051
FXUS62 KRAH 011834
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
234 PM EDT Wed May 1 2024

.SYNOPSIS...
Weak high pressure will build over the Carolinas and Southeast this
evening through Friday, resulting in very warm temperatures. A
series of weak upper level disturbances will move through the region
Friday evening through Sunday, bringing periods of unsettled
weather.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 230 PM Wednesday...

A compact shortwave has shifted off the NC coast as of 17z
mesoanalysis data with shortwave ridging and subsidence inversion
building behind in its wake. At the surface, a pressure trough and
moisture axis continues to slowly sag through central NC and
currently stretches from north of Elizabeth City, southeast of
Raleigh, and through Mackall Army Airfield near Scotland County. Dew
points across central NC have been sufficient to produce widespread
afternoon cumulus clouds, but the rich moisture east of the pressure
trough characterized by dew points in the low/mid 60s, is where 500-
1000 J/kg of MLCAPE and isolated showers have begun to develop.

The most persistent cluster is located in the vicinity of
Fayetteville and have so far struggled to gain sufficient depth/size
to produce much lightning given the abundant dry air aloft.
According to SPC Mesoanalysis, better 700mb moisture exists on the
backside of the departing shortwave and +1000 J/kg of MLCAPE in
eastern NC has resulted in more efficient updrafts and showers to
deepen into storms. This storms and the outflows they produce may be
what is required to see scattered showers and isolated storms to
develop in the vicinity of the I-95 corridor through the
afternoon/evening. Effective shear of 15-20 kts would result in
mostly pulse storm mode and clusters developing along common cold
pools. Sub-severe winds and cloud to ground lightning would be the
primary hazards if any storms are able to sustain themselves into
our forecast area.

Shallow moisture advection tonight behind a seabreeze into the
Coastal Plain and Sandhills may result in patchy fog development
with clear skies and calm surface conditions. Moisture depth will be
a limiting factor for seeing areas of fog and would rely heavily on
strong radiational cooling to cool the surface below the upstream
crossover temperature. Lows tonight will range mid 50s to low 60s.
Low 50s will be possible in the typical cool spots.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 220 PM Wednesday...

The weather should remain quiet on Thursday with a weak surface high
over the region. A weak upper level ridge should also build across
the Carolinas, limiting overall sky cover. The primary exception to
that should be the development of a sea breeze along the coastline,
which should push some scattered diurnal cumulus clouds across
southeastern counties during the afternoon. In addition, some high
clouds should begin to move in from the west late Thursday night.
Mid to upper 80s are forecast for Thursday, with an isolated 90
degree reading possible. Rising heights should also allow for warmer
overnight lows, generally in the low to mid 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 350 AM Wednesday...

Unsettled weather expected over the weekend into early next week,
but confidence in the timing of possible showers and storms, as well
as total rainfall amounts remains relatively low .

A strong ridge over the southeast US will slowly shift east and
offshore by Saturday, allowing weak height falls aloft and the
passage of a series of weak shortwaves in more moisture-favorable
west-southwest flow aloft.

At the surface high pressure over eastern Canada will extend through
New England and nudge a backdoor cold into northeastern North
Carolina by Saturday morning, while a surface low migrates through
the Ohio Valley and its trailing weak cold front advances east into
the Appalachians by Sunday.  The weak front may not actually make it
into NC, but the presence of disturbances aloft along with
precipitable water increasing to over 1.5 inches should result in
scattered to numerous showers and a moist and less capped warm
sector, augmented by diurnal heating and instability, and the timing
of the disturbances.  A limiting factor in the coverage of precip
may be the absence of greater larger scale forcing and increased
cover/reduced instability as highs are expected to drop back into
the upper 70s and lower 80s.

The best time for precip appears to be late Saturday through Sunday,
though the models appear to be trending at least slightly wetter for
Monday and Tuesday as well.  All-in-all, near normal rainfall of up
to one inch is possible across the area, but the pattern doesn`t
appear to favor much more than that on the whole.  After the brief
relative cool down, upper 80s look to return by midweek next week

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 120 PM Wednesday...

An area of agitated cumulus in the vicinity of FAY has been
producing brief showers that redevelop along a prior showers outflow
for the past hour. So far, the dry air aloft has prevented enough
hydrometeors at or above -10C and have been void of lightning so far
this afternoon. Regional satellite has shown some glaciation on the
tops of a couple updrafts, so isolated lightning can not be ruled
out through the afternoon. Cumulus clouds in the vicinity of RWI
have remained flat and shallow which has prompted the removal of the
tempo in favor of a period of VCSH. Shallow moisture advection
behind the seabreeze may result in patchy fog affecting the Coastal
Plain (FAY/RWI) with less confidence on impacts at RDU. Fog/stratus
will quickly clear after daybreak with light winds generally out of
the southeast through the afternoon with scattered fair weather
cumulus.

Looking beyond 18z Thu, VFR conditions will prevail through Fri. The
chance for sub-VFR conditions within scattered to numerous showers
and storms will increase starting Fri night, lasting through Sun, as
a series of disturbances passes over the region. Areas of early-
morning fog are also expected. -GIH

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Swiggett
SHORT TERM...Green
LONG TERM...BLS
AVIATION...Swiggett/Hartfield