597
FXUS62 KRAH 050857
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
355 AM EST Wed Feb 5 2025

.SYNOPSIS...
A backdoor cold front pushing southward through the area will settle
south of North Carolina this morning, allowing clouds and cooler
high pressure to spread in from the north and northeast. Surface low
pressure developing near the North Carolina coast later today, along
with passing upper level disturbances, will bring rain chances to
the region later today into Thursday. The cool air mass will weaken
and dissipate, giving way to warmer southwest flow from late
Thursday through Friday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 315 AM Wednesday...

Confidence in the forecast for today/tonight is lower than usual for
a Day 1 forecast, although we do know that today`s weather will
differ drastically from Tuesday`s record-breaking warmth and bright
sunshine, thanks to the backdoor front that will settle S of NC
today as cool high pressure builds in from the NNE. A weak 925 mb
low is expected to form over far SW NC early this morning just atop
the surface front, and as this low drifts E along the front, moist
isentropic upglide at 285-295K will facilitate development of
stratocu areawide. Formation of an inverted trough/coastal front is
likely near the NC coast today, which will deepen and focus the
deeper moist upglide over the Coastal Plain for a time, starting
this afternoon. However, overall, forcing for ascent will be fairly
limited today, including a lack of both mid level DPVA within a
fairly flat flow and jet-induced upper divergence, and this is
reflected in the latest CAMs and HREF probabilities as well as the
coarser models which uniformly show much lighter precip with less
coverage, focused mainly in the E, as compared to model runs from
the last couple of days. Forecast soundings show a lack of ice in
the clouds as well, with limited moisture above 0C, thus any precip
should be quite light with small hydrometeors, primarily light rain
or drizzle. Will stick with a trend toward low chance pops mainly in
the E half this afternoon, with isolated or no pops in the west.
Temps today are a challenge, with considerable cloudiness but with
lower precip coverage that will allow for a bit more warming, esp
near the synoptic and coastal fronts over our far S and SE, where
the NBM shows a 12+ degree F range between the 25th and 75th
percentiles. Confidence in temps is better in the far N and NE,
where the cold air is more assured. Will bump highs up a bit from
the earlier forecast, esp in the S, to range from the low 40s N to
the low-mid 50s in the far S and SE.

Tonight, low pressure forming on the coastal front will track NNE
overnight, leaving a residual cool/stable pool over central NC with
winds becoming lighter, while the frontal zone holds across SC,
wraps around the S Appalachians and becomes a warm front through E
TN and into the Ohio Valley. As the coastal low departs, we should
see the better light precip coverage over the Coastal Plain shift to
our E this evening/tonight, a trend noted on the HREF output. Later
tonight, a weak mid level shortwave that will pass over the Plains
today will shift E through the lower Great Lakes and into the
Northeast and northern Mid Atlantic region through tonight. While
the bulk of the precip associated with this feature will pass by to
our NW and N, along the aforementioned frontal zone and near the
nose of an attending 850 mb southwesterly jet and intense upper
divergence maxima, the higher precip coverage may brush across our N
overnight, and will have a swath of brief likely coverage near the
VA border counties with lower chance pops elsewhere, as the latest
models differ in the details but agree on fairly low amounts and
coverage over much of central NC tonight. Expect lows from the mid
30s to lower 40s under thick low overcast clouds. -GIH

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 355 AM Wednesday...

