760
FXUS62 KRAH 102009
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
409 PM EDT Wed Jul 10 2024

.SYNOPSIS...
A cold front will push east across central NC through this evening,
then stall out over the Coastal Plain tonight. This front will push
back westward into the Piedmont on Thursday, but will generally hold
over the region through Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 313 PM Wednesday...

A Heat Advisory remains in effect for all of central NC through 8 pm
tonight.

The sfc cold front, marked by dew points in the mid 60s and nwly
post-frontal sfc flow is currently draped along the NC Foothills.
Ahead of this feature, primarily ssely flow persists across central
NC with temps well into the lower to mid 90s and dew points in the
mid 70s (the Triad has mixed out a little bit compared to elsewhere,
and thus the Heat Indices have maxed out around 100 thus far).
Further southeast, outflow associated with weak sea-breeze
convection near Cape Fear earlier today has spawned a few showers in
our southern Coastal Plain/Sandhills the past hour or so.  Expect
this activity to persist for a few hours, but largely dissipate
quickly given no shear and weak lapse rates in that vicinity.

As the front slides through central NC later this afternoon/early
evening, isolated to scattered convection will be possible ahead of
and along the boundary.  The far western Piedmont has been primarily
stable for much of today (although some CAPE has developed in the
past few hours), and thus think rain chances will be fairly limited
there as post-frontal drier air and wly flow quickly filter in. For
those along and east of US-1, latest high-res guidance suggest there
could be enough sfc convergence along the dew point gradient to
induce scattered showers and storms in this vicinity.  The Storm
Prediction Center extended their Marginal area (which was previously
way up in VA/MD) down into our northern to central Piedmont.  While,
bulk-layer shear is expected to increase some in these areas later
this afternoon, it will likely max in the 10 to 20 kt range.
Additionally, steep low-level lapse rates and strong upper forcing
for ascent is basically absent over our area.  Thus, don`t think
we`ll see much more than perhaps an isolated stronger storm capable
of producing a stronger gust. Any lingering convection should push
east of I-95 by later tonight.

A decent gradient in overnight lows appears possible tonight, with
temps dipping near 70 (NW) to mid/upper 70s (SE).  Some patchy fog
will be possible across the far southeast as the front washes out
and mid 70s dew points may still persist there.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 140 PM Wednesday...

Aloft, the longwave trough will remain over the MS Valley through
Thu night, while the strengthening Bermuda high slowly ridges
westward. Model guidance continues to show an area of low pressure
tracking wnwwd around the Bermuda high toward the mid-Atlantic coast
Thu/Thu night. At the surface, the surface boundary should retreat
westward through central NC Thu/Thu night. Meanwhile, a low could
develop along the front off the Southeast US coast Wed night, then
drift westward into the SC Thu/Thu night. There is still some
uncertainty wrt the timing and track of that system thereafter. As
the surface boundary retreats westward and the low aloft approaches,
cloud cover and chances for showers and storms will increase over
central NC from east to west through Thu night. Rainfall amounts
remain a bit uncertain, but still expect highest amounts over the
Coastal Plain, lowest over the western Piedmont. There is still a
marginal risk for excessive rainfall Thu/Thu night across most of
central NC. Highs should range from upper 80s east to mid 90s
southwest, but with the higher dewpoints accompanied by rain and
clouds, air temps should be decreasing as dewpoints are increasing.
As a result, heat index values should top out in the mid 90s Thu.
Lows should range from around 70 degrees north and west, to mid 70s
SE.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 400 PM Wednesday...

Wet weather is expected across central NC on at least Friday and
possibly into Saturday, which will hopefully provide some welcome
relief from the drought conditions. A front that pushed back west
through central NC as a warm front on Thursday night will likely
stall somewhere around the Foothills or western Piedmont on Friday.
Rich moisture will be in place ahead of the front, with dew points
in the 70s and PW values in the 2-2.5 inch range, which is 125-150%
of normal. Meanwhile mid-level troughing off the Southeast US coast
will induce a weak surface low that moves north across SC and NC on
Friday and Friday night. The NHC gives this system only a 10% chance
of tropical development with only marginally favorable conditions,
but it will still aid with moisture and lift regardless. In
addition, a shortwave trough will swing NE from the Great Lakes into
southern Ontario/Quebec, and central NC will be in the right
entrance region of a southwesterly upper jet on the eastern side of
the trough.

