905
FXUS62 KRAH 060546
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
145 PM EDT Thu Jun 6 2024

.SYNOPSIS...
A pre-frontal trough and cold front will move across the area
Thursday evening through early Friday. High pressure will move in
with cooler and drier air for the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 914 PM Wednesday...

Through the rest of this evening until midnight, the isold showers
currently moving across the southern I-95 corridor will continue to
move east; and meanwhile, additional isold light showers across the
NW Piedmont may move across the Triad, with very light if any
measurable rainfall.   With loss of daytime heating and very weak
forcing aloft, the showers moving into our Triad should diminish as
they move east.   Then after midnight, look for mainly dry
conditions for the rest of the night...thus have adjusted PoPs
accordingly.  With a recent grid update, we lowered tonight temps
across our SW Piedmont zones where heavier rain earlier this evening
has resulted in temps in the mid to upper 60s. Otherwise, lows
tonight across the rest of central NC should bottom out in the upper
60s to lower 70s under mostly cloudy skies.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 230 PM Wednesday...

...There is a Level-1/Marginal Risk For Severe Storms mainly along
and north of HWY 64...

Central NC will lie along the southern fringes of a mature mid-
latitude cyclone that will traverse along southern Ontario and the
Upper Great Lakes. Meanwhile, the associated belt of enhanced
westerlies will dip down into the Ohio Valley and northern mid-
Atlantic states with the trailing surface front crossing the area
Thursday night.

The day should start start out mostly dry with a near repeat
performance of gradual lifting of the overnight/morning stratus
layer through the late morning/midday.

Thereafter, a loosely organized line of showers and storms, likely
focused along the H8 trough/front, will move east off the mtns and
foothills and into the western Piedmont between 18-21z. The
convection is expected to move east through the remainder of the
afternoon and evening hours, before exiting the eastern/coastal
plain counties ~03z. It is unclear how the line will evolve as it
moves eastward. However, there is a increasing signal in the latest
hi-res model guidance that the line could weaken significantly after
sunset, especially across the southern and southeastern portions of
the forecast area.

Deep layer shear over NC has also trended weaker in recent runs,
with some of the guidance indicating a slight increase to 25-30 kts,
in a narrow belt extending along the NC-VA late towards sunset. If
there is chance for any isolated strong to severe storm, it will
likely be across the northern tier counties between 4-8 pm. Damaging
wind gusts are the primary threat.

Highs will be warmer than today, especially across the eastern half
of the forecast area where the later arrival of showers and storms
should allow for some strong heating. Highs ranging from mid 80s NW
to lower 90s SE.

Some isolated showers will be possible overnight/predawn hours
Friday morning as the lagging cold front crosses the area. Lows 65-
70.
&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 200 PM Wednesday...

Friday and Saturday: Aloft, an upper low will meander slowly
eastward through southern Ontario/southern Quebec, Canada Fri and
Sat. The attendant trough will progress eastward through the East
Coast states Fri as a s/w passes over central NC within the trough.
The trough will continue offshore Fri night. Nearly zonal flow
should prevail Sat/Sat night, with a weak s/w or two passing
overhead. At the surface, the cold front should be through central
NC Fri morning and continue eastward offshore through the aft/eve.
Cool high pressure centered just west of the southern Appalachians
will ridge eastward into the area Fri night. A trough may develop
over the area Sat and amplify Sat night, while the high weakens. For
now the forecast remains dry. Highs Fri ranging from low/mid 80s NW
to mid/upper 80s SE, with lows ranging from mid 50s north to mid 60s
south. Temps should be similar Sat/Sat night, highs a degree or two
lower and lows a couple/few degrees higher in some spots.

Sunday onward: There is still some uncertainty in this part of the
forecast, so confidence is on the low side. Aloft, as the parent low
swings through Quebec, Canada and the Northeast US a potent s/w will
drop south out of central Canada, through the northern Plains/upper
MS Valley Sat night/Sun, then continue around the parent low through
the Great Lakes/OH Valley Sun, amplifying the attendant trough in
the process. As the low lifts northward Sun night/Mon, the trough
should swing eastward into (GFS)/toward (ECMWF) the mid-Atlantic.
The s/w should move through central NC Mon night or Tue/Tue night.
At the surface, with the trough over central NC, a warm front may
briefly lift through the area Sun aft/eve, before another cold front
pushes through the area Sun eve/night. The front should stay east of
the area, with high pressure over the Plains/MS Valley through Mon
night. Beyond that, the medium-range guidance varies greatly, with
the ECMWF showing a low tracking along the Southeast US/Carolina
coast Mon night and Tue, while the GFS slowly develops a westward
retreating, inverted coastal trough Tue/Wed. The best chances for
showers/storms will largely be tied to the initial s/w sometime
between Sun eve and Mon night. Additional showers/storms will be
possible through mid-week, but confidence is low at this time.
Temperatures should be within a category or two of normal.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
As of 145 AM Thursday...

24-hour TAF period: Scattered patches of mid and high cloudiness
will stream across central NC, before IFR/MVFR stratus and
stratocumulus again develop late tonight by around 08-10z. The
highest confidence of this occurring is at the Triad terminals (INT
and GSO), followed by RDU and FAY, and lastly RWI. S/SW winds should
stay elevated overnight (around 5-10 kts) and this combined with the
low stratus fog is not expected to be a concern. Conditions
will improve to VFR by mid to late morning, but a line of showers
and thunder storms associated with a pre-frontal trough is
expected to move east through central NC during the afternoon and
evening. The best guess is for the line to reach the Triad terminals
by mid afternoon, followed by RDU near the end of the TAF period,
though timing is still a bit uncertain. MVFR or even IFR ceilings
and visibilities will be possible as the line moves through, along
with gusty winds.

Outlook: The line of showers and storms will continue to impact
southern and eastern parts of the area through the evening, with
sub-VFR conditions still possible. VFR conditions and dry weather
are expected to return Friday through the weekend.

&&

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

&&

$$
SYNOPSIS...Badgett
NEAR TERM...np
SHORT TERM...CBL
LONG TERM...KC
AVIATION...Badgett/Danco