Severe

* WHAT...Dangerously hot conditions with high temperatures in the upper 90s to 105. Nights will be very warm with low temperatures in the mid 60s to mid 70s. * WHERE...San Diego County Valleys. * WHEN...Until 8 PM PDT Thursday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car

* WHAT...Dangerously hot conditions with high temperatures as high as 108 on Thursday possible. Nights will be quite warm with low temperatures in the mid 70s to lower 80s. * WHERE...Coachella Valley, San Diego County Deserts, and San Gorgonio Pass near Banning. * WHEN...From 10 AM Wednesday to 8 PM PDT Friday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.

* WHAT...Dangerously hot conditions with high temperatures ranging from the mid 80s to lower 90s at the beaches to the mid to upper 90s near higher coastal terrain. Nights will be very warm with low temperatures in the lower to mid 70s. * WHERE...Orange County Coastal Areas. * WHEN...Until 8 PM PDT Thursday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.

* WHAT...Dangerously hot conditions with high temperatures in the upper 90s to 105. Nights will be very warm with low temperatures in the upper 60s to mid 70s. * WHERE...San Bernardino and Riverside County Valleys-The Inland Empire. * WHEN...Until 8 PM PDT Thursday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car

* WHAT...Sub-freezing temperatures as low as 25F expected. * WHERE...Central Interior Cumberland and Androscoggin Counties. * WHEN...From midnight tonight to 8 AM EDT Wednesday. * IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. Take steps now to protect tender plants from the cold.

* WHAT...Temperatures at or below 32 degrees expected. * WHERE...Northern Saratoga, Northern Washington, Southeast Warren, and Southern Washington Counties. * WHEN...From midnight tonight to 8 AM EDT Wednesday. * IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. Take steps now to protect tender plants from the cold.