116
FXUS62 KRAH 282353
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
753 PM EDT Fri Jun 28 2024

.SYNOPSIS...
High pressure will move off the New England coast tonight. A hotter
and more humid airmass will become established across the area this
weekend. A cold front will approach the area Sunday bringing the
next chance of storms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 753 PM Friday...

Evening analysis shows a stalled boundary across northern sections
of SC and arcing into eastern TN. High pressure was situated off the
New England coast. The high will shift off into the north Atlantic,
resulting in a developing southerly flow toward sunrise Sat. With
the more moist flow off the southwest Atlantic, dewpoints will
likely rise overnight after mixing out earlier this afternoon.
Daytime convection along the sea-breeze brought isolated storms
across Sampson Co and the Sandhills. The convection has produced a
well pronounced outflow evident on radar, currently pushing into
Moore, Lee, and Chatham counties. As this outflow continues to track
WNW through the late evening, high-res CAMs such as the HRRR show
spotty isolated activity developing over the western/southern
Piedmont and perhaps over the Triad. Any storm activity should
weaken after midnight with loss of heating and forcing, though
cannot rule out a stray shower over the Triad near daybreak.
Overnight lows should be in the upper 60s to low/mid 70s. Guidance
is hinting at some widespread low stratus and possibly patchy fog
with the onshore flow taking shape overnight into daybreak Sat. This
should lift and dissipate by mid-morning.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 415 PM Friday...

Hot, seasonably humid, with a small chance of showers/storms on the
wrn and ern flanks of cntl NC.

Cntl NC will remain tucked between a couple of sub-tropical to lower
mid-latitude mid-level highs/ridges centered over the srn Plains and
w-cntl Atlantic, respectively. Poleward of this expansive zone of
ridging, a compact mid-level cyclone now over nern MT will become an
open wave trough while pivoting across the nrn Plains and upr MS
Valley through 12Z Sat, then accelerate newd and across the Great
lakes and QC through 12Z Sun. A trailing shortwave perturbation now
over the cntl Canadian Prairies will dig sewd into the upr MS Valley
and upr Great Lakes Sat and then follow a similar path as the first
shortwave trough through Sun. In the intervening swly flow between
these shortwave perturbations and the aforementioned ridges, a
convectively-amplified mid-level trough will move across the OH
Valley and cntl Appalachians Sat and the Middle Atlantic Sat night,
the latter when weak mid-level height falls (10-20 m/12hr) will
glance the srn Middle Atlantic. Weak mid-level lapse rates of less
than 5 C/km will exist over cntl NC on Sat, with a slight increase
to between 5-5.5 C/km, amid the aforementioned weakly falling
heights, Sat night.

At the surface, the remnants of a couple of fronts that have settled
across the South Atlantic states during the past 24 hours will
retreat nwd across the Middle Atlantic, on the wrn periphery of high
pressure over the Atlantic basin. Broad sly flow will result
throughout the South and Middle Atlantic states, while a lee trough
will develop with diurnal heating over the srn Middle Atlantic and
Carolina Foothills/wrn Piedmont. Weak confluence between the
Atlantic high and lee trough will result over the Foothills and wrn
Piedmont. A sea breeze will also retreat inland and across ern and e-
cntl NC through the evening.

While both temperatures and humidity levels will be on the increase
as a result of the return to sly flow and the influence of the
ridging aloft, afternoon/mixed surface dewpoints are likely to
decrease into the upr 60s to around 70 F. Resultant heat index
values, when factoring in high temperatures mostly 92-98 F, are
likely to peak in the 100-105 F range over all but the nrn and nwrn
Piedmont, where upr 90s will be common. Those mixed dewpoints will
also result in a minimum of MLCAPE generally between 500-1000 J/KG
over cntl NC, with slightly higher dewpoints in the lwr 70s, and
MLCAPE between 1000-1500 J/KG, along and west of the Yadkin Valley
and from the the far ern Coastal Plain to the coast. A 20-30 percent
chance of showers/storms will consequently exist along the wrn/ern
flanks of cntl NC. Overall coverage and strength of convection will
be limited by the relative lack of buoyancy and forcing for ascent,
aside from low-level convergence along the sea breeze and into the
lee trough.

After a lingering small chance of showers/storms over the srn/wrn
Piedmont during the evening, it will otherwise be warm and muggy
overnight, with lows 75-80 F.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 255 PM Friday...

