770
FXUS62 KRAH 030616
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
205 AM EDT Wed Jul 3 2024

.SYNOPSIS...
Canadian high pressure centered just offshore the Middle Atlantic
coast will linger over the Carolinas through tonight. A subtropical
ridge will otherwise extend across the South Atlantic states through
the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 920 PM Tuesday..

Forecast is in good shape with very few changes needed. Surface high
pressure centered near NYC at this hour will continue to extend down
through our area while drifting slowly eastward. Minor mid level
perturbations are seen in layer WV imagery moving SE over our
region, but with a very dry column (00z GSO PW near the 10th
percentile) and stable mid levels, little more than a few mid clouds
will be observed through tonight. Still expect lows tonight in the
upper 50s to lower 60s. -GIH

Earlier discussion from 145 PM: As surface high pressure currently
centered over the Northeast continues to slowly slide offshore this
afternoon, quiet weather will continue across Central NC. Dew points
today have been in the 50s across the region, with onshore moisture
moving in later this evening dew points will get into the 60s later
tonight especially in the eastern portions of the Piedmont and
Coastal Plain region. High temperatures will top out this afternoon
in the mid 80s with a few areas in the south getting into the upper
80s. Lows overnight will be slightly warmer than last night ranging
from low to mid 60s.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 230 PM Tuesday..

Continued dry on Wednesday under the influence of a 1024mb high off
the Mid-Atlantic coast and and eastward shifting 595dm sub-tropical
at 500mb over the Deep South.  As the surface high shifts eastward
as well, return flow will begin to kick in, but likely not until
late in the day, delaying the return of upper 60s and lower 70
dewpoints until Thursday.  1000-850mb thicknesses rise 15-20m over
today`s expected values, which will result in highs in the upper
80s and lower 90s, coolest in the northeast away from the thermal.
ridge.

With southerly return flow becoming established Wednesday night,
guidance suggests some stratocu across the foothills and drifting
into the western Piedmont, with otherwise quiet weather and lows
likely to range from the upper 50s east to lower 60s west.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 355 PM Tuesday...

A mid-level anticyclone stretching from the Southern Plains to the
Deep South will gradually shift east to off the Southeast US coast
from Thursday into early next week as a series of shortwaves moves
from the Northern Plains into the Northern Great Lakes and Southeast
Canada. While the shortwaves will stay well north of us, increasing
southwesterly flow aloft between a mid-level trough that sets up to
our west and the ridging to our east will bring in PW values
exceeding 2 inches from Thursday through Tuesday. The first
shortwave will drag a cold front to its south that reaches the
Appalachians by Saturday night, but models depict it washing out
before it reaches our area. Even still, the surface flow will become
south/southwesterly ahead of the front as high pressure initially
just east of NC on Thursday continues to push farther east near
Bermuda. This will increase dew points into the upper-60s to lower-
70s on Thursday, then lower-to-mid-70s from this weekend into early
next week. With better moisture and instability in place along with
a lee surface trough setting up, shower and storm chances will
return each afternoon and evening, mainly over the northern and
western Piedmont on Thursday then areawide from Friday through
Tuesday. The greatest ensemble probabilities for precipitation are
in the NW on Friday and Saturday, shifting more to the south and
east for the rest of the period. The storms look to be more of the
pulse variety given the lack of shear, so widespread severe weather
is not expected.

The biggest story during the period will be the temperatures, which
are expected to reach the mid-to-upper-90s in most places from
Thursday through Saturday. The current forecast comes within 2-3
degrees of the daily records highs at all three climate sites (GSO,
RDU and FAY), as seen in the climate section below. Lows won`t
provide a lot of relief either, only dropping into the mid-to-upper-
70s. Heat indices of 100-105 will be possible on Thursday, and basic
heat precautions should still be taken especially given the
Independence Day holiday with a lot of people spending time
outdoors. But Friday and Saturday look to be the hottest and most
humid days of the period, when heat indices of 105-110 are expected
from around the Triangle south and east. Heat Advisories will likely
be needed on these days. At least a slight moderation is expected
from Sunday through Tuesday, but exactly how much we cool down is
still uncertain. The raw GFS and ECMWF depict some highs in the 80s,
but their ensembles aren`t as cool, and would like to see more
consistency before lowering forecast temperatures too much.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 210 AM Wednesday...

The presence and influence of Canadian high pressure that will
extend from just offshore the Middle Atlantic coast southwestward
into the Carolinas will favor mostly VFR conditions in cntl NC
through Thursday morning. While a brief period of visibility
restrictions cannot be entirely ruled out at RWI around daybreak,
the likelihood seems relatively low given the foregoing
Canadian/continental air that would favor more dew than fog, should
surface temperatures even radiationally cool sufficiently amid areas
of ~ 6 thousand ft AGL stratocumulus that are apt to persist there.

Outlook: A chance of showers/storms will exist over the wrn NC
Piedmont (INT/GSO) Thu afternoon-evening and throughout cntl NC Fri
through the weekend.

&&

.CLIMATE...
Record High Temperatures:

July 4:
KGSO: 98/1970
KRDU: 101/2012
KFAY: 98/2019

July 5:
KGSO: 98/2012
KRDU: 102/1999
KFAY: 101/2002

July 6:
KRDU: 102/2022
KFAY: 99/1990


Record High Minimum Temperatures:

July 4:
KGSO: 73/2018

July 5:
KGSO: 74/1999
KRDU: 78/1902
KFAY: 77/2005

July 6:
KGSO: 76/1999
KRDU: 79/1900
KFAY: 76/2017

July 7:
KGSO: 73/2019
KRDU: 77/1900
KFAY: 78/2017

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...Hartfield/CA
SHORT TERM...BLS
LONG TERM...Danco
AVIATION...MWS
CLIMATE...RAH