The coastal low is expected to be just off the SE VA coast early Thu
morning, with a very weak and diffuse frontal zone extending through
E NC into W SC, enclosing the residual cool/stable pool with weak
surface winds holding over the NC Piedmont and W Sandhills into the
Foothills. The synoptic front loosely attached to the W edge of the
stable pool is expected to still be over far E TN before it becomes
a warm front surging northward through the Ohio Valley. As the
parent high that deposited the cool air over the Piedmont will have
shifted well out over the NW Atlantic and will no longer be
connected to the stable Piedmont air (thanks to the coastal low off
VA), leaving our stable pool vulnerable to dissolution as it faces
heating from above and strong WAA just aloft. That said, the mixing-
out of a residual post-wedge stable pool over central and western NC
remains a forecast challenge. There is likely to be a lingering
chance for rain in the NE Thu morning, as the deeper forcing for
ascent crosses VA and the Mid Atlantic region. This should be
followed by a relative lull in precip, esp over the southern half, S
of the Triangle, where guidance show neutral or even slight sinking
and drying through the column from late morning through the
afternoon in the wake of the wave passing to our N. The latest
models do show a robust low level SW flow and lowering stability
within the surface-based layer, esp across our S and E areas,
however some shallow cooler air may linger in the Triad through the
day, particular if there is enough moisture to support scattered
showers there in the afternoon. Will carry 20-30% shower chances
roughly north of Hwy 64 Thu afternoon. Expect highs mostly in the
upper 60s to mid 70s Thu, but will keep some low-mid 60s in the NW.
Will extend these pops into the evening and spread them a bit
further S, as we get uniformly into the warm sector ahead of the
approaching front. The CAPE looks to be quite small and elevated Thu
afternoon/evening, so will keep the thunder mention as just
isolated. The front is expected to hold NW of the forecast area
through Thu night, however a prefrontal trough is likely to drop
into the N Piedmont late. Lows will be mostly in the 50s. -GIH

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 243 AM WEDNESDAY...

Friday through Sunday: Flow aloft will turn more nwly on Friday as a
sfc cold front slides to our south. This should limit precipitation
chances for much of Friday (best chances across the south, although
still limited).  Nely flow flow will then build overnight Friday
into Saturday, as yet another wedge of colder air and overcast
conditions lock back in across central NC.  Highs on Saturday may
range from upper 40s (NE) to lower 60s (NC/SC border). Rain chances
should be fairly low and sporadic on Saturday, primarily driven by
weak isentropic lift.

As we pivot to Sunday, the cold air wedge will quickly erode as warm
swly flow develops out ahead of another cold front. Highs on Sunday
will likely reach back into the 70s. Weak mid-level perturbations
and sfc convergence will promote some continued rain chances on
Sunday. However, ensemble guidance is in pretty good agreement
suggesting QPF could be quite low (a few hundreds at best) through
Monday morning.

Monday through Tuesday:  Things get a bit more interesting Monday
into Tuesday as models are finally hinting at a bit more
energy/amplification aloft. A heavy dose of mid-level perturbations
and height falls embedded within a strengthening southern-stream jet
could possibly start spilling into our area Monday through Tuesday.
With some colder air expected to be in place by Tuesday, ptype
concerns may arise. For now, will continue to mention likely rain
with slight chance snow early Tuesday for the northern two-thirds of
the CWA. However, this surely could change as we get closer to early
next week.


&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 105 AM Wednesday...

A backdoor front now dropping SSW through central NC is bringing
surface winds around to be uniformly from the NE at all sites. VFR
conditions persist across central NC, although these mostly clear to
fair skies will give way to increasing clouds based at 3500-4000 ft
AGL that are expected to develop areawide starting after 09z. Cigs
will slowly lower later this morning into the afternoon, and the
best chance of cigs dropping to MVFR will be between 16z and 20z. A
trend to IFR cigs is then expected at all TAF sites between 23z and
02z, with patchy MVFR vsbys developing as NE surface winds lessen to
under 5 kts. There is a chance for light rain later today, best
chance at RWI/FAY starting this afternoon and extending into
tonight.

Looking beyond 06z Thu, sub-VFR conditions are likely to persist
through daybreak Thu, with patchy light rain possible mainly at
northern terminals tonight. After this time, we`ll have a generally
active weather pattern but with a low confidence in timing and
details, as a frontal zone wavers across the Mid Atlantic and
Southeast through the weekend. Low cigs are likely to linger at
INT/GSO/RDU through Thu, while some breaks and lifting of low clouds
may bring VFR conditions Thu aftn to FAY/RWI, perhaps reaching RDU
prior to sunset Thu. Areas of sub-VFR conditions may return Thu
night, but confidence is low. VFR conditions are expected to
dominate Fri, but another weather system may bring sub-VFR
conditions once again Sat into early Sun. -GIH

&&

.CLIMATE...

Record High Temperatures:

February 9:
KGSO: 69/1994
KRDU: 75/2023
KFAY: 75/2023


Record High Minimum Temperatures:

February 9:
KGSO: 52/1994
KFAY: 60/1937

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM..Luchetti
AVIATION...Hartfield
CLIMATE...RAH