-- Discussion containing changed information from previous version are highlighted. --
420
FXUS62 KRAH 130738
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
338 AM EDT Thu Jun 13 2024

.SYNOPSIS...
Surface high pressure over the northern mid-Atlantic will drift east
and move off the mid-Atlantic coast this morning. An area of low
pressure will move off the east coast of Florida later today and
then lift northeast off the mid-Atlantic coast through late Friday.
A cold front will then slide southward into the area Friday night
and Saturday.


&&

.NEAR TERM /THROUGH TONIGHT/...
As of 910 PM Wednesday...

No major changes to the previous forecast with this evening update.
The 00Z upper air analyses show one week s/w over the mid-Atlantic
coast and another over the Deep South/TN Valley. The 00Z surface
analysis shows high pressure off the mid-Atlantic coast and over the
WV/western PA, with a weak trough between extending from the
Southeast US to the Northeast US along and just east of the
Appalachians. While the weather should remain dry tonight, as the
s/w to the west progresses eastward toward/into central NC tonight,
expect continued broken/overcast high clouds to persist. The
continued southeasterly return flow at the surface will keep
dewpoint temperatures in the mid 60s across much of the area, making
for a humid night as lows tonight should also be in the low to mid
60s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 230 PM Wednesday...

...This week`s heat and humidity will peak Friday...

A shortwave over the lower Tennessee Valley today will cross the
area late tonight and move offshore on Thursday while interacting
with a disturbance that the NHC is monitoring over Florida, likely
producing an area of low pressure well off the Carolina coast. That
low is not expected to develop into a tropical system at this time,
and is expected to continue to move off to the east-northeast on
Thursday, shunting the associated moisture well offshore as well.
This will leave Central North Carolina between that area of low
pressure to the east and a cold front moving through the Midwest
with a ridge of high-pressure extending southwestward from off the
mid Atlantic coast across NC.

Cirrus  associated with the upper level shortwave tonight should
gradually clear from west to east on Thursday and result in quite a
bit of sunshine again. East-northeasterly flow between the
aforementioned surface low and high-pressure should be a little
enhanced over coastal areas, but it appears interior NC wont feel
much influence and instead see a 5m increase in low level
thicknesses and modest mixing. resulting in temperatures 2 to 3
degrees warmer on Thursday  and more lower 90s in the southeast CWA.
Guidance also suggests enough mixing to keep dewpoints in the lower
60s or even some upper 50s, helping to hold back the higher heat
indices for another day.  Lows Thursday night will be in the low to
mid 60s.

Friday continues to look like the hottest day ahead of the
approaching cold front with the development of a sharp thermally
enhanced lee trough but very little deep moisture to support much
convection. If it does develop, the northern portions of the
Piedmont appear favored given initiation in the northern Foothills
into SW VA and the upper trough cross the Mid-Atlantic States.
However the relative warmth aloft looks to limit instability to less
than 1000 MLCAPE. The more recent runs of the GFS are notably more
active in the evening across the northern Piedmont in northern
coastal plain as the frontal convergence shifts through the area. It
is hard to imagine no shower at all, but we will maintain a dry
forecast overall given less favorable initial instability and diurnal
timing.  Models indicate low level thicknesses climbing by 10m over
Thursday and highs reaching to mid 90s, pushing heat indices into
the mid and upper 90s. Lows Friday night will be muggier with the
delayed timing of the front, with upper 60s and lower 70s forecast.


&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 335 AM Thursday...

NNE flow behind the cold frontal passage on Friday night and
Saturday morning will advect slightly cooler and drier air into
central NC. This will provide some relief from the heat and humidity
this weekend, but it will still be hot and slightly warmer than
normal. Forecast highs both Saturday and Sunday are upper-80s to
lower-90s, with lows generally in the 60s. Dew points will only be
in the mid-50s to lower-60s, aided by NW downsloping flow aloft
around a mid/upper ridge that will be over the Deep South. If the
progression of the cold front is slow enough, a small minority of
GFS/ECMWF/Canadian ensemble members indicate a shower or storm can`t
be ruled out in the extreme SE (mainly southern Sampson County) on
Saturday afternoon and evening, so continue slight chance POPs
there. But even this may be overdone as the forecast keeps trending
drier.

The anomalous mid/upper ridge will continue to strengthen through
the rest of the period, from 592 dam to possibly as much as 600 dam
by midweek if the 00z ECMWF is to be believed. The ridge will
initially centered to our west over the southern Appalachians on
Sunday/Monday before moving north to PA/Upstate NY and the Lower
Great Lakes by Wednesday. At the surface, high pressure will move
off the New England coast on Sunday and linger in the western
Atlantic into midweek, shifting the low-level flow over central NC
to a SE direction. This will bring increased clouds, particularly in
the west. Upslope showers and storms also may develop over the
Mountains, and while they should largely stay to our west, ensemble
probabilities indicate a few could drift into our far W or NW
counties. Thus continue slight chance POPs there each afternoon from
Sunday through Wednesday. Otherwise and elsewhere, dry air and
subsidence from the mid/upper ridge should preclude any convective
development. The building ridge will also help temperatures increase
once again, with forecast highs from Monday through Wednesday mostly
in the lower-90s and forecast lows in the upper-60s to lower-70s.
Models agree there will be enough mixing to keep dew points from
getting too oppressive (generally in the 60s), but heat indices will
still peak in the lower-to-mid-90s each day.
-- End Changed Discussion --

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
As of 255 AM Thursday...

VFR conditions are generally expected to continue across most of
central NC for the 24 hour TAF period as weak high pressure ridges
into the region with a drier than average airmass across the region.
There may be a few patches of MVFR fog in a few spots this morning,
A couple of disturbances aloft will bring some patches of cirrus
clouds across the region along with some SCT to BKN daytime
stratocumulus clouds with bases of 5-7kft that are apt to develop
during the late morning and continue into the afternoon. Mainly
light to calm winds early this morning from the southeast to east
will increase to between 4 and 8kts during the day and become
more southerly to southeasterly with very light winds tonight.

Outlook: Generally fair weather with VFR conditions are expected
through early next week. A cold front will move through the region
late Friday into Saturday and could produce a shower or storm across
the north on Friday night, otherwise generally dry weather is e
expected. Some patchy late night/early morning fog or stratus is
possible across mainly southern and eastern locations into the
weekend. -Blaes
&&

.CLIMATE...

Record High Temperatures:

June 14:
KGSO: 98/1926
KRDU: 97/1944
KFAY: 100/2022

&&

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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...KC
SHORT TERM...BLS
LONG TERM...Danco
AVIATION...Blaes
CLIMATE...RAH