Durham, North Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

174
FXUS62 KRAH 290828
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
428 AM EDT Thu May 29 2025

.SYNOPSIS...
A mid and upper-level disturbance will move northeast across the
Carolinas this afternoon and evening. Low pressure will strengthen
across the lower Ohio Valley later tonight and across and offshore
the Middle Atlantic Friday and Friday night. A trailing, strong cold
front will move across the southern Middle Atlantic and Carolinas
Friday afternoon and evening.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 425 AM Thursday...

Split flow will continue east of the Rockies, downstream of a rex
blocking pattern from the Canadian Prairies to just offshore Baja
CA. Within the nrn branch flow, a shortwave perturbation centered
over the e-cntl NE/SD border this morning will amplify considerably
while digging across the mid MS Valley through 12Z Fri, then even
more considerably across the OH Valley and Middle Atlantic on Fri.
Meanwhile, a relatively high amplitude, srn stream trough, evident
in water vapor satellite data over the ArkLATex and earlier in 00Z
upr air data over TX, will pivot newd across the Southeast and srn
Middle Atlantic through 12Z Fri. It will be slightly preceded by a
convectively-amplified mid-level trough and 30-40 kt mid-level jet,
and an accompanying area of rain and storms centered over the cntl
Gulf Coast states this morning, which will follow a similar but
slightly earlier path across the Carolinas this afternoon-evening.
Mid-level height falls and forcing for ascent will maximize between
30-50 meters over cntl NC this evening with the approach of the srn
stream troughs, then continue overnight owing to the approach of the
deepening/amplifying nrn stream trough.

At the surface, low pressure that tracked through the srn Middle
Atlantic Coastal Plain on Wed was centered at ~1015 mb just off the
srn NJ coast at 08Z. This low will continue newd along and just
offshore the nrn Middle Atlantic and srn New England coast today,
while following weak high pressure drifts across cntl and ern NC/VA.
A front trailing the low extended sswd along and just offshore the
NC coast, then wnwwd across SC this morning. This boundary will
retreat nwd across cntl NC as a warm front, with diurnal heating and
south to north erosion of morning low cloudiness, today. The models
also indicate an extensive outflow boundary related upstream
convection over the cntl Gulf Coast and Southeast may develop and
strengthen and move across the Carolinas this afternoon and evening.

Multi-layered overcast, dominated by low clouds this morning and a
canopy of mid and high ones that will continue to thicken and lower
with the approach of the srn stream troughs throughout the day-early
night, will limit sunshine (to filtered at best) for another day.
Temperatures should nonetheless warm relative to previous days`
unseasonably cool CAD ones, and into the mid-upr 70s across the nrn
Piedmont and nrn Coastal Plain to lwr-mid 80s elsewhere. That
diurnal warming of seasonably moist low-levels, characterized by
surface dewpoints in the mid/upr 60s, will result in a weakly
inhibited and weakly to moderately unstable airmass over cntl NC.
While isolated to scattered convection may result by midday over the
srn and wrn Piedmont, where confluence will be maximized on the wrn
periphery of the weak high drifting across cntl and ern NC/VA, then
along the retreating warm front through early afternoon, the better
chances for convection and surrounding stratiform rain will
accompany the srn stream troughs across cntl NC later this afternoon-
evening. A few storms, probably multi-cell ones given modest swly
mid-level flow and organization along aggregate outflow from
upstream convection, may produce strong to locally damaging wind
gusts.

Convection should gradually diminish in intensity while moving
across cntl and ern NC this evening, given both nocturnal and
diabatic/outflow cooling, though surrounding and remnant
stratiform rain may linger for much of the night especially over
the ern half of cntl NC. With some potential for at least partial
clearing over the srn and wrn Piedmont late, in the wake of the
rain, patchy fog and/or low overcast may develop there, with low
temperatures throughout cntl NC in the mid/upr 60s.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 245 AM Thursday...

