textproduct: NWS Wilmington

WHAT HAS CHANGED

Nudged high temperatures up a couple degrees as mostly clear skies are arriving sooner than originally expected. Otherwise, the forecast remains largely on track.

Aviation discussion updated for 12Z TAFs.

KEY MESSAGES

1) An early morning cold front will scour out moisture, leaving only a small chance of showers across parts of South Carolina today.

2) An unseasonably chilly Canadian airmass will bring temperatures 12-16 degrees below normal tonight through Wednesday night.

DISCUSSION

KEY MESSAGE 1: An early morning cold front will scour out moisture, leaving only a small chance of showers across parts of South Carolina today.

A cold front is moving south across the eastern Carolinas and should be pushing across the Santee River and toward Charleston by sunrise. The last of the showers across eastern South Carolina should push offshore between 6-8 AM and Canadian high pressure over the Great Lakes will begin to build southward. Although dry air will eventually work its way across the area today, there is a very slight chance of a pop-up shower this afternoon across Williamsburg and western Georgetown counties where a sliver of instability could still exist at the top of the daytime mixed layer.

KEY MESSAGE 2: An unseasonably chilly Canadian airmass will bring temperatures 12-16 degrees below normal tonight through Wednesday night.

A deep upper level trough will pivot across the Carolinas this evening and offshore overnight. Cold advection that begins today will intensify overnight as a deep stream of Canadian air is pulled south behind the upper trough. No matter what level you look at this is an unusual airmass for early June. 850 mb temps bottoming out in the +7C to +9C range and 700 mb temps falling to 0C to -2C are both a couple degrees below the 10th percentile climatological values for this time of year at KMHX.

Our forecast low for tonight is 52 in Wilmington. If this verifies it will tie the coldest June temperature in Wilmington this century when it reached 52 degrees on 6/5/2023.

Location Forecast Low Last Time This Cold in June Wilmington 52 6/5/2023 N Myrtle Beach 54 6/9/2017 Florence 51 6/1/2024 Lumberton 50 6/1/2024

Even in Lumberton, 50 degree or colder readings in June have only occurred twice this century so far.

The airmass should begin to modify Wednesday and Wednesday night's lows will be a few degrees warmer than tonight's, but still a good 10-12 degrees below normals for early June.

AVIATION /10Z TUESDAY THROUGH SATURDAY/

Expect improving conditions for the Myrtles early in the period as drier air arrives and low stratus moves offshore and/or erodes. Otherwise, expect VFR to continue where it is already present. Light shower activity is possible from midday through much of the afternoon at inland terminals beneath a 9000 ft, but no restrictions are expected due to these. Wind gusts can reach up to 20-25 knots today as Canadian high pressure builds in from the north. Wind gusts will diminish toward sunset, but steady winds for most or all of the night and dry air aloft will preclude any fog threat.

Extended Forecast...There is a low potential for early morning ground fog or low stratus clouds Thursday, Friday, and Saturday mornings, otherwise VFR.

MARINE

A cold front is pushing southward across the area as I write and should be south of Georgetown and Winyah Bay around sunrise. Northeasterly winds will increase throughout the day, reaching 20 to occasionally 25 kt today through Wednesday morning. The Small Craft Advisory will remain in effect for the winds and for seas anticipated to build to 4-6 feet inside 20 miles from shore, and to 7-9 feet over the 20-60 mile offshore waters.

Canadian high pressure over the Great Lakes today will build southeastward, finally reaching the East Coast on Thursday. Light winds will develop as the high reaches the area, then should turn more southerly for the weekend as the high drifts offshore.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement through this evening for NCZ106-108. SC...Beach Hazards Statement through this evening for SCZ054-056. MARINE...Small Craft Advisory until 2 AM EDT Thursday for AMZ250-252. Small Craft Advisory from 11 AM this morning to 2 AM EDT Thursday for AMZ254-256.