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000
FXUS62 KRAH 271721
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
120 PM EDT Sat Apr 27 2024

.SYNOPSIS...
An upper level ridge will remain over central NC through Monday.
Surface high pressure will continue ridging into central North
Carolina as it slowly slides south along the mid-Atlantic coast
through Sunday. The surface high will settle off the Southeast
United States Sunday night and Monday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 940 AM Saturday...

Lower clouds have not developed this morning in the Triad, and in
fact, some partial clearing is creeping into southwestern portions
of the forecast area, although most locations remain under a mid
level overcast. Not much change was needed with the morning update.
Previous discussion follows.

As of 300 AM Saturday...

The upper level ridge will amplify as it shifts eastward over the
region through this morning. The ridge will remain over central NC
through tonight. At the surface, high pressure will remain SSE of
Long Island today, then slowly slide southward off the mid-Atlantic
coast tonight. While the high will generally ridge into central NC
today, as it slides southward sely return flow will advect
relatively warm, moist air into the area off the Atlantic, pooling
over the Foothills and western Piedmont tonight. Some model guidance
is still hinting at a period of increased isentropic lift, mainly
over the northwest Piedmont through this morning, which could result
in a period of low clouds developing over the Triad. As sely flow
increases this afternoon, some low/mid clouds may develop over the
southern Coastal Plain and drift nwwd through late aft/early eve.
Cannot rule out a stray sprinkle/shower, but chances are low so for
now will keep the forecast dry. Highs today should range from around
70 degrees NE to mid/upper 70s SW. Lows tonight in the low to mid
50s expected.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 330 AM Saturday...

Warm(ing) and dry.

A ~319 dam 700 mb anticyclone will be directly over the Carolinas
and within a highly amplified mid-level ridge that will remain over
the ern US through the weekend. Associated subsidence will
contribute to the strengthening and maintenance of a subsidence
inversion that will cap a shallow, diurnal, and high-based
stratocumulus layer on Sunday, followed by mainly clear Sunday
night.

At the surface, a modified Canadian high will become situated off
the coast of the Carolinas, just downstream of the aforementioned
ridging aloft, with associated sswly flow directed across cntl NC.
High temperatures will consequently warm into the upr 70s-lwr 80s,
but with comfortable humidity levels in the 30-40th percentile owing
to the continental influence of the surface high. Low temperatures
Mon morning will be in the 50s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 400 AM Saturday...

A slowly progressive, high amplitude ridge in the mid-levels will
drift across and offshore the South and Middle Atlantic through
early Tuesday, downstream of a convectively-amplified shortwave
trough that will progress through the region late Tue-Tue night.
00Z/27th model guidance has trended toward a stronger/more-amplified
trough as it moves across the srn Middle Atlantic, with 30-60
meter/12 hr 500 mb height falls, Tue night. The models depict, in
the wake of that shortwave trough, a re-strengthening and
retrogression of mid-level ridging across the South Atlantic Wed-
Fri.

At the surface, high pressure off the coast of the Carolinas will
continue to extend wwd and across the Southeast Mon and Tue, ahead
of a pre-frontal/lee trough that will move across the srn Middle
Atlantic Piedmont and Coastal Plain Tue afternoon-night. Another
Canadian high, about 10-15 mb weaker than its unseasonably strong
predecessor now centered over srn New England, will build down the
Middle Atlantic coast mid-late next week. While its presence may
result in somewhat cooler and near-below average surface
temperatures along the immediate coast, areas inland, from the lwr
OH Valley and interior srn Middle Atlantic to the Southeast, will
remain warm and well above average, with daytime temperatures in
cntl NC well into the 80s throughout the week.

The relative best chance of rain/convection will result Tue
afternoon-evening, especially over the Piedmont where diurnal timing
of the aforementioned shortwave and surface troughs will be
maximized, then again Fri-Sat, as the next synoptic front/forcing
approach from the northwest. No appreciable or widespread rain is
expected throughout the week, however, so the combination of mainly
dry, and warm temperatures will likely exacerbate what will become
worsening Abnormally Dry to Moderate Drought conditions.

&&

.AVIATION /17Z SATURDAY THROUGH THURSDAY/...
As of 120 PM Saturday...

TAF period: High confidence in VFR conditions through the TAF
period. While some diurnal cumulus are expected this afternoon,
those clouds are not expected to form MVFR ceilings. Mid level
clouds are plaguing much of the eastern half of the state, but those
clouds are expected to scatter out this afternoon, just leaving high
clouds overnight. The wind will have a southerly component
everywhere, with an easterly component across eastern terminals and
a westerly component across western terminals. The wind will veer at
all sites overnight, but only included another FM group for RDU
Sunday morning.

Outlook: As is usual, the NAM soundings are a little more aggressive
showing low VFR clouds Monday and Tuesday mornings than the GFS
soundings, but do not think this will amount to any ceilings. The
primary chance for showers/thunderstorms in the extended forecast
will be on Tuesday.

&&

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

&&

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