564
FXUS61 KRNK 180553
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
153 AM EDT Wed Sep 18 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 TODAY/...
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.

&&

.SHORT TERM /TONIGHT 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 /06Z WEDNESDAY THROUGH SUNDAY/...
As of 145 AM EDT Wednesday...

Primarily LIFR to IFR ceilings across the region. This trend is
expected to continue early this morning.

The southern edge of the cloud shield around the upper low was
approaching the Virginia/North Carolina border from the south.
As the clouds clear out, dense fog, with LIFR visibility, was
forming in the North Carolina piedmont. KDAN may have enough
breaks in the clouds before 12Z/8AM for LIFR fog to develop.

Ceilings will lift back to MVFR this afternoon. Clouds may also
becoming scattered west of the Appalachians, including for a few
hours at KBLF and KLWB.

Stratus and fog will redevelop across the region this evening
with LIFR ceilings and MVFR visibility by the 06Z/2AM end of the
TAF forecast period.

Winds will be from the east to northeast this morning, with a
few gusts up to 20 knots. By this afternoon and evening, wind
speeds will be less than 10 kts.

Average confidence for ceiling, visibility, and wind.


EXTENDED AVIATION OUTLOOK...

Thursday and Friday less coverage of showers is expected.

VFR conditions and dry weather is expected to return for
Saturday and Sunday.

&&

.EQUIPMENT...
As of 135 AM EDT Wednesday...

The Lynchburg ASOS (LYH) has been repaired. All data can now be
transmitted.

&&

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

&&

$$

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