460
FXUS62 KRAH 040620
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
220 AM EDT Sat May 4 2024

.SYNOPSIS...
A backdoor cold front will settle into north-central North Carolina
tonight, where it will stall through Saturday night, then weaken and
move northward into Virginia on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 835 PM Friday...

A backdoor cold front has moved into the extreme northeastern
portion of the forecast area - KIXA had a wind shift from southerly
at 6pm to easterly at 7pm. In addition, several sites across
southeastern Virginia and northeastern North Carolina have had a
shift to easterly wind with much cooler temperatures. Meanwhile, an
area of showers and thunderstorms is moving to the north out of
Person County, with an area of showers extending farther to the
south where a differential heating boundary developed earlier.

The chance for showers and thunderstorms should diminish through the
evening, then rise again overnight as the back door front moves
farther into the area. The location of the front and just how far
southwest it moves could have a significant impact on overnight
temperatures. The current forecast calls for temperatures in the
low 60s across the northeast to the mid 60s in the southwest. In
addition, an area of low stratus appears likely to move in behind
the front.
&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 230 PM Friday...

Aloft, the sub-tropical ridge will stall along the eastern seaboard
through Sat night. A southern stream disturbance will move into the
Southeast US on Sat, then lift newd through the area as a sheared
out northern stream s/w moves through the OH Valley/Great Lakes Sat
night. The sub-tropical ridge will shift offshore and breakdown
Sun/Sun night as the disturbances move through the mid-Atlantic and
Northeast US. Another southern stream s/w will develop over the
southern Plains on Sun, then move eastward into the lower/mid-MS
Valley Sun night. At the surface, as high pressure sits over the New
England coast, the backdoor cold front is expected to stall over
nrn/nern NC through Sat and into Sat night then lift northward late
Sat night/Sun. The high should move eastward over the Atlantic as a
low moves through the Great Lakes and into the Northeast Sun/Sun
night.

Precipitation/Convection: Still fairly high confidence/chances for
showers and possible storms Sat and Sun. Best threat for storms will
be across the Piedmont, mainly along and south of the surface
boundary, where surface-based CAPE will be maximized. Bulk shear
still appears weak, and PWATs are expected to range from 1.4 to 1.8
inches. Do not expect the entire day to be a wash-out by any means,
and Sat could start dry for most, but there will be a chance for
showers across all of central NC, with greatest coverage from Sat
eve through Sun aft. Highest chances NW, lowest SE. Given the high
PWATs and scattered, somewhat disorganized mode of convection,
isolated locations could receive locally heavy rainfall, with any
potential for minor flooding issues largely limited to urban areas.

Temperatures: A bit tricky on Sat, as there is some bust potential
north of the front. Widespread overcast skies should somewhat limit
heating as well. For now expect highs to range from the mid 70s
along the NC/VA border to mid 80s SE. Sat night temps should be
continued mild, mainly in the low to mid 60s. On Sun, with the
retreat of the front northward, areas across the north may be a few
degrees higher than Sat, but given the expected showers/storms
through the day, temps may otherwise be limited. Highs in the upper
70s north to low 80s south.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 329 PM Friday...

The extended forecast upper pattern will largely include mid-level
ridging over the eastern US. A stronger short-wave will move over
the area Monday into Tuesday increasing rain chances. After
relatively zonal flow Tuesday, mid-level ridging will then re-
amplify over central NC through the end of the extended. Another
potentially stronger trough may approach late in the period.

Monday/Tuesday: A potent mid-level short-wave and associated
vorticity max is forecast to move across the southern Appalachians
Monday afternoon. Mid-level height falls will maximize over us later
Monday afternoon/early evening coinciding with peak
heating/instability. At the sfc, a piedmont trough will develop
Monday afternoon which, in combination with forcing aloft, should
help to focus showers and storms across our area.  Bulk layer shear
will be much too weak to support severe storms, but given the
presence of anomalous PWAT (150 to 200 % of normal) any storm that
develops could produce brief heavy downpours and gusty winds. POPs
should decrease late Monday night/early Tuesday morning as flow
aloft turns a bit more nwly and the atmosphere stabilizes.  In
absence of upper forcing aloft, rain chances Tuesday afternoon will
largely rely on diurnal shower/storm development which should remain
mostly scattered.

Temperatures Monday will peak in the mid to upper 80s, increasing
into the upper 80s by Tuesday afternoon.

Wednesday/Thursday: The mid-level ridge will re-establish itself
Wednesday and Thursday as temperatures soar into the lower to mid
90s. The NBM is particularly stoked about 90 temps for highs these
days with >80% of it`s members reaching this threshold for much of
this area. The LREF (GEFS, GEPS, EPS) is a little less enthused on
Wednesday, but does suggest decently high probabilities on Thursday
(generally 40 to 60 % across the area).

Otherwise, anomalous moisture will remain in place
Wednesday/Thursday which should promote a continuation of low-chance
POPs each afternoon.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
As of 220 AM Saturday...

A back-door cold front, noted by a E-NELY wind shift, will settle
south across the northern TAF sites over the next few hours before
stalling. Moisture pooling along the front should lead to the
development of IFR to MVFR ceilings at all TAF sites 08 to 12z.

Ceilings at KFAY, KRDU, and KRWI should gradually lift to VFR from
south to north through 17-18z, with scattered showers and storms
possible during the afternoon and evening, especially at KRDU.

At KGSO and KINT, ceilings could remain IFR to MVFR through the
afternoon and evening as intermittent showers and storms develop and
move through the area through much of the forecast period.

Showers will linger across the area tonight, with the re-development
of LIFR to MVFR conditions across the area, lowest at KINt and KGSO
where the deepest moisture resides. -CBL

Outlook: IFR-MVFR ceilings are likely to redevelop each night-
morning through Monday, as are scattered to locally numerous
showers/storms each afternoon-evening. -MWS

&&

.CLIMATE...

Record High Minimum Temperatures:

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

&&

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

&&

$$
SYNOPSIS...Green
NEAR TERM...Green
SHORT TERM...KC
LONG TERM...Luchetti
AVIATION...CBL/MWS