textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for 12Z TAFs.

KEY MESSAGES

1) Beneficial Rainfall expected Sunday into Monday.

DISCUSSION

KEY MESSAGE 1...Beneficial Rainfall expected Sunday into Monday.

A southern stream system emerging from the Southwest Sat morning works its way across the southern half of the country Sat into Sun. Weak ridging ahead of this system will lead to a prolonged period of deep northwest flow, keeping deep dry air over the local area. Precipitable water starts to increase Sat night, but much of this increase is above 500mb and below 850mb, the mid-levels remain dry until daybreak Sun when deep moisture return sets up. Precipitable water exceeds the 90th percentile by mid-morning Sun, eventually approaching or even exceeding the max Sun afternoon into Sun night. At the same time heights start to fall as the southern stream shortwave/low moves east. Increasing instability and enhanced divergence aloft should lead to a period of healthy rain developing over the area by mid-morning Sun and lasting into Sun night. Not expecting moderate to heavy rain all day and night, but there is certainly potential for periods of it.

Track of the surface low Sun into Mon is over or just north of the area, limiting strong to severe potential although not ruling it out. There is a layer of 40-45 kt wind around 5k ft Sun afternoon which could mix to the surface, especially with any heavier rain. Again, potential is very low, but is there. Thunder seems possible during the afternoon Sun based on latest forecast soundings, but wouldn't be widespread. Total rainfall looks to be on the order of an inch or so across the area with the typical locally higher caveat associated with embedded convection.

AVIATION /12Z THURSDAY THROUGH MONDAY/

High confidence exists for VFR to prevail through the TAF period as cool and dry high pressure builds in from the west, maintaining a steady north wind through the daylight hours today. With the pressure gradient becoming weak late in the day, expect winds to become light or calm during the evening. Another surge of dry air will result in north winds picking up again later in the night, with both the abundant dry air and expected increase in winds precluding any threat for mist/fog.

Extended Forecast...VFR conditions dominate Thursday night through Saturday with high pressure prevailing. Flight restrictions possible later Saturday night into Monday as a low pressure system affects the area.

MARINE

Through Tonight... As high pressure builds in from the west, expect breezy north winds at 15-20 kts over the waters through this morning. As the pressure gradient weakens during the afternoon, expect a corresponding decrease in winds to 10 kts or less with this continuing into the night. Another surge of dry air will result in north winds picking up again later in the night to around 10-15 kts. Seas around 2-4 ft through this morning will decrease to around 1-2 ft this afternoon as winds relax, then rebound slightly to 1-3 ft late tonight as winds pick up. Lingering SSW swells of 1-3 ft with a period of 6-7 sec will gradually lose influence through this morning while northerly wind waves of 1-3 ft take over.

Friday through Monday... Northerly flow decreases Fri as high pressure settles south, then shifts offshore Sat. Weak gradient through the end of the week will keep speeds 10 kt or less Fri night and Sat. Early next week gradient starts becoming more defined as low pressure moves across the Deep South Sun into Mon and then offshore Mon. Prolonged period of enhanced southerly flow will build seas over 6 ft by midday Sun and is likely to keep seas in excess of 6 ft through Mon. Headline are all but guaranteed for the start of next week.

ILM WATCHES/WARNINGS/ADVISORIES

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