Marine Weather and Tide Forecast for McClellanville, SC

KEY MESSAGES
1) Dry forecast dominates through Friday, with temperatures nearing record highs each day.

2) Most significant cooldown of the season so far expected this weekend.

DISCUSSION
KEY MESSAGE 1...Dry forecast dominates through Friday, with temperatures nearing record highs each day.

Latest surface analysis shows an elongated surface high that stretches across the Gulf Coast States to offshore of the Carolinas. This surface ridge is associated with an upper- level ridge that's nearly overhead this afternoon. Widespread subsidence keeps the forecast dry through Friday.

500 mb heights hang around 592-594 dam, which easily rank in climatological maximums in this area, per SPC Sounding Climatology for KCHS, KMHX, and KHAT. This means very unseasonably warm temperatures that look a lot more like mid- to-late June than mid-October. Widespread highs in the upper 80s to near 90 inland and mid 80s at the coast expected through Friday. Record-tying or record-breaking high temperatures are in play here. Please see Climate section below for more info. Deep upper trough nudges upper ridge off the coast on Fri with lowering heights, but warm SW flow will prevail and should help to keep very warm temps.

KEY MESSAGE 2...Most significant cooldown of the season so far expected this weekend.

A strong cold front is still slated to move through the area Fri night into early Sat, ushering in the coolest air of autumn thus far. Latest guidance is trending drier again with best chance of shwrs as the cold front passes through early Sat morning and mainly coastal or off the coast and then again as deep upper trough swings through near noon-time. The best energy would be to the north of our area.

Deep northerly flow will develop as system shifts farther off the coast through Sat aftn. Dewpoints in the mid 60s to near 70 Fri evening will drop through Sat down into the 50s and even some 40s by late Sat. This drying trend will continue into Sat night with gusty northerly winds allowing dewpoints to bottom out early Sun in the 30s to around 40 close to the coast. Plenty of CAA will bring temps down quite a few degrees below normal Sat into Sun. Temps Sat aftn will resemble overnight temps just 12 hrs before, and the stiff northerly winds will make it feel even cooler. Expect overnight lows Sat night in the 40s inland to near 50 at the coast. Overall, fall-like weather will arrive Sat with a gradual warming through early next week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
High confidence in VFR through most of the TAF period.
Confidence a bit higher but overall remaining low for any sub- VFR ground fog, but decided to include in the TAFs for a few hours right around daybreak. Increasing moisture and winds will creep into the forecast toward the end of this TAF period but mainly in the way of some developing cu, a few mid to high clouds, and SW winds up to 10 kts heading into Fri aftn.

Extended Outlook...Northerly winds behind a cold front Friday night could gust over 30 knots into the day Saturday. Guidance suggesting low pressure will remain offshore and should keep any sub-VFR to the east away from TAF sites.

MARINE
Sub-SCA conditions continue through at least daytime Friday with sfc high pressure offshore. Pattern starts to change late Friday, as gradient winds increase ahead of a cold front. Front moves through very early Sat morning, allowing the winds to quickly veer from SW to the N, gradually veering even more to the NNE through the day Saturday into Sunday. Seas will ramp up in increasing winds ahead of the front through late Fri and will peak late Saturday into Sunday, ranging from 4-8 ft over the coastal waters out to 20 nm, to 8-13 ft over the offshore waters out 60 nm.

A Gale Watch has been issued for all of the local waters beginning Sat morning right around daybreak. Initially expect more in the way of Small Craft Advisory conditions with building seas and increasing winds, but expect solid Gale gusts and winds by Sat aftn. Should see gusts up to 35 to 40 kts late Sat through Sun with a strong pressure gradient persisting over the local waters between strong high pressure inland and low pressure well offshore.

CLIMATE
Current forecast vs. records: Thursday, October 15: - Wilmington, NC (KILM): 89F (88F in 1985)
- North Myrtle Beach, SC (KCRE): 84F (85F in 2008)
- Florence, SC (KFLO): 90F (89F in 2021 and 1985)
- Lumberton, NC (KLBT): 90F (91F in 1919)

Friday, October 16: - Wilmington, NC (KILM): 86F (87F in 2021, 2018, and 1975)
- North Myrtle Beach, SC (KCRE): 83F (88F in 1990)
- Florence, SC (KFLO): 88F (91F in 2021)
- Lumberton, NC (KLBT): 88F (92F in 1925)

ILM WATCHES/WARNINGS/ADVISORIES
NC...None.
SC...None.
MARINE...Gale Watch from Saturday morning through late Sunday night for AMZ250-252-254-256-280-284.