from the National Weather Service:
A very warm and dry air mass under high pressure aloft has filled 
in the mountains and valley areas, and will change little through 
Tuesday. Gusty north winds will peak through Monday night over 
the favored areas, with gusts in the 30 to 50 mph range. This will 
likely result in critical fire weather conditions where the winds 
are the strongest, including most mountain areas, southern Santa 
Barbara County, and possibly the Santa Clarita Valley. Rapid fire 
spread should be expected if fire ignition occurs. The north winds 
will weaken on Tuesday but Los Angeles County will see a quick 
wind reversal to onshore by Tuesday afternoon. These onshore winds 
should strengthen Wednesday and Thursday, which means that the 
current Red Flag Warning for the Los Angeles County mountains may 
need to be extended through Wednesday or Thursday. 
 
...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM PDT TUESDAY FOR 
GUSTY NORTH WINDS OVER THE MOUNTAINS OF LOS ANGELES AND VENTURA 
COUNTIES... 
 
* Winds...Areas of northwest to north winds 15 to 30 mph with 
gusts 35 to 45 mph through early Tuesday morning, then becoming 
southwest 8 to 15 mph with gusts to 25 mph. 
 
* Relative Humidity...Minimum 4 to 12 percent. Little or no 
overnight recovery. 
 
* Temperatures...Max temperatures 94 to 104 degrees lower 
elevations. 
 
* Impacts...If fire ignition occurs, conditions are favorable 
for very rapid fire spread including long range spotting, and 
extreme fire behavior which would threaten life and property.