656
FXUS62 KCHS 151747
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
147 PM EDT Mon Jul 15 2024

.SYNOPSIS...
Atlantic high pressure to the east and a weak inland trough
will extend across the region through the middle of this week.

&&

.NEAR TERM /THROUGH TONIGHT/...

This afternoon: Temperatures are very hot in most locations,
even closer to the coast. Most areas now reporting temperatures
of 94 to 98 with dewpoint temperatures of 74-78, some even
around 80, especially closer to the coast. This all translates
to pretty solid Heat Advisory conditions many locations. Still
expect to touch Excessive Heat Warning Criteria between now and
4 or 5 pm in the warned area.

Thunderstorms: Currently getting isolated storms developing down
the middle of the CWA, right where previous forecast had them,
and where all convective models initiated convection. Expect
convection to continue increasing, with scattered showers and
thunderstorms, generally either side of an axis centered along
I95. Given high MLCAPE values of 2000-2500 J/Kg, and DCAPEs
around 1000 J/Kg, isolated severe storms still a threat, with
the main impact being strong/damaging winds up to 60 mph.

Overnight: Convection is expected to dissipate within a few
hours after sunset. Then, warm and humid conditions will
persist overnight. Lows will range from the mid 70s well inland
to the lower 80s at the beaches and Downtown Charleston.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: The region will be positioned along the western
periphery of high pressure both aloft and at the surface,
centered in the vicinity of Bermuda. The southwesterly flow
aloft will allow PWATs to increase to around 2.2 inches. With no
significant synoptic forcing, afternoon showers and
thunderstorms will initiate with the inland progression of the
afternoon sea breeze and other mesoscale boundary interactions.
Scattered to widespread showers and thunderstorms will be
possible. MLCAPE values are forecast to be upwards of 1500 J/kg,
so a strong to marginally severe thunderstorm cannot be ruled
out, with damaging wind gusts the main hazard. High temperatures
are forecast to reach into the low 90s along the coastline,
with mid to upper 90s further inland. Humid conditions will
persist across the forecast area, leading to heat index values
between 106-110F. A Heat Advisory may be required for portions
of the forecast area. Overnight temperatures will provide little
relief, only dipping into the mid 70s inland, with upper 70s to
around 80 along the coastline. The record high minimum
temperature could be challenged at any of the three climate
sites, see the Climate section for more details.

Wednesday: The high pressure aloft and at the surface will
begin to retreat eastward into the Atlantic as a mid-level
trough begins to progress eastward across the Midwestern states.
At the surface a cold front will also begin its trek eastward.
The local forecast area will be positioned along the southern
periphery of the mid- level trough. With some of the additional
synoptic forcing coverage of afternoon showers and thunderstorms
will likely increase from previous days, with PoPs generally
around 70% in the afternoon. MLCAPE values will again be upwards
of 2000 J/kg, leading to the threat of a strong to marginally
severe thunderstorm. There is also the threat of heavy rainfall,
with PWATs increasing to around 2.3- 2.4 inches. Once again
temperatures are forecast to reach into the low 90s along the
coast with mid to upper 90s further inland. Humid conditions
will persist, with heat index values peaking around 106- 109F
and another Heat Advisory may be required. However, with the
increasing coverage of afternoon showers and thunderstorms these
heat index values may not be realized. Overnight lows will
again only dip into the mid 70s inland, with upper 70s to around
80 along the coastline.

Thursday: The aforementioned mid-level trough will prevail
aloft, extending roughly from the Great Lakes southward into the
Deep South. At the surface a cold front will continue its slow
approach towards the local forecast area. Another wet afternoon
is forecast, with scattered to numerous showers and
thunderstorms. PWATs and MLCAPE values will be similar to
Wednesday, so the threat of strong to severe storms and heavy
rainfall exists. Temperatures are forecast to be a degree or two
lower than Wednesday, yielding heat index values of 104-106
with a few spots reaching 108F. A Heat Advisory is possible,
however the current forecast does not show enough coverage to
warrant one.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Broad troughing aloft will prevail into the weekend, with high
pressure extending into the forecast area from the Atlantic late
this weekend. At the surface a front is forecast to linger in
the vicinity of the Carolinas. With PWATs remaining elevated and
lingering forcing from the nearby front, in addition to the
afternoon sea breeze circulation, will yield a wet few days.
Guidance continues to be rather bullish with PoPs, so the
current forecast maintains chance to likely PoPs, still above
climatology. With above normal precipitation chances and
increased cloud cover through the period temperatures are
forecast to return to near normal, or even slightly below normal
through the weekend.

&&

.AVIATION /18Z MONDAY THROUGH FRIDAY/...

15/18z TAF Discussion:
KCHS/KJZI/KSAV: VFR conditions expected to prevail. Scattered
showers/tstms starting to develop just west and north of KCHS
and KSAV. Continued with VCTS for both KCHS and KSAV and no
mention of convection of KZJI, since expect storms to remain
inland of that terminal. May need to add prevailing and/or tempo
groups for convection for KCHS and KSAV this afternoon,
depending on latest radar trends.

Extended Aviation Outlook: Scattered afternoon showers/tstorms
could produce brief flight restrictions at all terminals through
the middle of next week. Late week precipitation chances will
begin to increase, increasing the risk for flight restrictions.

&&

.MARINE...
This afternoon: No significant changes were made with the early
afternoon update. Winds generally southwest 10 to 15 knots
through the afternoon. They could be slightly higher near the
coast behind the seabreeze. Seas 3-4 ft.

Tonight: Another nocturnal surge is possible tonight with
southwest winds 15 kt with gusts to 20 kt. Seas will average 3-4
ft.

Tuesday through Friday: High pressure will prevail across the
marine zones through the middle of the week. Thereafter, a cold
front will approach the inland zones, creating a slightly
pinched pressure gradient between the approaching cold front and
the high pressure over the marine waters. Overall, conditions
are expected to remain below Small Craft Advisory criteria.
However, there is a chance that the Charleston nearshore waters
could see wind gusts to 25 knots on Wednesday afternoon.
Otherwise, generally S winds are forecast, 10- 15 knots.
Slightly stronger wind speeds are possible along the direct
coastline in association with the afternoon sea breeze. Seas
should average 3 to 4 ft.

&&

.CLIMATE...
1.72 inches of rain fell at the Charleston International Airport
(KCHS) Sunday. This broke the daily rainfall record of 1.42
inches set in 2011.

Record High Temperatures:

July 15:
KCHS: 99/1986
KCXM: 100/1932
KSAV: 101/1981

Record High Minimum Temperatures:

July 15:
KCHS: 81/1981
KCXM: 82/2023
KSAV: 80/1981

July 16:
KCHS: 78/2023
KCXM: 82/2021
KSAV: 82/1883

July 17:
KCHS: 78/2023
KCXM: 82/2021
KSAV: 80/1883

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory until 8 PM EDT this evening for GAZ101-116>119-
     137>141.
SC...Heat Advisory until 8 PM EDT this evening for SCZ042>045-047-
     051.
     Excessive Heat Warning until 8 PM EDT this evening for
     SCZ048>050-052.
MARINE...None.

&&

$$

NEAR TERM...RFM
SHORT TERM...
LONG TERM...
AVIATION...RFM
MARINE...RFM