Heat index values near 100 degrees are forecast for Northville and Novi on Wednesday, Sept. 2. The National Weather Service (NWS) issued a Heat Advisory for Oakland and Wayne counties, warning of dangerous conditions through 8 p.m.

The advisory covers seven Southeast Michigan counties: Lenawee, Livingston, Macomb, Monroe, Oakland, Washtenaw and Wayne. Afternoon temperatures are expected to climb into the low 90s. Combined with high humidity, the NWS said conditions will produce heat indices between 100 and 102 degrees in parts of the region.

Detroit's average September high is 74.4 degrees, according to the NWS. Wednesday's forecast runs nearly 20 degrees above that mark.

Overnight lows near 70 degrees are not expected to bring much relief from the humidity, according to the NWS.

The heat is only half the threat.

The NWS Storm Prediction Center also placed Southeast Michigan under a Slight Risk (level 2 of 5) for severe thunderstorms Wednesday afternoon and evening. CBS Detroit reported that storms could bring damaging winds, large hail, heavy rainfall, localized flooding and even an isolated tornado.

WDIV meteorologist Ashlee Baracy said the window for the strongest storms runs "roughly from 2 PM to midnight." Any strong thunderstorm could drop one to two inches of rain quickly, leading to localized flooding on roads and in poor-drainage areas, according to MLive's statewide forecast.

Nearby Plymouth-Canton schools dismissed the P-CEP campus early Wednesday because of the heat. No early dismissals for Northville Public Schools or Novi Community School District had been announced as of the morning of Sept. 2.

The regional transit authority SMART is offering free "Cooling Buses" at six Metro Detroit locations from 11 a.m. to 7 p.m. Tuesday and Wednesday, The Detroit News reported. The air-conditioned buses are open to anyone needing a place to cool down and stay hydrated. None of the six locations are in Northville or Novi.

More rain is possible Thursday and Friday, with a Marginal Risk (level 1 of 5) for severe storms Thursday, particularly along and south of I-96. Highs are expected to drop to the upper 70s for the Labor Day weekend.

Residents can check with Northville, Northville Township or Novi city offices for local cooling resources and sign up for weather alerts at weather.gov/dtx.