Low pressure will be over eastern Kentucky Friday morning with a
cold front extending southwest to Texas. Although an isolated shower
is possible in the morning, it appears that the morning should
generally be dry before the front approaches from the west. Models
are in fairly good agreement with the timing of precipitation, bring
showers and storms into the Triad during the early to mid afternoon,
mid to late afternoon across the Triangle and Fayetteville, and late
afternoon along the I-95 corridor. The HREF depicts a secondary
round of precipitation a few hours after the primary cold front, but
looking at individual members, it appears that the last two runs of
the NAM Nest have been slow outliers, and those solutions were not
used. The entire forecast area remains under a slight (level 2 of 5)
risk for severe weather from the Storm Prediction Center. Damaging
winds and large hail remain the primary hazards, with an isolated
tornado a secondary threat. The SPC discussion states that
supercells and bowling line segments will be favorable considering
the instability and shear values. Highs will be in the upper 70s and
lower 80s.

The cold front will be east of the forecast area by sunset. While
models are in good agreement that showers/storms will continue along
the I-95 corridor after sunset, the models are also in good
agreement that conditions should be dry locally by 06Z, so have
tried to include that trend with decreasing pops during the evening
into the overnight. Skies should also clear quickly overnight, and
lows will drop into the mid to upper 50s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 245 AM Thursday...

Models have become a bit more divergent with how much shower
coverage is expected on Saturday. The 28/12Z and 29/00Z ECMWF runs
show much greater coverage across the south than they previously
have, while the 28/18Z EPS barely shows any coverage. The 29/00Z GFS
barely glances the northern CWA, while the 29/00Z GEFS looks pretty
consistent to the inherited forecast, clipping northern counties
with chance pops and slight chance pops except in southern counties.
Considering the varying solutions, have not made much change to this
part of the forecast, keeping slight chance pops across much of the
area and chance pops north and east of Raleigh. Ensembles continue
to show a slight chance of showers Sunday across western counties
with a weak front, which has been a consistent trend despite
deterministic models remaining dry. The ensembles previously showed
dry weather Sunday night with the frontal passage, but are now
maintaining some minimal pops overnight, and have maintained this
with the new forecast. The front could linger along the North
Carolina coastline Monday, keeping an isolated thunderstorm east of
I-95. After that, high pressure takes over the southeastern United
States for the rest of the forecast period. Highs will rise a couple
degrees each day through the period - with values Saturday ranging
from the mid 70s to the low 80s and on Wednesday ranging from the
low 80s to the low 90s. Lows will generally be in the 50s Saturday
and Sunday night, then in the 60s Monday and Tuesday night.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
As of 230 AM Thursday...

A mix of MVFR and low VFR ceilings, beneath a canopy of high-level
ones, will likely limit fog development in an otherwise favorable
environment over cntl NC this morning. Instead, the MVFR ceilings
will likely expand in coverage and lower through 12Z, especially
over the Piedmont. MVFR ceilings will then be possible throughout
cntl NC, as daytime heating acts upon moist low-levels and
concentrates that moisture (and probable cloud bases) at the top of
a developing and deepening mixed/boundary layer, and beneath a
residual temperature inversion related to recent days` cold air
damming. Any such MVFR ceilings should then lift and/or scatter to
VFR between 17-20Z.

A mid and upr-level disturbance, and an accompanying area of rain
and storms centered over the cntl Gulf Coast states this morning,
will move newd and across the Carolinas this afternoon and evening,
Given uncertainty in coverage and impacts downstream in cntl NC,
PROB30 groups were used to highlight associated operationally
significant weather at this time range. Some lingering stratiform
rain, and also flight restrictions in stratus and/or fog, may result
overnight-Fri morning.

Outlook: Strong to severe thunderstorms will be possible along and
ahead of a cold front on Fri, and a few showers/storms may redevelop
with daytime heating mainly at RWI on Sat. Additionally, gusty
surface winds are expected from the southwest Fri and west northwest
Sat.

&&

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

&&

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