986
FXUS62 KRAH 090704
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
304 AM EDT Wed Jul 9 2025

.SYNOPSIS...
Disturbances in unseasonably moist, southwesterly flow aloft will
interact with a surface trough over the Middle Atlantic and
Carolinas through Thursday.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 300 AM Wednesday...

* Scattered flash-flooding is expected this afternoon through late
  this evening, especially in urban areas of the Piedmont (including
  the Triad) as well as the hydrological sensitive areas of the
  eastern Piedmont from Chantal rainfall.

* Flood Watch in effect for a majority of the central NC Piedmont
  and western Sandhills from 2 PM today until 2 AM tonight.

Convectively amplified shortwaves are expected to ripple through the
base of the broad mid/upper level trough currently stretching from
the Great Lakes through the Ohio Valley and into the ArkLaTex
region. This will result in weak but gradual H5 heights falls to
leak into the Mid-Atlantic this afternoon through the overnight
period. Anomalous deep layer moisture will gradually increase to
around 2" areawide (exceeding the 90th percentile) and prime the
area for efficient heavy rainfall showers/storms during the
afternoon. Showers and storms are expected to develop along the
eastern slopes of the mountains and over western NC and gradually
shift eastward into central NC through mid-afternoon.

The likely greatest concern through tonight will be for scattered
instances of flash-flooding this afternoon through late this
evening. Anomalous deep-layer moisture, weak steering winds, a deep
warm-cloud layer >10,000 ft, and moderate to strong instability are
all very favorable ingredients for flash-flooding. Additionally, the
eastern Piedmont is still hydrological sensitive due to rainfall
from Chantal (soil moisture still 50-70% and FFG of around 2.5" in 6
hours). 00z HREF and the 18z REFS continue to indicate 40 to +60%
probabilities for >3" in 24 hours, but investigating the LPMM
fields, these areas of locally enhanced rainfall will likely be
scattered in nature in concentrated areas. The limited coverage of
these amounts in available guidance precludes higher probabilities
for flash-flooding at this time. Observational trends will be
assessed through this afternoon whether a moderate risk for excessive
rainfall (Level 3 out of 4) will be needed. Finally, even with
continued weak synoptic support for showers/storms to continue
overnight, available guidance still shows a noticeable weakening
trend to convective intensity from 03-06z. As such, will opt to not
extend the Flood Watch through the overnight hours at this time.

There is also a risk for wet-downbursts and convective clusters
along a common cold pool, which may result in isolated damaging wind
gusts. Downed trees and potential property damage may be locally
enhanced over the eastern Piedmont where still heavily saturated
soils would provide little resistance to even sub-severe wind gusts.
Temperatures in the low 90s and dew points in the mid 70s will
result in another hot and humid day with heat indices mostly ranging
from 100 to 104. Although brief periods of time when 105 will be
possible, short temporal duration and patchy areal coverage will
preclude the need for a heat advisory with the early-morning
forecast update.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 249 PM Tuesday...

The short term forecast discussion will be updated shortly...

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 125 PM Tuesday...

The chance of showers/storms will continue to be high in the
extended forecast, although a wash-out over several days is not
expected. Coverage should be the greatest on Thursday as an upper
trough is over the Ohio Valley, with 80-90% chances of storms across
all locations. After this, the upper flow becomes a bit more zonal
in nature, which should help to decrease the chances of
showers/storms each afternoon/evening. Once an upper high begins to
develop over the eastern Gulf Sunday into Monday, this will pump
additional moisture into the area, resuming the higher chances for
showers/storms.

Thursday remains under a marginal (level 1 of 5) severe thunderstorm
risk from the Storm Prediction Center - despite meager wind shear,
there should still be warm and moist enough conditions to prompt
some isolated severe thunderstorms. As for temperatures, values
should be relatively close to seasonal values, with highs in the
upper 80s/lower 90s and lows in the low to mid 70s..

&&

.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
As of 105 AM Wednesday...

Minor tweaks were made to the 06z TAFs. VFR conditions begin the
forecast period with SCT MVFR beginning to develop in between the
FAY, RDU, and RWI terminals. This appears co-located where the
heaviest rain fell this past afternoon. How this expands is
uncertain, but a slow development of MVFR to IFR cigs is expected,
especially around sunrise. Slow improvement through the morning
hours with scattered to locally numerous showers/storms expected to
develop over western NC by early afternoon (16-18z) and slowly shift
eastward through midnight. Timing of TEMPOs at GSO, INT, and RDU for
storms was tweaked based on latest hi-res guidance timing.

Outlook: Scattered storms are expected each afternoon and evening
through Fri, as a weak upper trough slowly approaches from the west;
greatest coverage through the outlook period may be Thurs. Early
morning fog and/or stratus will also be possible. Storm coverage
decreasing a bit this weekend as westerly flow aloft takes hold.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 2 PM EDT this afternoon through late tonight
for NCZ007>010-021>025-038>040-073>076-083>086.

&&

$$

SYNOPSIS...MWS
NEAR TERM...Swiggett
SHORT TERM...Danco
LONG TERM...Green
AVIATION...Swiggett/MWS