820
FXUS62 KRAH 211203
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
803 AM EDT Fri Aug 21 2026

.WHAT HAS CHANGED...

*  Waves of showers and thunderstorms expected; however, models
   including the HRRR, NAMNEST, and others have done an extremely
   bad   job with this pattern in convective initiation and general
   location, timing, and amounts. Thus, we will not have high
   confidence in this forecast when it comes to specifics. Yet, it
   is a pattern that supports flash flooding potential.

*  A Flood Watch will be issued for portions of the southern and
   eastern Piedmont, Sandhills, and Coastal Plain given the
   potential for 3-6 hour very heavy rainfall rates late this
   morning through the evening.

 * The threat of severe thunderstorms along and south of the
   boundary has increased, especially SW of RDU this afternoon.

&&

.KEY MESSAGES...
As of 155 AM Friday...

1) A Flood Watch will be issued for a good portion of Central NC,
except for the Northwest Piedmont (Triad Area) east along the NC/VA
border.

2) There is a Slight Risk of severe thunderstorms today into this
evening, mainly over southern portions of central NC.

&&

.DISCUSSION...
As of 155 AM Friday...

KEY MESSAGE 1...  A Flood Watch will be issued for a good portion of
Central NC, except for the Northwest Piedmont (Triad Area) east
along the NC/VA border. Timing most likely will be 16z today through
12z/Saturday.

The main synoptic boundary was located over our region early today,
analyzed from near the Tidewater of VA southwest through the
northern Triangle Area and southwest to Charlotte. A couple of
clusters of showers and thunderstorms have been developing ENE along
the boundary from CLT to near RDU. GSP recently had Severe
Thunderstorm Warning around Charlotte. Another, much larger complex
of thunderstorms was located over NE Alabama into GA and
southwestern NC, moving NE. Current PWs were running between 1.8 and
2 inches along and south of the boundary, with a max of 2.2 over NE
AL. This complex should continue moving NE as the mid/upper trough
approaches the southern Appalachians this morning. PWs will increase
to 2 to 2.5 inches along and ahead of the feature (boundary).

We will place the Flash flood watch along and south of the expected
average placement of the boundary today. The latest CAMS suggest it
will drift southward through 12z, possibly sagging through the
Triangle. By 18z... it should be somewhere near a line extending
from near Rocky Mount southwest to around our south of Raleigh and
southwest to around Wadesboro. As the mid level trough approaches,
the boundary may waver back north 25 to 50 miles as a surface wave
approaches this afternoon. So, the Flood Watch would be favored
mainly south of I-85/I-40 east to near Wilson (southward). Several
waves of showers/thunderstorms are expected along and south of the
boundary, with showers north. The highest QPF should be found within
the Watch area, with 2-4+ inches likely - mostly in 3-6 hours. Some
local 5+ inch amounts will be possible.

Most guidance (which again has been unreliable thus far) suggests
convection will taper off this evening, with additional
showers/storms possible again later tonight (mainly south and east
portions of the current watch. We will see.

KEY MESSAGE 2... There is a Slight Risk of severe thunderstorms
today into this evening, mainly over southern portions of central NC.
This is surrounded by a marginal risk (near and south of the
boundary).

Morning cloudiness and convection should taper off along and south
of the aforementioned boundary. There should be a rapid development
of new showers/storms with the approach of the mid level support
late this morning or early afternoon. SPC has upgraded southern
portions of our region into the slight risk category as the
potential for wet microbursts has increased. Strong heating in the
warm sector will lead to very unstable conditions ahead of the wave
of low pressure and cold front. Storms will spread east through the
warm sector, with the threat of some 60 mph winds and associated
torrential rainfall this afternoon.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
As of 800 AM Friday...

24 hour TAF period: IFR/low MVFR stratus has finally reached the NE
Piedmont and northern Coastal Plain, including RDU and RWI. This
could be slow to lift and linger into late morning or early
afternoon, particularly at RWI where an LIFR ceiling can`t be ruled
out for a couple more hours. Patchy fog/mist may also result in
mainly MVFR visibilities for a couple more hours, mainly in the
south and east. Meanwhile around INT and GSO, a cluster of vigorous
showers and storms with very heavy rainfall and gusty winds is
approaching and will be there within the next hour, with a larger
line of convection behind that. Brief IFR/MVFR conditions will be
possible as the storms move through.

By early afternoon, numerous showers and storms will then rapidly
develop along and south of a boundary stretching across central NC,
before moving north into the rest of the area. Gusty winds and sub-
VFR restrictions will be possible with any storms. Otherwise winds
will be largely from the E/NE and light (around 7 kts or less).

The most widespread precipitation will come to an end by about 04-
06z Saturday, but some lingering showers are still possible
overnight. Otherwise, expect IFR/LIFR ceilings and MVFR/IFR
visibilities to quickly overspread the entire region during the
evening and overnight hours.

Outlook: Showers and storms with possible heavy rain and sub-VFR
conditions will primarily shift to FAY/RWI on Saturday. Drier
conditions with less flight restrictions are expected for Saturday
night through Tuesday.

&&

.CLIMATE...
Record High Minimum Temperatures:

August 21: KRDU: 76/2009 KFAY: 77/2005
August 22: KRDU: 74/2017 KFAY: 75/2018

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Most of central NC is under a Flash Flood Watch.

&&

$$

DISCUSSION...Badgett
AVIATION...Danco