367
FXUS62 KRAH 280549
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
149 AM EDT Fri Jun 28 2024

.SYNOPSIS...
High pressure will move off the New England coast today and tonight.
A hotter and more humid airmass will become established across
the area this weekend. A cold front will approach the area late in
the weekend.

&&

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

Evening surface analysis shows a few boundaries worth noting to
influence our weather for the rest of the night. The first is a
loosely defined boundary that pushed through today and currently
resides along far eastern NC and stretches into central SC, northern
GA and connecting to a weak area of low pressure over central AL.
This front does not have much of a temp/dewpoint change, mainly just
a wind shift. The surface low in AL is also present as a trough at
mid-levels and will continue to circulate over the deep south
overnight before weakening later Fri morning/afternoon. This trough
to our SW could keep mid clouds across the southern Piedmont,
Sandhills, and southern Coastal Plain for several hours before
slowly dissipating. A few isolated showers cannot be ruled out in
the southern Piedmont owing to some low-level lift and elevated
instability, but most CAMs are dry.

The second boundary has a more noticeable temp/moisture
discontinuity. Its location stretches from the the far NE US into
the lower OH valley and portions of MO/IL. Behind this boundary is
an area of high pressure over the Great Lakes. This high is forecast
to strengthen and reach eastern PA/NY by sunrise. That movement
should allow southward progression of the aforementioned boundary,
likely settling somewhere near the NC/VA border by Fri morning.
While these lower dewpoints are not expected to move through until
sometime Fri afternoon, recent runs of the HRRR suggest low stratus
or fog could develop with the approach of the front as moisture
pools along the boundary. Patchy fog may also be possible over the
Coastal Plain and eastern Sandhills, where dewpoints are higher and
rain did occur earlier today. Lows tonight will be in the upper 60s
to low 70s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
As of 345 PM Thursday...

High pressure across New England on Friday morning will shift
offshore on Wednesday allowing the lingering cold front across the
eastern Carolinas to lift north as a warm front on Friday. A light
northeast low level flow on Friday morning will veer to
southeasterly during the afternoon and continue into the overnight.
Surface dew points will range in the upper 60s to lower 70s to start
the day, they may mix out a bit toward midday but with the
southeasterly flow they will jump into the lower to mid 70s during
the afternoon and overnight. With the southeast flow expect a decent
amount of cloudiness and the potential for some widely scattered
convection during the afternoon and into the overnight with the
convection favored in an arc across the south and west.
Highs will be complicated by the amount of cloudiness but should
range in the upper 80s near the VA border and Triad and the lower
90s in most other locations. Maximum heat index values will
range in the 90s to around 100. Lows Friday night will be warm
and muggy with the clouds and southeast flow with lows of 70-75.
-Blaes

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 350 PM Thursday...

This above-normal temp stretch will hit yet another crescendo this
weekend, with convection chances peaking Sun/Sun night. A brief temp
respite arrives early next week, however this will quickly give way
to a return to excessive heat midweek.

Sat-Sun night: Well above normal temps and high dewpoints return
Sat, as low level thermal ridging and and warm/stable mid levels
spread in from the W and WSW. A potent northern stream shortwave
trough swings through the upper Midwest and N Great Lakes Sat but
the main band of westerlies holds N of NC, leaving us within a
regime of light steering flow. Weak surface troughing will be in
place through the Piedmont, but a loose low level height field
yielding weak low level flow will limit any low level mass
convergence. As such, any storms Sat are apt to be weakly forced and
more pulse-type, focusing on subtle boundaries and the sea breeze.
PW will be rebounding Sat, with model projections of values surging
over 2" through the NC Piedmont, so expect scattered late-day
coverage despite the lack of a focus or strong mechanism to force
ascent. Thicknesses and surface dewpoints will rebound as well,
supporting highs Sat in the low-mid 90s and heat index values of 100-
105 in all but NW sections. By Sun/Sun night, the mid level trough
will dig positively and somewhat strongly over extreme SE Canada and
the St Lawrence Valley into the Northeast, with a corresponding
strengthening in cyclonic mid level flow over our area as the
attendant surface cold front approaches late in the day. Low level
thicknesses rise to 10-15 m above normal ahead of the front with
surface dewpoints also likely to be quite high, well into the 70s
with only modest afternoon increases given low level moisture influx
ahead of the front. Sun is likely to be another day of dangerous
heat, with highs mostly in the mid 90s and heat indices again around
100-105 over most of the area. Sun should have the highest rain
chances, as most deterministic models show PW rising to highly
anomalous values around 2.5" along with moderate SBCAPE and decent
(but still less than ideal) deep layer bulk shear. Will continue
with a period of likely pops Sun afternoon and evening, extending
into the overnight in the S.

Mon-Thu: The front will settle to our S for Mon/Tue with high
pressure nosing in from the N, resulting in mostly dry weather
(except for pops in the S Mon, a nod to a possible slower frontal
progression). The mid level trough extending down through the Mid
Atlantic early Mon will shift offshore by Tue as ridging aloft
builds anew from the S Plains/Lower Miss Valley, so expect the
mostly dry weather to persist through mid week at least. As the
surface ridge pushes out over the open NW Atlantic by Wed, the
oppressive heat will return. After near normal highs and gloriously
low dewpoints in the 60s Mon/Tue, we should see highs in the mid-
upper 90s return for Wed and July 4th, with very low chances for
showers and storms. -GIH

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 149 AM Friday...

Generally VFR conditions are expected through 06z/Sat.

Outlook: Sub VFR conditions will be possible area-wide Sat-Sun
mornings with IFR stratus, followed by a good chance of mainly
afternoon-evening showers/storms Sunday. VFR conditions are expected
early to mid week next week.

&&

.CLIMATE...
Record High Temperatures:

June 30:
KFAY: 102/2012

Record High Minimum Temperatures:

June 28:
KGSO: 76/1969
KRDU: 76/1952
KFAY: 78/1914

June 29:
KGSO: 74/2010
KRDU: 78/1914
KFAY: 76/1969

June 30:
KGSO: 74/1936
KRDU: 80/1936
KFAY: 79/1936

July 1:
KGSO: 77/1970
KRDU: 75/2012
KFAY: 76/1990

&&

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

&&

$$

SYNOPSIS...Badgett
NEAR TERM...Kren
SHORT TERM...Blaes
LONG TERM...Hartfield
AVIATION...Badgett/Luchetti
CLIMATE...RAH