803
FXUS62 KRAH 180604
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
204 AM EDT Tue Aug 18 2026

.WHAT HAS CHANGED...

* No significant changes

&&

.KEY MESSAGES...
As of 250 PM Monday...

1) There is a threat for isolated to scattered strong to severe
storms this afternoon and evening, with a Slight (level 2 of 5) risk
in much of the Piedmont and a Marginal (level 1 of 5) risk
elsewhere. Damaging winds are the primary threat.

2) A Heat Advisory continues today from the Triangle region to the
south and east, and a second Heat Advisory has been issued for
nearly the same area on Tuesday.

3) Heat and humidity lingers much of the week, followed by increased
storm chances Thursday through Saturday.

&&

.DISCUSSION...
As of 250 PM Monday...

KEY MESSAGE 1... There is a threat for isolated to scattered strong
to severe storms this afternoon and evening, with a Slight (level 2
of 5) risk in much of the Piedmont and a Marginal (level 1 of 5)
risk elsewhere. Damaging winds are the primary threat.

As of 2:30pm, precipitation coverage is extremely isolated in North
Carolina, with one or two storms along the VA/NC border to the north
of the Triad. A cluster of showers and thunderstorms currently
across western Virginia is expected to expand in size and strength
as it moves to the southeast during the next several hours. Forsyth
and Guilford counties were just added to a severe thunderstorm watch
through 8pm. If any severe thunderstorms do occur in this area, it
will likely be towards the end of the watch period, and cannot rule
out the possibility that if severe thunderstorms remain ongoing
around 8pm, the watch may need to be expanded spatially and/or
temporally. As the watch was just issued, it will be several hours
until it is known whether the expansion will be needed or not.


KEY MESSAGE 2... A Heat Advisory continues today from the Triangle
region to the south and east, and a second Heat Advisory has been
issued for nearly the same area on Tuesday.

Nearly the entire forecast area has temperatures in the 90s as of
2:30pm, with isolated readings in the upper 80s or low 100s.
Locations currently under a heat advisory generally have heat index
values in the low to mid 100s, and these values will likely rise
over the next couple of hours. After coordinating with neighboring
offices, another heat advisory has been issued for Tuesday, valid
for the same area as today`s heat advisory other than excluding
Orange and Durham counties.


KEY MESSAGE 3... Heat and humidity lingers much of the week,
followed by increased storm chances Thursday through Saturday.

Heat and humidity will remain the main story from Tuesday through
Thursday, perhaps lingering into Friday. After today, storm chances
will decrease Tuesday and Wednesday with overall limited forcing.
This is not to say that storms will not occur, but that overall
coverage will be more isolated. The best chance of storms Tuesday
and Wednesday appears to be over the Coastal Plain in line with the
sea-breeze.

Towards the latter part of the week, ensemble guidance is indicating
an increase in deep-layer moisture and shear tied to overall
troughing set to build south and east. This pattern starts to emerge
as early as Thursday afternoon and evening, lingering perhaps into
Saturday. Guidance indicates a surface frontal system tied to the
upper-level feature, which should focus better chances for showers
and storms. Some AI guidance also hints at a return severe risk with
the shear and instability, though we are not presently highlighted
from SPC.

As for the heat and humidity, a continued stretch of heat indices
ranging from 103 to 108 will occur, primarily across the Triangle,
southern Piedmont, Sandhills, and central to southern Coastal Plain.
A heat advisory may be additionally needed Wednesday and Thursday.
The heat risk in these areas approaches a level 3, with at most a
level 4 out of 4 risk in isolated locations. These risk levels will
affect anyone without adequate cooling or hydration. Heat may linger
into Friday but increased storm chances then should limit overall
advisory criteria at this stage.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 200 AM Tuesday...

Isolated to widely scattered showers and storms are currently
tracking east over the far NE Piedmont and northern Coastal Plain. A
brief shower or storm can`t be completely ruled out at RDU and RWI
for another hour or two, but much of the convection is going to the
north of the terminals. Otherwise, can`t completely rule out some
very patchy mist/low stratus around INT and GSO after 08z where
about a half inch of rain fell yesterday. But the signal for this
doesn`t show up in most guidance, and confidence in any sub-VFR
restrictions remains quite low. Any mist/low stratus will quickly
dissipate after sunrise.

VFR will largely prevail during the day Tuesday. Isolated showers
and storms can`t be ruled out over the NE Piedmont and Coastal Plain
in the afternoon and evening, associated with lee troughing and the
sea breeze. This includes RDU and RWI. But coverage should be
limited, and confidence in any sub-VFR restrictions occurring at the
terminals is low. Winds will be largely from the NW and light
(around 7 kts or less).

Outlook: There will be a minimal chance of showers and thunderstorms
Wednesday, as precipitation should remain closer to the North
Carolina coast. An approaching front should bring a higher chance of
showers/storms Thursday, and the front should linger into the
weekend, bringing scattered showers/thunderstorms through the
period. Flight restrictions will be possible in any precipitation,
as well as making those locations more likely to have flight
restrictions around dawn the next morning.

&&

.CLIMATE...

Record High Temperatures:

August 18: KFAY: 98/1988
August 20: KFAY: 102/2007


Record High Minimum Temperatures:

August 18: KGSO: 75/2017 KRDU: 77/1995 KFAY: 78/2021
August 19: KRDU: 77/1988 KFAY: 76/1940
August 20: KRDU: 75/2007 KFAY: 78/2005
August 21: KRDU: 76/2009 KFAY: 77/2005
August 22: KFAY: 75/2018


&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 8 PM EDT Tuesday for NCZ026>028-
040>043-073>078-083>086-088-089.

&&

$$

DISCUSSION...Green/Kren
AVIATION...Danco/Green