Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 051940
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
340 PM EDT Fri Jun 5 2020

.SYNOPSIS...
The area will remain between Atlantic high pressure and a
trough of low pressure inland through this weekend. A cold
front will stall over the region by early next week, then will
gradually dissipate through the middle of next week. Another
weakening cold front could approach the area late next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Subsidence over the local area has limited cumulus development
and convection much of the afternoon. However an upstream
shortwave is driving more organized convection across the SC
Midlands. This activity is expected to slowly drop southeast
into the area late this afternoon and early evening. Instability
is somewhat limited over the area and once we lose daytime
heating early this evening, conditions will become even less
conducive to sustained convection. We show a temporary increase
in PoPs through early evening across the inland half of the area
tapering off to slight chance overnight as upstream convection
tapers off. It will be mild with lows mainly in the lower to
mid 70s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday and Sunday: A typically moist environment featuring PWAT
values ranging from around 1.75 inch N/NW to around 2 inches S/SE,
max MLCape values as high as 1500-2000 j/kg and sea breeze
convergence should support isolated/scattered showers/thunderstorms,
especially during the afternoon/evening hours. The only notable
change during the weekend is that the moisture gradient is expected
to pivot to a more N/NE to S/SW orientation Saturday night and
Sunday, so Sunday PM PoPs are highest across southern/inland
counties. Through the weekend, max PoPs are capped around 40 percent
during the afternoon/evening, although as usual locally greater
coverage of thunderstorms is possible for a few hours each afternoon
evening. The potential for brief/pulse severe weather and highly
localized excessive rainfall should remain low. saturday night/early
Sunday, per normal diurnal trends coverage of convection should
decrease, and many areas could remain rain-free. High temps both
days will average in the mid/upper 80s most areas, except for lower
80s on the beaches and around 90 at a few locations well inland.
Hourly temp trends will depend on timing/location of thunderstorms.
Lows in the lower to middle 70s should be common Saturday night.

Sunday night and Monday: A weakening cold front will push into the
region from the NE, and this front should weaken/stall over the
area. This boundary should combine with the sea breeze to act as the
focus for isolated/scattered showers/thunderstorms. Since the
eventual position of the stationary front remains somewhat
uncertain, the location/best coverage of convection also remain
somewhat in doubt. For now, highest PoPs 40-50 percent remain over
southern/inland counties Monday afternoon. otherwise, high
temperatures outside convection should range from the middle/upper
80s north to the upper 80s/lower 90s south/inland.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Tropical low pressure is anticipated to shift north and inland
across the Mississippi River Valley Monday night through Wednesday
before phasing with a low pressure trough advancing across the
Central United States mid to late week. As this occurs, a stalled
front near or in the area will eventually transition into a warm
front, but will struggle to advance north due to high pressure
filtering into the area from the Atlantic mid to late next week.
Given the uncertainty in the position of the front and moisture
content, chances of precip will remain in the forecast mid to late
week. Highs will generally range in the mid/upper 80s throughout the
week while lows remain mild each night, typically ranging in the
upper 60s/lower 70s.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A few showers are possible around KSAV through the afternoon.
Mainly dry at KCHS until late this afternoon when some SC
Midlands convection may make a run for the terminal. Generally
dry overnight. Isolated convection again Sat afternoon, mainly
beyond 18Z.

Extended Aviation Outlook: Tempo flight restrictions are possible at
both CHS and SAV terminals, mainly during afternoon showers or
thunderstorms through early next week. Otherwise, mainly VFR.

&&

.MARINE...
The SW gradient will be slightly enhanced overnight with
sustained winds 15-20 kt over the Atlantic waters. Winds in
Charleston Harbor should diminish to less than 15 kt this
evening as the sea breeze subsides.

Southerly flow will persist over the waters through Sunday as
high pressure remains east of the waters. A cold front will then
shift into the waters before weakening/stalling over or near
the area into the middle of next week. Between the post-fropa
high pressure to the N/NE and the dissipating stationary front,
prevailing winds will turn onshore into midweek. In general,
winds/seas will remain below Small Craft Advisory levels through
the period, but winds could peak near 20 kts around the times
of the afternoon sea breeze and during noctural surges
especially Saturday and Sunday. Seas 2-3 ft will build to 3-5 ft
Saturday night into early next week.

&&

.TIDES/COASTAL FLOODING...
Lingering affects of the recent lunar perigee and full moon will
continue to contribute to elevated tides into early next week. Minor
coastal flooding will be possible during the evening/nighttime high
tides, especially along the South Carolina coast.

We issued a Coastal Flood Advisory for the SC coast for the 9pm
high tide. It will take less than a +0.3 ft anomaly to reach
7.0 ft and we`re on track to hit 7.0-7.2 ft MLLW.

&&

.EQUIPMENT...
The KCLX radar will remain out of service for equipment upgrades
through June 11, and radar data will not be available during this
time. Neighboring radars include: Wilmington, NC (KLTX);
Jacksonville, FL (KJAX); Moody AFB, GA (KVAX); Warner Robins AFB, GA
(KJGX); and Columbia, SC (KCAE). Note that KJGX is currently down
though due to maintenance but should be back up no later than June 6.

Supplemental weather balloon releases at 18Z/06Z will continue
through at least the weekend in support of Tropical Cyclone
Cristobal forecasts.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Coastal Flood Advisory from 8 PM to 10 PM EDT this evening for
     SCZ048>050.
MARINE...None.

&&

$$
NEAR TERM...JRL
SHORT TERM...SPR
LONG TERM...DPB
AVIATION...JRL/SPR
MARINE...JRL/SPR
TIDES/COASTAL FLOODING...
EQUIPMENT...


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