305
FXUS62 KRAH 170833
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
435 AM EDT Thu Jul 17 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 from Saturday night
through Monday, as a backdoor cold front approaches from the north.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 138 AM Thursday...

Water vapor imagery this morning depicted the western ridge of the
offshore, mid-level high firmly inland over the deep south. Here
locally, wswly flow was evident over central NC.

While there is some lingering convection along the Appalachians,
this activity should wane through the night and dissipate before
reaching us. Dry conditions should persist this morning, but expect
isolated to scattered convection to develop this afternoon and
evening first over the mountains/foothills before trickling across
our western and northern Piedmont. A secondary focus for convection
will be along the inland penetrating sea breeze in our Coastal Plain
locations.  Overall, the coverage should be similar to yesterday, as
some "drier" wly flow in the lower levels will limit widespread
convection.  The mean cloud-layer flow is weak again (~10 kts), and
as such expect 1) pulse storms and 2) slow-moving storms. As such,
can`t rule out an isolated damaging wind gust and/or isolated flash
flooding in urban areas (especially the Triad where recent runs of
the HRRR indicate some better rain rates somewhere in the Triad/Mt.
Airy vicinity). Convection should largely wane with loss of heating
this evening.

Temperature wise, expect highs today to reach the upper 80s to lower
90s. While dew points will only mix out into the lower 70s this
afternoon, heat indices should only peak around 100 or so, and thus
remain under Heat Advisory criteria.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 138 AM Thursday...

Temperatures will increase some on Friday, with most guidance in
good agreement for highs to reach the mid 90s. Dew points will
struggle to mix out, and as such we may reach Heat Advisory criteria
over portions of our CWA. Best chances would be from Raleigh ->
south and east.

Convection wise, models are hinting at a bit stronger short-wave
moving across the Mid-Atlantic Friday afternoon and evening. This
will likely trigger widespread convection along the Blue Ridge
Mountains which will then propagate across the VA/NC Piedmont. The
HREF is depicting ~30 to 35 kts of shear across the Mid-
Atlantic/Chesapeake vicinity. While shear looks to be weaker with
southward extent, the HREF depicts 20 to 25 kts of shear potential
across the NC/VA border. As such, a few storms could be strong to
severe with damaging wind being the biggest potential hazard. It`s
worth noting that the AI/ML guidance also have relatively higher
probabilities over our northern areas for severe weather potential.
So while the shear looks modest at best, there is a signal there in
the guidance worth keeping a close eye on.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 245 AM Thursday...

* Continued hot Sat, with heat index values as high as 105-108
  possible from the Triangle to the S/E.

* High rain chances Sat/Sat night with heavy rainfall possible,
  especially across the N/NE.

* Shower/storm chances remain high through at least Sun/Sun night,
  perhaps into Mon/Mon night, with a slight drying trend thereafter.

Sat/Sun: Convection chances should be fairly high Sat afternoon and
night, and again Sun/Sun night. The strong ridge centered over the
Southeast coast early Sat will retrograde slowly westward through
Sat night, forced by a leading weak shortwave trough that will track
from the Ohio Valley early Sat eastward across the Mid Atlantic
through early Sun. Low level thicknesses will remain anomalously
high Sat, esp E of the Piedmont surface trough, with continued high
dewpoints in the mid 70s Sat afternoon resulting in another hot day
with heat index values near or exceeding 105 from the Triangle to
the SE. Given the consecutive days of high heat indices which
increases heat-health stress, a heat advisory may be needed Sat for
a portion of the CWA. By Sun, more pronounced northern stream
troughing digging over the Northeast states and Canadian Maritimes
is projected to place our area within stronger NW steering flow with
an increased chance of upstream MCSs or at least MCVs tracking over
our region. This increase in cyclonic mid level flow across our N
and NE late Sat into Sun should support increased storm
organization, and when coupled with PWs of 125-135% of normal favors
a risk of heavy rain, particularly N and NE. Expect highs both days
of 88-97, followed by muggy lows mostly in the mid-upper 70s.

Mon-Wed: A backdoor surface cold front associated with the
aforementioned troughing down through the Northeast states and Mid
Atlantic is shown by a few models dropping into, and perhaps
through, NC on Mon. However, synoptic frontal passage (as opposed to
passage of a mesoscale outflow boundary) can be hard to come by in
the middle of summer across this region, so there is some skepticism
in the scenario of drier air working into our N and NE late Mon/Mon
night, as the ECMWF and GFS depict. Will carry good chance to likely
pops Mon/Mon night, highest W/S, from the Triad SE through the
Sandhills/S Coastal Plain, but this orientation of highest pops may
change in later forecasts. Otherwise, as the Northeast trough
weakens and lifts further NE and away from NC, the ridging aloft
should ease back eastward, resulting in a trend toward more typical
scattered and disorganized late-day storms with subtle foci. Expect
temps to trend back closer to normals, with highest in the upper 80s
to lower 90s and lows around 70 to the lower 70s. -GIH

&&

.AVIATION /08Z WEDNESDAY THROUGH MONDAY/...
As of 435 AM Thursday...

Updated TAFs to account for widespread sct-bkn MVFR to IFR clouds
that have developed across central NC terminals. Periods of MVFR to
IFR cigs are possible 08z-13z at all sites. These clouds should mix
out to sct while lifting, and all sites should be VFR by 15z this
morning.

Earlier discussion from 145 AM: VFR conditions present across
central NC are likely to dominate through the next 24 hours, however
the confidence in VFR conditions during the early morning hours (09z-
13z) is not high. Recent mornings have seen fairly high coverage of
sub-VFR cigs and vsbys in fog, and with minimal change in the
overall pattern, it is reasonable to lean toward persistence here,
especially with low dewpoint depressions over much of the area. But
with winds holding up just a bit early this morning, the lack of any
low clouds or fog formation so far, and the lack of such indicators
in most computer model guidance, it`s looking more likely that VFR
conditions will mostly hold at central NC terminals this morning,
except at FAY where temps and RH are high and where some guidance
suggests areas of stratus developing late. Expect a few clouds below
3kft AGL, mainly across the S and E. Otherwise, expect VFR
conditions through the day, with a chance of TSRA restricted to near
INT and GSO for now, and will monitor convective trends elsewhere as
coverage may be limited. Surface winds will be from the SSW or SW at
5-8 kts through mid morning, then 8-12 kts with a few gusts to 15-19
kts through late afternoon, when speeds will again fall below 10 kts.

Looking beyond 06z Fri, higher coverage of showers and storms is
expected Fri afternoon through evening, esp across the NE (including
RDU/RWI), and a good chance for sub-VFR cigs/vsbys should follow
areawide Fri night into Sat morning. Higher coverage of storms is
again expected Sat afternoon through Sat night. Confidence in storm
coverage drops for Sun/Mon, but we may still see scattered late day
storms and early-morning sub-VFR fog and stratus. -GIH

&&

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

&&

$$

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