textproduct: NWS Wilmington

WHAT HAS CHANGED

A Small Craft Advisory was issued for Tuesday and Wednesday. Updated aviation discussion.

KEY MESSAGES

1) Hot weather continues through the first half of this week with additional Heat Advisories possible.

2) Best chances for rain arrive with a strong cold front during mid to late week, including a risk for strong thunderstorms and flash flooding.

3) A period of enhanced winds and seas will exist through midweek as a stronger cold front drops down from the north.

DISCUSSION

KEY MESSAGE 1...Hot weather continues through Wednesday with additional Heat Advisories possible.

The region will remain sandwiched between mid-upper troughing to the north and the closed mid-upper low associated with T.D Two to the south, leaving a weak ridge axis in between. Temperatures in the low- mid troposphere are forecast to hold at similar levels to those observed over the weekend, supporting continued above-normal temperatures and heat indices breaching 100F. The extent of cloudiness and showers/storms will affect whether some areas reach heat indices of 105F, but it appears additional Heat Advisories are possible until the next front comes down mid to late week. Until then, coverage of showers/storms should remain isolated through Wednesday.

KEY MESSAGE 2...Best chances for rain arrive with a strong cold front during mid to late week, including a risk for strong thunderstorms and flash flooding.

The stalled front will continue to lift back to the north leaving the threat of isolated to widely scattered pop-up showers and storms through Wed. Any stronger storms will mainly remain north of the local area as the front lifts north, with the focus of any convection along the sea breeze and any convergence zones that happen to form inland. An isolated strong to damaging wind gust cannot be ruled out if a storm can take advantage of the steep low-level lapse rates combined with a heavy, water-loaded downdraft. Something to watch is the progression of showers and storms to the north, which could send outflow into our northern tier of counties (Pender through Marlboro) and produce areas of heavy showers and storms through late day. Tuesday is looking drier with only isolated convection at the most.

As troughing becomes reinforced over the eastern CONUS during midweek, a stronger cold front is progged to push southward during the Wednesday/Thursday timeframe. While guidance tools have slowed down the frontal progression and suggest Wednesday will be another hot and mostly dry day with isolated pop-up showers and storms, the incoming front is likely to enhance precip coverage into the scattered to numerous realm when it does arrive, which could be over Wednesday night into Thursday.

How far south this front reaches before stalling, and when this occurs, still carries low confidence as guidance tools remain mixed with respect to its position, so this will need to be monitored as shower and storm coverage could be enhanced through the remainder of the week and into the weekend if the front is stalled along the coast as opposed to further offshore over the Gulf Stream.

In addition, this front is expected to bring a risk for isolated thunderstorms with strong to locally damaging wind gusts as wind shear increases to 15-25 kts on Wednesday and Thursday. Perhaps the more notable threat is for flash flooding from heavy storms backbuilding and/or tracking over the same area multiple times. The flash flooding threat will persist if the front stalls along or just inland of the coast.

KEY MESSAGE 3...A period of enhanced winds and seas will exist through midweek as a stronger cold front drops down from the north.

See marine discussion below.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Scattered cu will remain through the early evening with mainly isolated storms around. The chance for storms will be greatest at KLBT where some flight restrictions are possible. May see a brief storm along the sea breeze boundary at KCRE/KMYR but coverage/confidence too low to include at this point. The sea breeze will also allow winds to increase and become gusty at times at the coastal terminals.

Extended Forecast...Low potential for MVFR/IFR from storms Tuesday, mainly due to limited storm coverage. The areal extent of storms is expected to gradually increase from Wednesday night onward as cold front drops south. This will result in an increasing potential for MVFR/IFR conditions at times.

MARINE

Monday night through Saturday...Steady south to southwest winds are expected through midweek with daily enhancements nearshore due to the sea breeze. An approaching cold front will help tighten the pressure gradient from Tuesday afternoon into Wednesday night, resulting in the issuance of a Small Craft Advisory with winds and seas firmly above criteria. Winds diminish overnight Wednesday into Thursday as a cold front drifts in from the north and stalls near or over the waters, resulting in low confidence regarding the wind direction on Friday pending the location of the front.

Seas down around 2 to 4 ft will rise to 4 to 6 ft by late Tuesday, remaining through late Wednesday. Seas will diminish to 2 to 4 ft through Thursday as winds weaken. Marine conditions should remain below any thresholds with lower winds and seas as cold front remains in vicinity.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Heat Advisory until 7 PM EDT this evening for NCZ087-096-099- 105>110. Beach Hazards Statement until 8 PM EDT this evening for NCZ106- 108. SC...Heat Advisory until 7 PM EDT this evening for SCZ017-023-024- 033-054-058-059. Beach Hazards Statement until 8 PM EDT this evening for SCZ054- 056. MARINE...Small Craft Advisory from 11 AM Tuesday to 10 PM EDT Wednesday for AMZ250-252-254-256.