Marine Weather and Tide Forecast for Conway, SC

NEAR TERM /THROUGH TONIGHT/
Confidence increasing as model guidance comes together showing snow for the area tonight. Snow amounts should be between 1 to 3 inches with greatest totals right along the Cape Fear coast. A Winter Storm Warning is now in effect from 9p to 8a for the eastern portion of the forecast area for amounts up to 3 inches and Winter Weather Advisory for remaining portion of the area for up to an inch. Expect some locally higher amounts.

A Cold Weather Advisory is in effect until 10 am this morning as cold temps and northerly winds combine to produce wind chills 15 or below, especially between 6 and 10a this morning. Will most likely need another Advisory when this ends for tonight.

Initially, clouds will thicken through the day and expect spotty rain or snow possible late aftn, but once the column moisture increases and ice formation is possible in the upper levels, then expect a fairly steady snow to begin into Tues evening as winds aloft increase with increasing isentropic lift. The mid to upper trough will dig south as it progresses eastward into Tues night. As the same time, Arctic high will continue to build into the area with increasing northerly flow of dry and cold air. The warm and moist air will run over this dense cold air in place with increasing isentropic lift overnight Tue. Looking at the H85 to H7 winds, could see SW winds up to 40 to 60 kts along with a decent jet streak which should produce some increased forcing and lift and could produce some banding across the area. Another factor will be the SLR with values closer to 10 at the coast, but perhaps up to 14 inland. And, lastly, there is some potential for sleet to mix in along the coast as a minimal warm nose shows on the soundings. Therefore, could see an adjustment to the warning area needed as we fine tune the snow amounts later today.

The GFS continues to show best lift to the south and offshore, but the ECMWF and CMC show greater values stretched up along the coast.
The best lift and greatest snow should fall beginning late evening and ending before daybreak. This should be enough produce a fairly widespread snowfall across the area overnight tonight with greatest amounts right along the coast, looking to be from 1 to 3 inches with locally higher amounts most likely north of Cape Fear. The snow should taper off into early Wed morning as best lift and moisture shifts eastward.

Although high temps will reach into the mid 30s most places, the stiff northerly winds will make it feel in the teens this morning and near or below freezing this afternoon for wind chills. Temps tonight will once again be well below normal with reading in the low 20s most places and wind chills in the teens.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
Partly to mostly cloudy skies around daybreak Wed will clear west to east during the morning as mid and high cloud shift east. Forecast soundings show very dry air moving in, even reaching the coast, prior to 12Z. The layer from 2k ft to 16k ft has a large amount of air with RH under 10%, suggesting any precipitation will come to an end prior to 12Z and before the start of the short term. Even though skies will clear out for the afternoon a very cold air mass will be in place. Depending on the amount of snow cover it is conceivable many areas will struggle to rise above freezing.

Although winds will be light Wed night, it won't take much if any wind to lead to apparent temperatures under 15 degrees Wed night and another cold weather advisory seems likely. In fact, if there is snow around Wed night lows could end up several degrees low than forecast. Given light to calm winds forecast and the potential for snow lows in the low single digits to around 0 for the extreme cold spots (looking at you Holly Shelter and northwest Pender County)
could be possible.

Still a lot of uncertainty surrounding Thu. Weak coastal trough develops Wed night into Thu with hints of some light overrunning drizzle/rain developing as low pressure consolidates well offshore. The isentropic lift is weak but there is still enough moisture below 700mb to support light precipitation. The key will be is the low close enough to the coast for rain to fall over land. Any rain that falls during the morning hours will be in the form of freezing rain. The vertical profiles show a decent warm nose around 900 mb during the morning hours. The warm nose remains a fixture during the day with weak warm advection helping to raise surface temps above freezing by midday. Low level dry air starts to work its way in after 21Z so there may not be much precipitation around after that. However, temperatures will tumble in the evening and if there is still any rain or drizzle it would transition to freezing rain/drizzle before ending around 03Z.

LONG TERM /FRIDAY THROUGH MONDAY/
Broad mid-level troughing over the eastern CONUS Fri shifts offshore for the weekend, leaving flat/zonal flow in place through the weekend. The progressive pattern leads to faster movement of surface features. High pressure following a weak/dry cold front later Fri moves overhead Sat and the offshore Sun. Not much cold advection in the post front regime on Sat and the development of return flow Sun and Mon will lead to a round of warm advection. Temperatures below climo Fri and Sat return near to above climo Sun and Mon. Mid-level pattern does start to amplify on Mon with the flow aloft becoming weakly divergent. Increasing moisture and steepening mid-level lapse rates later Mon would support at least scattered showers in the area Mon.

AVIATION /08Z TUESDAY THROUGH SATURDAY/
VFR conditions are expected initially with mainly MVFR and possibly brief IFR in mainly snow after 22z. Some sleet may affect the coastal terminals of mainly CRE and MYR briefly, especially between 22z and 01z. Expect ceilings to lower to MVFR between 19z and 21z. Vsbys should be MVFR after 22z in light snow and possibly down to IFR between 02z and 08z in light snow.
The bulk of snow should hold off til aft 00Z Wed. Winds will remain out of the N around 10 to 15 kts with a bit of an increase and gusts after 02z Wed.

Extended Outlook...Back to VFR Wednesday afternoon. Another system could cause flight restrictions on Thursday into Friday.

MARINE
Through Tonight....
Northerly flow up to 15 to 20 kts this morning will increase up to 20 to 25 kts into tonight as Arctic high pressure continues to build into the area. Wind gusts could run up to 30 kts overnight. A passing storm system over the offshore waters will produce increased winds, seas and some snow and wintry weather overnight. Seas will increase from 3 to 4 ft this morning up to 4 to 6 ft tonight. A Small Craft Advisory will be in effect this evening through Wed morning.

Wednesday through Saturday...
Northerly winds expected Wed into Sat with strongest winds expected Wed and Wed night as weak coastal trough sets up.
Gradient will start to relax Thu into Fri, even though a dry cold front moves across the waters Fri into Sat. The front lacks strong cold advection and the increase in surface pressure gradient is minimal. Surface high builds in from the west following the late week front with the center of the high shifting over the waters later Sat. Light and variable winds set up by midday Sat and continue through Sat night. Seas will gradually subside through the end of the week, following the decreasing trend in wind speeds. Small Craft Advisory seas are likely to persist into Wed afternoon before the slow but steady decrease in speeds allows seas to drop under 6ft. Seas 2-4 ft Thu drop to 2-3 ft Fri and closer to 2 ft Sat. Seas will be a mix of a northerly wind wave and an easterly swell.

ILM WATCHES/WARNINGS/ADVISORIES
NC...Cold Weather Advisory until 10 AM EST this morning for NCZ087- 096-099-105>110.
Winter Weather Advisory from 9 PM this evening to 8 AM EST Wednesday for NCZ087-096.
Winter Storm Warning from 9 PM this evening to 8 AM EST Wednesday for NCZ099-105>110.
SC...Cold Weather Advisory until 10 AM EST this morning for SCZ017- 023-024-032-033-039-054>056-058-059.
Winter Weather Advisory from 9 PM this evening to 8 AM EST Wednesday for SCZ017-023-024-032-033.
Winter Storm Warning from 9 PM this evening to 8 AM EST Wednesday for SCZ039-054>056-058-059.
MARINE...Small Craft Advisory from 9 PM this evening to 2 PM EST Wednesday for AMZ250-252-254-256.