-- Discussion containing changed information from previous version are highlighted. --
657
FXUS61 KRNK 202250
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
650 PM EDT Mon May 20 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 TUESDAY/...
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As of 650 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.

An area of surface high pressure along the East Coast will keep
conditions dry through tonight and tomorrow. East to northeast
flow continues to advect some moisture from the Atlantic Ocean
towards the Appalachian Mountains, which contributed in a
considerable amount of cumulus clouds earlier this afternoon.
Isolated showers are currently observed on radar in western
Greenbrier County and in parts of Ashe and Watauga counties. The
chance of any thunderstorms developing in those areas appears
to be quite low this evening, and this activity should diminish
after sunset.

Some patchy fog may develop later tonight into tomorrow
morning. In addition, another area of stratus clouds is
expected to push inland from eastern Virginia that could reach
locations east of a line from Danville to Lynchburg. Similar to
earlier this morning, these clouds will retreat back towards
the coast later on Tuesday. Temperatures were pushed upward for
Tuesday as the flow will turn more towards the southeast to
increase warm air advection. This extra warmth should fuel more
instability to spark a couple showers and thunderstorms west of
the Blue Ridge by Tuesday afternoon.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
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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.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
-- Changed Discussion --
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.
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&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
As of 650 PM EDT Monday...

VFR conditions are expected at all terminals for this evening.
As a repeat from earlier this morning, a layer of stratus
clouds could move inland from eastern Virginia by early tomorrow
morning but may not quite get to DAN and LYH as the flow will
be more out of the southeast. Some patchy fog may also impact
most terminals by tomorrow morning. Any clouds and fog should
diminish on Tuesday with VFR conditions anticipated through the
remainder of the day. The only exception will be a chance of
isolated showers and thunderstorms west of the Blue Ridge by
Tuesday afternoon.

EXTENDED AVIATION OUTLOOK...

VFR conditions will continue into Wednesday with the flow
turning more towards 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
frontal boundary arrives. This frontal boundary 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...PW