textproduct: NWS Wilmington

WHAT HAS CHANGED

As of 800pm... Aviation discussion updated for 00Z. A cold front is crossing the area at this time with scattered showers along the front moving offshore over the next hour or two. Gusty north winds will take over behind the front and continue through tonight.

As of 241pm... Isolated strong thunderstorms accompanying the CFP could produce a 35 to 45 mph wind gust.

Updated 18Z aviation discussion.

KEY MESSAGES

1) Cold frontal passage, accompanied by a few thunderstorms, will occur late this afternoon or early this evening. A noticeable temperature change will follow later tonight.

2) Below normal temperatures Tuesday may bring a chance for frost on Tuesday night and Wednesday morning.

3) Above normal temperatures are expected ahead of a strong cold front on Friday. A few thunderstorms are also possible with the cold frontal passage, but confidence is low.

DISCUSSION

KEY MESSAGE 1: Cold frontal passage, accompanied by a few thunderstorms, will occur late this afternoon or early this evening. A noticeable temperature change will follow later tonight.

The warmth this afternoon may challenge a few of these record high temps.

Wilmington NC..........94 in 1907 Lumberton NC...........91 in 1907 N Myrtle Beach SC......85 in 2011 Florence SC............88 in 1995

Cold front dropping to the SE will struggle with available moisture to conjure up a few thunderstorms as it tracks across the forecast region later this afternoon thru this evening. With NW flow aloft, a scouring effect to occur due to this downslope trajectory. Still expect a few tstorms and with the possible interaction with the somewhat pinned sea breeze. Could potentially observe isolated 30 to 40+ mph wind gusts from any of these mature tstorms.

Skies partially clear out later this evening and overnight but the big picture will be the breezy and gusty N to NE winds in the wake of the cold FROPA. Strong high pressure will ridge across the area from the NE States resulting in the combined effects of a tightened sfc pg and CAA across the FA. The previous night time lows in the upper 50s to mid 60s will be replaced with low to mid 40s, OUCH!, come Tue morning along with that stiff NE breeze.

KEY MESSAGE 2: Below normal temperatures Tuesday may bring a chance for frost on Tuesday night and Wednesday morning.

High pressure will drift off of the Delmarva coastline Tuesday night into Wednesday morning. Cold air associated with the area of dry high pressure should allow much of the area to reach the upper 30s. The pressure gradient between high pressure to our north and the exiting cold front to our south will keep boundary layer winds elevated for all coastal areas and most of northeast SC. Temperatures should be around 40 degrees in these areas.

Divergent flow aloft and weak lift near the axis of an upper trough should produce some scattered to broken high clouds around midnight. This trough axis will also promote some stronger winds in the boundary layer through sunrise. These factors mean that frost is unlikely to develop. However, probabilities for temperatures below 37 degrees (rough estimate of maximum temperature for patchy frost) are around 10-20% for our inland counties. The 10th percentile minimum temperature for LBT is 37 degrees. Regardless, worst case scenario appears that this will be an isolated, low-impact frost event, if it occurs.

.KEY MESSAGE 3: Above normal temperatures are expected ahead of a strong cold front on Friday. A few thunderstorms are also possible with the cold frontal passage, but confidence is low.

Another strong cold front will approach the region late this week. A few thunderstorms are possible with the frontal passage, but confidence in this occurring is low at this time. While the timing of the front is the primary point of uncertainty, there are some questions regarding available instability. This is in part due to the existence of a broad upper level ridge over the southern US during the middle and late portions of this week. As this ridge degrades, a subsidence inversion over the Carolinas will provide just enough convective inhibition (along with dry air aloft) to hinder the production of instability. A conditionally favorable environment with very warm surface temperatures, dry air above the LFC, and respectable lapse rates could favor a strong storm or two, if any develop.

Ahead of the cold front, temperatures will soar into the mid and upper 80s inland. A few areas could approach record high temperatures. Coastal areas will peak in the mid and upper 70s behind a cooling sea breeze. The record high for Florence, SC on Friday, March 27th is 89 degrees, previously set in 2021. The record high temperature for Lumberton, NC for Friday, March 27th is 87 degrees, set in consecutive years: 1949 and 1950. Probabilities for tying or breaking these records currently sits at around 20%.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

VFR will prevail through the period as much drier air filters in tonight on gusty north winds. These gusty winds will continue into Tuesday morning before subsiding in the afternoon. As high pressure shifts to directly north of the area, expect winds to veer to between northeasterly in the afternoon as well.

Extended Forecast...There is a low chance of ground fog Thursday morning, otherwise VFR conditions should prevail through Friday. A cold front may bring restrictions due to low clouds and showers over Friday night into Saturday morning before a return to VFR occurs later in the day.

MARINE

Through Tonight...SCA already in effect for post cold frontal gusty NE winds.

Moderate southwest winds will continue ahead of the approaching cold front this afternoon. The CFP will occur from late this afternoon for the NC waters and early this evening for the SC Waters. After the FROPA, winds will veer to the N, then becoming gusty NE as the CAA surge combines with the tightened sfc pg as strong Canadian high pressure ridges in from the NE states. Strong SCA conditions will overspread the waters later this evening and overnight. Could observe a few Gale force 35 kt wind gusts but the frequency remains in question and therefore will continue to advertise the strong SCA. Seas will be a function of wind driven waves with 6 seconds or less periods. A decaying underlying 10 second period easterly swell will continue.

Tuesday Night through Friday... High pressure just off of the Delmarva coast will maintain northeast winds through Wednesday before moving eastward. Seas should hover around 3-5 feet. Onshore flow will become light late Wednesday and Thursday. Seas relax in the light and variable winds; around 2 feet. As onshore temperatures each afternoon, some enhancement is possible along the sea breeze. A stronger gradient becomes established on Thursday night ahead of a cold front. Southerly flow increases overnight into Friday.

ILM WATCHES/WARNINGS/ADVISORIES

NC...None. SC...None. MARINE...Small Craft Advisory until 2 AM EDT Wednesday for AMZ250-252- 254-256.