278
FXUS62 KRAH 080709
AFDRAH

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

.SYNOPSIS...
A weak frontal zone extending from Chesapeake Bay through the
Piedmont of the Carolinas will weaken further today before
dissipating tonight. Mid and upper level high pressure will build
across 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 205 AM Monday...

Continued partly to mostly cloudy and humid but with slightly lower
convection coverage expected today.

The degree and extent of morning cloudiness will play a role in the
initiation of showers/storms today. An MCV and persistent widespread
rain with embedded storms covering much of central SC has scraped
across our SW areas, bringing locally heavy rain to Anson county in
the last couple of hours, although cloud tops with this feature
continue to warm steadily as it drifts ESE. This MCV appears to be
locked to a very weak and diffuse frontal zone stretching over the
Carolina Piedmont, and this front should continue to weaken today. A
very moist column persists over our area, with PWs in the 2-2.5"
range, 150%-175% of normal, although the highest values are expected
to push slightly NW to be situated more over the NW Piedmont, nudged
by the upper low off the Carolina coast tracking to the SSW toward
the N Bahamas. Narrow mid-upper level ridging will build today from
the central FL panhandle NE through central NC, which will keep our
mid level flow and steering very weak, thus slow and meandering
outflow-steered convective cells/clusters may produce a localized
mostly nuisance flooding risk once again today. The presence of
nocturnal stratus well into the morning and abundant debris mid and
high clouds in tandem with slightly warmer mid levels should cut
back on SBCAPE a bit today, too, which with poor deep layer shear
should hinder storm organization. Will have scattered showers and
isolated storms through this morning, with pops then rising to good
chance in the afternoon, highest in the W and SE (the latter likely
focused on old boundaries and sea breezes). Expect pops to again
decrease in the evening, although given the potential for another
round of MCVs and warm/moist low levels to keep some amount of
marginal elevated CAPE going well past sunset, confidence in a dry
overnight is pretty low. Expect highs in the upper 80s to mid 90s,
followed by lows in the 70s. -GIH

&&

.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 /06Z MONDAY THROUGH FRIDAY/...
As of 1230 AM Monday...

Confidence is high in widespread sub-VFR stratus (mostly IFR/LIFR)
and areas of mostly MVFR fog persisting across much of central NC
until mid morning, particularly affecting INT/GSO/RDU, with slightly
lower confidence at RWI/FAY. Patchy rain will dwindle but linger
over the far SW edges of the forecast area through daybreak, however
much of the area will stay dry through mid morning. IFR clouds will
be slow to improve, likely rising to MVFR between 14z and 16z
(slowest in the W Piedmont) and to VFR by 18z. FAY is likely to see
MVFR/IFR cigs lasting a shorter time, 10z-14z, with 08z-14z at RWI.
Scattered showers and storms are expected today, through the central
sections (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. 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. Periods of sub-VFR cigs/vsbys and gusty/erratic winds
are possible in and near any storms today. Outside of any storms
today/tonight, surface winds will be light and variable, mainly from
the S (SE through SW).

Looking beyond 06z Tue, there is a chance for sub-VFR cigs/vsbys
early Tue morning, mainly across the S, but should be less coverage
than this morning. 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...Hartfield
SHORT TERM...Hartfield
LONG TERM...Kren
AVIATION...Hartfield
CLIMATE...RAH