498
FXUS62 KRAH 030452
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
1250 AM EDT Fri May 3 2024

.SYNOPSIS...
An upper level high pressure ridge extending over the area this
morning will shift to our southeast later today, as a surface
backdoor front drops into northeast North Carolina, before stalling
out and holding over the state through Saturday. A series of weak
upper level disturbances will move through the region from late
today through Sunday, bringing periods of unsettled weather.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 845 PM Thursday...

Little change to the going forecast for the rest of tonight. The Mid-
level ridge will remain anchored in place, although some energy from
the Mid-Mississippi valley and OH valley will reach portions of
eastern TN, increasing some high clouds toward daybreak. The main
forecast challenge will be if we see fog like we did yesterday, and
if so, where. Dewpoints mixed out into the low to mid 50s in most
places, indicating the dry air in place. However, observations and
model forecasts indicate these dewpoints rising into the low to mid
60s overnight with the inland sea-breeze. Dewpoints are already in
the mid 60s over some parts of the southern Coastal Plain. So there
could be some potential for some shallow fog beneath the drier air
and inversion that develops. However, most guidance keeps the best
chance over far SE NC. The best chance appears over the eastern
Sandhills to southern Coastal Plain, where dewpoints are expected to
be higher. Lows were raised a degree or two given the expected weak
moist advection. Lows to range from 57 to 64.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 230 PM Thursday...

A convectively enhanced disturbance over the Ohio Valley Fri morning
will largely remain to our west and north as it rides through the
western periphery of the high amplitude ridging along the East Coast
through the Great Lakes. At the surface, a lobe a high pressure will
ridge south through the Northeast and down the Mid-Atlantic coast
during the daylight hours. This should effectively push a shallow
backdoor cold front combined with the seabreeze through southeastern
VA into the northern Coastal Plain of central NC Fri evening before
stalling overnight. 12z Hi-Res guidance hints at some isolated
shower potential early Fri afternoon over the Piedmont, but limited
instability, dry air aloft, and a deeply mixed boundary layer will
likely prevent much outside of towering cumulus and an isolated
shower.

Otherwise, a very similar airmass will be in place with marginally
cooler 850mb temperatures compared to Thurs and would result in
highs in the upper 80s to around 90. Thickening mid/high clouds and
bubbling cumulus during the afternoon may keep temperatures in the
Triad closer to low/mid 80s. Underneath a blanket of cloud cover
overnight, lows will be more uniform across the area with lows in
the low/mid 60s.


&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 220 PM Thursday...

The first half of the extended forecast will feature an unsettled
pattern. A weak surface low will be over the Ohio River Valley
Saturday morning, slowly move to the east over Virginia by Sunday
morning, then dissipate. A cold front will extend to the south from
the low, and the front will be the primary rain-maker over the
weekend. Extended likely pops a bit farther to the east both
Saturday and Sunday. Rainfall amounts will range from a quarter inch
in the southeast to nearly an inch in the northwest - needed
rainfall, but not enough to change the drought status (almost all of
which is D0 - abnormally dry - in our area). All locations will have
at least a slight chance of thunderstorms, although instability
values will be a little higher in the west. After the upper 80s and
lower 90s of today and tomorrow, highs will be more seasonable for
the weekend, ranging from the upper 70s the mid 80s.

An upper level trough will approach the area Monday and move
overhead Tuesday, bringing a chance of showers and thunderstorms to
all locations. The forecast should then generally dry out for the
middle of the week. However, an upper ridge will build across the
Carolinas, and with southwesterly surface flow, temperatures will
rise above normal again. By Wednesday and Thursday, highs should be
in the lower 90s with lows around 70, values more typical of July
and August than early May.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 1250 AM Friday...

Except for a chance of MVFR vsbys/cigs in the SE including FAY 08z-
12z this morning, VFR conditions are likely to hold through at least
this afternoon across all central NC terminals, but with gradually
increasing high and mid clouds. Starting after 21z, an upper level
disturbance along with daytime heating will prompt isolated to
scattered showers and a few storms pushing into the west (INT/GSO),
with these chances lasting through the overnight hours, however VFR
conditions will still be dominant. However, starting after 04z
tonight, a backdoor front dropping into far N and NE sections will
bring a good chance for IFR cigs and MVFR to IFR vsbys into northern
areas, along and behind the front. However, these adverse aviation
conditions should hold N of the primary terminals until after the
end of the TAF valid period at 06z Sat.

Looking beyond 06z Sat, as the backdoor front settles southward well
into central NC, sub-VFR cigs/vsbys are expected to spread south
through most of the area 06z-12z Sat. As the front slowly lifts back
north and washes out, conditions will slowly improve back to VFR Sat
from SE to NW, with the Triad (INT/GSO) remaining sub-VFR well into
the afternoon. But the chance for sub-VFR conditions within
scattered to numerous showers and storms will be high, especially at
INT/GSO/RDU, Sat through Mon, particularly each afternoon and
evening, with locally gusty winds in and near storms, and a chance
for patchy early-morning fog areawide. -GIH

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Kren
SHORT TERM...Swiggett
LONG TERM...Green
AVIATION...Hartfield