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000
FXUS62 KCHS 210149
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
949 PM EDT Sat Jul 20 2019

.SYNOPSIS...
The area will remain situated between an inland trough and
Atlantic high pressure into early next week. A cold front is
expected to stall over or close to the region by the middle of
next week, then linger into late week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Late Saturday evening: Isolated/scattered showers/thunderstorms
developing along mesoscale boundaries south of the Altamaha
River should spill into counties south of Interstate 16 before
dissipating by midnight or shortly thereafter.

Aside from adjusting PoPS to account for convection across far
southern counties, ongoing rain-free along/north of I-16 remain
generally on track for the remainder of the night. Low
temperatures will range from the lower to middle 70s inland to
around 80F near the coast.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday: Aloft, ridging will prevail for another day with the same
surface setup featuring a trough inland and high pressure to the
east. Model soundings look at least a little more conducive to
convection than they do for today (Saturday). We should be able to
get isolated showers and thunderstorms, but convection should remain
on the weaker end of the spectrum. Temperatures should rise into the
mid 90`s, with some locations pushing the upper 90`s. Heat index
values should top out around 105. Overnight, any lingering
convection should diminish during the evening and the rest of the
period should be dry. Lows are forecast for the low/mid 70`s inland
and the upper 70`s along the coast.

Monday: The upper ridge will weaken and start to be replaced by the
southern end of a longwave trough pushing into the eastern half of
the CONUS. Overall, the surface will Outflow from earlier convection could
cross the Altamaha River and produce a shower/thunderstorm this
evening. However, the prospects for measurable precipitation
appear meager, thus lowered inland PoPs to less than 15 percent
with no mention of showers. Otherwise, tranquil forecasts remain
on track and required no significant changes.

Mid-level ridging will persist through the night. At the
surface, our area will remain in between an inland trough and
Atlantic high pressure. PWATs are about 1.8", which is near
normal for this time of year. However, all of the synoptic
models and the CAMs are in great agreement showing a dry night.
This is due to strong mid-level capping and the lack of any
mesoscale lift. Other than some cumulus clouds early in the
evening, the overnight hours will be dry and mostly clear. Lows
should be in the 70s, which is near normal.remain unchanged
with the inland trough and subtropical high. A cold front will
begin to approach from the northwest late in the day, but
shouldn`t have any impact on the forecast for another 24 hours
or so. Convection should be similar to Sunday and the forecast
features rain chances in the 20-30 percent range, highest along
the southeast Georgia coast. Overnight, modestly better chance
of seeing some nocturnal showers, mainly across the coastal
waters. Instead of a dry forecast we have 20-30 percent chances
overnight.

Tuesday: The trough aloft will solidly encompass the eastern
seaboard and the front will finally push into Georgia and the
Carolinas. The first part of the day could end up being quiet before
convection develops upstream and drops into the forecast area later
in the day. Could even see some degree of a severe threat depending
on how organized convection can become. For now, the forecast
continue to feature rain chances in the 50-60 percent range. Will
have to see how cloud cover evolves and the impact on temperatures.
Currently we show mostly low 90`s, but this could be a bit underdone
if the bulk of the convection holds off until later in the day.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Likely POPs in order Tuesday night just ahead of the surface cold
front and mid level short wave. The front is forecast to stall along
the southeast coast during mid to late week. Broad upper troughing
will deliver a favorable medium for unsettled weather across the
forecast area during this period. Bouts of scattered to numerous
showers and tstms are expected Wednesday and perhaps again Thursday.
Model agreement on the frontal position wanes by late week with the
boundary tending to wash out by early next weekend. We maintained
POPs slightly greater than climo for this period. Temps will be
tempered by a good bit of cloud cover along with chances for
convective rains mid to late week.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR through Sunday. The chance for direct impacts from isolated
thunderstorms Sunday afternoon remains too low to justify any
mention within 00z TAFs.

Extended Aviation Outlook: Brief flight restrictions could occur
within thunderstorms, especially during the afternoon/evening hours
Sunday and Monday. The chance for thunderstorms/associated flight
restrictions are expected to increase Tuesday afternoon and evening
ahead of a cold front. Scattered to occasionally numerous showers
and tstms are expected in the vicinity of a stalled front during
mid/late week.

&&

.MARINE...
Overnight: Expect south to southwest winds to average 15-20
knots along with seas of 2-3 ft. A couple of thunderstorms
could push into GA marine zones through midnight, then the
remainder of the night should remain rain-free.

Sunday through Thursday: South to southwest flow will prevail
through Tuesday as the local waters sit between the inland trough
and high pressure to the east. Wind speeds will continue to be
enhanced at times, surging into the 15-20 knot range but should
remain below Small Craft Advisory levels. Seas should average 2-4
feet. Then for Tuesday night through Thursday, a cold front is
expected to stall out over or near the local waters mid to late
week. A weak gradient should result in light winds and seas in the 2
ft range. We also expect showers and tstms to increase in coverage
during this time frame.

&&

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

&&

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