860
FXUS61 KRNK 220049
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
849 PM EDT Tue May 21 2024

.SYNOPSIS...
High pressure passing overhead to the east will provide dry
weather for most locations through tonight. Increasing moisture
pooling ahead of an approaching cold front will bring widely
scattered showers and thunderstorms for Wednesday and Thursday.
This activity will increase in coverage through the weekend as
the low pressure system tracks toward the eastern United States.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 830 PM EDT Tuesday...

Key message:

 - Mild temperatures through the near term
 - Isolated showers

Convergence along the spine of the appalachians is leading to a
a few showers/thundershowers, but coverage is pretty isolated.
That said, in spite of the isolated coverage, the showers that
did occur were very rain efficient. Upwards of 2.5 inches of
rain occurred over parts of central and southern Grayson County,
VA, this evening.

In general, any shower/storm activity will fade quickly, leaving
us will a mainly clear but mild overnight. With light winds and
mostly clear skies overtop moist soils from recent rainfall,
patchy fog will redevelop after midnight, particularly in the
river valleys. Overnight lows will bottom out in the mid 50s to
around 60 degrees.

For Wednesday, winds will shift more from the south as high
pressure moves away and a cold front approaches from the west.
Will start the day with fog burning off quickly and otherwise
abundant sunshine. By mid afternoon, expect another round of
widely scattered showers and thunderstorms to develop, mainly
for the mountains. Afternoon highs will be a few degrees warmer
than todays, reaching into the upper 70s to the mid 80s
areawide.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 130 PM EDT Tuesday...

Key Messages:

1. Daily chances of showers and storms through the period.
2. Locally heavy rain possible Thursday and Friday.
3. Temperatures near to just above normal.

A cold front approaches the Mid Atlantic from the west by late
Wednesday into Thursday, and will bring unsettled weather to the
area through the end of the work week. This front stalls over
the eastern US, resulting in near daily chances of showers and
thunderstorms, highest chances along and west of the Blue Ridge
on Thursday and Friday as mid level shortwaves track across the
area. Precipitable water values will increase as the front
continues to move closer to the area, with forecast values near
or exceeding the 90th percentile relative to climatology. With
these above normal PWATs, there is potential for locally heavy
rainfall. There is a marginal risk for flooding by the end of
the week with the multiple rounds of rain expected, especially
over areas with saturated ground from recent rainfall.

Widespread cloud cover and rain Thursday will limit potential
for severe thunderstorms, but instability is forecast to be
higher on Friday, so there are higher probabilities for
thunderstorms by Friday. However, it is too far out to
determine mesoscale details at this time, so confidence at this
time is lower on convective development by the end of the work
week.

Temperatures will be above normal, but clouds and rain will
moderate daytime temperatures through the period. Overnight lows
will be mild.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 130 PM EDT Tuesday...

Key Messages:

1. Continued chances for rain and possible storms.
2. Slightly cooler temperatures over the weekend, cooling to
below normal by midweek.

Through the Memorial Day weekend, a frontal boundary will
meander and stall over the eastern US, and an upper shortwave
tracks eastward from the central US, which will continue the
chances of unsettled weather through the period. While the
weekend doesn`t look to be a total washout, there are daily
chances of showers and thunderstorms each afternoon and evening.
However, differing model solutions on the progression, or lack
thereof, of the front, brings uncertainty and thus lower
confidence in the details on timing of the precipitation.

A 500mb trough moves towards the region during the first half
of the work week, and looks to deepen as the surface low moves
over the Great Lakes. As the upper flow transitions to more
northwesterly behind this system, temperatures will cool to near
to below normal by the middle of next week.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
As of 830 PM EDT Tuesday...

Expect VFR through the remainder of this evening, then
transition to patchy IFR to MVFR fog for the late night and
early morning Wednesday. Aside for the ground fog, the sky is
expected to remain mostly clear...surface winds near calm.

Daytime heating will lead to afternoon cumulus build-ups,
especially over the mountains where widely scattered showers and
thunderstorms are possible after 18z/2PM and continuing through
sunset.

Average confidence for cloud bases, wind, and visibility.


EXTENDED AVIATION OUTLOOK...

A cold front will approach the area Thursday bringing increasing
chance for showers and thunderstorms. 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.

&&

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

&&

$$

SYNOPSIS...NF
NEAR TERM...NF/PM
SHORT TERM...AS
LONG TERM...AS
AVIATION...PM