164
FXUS62 KRAH 041830
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
230 PM EDT Thu Jul 4 2024

.SYNOPSIS...
Surface high pressure will extend across the western Atlantic and
Deep South through tonight and then weaken and shift east on Friday.
A cold front will approach the region from the northwest late Friday
and then move into the Carolinas during the weekend.
&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 1045 AM Thursday...

* Hot and humid conditions will return this afternoon.
* Scattered thunderstorms will drift into north-central NC this
  afternoon and move into the NC Piedmont this evening as they weaken.
* Storms will be efficient in producing strong gusty winds.

The morning surface analysis shows high pressure centered across the
western Atlantic extending west into the eastern Carolinas and the
eastern Gulf of Mexico. A cold front extends from the eastern Great
Lakes southwest across the western OH Valley and into the MO Valley.
A weak lee trough is noted across central VA and NC. Further aloft
an anomalously strong west to east 500mb ridge was centered across
the Deep South. The main belt of westerlies extend from a trough
across across western KS/NE and into the Great Lakes.

The air mass across central NC this morning is warm and relatively
moist with PW values of 1.6 to 1.8 inches or around 110% of normal.
Morning low level thickness values ranged from about 1410 to 1420m,
with the greatest thickness values extending south to north across
the western Piedmont of the Carolinas. KGSO observed a thickness
values of 1418m this morning, that`s 25m greater than yesterday at
12Z.

Regional radar imagery shows a few clusters of showers and storms
moving across eastern KY and southern WV early this morning. This
convection is supported by a series of disturbances around the
periphery of the upper level ridge including a couple of MCVs from
overnight convection. The latest visible satellite imagery shows
mainly clear skies across central NC with some enhanced cumulus
clouds in the NC mountains and cloudiness across KY/WV associated
with the convection.

The upper level ridge will relax a bit today allowing the train of
disturbances across the TN Valley to take a slightly more southern
trajectory into southern VA and perhaps northern NC this afternoon
and evening. With a slightly weaker ridge, mid-level lapse rates
will steepen slightly and strong diurnal heating combined with
dewpoints in the upper 60s to lower 70s will result in moderately
unstable airmass this afternoon with MLCAPE values ranging around
1500 J/kg. Isolated convection may develop late this afternoon near
the lee trough with slightly better convective coverage likely
across southern VA in the stream of disturbances aloft that will be
aided by differential heating, the lee trough, and outflow from
ongoing convection to the north. This area of widely scattered
convection will shift south and east into northern NC late this
afternoon and into the Piedmont this evening as it weakens. Recent
high res guidance suggest a downward trend in coverage from last
nights guidance, especially during the evening, focusing rain
chances in the Triad and near the VA border counties. With strong
heating today and deep boundary layer mixing, inverted-V
thermodynamic profiles are expected supporting DCAPE values well in
excess of 1000 and likely resulting in efficient production of
strong gusty winds with convection. With limited forcing for ascent,
expect the convection to wane during the mid evening and would be
surprised if much if any rain makes it south of KRDU or KRWI with
all of the convection dissipating by midnight.

With a hotter airmass and low level thickness values 25m higher than
yesterday in many locations, highs today will range between 6 and 9
degrees hotter than on Wednesday and range in the mid 90s to around
100. Expect highs to reach daily records at RDU and FAY. With
boundary layer mixing, dewpoints will mix out a bit this afternoon
and temper heat index values that will range in the upper 90s to
lower 100s in most locations with a few spots including KRDU, KFAY
and KGSB flirting with 105F.

Skies will be partly cloudy overnight with a mix of some patchy high
clouds and perhaps some patchy stratus or low clouds across the
south and southeast. It will remain warm and muggy tonight, with
lows mainly in the mid 70s. -Blaes

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
As of 230 PM Thursday...

* Heat Advisory is in effect for Friday.

Additional details coming soon.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 226 PM Thursday...

Saturday may offer an opportunity for above-climo PoPs with
scattered showers/tstms as a prefrontal trough moves into our area
ahead of an upper s/w trough moving NE across the eastern Great
Lakes region.  The rain will be welcome due to recent dryness, but
also to limit the intensity of the daytime heating, particularly
across our western and Triad zones where rain will arrive earlier in
the afternoon.  There, highs in the lower 90s...vs upper 90s east
where rain will arrive later in the day.

The aforementioned trough will weaken and stall Saturday night with
a broad pressure trough lingering over the Piedmont for Sunday. This
pattern will yield another round of afternoon/evening scattered
showers/tstms with highs a bit lower than prev days (in the lower
90s) given the anticipated cloud cover and scattered showers/tstms.

Next week`s pattern will be very near climo, both daily PoPs and
daytime high temps, given an active daytime Piedmont trough which
will result in scattered showers/tstms each afternoon and evening
and resulting clouds, rain, and outflows which will keep temps in-
check near, or just above climo values.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
As of 230 PM Thursday...

Widely scattered thunderstorms will drop southeast from the NC
mountains and southern VA and move into the northwest Piedmont,
Triad area and VA border counties affecting the KINT and KGSO
terminals between 19 and 00Z. A wind gust to near 35kts and a brief
MVFR restriction mainly for visibility is expected with the stronger
storms. These storms will weaken as they near the KRDU and KRWI
terminals between 22 and 02Z with the precipitation dissipating
before reaching KFAY. Otherwise, VFR conditions are expected tonight
and into early Friday afternoon. Southwest to westerly winds at 6 to
10kts are expected this evening with light southerly winds tonight
into early Friday.

Outlook: There`s a chance of late afternoon and evening
thunderstorms on Friday with a slightly better chance of showers and
thunderstorms Saturday into Tuesday as cold front drops into the
region and stalls across the area. In addition, some late night and
early morning fog and stratus is possible on Saturday and
especially Sunday and Monday mornings. -Blaes
&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 8 PM EDT Friday for NCZ007>011-
021>028-038>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Swiggett
LONG TERM...NP
AVIATION...Blaes