textproduct: Wilmington

WHAT HAS CHANGED

Heat headlines extended until Friday evening.

KEY MESSAGES

1) Extreme heat through Thursday, likely extending into Friday.

2) Hot and humid conditions will continue into the holiday weekend when the chance for showers and storms returns.

DISCUSSION

KEY MESSAGE 1)

Surface high pressure and upper level ridging remain anchored across the region through at least Thursday and possibly into Friday. Hot and humid conditions persist. Forecast highs in the lower to middle 90s, along with dew points in the middle to lower 70s, result in peak heat index values around the 105 mark with higher readings possible. An Extreme Heat Warning is in place through Friday to account for the high heat and humidity. Overnight lows in the 70s offer little relief from the heat.

According the latest model guidance, Friday may be just as hot as Thursday if convective activity does not occur. Very early CAM guidance suggests minimal storm activity through most of afternoon, although global guidance is still showing some greater chances for diurnal storms. Given the extent of the heat wave, the Extreme Heat Warning headlines have been extended to include Friday as well despite some uncertainty surrounding convection.

Despite most extreme heat subsiding Friday, this weekend will still feature hot and humid conditions.

KEY MESSAGE 2)

Ridging starts to break down on Friday and Saturday allowing chances for convection and less oppressive heat this weekend and into next week. Outdoor activities could see some impacts from isolated to scattered thunderstorm activity especially during the afternoon and evening hours. A microburst threat exists with any storms that form this weekend in the high instability, low shear, and high DCAPE environment. Locally heavy downpours can be expected in any of the slow moving storms.

AVIATION /00Z THURSDAY THROUGH MONDAY/

A big dome of high pressure over the region will continue to provide dry weather and hot temperatures. Few cumulus clouds that developed are dissipating, giving way to clear skies. Light winds, clear skies and high low level moisture will lead fog development again tonight. The fog will be most dense in river valleys. Have IFR conditions at KLUK and KILN with a tempo MVFR visibility restriction at KLCK. The fog will improve quickly Thursday morning with a return to VFR conditions.

Southwest winds at 5 kts or less overnight will increase to 8 to 10 kts Thursday afternoon.

OUTLOOK...Thunderstorms are possible Friday and into next week.

ILN WATCHES/WARNINGS/ADVISORIES

OH...Extreme Heat Warning until 8 PM EDT Friday for OHZ026-034-035- 042>046-051>056-060>065-070>074-077>082-088. KY...Extreme Heat Warning until 8 PM EDT Friday for KYZ089>100. IN...Extreme Heat Warning until 8 PM EDT Friday for INZ050-058-059-066- 073>075-080.