690
FXUS62 KCHS 070552
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
152 AM EDT Tue May 7 2024

.SYNOPSIS...
Atlantic high pressure will remain across the region through
mid week. A cold front will move through the area Friday
bringing cooler conditions heading into the weekend.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
At 150 AM: KCLX indicated dry conditions across SE GA and the SC
Lowcountry. An isolated shower was detected over the outer GA
waters, tracking to the east. Looking upstream, a cluster of
showers and isolated thunderstorms was located over the northern
Midlands of SC. This activity should track across the PeeDee
basin late tonight. The updated forecast will feature dry
weather with rain-cooled temperatures in the 60s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
Tuesday through Wednesday: Mid and upper level ridging will build
across the region on Tuesday and persist into Wednesday. At the
surface, the pattern will look very summer-like with high pressure
over the subtropical Atlantic extending back to the west and into
the region. The main story during this period will be increasing low-
level thickness values and likely the warmest temperatures of the
year so far (see Climate section below). Highs are forecast to reach
the low 90s away from the immediate coast each day, with even some
mid 90s possible for Wednesday. The good news is that dew points
should mix out each afternoon, keeping heat index values only a few
degrees higher than the ambient air temperatures. Thanks to the
ridge and warm profiles, the atmosphere becomes less supportive of
diurnal convection each day. The forecast is dry, other than a small
area of slight chances in place for portions of the Charleston Tri-
County region early on Tuesday.

Thursday: Mostly a continuation of the warm up on Tuesday and
Wednesday, with highs again forecast into the low to mid 90s. The
main change is that the ridge flattens out aloft and a strong cold
front will approach the region from the northwest. While the bulk of
the day appears to be dry, by as early as the late afternoon
upstream thunderstorms could develop and begin to move into the
forecast area. The environment ahead of these storms could be
supportive of a notable severe weather threat with CAPE in excess of
2,000 J/kg and deep layer shear on the order of 30-40 knots. The
timing of the severe potential remains a bit uncertain, but the area
remains within a 15% threat area on SPC`s day 4 severe weather
outlook. The highest rain chances are across the interior, 50-60
percent, ranging to just 20s along portions of the coast.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The Thursday night and Friday portion of the period remains quite
uncertain and will depend on the progression of the cold front
through the area. Some guidance would suggest that the front does
not clear the forecast area and another round of convection could
pass through while other guidance pushes the front further south and
feature a much drier and quieter solution. Either way, the front
will be offshore by Friday night and a notable airmass change is in
store for the weekend. The forecast is dry and temperatures are
expected to be down to right around normal for mid May, and this
should continue into early next week as well.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
6Z TAFs: The terminals should remain VFR through the TAF period.
There remains some potential for the development of ground fog
around dawn this morning. Based off of radar rainfall estimates
and forecast light winds, the KSAV TAF will feature a TEMPO from
11-13Z for ground fog. Otherwise, terminals will remain dry with
southwest winds peaking during the heat of the afternoon around
10 kts.

Extended Aviation Outlook: Primarily VFR. Chances of showers
and thunderstorms will increase late Thursday through Friday.

&&

.MARINE...
At the sfc, the pattern will feature high pressure from the western
Atlantic to the northern Gulf of Mexico and a warm front across the
Ohio River Valley. This pattern should yield south-southwest
winds 10-15 kt with seas 2-4 ft through tonight.

Tuesday through Saturday: For the first half of the period, the
pattern will be quite similar to a summertime pattern with the local
waters sitting under the western edge of high pressure over the
Atlantic. The result will be south to southwest flow that surges
closer to the land/sea interface each afternoon and evening. For the
late part of the week, this will change as a cold front approaches
on Thursday and then passes through by Friday. This will support
stronger winds, and possibly necessitate Small Craft Advisories for
portions of the waters. Behind the front Friday night and into the
weekend, winds will be northwesterly though not as strong and any
ongoing advisories should end.

&&

.TIDES/COASTAL FLOODING...
The upcoming New Moon (May 8) and recent Perigee (May 5) will lead
to elevated astronomical tides over the next few days. Minor
coastal flooding is possible along Charleston and coastal
Colleton Counties, including Downtown Charleston, during the
evening high tides Tuesday through Thursday.

&&

.CLIMATE...
May 7:
KCHS: 93/1977
KSAV: 94/1977

May 8:
KCHS: 93/1986
KSAV: 96/1986

May 9:
KCHS: 95/1963
KSAV: 95/1962

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...NED
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...NED
MARINE...Adam/BSH