509
FXUS62 KRAH 051010
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
610 AM EDT Sat Jul 5 2025

.SYNOPSIS...
High pressure will build across and offshore the Middle Atlantic
today. A coastal front will strengthen and move inland across the
Carolinas tonight, ahead of Tropical Depression Three that will
drift northward into SC Sunday and into eastern sections of NC
Monday.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 245 AM Saturday...

* Comfortable humidity levels with seasonal highs
* Chances for isolated to scattered storms along/east of US-1

High pressure off of Delmarva and south of New England will
gradually shift off into the north Atlantic. Current Tropical
Depression 3 off the southeast coast is forecast to reach the
central coast of SC by early Sun as soon to be Tropical Storm
Chantal. The majority of the daytime today will be rather pleasant,
outside of a few storm chances in the east. Dewpoints should mix out
again to more comfortable levels in the lower 60s over the Piedmont
as a dry ENE flow persists. Highs will be in the upper 80s to near
90 so it will still be warm, but noticeably nicer humidity-wise.

Convective bands tied to TD 3 are forecast to move westward from the
coast during the aftn/eve as moisture transport builds inland north
of the center. Most of the CAMs show limited instability from the
drier air across the western Piedmont. That said, areas along/east
of US-1 and especially the Sandhills to Coastal Plain have the best
chance for seeing these isolated to scattered storms.

By sunset, there could be a lull in storm activity as stability
takes shape. However, areas of showers with embedded thunder should
build north and west across central NC by early Sun as PW`s increase
well above normal to 2.2-2.3 in, coincident with deep low-level
moisture transport on the NE side of TD 3. This will favor
increasing clouds Sat evening/night, with lows above normal in the
upper 60s to low 70s.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 245 AM Saturday...

* TD 3 brings marginal risk of flash flooding.
* A low-end tornado threat is possible for eastern sections of
  central NC, but we are currently not outlooked from SPC

While there is still a little bit of spread in the track and timing
of TD 3, the latest NHC track forecast takes the system from SC Sun
morning into eastern portions of the Triangle by early Mon. The
NAM/GFS/HRRR/NEST appear slower and further south closer to the
coast than the ECMWF/CMC. Regardless, deep moisture transport/WAA
and very high PW`s of 2.25-2.5 in will favor the development of
widespread showers and embedded storms, maximized during peak
heating in the late morning through the evening hours. A consensus
of ensemble guidance would suggest rainfall totals through early Mon
of 0.25 to 0.5 inches west of the Triangle and 0.5 to 1 inch
along/east of US-1. Embedded higher totals of 1.5 to 2+ inches are
possible along the Coastal Plain and eastern Sandhills. The area
along/east of US-1, where WPC has retained a marginal risk of
excessive rainfall, is where the risk of flash flooding appears
highest. This could certainly be adjusted if the track changes, such
that if the American models verify, the western Piedmont could see
little if any rainfall. Highs will generally be in the 80s, tempered
by clouds/storms.

In addition to the heavy rainfall threat, while not as clear cut,
there does appear to be a low-end tornado threat for areas from the
eastern Sandhills to Coastal Plain. Some HREF members are
highlighting the potential for some updraft helicity swaths on the
northeast side of the system, in a region of 1500 J/kg of
instability. The low-level shear does appear less clear cut but
given the juicy boundary layer it is worth mentioning. A further
inland track would bring this threat further west, while a track
just inland of the coast would limit the tornado threat to mainly
Sampson County. Scattered showers/storms will continue Sun night,
mainly for eastern areas and cannot rule out that low-end tor threat
as well. Lows will be muggy in the low/mid 70s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 250 AM Saturday...

* The remnants of Tropical Depression 3 are expected to be moving
  north across central and especially eastern NC on Monday morning
  and then begin to dissipate. Showers and thunderstorm near and
  east of the circulation center will spread northeast during the
  day. Locally heavy rain and a limited risk of a strong storm are
  expected during the day into the evening with the threat largely
  confined to the Coastal Plain and Sandhills with impacts rapidly
  diminishing from east to west across the PIedmont.

* High temperatures are expected to surge on Tuesday highs in the
  wake of the tropical cyclone climbing into the lower and mid 90s
  with maximum heat index values as high as 100 to 105.

* Otherwise, chances of mainly afternoon and evening storms increase
  during the work week with the greatest chance of showers and
  storms on Thursday and Friday.

The remnants of Tropical Depression 3 are expected to be moving
north across central and eastern NC on Monday morning before the low
fills and dissipates Monday night into Tuesday across eastern NC.
Given the pattern, precipitation should be skewed near and right of
the low track, perhaps focused near the convergent flow near the
circulation center and near an inverted trough or coastal front will
extend northeast from the surface low. While locally heavy rain is
possible, areawide rainfall amounts on Monday and Monday night will
average a half inch or less east of U.S. route 1 and less than a
quarter of an inch to the west. The threat of severe weather and
perhaps a tornado appears limited but non zero and will need to
monitor the track and the evolving environment for this risk.

In the wake the tropical cyclone, a hot and humid day is expected on
Tuesday. With morning low level thickness values in the 1420s,
afternoon highs should climb well into the lower to mid 90s. A few
of the normally hotter spots such as Maxton and Raleigh could climb
into the upper 90s. Wet soils and enhanced cloud cover across the
east near Fayetteville and Goldsboro could limit highs by a few
degrees. With afternoon dew points mainly in the upper 60s to lower
70s, perhaps some mid or even upper 70s across the Coastal Plain and
Sandhills with the wet soils, heat index values will peak between
100 and 105 degrees.

The main westerlies typically confined to near the U.S./Canadian
border in mid summer dip into the Great Lakes and OH Valley for
Wednesday through Friday. In addition, a cold front will approach
the region from the north and linger on Thursday and Friday. This
pattern will result in an increasing risk for mainly afternoon and
evening showers and storms during the period, with the greatest risk
on Thursday and Friday. Highs in the lower 90s on Wednesday will
relax into the upper 80s to lower 90s given the increased cloud
cover and scattered precipitation. -Blaes
&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
As of 610 AM Saturday...

There is reasonably high confidence in VFR for the start of the TAF
period. ENE winds will pick up this afternoon, with gusts of 15 to
20 kt at RDU, FAY, RWI ahead of Tropical Depression 3. Convective
bands tied to this depression could impact RDU, FAY, RWI in the 18
to 00z period, with the highest confidence at FAY and RWI. For now,
given continued low confidence overall, have kept PROB30 in the TAF.
A TEMPO group may be needed for FAY and RWI with later updates.
Increasing moist flow tonight north of TD 3 should favor gradual
lowering of ceilings to MVFR/IFR, and isolated showers/storms, by
Sun morning between 04 and 10z, earliest at FAY and latest at
GSO/INT.

Outlook: Showers and storms, flight restrictions, and breezy nely
flow will further increase Sun as the remnants of now Tropical
Depression 3 move nwd across the Carolinas through Mon, with the
greatest impacts expected at FAY, RWI, and RDU. A humid airmass will
then favor areas of morning stratus and fog and afternoon-evening
showers/storms through most of next week.

&&

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

&&

$$
SYNOPSIS...Kren/MWS
NEAR TERM...Kren
SHORT TERM...Kren
LONG TERM...Blaes
AVIATION...Kren/MWS