED AVIATION OUTLOOK...

Periods of sub VFR conditions are possible through tomorrow, 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.

&&

.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...DS/EB
SHORT TERM...JCB
LONG TERM...JCB
AVIATION...EB
EQUIPMENT...AS/WP