Hot and stormy Sun/Sun night, then generally quiet and mostly dry
through the work week. Near normal temps Mon-Tue will once again
give way to intensifying heat for July 4th and into the weekend.

Sun-Sun night: Expect hot and muggy conditions with high rain
chances as a potent mid level trough deepens with a positively tilt
as it shifts through far SE Canada/St Lawrence Valley into the
Northeast states. Just ahead of this trough axis and its associated
surface front, anomalously high PWs near 2.5" will spread in
areawide, with mid level moistening and cooling resulting in an
erosion of mid level stability, as steepening lapse rates through
the column and prefrontal afternoon heating push SBCAPE to 1000-2500
J/kg, according to the latest LREF. Mid level flow and deep layer
bulk shear will remain somewhat muted much of the day, however,
peaking at just 15-25 kts, highest near the border Sun evening/night
as the stronger cyclonic flow aloft dips into our latitude with
trough axis passage. This will also result in the better upper
divergence holding off until after dark, and this lack of temporal
juxtapositioning of buoyancy and dynamic forcing for ascent could
limit our severe threat. But given the forecast SBCAPE and deep
mixing with elevated DCAPE, the threat of a few strong wet
microbursts seems realistic. Will continue with high pops, peaking
at likely at some point over the entire CWA. Sun is likely to be
another day of dangerous heat, with very warm morning temps and
highs mostly in the mid 90s, giving heat indices again around 100-
105 over most of the area. The surface front should drop slowly SE
through the area (more likely, jumping into a prefrontal trough or
convective outflow) Sun night, with some lower dewpoints expected to
start arriving into the north sections overnight. Lows in the upper
60s to mid 70s.

Mon-Fri: The front and deep moisture may still be lingering across
southern sections Mon morning, so will maintain good chance to low
likely pops there early. But as the front settles to our S and drier
air works in from the N amid briefly gusty NE winds Mon, and within
ridging both at the surface and aloft, expect a trend to no pops
late Mon, lasting through mid week as high pressure noses in from
the N. Expect temps to be near to even slightly below normal
Mon/Tue, with dewpoints in the 50s and 60s, making it feel quite
pleasant. Then, as the mid level trough extending down through the
Mid Atlantic early Mon shifts offshore and ridging builds further
from the S Plains/Lower Miss Valley into the Carolinas, with the
surface ridge pushing out over the open NW Atlantic, rising humidity
and thicknesses will bring a return to oppressive heat. Highs should
be in the low to mid 90s Wed and mid 90s to near 100 on July 4th and
Fri, as thicknesses climb to nearly 20 m above normal. With mid
level warm/stable air beneath the strong ridge aloft and limited
deep moisture flux into the area, rain chances will remain low Wed,
then will have a trend toward climo pops for Thu/Fri, just 25-35%
chance at most with those higher values focused on the extreme NW
where mountain convection could drift late each day. -GIH

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
As of 703 PM Friday...

VFR conditions will prevail to start the TAF period. However, MVFR
to IFR stratus is likely to develop at all terminals late
tonight/early Saturday morning. Otherwise, a few isolated showers
could reach KINT/KGSO this evening, but overall the forecast appears
mostly dry tonight.

Any lingering stratus should lift to VFR by late morning/early
afternoon. After which, a few isolated showers/storms could impact
KINT/KGSO tomorrow afternoon. However, coverage looks limited and
mostly confined to the mountains.

Outlook: Sub VFR conditions will be possible area wide Sun morning
with IFR stratus, followed by a good chance of mainly afternoon-
evening showers/storms Sunday. VFR conditions are expected early to
mid week next week.

&&

.CLIMATE...

Record High Temperatures:

June 30:
KFAY: 102/2012

July 4:
KGSO: 98/1970
KRDU: 101/2012
KFAY: 98/2019


Record High Minimum Temperatures:

June 28:
KRDU: 76/1952
KFAY: 78/1914

June 29:
KGSO: 74/2010
KRDU: 78/1914
KFAY: 76/1969

June 30:
KGSO: 74/1936
KRDU: 80/1936
KFAY: 79/1936

July 1:
KRDU: 75/2012
KFAY: 76/1990

July 4:
KGSO: 73/2018
KRDU: 79/1902
KFAY: 78/1913



&&

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

&&

$$
SYNOPSIS...CA
NEAR TERM...Kren
SHORT TERM...MWS
LONG TERM...Hartfield
AVIATION...Luchetti/CA
CLIMATE...RAH