National Weather Service Raw Text Product

142 
FXUS62 KCHS 170032
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
732 PM EST Sun Jan 16 2022

.SYNOPSIS...
Deepening low pressure will continue to move northeast and away
from the forecast area. Cold high pressure will build into the
region Monday and Tuesday, moving offshore Wednesday. A
reinforcing cold front will move through the area Thursday. A
coastal low pressure system could impact the area next weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Deep low pressure will track NE along the NC coast this evening
and mid-Atlantic tonight. As the low departs, WSW winds should
strengthen with gusts between 25-30 kts. These winds will remain
Wind Advisory criteria, the advisory will be cancelled with this
update. Early this evening, KCLX detected a few patches of weak
returns across Screven and Allendale Counties, likely 
associated with sprinkles or light rain. The sprinkles or light 
rain may continue for the next hour or two. Temperatures may 
slow cool early this evening, then cooling should increase after
midnight with the passage of wrap- around moisture/mid- level 
trough. Low temperatures are forecast to range in the lower to 
mid 30s inland to the upper 30s across the coastal counties.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Monday and Monday night: Aloft, another shortwave trough will swing 
through the Southern Appalachians and then push offshore into the 
evening. At the surface, the forecast area will start off the day 
within the large circulation around the still deepening low centered 
across PA and NY. By the afternoon, high pressure will draw closer 
as it moves into the Lower Mississippi Valley. The story of the day 
will be chilly temperatures paired with very gusty westerly winds. 
The tight pressure gradient around the parent low, pressure rises, 
and diurnal mixing will produce frequent wind gusts to around 30 mph 
across the entire area, with a few gusts up to around 35 mph 
possible. Temperatures will struggle into the low 50s in most areas, 
though locations across interior portions of the counties that 
border the Midlands might only top out in the upper 40s. With some 
persist low-level cloud cover and gusty winds, it will certainly 
feel much colder than what the actual temperature says. Winds will 
likely fall short of Wind Advisory criteria, but the Lake Wind 
Advisory for Lake Moultrie will remain in effect through the day. 
Overnight, the persistent gradient will keep winds elevated through 
the evening before relaxing late. Clear skies will prevail and lows 
are forecast to fall into the upper 20s everywhere away from the 
immediate coast. 

Tuesday through Wednesday: The flow aloft will transition from 
west-northwesterly, to zonal, then southwesterly by late Wednesday. 
At the surface, high pressure will slide across the area Tuesday, 
then offshore Wednesday. The forecast is dry, and winds will be 
considerably weaker. Tuesday highs are forecast for the low to mid 
50s, then low 60s by Wednesday. Tuesday night lows should range from 
around 30 inland, to around 40 at the coast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Beginning Wednesday night, a cold front will approach the area from 
the west and showers could begin spreading in late. The front is 
expected to shift across the forecast area Thursday and Thursday 
night and bring at least scattered showers across the entire area. 
Thursday highs are forecast to reach the low 60s in most areas.

From this point forward, the rest of the extended forecast is a bit 
of a mess. Both the GFS and ECMWF are displaying wild run to run 
inconsistencies regarding the potential for a coastal low and 
possible wintry precipitation for Friday and Friday night. In fact, 
the 12z runs of both models are now completely dry for the entire 
region by Friday afternoon. From there the discrepancies continue as 
the GFS depicts a significant coastal system with widespread 
precipitation Saturday night and Sunday, while the ECMWF is 
completely dry and keeps any potential system hundreds of miles 
further south. Balancing all this in the forecast grids is a 
challenge to say the least since the NBM still features significant 
rain chances coincident with periods of below freezing temperatures. 
Needless to say, forecast confidence in this period of the forecast 
is as close to zero as it can get.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Deep low pressure will track NE along the NC coast this evening
and mid-Atlantic tonight. As the low departs, WSW winds should
strengthen with gusts between 25-30 kts. A band of MVFR wrap-
around moisture may swing over the terminals between 4-8Z,
highlighted with a TEMPO group. Sky cover should decrease during
the pre-dawn hours, with SKC conditions expected on Monday. West
winds may strengthen slightly during the afternoon, winds 20-25
kts gusting to around 30 kts, then decreasing gradually during
the early evening.

Extended Aviation Outlook: VFR conditions will prevail through 
Wednesday. Gusty winds will occur Monday. Periodic flight 
restrictions possible Thursday and Thursday night as a cold 
front moves through.

&&

.MARINE...
Tonight: Dangerous marine conditions will continue through the
overnight period as a strong surface low pressure system moves
northward away from the forecast area. Gale force winds are
expected to prevail through tonight in all waters, including the
Charleston Harbor. Seas will remain quite elevated with 9 to 
13ft seas forecast. 

Monday through Friday: Strong westerly winds will continue across 
the local waters Monday thanks to a tight pressure gradient around 
the deepening low pressure centered to the north. Winds will 
gradually come down through the day, and the ongoing Gale Warnings 
will need to be replaced with Small Craft Advisories. Winds will 
drop off to around 5-10 knots Tuesday afternoon and Tuesday night 
before a modest increase and turning to be out of the south ahead of 
a front Wednesday night. The cold front will move off the coast 
Thursday night and high pressure will build in for Friday. This will 
bring a strong surge of northeast flow and a round of likely Small 
Craft Advisory conditions.

&&

.TIDES/COASTAL FLOODING...
Winds will shift to a strong offshore flow tonight, and this 
will lead to blowout tide conditions around the 1-2 am low tide.

High Surf: Local forecast tools show breakers as large as 5 to 
7 feet in the surf zone from late this morning into tonight. 
This has prompted a High Surf Advisory along coastal sections of
Charleston south to coastal Chatham County.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...High Surf Advisory until 1 AM EST Monday for GAZ119.
SC...Lake Wind Advisory until 6 PM EST Monday for SCZ045.
     High Surf Advisory until 1 AM EST Monday for SCZ048-051.
     High Surf Advisory until 4 AM EST Monday for SCZ049-050.
MARINE...Gale Warning until 1 PM EST Monday for AMZ352-374.
     Gale Warning until 4 PM EST Monday for AMZ350.
     Gale Warning until 10 AM EST Monday for AMZ354.
     Gale Warning until 4 AM EST Monday for AMZ330.

&&

$$

NEAR TERM...NED
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...NED
MARINE...BSH/CPM
TIDES/COASTAL FLOODING...