Nc State University, North Carolina Weather Forecast Discussion

746
FXUS62 KRAH 221752
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
152 PM EDT Mon Sep 22 2025
.SYNOPSIS...
High pressure will continue to extend across the Middle Atlantic
today, then weaken and merge with a larger high near Bermuda through
mid-week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Monday...
NWP guidance indicate a sub-tropical shortwave perturbation, now
evident in GOES-E WV data along the FL Atlantic coast, will weaken
while lifting newd along and just off the coast of the Carolinas
through this afternoon, during which time its cirrostratus shield
will bulge nwd across mainly the ern half of NC. A more substantial
shortwave perturbation now pivoting across the nern Gulf will reach
the FL Big Bend later this morning, then turn newd and lift through
the ern Carolinas through tonight and exit the srn Middle Atlantic
coast around 12Z Tue. Related to the approach of this feature, a
separate area of cirrostratus is forecast to blossom across the ern
Carolinas later this afternoon through early tonight. Weak lapse
rates and deep dryness characterized by below average PWs evident in
00Z RAOBs across the South Atlantic coast, and stability, suggest
the aforementioned high-level moisture will be the extent of
sensible weather impacts for cntl NC.
At the surface, the center of a surface ridge, evident in surface
observational data from the Middle Atlantic coast swwd across the
cntl Carolinas and GA this morning, will drift slowly sewd and reach
ern NC by this evening, where it will remain through early Tue.
Light nely flow over cntl NC early today will gradually veer to
ssely in the Piedmont and ely in the Coastal Plain through this
evening.
While the veering, return flow regime across the Piedmont may allow
temperatures to warm a degree to three relative to Sunday, provided
areas of low morning overcast lift and disperse as expected, high
temperatures and distribution should otherwise be generally
persistence, as will overnight lows amid occasional light sely
steering between calm. A redevelopment of stratus and fog, some
possibly dense, will be most likely near the surface ridge axis in
the ern Carolinas late tonight-Tue morning, which would favor the
Sandhills, Coastal Plain, and perhaps far ne Piedmont in cntl NC.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 1240 PM Monday...
A short wave trough passing across the Ohio Valley may extend far
enough south, that when coupled with afternoon instability and
localized lift via the Piedmont trough... could result in a few
stray showers/tstms across our NW Triad zones Tuesday afternoon and
evening. Elsewhere and farther east across central NC, fair weather
is expected due to the lingering ridge and slightly drier airmass.
Temps will continue to run above average for this time of year, and
perhaps a couple deg warmer than today.  Highs in the mid 80s north
and northwest to around 90 south and southeast. Lows Tuesday night
in the 60s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 100 PM Monday...
An upper level low will be over the Great Lakes Wednesday morning
with an associated surface low across the Central Plains. Can`t rule
out a couple of showers Wednesday or Wednesday night across the
northern half of the forecast area, but the more likely chance for
rain will begin Thursday afternoon along and west of US-1. Rain is
likely across all locations Thursday night and Friday. There`s a bit
of model disagreement as to how quickly rain will move out - the 00Z
ECMWF dries things out pretty quickly Friday night, while the 12Z
GFS keeps a chance of showers through the weekend. The official
forecast keeps a 40-50% chance of showers Friday night, a 30-40%
chance of showers Saturday, then a 20% chance of showers Saturday
night and Sunday.
Hazards: Considering the slow movement of the system, there is a
marginal risk (level 1 of 4) of flash flooding Thursday along and
west of US-1, then across all locations on Friday. Despite the dry
conditions recently, the storm motion will likely be along the front
itself, meaning that storms could repeatedly move across the same
area. In addition, while there is a slight chance of thunderstorms
on Thursday and Saturday, the most likely day for thunderstorms will
be Friday as that will be the day with the greatest instability.
Considering the strength of the accompanying upper level system,
Friday could have some strong to severe thunderstorms, although the
Storm Prediction Center currently does not include any locations in
their outlooks past Wednesday.
Temperatures: Wednesday should be the warmest day out of the next
seven, with highs ranging from the mid 80s to the low 90s. Highs
will drop a few degrees each day with additional cloud cover and
chances for rain, with highs on Saturday/Sunday around 80 and in the
70s on Monday. Lows will mostly be in the 60s, with some upper 50s
across the north Saturday and Sunday nights.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 150 PM Monday...
24-hour TAF period: Unlike yesterday, skies cleared quickly this
morning across central NC, with VFR prevailing at all sites. VFR and
dry weather will continue everywhere through this evening. An upper
disturbance will bring a shield of mid and high clouds to central
NC, especially east, from this afternoon through tonight. There may
also be enough lingering low-level moisture for some shallow fog and
very low stratus late tonight and early tomorrow morning, mainly in
the east (including RWI and FAY) as the ridge axis will be shifted
east then compared to this morning. With the 12z HRRR and HREF
probabilities slightly backing off on fog compared to previous runs,
and the lack of its widespread development the last few mornings,
confidence in widespread fog occurring tonight is low, so went with
TEMPO groups for this potential instead of prevailing lines at RWI
and FAY. Any fog would quickly dissipate after sunrise. Winds will
veer from E/NE now to SW by tomorrow morning, remaining light (7 kts
or less).
Outlook: Areas of stratus and fog will be possible again Wed and Thu
mornings, mainly at and east of RWI and FAY. Showers/storms are
expected to reach INT/GSO with isolated coverage late Tue afternoon-
evening and with scattered coverage Wed afternoon-night. Their
probability of occurrence will increase and overspread the west on
Thu and all of cntl NC Thu night and Fri, with associated flight
restrictions. Scattered showers may linger into the upcoming
weekend, as a slow-moving trough aloft and surface cold front
approach our region.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...np
LONG TERM...Green
AVIATION...Danco/MWS

NWS RAH Office Area Forecast Discussion