857
FXUS62 KRAH 170800
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
400 AM EDT Fri Oct 17 2025

.SYNOPSIS...
Canadian high pressure will build across and offshore the Middle
Atlantic states through Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 340 AM Friday...

A longwave ridge extending this morning from the e-cntl Gulf to the
upr Great Lakes will progress ewd and into the Middle Atlantic
through 12Z Sat. Meanwhile, a shortwave perturbation now over ern TX
will deamplify while lifting newd, through the wrn periphery of the
aforementioned ridge, and into the srn Middle Atlantic. The latter
feature will be accompanied by a shield of cirrus and cirrostratus
that will overspread cntl NC late this afternoon and especially
early tonight, with southwest to northeast clearing likely
across the srn Piedmont and Sandhills late.

At the surface, Canadian high pressure will drift ewd and across the
Middle Atlantic and Carolinas. Associated light and variable wind
today will quickly calm with nightfall.

Temperatures today will be near to slightly below persistence ones
in the mid 60s to lwr 70s. Although the aforementioned high clouds
may limit otherwise optimal radiational cooling with widespread
calm, their limited opacity and longevity should allow low
temperatures to reach the 40s throughout cntl NC.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 355 AM Friday...

Shortwave ridging will briefly re-amplify across the Carolinas Sat,
between a weakening perturbation that will move across and offshore
the srn Middle Atlantic and an upstream trough forecast to amplify
across the MS Valley and mid-South by 12Z Sun.

At the surface, high pressure initially centered over the ern
Carolinas will drift offshore and promote the development of a
warming, return, sly flow ahead of a cold front that will approach
from the west and stretch by 12Z Sun from a deepening, 990-995 mb
low over MI, swwd into the lwr MS Valley.

The warming/modifying airmass over cntl NC will remain deeply dry,
capped, and stable. As such, skies will be mostly sunny/clear,
except for some lingering high clouds across nrn NC with the
deamplifying perturbation Sat morning and some additional, late
arriving ones Sat night, ahead of the aforementioned upstream
trough. Temperatures will consequently trend above average, with
highs in the 70s and lows in the 50s, with the latter regulated by a
stirring, sly breeze in a tightening MSL pressure gradient between
the departing/offshore high and the approaching cold front.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 355 AM Friday...

A deep mid/upper trough will traverse across the OH and TN Valleys
on Sunday, becoming negatively tilted as it crosses the Appalachians
and Mid-Atlantic on Sunday night. An associated surface cyclone will
move NNE from MI into SE Canada, dragging a cold front to its south
that crosses central NC on Sunday night and is associated with a
likely decaying band of showers. The deterministic GFS and CMC are a
bit wetter than last night, but their ensemble means still only
depict around a tenth of an inch or less. The ECMWF and many of its
ensembles continue to be slightly wetter than the GFS and CMC
because they dig a deeper trough and develop a secondary low over
the northern Mid-Atlantic. However, the ECMWF is trending drier and
toward later development of the low, with the 00z run not closing it
off until PA/NJ instead of over the OH Valley. Also, the total QPF
of the deterministic and ensemble mean is still only a tenth to a
quarter inch. Think the best upper forcing being well to our north,
meager instability, and overall progressive nature of the system
will really limit rainfall amounts. So not expecting any hazardous
weather or a significant dent in the ongoing abnormally dry and
drought conditions across our region. The biggest impact may end up
being strong SW winds during the day Sunday, as there will be a
tight pressure gradient between the low over SE Canada and broad
high pressure in the western Atlantic. Model soundings and planar
data indicate frequent gusts of 25-35 mph, and can`t rule out some
in the 35-40 mph range especially in any showers. High temperatures
will be above normal and range from lower-to-mid-70s in the northern
Piedmont to upper-70s elsewhere. Forecast lows Sunday night are
upper-40s to lower-50s.

Monday will turn sunny and cooler as high pressure builds in behind
the front. NW downsloping flow will bring dew points down to the 30s
and lower-40s, and while confidence in wind gusts is low and will
depend on whether that secondary low develops, can`t rule out some
fire weather concerns especially if rain the previous day is very
limited. Forecast highs are in the mid-60s to lower-70s on Monday
with lows in the mid-to-upper-40s on Monday night. Another cyclone
looks to track east from the Upper Great Lakes into New England on
Tuesday and Wednesday, dragging another cold front through central
NC on Tuesday night. However, this low looks weaker and the
associated mid/upper trough broader. Deterministic and ensemble
guidance has even lighter amounts (if any) compared to Sunday`s
event. After a brief warmup on Tuesday with highs in the 70s, it
will cool down again on Wednesday/Thursday to mid-60s to lower-70s,
under sunny skies as high pressure builds back in.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 200 AM Friday...

Canadian high pressure and associated dry air and influence for VFR
conditions, and light and variable surface winds, will build across
NC through tonight.

Outlook: Strong and gusty swly surface winds will result Sunday
ahead of a cold front that will move across cntl NC with an
accompanying band of low VFR to MVFR ceilings and chance of showers
Sunday evening.

&&

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

&&

$$

SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...Danco
AVIATION...MWS