941
FXUS62 KRAH 282000
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
400 PM EDT Tue May 28 2024

.SYNOPSIS...
A series of moisture-starved, reinforcing cold fronts will lead high
pressure from central Canada and the Great Lakes to the Middle
Atlantic and Carolinas this week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 345 PM Tuesday...

A synoptic trough stretching through a couple of shortwave
perturbations over s-cntl ON and wrn PA/ern OH will continue to lift
newd and across the Northeast and middle Atlantic, with associated
glancing, ~20-30 meter/12 hr height falls across the srn Middle
Atlantic (VA/NC) through this evening.

At the surface, a front has moved/mixed ewd and become stationary
over ern NC, near and just inland of see breeze and outflow along
the coastal areas. Seasonably dry, wly flow has become established
over cntl NC, between the front and weak high pressure building
across the mid-South and TN Valley.

Cntl NC will generally remain between isolated to widely scattered
convection in a moderate instability axis along the front/sea
breeze/outflow over ern NC, and other, diurnally-driven convection
accompanying the aforementioned synoptic trough aloft over the
Middle Atlantic/cntl Appalachians/lwr Great Lakes. Mainly diurnal
cumulus over cntl NC will dissipate and yield to a mainly clear
night, with low temperatures in the mid 50s to mid 60s.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 355 PM Tuesday...

A shortwave trough now over WI/IA will dig sewd into the OH Valley
tonight and then pivot across and offshore the Middle Atlantic Wed-
Wed night.

At the surface, an Appalachian-lee trough will develop with diurnal
heating Wed and be overtaken by a moisture-starved, reinforcing cold
front that will settle south across the Carolinas Wed night.

Like that which is occurring with the shortwave trough pivoting
across the Middle Atlantic today, diurnally-driven convection will
likely redevelop and accompany the aforementioned shortwave trough
that will pivot across the region Wed, with the greatest coverage
from the NC/VA border nwd. While the forecast will remain a dry one
for now, a slight/small chance of an afternoon shower/storm may be
needed over at least the nrn NC Piedmont. It will otherwise remain
less humid than recent days, and slightly cooler, with highs in the
low-mid 80s and lows mostly in the 50s to around 60.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 232 PM Tuesday...

A short wave trough pivoting across the eastern Great Lakes on
Thursday will move off the Northeast and Mid-Atlantic coastal
regions by early Friday and will be followed by sfc high pressure
building into much of the Eastern US during the rest of Friday and
into early Saturday.  This high will bring with it a relatively
cooler airmass into our region, which will result in high temps Thu-
Sat in the upper 70s to lower 80s, which is several deg below
normal.  The main forecast challenge is whether or not the
aforementioned s/w trough will have enough moisture or to work with
across our area to result in any shower activity with it`s passage.
The majority of the guidance suggests areas well north and east of
Raleigh will have the best chance to see a passing shower late on
Thursday or Thursday night, and the NBM keeps PoPs aob 14% across
our entire CWA.  For now will go with NBM keeping our forecast dry
during that time (PoPs below 15%), but if PoPs continue to trend
higher, they may be needed across our northeast and far eastern
zones.

Once the high moves offshore by mid-Sunday, look for a warming and
moistening trend with temps near normal for the rest of the period.
Both the GFS and ECMWF suggest a series of low-amplitude s/w troughs
will transit the westerly upper flow and may provide enough forcing
for some isold mainly diurnal shower/tstm activity late in the days
Sunday through Tuesday, but certainly not a washout during that time
with overall low QPF.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 155 PM Tuesday...

Although a weak shower cannot be ruled out through this evening, as
a mid/upr-level trough pivots across the Middle Atlantic, the
likelihood of any impacting any one location in cntl NC --should one
occur at all-- is less than 10 percent. The passage of another
disturbance in cyclonic flow aloft will result in a slightly higher,
~10-15 percent chance of a shower over the nrn half of cntl NC Wed
afternoon. Dry, wly flow will otherwise favor VFR conditions in cntl
NC through Wed.

Outlook: Canadian high pressure will build from cntl Canada to
the middle Atlantic and favor VFR conditions in cntl NC through Sat.
As the high shifts offshore, sly flow and increasing moisture will
increase the risk of patchy fog and stratus Sun morning and a chance
of showers/storms Sun afternoon-night.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...np
AVIATION...MWS