066
FXUS62 KCHS 042002
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
402 PM EDT Tue Jun 4 2024

.SYNOPSIS...
High pressure will extend across the area through Wednesday. A
cold front will approach from the northwest on Thursday, then
slowly move through on Friday. High pressure returns for the
weekend.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Rest of this afternoon: Radar continues to show that isolated to
scattered convection remains confined to the far interior
counties, from Allendale County, SC to Jenkins County, GA. Weak
boundaries are propagating from these areas of convection, which
will likely form isolated to scattered showers a little further
eastward, especially if any of those boundaries can reach the
seabreeze, which is currently 10 to 20 miles inland. Locally
heavy rainfall is now looking a little more likely over the
interior location due to the multiple boundary collisions and
the relatively slow storm motions.

This evening and overnight: Expect convection to steadily
decrease after sunset due to the loss of heating/instability. A
relatively mild night is expected, with minimum temperatures in
the upper 60s to lower 70s, which is actually close to normal
for this time of year.

Still not concerned about any widespread fog, but some patchy,
low level late night fog will be possible, especially within any
areas that received rainfall this evening.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday: A fairly active pattern will be in place as weak mid-lvl
ridging shifts further offshore and becomes replaced with weak mid-
lvl troughing across the Southeast United States. A series of h5
shortwaves associated with the trough will ripple across the area,
the first of which occurs on Wednesday and helps promote scattered
to potentially numerous showers/thunderstorms during peak heating
hours. A seabreeze circulation could provide an additional focus of
activity and a few stronger thunderstorms and/or isolated severe
thunderstorm can not be ruled out during peak heating hours, mainly
inland. Convection should then wane during evening hours. High temps
should range in the upper 80s to lower 90s away from the coast.
Overnight lows should range in the low-mid 70s away from the
immediate beaches.

Thursday: A southwest flow will help advect deep moisture to the
region (PWATs near 2.0 inches) ahead of a cold front advancing
toward the Southeast United States late day, suggesting the most
active weather day of the week. Numerous showers and thunderstorms
remain in the forecast during afternoon hours when stronger h5
shortwave energy arrives and the sfc front advances across the
Midlands. Although wind fields remain rather weak, moderate levels
of instability could result in a few pulse severe thunderstorms
locally, especially if thunderstorm boundary interactions occur with
an inland moving seabreeze across inland zones. Convection could
persist into evening hours as the front begins to shift across the
local area at night, posing a limited risk for a few stronger and/or
isolated severe thunderstorm closer to coastal areas before
midnight. However, the threat for stronger activity likely comes to
an end during the second half of the night as the front begins to
advance offshore. High temps for the day should range in the lower
90s for most areas away from the beaches. Low temps should dip into
the upper 60s well inland to low-mid 70s closer to the coast.

Friday: The cold front will likely reach the coast prior to
daybreak, with a deep westerly flow occurring across the region in
its wake during the day. There isn`t much in the way of cold air
advection post fropa to start off the weekend and with a substantial
downslope wind in place temps are likely to remain warm, perhaps in
the lower 90s. However, moisture will likely be driven offshore with
the front and subsidence associated with the downslope flow suggests
precip chances will remain fairly limited to southern most areas,
perhaps near the I-95 corridor across southeast Georgia. Given the
amount of heating, a few thunderstorms can not be ruled out, but
stronger/severe convection is not expected.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Although temps will remain fairly warm this weekend, the airmass
will noticeably change due to substantially lower dewpoints. This
should also limit the potential for convection. An increase in
moisture early next week and some shortwave energy will bring a
return to scattered diurnal convection.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Rest of today and tonight: VFR conditions are expected to
prevail at KCHS, KJZI, and KSAV. Still looks like the best
chance for an isolated afternoon shower/thunderstorm will be
around KSAV through the rest of the afternoon, but changes are
less than 20%.

Wednesday: Increasing chances for afternoon showers/thunderstorms.
Given 20-30% chances for convection start at the end of the
current TAF period (18z Wed), have decided to leave mention out
for now.

Extended Aviation Outlook: TEMPO flight restrictions are possible
Wednesday afternoon with showers and thunderstorms and again on
Thursday with showers and thunderstorms associated with a passing
front. VFR conditions should then prevail Friday and persist through
Sunday.

&&

.MARINE...
Rest of this afternoon: The waters will remain dominated by
Atlantic high pressure, centered to the southeast. Winds generally
from the southeast at 10 to 15 knots, strongest near the coast
with the seabreeze. There could be some gusts of 15 to 20 knots
near the coast later this afternoon. Seas expected to average
2-3 feet.

Tonight: Continued relatively quiet with southeast winds of 5 to
10 knots. Could see isolated late night showers/thunderstorms,
especially beyond 20 nm offshore.

Wednesday through Sunday: High pressure will remain over the western
Atlantic Wednesday, maintaining southerly flow around 15 kt or less
into early Wednesday night. The pressure gradient should then show
signs of strengthening heading into Thursday as a cold front
approaches from the west Thursday night into early Friday. Southwest
winds gusting upwards to 15-20 kt are possible ahead and immediately
post fropa, before the pressure gradient weakens and winds turn more
offshore heading into the weekend. Seas should also build up to 3-4
ft into Thursday night, then subside to 2-3 ft during the
weekend.

&&

.TIDES/COASTAL FLOODING...
This evening: Latest guidance and tide trends indicating that
tide levels for the Charleston Harbor site will reach near 7
feet, but there is still some uncertainty. Due to the marginal
nature of this event, have opted to hold off issuing a Coastal
Flood Advisory, but one may be necessary.

Astronomical tides will continue to rise this week. Although
meteorological conditions are not very favorable for elevated
tides, we are expecting the threat for a positive tidal anomaly
of 0.5 to 0.7 ft. Therefore, the evening high tides Wednesday
and Thursday could reach at least 7.0 ft MLLW in Charleston,
necessitating Coastal Flood Advisories.

&&

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

&&

$$

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