279
FXUS62 KRAH 181352
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
952 AM EDT Sun Aug 18 2024

.SYNOPSIS...
An unseasonably strong upper and attendant cold front approaching
from the northwest will move gradually eastward through the region
today through Monday. A cooler and less humid air mass will settle
into the area from Monday night through Friday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 952 AM Sunday...

...There remains a slight risk (level 2 of 5) for severe storms from
Raleigh south and east this afternoon and evening...

...There is also a risk for Isolated Pockets of Heavy Rain and Flash
flooding along and east of US 1...

An unseasonably strong(~3 S.D. below normal)amplifying upper-level
trough will dig SEWD into the region through tonight and through the
day on Monday. At the surface, a pre-frontal sfc trough in the lee
of the Appalachians will get overtaken by an accompanying cold front
that`s currently making it`s way through central TN and KY. The cold
front is progged to move east across central NC during the evening
and overnight hours.

Not much has changed in the thinking of the forecast and severe
threat later today. There is bit more uncertainty wrt storm
coverage/PoPs, with latest model guidance potentially suggesting
that convective coverage may be a little more scattered in nature.
However, given the expected robust forcing, the near-storm
environment will be conducive to strong/severe updrafts.

Strong daytime heating, featuring afternoon highs in the mid/upper
80s north to lower 90s, will foster moderate to strong
destabilization area-wide, maximized over the Sandhills and southern
coastal plain. In advance of the cold front and coincident with core
of the stronger 40-50 meter H5 falls spreading into the area,
scattered showers and storms are expected to develop across the
western Piedmont between 18-21z. Thereafter, convection will have a
propensity to become better organized as the storms progress
eastward into the central Piedmont and western Sandhills between 20-
00z, and then across eastern Sandhills and coastal plain counties
between 23-04z. Deep layer shear of 30-35 kts will favor multi-
cellular severe threat, with damaging winds the primary threat. The
severe threat appears greatest between 4 to 10 pm.

Additionally, given recent wetness and with area streams and creeks
still running high, the convective downpours could also lead to some
instances of flash flooding, especially in poor-drainage and urban
areas.

Bulk of rain and convection will exit east of the area between at or
before midnight with mostly dry conditions thereafter. Areas of low
clouds/stratus are possible, mainly across coastal plain, INVOF the
cold front moving through the area. Lows ranging from mid 60s north
to lower 70s SE.  &&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 303 AM Sunday...

There is a marginal risk of severe storms in eastern NC on Monday
afternoon and early evening.

The main cold front will be moving through the eastern Piedmont to
the Coast during the day. However, the best heating and instability
is expected in the Coastal Plain into the Coastal Area where the
front will be moving through during peak heating. This region will
likely have the best chance of organized thunderstorms with some
local damaging wind gusts possible. Back over the Piedmont, the base
of the upper trough will swing through, but instability and surface
convergence will be lower than those that will exist down east. CAMS
suggest that there will be scattered thunderstorms with this
feature; however, these storms should be less robust. Highs will be
cooler and should range in the lower to mid 80s west and north, and
upper 80s SE.

Cooler and less humid air (a real break from typical August heat)
will arrive Monday night. Lows will dip into the upper 50s to lower
60s north and mid to upper 60s SE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 320 AM Sunday...

An unseasonably deep upper level trough will encompass most of the
eastern US Tuesday between strong ridges over the northern Atlantic
and southwestern US.  The strong shortwave digging through the
trough today and tomorrow will move east of NC by Tuesday, but it
appears there will be additional pieces of energy diving into the
back side of the trough to maintain the mean trough axis trough the
region through midweek.  However, with a 1024mb high shifting across
the Midwest and a notable airmass change Monday that results in
dewpoints falling into the 50s by Wed/Thu, the forecast is dry
through the end of the week.  Under the trough, 1000-850mb
thicknesses are forecast to drop into the 1370s and 1380s, 30m or so
below normal, resulting in highs as much as 5-10 degrees below
normal in the upper 70s to lower 80s by Thursday.  The lower
dewpoints will also support overnight lows in the mid and upper 50s
in many locales.  The cool down will be relatively short lived
however, as the upper ridge over the SW US is forecast to build east
across the Deep South by next weekend and highs will trend back
toward normal.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
As of 633 AM Sunday...

Generally VFR conditions with some higher cloudiness can be expected
through 18z today. The exception will be between 09z and 13z in
which some stratus (IFR) is expected. Scattered thunderstorms are
expected this afternoon and evening, with brief IFR conditions
possible.

Looking beyond 00z Mon, Some lingering storms are expected through
04z/Monday. Otherwise, stratus is possible again around daybreak
Monday. Another round of scattered storms is possible at all sites,
but mainly RWI/FAY, Monday afternoon. VFR conditions should return
Mon night and prevail, with high confidence, through Thu.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Badgett/CBL
NEAR TERM...CBL
SHORT TERM...Badgett
LONG TERM...BLS
AVIATION...Badgett