774
FXUS62 KRAH 081326
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
925 AM EDT Mon Jul 8 2024

.SYNOPSIS...
A weak frontal zone extending from Chesapeake Bay through central
North Carolina will weaken further today before dissipating tonight.
Mid and upper level high pressure will build over the area through
mid week, before another cold front approaches Wednesday night. This
front will then stall out and hold over the western and central
Carolinas through Friday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 925 AM Monday...

Water vapor imagery this morning depicted narrow mid-level ridging
along the eastern seaboard. To our east, a mid-upper low continues
to spiral off the Carolina coast. This low will remain quasi-
stationary and offshore today, thanks in part to a slowly meandering
MCV currently over our southern Piedmont this morning.  This feature
will slowly ooze eastward today across the Sandhills/central
Piedmont, before weakening and diving to our south through early
Tuesday morning.

At the sfc, a weak boundary was observed extending from the mouth of
Chesapeake Bay ssw through our central to southern Piedmont. This
feature will migrate westward today before dissipating through
tonight.  While CAMs continue to suggest less coverage today
compared to recent days, given the presence of this decaying sfc
boundary, and the slow moving mid-level impulse, still think we`ll
see some development of showers and a few isolated storms later this
morning through this evening.  Think that we`ll see greatest
coverage over the southern/western Piedmont, as well as some better
coverage perhaps in the southern Coastal Plain as sea-breeze induced
convection penetrates inland later this morning. H8/H9 flow is
relatively onshore wrt to the coast, and thus any sea breeze
convection that develops should be able to penetrate inland pretty
good today.

Lapse rates and shear are pitiful today, and thus severe storms
don`t appear likely.  However, given how water loaded this
atmosphere is, can`t rule out an isolated stronger gust with any
deeper pulse storms. Best chance would appear to be in the southern
Coastal Plain, where low-level lapse rates may steepen a bit more
compared to areas north and west. But even there, the probability
seems low.  However, given weak steering flow, isolated flooding
will be possible today with any heavier showers/storms.

Given some cloud cover expected today, temperatures should max out
in the upper 80s/lower 90s, with heat indices remaining below
advisory criteria. Overnight lows will remain warm in the mid 70s,
with some patchy fog possible especially across southern areas.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 300 AM Monday...

Very little changes with our weather pattern, and again expect
convective coverage to peak at scattered, focused across our west
sections and southeast. The narrow mid-upper level ridge continues
to build across central NC, while a diffuse MSLP pattern with weak
surface winds and continued dewpoints mostly in the 70s will
contribute to a weak wind profile through the column and, once
again, slow-moving and outflow-driven convective clusters that could
drop isolated heavy rain. With higher res models like the RAP and
HREF members showing lower storm coverage and an earlier demise than
what we`ve seen the last couple of days, the resulting reduction in
convective debris clouds that might hinder heating combined with
thicknesses about 5-8 m above normal suggests that we`ll see temps a
bit warmer than today. Expect highs in the low-mid 90s which will
push HeatRisk into the high-end Moderate and low-end Major
categories. Lows will again be mostly in the 70s. -GIH

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 308 AM Monday...

* Typical summertime pattern through the extended with high humidity
* Hottest temperatures Wed/Sun and lowest highs Fri
* Highest shower/storm chances Thu into Sat

The remnants of Beryl, after interacting with a mid-level shortwave
trough over the Great Lakes and Midwest, will be located somewhere
near IL/IN by early Wed. Little has changed with its overall track,
with most ensemble and deterministic solutions taking this area of
low pressure ENE into the Great Lakes and Canada by Thu/Fri. The
system will bring a cold front near the area late Wed night to early
Thu across the western NC mountains and then is still forecast to
stall along or just west of the area into Sat.

With the front not approaching until late Wed across the west, we
will have another day of hot and humid conditions midweek as
southerly flow remains well entrenched, if not more so. Heat indices
could meet or exceed 105 in portions of the Triangle and Sandhills,
with highs in the low to mid 90s and dewpoints near the low to mid
70s. Scattered showers and storms appear favored in the aftn/eve,
especially across the west with the approaching front and pre-
frontal trough.

