Morrisville, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

116
FXUS62 KRAH 110757
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
357 AM EDT Fri Jul 11 2025

.SYNOPSIS...
Upper level disturbances will pass over the Mid Atlantic and
Carolinas through the weekend, as a warm and humid air mass holds in
place.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 320 AM Friday...

* Significantly less convective coverage expected today compared to
  the past several days.

* Hot and humid today with heat indices back into the mid 90s to low
  100s.

In between the departing detached shortwave over the eastern
Carolinas and trough shifting through the central Plains, H5 heights
will subtly rise over the southern Mid-Atlantic (around 20m in
12hrs) through the daylight hours. Additionally, the brief
northwesterly flow aloft will help shift the seasonably anomalous
deep-layer moisture, which has plagued central NC since TS Chantal,
will finally shift out into the western Atlantic. These two shifts
in the synoptic pattern will result in significantly less convective
coverage over central NC compared to the past several days with most
locations expected to remain dry today.

Although the mid/upper levels of the thermodynamic and synoptic
environment will be different, the surface airmass will remain
unchanged as southwesterly to southerly surface flow will prevail.
This will result in a still warm and humid afternoon. Surface dew
points in the low/mid 70s should also result in 1000-2000 J/kg of
MLCAPE with diurnal heating. Poor lapse rates through the thermo-
profile and rising mid-level heights will make convective
development and maintenance difficult, but not impossible, over a
majority of central NC. The primary exception will likely be across
the Foothills into the western Piedmont of NC where terrain
circulations and steeper low-level lapse rates should initiate
convection by early afternoon. This activity may slowly drift
southeastward into central NC by the middle to late afternoon.

Although most locations will remain dry, the 00z HREF and 18z REFS
are in good agreement that a couple extremely isolated slow moving
showers may still produce a quick 1 to 2.5 inches of rainfall. If
this were to occur over the still vulnerable locations of the
Piedmont (Winston-Salem to Roxboro to Fayetteville to Rockingham to
Lexington) or directly over an urban area, isolated flash flooding
may still be possible. High temperatures will range from the upper
80s to low 90s with heat indices in the mid 90s to low 100s.
Overnight lows will remain seasonably mild in the low/mid 70s.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 355 AM Friday...

Saturday will again feature W/NW mid-level flow across the region,
with a ridge building from the Gulf up the Eastern Seaboard, and
weak shortwave troughing east of the NC coast. At the surface, a
weak lee trough will be in place, with a stationary area of low
pressure off the Mid-Atlantic coast. While PW values will again be
somewhat drier compared to previous days and similar to what we are
expecting today (1.5 to 2 inches), a warm and moist air mass will
still be in place in the low levels, with surface dew points in the
70s. So moderate destabilization is again expected, with SBCAPE in
the 1500-3000 J/kg range.

Thus there is a threat of showers and storms across central NC once
again on Saturday afternoon and evening. However, average rainfall
amounts on the global models are fairly low, only around a tenth to
a quarter inch, which signals more modest convective coverage. This
is also backed up by the CAMS, which differ on coverage and
intensity of convection, but LPMM on the 00z HREF and 18z REFS
depicts only isolated localized pockets of 1-3+ inches, with most
areas receiving far less if anything. Am also skeptical of how much
coverage there will be given the ridging aloft and weak mid-level
height rises that will be in place. So POPs are only in the chance
(generally 30-40%) range. Still, given how saturated the ground is
from this week`s rainfall, it won`t take a lot to cause renewed
isolated flooding concerns, and the WPC has a marginal (level 1 of
4) risk of excessive rainfall across all of central NC for Saturday.
The greatest risk appears to be in the south where the best deep-
layer moisture will be, which is also where the greatest HREF
neighborhood probabilities of exceeding 3 inches are. But with how
much rainfall the Piedmont has received lately, the threat exists
anywhere. Can`t rule out gusty winds with any storms either, and wet
soils mean even sub-severe winds could still knock down some trees.

Saturday`s forecast highs are in the lower-to-mid-90s, with heat
indices in the low-100s possible from the Triangle south and east.
Convection will diminish on Saturday night with loss of daytime
heating. Lows will be in the lower-to-mid-70s.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 355 AM Friday...

The weak shortwave and surface low off the Mid-Atlantic coast will
weaken and lift farther NE on Sunday. Meanwhile the mid-level
ridging over the Southeast US will begin to get suppressed a bit by
an incoming trough that moves east across the Great Lakes region.
This may result in slightly better shower/storm coverage across
central NC on Sunday, a trend that continues into Monday as the
trough moves across the Northeast US and Mid-Atlantic and drags a
cold front that may approach us from the west. PW values in guidance
also increase slightly, to the 2-2.25 inch range. So WPC has much of
our region in a marginal (level 1 of 4) risk for excessive rainfall
on Monday, though the best mid/upper forcing from the trough looks
to be to our north. Highs will generally be in the upper-80s to
lower-90s (near to a few degrees above normal) with mild lows in the
lower-to-mid-70s. Heat indices in the low-100s will be possible in
the south and east.

The trough will then move to the east with very weak mid-level flow
continuing from Tuesday through Thursday. It remains likely that the
front fizzles out by the time it gets here, so there will be little
if any air mass change through the period, with warm and humid
conditions persisting. Thus as is typical this time of year for
central NC, our precipitation chances will largely rely on daytime
heating and convection, maximized each afternoon and evening. POPs
do remain above climo as the Bermuda High will gradually extend
further west through the week, helping keep southerly low-level flow
that pumps in plenty of moisture to the region, with surface dew
points remaining in the 70s. High temperatures may decrease a bit to
mid-80s to 90, but this will still be enough for moderate
destabilization each day. Given how wet it has been lately, any
storms could result in locally heavy rainfall and flooding. Weak
shear should continue to preclude an organized severe threat. Lows
will stay above normal, mainly in the lower-to-mid-70s, given the
humid air mass in place.

&&

.AVIATION /0720Z FRIDAY THROUGH TUESDAY/...
As of 320 AM Friday...

As the trailing stratiform rain continues to dissipate, IFR to
LIFR cigs and MVFR to IFR vsbys are expected to fill in at FAY,
RWI, and eventually RDU. At the Triad terminals, SCT to BKN
LIFR cigs have developed and will likely persist for at least a
few hours. Some scattering is possible through early morning,
but confidence is low. Gradual improvement to VFR is expected
through the morning hours at all TAF sites. Coverage of
showers/storms this afternoon/evening appears to be much less
than previous days. Probabilities for terminal impacts from
convection is 10 to 25% and precludes the addition for PROB30s
in the 06z TAFs at this time (best times will be anywhere
between 17z and 23z).

Looking beyond 06z Sat, the overall pattern will remain largely
unchanged into early next week, with a risk for early-morning
sub- VFR fog/stratus, and a chance for showers and storms each
afternoon into the evening.

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Swiggett
SHORT TERM...Danco
LONG TERM...Danco
AVIATION...Swiggett/Hartfield