Apex, North Carolina Weather Forecast Discussion

449
FXUS62 KRAH 100609
AFDRAH
Area Forecast Discussion
National Weather Service Raleigh NC
210 AM EDT Wed Sep 10 2025
.SYNOPSIS...
High pressure centered over the Northeast will extend southwest into
the Mid-Atlantic and the Carolinas through much of the work week.
Weak disturbances will travel northeast near and along a lingering
frontal zone near the coast through Thursday.
&&
.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 210 AM Wednesday...
* Cloudy and below normal in the east, with a chance of evening and
  overnight light rain or showers from Raleigh north and east
* A mix of clouds and sun in the west and southwest
A rather pesky offshore low, presently east of the Outer Banks, is
churning along a stalled frontal boundary. The system is forecast to
gradually move north and then northeast over the next 24 hours,
reaching the N. Atlantic by Thu morning. Meanwhile, high pressure
will strengthen tonight as the low departs, settling into the
central and southern Appalachians, keeping us in that cool NE flow.
A moist NE flow around the aforementioned low is leading to lots of
stratocumulus clouds moving westward. The edge of the boundary is
presently over the western Piedmont, while it is well entrenched
over the Coastal Plain and eastern NC. This will be the case for
much of today, with little erosion of the stratocumulus deck
along/east of the Triangle. There could be some breaks in the clouds
late in the day over Raleigh, but a better area of sun will be
favored over the Triad as the low departs and flow shifts ever so
slightly from a NNE to a N direction. Highs will again be below
normal, where some spots over the northeast may not get out of the
upper 60s. Otherwise, expect upper 70s to low 80s in the west and
southwest with more sun, mid 70s in the Triangle, and low 70s NE.
Tonight, as the low departs, the low-level moist layer will still be
trapped under the subsidence inversion. That layer is forecast in
the guidance to persist from the Sandhills and central/eastern
Piedmont to the Coastal Plain as another surge of 925 mb high RH
overspreads this region. Forecast soundings also show a shallow
unstable layer above the 925-850 mb layer, allowing for some
isolated rain or showers tonight into early Thu. This is most
favored from RDU north and east. The HRRR/HREF are indicating some
isolated pockets in the NE Piedmont and northern Coastal Plain could
see over a half inch of rain, though most areas will see a tenth of
an inch or less. Raised rain chances in this area tonight to around
30 percent as a result, but they may need to be further increased
with the day shift. Lows will be in the upper 50s W to low 60s E.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 210 AM Wednesday...
* Warmer but still below normal
* A few isolated showers possible over the Coastal Plain into early
  afternoon
High pressure at the surface will persist, with another stronger
high building south out of Quebec Thu night. That should keep us in
that below normal NE flow pattern. Low-level moisture trapped
beneath the inversion will also favor morning stratocumulus,
especially along/east of US-1, with more sunshine in the west once
again. Morning to early afternoon isolated showers over the eastern
Piedmont Coastal Plain are possible tied to some weak lift and
instability, but this activity should wane and models are not as
excited about rain chances compared to Wed night given the low well
away from us at this point. As the high builds down Thu night, the
stratocumulus deck should start to erode from west to east, but
would not be surprised if it hangs on longer than expected over the
Coastal Plain. Highs should be warmer with the airmass modifying
slightly, but tempered by clouds in the east, with upper 70s to low
80s W and mid/upper 70s in the NE. Lows will generally be in the
upper 50s to low 60s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 210 AM Wednesday...
Mild and generally dry mid-September weather expected through early
next week.
Deep moisture is expected to remain mostly offshore Friday through
the weekend into next week. Upper ridging will strengthen once again
to our west, centered from Texas NE through the Great Lakes this
weekend into next week. A trough will remain in place along the
eastern seaboard, with the main trough axis expected to remain to
our east. This will keep the deep moisture, lift, and significant
rain offshore. Our region will likely remain dry Friday through
early next week with surface high pressure extending down the
eastern seaboard from the NE, gradually weakening with time into
Monday. Low pressure will remain offshore; however, an isolated
shower may be possible as far inland as portions of our SE Coastal
Plain Friday into Saturday. Yet, rainfall probabilities will only be
10-15 percent in the SE, and less than 10 percent further inland.
The temperatures should be coolest Friday with highs in the mid 70s
to lower 80s after lows in the 50s. Otherwise, highs in the lower to
mid 80s are expected through the weekend, with mid 80s early next
week. Lows mid 50s to lower 60s Saturday gradually moderating into
the lower to mid 60s early next week.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 210 AM Wednesday...
A mixture of VFR in the west to MVFR in the east will start the TAF
period. Low-level 925 mb moisture moving west-southwest around an
offshore low will favor sub-VFR ceilings over the next 24 hours,
primarily in the form of MVFR at RDU/FAY and IFR-MVFR at RWI. A
brief period of MVFR ceilings is possible at GSO prior to 12z, but
these conditions are not expected to be prolonged or reach INT for
that matter. There is reasonably high confidence that RWI will lift
from IFR to MVFR between 16-18z but remain sub-VFR through the TAF
period. There is some model spread, however, on the timing of
erosion of MVFR conditions at RDU/FAY. This erosion could occur as
early as 15-17z or as late as 20-21z. For now, we opted for the
later erosion scenario given forecast sounding data. Gusts up to 18-
22 kt are again favored during the day, weakening Wed night, with
highest gusts at the eastern terminals. A resurgence of moist NE
flow is favored toward the end of the TAF period, which should favor
a return to MVFR conditions at RDU by the end of the TAF period.
Some weak instability Wed night could favor some isolated rain or
showers, most favored at RDU and RWI, with perhaps some sub-VFR
visibilities.
Outlook: IFR-MVFR conditions are favored Wed night to midday Thu at
RWI, RDU, and FAY, and brief sub-VFR cannot be ruled out at GSO. A
return to VFR should return between Thu night to early Fri, slowest
to return at RWI.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Blaes
NEAR TERM...Kren
SHORT TERM...Kren
LONG TERM...BSD
AVIATION...Kren

NWS RAH Office Area Forecast Discussion