-- Discussion containing changed information from previous version are highlighted. --
787
FXUS62 KRAH 031850
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
250 PM EDT Mon Jun 3 2024

.SYNOPSIS...
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A series of mid level disturbances will move east across the area
through mid week, as a weak surface trough and unseasonably moist
air mass holds over the region. A cold front will approach from the
west Thursday and move across the area Friday, bringing drier and
less humid conditions for the weekend.
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&&

.NEAR TERM /THROUGH TONIGHT/...
As of 945 AM Monday...

As the current surface trough slowly moves across the region
scattered showers continue to move across the eastern portions of
the CWA this morning. Another round of lighter rain is moving across
the Triad area but dissipating as it moves south east. Made minor
changes to the PoPs today as rounds of precipitation is expected
through the day. While chances reduce to 15-25 % for a few hours
during the day, the afternoon chances increase to 25-35% when the
lee trough enters the NW Piedmont later today and moves across the
region this afternoon and evening. While clouds are expected to thin
out later this morning between the features, some areas could see
some sunshine and heating, in result, temperatures ranging around
the low to mid 80s today.

As of 400 AM Monday... Amid an unseasonably moist airmass
characterized by PWs around 1.5" (~90th percentile at GSO), a
tropopause-based disturbance will move from cntl SC esewd and
offshore through 12Z. Meanwhile, an MCV evident in KRAX data over
wrn Chatham Co. will drift slowly, generally ewd and across the ne
NC Piedmont this morning/through ~16Z and across the Coastal Plain
this afternoon/through ~20-21Z.

At the surface, high pressure centered near Bermuda will continue to
extend wwd and across the South Atlantic states. Meanwhile, a lee
trough will sharpen with diurnal heating over the Foothills and wrn
Piedmont of the srn Middle Atlantic and Carolinas, while a sea
breeze will move inland and into the NC Coastal Plain and ern
Sandhills. A weak backdoor cold front will drift south and across
the Delmarva and Chesapeake Bay tonight.

While cloud tops have generally been warming with the area of
convection now moving across west-cntl NC, bursts of cooling and
deepening convection have been noted immediately surrounding the
center of the aforementioned MCV, as it moves east through a weakly
unstable environment over cntl NC. This compact area of convection
will probably be maintained as the MCV continues to move slowly ewd
through the day, and the airmass diurnally warms into the lwr-mid
80s and becomes moderately unstable throughout cntl NC. In the wake
of the MCV, additional, isolated/widely scattered showers/storms are
expected to develop along the lee trough and spread east and across
the wrn Piedmont later this afternoon-evening. A lack discernible
forcing features for tonight suggest today`s convection should
dissipate with nocturnal cooling, with seasonably muggy low
temperatures in the mid/upr 60s.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 230 PM Monday...

Tuesday should be a relatively average June day with a Bermuda high
in place and southerly return flow beneath weak ridging aloft.  A
weak backdoor cold front is forecast to settle down the Mid-Atlantic
coast but models have trended further north with its final push and
it doesnt quite reach Halifax and Edgecombe Counties, perhaps
stopping over southeast VA per NAM 925mb fields.  Aloft, there is a
weak circulation over TN today but it should drift more
northeastward tonight and doesnt appear to have much impact on
convective development tomorrow.  CAMs tend to slightly favor the
northeast CWA, again perhaps in closer proximity to the weak
convergence associated with the weak backdoor boundary.  PW will
increase to around 1.6, which is around the daily 90th percentile,
and thus will support a little better coverage or storms, which will
be slow moving given very weak tropospheric flow under the ridge.
Will trend 30-50 POPs toward the northeast CWA during the afternoon,
with otherwise partly to mostly cloudy skies once possible morning
stratus in the Piedmont burns off.  Highs will be in the mid to
upper 60s, falling only into the mid and upper 60s overnight with a
continued slight chance of a shower.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 250 PM Monday...

