The National Weather Service is now forecasting extremely high temperatures for western Washington from Friday afternoon through Monday afternoon with temperatures possibly exceeding 100 degrees.

Here's their latest forecast:

URGENT - WEATHER MESSAGE National Weather Service Seattle WA

EXCESSIVE HEAT WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH MONDAY AFTERNOON...

* WHAT...Dangerously hot conditions with afternoon highs in the 90s and possibly near 100 Saturday and Sunday.

* WHERE...Portions of western Washington.

* WHEN...From Friday afternoon through Monday afternoon.

* IMPACTS...Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities.

* ADDITIONAL DETAILS...Overnight lows during this time frame will only cool off into the 60s and thus will not offer much in the way of cooling.

PRECAUTIONARY/PREPAREDNESS ACTIONS... Monitor the latest forecasts and warnings for updates on this situation. Be prepared to drink plenty of fluids, stay in an air- conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of minutes.