606
FXUS62 KRAH 111107
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
707 AM EDT Mon Aug 11 2025

.SYNOPSIS...
High pressure centered off the Mid Atlantic coast will continue to
extend over central North Carolina this morning. This high pressure
will gradually weaken and drift southeastward through mid week,
returning our area to more typical summertime weather, with
scattered late-day showers and storms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 135 AM Monday...

* Shower/storm coverage increases today, with pockets of locally
  heavy rainfall possible.

The latest surface analysis shows a weak/diffuse frontal zone
stretching SW-to-NE through the CWA, as weakening high pressure
centered off the Mid Atlantic coast extends narrowly to the SW to
the N of the frontal zone, across our NW and far N. This front
separates surface dewpoints in the upper 60s/near 70 to its NW from
low-mid 70s to its SE, where above-normal (> 2") PWs reside. A batch
of showers over our SW continues tracking to the NW, following the
mean low-mid level flow, and looks to be further supported by moist
upglide at around 300K. The associated sloped frontal zone (evident
up through 850 mb, according to 00z UA analyses) will lift steadily
NNW today as the offshore high drifts to the SSW, allowing greater
PW to spread further into the CWA, with values nearing 125% of
normal. Forecast soundings from multiple models reveal a deep warm
cloud layer with an LCL-0C depth aoa 4 km today through tonight,
highest SE, favoring warm rain processes, and cell motions should be
somewhat slow given the weak 850-400 mb flow, toward the NW before
becoming northerly tonight with a slowly veering low level flow.
Following the CAM trends, we should see gradually increasing
coverage by late morning, peaking this afternoon into early evening,
then decreasing and pushing into our NW sections (as southerly 850
mb jetting spreads into W NC) after nightfall, potentially
correlated with an inland-tracking elevated sea breeze. Congealing
storm clusters and training cells remain possible and may lead to
isolated pockets of high rainfall totals and minor flooding. The
deep layer bulk shear will remain poor today, and SBCAPE is likely
to be mostly under 1000 J/kg, but CAPE could be higher across the N
where cloud cover will be a bit less. And with the deep warm cloud
layer and high moisture flux, high rain rates may occur. Cloud cover
and rain chances will hold down the diurnal temp range, with highs
expected to only reach around 80 to the lower 80s. Lows tonight will
be seasonable, in the upper 60s/lower 70s. -GIH

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 225 AM Monday...

The offshore surface high will have drifted down our latitude while
weakening and pushing further offshore, leaving us in a deepening S
to SW flow as weak lee troughing develops over the Piedmont.
Featured in this flow is modest but evident 850 mb jetting from the
Gulf into the western and central Carolinas, correlated with
continued above normal PW (125-135% of normal), highest across our W
and N, where models also place an area of enhanced upper divergence.
The HREF probabilities for rain are highest (55-70%) across our
southern half Tue afternoon, but given the higher PW in the NW,
potential dynamic contribution to forcing, and indicators of pockets
of 1000-1500 J/kg CWA-wide, likely pops across the entire forecast
area seems warranted. The only caveat to this is the retrograding
mid level anticyclone which drifts westward to over FL Tue,
resulting in a period of weak mid level ridging over the Carolinas
from morning into afternoon, corresponding to peak heating (although
considerable multi-layer clouds will limit that). This brief ridging
could hinder deep lift somewhat. But there are also indications in
the larger scale models that we could see MCVs from Gulf Coast
convection riding N then NE across our area late in the day through
Tue night, so will keep chance pops going through the night, near
climo W and just isolated in the E for now. We`ll start the day with
seasonable temps, so even with broken cloud decks, we should be able
to reach highs in the low-mid 80s with thicknesses just a few meters
below normal. Lows Tue night 69-75 under mostly cloudy skies. -GIH

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 355 AM Monday...

A subtropical high in the mid levels centered near FL will get
suppressed a bit to the south on Wednesday and Thursday as a couple
of shortwaves move east across SE Canada and northern New England,
rotating around a closed low centered near Hudson Bay. At the
surface, a weak Bermuda High will move farther east into the western
Atlantic as another high moves SE from Ontario/Quebec on
Wednesday/Thursday into New England by Friday. Any fronts and
widespread upper forcing will stay to our north, but there will be
weak to moderate instability and above-normal PW values (2+ inches)
each day from Wednesday through Friday as SW flow aloft around the
subtropical high results in a constant feed of moisture into the
region. There will also be a lee surface trough in place. So
Wednesday through Friday feature POPs mostly in the chance (30-50%)
range each afternoon and evening. Coverage will be less in the
overnight and morning hours due to loss of heating. Organized severe
weather is not expected to be a concern as there will be weak flow
and a lack of shear. While average QPF each day is not impressive,
any spots that receive multiple showers or storms could have a
localized flash flood risk.

Broad ridging will then set up over the Central and Eastern US over
the weekend as the subtropical high slowly drifting westward along
the Gulf Coast merges with a separate ridge originating from the
Southwest US. By Saturday and especially Sunday, the surface flow
over central NC looks to turn more northeasterly as the high moves
east of New England and ridges down the East Coast, pushing a
backdoor cold front into the Mid-Atlantic. This will begin to advect
some cooler, drier, and more stable air into our region. So POPs
decrease through the weekend, lowest in the NE, with only slight
chance POPs at best on Sunday.

As for temperatures, the hottest day of the period looks to be
Thursday with highs in the upper-80s to lower-90s and lows in the
lower-to-mid-70s. Combined with dew points in the 70s, heat indices
as high as the low-100s will be possible in the SE, but Heat
Advisory criteria is still not expected to be met. Wednesday and
Friday will be slightly cooler as forecast highs are in the mid-80s
to around 90. Temperatures will then drop further over the weekend
with highs ranging from lower-80s to upper-80s and lows in the mid-
60s to around 70. Some raw model output indicates lower-to-mid-60s
dew points will be possible by Sunday.

&&

.AVIATION /11Z MONDAY THROUGH FRIDAY/...
As of 705 AM Monday...

As expected, IFR to LIFR low stratus has finally overspread much of
central NC, and some patchy fog is also observed especially across
the Coastal Plain (including RWI). This will continue for a couple
more hours, with most places lifting to MVFR by late morning.
Guidance differs on how much scattering to VFR will occur today, so
continue to handle this uncertainty with a TEMPO group for VFR at
all TAF sites. However, it is possible that a longer period of VFR
occurs, or that very little improvement occurs at all. Scattered to
locally numerous showers and storms are also expected to move in
from south to north from late morning into early evening. While sub-
VFR conditions will be possible with any heavier showers or storms,
due to uncertainty in exactly when and where they will occur,
continue to handle this with VCSH at all TAF sites. Precipitation
will diminish later in the evening, but ceilings should begin to
lower back down to IFR after midnight, with LIFR even possible
by early Tuesday morning.

Outlook: A pattern of diurnally driven showers/storms returns
through the extended period. Isolated to scattered showers and
storms will be possible each day. Patchy fog and/or low stratus will
also be possible each morning, especially in areas where rain falls
the day before.

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Danco
AVIATION...Danco/Helock