-- Discussion containing changed information from previous version are highlighted. --
790
FXUS61 KRNK 170554
AFDRNK

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

.SYNOPSIS...
Tropical Cyclone Eight has moved onshore this evening and
drifts through the Carolinas through Wednesday, bringing a
prolonged period of rain to the area. A low probability of rain
remains in the forecast through the end of the week as high
pressure wedges down the Appalachians.

&&

.NEAR TERM /THROUGH TODAY/...
As of 720 PM EDT Monday...

Update: Tropical Cyclone Eight will move inland and track
across the Carolinas through Tuesday. Meanwhile, dry high
pressure has kept most of the area rain-free today. The
environment will continue to saturate overnight with light to
moderate rain falling along and south of the VA/NC border. With
an easterly flow in the low and mid levels, feeder bands with a
long fetch from the Atlantic could produce 2 to 4 inches of rain
along eastern slopes of RNK`s southern Blue Ridge (Roanoke VA-
Watauga NC) tonight into Tuesday night. At this time, no
flooding is expected, but creeks and streams levels will rise.

Previous Discussion as of 120 PM EDT Monday...

Key message:

    - Rain spreading in this afternoon and evening becoming
      moderate to heavy at times along/east of the Blue Ridge
      into Tuesday
    - Northeast-east winds increasing with gusts to 20-35 mph


Low still centered off the SC coast this afternoon expected to
move inland by late afternoon between CHS-ILM. Rain already
reaching the NC mountains but drier air north has kept it
limited. Leaning toward 12z 3km NAM as it had the setup with
the rain and storm better. Better lift arrives by mid- late
afternoon and moreso tonight into Tuesday as the low moves
inland to upstate SC by Tuesday morning, weakening considerably
by Tuesday afternoon. Stronger winds stay below advisory levels
but upped gusts a little especially over our NC and southern VA
counties. Some gusts over 30 mph may lead to weaker trees or
limbs to fall. Rainfall of 1-3+" over a 24-36 hr period should
limit flooding concerns given how dry we have been, so no flood
watches at this time. Rises mainly expect along the upper New
River and lower Roanoke/Dan basin from this event but staying
well below flood stage given low flows.

PWATS off our 12z RNK sounding hanging around 2/3" but should
jump to over an inch by this evening and over 1.5"-2.0" tonight.

Several bands of heavier rain and enhancement along the Blue
Ridge takes shape overnight into Tuesday but models keep the
rain/showers moving along which unless there is training should
limit amounts for most. As far as instability that also looks
fairly limited but could see a few lightning strikes over
southern VA into the NC piedmont Tuesday.

Temperatures run above normal tonight with mid to upper 50s in
the mountains to mid 60s piedmont. Clouds/showers will keep
temperatures below normal Tuesday with 60s in the mountains and
lower 70s east.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
As of 1245 PM EDT Monday...

Key Messages:

1. Rain chances continue through the midweek.
2. Highest chances for rain Tuesday night through Wednesday.
3. Near to below normal temperatures.

The remnants of Potential Tropical Cyclone 8 will slowly move into
the Carolinas through Tuesday, bringing rounds of moderate to heavy
rainfall to the area. Models have generally shifted the track of the
system farther southwestward, but some uncertainty exists after
Wednesday where the remnants of this system may go, with no strong
feature aloft to steer it in any specific direction. That being
said, forecast confidence after Wednesday decreases, but overall,
chances of rain continue through the midweek, possibly into the end
of the week, as the remnants of PTC 8 meander near the Carolinas and
Tennessee Valley. The majority of the rain will fall Tuesday, but
continue into Wednesday. Repeated rounds of rainfall will increase
the risk of flooding, but dry antecedent conditions will help
to limit flooding potential. The track of this system will
influence rainfall amounts through the period, but highest
amounts still look to be along the Blue Ridge, particularly over
the southern parts of the mountains, in northwest NC and
southwest VA. Some instability and bulk shear around 30 knots
associated with the system as it pivots into and through the
Carolinas could lead to a few thunderstorms Wednesday and
Thursday afternoon, though confidence is low.

With cloud cover and chances for rain through the period, expecting
temperatures to be near to below normal.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 100 PM EDT Monday...

Key Messages:

1. Chances for rain continue into the weekend, but gradually
decrease.

2. Near to below normal temperatures through the period.

With the remnants of Potential Tropical Cyclone 8 still in the
vicinity, rainfall chances continue into the end of the work week,
mainly for central and eastern VA and NC. However, an upper ridge
building over the central US will start to push the upper trough/low
associated with the remnants of the system out towards the Atlantic.
Surface high pressure moves into the northeast US again by the
second half of the week, and start to wedge along the eastern side
of the Appalachians. With the wedge in place, any rain would
have to overcome the dry air, and so will help to lower rain
chances through the weekend. That all being said, look for
increasing periods of sunshine after Friday through the weekend.
Temperatures will be near to below normal for this time of year
through the forecast period.
-- End Changed Discussion --

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 145 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. Little change in
flight conditions are expected. Winds will gust 20 to 30 kts.
Have added LLWS in the KROA, KBLF, and KLWB TAFs while the low
level jet is 40 to 50 knots.

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 Thursday, as
a low pressure system brings rain and clouds to the area
through the midweek. Thursday and Friday less coverage of
showers is expected.

VFR conditions and dry weather is expected to return on
Saturday, but confidence is low.
-- 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/WP
NEAR TERM...RCS/WP
SHORT TERM...AS
LONG TERM...AS
AVIATION...AMS/RCS
EQUIPMENT...AS/WP