116
FXUS62 KRAH 031042
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
645 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/...
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

&&

.LONG TERM /SUNDAY THROUGH THURSDAY...
As of 250 AM Friday...

...Elevated Rain Chances Will Linger Through Monday...

...Heat Returns Middle Part of Next Week...

Sunday and Sunday night: The stalled sfc front sagging across
northern portions of the forecast will retreat north early Sunday,
leaving all of central NC in the warm sector. Subtle upper
disturbances coupled with the development of weak to moderate
buoyancy during the afternoon will act upon the elevated PWATS (150-
160% of normal)in place over the region to support afternoon showers
and storms. Shear is generally less than 20 kts, so the threat for
organized severe storms is near zero.

The moist PWATs and associated mostly cloudy skies and rain chances
should temper afternoon temps. Highs in the upper 70s north to lower
80s.

Convection should largely dissipate as BL nocturnally cools and
stabilizes. Under mostly cloudy skies, mild overnight temps in the
60s.

Monday and Monday night: A compact shortwave trough over the Mid MS
Valley will become increasingly sheared as it crosses the central
and southern Appalachians Monday afternoon and through the Mid
Atlantic States Monday night.  PWATs are forecast to increase to
~200% of normal as the trough and associated DPVA moves through the
area.  As such, expect another healthy uptick in diurnal coverage
and PoPs Monday afternoon and into the evening. Shear remains weak.
Thus, the threat for severe storms remains low. Low-level
thicknesses are on par or slightly higher than Sunday. Highs 80-85.
Lows in the 60s.

Tuesday through Thursday: Rain chances will lessen during this
period, with weak disturbances moving atop the ridge providing the
primary focus for scattered shower and storms, mainly across
northern portion of the forecast area. The main weather headlines
will be the return of the heat during the second half of the work
week. Highs Wednesday and Thursday are expected to top out in the
mid/upper 80s north lower 90s over interior and southern portions of
the forecast area. Expect very warm nights as well, potentially
record warm, with lows 65 to 70.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
As of 645 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. As the backdoor front settles
southward well into central NC overnight, sub-VFR cigs/vsbys are
expected to spread south through most of the area 06z-12z Sat, with
scattered showers.

Looking beyond 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...CBL
AVIATION...Hartfield