780
FXUS62 KRAH 010247
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1047 PM EDT Mon Jun 30 2025

.SYNOPSIS...
Sub-tropical high pressure centered south of Bermuda will gradually
lose influence over the South Atlantic states as a mid and upper-
level trough and surface cold front settle into the Middle Atlantic
and Carolinas Tuesday and Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 900 PM Monday...

Convection has largely dissipated across the region this evening. A
few isolated storms across the western Piedmont are seen on radar
but expected to stay sub severe. The chance of precip will continue
to dwindle across the NW Piedmont over the next hour or two as we
loose heating with the sunset. However have a low end slight chance
for precip until around midnight for the NW in case another
shower/storm develops. Otherwise, a quiet night is expected with some
patchy fog possible in the SW Piedmont and Sandhills region early
Tuesday morning. Lows will be in the low to mid 70s across the
region.

As of 350 PM Monday...

The previous forecast and rationale remain mostly unchanged. While
skies will generally clear with loss of heating and diurnal cumulus
and convective debris cloud dissipation, there is a signal in model
guidance for the development of low stratus over the Sandhills and
srn Piedmont Tue morning. A period of partly to mostly cloudy
conditions will consequently be possible then and there, with near
persistence low temperatures in the lwr-mid 70s.

.PREV DISCUSSION... /ISSUED 1100 AM EDT Mon Jun 30 2025/

A weakening mid/upr-level low over the Southeast in recent days had
edged as far northeast as the nrn GA/SC border on Sunday, with
associated cyclonic flow and influence extending across the wrn half
of NC. However, water vapor satellite data indicate that feature has
since drifted swwd to the s-cntl GA/AL border this morning, while
continuing to weaken. Anticyclonic flow has consequently become
established through the mid/upr-levels throughout cntl NC, which may
further decrease convective coverage in cntl NC relative to Sunday.
Nonetheless, the heat and humidity will contribute to another day of
moderate destabilization and little to no CINH, so there will remain
a 15-30 percent chance of convection, particularly where a surface
trough will support weak convergence over the wrn/srn Piedmont and
wrn Sandhills.

&&

.SHORT TERM /TUESDAY/...
As of 340 PM Monday...

* Continued hot and humid, with convection to become numerous over
  the srn and wrn Piedmont during the afternoon

The wrn periphery of a sub-tropical high centered near and south of
Bermuda will continue to weaken and break down through Tue. It will
do so owing to both the passage near the South Atlantic coast of a
mid/upr-level low now north of Grand Bahama and also with the
approach of a positive tilt mid/upr-level trough that will progress
from ON to the cntl Plains this afternoon to QC through the mid MS
Valley by 00Z Wed. The latter trough will be immediately preceded by
a convectively-amplified one, and MCVs from clusters of pre-frontal
convection now stretching from the Middle Atlantic to the srn
Plains. While a broad area of weak, 10-20 meter mid-level height
falls will result over VA and the Carolinas, stronger, mesoscale
forcing for ascent will be maximized along the track of any lower
predictability MCVs.

At the surface, a Piedmont trough will remain over cntl NC,
downstream of an outflow-reinforced and modulated front that will
approach from the northwest and extend from the nrn Middle Atlantic
coast to the mid-South or TN Valley by 00Z Wed.

Diurnal convection will become increasingly numerous over the
Piedmont during the afternoon. Swly lwr to mid-tropospheric flow
around 20 kts will support multi-cell development within a
moderately unstable and deeply and unseasonably moist environment
characterized by PWs of near 2", with an associated threat of strong
to tree-damaging wet microbursts and (especially) urban flooding.
High temperatures will be mostly in the lwr 90s, with some upr 80s
possible over the nw Piedmont where convection and outflow may
become increasingly prevalent prior to peak diurnal heating.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
As of 230 PM Monday...

* Unseasonably warm weather continues into early next week, with the
  exception of Wednesday when widespread cloud cover and lingering
  rain chances will keep temperatures a few degrees below normal.

A parent shortwave will be motoring through Ontario into the
Newfoundland and Labrador province by Tues evening with the base of
the trailing trough axis over the lower Ohio Valley expected to
swing across the Carolinas through Wed afternoon. This feature,
along with any embedded MCV`s from prior upstream convection, will
act as the primary forcing mechanism for ongoing showers/storms over
the Piedmont of NC early Tues evening. This activity is expected to
continue, although gradually weakening and becoming more localized,
as it slowly shifts eastward through the overnight and into Wed.
Most locations along and west of I-95 should see at least trace
amounts up to around 0.5". Narrow swaths of 1.5" to 2.5" will be
possible and may result in localized areas of flash flooding mainly
in urban corridors. Given the low predictability of these MCVs, as
they depend entirely on the initiation and evolution of convection
that has yet to develop, confidence on more precise locations of
heavier rainfall remains low at this time.

A narrow band of unseasonably high deep-layer moisture extending
through the Mid-Atlantic into the Southeast, will slowly sag
southeastward immediately ahead of the trailing trough axis and
associated cold front reach the Carolina coast by late Wed
afternoon. Cloud cover and precipitation chances through peak
heating will likely keep temperatures up to 5 degrees below normal,
marking the coolest day in the Triangle since early June. Drier air
through a deep layer will overspread the region as surface high
pressure settles overhead through the holiday weekend. One caveat is
that aforementioned cold front is forecast across northern FL, and
models have signaled a chance a low developing along the front.
Models have been split on whether that low would develop over the
northeast Gulf or off the Florida east coast.  No local impacts are
evident in current model guidance, but there could be some
enhancement of POPs over the east by Sun into early next week.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 800 PM Monday...

Isolated showers and storms continue over the western Piedmont
(including around INT and GSO) associated with a surface trough, but
convection is fairly weak and sparse and should dissipate with loss
of daytime heating in the next couple hours. VFR conditions will
otherwise prevail through this evening, but guidance continues to
hint at potential for some MVFR or even IFR ceilings from low
stratus early Tuesday morning. The signal is mainly confined to the
southern Piedmont and Sandhills, and given the lack of low stratus
that occurred this morning, opted to only continue mention of it at
the FAY TAF. However, it cannot be completely ruled out at the other
TAF sites as well. Winds will be mainly from the S/SW around 5-10
kts tonight, before increasing Tuesday mid-morning onward,
potentially gusting to 15-20 kts.

A better chance of showers and storms comes Tuesday afternoon and
evening with the approach of an upper trough. The greatest coverage
will be across the Piedmont, so highlighted this with TEMPO groups
at INT, GSO and RDU and PROB30 groups at FAY and RWI. Gusty winds,
heavy rain, and brief sub-VFR conditions will be possible with any
storms.

Outlook: Scattered to numerous showers and storms will linger
through the first part of Tuesday night, but they should gradually
lessen in coverage and intensity after 06z. Low stratus and fog will
also be possible. Chances for convection will linger on Wednesday
and to a lesser extent Thursday with the slow passage and
dissipation of a weak front. The greatest chances will be in the
south and east. Low stratus and fog will also be possible early
Thursday morning, especially south and east. Mainly dry and VFR
conditions will return for Friday and Saturday.

&&

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

&&

$$
SYNOPSIS...Danco/MWS
NEAR TERM...CA/MWS
SHORT TERM...MWS
LONG TERM...Swiggett/BLS
AVIATION...Danco