499
FXUS62 KRAH 140745
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
345 AM EDT Fri Jun 14 2024

.SYNOPSIS...
An area of low pressure will move northeast just off the Carolina
coast through tonight. A cold front will move southeast across NC on
Friday night and into SC and GA on Saturday where it will stall and
linger through the weekend. The front will lift north through the
area as a warm front on Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 315 AM Friday...

The latest surface analysis shows an elongated low pressure system
organizing off the GA coast early this morning in the vicinity of a
lingering frontal zone. A small and narrow area of high
pressure extends from southeastern VA southwest into southern
NC. In addition, a cold front extends from Lake Ontario
southwest to near KORD and KSTL. The air mass across central NC
has moistened up over the past 24 hours with PW values of around
1.0 to 1.3 inches, close to normal.

A rather vigorous shortwave trough will move from the Great Lakes
this morning to New England late tonight with central NC well
removed from the forcing for ascent with this feature. The
associated cold front will drop southeast across the central
Appalachians late this afternoon and into northern NC this evening
before moving south into southern NC by around daybreak Saturday.
With the absence of deep moisture and forcing for ascent, NWP
guidance only generates a few showers and possibly a storm across
southern VA this afternoon with the convection fading as it moves
into north-central NC. Instability is lacking with the atmosphere
becoming only weakly unstable in central NC this afternoon with
forecast soundings highlighting a narrow CAPE distribution. It`s
worth noting that the greatest instability although limited is
across the Foothills and western Piedmont where the mid levels are
slightly cooler with very little instability to the east near the
coast. In addition, the latest CAM runs show less convective
coverage than the runs 12 hours ago. With this pattern, have opted
to include a slight chance of about 15% of a shower or a storm
across the northern Piedmont this evening.

The latest NWP guidance is rather consistent in forecasting low
level thickness values of 1400 to 1405m this morning, which is
about 5 to 12m warmer than on Thursday which results in highs
about 2 to 4 degrees warmer than Thursday afternoon. This should
translate to highs of 91 at KGSO, 93 at KRDU, and 94 at KFAY
which is about 3 to 7 degrees above average. Dew points this
afternoon should range in the lower 60s which should keep heat
index values close to the high temperatures. Lows tonight will
be a little warmer than previous nights and range in the upper
60s to lower 70s. -Blaes

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 340 AM Friday...

A northwest flow aloft is expected on Saturday and Saturday night as
the trough moves off the Northeast coast and a mid level ridge
develops across the Southeast centered near northern GA/AL. At the
surface, a cold front will be moving south across southern NC during
the morning and then into northern SC and GA. While drier air will
move into northern parts of NC on Saturday, the air mass across
southern NC will remain warm with low level thickness values
actually warmer than today across the south with thickness values of
around 1415m near the SC border and around 1395-1400m near the VA
border. This will translate into highs of 92 to 95 across southern
NC with cooler highs of 86 to 89 near the VA border. With cooler
temperatures aloft and a warmer boundary layer, the atmosphere
becomes moderately unstable across southern areas on Saturday
afternoon. This may support an isolated thunderstorm across southern
and southeast areas in proximity to the front and the inland
advancing sea breeze although NWP guidance generally lacks much of
precipitation. Lows on Saturday night will be a little cooler than
the previous night and range near average with lows near 60 near the
VA border to the mid 60s across the south. -Blaes
&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 200 PM Thursday...

The leading edge of a surface cold front will be working through
central NC Sat morning and is forecast to be draped across the
southern/central Coastal Plain into the Sandhills by 12z Sat. This
boundary will mark the delineation between continued warm/moist
airmass to the south and gradual theta-e drop to the north. The
timing of the front still is uncertain with the slowest guidance
(NAM and NAM3km) keeps the front in the forecast area through the
early afternoon. Available Hi-Res guidance suggest a moderately
unstable (1000-2000 J/kg MLCAPE) and weakly sheared (15-20 kts of 0-
6km shear) environment could be in place south of this front. If
this scenario does develop, the best coverage of showers/storms
would be mostly confined to the southern Coastal Plain and eastern
Sandhills where proximity to the front and potential seabreeze
collision would be most probable. Storm motions will by towards the
ESE to SE so any storms the develop should quickly move away from
the forecast area. Temperatures will be tricky and tied to the cold
fropa, but current forecast suggest mid 80s (N) to low 90s (S).

An anomalous mid/upper level anticyclone will drift from Lower MS
Valley over central NC Sun through Tues before strengthening further
as it shifts over the Northern Mid-Atlantic and Northeast through
Thursday. Warm and dry mid-level temperatures and surface high
pressure ridging into the area from the northeast will suppress
convection over much of the forecast area. Only chances will likely
be confined to upslope induced convection over western NC that may
leak into the western Piedmont Sun with NW steering flow. Deep layer
flow shifts out of the east Tues onward and keeping upslope flow
pinned to the NC mountains. Temperatures through the remainder of
the extended will be fairly consistent in the upper 80s to low/mid
90s for highs and lows in the 60s.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
As of 245 AM Friday...

24 hour TAF period: VFR conditions are generally expected across
central NC through the 24 hour TAF period with a couple of localized
exceptions. Some very patchy, mainly MVFR fog is possible early this
morning through around daybreak, especially in the Coastal Plain and
eastern Piedmont. There is also a very limited threat of a shower
this evening, primarily across the north, as a cold front approaches
the area. Otherwise, VFR conditions are expected with a mix of some
cirrus clouds and SCT late morning through evening cumulus clouds.
Light winds are expected today with winds from the north and
northeast across eastern locations at KFAY and KRWI while light
mainly southwest winds are expected to the west at KINT/KGSO/KRDU.
Winds will veer around to southwesterly across the area late this
afternoon with winds shifting to north late tonight across the north
as the cold front moves through the area.

Outlook: A cold front will shift south of central NC on Saturday
morning with winds shifting to northerly and then easterly on
Sunday. Generally fair weather is expected into early next week
although some late night and early morning stratus and fog is
possible, mainly across the western and southern Piedmont
areas around daybreak on Sunday through Tuesday. -Blaes

&&


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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Blaes
LONG TERM...Swiggett
AVIATION...Blaes