-- Discussion containing changed information from previous version are highlighted. --
327
FXUS61 KRNK 210614
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
214 AM EDT Tue May 21 2024

.SYNOPSIS...
High pressure will keep our area mostly dry through Wednesday.
Showers and a few thunderstorms return Thursday and linger into
the weekend as a frontal boundary stalls over the area.
Temperatures will be near or a few degrees above normal for
much of the week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 915 PM EDT Monday...

Key Messages:

1) Confidence is high for dry and warm weather through Tuesday.

2) Patchy fog and low clouds are possible by tomorrow morning.

Only minor tweaks to temperatures were made for this update, but
everything in the forecast appears to be on track. An area of
surface high pressure along the East Coast will keep conditions
dry through tonight and tomorrow. The isolated showers in
western Greenbrier County and in parts of Ashe and Watauga
counties have dissipated. Cloud cover from earlier today has
mostly diminished across the area for now. Low temperatures
tonight should mainly reach the 50s.

Some patchy fog will develop by early tomorrow morning. In
addition, another layer of stratus clouds is expected to drift
inland from eastern Virginia that may reach areas east of a
line from Danville to Lynchburg. Similar to earlier this
morning, these clouds will retreat back towards the coast later
on Tuesday. The flow will turn more towards the southeast to
increase warm air advection and push high temperatures into the
mid 70s to the mid 80s. This extra warmth should fuel more
instability to spark a couple showers and thunderstorms west of
the Blue Ridge by Tuesday afternoon.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
As of 150 PM EDT Monday...

Key Messages:

1) Increasingly unsettled weather expected through the period.

2) Temperatures near to slightly above seasonal normals.

The elongated upper ridge that was over the region Monday and
Tuesday will shift east into the western Atlantic. Broad
troughing in the central U.S. with a series of embedded upper-
level disturbances will begin to impinge on the region resulting
in an increase in mainly diurnal convection through this
period. For Wednesday, the bulk of the activity will be along
and west of the Blue Ridge, but all areas will see a good chance
for precipitation by Thursday, with showers and thunderstorms
likely west of the Blue Ridge and especially across the
mountains of West Virginia and southwest Virginia. The severe
threat looks to be low at this point, with the main concern
heavy rainfall on saturated ground given events of the past few
days. Nonetheless, isolated strong to severe thunderstorms
cannot be completely ruled out, especially on Thursday.

Temperatures will be warm, but moderated by the increase in
clouds and precipitation. The largest deviation from normal
temperatures will be at night/early mornings, where with
dewpoints in the 60s, it will become increasingly mild and
muggy at night. Urban areas such as Roanoke may remain close to
70 degrees at night during the later half of the week. High
temperatures will be mostly 70s west of the Blue Ridge to lower
and mid 80s east of the Blue Ridge.

/Confidence Levels in Forecast Parameters/
- Moderate to High Confidence in Temperatures,
- Moderate to  High Confidence in Precipitation Probabilities,
- Moderate Confidence in Wind Direction and Speed.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 200 PM EDT Monday...

Key Messages:

1) A very wet period with localized flooding possible an
increasing threat going into the weekend.

2) Mild muggy nights, a bit cooler during the daytime.

A series of upper-level disturbances will track from the central
U.S. into the eastern U.S. through the period. Eventually this
will evolve into a deepening upper trough anchored over the
Great Lakes. Beyond this time frame, this upper trough will
result in a trend toward much cooler/damp conditions
unfortunately just in time for Memorial Day. A frontal system
will slowly move through the area over the weekend resulting in
widespread showers and thunderstorms. As noted above, the main
concern will be heavy rainfall and an increased threat for
flooding. We have added this mention to the extended portion of
the HWO. While the severe threat looks low, it is certainly non-
zero. At a minimum, wet microbursts are possible.

Maximum temperature are expected to remain relatively near
seasonal normals with a slight cooling trend from midweek to the
weekend as clouds and precipitation coverage increase. Look for
lows mostly in the 60s with urban areas hovering near 70 at
night as dewpoints linger in the 60s. Memorial Day will turn
notably cooler under the upper trough and we could see highs in
the 60s mountains with mainly 70s elsewhere with lows dipping
back into the 50s.

/Confidence Levels in Forecast Parameters/
- Moderate Confidence in Temperatures,
- Moderate to High Confidence in Precipitation Probabilities,
- Moderate Confidence in Wind Direction and Speed.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 205 AM EDT Tuesday...

Areas of fog over central and eastern Virginia and North
Carolina were resulting in MVFR to LIFR visibilities early this
morning. LIFR stratus moving onshore in eastern Virginia is
expected to stay east of KLYH and KDAN this morning. River
valley fog is also likely to develop along the Greenbrier and
New Rivers, impacting KLWB before 12Z/8AM this morning.

The fog will dissipate by 14Z/10AM, then scattered to broken VFR
stratocumulus will develop this afternoon over the mountains
and foothills. Isolated showers and thunderstorms are expected,
especially along the southern Blue Ridge. Because the coverage
will be isolated, local TAF sites may not be impacted by these
storms. For now only have VCSH mentioned at KBLF and KLWB.

Any showers and thunderstorms will erode this evening, after
00Z/8PM with the loss of heating. MVFR/IFR fog will form again
overnight in the piedmont.


Average confidence for ceiling, wind, and visibility.


EXTENDED AVIATION OUTLOOK...

VFR conditions will continue into Wednesday with the wind turning
to the southwest. The chance of showers and thunderstorms will
gradually increase in the mountains by Wednesday afternoon and
become more widespread by Thursday as a front arrives.

This front will stall by Friday across the Mid Atlantic and
linger through Saturday. Waves of low pressure riding along this
boundary will spark more showers and thunderstorms and increase
the likelihood of low ceilings during this time.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...PW/SH
NEAR TERM...AS/PW
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS/PW