298
FXUS62 KRAH 301837
AFDRAH

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

.SYNOPSIS...
Sub-tropical high pressure centered south of Bermuda will extend
westward across the South Atlantic states today, then gradually lose
influence 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 1100 AM Monday...

The previous forecast of persistence hot and humid, with isolated/
widely scattered afternoon-evening showers/storms (relative highest
coverage over the Piedmont/wrn Sandhills) remains on track.

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.

.PREV DISCUSSION... /ISSUED 245 AM EDT Mon Jun 30 2025/

Yet another day of diurnally showers and thunderstorms is expected
across the region. Similar to previous days, the greatest coverage
is expected to be across the west compared to the east. However,
high resolution models are indicating less coverage across the
eastern half of the forecast area than previous days. Thunderstorms
are likely to continue into the evening across the Triad, then
fizzle out by midnight. Once again, highs should be in the low to
mid 90s, with lows perhaps a degree or two warmer with slowly
increasing high cloud cover in advance of the next system.

&&

.SHORT TERM /TUESDAY/...
As of 245 AM Monday...

On Tuesday morning, a cold front will extend from Lake Ontario
southwest into Kentucky and continuing into Texas. Over the last
couple of days, models have slowed the arrival of the front into the
region. While much of the region will still have showers and
thunderstorms on Tuesday, the highest rainfall totals will likely be
delayed to Tuesday night. Considering the delay in the arrival of
precipitation, Tuesday`s high temperatures have come up a degree or
two compared to the previous forecast, but will still range from the
mid 80s to the low 90s.

Much of the forecast area remains in a Marginal (level 1 of 5) risk
for severe weather on Tuesday, which seems appropriate considering
there would be modest instability, but minimal shear to organize
storms. In addition, if things trend closer to the 00Z run of the
HRRR, an even slower solution, more precipitation would occur
overnight when instability would be further reduced. Will not wait
for the new Day 2 WPC Excessive Rainfall Outlook to send out this
discussion, but the Sunday afternoon ERO included much of the
forecast area west of I-95 in a Marginal (level 1 of 4) risk for
excessive rainfall.

&&

.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 /18Z MONDAY THROUGH SATURDAY/...
As of 150 PM Monday...

Widely scattered convection will continue to bubble in the vicinity
of a surface trough over the Piedmont through early to mid-evening,
then dissipate with loss of heating/instability. There is a signal
in model guidance for the development of an area of IFR-MVFR
ceilings over the Sandhills and srn Piedmont and adjacent areas Tue
morning, centered closest to FAY and where a short period of flight
restrictions are indicated in the 18Z TAFs. Some of this cloudiness
may also glance Piedmont sites and require introduction in their
forecasts with later issuances.

Outlook: The chance of showers/storms will increase with the
approach of a mid/upr-level trough and embedded disturbances Tue
afternoon-night, particularly across the Piedmont. Chances for
convection, and also morning stratus and fog, will linger at ern
sites Wed-Thu, with the slow passage and dissipation of a weak
front.

&&

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

&&

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