Weather Alerts for Big Bear Valley

Issued by the National Weather Service

Red Flag Warning  RED FLAG WARNING   Red Flag Warning
BIG BEAR VALLEY

Areas Affected:
East Bay Hills and the Diablo Range - East Bay Interior Valleys - North Bay Mountains
Effective: Sun, 9/19 11:00pm Updated: Mon, 9/20 2:04am Urgency: Expected
Expires: Mon, 9/20 8:00pm Severity:  Severe  Certainty: Likely

 
Details:
...Red Flag Warning 11 pm Sunday through 8 pm Monday for the
North and East Bay hills as well as the East Bay interior
valleys...
.Dry northerly offshore winds will push into the Napa hills
late tonight and then gradually spread over the North and East
Bay hills. The initial burst of winds will occur while humidity
values remain fairly moist. However the dry offshore winds will
begin a rapid drying of the atmosphere with humidity values
dropping quickly by Monday morning. Continued moderate offshore
winds on Monday as humidity values drop into the teens. Offshore
winds will ease by sunset Monday night. Little or no humidity
recovery Monday night into Tuesday morning but with only light
offshore winds.
...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM PDT MONDAY FOR
DRY OFFSHORE WINDS FOR THE NORTH BAY MOUNTAINS AND EAST BAY HILLS
AND INTERIOR VALLEYS...
* AFFECTED AREA...Fire Weather Zone 507 North Bay Mountains,
Fire Weather Zone 510 East Bay Interior Valleys and Fire
Weather Zone 511 East Bay Hills and the Diablo Range.
* TIMING...11 PM Sunday night to 8 PM Monday evening. Initial
burst of gusty offshore winds overnight to mid morning Monday.
Drier conditions but lighter winds Monday daytime. Offshore
winds ease Monday night with continued poor humidity recovery.
* WINDS...Northeast 10 to 20 mph with gusts up to 40 mph. Local
gusts up to 50 mph over the highest peaks.
* RELATIVE HUMIDITY...Initially 30-45% tonight drying to 15-30%
on Monday with little or no recovery Monday night.
* IMPACTS...Any fire starts would likely see rapid spread due to
dry fuels, low humidity and gusty winds in areas that did not
receive wetting rains over the last 24 hours.

Information:
A Red Flag Warning means that critical fire weather conditions
are either occurring now...or will shortly. A combination of
strong winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.