Baltimore and the metro area will be under a heat advisory from noon until 8:00 this evening.

The National Weather Service says temperatures in the 90s combined with high humidity will make it feel like it's 105 to 109 degrees.

The heat wave will continue into the weekend with an excessive heat watch in effect from Saturday afternoon until the evening.  On Saturday, the heat index could top 109 degrees. 

From the National Weather Service:

Heat advisory remains in effect from noon today to 8 PM EDT this evening...

...Excessive heat watch remains in effect from Saturday afternoon through Saturday evening...

* heat index values...around 105 today and possibly greater than 110 Saturday.

* Temperatures...mid to upper 90s Friday and around 100 degrees Saturday.

* Impacts...risk of heat-related illness for those without air- conditioning or those outdoors for an extended period.

Precautionary/preparedness actions... A heat advisory means that a period of high temperatures is expected. The combination of high temperatures and high humidity will create a situation in which heat illnesses are possible. Take extra precautions if you work or spend time outside. When possible... reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear light weight and loose fitting clothing when possible and drink plenty of water. To reduce risk during outdoor work...the occupational safety and health administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency - call 911.

An excessive heat watch means that a prolonged period of dangerously high temperatures is possible. Prepare for extreme temperatures and high humidity which would create a situation in which heat illnesses are expected.