267
FXUS62 KRAH 200458
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
100 AM EDT Fri Sep 20 2024

.SYNOPSIS...
An upper level trough along the East Coast will shift slowly
eastward and offshore through Saturday morning, as a weak surface
high pressure ridge extends from New England down through the
central Carolinas. An upper level disturbance will track southeast
through the Mid Atlantic region late Saturday through Saturday
night. An upper level high pressure ridge will then build in from
Texas across the Gulf and Southeast states through early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 944 PM Thursday...

The upper trough axis has shifted offshore this evening, with
primarily nwly flow over central NC.  A residual embedded mid-level
impulse continues to generate some weak convection in the NC/VA
mountains/foothills.  While most of this activity should wane and
stay out of our area, an isolated shower may trickle into the Triad
over the next hour or so.  Otherwise, expect dry conditions
overnight with lows in the lower to mid 60s.

More concerning tonight is the potential for areas of dense fog. A
few sites across the central to northern Piedmont have shown lower
visibility from fog in the past hour or so. Given clear conditions
tonight and residual anomalous moisture over the area, we`ll likely
see dense fog increase in coverage over much of the Piedmont
especially closer to sunrise (~08 to 12Z).  Will have to monitor
overnight, but a dense fog advisory may be needed for portions of
the Piedmont.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 105 PM Thursday...

Aloft, the trough off the mid-Atlantic coast will continue to shift
ewd over the Atlantic, allowing high pressure to ridge enewd into
the area. A lobe of vorticity in the upper levels will swing sewd
through central NC Fri morn/aft, while a trailing mid-level
disturbance follows Fri aft/eve. At the surface, a low will continue
to meander off the northern mid-Atlantic/New England Coast Fri/Fri
night, while high pressure ridges swd through central NC. Some lower
dewpoint air should push into the far northeast portions of central
NC as the high ridges in. While widespread convection is not
anticipated, if showers do develop, the best chance would be over
the western Piedmont during the morn/aft with the passage of the
vort max aloft, and over the northeast Piedmont/northern Coastal
Plain during the aft/eve, generally along the dewpoint gradient as
the high ridges swd. The NAM does have some MUCAPE in the 500-1000
J/Kg range Fri morn through the eve, thus an isolated storm or two
is still possible if/where convection occurs. Highs should generally
range from around 80 degrees NE to mid 80s south, with lows in the
upper 50s to mid 60s expected.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 325 PM Thursday...

Saturday morning, surface high pressure will be centered over
eastern Canada with a pressure ridge extending all the way to the
Gulf Coast. A weak front will move across the area Saturday night.
Am not terribly impressed by the depth of the moisture with the
front, but there are too many models, deterministic and ensembles,
to keep a dry forecast in that time period. Rainfall does not appear
to be substantial, but have gone ahead and added slight chance pops
across the northern half of the area. Sunday and Monday continue to
have a dry forecast as high pressure reestablishes itself, with just
the Triad being clipped on Tuesday with a slight chance of showers
in advance of the next front. Low pressure will move across the
Great Lakes during the middle of the week, and it currently appears
that the most likely timing for any showers or thunderstorms with
the upcoming cold front will be Wednesday night. Highs will be
slightly above normal for the weekend, then drop a few degrees below
normal for the weekdays. Lows will be near normal through the
extended period.
&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
As of 100 AM Friday...

The chance for MVFR-IFR fog remain high early this morning (mainly
07z-14z), due to warm moist air and very light winds near the
ground. Areas of mid clouds currently cover the far W Piedmont
(including GSO and esp INT) as well as our NE sections, which is
helping to keep fog from becoming too widespread so far, however as
these mid clouds continue to push southward and break up, widespread
dense fog and areas of low cigs in stratus are likely. There are no
strong indicators favoring one particular terminal over another for
dense fog formation, but most guidance indicates the best chances
are E of the Triad, including RDU/RWI/FAY which have all seen some
rain in the last 24 hours to further moisten the ground. A gradual
dispersion and mixing out of fog/stratus will result in a trend to
VFR conditions by 16z, persisting through early tonight. Isolated
showers are possible later today, but overall the vast majority of
the area will stay dry. Surface winds will remain light (under 10
kt) mainly from the NE or ENE through tonight.

Looking beyond 06z Sat, another round of areas of early-morning fog
and stratus producing sub-VFR conditions is possible 08z-14z Sat
morning across central NC terminals, otherwise VFR conditions are
favored to dominate through early Sun night. A backdoor front will
drop through NC Sun night as high pressure noses in from the north,
bring another chance of sub-VFR conditions early Mon morning and
again early Tue morning. Mostly dry weather will persist, however,
through Tue. -GIH

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Luchetti
SHORT TERM...KC
LONG TERM...Green
AVIATION...Hartfield