textproduct: NWS Wilmington

WHAT HAS CHANGED

Discussions updated. Aviation discussion updated for 0z TAFs.

KEY MESSAGES

1) Elevated rain chances continue through Thursday, with rain chances closer to seasonal norms from Friday through early next week.

2) Increasing heat and humidity is expected next week which could result in afternoon heat indices nearing 105F.

DISCUSSION

KEY MESSAGE 1... Elevated rain chances continue through Thursday, with rain chances closer to seasonal norms from Friday through early next week.

Similar to the last couple nights, another round of showers and isolated storms is expected to develop late in the night and affect coastal areas mainly on Thursday morning. As high-level debris clouds spread west, this will limit heating for inland areas in the morning. However, after morning cloud cover thins out, a separate area of showers and storms is expected to develop inland from the coast during the afternoon as the air heats up. Very heavy rain remains the primary concern as precipitable water values around 2- 2.2" continue to stream across the area. Although southerly low to mid-level flow of 10-20 kts should keep most of the showers and storms moving, if an outflow boundary happens to push out of a storm towards the south, isolated flash flooding may occur due to heavy rain persisting over the same area.

From Friday onward, the upper disturbance that has remained in place over the last few days should be a shadow of its former self with a remnant weakness in the height field between the large upper high centered near the Four Corners and another near Bermuda. This weakness in the height field on the periphery of the offshore high will result in a more typical summertime pattern with isolated pop- up showers and storms from Friday through Sunday. With that said, considerable dry air is depicted in forecast soundings on Friday and Saturday before another plume of moisture lifts northward on Sunday. Thus, expect activity to be more spotty and short-lived on Friday and Saturday with somewhat greater coverage on Sunday.

Although the greater moisture remains in place into next week, the ridge is expected to build westward, introducing some subsidence into the picture, likely keeping coverage in the typical summertime isolated to widely scattered realm.

KEY MESSAGE 2... Increasing heat and humidity is expected early next week which could result in afternoon heat indices nearing 105F.

As ridging over the Atlantic builds westward in tandem with a persistent moisture plume, expect both temperatures and dew points to rise above normal. With highs reaching the mid 90s and dew points in the low-mid 70s, afternoon heat index values should peak above 100F across parts of the area by Monday and potentially reach 105F in some areas by midweek. Temperatures and dew points will be refined in future forecasts.

AVIATION /00Z THURSDAY THROUGH MONDAY/

VFR with clear skies through this evening. Good chance for fog development across inland terminals overnight and early Thursday morning as winds go calm and low-levels remain moist. Best chance for IFR, and potentially LIFR, conditions is across inland NE SC (including KFLO), although sub-MVFR conditions are also possible for inland SE NC. Lingering winds and scattered showers early in the morning should keep coastal terminals fog- free. After any fog dissipates Thursday morning, VFR will prevail during the day with scattered diurnal cu around 4-6 kft. Have included PROB30s for KFLO and KLBT for potential afternoon thunderstorms tomorrow.

Extended Forecast... Transient restrictions are possible in showers and storms mainly during the afternoon each day through the period. The moist low-level airmass will also support a greater potential for morning fog or stratus each day.

MARINE

Tonight through Sunday... Bermuda high pressure will maintain a generally southerly wind between 5-15 kts across the waters through Sunday. Seas generally hold in the 2-3 ft range with a period of 4 ft seas affecting the 20-60nmi zone between Friday midday through Saturday afternoon. A persistent southeasterly swell is expected to be the primary contributor to the wave spectrum with a period around 7-8 sec.

ILM WATCHES/WARNINGS/ADVISORIES

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