779
FXUS62 KRAH 241835
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
235 PM EDT Sat May 24 2025

.SYNOPSIS...
Cool and dry high pressure will build from central Canada over the
Mid Atlantic region into Sunday. An unsettled period is expected to
begin late Sunday or Monday as a storm system approaches from the
west.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 235 PM Saturday...

* Increasing cloud cover overnight. Seasonable temperatures.

Periods of mainly mid/high clouds will advect into the region from
Ohio Valley briefly increasing cloud cover over the area through
roughly midnight before collapsing southeastward through the area by
Sun morning.

A stalled frontal boundary draped across the Southeast will
gradually lift northward tonight, but remain well south of the
region into Sun morning. A compact convectively-induced disturbance
rotating through western TN will generally track east-southeast
while becoming sheared out over the Southeast into SC. The low-level
mass response as it approaches is expected develop weak WAA and
isentropic lift over SC into southwestern NC atop the frontal
boundary to our south. This is expected to sustain an area of rain
and some embedded showers mainly along and south of the SC/NC
border. Some very light measurable rain is possible across the
southern Piedmont into the Sandhills late tonight, but overall dry
conditions are expected. Lows will generally settle in the 50s with
some upper 40s possible across the northern counties where a period
of mostly clear conditions will be most likely.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 235 PM Saturday...

* Cloudy with scattered light rain through the afternoon with more
  numerous showers expected after mid-afternoon through the
  overnight period.

The quasi-stationary boundary will generally waffle over the
Southeast and likely not reach into the Carolinas as convection
suppress it back southward. The elevated frontal zone at H850 will
encounter less resistance to lift northward as an area of low
pressure ripples from the Mid-MS Valley Sun afternoon through NC and
off the coast by Mon morning. Periods of scattered light rain will
be possible, mainly after 15z, as anomalous moisture is pulled
northward and lifted by a broad zone of H7 WAA, but the widespread
rain will likely hold off until after 21z.

After this time, a convectively induced disturbance will accompany
the elevated area of low pressure and locally enhance the WAA and
tightening the elevated frontal boundary. Overall this system is
very weak and has areas of displaced synoptic forcing, so it will
likely not bring a significant amount of rain. Forecast totals range
from a couple hundredths to as much as 0.5". There will likely be a
west-east swath of higher rainfall amounts, but this will greatly
depend on the position of the elevated front and track of the low
pressure, but even then, totals may struggle to reach up to an inch.

Highs will be tied to how quickly low clouds and light rain move
into the area, but given widespread cloud cover already in place,
knocked back highs another degree or two than the inherited forecast
resulting in around 70 in the Triad and around 80 in the southern
Coastal Plain. Lows will settle in the mid 50s to mid 60s.
&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 225 PM Saturday...

Highest rain chances of this period appear to be Tue into Tue night.
Another peak in precip chances may arrive Wed or Thu, but model
spread grows quite high by this time, with poor predictability from
mid week on.

Mon-Mon night: The latest NBM and LREF ensemble suites agree fairly
well that, after some early-morning rain mainly across the E CWA
before the low and front push offshore, much of Memorial Day should
be dry, with only small rain chances and low QPF across our S and W
edges, but it`ll be cool as CAD development is likely. The polar low
will move from Nova Scotia out over the NW Atlantic, as a trailing
potent shortwave dives across the N Mid Atlantic region and
offshore. This should nudge both the higher PWs and the surface
front back S, as high pressure over the N Great Lakes builds in,
with a secondary high center forming over the Mid Atlantic. Between
this mid level low and another low/trough digging over the Dakotas
down through the Plains, we`ll see a brief period of low-amplitude
ridging over the Southeast and Carolinas Mon afternoon and night,
resulting in a relative lull in pops. Clouds will be slow to clear,
however, with models indicating high stability and lingering
moisture 950-750 mb into the afternoon, reinforced by an ENE low
level jetlet nosing through the Piedmont, so expect highs only in
the upper 60s to mid 70s, and even this may be optimistic. It should
remain largely dry through the evening, but a ramping up of ESE to
SE flow just aloft riding up and over the CAD stable pool should
induce moist upglide-forced cloud redevelopment and patchy light
rain and drizzle over the W / S Piedmont overnight. Lows in the 50s
NW and 60-65 SE.

