-- Discussion containing changed information from previous version are highlighted. --
952
FXUS62 KRAH 261144
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
645 AM EST Sun Jan 26 2025

.SYNOPSIS...
High pressure will hold over the Southeast coast through the rest of
the weekend. A passing upper level disturbance and weak surface cold
front will move over the Carolinas on Monday, followed by another
surface front passage on Wednesday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 130 AM Sunday...

Expect periods of sun and mid/high clouds today with mild temps,
then rain chances arrive in the southwest late tonight.

Surface high pressure centered over S GA early this morning will
continue a slow SE drift today, and despite a low level SW to WSW
flow, we`ll remain cut off from any low level moisture source today.
Further aloft, though, within the fast nearly zonal mid-upper flow,
areas of sct-bkn mid and high clouds over the S Plains through the
middle and lower Miss Valley and Mid South will stream eastward over
the Carolinas, yielding a fair to partly cloudy day. Clouds will be
most opaque this morning through early afternoon, corresponding to
an uptick in upper level ascent within the exit region of a jetlet
to our WNW, followed by a period of fair to mostly sunny skies by
mid afternoon as that upper jetlet passes by just to our N, leaving
us within a brief relative lull in upper level forcing for ascent.
Slightly above normal thicknesses today with decent insolation
indicate highs mostly in the low-mid 50s, a couple of degrees above
normal and in line with the upward run-to-run trend in the latest
statistical guidance.

Then tonight, high level forcing for ascent will return, as the
accelerating jet just off the Mid Atlantic coast (a function of a
shortwave trough dropping SE through the Great Lakes/Midwest into
the Ohio Valley) and another jet over TX and the Gulf states become
ideally juxtaposed such that the Carolinas are beneath the right
entrance region of the former and the left exit region of the
latter. Clouds will spread back in this evening, becoming thicker
with lowering bases esp over the southwest CWA as the column slowly
wet-bulbs from the top down. The associated surface pattern will
remain somewhat diffuse, with a surface cold front approaching from
the N and NW and attempting to link up with low pressure developing
over S MS into AL tonight. This approaching front along with the
weakening and departing surface high to our S and SE will allow our
low level SW flow to initiate fairly deep moist isentropic upglide
at 285K-305K, drawing in sufficient moisture to support light rain
spreading across the southern half of central NC overnight. Both
large scale and hi-res models have trended a bit faster and further
N with light rain chances late tonight, and have adjusted
accordingly, bringing in pops late, highest in the SW but extending
as far NE as the Triangle. The incoming clouds and increase in
groundward IR will keep temps from cooling too much tonight, and
with lows mostly in the mid 30s (with low 30s only in the pop-free
far N), what falls overnight should be just rain. -GIH

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 225 AM Sunday...

The weak but fairly deep moist upglide beneath the upper divergence
max will result in continued rain chances across southern sections
of central NC (highest along and S of Hwy 64) Mon morning. Will
carry a period of likely pops in the far S Mon morning, with lower
chances further north. The moist upglide wanes and becomes more
shallow by early afternoon with drying from the W above 295K, as the
upper divergence max shifts to our E and off the Carolina coast by
18z. This should lead to a NW-to-SE shift of rain chances to the SE
(mainly MEB to GSB and to the SE) in the afternoon, and no pops
after sunset, following the trends of the latest hi-res models and
ensemble output. The diffuse surface cold front moving in from the
NW will closely follow this downturn in ascent as it passes through
central NC Mon evening with gradually drying low levels and a breeze
expected overnight given the tightening MSLP gradient. With the
thicker overcast skies across the S and thinner/fewer clouds in the
far N Mon, expect highs Mon to be lower in the SE (upper 40s to
around 50) and higher over the NW and far N (lower 50s). Expect lows
from the upper 20s to around 30 NW to the mid 30s SE, where clouds
will be last to clear and where some low stratus may linger through
sunrise. -GIH

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 400 AM Sunday...

Much drier air will be in place across central NC from Tuesday
through Thursday with mostly clear skies, as we are under the
influence of NW flow aloft between the departing trough in the
western Atlantic and ridging that gradually builds east from the
Southern Plains into the MS Valley. At the surface, high pressure
will extend from the lower MS Valley into the northern GOM and FL,
as low pressure and the associated mid-level trough move east from
the Upper Great Lakes into New England. While the system will drag a
cold front through central NC on Wednesday evening, guidance has
gotten in good agreement that the troughing will pass too far north
for any precipitation over central NC, with essentially all ensemble
members of the ECMWF, GFS and Canadian now dry. Ahead of the front,
the warming trend will continue, with highs in the mid-50s to lower-
60s on Tuesday and lower-to-mid-60s on Wednesday. Lows Tuesday and
Wednesday nights will be in the 30s. Continued to lean toward
stronger winds in the forecast, as there will be a tight surface
pressure gradient between the high to the south and low to the north
on Tuesday and especially Wednesday. Based on sounding momentum
transfer, gusts of 20-30 mph on Tuesday and 25-35 mph on Wednesday
will be possible. A separate Canadian high will build into the area
on Thursday, bringing much calmer winds and temperatures back to
near normal, with highs in the upper-40s to mid-50s and lows in the
upper-20s to lower-30s.

A closed mid/upper low that had been over the Southwest US from
early to mid week will finally eject east on Friday and Saturday,
but its exact track, timing, and when it devolves into an open wave
are all still very uncertain. The 00z GFS is more progressive and
has it becoming an open wave by the time it reaches the Eastern US,
while the ECMWF and Canadian keep it wrapped up and farther NW over
the Upper Midwest. This will affect timing of precipitation as well
as amounts. For now the forecast has light rain chances beginning
from isentropic lift on Thursday night and Friday, with a better
chance of widespread showers on Friday night and Saturday. While
many ensemble members show rain at some point, POPs stay in the
chance category given the uncertainty in details. Temperatures
should be above normal on Friday/Saturday, and if the warming trend
continues, will have to watch for the possibility of thunder on
Saturday, though instability looks marginal at this time.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
As of 645 AM Sunday...

VFR conditions will continue through early tonight across central NC
terminals, although with increasing clouds overall. High pressure
over the Southeast will weaken and push southeast and offshore, and
areas of mid and high level clouds will stream over the area for
much of the day and evening. Cloud bases will stay well into VFR
territory through 06z, however after 06z, overcast skies will spread
into southwest areas, with FAY likely to drop to MVFR or IFR after
09z with light rain. INT/GSO/RDU will also see lowering cloud bases
overnight, and while these sites should stay VFR, there is a small
chance of MVFR/IFR cigs approaching these sites toward 12z Mon.
Winds will stay light, under 10 kts, mainly from the SW or W through
tonight.

Looking beyond 12z Mon, as clouds continue to increase and thicken
with lowering bases into Mon morning, rain chances will spread west
to east over mainly the southern half of central NC. FAY is likely
to remain sub-VFR with several hours of of light rain into Mon
evening and low clouds holding on through Mon night. Chances of sub-
VFR conditions are lower at INT/GSO/RDU/RWI, but these sites may
still see a period of sub-VFR conditions Mon aftn/evng with patchy
light rain. VFR conditions are likely to return Tue-Thu. -GIH
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Danco
AVIATION...Hartfield