INTERAGENCY FIRE WEATHER CENTER – PREDICTIVE SERVICES UNIT

 

THURSDAY, SEPTEMBER 21, 2017

SOUTHERN CALIFORNIA GEOGRAPHICAL AREA COORDINATION CENTER

RIVERSIDE, CALIFORNIA

***Very windy in the Sierras and across desert today***

***Much warmer and drier conditions with light offshore winds beginning Sunday***

A front will sweep through the district today, bringing strong winds and light rain showers during the afternoon.  Gusty west winds of 30-45 mph with gusts to 60 mph will be possible across the Sierras and the Kern County Mountains into adjacent areas of the Antelope Valley and the western half of the Owens Valley throughout the day.  Other areas, such as the Banning Pass and Cleveland National Forest will see winds of 20-35 mph this afternoon.  Some light rain will be possible later this morning into the afternoon across the Sierra Front Country and across the coastal plains and valleys.  All rainfall amounts will be under a quarter of an inch.  A dusting of snow will be possible in the Sierras above 7,000 feet.  Temperatures will be 10-15 degrees below normal today and Friday with highs in the upper 40s and 50s in the mountains to the 70s in the valleys.  Winds should drop off tonight over most areas, but some north and northwest winds will be possible late tonight into Friday across the I-5 Corridor and along the central coast into Santa Barbara County.  This weekend, high pressure will approach the area, leading to much warmer and drier weather.  Light offshore winds under 25 mph will be possible Sunday through Tuesday night. A warming trend will start on Saturday, and by Monday and Tuesday, valley temperatures will be back into the 90s.  Minimum RH will drop into the 10-15% range over much of Southern California below 5,000 feet.  Cooler weather may return toward the end of next week.

 

Very windy weather will allow for rapid rates of spread and long range spotting today in some of the windy areas.  However, high humidity, light precipitation and cloudy skies will keep ignition components very low today.  Early next week, much warmer and drier weather will provide optimal drying conditions and fuel moisture levels should fall rapidly.  Some IA will be likely in the urban interface areas and foothills of Southern California next week with rapid rates of spread in continuous fuels.  Dead fuel moisture readings may fall to below normal readings by the middle of next week.  Although winds will be light and most areas should see good recovery, a few breezy spots such as northern Ventura and Los Angeles County and the Santa Ana Canyon may see active burning at night.  Look for little IA and resource demand through Sunday then some light IA next week. 

 

For additional fuel and weather information, including the Santa Ana Wildfire Threat Index, please visit:

 

http://gacc.nifc.gov/oscc/predictive/weather/index.htm