textproduct: NWS Wilmington

WHAT HAS CHANGED

PoPs have been updated based on the latest HRRR and WOFS ensembles for convection over the next few hours. It may take until 10-11 pm for the last showers to exit the South Carolina coastline where up to 2000 J/kg of elevated CAPE remains in place above the rain-cooled surface.

KEY MESSAGES

1) Deep tropical moisture will maintain a low potential for excessive rainfall through Thursday.

DISCUSSION

KEY MESSAGE 1... Deep tropical moisture will maintain a low potential for excessive rainfall through Thursday.

Isolated to scattered showers and storms still expected this aftn and evening in association with the sea breeze and interaction of convective outflows. Severe weather is not anticipated, but there is a low risk of minor flooding if storms train over the same area.

For much of Thu the air mass remains unchanged with an abundance of deep moisture, although precipitable water is down a bit compared to earlier in the week. Initially forcing is weak with limited low-level convergence and pockets of surface-based instability under flow aloft that is weakly divergent bordering on being convergent. The lackluster environment will keep storm coverage limited into Thu afternoon, likely scattered sea breeze action, until a cold front moves in from the north. The front has the potential to kick off more widespread showers and thunderstorms given the environment it is moving into. Exact timing of the front is still in question, but nearly all of the guidance insists the front will push south of the area sometime Thu night into Fri. Heavy rain will be possible in any convection that develops along the front with potential for significant rainfall amounts. However, flooding is not a concern at the moment.

AVIATION /00Z THURSDAY THROUGH MONDAY/

Showers continue to redevelop across portions of eastern South Carolina this evening and may continue through 03z before moving off the coast. Although ceilings should remain VFR, there is a low potential for MVFR visibility in rain and possible thunderstorms at KMYR and KCRE over the next couple of hours. VFR conditions are anticipated to prevail through most of the night up until 09-11z when there is a moderate potential for MVFR stratocumulus to develop near the coast affecting all the coastal airports.

Once any morning low clouds burn through, attention will shift to a cold front moving southward into the area. The front should make it through KLBT during the early afternoon, but the collision of the front and the seabreeze boundary during the mid to late afternoon could lead to scattered thunderstorms developing. The highest potential for impacts is at KILM, with moderate potential for impacts at KCRE and KMYR. KFLO has a lower potential for late afternoon showers as the front arrives there.

Extended Forecast...The threat for late-night low stratus or fog will continue through much of this week at KFLO and KLBT. After a brief lull in convective potential Friday, the arrival of a second cold front could bring more rain chances Saturday.

MARINE

Through Thursday... Moderate to fresh breeze out of the southwest continues through this evening. Pressure gradient tightens slightly tonight, which may allow gusts to escalate over 25 kts at times during the overnight hours for the coastal waters from Surf City, NC to Cape Fear, NC out 20 nm. However, it does not appear consistent enough to issue a Small Craft Advisory at this time. Winds may gust up to 30 kts at times over the offshore waters out 60 nm from Surf City. This gradient finally relaxes late Thursday morning, and winds shift slightly to the WSW. Seas at 2-4 ft along the coastal waters out 20 nm, which may bump up to 3-5 ft during the gradient increase tonight. Seas at 4-5 ft over the offshore waters out 60 nm, with a bump up to 4-6 ft during the gradient increase. Outside of wind waves, look for a primary southeasterly swell at 8-9 seconds.

Thursday night through Sunday... A cold front will push south across the waters Thu night into Fri with winds veering from southwest to northeast. Northerly surge Thu night into Fri will briefly increase winds and seas, but conditions will remain below SCA thresholds. The front stalls in the area Fri, likely just to the south, before returning back north Sat. The result will be variable winds with speeds around 10 kt as the pressure gradient remains weak. A second front pushes south Sat night into Sun, setting up another northerly surge for Sun with winds up to 15-20 kt.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement until 8 PM EDT this evening for NCZ106- 108. SC...Beach Hazards Statement until 8 PM EDT this evening for SCZ054- 056. MARINE...None.