Low-level convergence along the front will combine with the coastal
disturbance and jet influence to result in widespread convection on
Friday. WPC depicts a pretty sharp QPF gradient across our area,
ranging from just around a quarter inch in the far NW Piedmont to 1-
1.5 inches in the Coastal Plain. Of course, locally higher amounts
will be possible given relatively slow storm motion and potential
training that occurs. While we have been dry lately, this much rain
could still result in localized flooding issues, especially by
Friday which will be the second day in a row of potentially heavy
rain, so soils will be more saturated and FFG will be lower. Thus
WPC has a slight risk (level 2 of 4) for excessive rainfall across
most of the area on Friday. Not expecting much of any severe threat
given the lack of shear. High temperatures will be below normal, in
the lower-to-mid-80s, but lows Friday night will stay mild (lower-to-
mid-70s).

Precipitation coverage and intensity will begin to decrease on
Saturday, but exactly how much is still uncertain. The upper
disturbance will pull away, and the highest moisture axis will push
near the coast as the mid-level flow turns more WSW. At the surface,
the front over the area will start to become more diffuse, and if
the ECMWF is to be believed, the low-level flow will turn
dry/northwesterly. But the GFS and most of its ensembles keep moist
southerly low-level flow for another day and thus have greater
coverage of showers and storms. For now have chance to likely POPs
across the area, lowest NW and highest SE. Temperatures will get
back to near normal with highs in the upper-80s to lower-90s.

Sunday through Wednesday will turn drier with POPs closer to climo
(20-40%) each day, as the upper pattern gets less active and PW
values drop back to near normal. Troughing over the Great Lakes will
finally push east into northern New England and the Canadian
Maritimes, as broad mid-level ridging extends from the western
Atlantic into the Southeast US. At the surface, the stalled front
will gradually wash out as low-level flow is from a S/SW direction.
The best chances for convection will be focused near the Piedmont
trough and sea breeze. While this pattern reduces the flooding
threat, it brings back the heat. By Sunday, highs will be back in
the lower-to-mid-90s with heat indices in the upper-90s to low-100s.
Even hotter conditions are expected from Monday through Wednesday
with highs in the mid-to-upper-90s and heat indices reaching 105-110
possible from around the Triangle south and east.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
As of 104 PM Wednesday...

VFR conditions will persist ahead of an approaching cold front
currently draped over the mountains. Isolated to scattered showers
and a few storms will likely develop along and ahead of the front as
it pushes west to east across central NC through tonight. These
could produce brief sub-VFR and gusty conditions with the best
chances at KRDU/KFAY/KRWI later this afternoon. However, confidence
was a bit too low to include more than VCSH at these sites with this
TAF package. Otherwise expect some decent sly sfc flow for this time
of year rest of today (10 to 20 kt gusts at times). Flow will turn
wnwly with cold front passage through early Thursday morning. Some
fleeting MVFR stratus may be possible at KRWI early Thursday
morning. Elsewhere should remain VFR.

Outlook: The front will stall over the Coastal Plain Thursday into
Saturday inducing increasingly wet weather and potential for adverse
aviation conditions especially for eastern TAF sites. The pattern
should shift to diurnally-driven convection by Sunday.

&&

.CLIMATE...

Record High Temperatures:

July 10:
KRDU: 99/1993

July 15:
KGSO: 97/1974
KRDU: 99/1997

July 16:
KGSO: 99/1915
KRDU: 101/1887
KFAY: 103/1937


Record High Minimum Temperatures:

July 10:
KGSO: 77/1981
KRDU: 77/1981
KFAY: 77/1998

July 11:
KGSO: 75/1992
KRDU: 77/1981
KFAY: 76/2019

July 12:
KGSO: 76/2011
KRDU: 78/2011
KFAY: 80/1935

July 13:
KGSO: 75/2017
KRDU: 78/2017
KFAY: 78/2017

July 14:
KGSO: 77/1981
KRDU: 77/2017
KFAY: 80/2017

July 15:
KGSO: 74/2019
KRDU: 76/1992
KFAY: 78/2015

July 16:
KGSO: 75/2010
KRDU: 77/2010
KFAY: 78/1992

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM this morning to 8 PM EDT this evening for
NCZ007>011-021>028-038>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...KC
LONG TERM...Danco
AVIATION...Luchetti
CLIMATE...RAH