912
FXUS61 KRNK 181052
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
652 AM EDT Sat May 18 2024

.SYNOPSIS...
A nearly stationary front across northern North Carolina will
bring another round of showers and thunderstorms, with locally
heavy rain, across the area today. As this front drifts south
tonight, the chances of precipitation decrease with only
scattered mountain showers and storms expected Sunday. High
pressure will bring dry weather from Monday into most of
Wednesday, before an approaching cold front Thursday brings the
next chance of showers.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 240 AM EDT Saturday...

Key Message:

1) Around round of locally heavy rain and isolated severe storms
are possible in southern Virginia and northern North Carolina
today.

The 18/00Z RNK sounding showed an anomalously moist air mass in
place with a PWAT value of 1.29 inches which is above the 90th
percentile for this time of year. A weak upper level shortwave
seen on water vapor satellite lifting northeast across southern
WV combined with good isentropic lift north of the weak sfc
boundary to our south has kept widespread showers and isolated
storms over the area early this morning.

As this upper level wave continues to drift northeast away of
our area, widespread showers will gradually shift east and
diminish this morning. However, with the SREF indicating a good
chance (>70%) of SBCAPES exceeding 1000 j/kg in southern VA and
northern NC, combined with continued high PWAT values expected
to be >150% of normal in this same area, as well as increasing
upper level divergence this afternoon as the primary upper level
low across AK pushes east, confidence is high that another
round of showers and storms will develop in the early afternoon
hours.

The primary concern from these developing storms will be
localized flooding and flash flooding as forecast soundings show
a `long and skinny` CAPE which allows more time for the warm
rain processes to occur. In addition, many streams across
northern NC and southern VA are already running above normal as
shown from the National Stream Analysis Anomaly map. For now,
will let the current flood watch continue until 10 AM to account
for the current area of rain, but a new flood watch may need to
be issued shortly after this expires in our southern forecast
area.

The showers and storms, along with the threat for heavy rains
ends tonight as the low level boundary shifts south. Did not
deviate from the NBM for temperatures today and tonight.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
As of 220 AM EDT Saturday...

Key Messages:

1. Rain chances decrease through the day Sunday.
2. Warmer than normal temperatures expected Monday and Tuesday.

An upper level low will open into a trough as it drifts south into
North Carolina on Sunday. Bulk of the moisture and rainfall
associated with this system will also drift south and east of the
area starting Sunday morning. However, a surface trough may linger
over the mountains Sunday afternoon. Abundant low level moisture and
diurnal heating may help trigger a few thunderstorms in the
afternoon and evening. Sunday`s high temperatures will range from
the upper 60s to lower 70s

Surface high pressure will build over the region Sunday night into
Monday. Heights increase over the surface ridge Monday and Tuesday
helping to produce warmer than normal temperatures for the area.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As of 230 AM EDT Saturday...

Key Message:

1. Shower and storm chances return late in the week.
2. Temperatures warm into the 80s Wednesday and Thursday

A cold front is expected to track over the region Wednesday night
and stall over the area Thursday and Friday. This stalled boundary
will increase the chances for scattered showers and thunderstorms on
Thursday. A wave of low pressure will then move along this boundary,
bringing more storms to the area Friday. Yesterday 00Z models had a
cold front crossing the region on Wednesday with the rest of the
week dry. Since the latest 00Z models have a different scenario,
uncut guidance PoPs to chance Thursday and Friday due to low
confidence.

Warmer than normal temperatures are expected until the front moves
south of the area. Locations east of the Blue Ridge could have
temperatures in the mid to upper 80s to end the week.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
As of 650 AM EDT Saturday...

LIFR to MVFR conditions were observed at all TAF sties early
this morning. While some improvement to MVFR is expected for
most areas, and confidence is low, KLYH has the highest chance
of remaining at LIFR to IFR through the day Saturday.

Another round of rain and thunderstorms will be possible
Saturday afternoon, with highest confidence of storms being from
BCB to ROA and points south. If cigs improve to MVFR Saturday,
they quickly will drop to IFR at all sites by Saturday night.
While winds will generally be less than 10 knots, localized
strong wind gusts will be possible under and near storms
Saturday early afternoon into evening.

EXTENDED AVIATION OUTLOOK...

Showers and thunderstorms will slowly wane Saturday night, but
scattered storms re-develop, especially in the mountains on
Sunday. MVFR/IFR clouds and showers remain in the area for
Sunday and Sunday night.

Some improvements by Monday as the slow moving storm system
begins to depart east. Tuesday is the most likely day to be VFR.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Flood Watch until 10 AM EDT this morning for VAZ019-020-023-
     024-034-035-044>047-058-059.
NC...None.
WV...None.

&&

$$

SYNOPSIS...PH
NEAR TERM...PH
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...PH