Shower/storm chances will peak mid week within warm and humid
conditions. We will then trend to dry weather and lower humidity by
Fri with the pattern shift to anomalously low heights over the Great
Lakes region and Ontario/Quebec, lasting through the weekend, albeit
with gradual air mass modification back toward normal by Sun/Mon.

Wed-Thu: Still appears that pops should be highest areawide Wed and
in the Coastal Plain on Thu. Northern stream troughing in the Upper
Midwest early Wed will continue to deepen and dig strongly to the SE
through the Great Lakes region through Thu, leading to gradually
strengthening WNW steering flow at our latitude and, especially, to
our W and NW, as a synoptic cold front slowly approaches from the
WNW. PW is expected to climb early Wed, nearing 2", near or
exceeding daily records, and we`ll have strengthening SW low level
jetting drawing greater moisture in from the Gulf. Models depict one
particular shortwave (perhaps an MCV from Mid Miss Valley
convection) swinging through the central and S Appalachians Wed
night into Thu morning, and with the in situ water content and low
level mass convergence amid improving mid level flow, it won`t take
much to kick off clusters of showers and storms. Will have pops
peaking at likely to categorical Wed into Wed night, then good
chance W to likely E Thu as 850 mb troughing pushes through the area
preceded by the low level jet shifting to the coastal Carolinas. A
few storms may be strong esp in the E Thu into Thu evening where
moderate to high MUCAPE is possible in tandem with the strengthening
mid level flow to 30-40 kts. Temps should be near to a category
above normal, with warm lows and clouds muting daytime heating a
bit.

Fri-Mon: The overall longwave pattern will shift to anomalously low
heights aloft across a large swath of the Great Lakes, adjacent
Canada and the Northeast as a deep northern stream low settles over
or just N of the Great Lakes. Deterministic models and ensemble
modeling systems are all in pretty good agreement on the overall
pattern, although differences persist regarding the amplitude,
wavelength, and orientation of the longwave trough axis, and these
differences show up well in the various model clusters. Generally,
though, with the cold front pushing to our SE, and a cooler air mass
moving in with lower dewpoints, confidence is high that we`ll have
generally dry weather starting Fri and going through the weekend,
although by Sun/Mon, minor perturbations within the fast NW steering
flow may knock down mid level heights briefly, resulting in bouts of
buoyancy along with passing DPVA, supporting a few diurnal showers
or storms, and will carry below-climo isolated afternoon pops both
days. Expect temps slightly below normal Sat, rebounding to near
normal Sun/Mon. -GIH
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&&

.AVIATION /18Z MONDAY THROUGH Saturday/...
As of 200 PM Monday...

A few isolated showers developing across the region this afternoon
is expected to continue through the early evening before diminishing
later tonight. Scattered to Broken clouds at around 2k-3k feet has
been observed over the Triad for a good part of the day as the lee
trough moves east into the Piedmont. Cloud bases of 3k- 4k ft can be
seen around the Triangle south and east. VFR conditions currently at
most TAF sites are not expected to last as coverage this afternoon
is expected to increase and MVFR conditions are expected to move
into the region this afternoon and evening, some ceiling and visby
restriction conditions are possible with a direct hit at a terminal
, but generally expect MVFR overnight with IFR low stratus
developing early morning especially over the northern terminals.
While the chance for storms across the region remains at around 25-
35%, precip chances will decrease overnight most of Tuesday morning.
Winds will generally be SW 5-10kts this afternoon decreasing to less
than 5 kts overnight. Expect another chance of showers/storms
Tuesday afternoon with day time heating kicking off again.

Outlook: Intermittent Sub-VFR conditions possible as isolated
afternoon and evening showers and thunderstorms anticipated again
Tuesday with more widespread coverage Wednesday as a front moves
through the area. Drier air is expected to move into the region
Friday through the weekend.

&&

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

&&

$$
SYNOPSIS...Hartfield
NEAR TERM...CA/MWS
SHORT TERM...BLS
LONG TERM...Hartfield
AVIATION...CA