-- Discussion containing changed information from previous version are highlighted. --
412
FXUS61 KRNK 201806
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
206 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/...
As of 1035 AM EDT Monday...

Key Message:

1. Dry and warm, with clouds early.

The area of stratus in the east has slowly eroded through the
morning, and out of the area. Morning low clouds and fog have
mostly dissipated, though areas of cumulus are still present
along the ridges and in the Foothills. Morning sounding at RNK
showed a large layer of dry air between about 750mb and 350mb,
which has helped decrease the cloud cover. No significant
changes made to the forecast this morning, only minor
adjustments to temperatures and sky cover.

Previous discussion below...

As of 200 AM EDT Monday...

An area of clouds was noted on satellite this morning, generally
from Warm Springs and Lynchburg, then southwest towards Boone.
Just inland from VA Beach, an area of stratus was slowly making
progress westward towards our southern Piedmont, but still
looks a couple hours away. In between these areas of clouds,
fog had developed. Drier air had allowed parts of the mountains
to drop into the 50s so far this morning, with Burke`s Garden in
the 40s.

A trough of low pressure was oriented over the Mid Atlantic and
into GA/Carolinas, with positively tilted high pressure from
the Gulf Coast towards NY State. An area of negative vorticity
will be steered over our area from the northeast today, on the
eastern side of the ridge. This will help squash precipitation
chances and decrease any lingering cloud cover after mid
morning. PWATs remain below an inch, and this combined with
highs in the 70s to low 80s and sunshine will make for a
pleasant day. The only chance for an isolated shower would be
over the far southern Blue Ridge this afternoon.

Tonight, winds become light and variable as high pressure
retreats east. Expect another shot of stratus migrating from
the coast Monday morning, possibly reaching the southern
Piedmont.

Confidence in the near term is high.

&&

.SHORT TERM /Tuesday Night through Thursday/
As of 150 PM EDT Monday...

-- Changed Discussion --
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 SUNDAY/...
-- 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.
-- End Changed Discussion --

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 135 PM EDT Monday...

VFR conditions are presently observed across the area, with
scattered to broken cumulus clouds, that will persist through
this afternoon and evening. Some clearing is expected overnight
as some drier air works into the area. Patchy fog may develop
early Tuesday morning, though not as widespread nor dense as
this morning. Similar to this morning, an area of stratus will
may its way inland from eastern VA, but this doesn`t look to
push as far inland as it did this morning, since winds will have
more of a southerly component than easterly. This may bring
lower ceilings to KDAN for a few hours Tuesday morning.
Otherwise, VFR conditions will continue through the TAF period,
ending Tuesday afternoon.

Overnight, winds will be light and variable, and turning
south/southeasterly by Tuesday afternoon.


EXTENDED AVIATION OUTLOOK...

VFR conditions persist into Wednesday, and possibly for parts of
the area the first half of Thursday. However, chances for
SHRA/TSRA increase beginning Thursday and continuing into the
weekend, as a front stalls across the area. This will bring
increasing periods of IFR/LIFR/MVFR conditions.

Winds will become more west/SW Wednesday through Friday.

&&

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

&&

$$

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