-- Discussion containing changed information from previous version are highlighted. --
909
FXUS62 KRAH 271759
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
158 PM EDT Fri Jun 27 2025

.SYNOPSIS...
A backdoor front will become quasi-stationary over southern VA and
far northeastern NC today, then return north as a warm front across
the Middle Atlantic coast on Saturday. A mid and upper-level ridge
will otherwise weaken while drifting from the southern Middle
Atlantic to near and east of Bermuda this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1125 AM Friday...

A strong backdoor cold front and differential heating zone evident
in satellite and surface observational data over far srn VA this
morning, with a pronounced frontal inversion evident immediately
behind it in the 12Z WAL and IAD RAOBs, may make a little additional
swd progress into far nern NC today, before becoming quasi-
stationary there through tonight. A broad pre-frontla trough, and
weak low centered over the nrn Coastal Plain of NC this morning,
will otherwise remain in place.

While a slight chance of convection will exist within the broad, pre-
frontal convergence axis throughout cntl NC, where strong diurnal
heating will yield persistence lwr-mid 90s and a moderately unstable
and weakly inhibited airmass, the relative greatest chance and
coverage of storms may result within the moisture convergence max
along and immediately ahead of the front and low over the nrn-cntl
Coastal Plain and ne Piedmont. Continued very weak wind profiles
below a lingering 50 kt ely jet at the tropopause will favor slow
and erratic cell motions, with cloud layer mean wind of only 5 or so
kts from the south. A combination of that weak flow and PWs forecast
to increase to around 1.75" will favor brief downpours and strong to
tree-damaging downburst winds from pulse cells.


.PREV DISCUSSION... /ISSUED 240 AM EDT Fri Jun 27 2025/

* There is a Marginal Risk (level 1 of 5) for severe thunderstorms
  across much of central NC this afternoon and evening.

Aloft, high pressure will continue ridging wwd across the mid-
Atlantic, while the weak area of low pressure drifts nwwd to over
the Southeast US today, lingering there through tonight. Weak
perturbations around the mid-level low crossing the area this
aft/eve could help kick off showers and storms, especially along
residual surface boundaries and convergence zones. The RAP shows
SBCAPE values ranging from around 1500 J/Kg in the west to around
3000 J/Kg in the east this evening, while the NAM generally peaks in
the 2000 to 3000 J/Kg range area-wide. PWATs of 1.7 to 1.8 inches
are also expected. Wind profiles remain relatively weak, with bulk
shear values still less than 20 kts. However, 0-3 km lapse rates are
still forecast to be strong, so isolated damaging wind gusts are
possible. The storms will likely again be pulse in nature and
isolated to widely scattered in coverage. Any convection that
develops should taper off with loss of heating this eve.

As for temperatures, max low-level thicknesses continue to decrease,
peaking around 1430-1435 meters this evening. Highs today still 5-10
degrees above normal, in the low to mid 90s expected, with heat
index values of up to 102 degrees. Lows tonight should be in the low
to mid 70s.

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 250 AM Friday...

* Status quo, with storm chances peaking mid afternoon through the
  evening, highest over the Piedmont and W Sandhills.

* Continued hot and humid.

More of the same is expected Sat/Sat night, with very little change
in the overall regime featuring above normal PW and very light flow
through the column. Recent RAP runs show moderate to high SBCAPE in
the afternoon through evening, albeit with poor deep layer bulk
shear. The weak upper low is expected to be over GA, with the
offshore-centered ridge extending into E NC, and the resulting SSE
mid level flow should draw weak vorticity into our SW sections and
into W NC through the afternoon/evening, although the weak flow will
lead to just modest DPVA. With the weak surface trough holding in
place down through the W Piedmont, subtle low level mass convergence
in conjunction with residual outflows and other discontinuities
should serve as foci for storm initiation by early to mid afternoon.
Storms are expected to be discrete or clusters, slow-moving with
mergers, which increases the chance for localized heavy downpours
and raises the risk for isolated flooding given PWs in the 90th
percentile. And the high CAPE and potential high DCAPE will bring a
threat for isolated damaging downburst wind gusts, especially in the
west half where storm coverage will be highest. The RAP and HREF
probabilities continue to focus the greater coverage of convection
over our W, and will carry 35-50% pops there, with slightly lower
pops in the E. Storms should slowly dwindle in coverage and
intensity from late evening into the early overnight hours as CAPE
lowers and CINH takes over. Highs will still be warm, upper 80s to
mid 90s, with lows 70-76. -GIH

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --
As of 300 PM Friday...

* Typical summer pattern across NC much of this week with above
  normal temperatures and daily shower/thunderstorm chances

* Increased shower/storm chances Tuesday/Wednesday, turning drier
  Thursday/Friday

The forecast will feature a fairly typical summertime pattern
through early next week with Bermuda high pressure in place at the
surface and aloft. Daily shower and thunderstorm chances are
expected through Monday, with the highest chances generally favored
in the western Piedmont. Afternoon highs will top out in the low to
mid 90s with lows generally in the lows 70s (west) to the mid/upper
70s (southern Coastal Plain). Heat indices will once again range
from the upper 90s to lower 100s. Certainly not cool, but not as
high as what was seen earlier this week.

Looking ahead to Tuesday, a longwave trough will migrate out of the
northern Plains, sharpening as it approaches the western slopes of
the Appalachians. Modest moisture advection ahead of the trough and
the attendant surface front should promote the development of more
widespread shower and thunderstorm activity across the area Tuesday
afternoon and evening. PW`s will top out around 2" ahead of the
front and with MLCAPEs running anywhere from 1000-1500 J/KG, areal
coverage of storms should be noticeably higher than previous days.
With synoptically driven support in the form of the trough, some
some storms could be strong to severe. There is still some inherent
uncertainty at this lead time with respect to how far south this
front will make it before washing out/dissipating but the threat for
more widespread precip chances is certainly agreed upon by the
models. PoPs will range anywhere from 60-80 percent Tuesday
afternoon/evening, with the highest values in the west. The front
should slowly sag through the area Wednesday, eventually
stalling/washing out across the Sandhills/southern Coastal Plain on
Thursday. In the wake of the trough, mid level subsidence and drying
should yield lesser precip chances Thursday and Friday.

Temps Tuesday through Thursday will once again range from the low to
mid 90s, with overnight lows in the low to mid 70s. The exception
will be Wednesday when highs may only reach the upper 80s with the
front overhead and associated increased cloud cover.
-- End Changed Discussion --

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 155 PM Friday...

Showers and storms with heavy rain and gusty downburst winds will
continue to concentrate through this evening in proximity to a
backdoor front over far nern NC and srn VA, and a nearly stationary
pre-frontal low centered near KASJ, with the relative greatest
probability of occurrence in cntl NC at RWI and RDU. There is also a
chance that rain-cooled air/outflow from storms developing over the
Blue Ridge will merge and spread sewd across the Foothills and nw
Piedmont through this evening, with possible impacts at INT/GSO.
Additional, isolated cells may develop with the afternoon-early
evening heating at FAY.

The aforementioned backdoor front, and following post-frontal, low
overcast/ceilings, may sag swd into the far nrn NC Piedmont tonight.
Associated LIFR-IFR ceilings may result Sat morning at INT and GSO.
The typical visibility fluctuations in mist will also be possible at
RWI early Sat morning.

Outlook: After generally scattered, diurnally-driven convection
through the weekend, shower/storm chances will increase with the
approach of an upr-level trough and surface cold front next Tue-Wed.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...MWS/KC
SHORT TERM...Hartfield
LONG TERM...Leins
AVIATION...MWS