594
FXUS62 KRAH 131931
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
330 PM EDT Tue May 13 2025

.SYNOPSIS...
A slow moving upper low centered over the Tennessee Valley will
slowly lift northeast into the Ohio Valley and Mid-Atlantic states
through Wednesday, bringing wet and unsettled weather to the region.
The low will weaken and move NE of the area by late week with hot
and humid weather to follow.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 320 PM Tuesday...

* Flooding Threat Lingers through the early evening

* Marginal/Level 1 Risk of of Severe Storms through the early evening

Convection thus far has largely been confined to the southern and
western Piedmont where clearing has been most abundant. Elsewhere,
remnant stratus has largely limited convective initiation. The
lingering stratus has almost exited the northern Coastal Plain which
should help to destabilize areas east of US-1 the next few hours.

Any severe weather should be highly isolated, with damaging wind
gusts and hail the biggest threat. If any showers and storms develop
in the Coastal Plain, there is still a low-end chance for a brief
spin up tornado. The SRH field should be weaker compared to
yesterday/last night, but there is still enough of a signal to
warrant monitoring for brief spin-ups this evening out that way (SPC
still has a 2% contour for tornado risk for areas generally
northeast of Raleigh).

The Flood Watch remains in effect for those along and east of US-1
through 06Z tonight. Any flash flooding will be highly localized to
urban areas (highest chances in the Durham/Chapel Hill vicinity).
Otherwise expect showers and storms to diminish overnight.

Lows in the upper 50s to lower 60s are expected with patchy fog
possible near sunrise tomorrow morning.

 &&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 320 PM Tuesday...

The mid/upper level low initially over the TN Valley will eject ene
over the southern Appalachians, NC/VA Foothills, and northern
Piedmont through Wednesday evening.  An associated strong vorticity
maxima, coupled with a lingering moisture rich environment (PWAT
still ~150 % of normal) should generate numerous diurnal showers and
storms across our area.

As the low ejects ene, considerable cooling aloft is expected. Cloud
cover will erode through mid to late morning, and with increasing
sfc heating, expect instability to rise by early Wednesday
afternoon.  Mid-level flow will be somewhat limited (~20 to 30
kts), but given the cooling aloft and low freezing levels, small
hail appears possible in any stronger storm.  Isolated stronger
storms may be able to tap into pockets of stronger shear, and as
such can`t rule out sporadic larger hail or isolated damaging wind
gusts.   Overall though, the environment appears marginal.

While flooding should be as big of a concern as the prior two days,
given the saturated soils and rich moisture environment, can`t rule
out instances of isolated flash flooding in urban areas. Overall
though, the flooding threat should be minimal.

Convection will wind down with loss of heating, with a generally
drier night expected.

Highs will reach the upper 70s to lower 80s. Warm overnight lows in
the lower 60s are expected again.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 330 PM Tuesday...

Shortwave ridging will build over the TN Valley on Thursday and into
the southern Appalachians on Thursday night, with associated height
rises. Model soundings indicate this will bring a decent capping
inversion that should limit convective development, but isolated
showers/storms will still be possible as good surface heating and
dew points in the mid-to-upper-60s result in moderate
destabilization. This is especially true in the east, in closest
proximity to the departing shortwave that will be moving into the
Delmarva/NJ and into the Atlantic. So have low chance POPs there,
decreasing farther west. High temperatures will turn above average,
in the mid-80s to 90. Lows Thursday night will only drop into the
mid-to-upper-60s.

Convective coverage may end up being isolated at best on Friday
also, as models have been trending to a slower exit of the shortwave
ridging which still looks to extend NE into the Carolinas in the
afternoon. However, by Friday night we will finally begin
experiencing some weak mid-level height falls from the next deep
closed low that moves east across MN, WI and Lake Superior, which
will help suppress the ridging. A surface trough will also be in
place across the southern Mid-Atlantic. But by this point, we will
lose daytime heating and instability. So just have slight chance
POPs across the north and west on Friday/Friday night. Hot
temperatures will the bigger concern with the ridging aloft and SW
low-level flow. Forecast highs are in the upper-80s to lower-90s
(maybe isolated mid-90s in the typical hot spots). Dew points will
increase to the upper-60s and lower-70s, so heat indices are
forecast to reach the mid-90s to 100 from the Triangle to the south
and east. Temperatures will stay mild on Friday night, with lows in
the upper-60s to lower-70s.

As the mid/upper low and occluded surface low track east across
southern Ontario and the northern Great Lakes on Saturday, a cold
front looks to move through central NC on Saturday night. While
shear and instability look decent, moisture/precipitation with the
front is not too impressive on guidance, as we only get a glancing
blow in upper forcing with the low tracking so far to our north.
Ensemble mean QPF is only around a tenth of an inch or less. So only
have slight to low chance POPs in the afternoon and evening, but
still can`t rule out a few strong to severe storms. Saturday`s
temperatures may be kept down a bit by the increased precipitation
chances, but overall they should still be quite warm with highs in
the upper-80s to lower-90s, and heat indices in the upper-90s in the
SE.

The mid-level flow will turn northwesterly from Sunday into Tuesday,
as we are caught between the low over New England/SE Canada and
strengthening ridging to our west. At the surface, the cold front
looks to get hung up to our south, keeping us relatively stable. So
only have slight chance POPs in the south Sunday and Monday, then
areawide on Tuesday as the next cyclone tracks over the northern
Plains and upper Midwest and the front possibly gets pushed north
into our region as a warm front. Thicknesses only slightly fall
behind the cold front, so still forecast above-normal highs in the
80s from Sunday through Tuesday, with lows in the lower-to-mid-60s.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 150 PM Tuesday...

Lingering MVFR/IFR ceilings (KINT/KRWI) will lift to VFR in the next
few hours. Otherwise, showers and storms have developed across the
western Piedmont this afternoon. Expect this activity to move east
and blossom across all of central NC this afternoon and evening.
Brief sub-VFR conditions may be possible from any terminal-impacting
storms during this period.

Showers and storms will diminish overnight, but partial clearing
overnight may lead to fog development, potentially dense between 06-
12z, mainly across the northern terminals.

Outlook: Chances for diurnal scattered showers and storms will
continue through the period.  Morning fog and low stratus will be
possible each morning, especially in areas that received significant
rainfall the previous day.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for NCZ007>011-024>028-041>043-078-
089.

&&

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