Tue-Wed night: High rain/storm chances look to return Tue/Tue night,
but confidence in the details is low. The Mid Atlantic surface high
will shift E and off the coast, but will continue to extend down
through the CAD region Tue. The Dakotas low is expected to deepen as
it shifts slowly E to MN/WI through Wed night, and this will keep us
within weak but gently cyclonic and perturbed flow across the S
Plains through the Mid South and Carolinas, with these perturbations
driven largely by upstream convection and resultant MCVs, hence the
drop in predictability. The NBM, LREF, and WPC superensemble all
indicate a high chance of at least some precip in central NC Tue/Tue
night, but with a large spread in amounts among members, a theme
shared by the latest deterministic models. Will have pops ramping up
to likely to low-end categorical Tue afternoon, peaking Tue
evening/night, but with the knowledge that we could see lower
amounts or pockets of higher totals as alternate scenarios. With
encroaching clouds and precip onset limiting heating, expect cool
highs Tue, mid-upper 60s over much of the Piedmont with low 70s SE.
Lows in the mid 50s to low 60s. Will maintain likely pops into Wed
with the overall flow pattern keeping us in the path of potential
MCVs from upstream convection amidst above-normal PW, but wouldn`t
be surprised to see an embedded period of dry weather. Have held Wed
temps on the low side over the N/W Piedmont Wed, with a blend of
NBM`s 25th percentile, given a good chance of lingering in situ CAD,
despite the slow departure of the parent high. Will have highs in
the low-mid 70s NW ranging to low 80s SE, although the Triad could
struggle to breach 70 if CAD holds. Will have decreasing pops Wed
night with lows generally in the 60s.

Thu-Sat: We should trend to a more typical early-summer pattern of
scattered diurnal-favored convection, with no or isolated pops at
night. Any remaining CAD is expected to be vulnerable and thus
dissipate Thu, as the frontal zone lifts or jumps to our N and NW,
placing us in the warm sector. The low over WI early Thu is looking
likely to be picked up by a polar low plunging S through E Ontario
and Quebec, carving out an amplified longwave trough over E NOAM by
Fri/Sat, resulting in a steady acceleration of increasing cyclonic
flow over NC. Our pops should be above climatology Thu with elevated
PW and potential pockets of high upper divergence with the trough
axis still to our W;  later forecasts may need to go with higher
pops Thu, but for now will keep it at 40-50%. The front is expected
to push to our E and S Fri, although minor vorticity centers
swinging through the trough base may result in weak surface low
development along the front, keeping at least some pops in our area.
Will have near-climo pops, chances during the day and just slight
chance or dry at night. Expect highs mostly in the low-mid 80s with
some upper 70s NW Fri/Sat. -GIH

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
As of 130 PM Saturday...

Low-end gusty winds will generally be out of the west, but may be
variable from southwest to northwest through the afternoon. VFR
conditions are expected to prevail through the 24 hr TAF period.
Cigs will however lower towards low VFR by 18z Sun, especially at
GSO, INT and FAY.

Beyond 18z Sun, cigs may lower to MVFR Sun evening before gradually
falling to IFR to perhaps LIFR Sun night into Mon as periods of rain
become more widespread. Some improvement to MVFR or perhaps VFR is
possible Mon as a backdoor cold front and northerly wind shift moves
through central NC. MVFR-IFR cigs are expected to return by Tues
night as another round of widespread rain moves in and potentially
setting up multi-day CAD regime into at least Wed night. Low-end
LLWS will also be possible as early as Mon night and again Tues
night.

&&

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

&&

$$
SYNOPSIS...Badgett
NEAR TERM...Swiggett
SHORT TERM...Swiggett
LONG TERM...Hartfield
AVIATION...Swiggett