197
FXUS62 KRAH 170614
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
214 AM EDT Thu Apr 17 2025

.SYNOPSIS...
Cool high pressure over the area will push slowly offshore today
through Friday, bringing a warming trend through the weekend and
into early next week. A frontal system will approach from the west
Monday, then stall out and linger over the region through Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 215 AM Thursday...

* Frost Advisory in effect until 8 AM this morning for patchy frost
  in rural areas of the Piedmont.

* Seasonable today, not as cool tonight.

The center of surface high pressure will shift across the Mid-
Atlantic this morning and briefly settle just off the NC coast by
this afternoon. Confluence aloft will help strengthen the surface
high to around 1030mb by Fri morning. Little modification to the
airmass in place will result in similar temperatures today compared
to Wed (upper 60s to low/mid 70s). An elevated warm frontal zone
centered around 500mb will bring an increase to multi-layered
cloudiness late this afternoon through the overnight hours.

With the center of the surface high building just off the coast,
there will be very shallow moisture advection within the light
southeasterly surface flow off the Atlantic. For now, point
soundings suggest this layer will only a few hundred feet thick with
very dry air aloft and may only result in dew at the surface;
however, shallow ground fog and/or a low stratus deck can`t be ruled
out. Overnight lows will settle in the mid/upper 40s to around 50,
but may be a category or two warmer if a low stratus deck forms.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 215 AM Thursday...

* Breezy southwesterly winds bring a pattern change to above normal
  temperatures.

A series of shortwaves over the Intermountain West and just off the
CA coast on Thurs will combine and favor a more amplified mid/upper
level pattern through Fri. Downstream amplification will result in
an anomalous shortwave ridge to shift and further amplify from the
Lower MS Valley to over the Southeast by 12z Sat. This process will
shift the center of the low/mid-level anticyclone from over the Gulf
to over and just off the Southeast Coast in the western N. Atlantic;
this will favor deep warming south-southwesterly flow to begin a
pattern change of anomalous warmth heading into the weekend.

Skies should be mostly clear with only wisps of cirrus clouds
through the afternoon, which should not impact diurnal heating and
allow temperatures to rise well into the 80s (up to 10 degrees above
normal). A tightening pressure gradient at the surface and
increasing momentum aloft should support low-end winds 10 to 15 mph
with frequent gusts up to 25 mph through the afternoon. Overnight
stirring and anomalous warmth will keep overnight lows mild and only
fall to the low 60s (15 degrees above normal).

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 200 AM Thursday...

We have high confidence in warm and dry weather through at least
Easter Sunday night. Moderating but still-mild temps are expected
early next week with the arrival of rain chances Mon/Tue, perhaps
lasting through Wed across southern sections, but details are highly
uncertain.

Sat-Sun night: The low level anticyclone will settle just off the
Southeast coast as strong and deep mid level ridging holds over the
Southeast states and Carolinas, ensuring a steady S and SW low level
flow topped by warm and stable mid levels. As this warmth aloft
inhibits deep convection and as the stream of high PW holds to our W
and NW, we`re likely to stay dry through the weekend. Models are
settling toward greater commonality in showing an anticipated
backdoor front just barely nudging into our NE late Sun, propelled
by a SE Canada polar low and corresponding cool surface high
extending down into the Mid Atlantic coast. This feature appears
fleeting, leaving as quickly as it arrives given the progressive
nature of its driving mechanisms, so expect little more than some
enhanced cloudiness and perhaps briefly lower dewpoints in our far
NE. Models have been consistently clustered around projected warm
low level thicknesses of 25-30 m above normal Sat and 30-35 m above
normal Sun, and given lots of sunshine, we could easily overshoot
NBM deterministic forecast temps. Expect warm highs in the mid 80s
to near 90 both days. Lows will be mostly in the lower to mid 60s.

Mon-Wed: Model solutions remain varied with the longwave pattern,
but they generally depict the potent Plains low tracking into the W
Great Lakes region by early Mon, then becoming a more open wave as
it crosses SE Ontario and S Quebec through Tue and the Canadian
Maritimes Wed, all the while slowly flattening the ridging over and
off the Southeast/FL coast. At the surface, the corresponding
surface cold front is projected to move into W NC Mon, with our area
holding in the warm sector, favoring still-warm highs ranging from
the low 80s NW (with increasing/thickening clouds) to upper 80s SE.
Prefrontal scattered showers with some embedded thunder are expected
to cross the CWA Mon afternoon through Mon night, and while coverage
and amounts are highly uncertain, it doesn`t have the markers of a
particular efficient rainmaker given the modest dynamic forcing for
ascent, so any rainfall amounts should be on the low side. The cold
front should ease ESE into the forecast area late Mon into Tue,
settling over our central or SE sections as weak high pressure
builds over WV. As this high weakens further while drifting into VA,
models generally favor frontolysis, with the now-stationary front
weakening considerably across our S Tue night/Wed, reasonable given
the likely decrease in front-parallel mid level flow over the Mid
South/Southeast/Mid Atlantic regions. Will retain climo-leaning
chance pops in the afternoon Tue areawide and across the S Wed for
now, with continued above normal highs in the upper 70s to lower 80s
as we remain shut off from any source of cooler air. -GIH

&&

.AVIATION /05Z THURSDAY THROUGH MONDAY/...
As of 100 AM Thursday...

VFR conditions are expected through the 24 hour TAF period.
Light and variable winds tonight will continue through the early
afternoon as surface high pressure slides across the region.
Surface winds will become southerly by late Thurs afternoon as
mid/high clouds begin to stream over the Mid-Atlantic.

Outlook: Shallow moisture return early Fri morning (06-12z Fri) may
result in a scattered low-stratus deck at FAY (20 to 40%
chance) and RDU/RWI (15 to 25% chance). Strengthening LLJ of 35
to 45 kts may result in marginal LLWS at all sites Fri night.

&&

.EQUIPMENT...
KRAX will remain down due to a mechanical issue. Technicians are
aware and will be on-site later today to perform unscheduled
maintenance. A return service time is unknown until technicians
can assess the situation.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM EDT this morning for NCZ007>009-
021>025-038>040-074>076.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Swiggett
SHORT TERM...Swiggett
LONG TERM...Hartfield
AVIATION...Swiggett
EQUIPMENT...RAH