As the front gets hung up and stalls along or just west of the
Piedmont Thu, guidance continues to show an area of low pressure
forming along the SE US and riding up along the boundary through
central/eastern NC late Thu into early Sat. This area of low
pressure could be convectively induced as an MCV and/or through some
interaction with an upper-level shortwave tracking toward the
Carolinas from the western Atlantic. Either way, during this time,
there continues to be deep moisture transport and anomalous PWATs of
2.1-2.3 inches (normals are about 1.4-1.5 in) to couple to the low-
level frontal/trough convergence. WPC is currently placing our area
in a Level 1 out of 4 risk of excessive rainfall for Fri/Sat and
this is quite reasonable given the mentioned factors. This will
continue to be monitored as we get closer. As such, our highest rain
chances still appear to be Thu into Sat.

By the weekend, we will see more typical diurnal shower/storm
chances, though somewhat drier conditions should take hold by Sun as
WSW flow ensues with a trough axis building in from the west and
ridging off the western Atlantic reasserting itself. A more typical
lee trough looks to take over at the surface, with PoPs more toward
climo.

Temperature wise after Wed, highs trend to the 80s on Fri,
coincident with highest rain chances. A return to the 90s, and
consequently heat indices above 100, look in store Sat/Sun as the
ridge builds back west with lesser rain chances.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
As of 610 AM Monday...

The MVFR to IFR stratus developed overnight as expected, but apart
from a few periods of low cigs at INT/GSO earlier this morning, the
most persistent sub-VFR conditions have held just outside of the
Piedmont TAF sites of INT/GSO/RDU. Nevertheless, some of these low
clouds may still drift near these terminals in the next few hours
before the clouds begin to slowly lift and break up through mid
morning. Will maintain a low-confidence tempo period for these
possible brief cigs at INT/GSO/RDU, with nothing at RWI/FAY. Much of
the residual isolated light rain patches across the W and S Piedmont
from earlier this morning have fizzled, but a few spots of light
rain do remain. All central NC TAF sites are likely to be VFR by 16z-
17z. Scattered showers and storms are expected today, forming first
through the central sections of central NC (including RDU) late
morning/early afternoon, then over the NW and SE areas (INT/GSO and
FAY) mid afternoon through early evening, with storms likely to
develop over the higher terrain and drift into the Triad, and along
an inland-moving sea breeze toward FAY. Periods of sub-VFR
cigs/vsbys and gusty/erratic winds are possible in and near any
storms today. Overall coverage is expected to be lower than over the
last two days, and showers and storms should start to decrease and
diminish by mid to late evening. There is a chance for sub-VFR
cigs/vsbys early Tue morning, mainly across the S, but should be
less coverage than this morning. Outside of any storms today into
tonight, surface winds will be light and variable, mainly from the S
(SE through SW).

Looking beyond 12z Tue, a general pattern of scattered to numerous
showers and storms primarily each afternoon through evening will
continue through Fri, with the highest chances late Wed night
through Fri, and at least some chance of early-morning sub-VFR
clouds/fog each day. -GIH

&&

.CLIMATE...

Record High Temperatures:

July 10:
KRDU: 99/1993

Record High Minimum Temperatures:

July 8:
KGSO: 76/2010
KRDU: 78/1986
KFAY: 79/2012

July 9:
KGSO: 76/1987
KRDU: 74/2014

July 10:
KGSO: 77/1981
KRDU: 77/1981
KFAY: 77/1998

July 11:
KGSO: 75/1992
KRDU: 77/1981
KFAY: 76/2019

July 12:
KGSO: 76/2011
KRDU: 78/2011
KFAY: 80/1935

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...Hartfield
LONG TERM...Kren
AVIATION...Hartfield
CLIMATE...RAH