-- Discussion containing changed information from previous version are highlighted. --
388
FXUS62 KRAH 030625
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
225 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. A surface backdoor
front will drop into northeast North Carolina tonight then stall
out, holding over North Carolina through Saturday before slowly
washing out. A series of weak upper level disturbances will move
through the region from late today through Sunday, bringing periods
of unsettled weather.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 150 AM Friday...

A last largely dry day before we start trending wetter, esp W. Very
weak surface troughing sits over the W Piedmont of NC currently,
capped by the mid-upper level ridge axis extending over the central
and eastern Carolinas. PWs remain on the low side, under 1" except
in our far S (where there is a risk for some stratus and fog for a
few hours early this morning). With stable and dry mid levels, we`ll
again be dry today, albeit with increasing high then mid level
clouds, along with a few high-based afternoon cu, as a mid level
perturbation/remnant MCV currently over the Mid South shifts
eastward into our area. Low level thicknesses will again be well
above normal, with models showing values several meters higher than
yesterday when we reached the upper 80s to lower 90s. The gradual
increase and thickening of clouds will curb heating slightly, but we
should still be able to reach the upper 80s to around 90, perhaps a
few lower 90s east, close to but generally below record highs (see
climate section below).

As the steadily dampening wave shifts E of the Appalachians, clouds
will continue to spread in tonight from the W, with PWs near or
above 1.5" spreading into at least the Piedmont and Sandhills. CAPE
is minimal and elevated, and the flattening wave and weak mid level
flow will provide little in the way of dynamic forcing for ascent.
but the deepening moisture and a couple hundred J/kg will be enough
to support isolated to scattered showers and perhaps a storm
overnight, in the Triad this evening then spreading into the rest of
the Piedmont after midnight. In addition, models are in good
agreement that the backdoor front now stretching across the Mid
Atlantic region will continue to push southward into our area late
tonight, bringing an area of stratus spreading in from the N and NE,
and increasing low level mass convergence along this backdoor front
may prompt additional light rain areas in its vicinity. Lows from
around 60 the mid 60s. -GIH

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
-- Changed Discussion --
As of 225 AM Friday...

Confidence is high on increasing chances for showers and a few
storms, although no one will see rain the entire day, and
pinpointing the location and motion of what should be shower/storm
clusters is challenging. PWs will continue to rise, with models
indicating a swath of 1.5-1.75" values surging up through central
NC, in the 90th percentile and even nearing daily records. This will
occur in tandem with increasing low level moisture flux drawing
Atlantic moisture into our area. As the backdoor front settles
further into the area Sat morning, followed by a very gradual
weakening and washing out, the considerable stratus over much of the
area, esp N and W sections, will hinder heating and destabilization
until it retreats and breaks up later in the day. And our large
scale dynamic forcing for ascent will be poor, given the weak mid-
upper level flow, but we may still feel the effects of MCVs
emanating from today`s Plains convection as it shifts into our area
late Sat through Sat night. All of this supports scattered to
numerous clusters of showers and storms, particularly in areas W of
I-95 where moisture will be deepest, with the highest pops in the
Triad and perhaps a secondary focus along the weakening backdoor
frontal zone. The storm threat will be limited, given the weak deep
layer bulk shear and modest CAPE, but a few storms will remain
possible mainly in the afternoon and evening. Rain chances will
persist overnight with further moistening of the low levels with
confluent 925 mb southerly flow strengthening to 15-25 kts with both
Atlantic and Gulf taps. While areally averaged rainfall amounts
aren`t likely to be high, given the anomalously high PW and somewhat
slow storm motion with cell mergers possible, isolated areas could
see local rainfall totals that could present minor urban flooding
issues, esp in the Triad region, despite the recent dry weather.
With mostly cloudy to cloudy skies, expect highs from the mid 70s N
and W to lower-mid 80s SE. Lows in the 60s. -GIH
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY 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

&&

.CLIMATE...

Record High Temperatures:

May 3:
KGSO: 92/1959
KRDU: 93/1959
KFAY: 95/1913

Record High Minimum Temperatures:

May 4:
KGSO: 65/2022
KRDU: 68/1938
KFAY: 68/1942

&&

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

&&

$$

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