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687
FXUS62 KCHS 201131
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
731 AM EDT Mon May 20 2019

.SYNOPSIS...
High pressure will be the dominant weather feature this week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Shortly after daybreak: Weak daybreak moisture convergence
resulting in a few isolated showers from around Hilton Head
Island south over the GA waters. Stratus was inland with some
patchy fog adjacent to the CSRA and SC Midlands.

Today: Overall the warm and dry pattern looks to remain intact
with the mid level ridge axis forecast to only nudge a tad to
the east by an advancing but quickly weakening short wave. It
appears like it will remain too dry aloft along with poor mid
level instability, resulting in only spotty/isolated convective
rains along the SC sea breeze along and just inland from U.S. 17
in the mid afternoon afternoon hours. A narrow band of slightly
higher 850-500MB layer RH should push into our far northwest
zones late in the afternoon but with west winds in the boundary
layer and well mixed lower levels/unimpressive surface dew
points, only a few showers or isolated tstms seem possible in
this region late day. We have POPs slight chance ranges at best
today with a poor thermal updraft potential expected. Max temps
will be similar to Sunday, lower 90s inland to upper 80s in the
coastal corridor inland from the beaches and barrier islands.

Tonight: A few spotty showers are possible early in the evening
across SC zones and there is a slim chance the weak vort lobe
aloft and slightly deeper moisture could result in a few late
night showers across the Charleston Tri-County area as well. We
have POPs mainly silent post sunset, maintaining persistence
trends.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Tuesday: The mid/upper lvl ridge will temporarily weaken as a front
lingers just north of the area and subtle h5 shortwave activity
traverses the area. Other than a few showers and/or isolated
thunderstorm over the Tri-County area during peak heating, expect
most areas to be dry and warm. In general, highs should peak in the
low/mid 90s away from the coast. Temps should remain in the low/mid
80s near the coast. Overnight lows will be mild under little to no
clouds. In general, lows should range in the upper 60s inland to
around 70 closer to the coast.

Wednesday and Thursday: Sfc high pressure will become centered along
the Mid-Atlantic and Southeast coasts mid week while a large
mid/upper lvl ridge of high pressure remains centered over the
Southeast United States. Given the setup, warm and dry conditions
will likely prevail through mid week. In general, highs should warm
into the low/mid 90s inland while a more direct onshore wind limits
temps in the upper 80s to around 90 east of the I-95 corridor. Temps
should remain in the lower 80s along the immediate coast. Overnight
lows should range in the upper 60s to around 70 degrees.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Hot and dry conditions should prevail this weekend as deep layered
high pressure remains across the region. Friday afternoon temps
should top out in the mid/upper 90s away from the coast. However,
warmest conditions should occur late weekend into early next week as
the mid/upper lvl ridge makes a slight shift south, setting up a
northwest downslope flow across the region. This includes warmer
conditions along the beaches given the potential for a pinned
seabreeze each day. In general, Saturday and Sunday afternoon highs
should peak in the mid/upper 90s away from the coast and upper 80s
along/near the beaches. Temps could reach 100 degrees well inland
Saturday and Sunday, mainly along a corridor extending from
Allendale/Hampton Counties in Southeast South Carolina to Tattnall
County in Southeast Georgia. The combination of heat and sfc dewpts
mixing out to the low/mid 60s suggests heat index values around 100
degrees, mainly along and west of the I-95 corridor. Overnight lows
will likely be mild, generally in the low/mid 70s each night.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR through 12Z Tuesday. Isolated SHRA/TSRA may develop on the
sea breeze this afternoon, but this activity still looks too
spotty for any TAF considerations.

Extended Aviation Outlook: VFR conditions are expected at both CHS
and SAV terminals through late week.

&&

.MARINE...
Persistence forecast continues through tonight with south-
southwest flow mostly below 15 kt with seas 2 to 3 ft on average.
The land/sea interface will continue to see typical warm season
diurnal peaks during the afternoon and early evening hours, a
few gusts to 20 kt are possible as the sea breeze pushes inland
along the SC intra-coastal and adjacent Atlantic waters.

Tuesday through Saturday: High pressure will remain the dominant
weather feature across the coastal waters through late week,
supporting winds/seas that remain below Small Craft Advisory levels.
In general, south winds will prevail through Tuesday with wind
speeds no higher than 10-15 kts. By Wednesday, winds should become
more east/southeast around 15 kts or less, before returning to more
of a south/southwest flow late week. Seas should range between 1-3
ft.

&&

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

&&

$$
NEAR TERM...
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...
MARINE...