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000
FXUS62 KRAH 180645
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
245 AM EDT Thu Apr 18 2024

.SYNOPSIS...
A weak cold front will move east across the region this morning
and off the coast this afternoon. A stronger cold front will
move across the area late Friday into Saturday, before stalling
near or just to our south. A wave of low pressure will track
along the front along the southeast coast late in the weekend.
Much cooler conditions are expected this weekend.
&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 830 PM Wednesday...

The cold front was still analyzed along the Ohio River this evening,
with a surface trough in the lee of the Appalachians. There
continued to be limited instability and lift to work with over NC
this evening as the best instability was located well to our south,
and the dynamics to our northwest. The front will approach later
tonight with little fanfare. There have been a few sprinkles in the
past few hours, but even the sprinkles were shifting on to the SE,
away from our region. Nearly overcast skies were observed back
into portions of eastern TN. It will be late tonight before
clearing finally works east across the region. Otherwise, expect
mainly cloudy skies through the evening then gradual clearing later
tonight. Pre-frontal warm conditions with a light SW flow will
keep temperatures well above normal. Expect lows in the lower to mid
60s, except some upper 50s NW-N Piedmont if it clears soon enough.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 355 PM Wednesday...

Dry and unseasonably warm-mild.

In the wake of a shortwave perturbation that will shear east and
across the srn Middle Atlantic early Thu morning, progressive
shortwave ridging aloft will build across and offshore the South and
Middle Atlantic Thu-Thu night.

A surface frontal wave, accompanying the aforementioned shearing
shortwave perturbation noted above, will develop along a retreating
warm front across nrn VA/MD through Wed evening and offshore the
DelMarva Thu morning. While an attendant cold front will remain
draped in its wake across the Virginias and lwr OH Valley, a
trailing trough will move east and across the srn Middle Atlantic
Piedmont Thu morning and Coastal Plain through the afternoon. The
passage of the trough will be marked by a light wind shift to nwly
and marked low-level drying characterized by afternoon surface
dewpoints in the mid-upr 40s to lwr 50s. It will remain very warm
south the frontal zone, however, with high temperatures comparable
to those of Mon - 85-90 F. The dry air will also favor a large
diurnal temperature range, with Thu night low temperatures in the
50s, to around 60 in the ern Sandhills/srn Coastal Plain.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 231 AM Thursday...


Upper pattern through the extended: An upper trough will move across
the Great Lakes/northeast Saturday into Sunday promoting primarily
wnwly flow over central NC Saturday.  Flow will turn more swly over
central NC Sunday into Monday as a low-amplitude short-wave moves
through the deep south.  A more vigorous short-wave will drive
through the southeast Monday into Tuesday. Wnwly flow will then
persist into Wednesday.

Saturday: A sfc cold front will sag south into our area on Saturday.
The NAM and GFS move the front south of our area by Saturday
afternoon. The Euro and NBM are a bit slower and allow some decent
warming to occur across our southern areas Saturday afternoon. The
latter scenario would suggest some instability could develop ahead
of the advancing cold front. This would promote the potential for
some showers/storms to potentially form Saturday afternoon/evening.
Decided to lean on the slower solutions and maintain chance POPs
across southern areas (where dew points may reach the lower 60s)
Saturday afternoon and evening. Temps on Saturday will largely
depend on the evolution of the front, but generally expecting mid
70s to lower 80s from north to south.

Sunday through Tuesday: Flow aloft turns swly Sunday and Monday
increasing low-level moisture advection into the southeast. While
guidance is in good consensus generally pinning the cold front along
the coast (and shunting most instability to our south), ensembles
are suggesting a decent soaking may still be possible for some of
our southern areas Sunday evening. The highest QPF amongst ensembles
(GEFS/EPS), some deterministic guidance (ECMWF, CMC), and machine
learning guidance (EC-AIFS) is generally from our Sandhills
southeast across the Coastal Plain/Coastline. Alternatively, the
deterministic GFS and GEPS ensemble suggest some higher QPF
spreading further north into our Piedmont.  Regardless, it looks wet
in this period, especially across our southern areas. Thunder
chances should be minimal as temps cool off into the lower to mid
60s and dew points drop into the mid to upper 40s. However, some
instability could develop over the southern Coastal Plain and
perhaps support some higher rain rates in these areas Sunday
evening. It`s worth noting that WPC has introduced a marginal risk
for excessive rainfall over the southern two thirds of our CWA for
Sunday into Monday.  However, unless instability can indeed promote
higher rain rates in these areas, the current QPF would likely
negate much of a flash flooding threat.

Any lingering rain Monday morning should largely pull off to our
north by early afternoon.  A few additional scattered showers may be
possible Monday afternoon/evening with the passing of the upper
feature, but overall Monday should largely be dry. Tuesday will
follow suit under nwly flow aloft.

Temperatures Sunday and Monday will be cool in the mid 60s. Temps
will rise into the mid 70s Tuesday and Wednesday.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
As of 235 AM Thursday...

24 hour TAF period: VFR conditions are generally expected through
the 24-hr TAF period. A lingering shower is still possible across
the eastern Coastal Plain near KRWI through 08Z. A shield of mid and
high clouds extending from southwest to northeast across the eastern
Carolinas will shift east this morning with generally clear skies
after mid morning through tonight. A couple of exceptions include
the potential for a brief period of MVFR stratus to develop near the
far western Foothills and possibly the Triad area near daybreak this
morning before rapidly dissipating. In addition, an area of
MVFR stratus will move into central NC from the northeast very
late tonight into Friday morning impacting the KRWI and KRDU
terminals toward and especially after 06Z.

Light southwest to west winds at 3 to 7 kts this morning will
gradually veer around to westerly to northwesterly by daybreak.
Northwest winds at 8 to 12 kts with a few gusts of 20 kts are
expected later this morning into this afternoon. Winds will
decrease late this afternoon with winds becoming northeast at 4
to 8 kts between 03 and 09Z tonight. A brief period of marginal
LLWS is possible early this morning from KRDU northeast through
09Z, but confidence was too low to include in the TAF.

Outlook: A period of MVFR cigs are expected around daybreak Friday
morning across the northeast including KRWI and perhaps KRDU. An
approaching cold front will trigger scattered showers and
thunderstorms Friday afternoon into Saturday morning with sub-
VFR cigs/vsbys. Another round of sub-VFR conditions is possible
Sunday into Monday as a wave of low pressure travels along the
front that will stall to our south. -Blaes

&&

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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Badgett
SHORT TERM...MWS
LONG TERM...Luchetti
AVIATION...Blaes