Morrisville, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

145
FXUS62 KRAH 191858
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
258 PM EDT Sat Jul 19 2025

.SYNOPSIS...
A series of upper level disturbances will track east and southeast
through the Mid Atlantic region today through Monday, as a backdoor
cold front approaches from the north. This front will drop south
through North Carolina early Tuesday, allowing a cooler and drier
air mass to build in from north late Tuesday through Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 255 PM Saturday...

Water vapor imagery shows westerly flow across central NC, between
ridging over the eastern Gulf and Deep South and troughing over
eastern Canada. A series of mid-level perturbations over the
southern Appalachians will move east across our region late this
afternoon and this evening and result in weak mid-level height falls
on the order of 10-20 m. At the surface, a weak trough will remain
in place over the southern Mid-Atlantic, with a boundary draped
across the northern Mid-Atlantic. A moist and unstable air mass
persists to the south of the boundary with PW values in the 2 to 2.2
inch range and MLCAPE in the 2000-3500 J/kg range according to the
latest SPC mesoanalysis.

Given the above factors, scattered to locally numerous showers and
storms are already beginning to develop over the Mountains and
Foothills, and a couple clusters have developed over the northern
Piedmont and northern Coastal Plain. These showers and storms will
continue to spread east across central NC for the rest of the
afternoon into the evening. Based on the latest CAMS, radar trends,
area of greatest instability, and expected track of the mid-level
impulses, the greatest coverage should be across the northern
Piedmont and northern Coastal Plain. Forecast soundings indicate 15-
25 kts of 0-6 km shear at most, and slightly less DCAPE than
yesterday on the order of 600-800 J/kg. Still, can`t rule out an
isolated damaging wind gust with any storm. As for the heavy rain
threat, given the high PW values and slow expected storm motions
(around 10-20 kts), flash flooding can`t be ruled out. However,
think this threat will be fairly isolated as most areas have had at
least a few days to dry out from recent heavy rainfall and higher
LPMM amounts of 1-3 inches on the HREF and REFS are very spotty,
with more widespread heavy totals over VA as the front is well to
our north (even moreso compared to yesterday). HREF neighborhood
probabilities of exceeding FFG are also on the low side (10-20%).
The greatest threat will be in urban areas and where storms train.

A Heat Advisory is also in effect for central NC outside of the NW
Piedmont until 8 PM today. High temperatures are forecast to reach
the lower-to-mid-90s, and dew points are in the lower-to-mid-70s
(even some upper-70s in the Coastal Plain). So heat indices will
reach as high as 105-107.

Convection will weaken and move to our east by around 00z-03z as we
lose daytime heating and the mid-level perturbations exit the area.
Skies will become mostly clear but the humidity will keep mild low
temperatures ranging from lower-70s in the NW Piedmont to mid-to-
upper-70s elsewhere.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 255 PM SATURDAY...

A broad mid/upper trough over the Northeast US and Mid-Atlantic
associated with a closed low over eastern Quebec will push east into
the Atlantic on Sunday and Sunday night. A surface low will move
east across Upstate NY and New England, with the associated trough
extending south into the Mid-Atlantic. Weak subsidence and NW flow
in the lower and mid levels behind a departing shortwave rounding
the base of the trough will result in decreased shower and storm
chances on Sunday across central NC. But 2000-3000 J/kg of MLCAPE
and a moist air mass (PW values 2+ inches) mean isolated convection
will still be possible. DCAPE looks higher than today (around 800-
1000+ J/kg), so a localized damaging wind gust can`t be ruled out
with any storm, particularly in the north where mid-level flow of 25-
30 kts will be possible.

Heat will be the more widespread concern, as slightly higher low-
level thicknesses, NW downsloping flow, and less
clouds/precipitation will help temperatures rise a bit higher than
today, with highs ranging from lower-90s in the far north to upper-
90s in the far south. Statistical and high-res guidance indicate dew
points will mix out a bit more compared to today with the deep NW
flow, but heat indices are still likely to reach as high as the 105
to 109 range for most of central NC outside of the far NW.
Considered adding the Triad to tomorrow`s Heat Advisory, but given
the NW flow and observations only indicating upper-90s heat indices
there today, opted against issuing one for them, and kept the
counties covered by the Heat Advisory the same as today.

Any convection will quickly diminish after dark with lows Sunday
night not offering a lot of relief, mostly mid-to-upper-70s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 200 PM Saturday...

* Continued high rain chances Mon, but drier weather arrives for the
  rest of the work week.

* Hot weather eases a bit Mon, then temps head trend below normal
  for midweek before the heat returns once again Thu/Fri.

The strong and persistent upper ridge over the Southeast US will
slowly shift westward toward the southern plains by the beginning of
the week, allowing a shortwave to spill over the top of the ridge
and etch out a modest trough along the Atlantic coast.

On Mon, the presence of the approaching front from the north amidst
continued weak to moderate instability, PW of 100-150% of normal and
slightly faster mid-level flow will present an increased chance of
showers and storms in the afternoon and evening. We expect the
coverage to either be greatest across the south or ultimately evolve
to the south once storms develop, which is where SPC currently
carries a marginal risk of severe storms.  The high PW and slow
moving or merging nature of the storms will also create a threat of
localized flooding once again, although some areas across the south
have not seen as much rain as the water-logged central Piedmont.

The front is forecast to push south of the area by Tue, but the
drier post-frontal air is forecast to lag, and a shortwave may move
in from the NW and keep POPs in the 30-40 percent range again across
the south of Tue.  Looking past Tue, the trend will be toward near
to even slightly below normal temps for a couple days, with little
chance of afternoon storms as high pressure extends through the
mid_Atlantic region in cad-like fashion.  However, the high will
eventually retreat and give way to return flow as the subtropical
ridge quickly becomes reestablished across the southern US by next
weekend.


&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 135 PM Saturday...

Generally VFR conditions will give way to scattered thunderstorms
with MVFR conditions this afternoon into the evening. Most of the
storms may stay to the north of KFAY. The scattered storms will
weaken and move east this evening, with generally VFR conditions
returning.

Looking beyond 18z Sun, scattered storms are possible both Sunday
and Monday. However, generally VFR conditions are expected.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for Ncz028>011-
024>028-040>043-073>078-083>086-088-089.
Heat Advisory from 11 AM to 8 PM EDT Sunday for Ncz028>011-
024>028-040>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Danco
SHORT TERM...Danco
LONG TERM...BLS
AVIATION...Badgett