Turner Downs Forecast Discussion

000
FXUS62 KRAH 241855
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
255 PM EDT Thu Jun 24 2021

.SYNOPSIS...
High pressure will extend down through central North Carolina as it
pushes off the Northeast coast through early Friday. A strengthening
flow from the southeast will bring increasing clouds, humidity,
and daily chances for showers and storms from late Friday through
the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 235 PM Thursday...

The morning clouds have decreased this afternoon as drier air in the
upper reaches of the mixed layer has advected in from the NE. These
fair skies should hold through this evening, but will be followed by
increasing clouds overnight from the SE. The mid level shear axis
extending through central NC will continue to diminish within the
weakening E CONUS trough. Another shear axis now evident on WV
imagery sitting just off the Southeast coast will drift
northwestward through tonight, nudged by the expanding mid level
ridge over the NW Atlantic. This will be accompanied by an inverted
surface trough marking the SE boundary of the narrow and weakening
ridge extending into central NC from the NE. As both this inverted
surface trough and mid level shear axis shift NW, with the former
moving ashore on the Carolina coast late tonight, clouds will
increase from the SE to NW with lowering bases as the moist upglide
atop the waning wedge increases and deepens with increasing long-
fetch SE flow just aloft. Expect a SE to NW trend to mostly cloudy
skies along and SE of the Hwy 1 corridor, with skies becoming partly
cloudy in our NW. Increasing dewpoints, especially along the inland-
moving coastal trough, will mean warmer temps than in recent nights.
Expect lows from the mid 50s NW to SE mid 60s. -GIH

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 255 PM Thursday...

Deeper moisture and higher PW air over the eastern Carolinas early
in the morning will expand toward the NW through Fri, with the
coastal inverted trough continuing a northwestward push and gradual
dissolution as the remaining neutral to stable surface-based layer
gets overtaken by warm/moist advection just aloft, by a broad area
of long-fetch Atlantic moisture. Enhanced moist upglide along this
retreating and diminishing frontal zone will likely provide a focus
for scattered inland-moving showers with isolated storms and an
increasingly tropical environment. The mid and upper levels however
are expected to remain somewhat dry, especially NW of the Hwy 1
corridor, and this will limit storm coverage as forecast CAPE
remains marginal over all but the coastal areas of NC. Will trend
pops up to scattered SE to NW through the morning and afternoon
(primarily scattered showers with isolated storms), with coverage
lowest across the NW. (We may also see the high cloud canopy from
upstream MCS activity drift overhead Fri, resulting in reduced
insolation and limited fuel for convection, esp in the NW.) As the
waning inverted trough shifts to the NW Piedmont with loss of
heating in the evening, shower coverage should decrease further, and
expect a trend to isolated showers in the far NW only by midnight.
We may see a resurgence of inland-tracking showers in our extreme SE
toward Sat morning as the just-offshore mid-upper level shear axis
sharpens and continues a drift to the NW into the eastern Carolinas,
but for now will keep any pops there low. Expect highs from around
80 to the mid 80s and by lows in the mid 60s to around 70. -GIH

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 250 PM Thursday...

The primary feature in the extended forecast will be an upper level
high sitting off the East Coast of the United States. The high will
strengthen through the period, reaching its peak strength around
Tuesday afternoon before beginning a slow weakening trend. The
building heights will help to suppress thunderstorm development,
although there will be at least a slight chance of showers/storms
every day through the forecast.

Sunday and Monday appear to be the driest days through the extended
forecast, with any precipitation coverage following a diurnal curve
with greatest coverage in the afternoon and evening and much less
coverage overnight and in the morning. After slightly below normal
highs on Saturday, expect near normal temperatures around 90 degrees
through the week. Similarly, forecast lows will be near 70 degrees.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 150 PM Thursday...

VFR conditions are expected across central NC until at least
midnight. But starting after midnight, winds through the lowest
several thousand ft AGL shift from light out of the NE to be from
the E and SE, drawing increasing amounts of Atlantic moisture into
the area from SE to NW. This will result in a trend of cigs to MVFR
from SE to NW over all but the NW (INT/GSO) from 07z to 14z, and
after 14z all central and eastern terminals are likely to have MVFR
cigs, although vsbys should stay VFR. A few sprinkles or showers
will also accompany these MVFR clouds, first in the predawn hours at
FAY then shifting northwestward into RDU/RWI through Fri morning.
Surface winds will stay mostly from the NE, 8-12 kts through mid
afternoon with infrequent gusts to 15-20 kts this afternoon, before
becoming light under 8 kts from the NE starting early evening and
continuing through Fri.

Looking beyond 18z Fri, the morning MVFR-based clouds in the E will
track slowly westward into the western terminals (INT/GSO) in the
afternoon while also slowly lifting, and cigs may briefly become low-
end VFR areawide before nightfall. We`ll see scattered showers and
isolated storms Fri afternoon, diminishing Fri evening with areas of
sub-VFR cigs again late Fri night. As we get into a warm/humid
pattern, this cycle of isolated to scattered showers and storms in
the afternoon through early evening, followed by sub-VFR cigs each
late night/early morning, will continue through Tue. -GIH

&&

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

&&

$$

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

NWS RAH Office Area Forecast Discussion