textproduct: Newport/Morehead City

WHAT HAS CHANGED

Increased the chance of showers and thunderstorms for the rest of today across the northeast counties of ENC due to a weak low moving through. Winds were increased over land and marine areas along the track of the low as well.

KEY MESSAGES

1) Weak surface low to bring an increased risk of moderate to heavy rain and breezy conditions to northeastern ENC counties today.

2) Stalled front to lead to increasingly unsettled weather into this weekend.

3) Typical summertime pattern develops by next week with a daily thunderstorm risk and warming temperatures.

DISCUSSION

KEY MESSAGE 1...A well-defined, but compact, surface low is currently moving through the western Pamlico Sound vicinity. An area of moderate to heavy rain is accompanying this low, along with an increase in southerly winds along and just to the east of it. Southerly low-level steering flow will take this low north towards the Albemarle Sound vicinity by 5-8pm this evening. Along the track of the low, there will be a continued risk of moderate to heavy rain, a few lightning strikes, and breezy southerly winds. Given the trends with this low, I've increased the chance of rain along its track, and also bumped winds up. Based on obs from this morning, some areas just west of the track of the low could pick up a quick 0.25"-0.50" of rain.

KEY MESSAGE 2...A slow-moving frontal boundary is forecast to reach ENC sometime this evening or tonight. Of note, some guidance have trended even slower, suggesting the front may just barely get into ENC late tonight. Regardless, there is good model agreement regarding the front stalling over ENC through at least Saturday morning. A deep layer of moisture pooling along this front plus modest instability and increased low-level convergence should support scattered to numerous showers and thunderstorms off and on both day and night.

Deep layer shear beneath ridging aloft points towards a reduced risk of thunderstorm organization. At large, this should also lead to a reduced risk of severe thunderstorms. The one exception is during peak heating each day as steepening low- level lapse rates in a high PWAT airmass may support some water- loaded downdrafts capable of 40- 50 mph wind gusts and minor tree damage. This may especially be the case right along wherever the front sets up each day, as the area along the front will have the strongest convergence and "best" shear.

PWATs increasing to 1.75"-2.00" within a weakly-steered environment should support periods of heavy rain. The recent stretch of dry weather and ongoing drought should help to offset any hydro concerns. However, if heavy rain trains over any one area, especially urban areas, then a flooding risk could materialize.

KEY MESSAGE 3...Once this weekend's front lifts north, ENC will get back into a typical late-spring/early summer pattern characterized by moderate instability and weak to moderate deep layer shear. Convective initiation should primarily be seabreeze-driven. Given the expected shear/instability combo, there should be a daily risk of marginally severe thunderstorms, especially from Monday onwards. This potential is also supported by both machine learning and analog guidance.

Near-climo temperatures are expected during this time, with highs in the mid to upper 80s inland, and low to mid 80s along the coast. It should be noted that while the forecast will reflect an increased chance of showers and thunderstorms on Memorial Day, an all-day washout is not expected. It will be more unsettled than what we have seen the past few weeks, though.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

A weak area of low pressure will continue to lift north through northeastern sections of ENC this afternoon and early evening with an area of moderate to heavy rain and reduced VIS. This low will remain east of all ENC TAF sites, though. In the wake of the low, building cumulus clouds and isolated to scattered SHRA are expected, with at least a low risk (10-20% chance) of TSRA.

Later this evening and tonight, a slow-moving cold front will settle south into ENC. This should allow a continued chance of SCT SHRA and a low TSRA risk. Additionally, guidance suggests an increased risk of low CIGs along the front as well, with the lowest CIGs and greatest risk of LIFR conditions being focused north of the front. CIGs should rise some during the day Friday, but guidance may be too quick to improve conditions, especially with the front expected to stall over the area. Along and north of wherever the front stalls is where the greatest risk of IFR, or lower, conditions is expected.

Outlook: A stalled frontal boundary will support a continued risk of sub-VFR conditions and SHRA/TSRA into at least Saturday. From Sunday onwards, a more typical summertime pattern looks to develop with a daily risk of TSRA along the seabreeze.

MARINE

A weak area of low pressure will move through the Albemarle Sound vicinity over the next few hours with an increased risk of thunderstorms, and gusty south winds up to 20kt. In the wake of this low, typical summerlike conditions will prevail, with breezy thermal gradient winds, and seas of 3-5ft.

A cold front is forecast to slide slowly south into ENC tonight, with north or northeast winds developing behind it. Guidance suggests the front will stall around the central waters, with the northerly winds being focused primarily across the northern rivers/sounds/coastal waters. A weaker gradient along the front should keep the risk of 25kt winds lower for those waters. Along the front there will be a continued risk of thunderstorms.

Outlook: A cold front will remain stalled across the area through Saturday morning. The front will then shift north as a warm front Saturday afternoon, leaving behind a more typical summerlike pattern.

MHX WATCHES/WARNINGS/ADVISORIES

NC...None. MARINE...None.