textproduct: NWS Wilmington

WHAT HAS CHANGED

Aviation discussion updated for 00Z TAFs

KEY MESSAGES

1) Building heat and humidity into the Weekend with Continued Rain Chances. Isolated Strong/Severe Storms Possible on Saturday and Sunday.

2) Prolonged Dangerous Heat Expected Next Week with Limited Rain Chances

DISCUSSION

KEY MESSAGE 1... Building heat and humidity into the Weekend with Continued Rain Chances. Isolated Strong/Severe Storms Possible on Saturday and Sunday.

Hotter and more humid on Saturday with temperatures in the lower to mid 90s. Sunday looks to be the hottest day, with temperatures topping out in the mid to upper 90s away from the coast. Dew points also increase after 24 hours of southerly moisture advection.

Heat Indices of 100-103 Saturday should remain just shy of the 105 F heat advisory threshold, (reflected in the latest forecast after tweaks to the NBM systematic biases). Sunday, however, indices could reach 105-108 F, with an advisory potentially needed for portions of the forecast area. Regardless, heat-related stress, illness, and impacts remain possible --- especially for anyone without effective cooling and/or adequate hydration.

Isolated to widely scattered convective activity/coverage Saturday should be less than today's, due to lack triggers, followed by more widespread storms Sunday as a surface front arrives into the area late in the day. Deep layer shear stays weak(10-15kts), but moderate to strong destabilization within an increasing moist, high PWAT airmass(2.0-2.1") both days may support locally damaging winds via precip loading and wet microburst processes.

KEY MESSAGE 2... Prolonged Dangerous Heat Expected Next Week with Limited Rain Chances

The weak sfc front is forecast to slip slowly south of the area, sometime during the day on Monday, though timing remains somewhat uncertain. In it's wake, sfc high pressure and associated NELY low- level flow may bring a brief reprieve from the heat, primary due to lower BL dewpoints in the upper 60s/near 70 and less oppressive humidity. Heat Indices could very well likely reach warning criteria(+110F) across portions of the area.

However, the onset of SELY low return flow leading and rising humidity, combined with a strong mid-level high (~597 dm) amplifying over the Tn Valley and mid South, will likely bring prolonged, dangerous heat through much of next week, centered on the July 4th holiday. Heat Indices could very well likely reach warning criteria(+110F) across portions of the area.

Compounding the heat are relatively low rain chances, with the bulk of NW flow convection currently expected to remain north of the area.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Storms continue to weaken this evening with VFR expected for most of the area. However, a line of weakening storms approaching LBT will affect the terminal between 00Z-01Z. Based on latest radar light to moderate SHRA seem more likely than TSRA, but the line continues to produce an occasional lightning strike. Remains of the line should clear LBT by 01Z. Other potential impact would be at MYR where convective debris may bring borderline MVFR conditions late evening through midnight.

Low level jet tonight of 25-30kt will curtail fog development, but could lead to brief development of MVFR ceilings, especially along the coast where boundary layer moisture is a little higher. Still, low level moisture is somewhat limited which will affect the extent of any ceilings that develop. Widespread VFR after sunrise Sat into midday before isolated convection may become a problem, mainly for coastal terminals. Coverage will be limited with ILM having best chances due to sea breeze collision in Brunswick county.

Extended Forecast...Ceiling and visibility restrictions possible in storms Saturday night and likely Sunday into Sunday night ahead of a cold front. Front lingers Monday with another round of storms. VFR Tuesday and Wednesday.

MARINE

The pressure gradient tightens Friday as high pressure offshore and low pressure inland support increasing southerly flow of 12 to 17 kts. Seas will gradually build to 2-3 ft Friday afternoon and 3-4 ft Friday night. Winds increase further Saturday and veer southwesterly as an area of low pressure traverses the Mid-Atlantic. Sustained winds of 17-20k ts with occasion gusting near 25 knots are expected, strongest INVOF of Surf City.

Southerly winds of 10-15 kts this afternoon as the Bermuda high pushes eastward. Seas of 2-3 feet will increase to 3-4 tonight and Saturday as flow becoming more SWLY with sustained wind of 15 to 20 kts(gusting to 25 knots at times) as an area of low pressure traverses the Mid-Atlantic. Recreational boaters should be cautious in area inlets on Saturday.

As the surface low shifts offshore Sunday, winds diminishes to 10-15 knots, while remaining generally southerly to southwesterly. Seas gradually subside to 2-3 ft out to 20 nm, but remain elevated at 3-4 ft out to 60 nm.

A back door cold front will drop southward through the region late Sunday into Monday. Northeasterly flow behind the front will peak around 15 knots on Monday afternoon. Seas respond by building to 3-4 feet in the nearshore waters, 4-5 feet in offshore NC waters.

ILM WATCHES/WARNINGS/ADVISORIES

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