textproduct: Wilmington

WHAT HAS CHANGED

Heat advisory has been issued.

KEY MESSAGES

1) Hot and humid conditions this week.

DISCUSSION

KEY MESSAGE 1) Expansive mid level ridge will predominate through much of the week. This is leading to high confidence in hot and humid conditions prevailing across the area. Thus have gone ahead and issued a heat advisory through Thursday. This starts tomorrow, except for the Scioto Valley into northeast Kentucky where it starts Tuesday. The advisory may well have to go into Friday or even Saturday, but some uncertainty enters the picture as the ridge gets suppressed a bit south by then which introduces the potential for something beyond isolated convection. Have seen many times where extended periods of forecast hot weather get interrupted by an MCS that does not get depicted in guidance until late in the game. In addition, there is potential for parts of the area to exceed the heat index threshold of 105 that would necessitate a warning at some point during this heat wave. The problem is that small errors in forecast temperature and dew point can translate into larger errors in the heat index forecast. So have taken a more cautious approach by going with an advisory for an extended period of time. If/when confidence in heat indices exceeding that threshold, beyond isolated locations, increases then the advisory can be upgraded to a warning.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

MVFR ceilings across much of the area to start will lift to VFR early in the period with some places scattering. Spotty showers in central Ohio could briefly affect KCMH/KLCK before diminishing with the loss of heating. Clouds will decrease further after 00Z. With light winds and plenty of low level moisture, expect fog to start to develop. A deck of clouds with VFR ceilings will slowly shift eastward into the region after 06Z. This should stop further drops in visibility. But clouds are not expected to make it to KCMH/KLCK, so IFR visibilities are forecast there. Visibility will improve quickly after 12Z with a scattered cumulus deck as well as some higher clouds. Winds will remain light, eventually coming out of the south on Monday.

OUTLOOK...No significant weather expected.

ILN WATCHES/WARNINGS/ADVISORIES

OH...Heat Advisory from noon Monday to 8 PM EDT Thursday for OHZ026-034- 035-042>044-051>053-060>062-070>072-077>081. Heat Advisory from noon Tuesday to 8 PM EDT Thursday for OHZ045-046- 054>056-063>065-073-074-082-088. KY...Heat Advisory from noon Monday to 8 PM EDT Thursday for KYZ089>099. Heat Advisory from noon Tuesday to 8 PM EDT Thursday for KYZ100. IN...Heat Advisory from noon Monday to 8 PM EDT Thursday for INZ050-058- 059-066-073>075-080.