Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 240834 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 334 AM EST Tue Jan 24 2017 .SYNOPSIS...
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High pressure will build into the area today and tonight, then prevail through Wednesday. A cold front will push through Thursday followed by cooler high pressure into the weekend. Another cold front could drop into the area early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Today: Surface low pressure south of Long Island in tandem with it`s mid level low near the Delmarva will move further NE, as both features reach SE of Long Island by 00Z Wednesday. Mid level heights will climb, and with plentiful sunshine and 850 mb temps moderating to 10-12C, we look for a warmer day than yesterday. Highs will generally top out in the mid and upper 60s, or about 6-9F above normal for late January. Gusty W-NW breezes will be common given steady isallobaric pressure rises along with deep mixing. Winds on average will be 10-20 mph until around sunset. Tonight: High pressure centered over southern FL will poke north atop the local region, as mid level ridging also builds overhead. A decoupling of winds and the dry air mass, along with clear skies will translate to excellent radiational cooling. It`ll wind up be the coolest night in about 2 weeks, with min temps as low as 40-45F most places inland from US-17, with even some upper 30s. Barrier island communities will be in the upper 40s.
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&& .SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
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Surface high pressure will prevail on Wednesday providing quiet and dry conditions. Expect sunny skies through much of the day, then an increase in cloud cover overnight as a cold front approaches from the west. The cold front will enter the forecast area Thursday morning and then quickly push offshore by midday. Some showers are expected to accompany the front, but overall rainfall totals will be fairly light, generally a tenth of an inch or less. Behind the front on Thursday, winds could get a bit breezy with gusts around 25 mph in the afternoon. Cool and dry high pressure will then return for Friday. Temperatures above normal early in the period will finally become more seasonable, even cooler than normal, by Friday with cold advection behind the front.
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&& .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
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Cool and dry high pressure will persist through much of the period. A reinforcing cold front could drop into the area early next week. The highlight of the long term period will be the return to cooler, more seasonable temperatures. The dry air mass in place will preclude any precipitation chances.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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VFR through 06Z Wednesday. A tight gradient and cold advection prior to daybreak, then deeper mixing during the daylight hours will lead to gusty W-NW winds at both terminals. Winds will then diminish quickly around sunset. Extended Aviation Outlook: Brief flight restrictions possible early Thursday with a cold front. Otherwise, VFR. Gusty conditions likely Thursday through Saturday, mainly in the afternoon.
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&& .MARINE...
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Today: Deep low pressure south of Long Island will continue to track further NE, with its large and associated cyclonic flow to extend across the waters this morning. That along with cool advection, a tight gradient and pressure rises around 1-2 mb every 3 hours, will support a Gale Warning on the outer GA waters and a SCA elsewhere. Conditions will improve this afternoon as cool advection has ended and the gradient starts to slacken. Tonight: High pressure builds from the S and SW, as the gradient eases further. On average winds will be less than about 15 kt and seas with the offshore trajectories will be no more than 3 or 4 ft early...subsiding a foot overnight. Wednesday through Sunday: Winds/seas will begin to increase Wednesday ahead of an approaching cold front. Small Craft Advisories will be likely for at least the nearshore Charleston county waters and the outer GA waters by late Wednesday night/early Thursday. The front will cross the waters midday Thursday with elevated winds to persist in its wake. Conditions may briefly improve on Friday, however additional periods of Small Craft Advisory conditions are possible through the weekend.
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&& .CHS WATCHES/WARNINGS/ADVISORIES...
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GA...None. SC...None. MARINE...Small Craft Advisory until 10 AM EST this morning for AMZ330- 352-354. Small Craft Advisory until 1 PM EST this afternoon for AMZ350. Gale Warning until 7 AM EST this morning for AMZ374.
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&& $$ NEAR TERM... SHORT TERM...ECT LONG TERM...ECT AVIATION... MARINE...

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