Chapel Hill, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

157
FXUS62 KRAH 181037
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
640 AM EDT Fri Jul 18 2025

.SYNOPSIS...
Deep high pressure will extend across the Carolinas through
Saturday. A series of upper level disturbances will track east and
southeast through the Mid Atlantic region through early next week,
as a backdoor cold front approaches from the north.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 220 AM Friday...

The mid-level anticyclone remains suppressed to our southeast this
morning.  A few weak mid-level perturbations continue to generate
showers and storms over the high terrain. However, this activity
should wane through the next few hours while central NC remains dry.

A stronger short-wave and associated mid-level perturbations
(currently over the Ohio Valley) will eject east across the Mid-
Atlantic this afternoon and evening. This will initiate scattered to
numerous showers along the Blue Ridge mountains which will move east
across the NC/VA Piedmont and Coastal Plain through tonight. There
remains both severe weather and hydro concerns with these storms,
which are detailed below.

Severe weather:  The latest 00Z HREF continues to pin the better
shear and storm organization (collection of mid-level helicity
swaths) up into central VA/Chesapeake area.  However, forecast
soundings still indicate a few concerning features for us: 1) high
DCAPE this afternoon and evening of ~1000 to 1200 J/kg and 2) ample
MLCAPE of 1500 to 2000 J/kg. As such, locally damaging wind gusts
will be possible with any stronger storms that develop today,
especially across the northern Piedmont/Coastal Plain.

Hydro concerns: Given the expected shear, a bit stronger cloud-layer
flow should promote faster moving storms compared to recent days.
However, latest CAMs suggest that a few waves of showers/storms may
be possible into the early overnight hours. If repeated areas are
hit, especially over urban areas, isolated flash flooding could
result. The best chances would appear to be north and east of
Raleigh as the latest HREF guidance pinpoints highest QPF up into
the Chesapeake region.

Heat: The Heat Advisory has been expanded to include the southern
Piedmont.  Heat Indices will peak in the 105 to 108 range this
afternoon especially for those south and east of the Triangle.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 220 AM Friday...

An upstream MCS/vort max will move across the Ohio Valley Saturday
afternoon and evening. This will once again initiate convection over
the mountains and along residual outflow boundaries from Friday`s
convection.  Should see scattered to numerous showers and storms
develop as a result.  Shear won`t be as good Saturday compared to
Friday and DCAPE will drop some as well (~600 to 800 J/kg).  As
such, think the severe risk will be lower compared to Friday.
However, can`t rule out localized wind damage from water-loaded
downbursts.   Additionally, weak cloud-layer flow will promote slow-
moving storms with ample moisture to tap into (PWAT ~2 inches). As
such, flash flooding will once again be a concern Saturday afternoon
and evening.

Temperatures will once again peak in the mid 90s Saturday afternoon
while dew points struggle to mix out of the 70s. As such, Heat Index
values will likely reach or exceed Heat Advisory criteria for
portions of our area (some uncertainty with residual cloudiness from
Friday`s convection).

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 305 AM Friday...

* Continued hot Sun, with heat index values as high as 105-109 from
  the Triangle to the S and E.

* Shower/storm chances more spotty Sun, then rebound higher Mon.

* Both heat and rain chances decrease for Tue-Thu.

This period starts out with the longwave pattern featuring a mid
level anticyclone centered over the Gulf coast and a faster NW
steering flow from the Midwest through VA/NC. This strong ridge
aloft is expected to then drift N over the lower Miss Valley and Mid
South by midweek, leading to a decrease and northward nudge of the
NW steering flow. This anticyclone will then hold roughly over S
IL/W KY/W TN while extending E across the Carolinas during the end
of the week, with above-normal heat likely to return by day 8/Fri.

Sun/Mon: While a series of perturbations is expected to track over
our region within a fairly swift (for this time of year) NW flow,
the predictability of such features is low. Models do suggest
overall that active convection Sat evening into the early overnight
hours will be associated with one particular shortwave that will
push E off the Mid Atlantic coast early Sun, resulting in a window
of weak height rises and perhaps a relative lull in convective
coverage Sun. Have kept pops Sun as scattered, close to
climatological pops, with modest QPF. Mon is then expected to be a
more active day with greater coverage of convection, as another
round of weak waves (which may have been induced by upstream Ohio
Valley MCSs) tracks ESE through our area. Streaks of heavier
rainfall and higher totals due to training may occur anywhere Mon
into Mon night. With a possible period of large scale neutral motion
or subsidence Sun and lower storm coverage, the heat should continue
with highs well into the 90s and heat indices aoa 105F across all
but the NW and central VA border area. By Mon, as a stronger
shortwave trough swings through the Northeast/New England and pushes
a surface backdoor cold front S toward NC, prefrontal moisture
pooling and mass convergence will support good chance to likely
pops. Temps should be about a category cooler Mon as compared to Sun.

Tue through Thu: Above normal shower/storm chances should persist
across our SW Tue, with slightly drier air working into our NE.
Then, as the strong ridge builds back eastward across NC with rising
heights and lowering lapse rates aloft along with a decreased
opportunity for Atlantic or Gulf moisture influx, shower/storm
chances should dwindle, restricted to just our far NW (terrain
storms easing E late in the day) and far SE (near the inland moving
sea breeze). Expect highs in the 80s to near 90 Tue/Wed and upper
80s to lower 90s Thu. -GIH

&&

.AVIATION /012Z FRIDAY THROUGH TUESDAY/...
As of 640 AM Friday...

VFR conditions are present across central NC at this hour, with
unrestricted vsbys and clouds that are mostly convective debris, a
few mid clouds and a veil of high thin clouds. The chances for any
sub-VFR conditions are low, a result of relatively dry air just off
the ground that is limiting the kind of stratus development we saw
Thu morning. And most high resolution guidance also shows a low
probability of sub-VFR conditions. Sct-bkn mid and high clouds will
hold into the afternoon, with bases aoa 5kft areawide, but do expect
a tempo period for TSRA starting early afternoon, especially across
the N (INT/GSO/RDU) before spreading E and SE (RWI/FAY) later in the
afternoon. Cigs/vsbys should drop to MVFR, and perhaps briefly IFR,
in and near any storms. The area should slowly trend dry overnight,
but expect lingering showers and isolated storms, especially near
RDU/RWI, overnight. As such, will need to keep a mention of cigs
flirting with MVFR, based 2500-3500 ft AGL, into the overnight hours
tonight. Surface winds will be from the SSW or SW at 6-10 kts
through this morning before shifting a bit to be from the SW or W
this afternoon into tonight at 8-12 kts.

Looking beyond 12z Sat, sub-VFR cigs/vsbys may linger into mid Sat
morning. Fairly high coverage of storms is again expected Sat
afternoon through Sat night, again highest across the northern
terminals, with early-morning sub-VFR fog/stratus possible.
Scattered to numerous showers and storms can be expected areawide
Sun and Mon with morning low clouds again possible, but then
coverage should drop for Tue through Thu, with sctd showers and
storms restricted to W and S areas. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM this morning to 8 PM EDT this evening for
NCZ008>011-024>028-040>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...Luchetti
LONG TERM...Hartfield
AVIATION...Hartfield