Mount Zion, North Carolina Weather Forecast Discussion

058
FXUS62 KRAH 211150
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
750 AM EDT Sun Sep 21 2025
.SYNOPSIS...
High pressure will extend across the Middle Atlantic through Monday,
then drift to near Bermuda through mid-week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Sunday...
NWP guidance indicate a negatively-tilted shortwave perturbation, now
evident in GOES-E WV data over cntl NC, will lift newd along and
just off the coast of the Middle Atlantic and Northeast through 12Z
Mon. An upstream shortwave perturbation, now digging across the LA
coast, will pivot across the nrn and nern Gulf and FL panhandle
through the same time. Between the two, shortwave ridging --and mid-
level-maximized subsidence-- will migrate newd along the South
Atlantic states, including cntl NC this afternoon-early tonight.
At the surface, a backdoor cold front, evident as a radar fine line
over srn and sern VA Sat afternoon and swrn VA and cntl NC early Sat
night, was progressing swwd across the nrn Sandhills and nw Piedmont
as of 0730Z, around 10 kts. The front marks the leading edge of
richer and deeper low-level moisture characterized by mean mixing
ratio values of 12 g/kg in the nely flow regime sampled by the 00Z
WAL and IAD RAOBs, versus near 10 g/kg in the pre-frontal airmass
sampled at RNK and GSO. A surface ridge, and the aforementioned nely
flow, will follow and build swwd from the Middle Atlantic to the
Carolinas.
That moist, nely flow regime will favor the continued swwd
development and expansion of an area of low overcast from the ne
Piedmont and nrn-cntl Coastal Plain as of 0730Z to the nrn Sandhills
and nw Piedmont through 12-13Z. The low overcast should then lift
and scatter to partly to mostly sunny through midday. The post-
frontal, nely flow regime will also favor less warm, but still above
average high temperatures in the upr 70s to around 80 along the VA
border to mid/upr 80s along the SC border. Generally persistence low
temperatures in the upr 50s to lwr-mid 60s, and redevelopment of
overnight low overcast, beneath areas of mostly thin cirrus and
cirrostratus in swly high-level flow downstream of the nern Gulf and
FL panhandle shortwave, are expected through Mon morning.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 345 AM Sunday...
NWP guidance indicate a portion of the shortwave perturbation
centered over the FL panhandle at the start of the period will
lift/eject newd across the Carolinas late Mon-Mon night, while the
basal portion pivots across the ern Gulf and FL Big Bend.
At the surface, ridging will hold firm squarely over the srn Middle
Atlantic and Carolinas.
The presence of the surface ridge and associated nely flow and
airmass will favor a generally persistence forecast of high
temperatures in the upr 70s to mid 80s Mon, but with variably to
partly cloudy skies owing to both a slower and incomplete
dissipation of morning overcast and also thickening cirrostratus
accompanying the lifting/ejecting shortwave and upr jet. Comparably
persistence overnight conditions mostly in the upr 50s to mid 60s
are forecast for Mon night, along with redeveloping low overcast
that the models suggest may be most extensive through the Coastal
Plain and ne Piedmont through Tue morning.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 359 AM Sunday...
There is good ensemble consensus that an upper low will form over
the central Plains Tuesday/Wednesday before cutting off and
lingering over the mid-Mississippi to Ohio Valleys Wednesday into
Friday. This will initially focus the deeper moisture and
precipitation over the Mississippi Valley Tuesday through early
Wednesday before shifting over our area more-so late Wednesday into
Saturday. Models diverge in their handling of the upper low/trough
Sunday into early next week. However, the overall pattern would
suggest continued unsettled weather through the late weekend period.
By Tuesday, sly flow will develop over central NC and as such expect
highs to peak in the mid to upper 80s.  Some deeper moisture may
spill into our northern areas late in the day, but overall forcing
should focus precipitation again to our west and north leaving us
dry Tuesday.
As the upper low deepens and slowly drifts east-southeast Wednesday
into the weekend ripples of mid-level perturbations will drift
across central NC. With anomalous moisture in place, this mid-level
forcing (in addition to increasing upper forcing associated with the
upper trough/jet) will generate periods of pre-frontal showers and
storms during this stretch. While the speed, amplitude, and
evolution of the upper features are relatively low-predictability
right now beyond Wednesday, there remains potentially hazardous
signals in the guidance outlined below.
Severe Weather: Given the continuous warm, moist sly conveyor flow,
expect marginal CAPE to develop each afternoon Thursday onward.
Coupled with increasing shear from the eastward migrating upper
trough, there could be a few windows for overlap of high shear/low
CAPE during this stretch.  Forecast soundings on Thursday indicate
uni-directional flow with height but increasing hodograph elongation
Thursday afternoon and evening. As such, a few strong to severe
storms could be possible Thursday. On Friday, forecast soundings
suggest the potential for backing of the low-level flow from the sfc
through H9 which could support the potential for rotating storms in
the afternoon and evening. Still a bit far out to get too into
temporal or spatial details, but worth mentioning the potentially
strong kinematics with this system.
Flooding: Given the upper/cut off low is expected to move slowly, we
should see continuous flux of anomalous moisture across the
southeast Thursday into the weekend. With several rounds of rain
expected, and potentially heavy rain on Thursday and Friday, there
will likely exist a low-end chance for flash flooding during this
period.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
As of 750 AM Sunday...
An area of mostly IFR-MVFR ceilings, except LIFR and with visibility
restrictions along its leading edge, overspread RWI and RDU earlier
this morning; and they will likely reach GSO, INT, and FAY through
13Z. Lifting and scattering to VFR will then result between 14-16Z,
with generally light nely surface winds. Continued nely flow will
favor the redevelopment of mostly IFR ceilings and perhaps some
patchy fog and/or drizzle late tonight-Mon morning, with slow
lifting and scattering to VFR through Mon midday-afternoon.
Outlook: Areas of stratus and also some fog will be possible again
Tue and Wed mornings, mainly at RWI and FAY. Showers/storms and
flight restrictions are expected late Wed 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...MWS
LONG TERM...Luchetti
AVIATION...MWS

NWS RAH Office Area Forecast Discussion