textproduct: NWS Wilmington

WHAT HAS CHANGED

As of 7am... Aviation discussion updated for 12Z TAFs.

As of 230am... Expected rainfall amounts have decreased, mainly for areas near and west of I-95. The Coastal Flood Advisory for the lower Cape Fear River has been allowed to expire. A new advisory will likely be needed for high tide tonight along the lower Cape Fear River.

KEY MESSAGES

1) Beneficial rain expected through through today.

2) The lower Cape Fear River will experience minor coastal with high tide again tonight.

3) Above normal temperatures by mid-week ahead of another cold front and rainfall chances Thursday.

DISCUSSION

KEY MESSAGE 1: Beneficial rain expected through today.

A stalled front well offshore will be drawn towards the coast today as multiple areas of low pressure track along it. These will bring an extended period of rain through most of the day, with rain tapering off from west to east during the mid-late afternoon and evening. Latest guidance trends have shifted the precip axis more eastward, leading to lesser precip amounts well inland and the highest amounts likely across southern and coastal sections of the area. A consolidated and deepening surface low will emerge and accelerate away from the northeastern NC coast on Saturday night, bringing an end to the precip as cooler and drier air filters in behind it.

A rather tight gradient in precip amounts should take shape generally along and northwest of I-95 given the front's position, with the greatest precip expected near the coast. Overall, expect between 0.50-0.75" near and west of I-95 with peak amounts near an inch possible while coastal areas should see between 0.75-1.25" with peak amounts around 1.50" possible, mainly across Georgetown into coastal Horry county. NBM forecast precip amounts overall are higher, suggesting 1-2" across most of the area with localized peak amounts up to 2.5", but this appears to be overdone as the component models from the HREF and the global ensembles depict generally 1- 1.5" less at various percentiles of each ensemble system.

Behind this system, a surge of cool and dry air will make for below normal temperatures between Saturday night and Sunday night. A gradual warming trend will commence thereafter before another front arrives with the next chance for rain around Wednesday or Thursday.

KEY MESSAGE 2: The Lower Cape Fear River will experience minor coastal with high tide again tonight.

Tide levels are expected to reach advisory levels along the Lower Cape Fear River, including downtown Wilmington generally from 10 PM to 1 AM tonight. TWL predictions suggest water levels will remain below thresholds with high tide late Sunday night.

KEY MESSAGE 3: Above normal temperatures by mid-week ahead of another cold front and rainfall chances Thursday.

Strong warm-air advection and May sunshine will lead to above normal temperatures by Wednesday. It is possible the NBM highs are a category too low, but much of that will depend on the amount of sunshine ultimately stymied by moisture advection/clouds. Otherwise, GFS ensembles and NBM suggest good chances of rainfall focused on Thursday at the moment as a strong cold front moves through the area supported by H5 trough over the Eastern U.S. At this time confidence is lacking regarding the timing of the front and how fast this system moves through, and subsequently QPF amounts. Given the drought, any rainfall would help some. Otherwise, a deeper drier/westerly column would suggest clearing by the end of the week with the potential for below normal temperatures again.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Light rain has overspread the terminals early this morning with transient vis reductions to MVFR. Current VFR cigs should fall to MVFR or IFR levels within the next 1-3 hours as an increasing number of observations to the west and southwest are showing low clouds approaching/developing. Steady rain should result in MVFR to occasionally IFR vis restrictions through a majority of today before clearing out during mid-late afternoon into early evening. VFR will return early in the nighttime hours as drier air filters in. Patchy MVFR mist cannot be ruled out as skies clear and winds slacken, but this carries low confidence as falling dew points should offset the fog potential soon after conditions become more favorable for its formation.

Extended Forecast...Predominantly VFR through Wednesday.

MARINE

Through tonight...A stalled front offshore will see multiple low pressure areas move along it today, bringing an extended period of rain with embedded thunder to the waters. The front is expected to stay far enough offshore to keep winds primarily northerly across the waters today, with speeds increasing to 15-20 kts this afternoon. Gusts as high as 25 kts are anticipated in the coastal waters southeast and east of Cape Fear, resulting in a Small Craft Advisory for those zones, while 25-30 kts should be observed in the 20-60nmi zones. Seas should stay mainly 2-4 ft in the coastal waters and 4-7 ft in the 20-60nmi waters, driven by a combination of northerly wind waves and northeasterly swells with a period around 9- 10 sec.

Sunday through Wednesday...Weaker offshore flow will prevail across the waters as high pressure prevails from WV to the Gulf Coast Sunday morning. The flow will veer as weak high pressure becomes established off the Carolinas by Sunday evening setting the stage for a weak Sly pressure gradient that will persist Monday through Tuesday. Potentially by late Wednesday the pressure gradient will finally tighten as another cold front pushes toward the area. GEFs 20 knot wind speed probabilities increase off suggesting some confidence in SC.Y for the waters by Wednesday night. The timing of this front is the main challenge with this part of the forecast. Regarding seas, the offshore flow will result in some range in seas early in the period, then seas mostly around 3 ft or less until the aforementioned pressure gradient tightens late in the period.

ILM WATCHES/WARNINGS/ADVISORIES

NC...Beach Hazards Statement through this evening for NCZ108. SC...Beach Hazards Statement through this evening for SCZ056. MARINE...Small Craft Advisory from 3 PM this afternoon to 11 PM EDT this evening for AMZ250-252.