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Angeles National Forest
Dispatch Area Discussion...
346 PM PST TUE NOV 24 2009
STRONG OFFSHORE FLOW CONTINUES AS HIGH PRESSURE REMAINS ANCHORED
OVER THE GREAT BASIN. GUSTY WINDS AND VERY LOW HUMIDITIES ARE
EXPECTED TO CONTINUE RIGHT ON THROUGH THURSDAY MORNING, WITH THE
LOW HUMIDITIES LASTING THROUGH THURSDAY EVENING. THE STRONGEST
WINDS WILL OCCUR TODAY AND WEDNESDAY ACROSS VENTURA AND LOS ANGELES
COUNTIES, WITH SOMEWHAT LESS WIND ON THANKSGIVING DAY. OVERNIGHT
HUMIDITY RECOVERIES WILL BE POOR ACROSS THOSE AREAS AS WELL. AFTER
COORDINATION WITH LOCAL AGENCIES, A RED FLAG WARNING HAS NOT BEEN
ISSUED DUE TO LIVE FUEL MOISTURES BEING ABOVE CRITICAL LEVELS.
HOWEVER, DEAD FUEL MOISTURES ARE EXTREMELY LOW AND BECAUSE OF THIS
THERE IS STILL A VERY HIGH FIRE DANGER. THE SITUATION WILL BE
CLOSELY MONITORED AND THE POTENTIAL STILL EXISTS FOR A RED FLAG
WARNING TO BE POSTED FOR THIS EVENT SHOULD IT BE DETERMINED THAT THE
FUELS ARE DRY ENOUGH TO SUPPORT IT.
OFFSHORE FLOW WILL WEAKEN RAPIDLY THANKSGIVING DAY AS A LOW PRESSURE
AREA APPROACHES THE AREA FROM THE WEST. ALTHOUGH NO PRECIPITATION
IS EXPECTED LOCALLY FROM THIS SYSTEM, IT WILL USHER IN MUCH COOLER
TEMPERATURES AND HIGHER HUMIDITIES TO THE AREA STARTING FRIDAY AS
ONSHORE FLOW RETURNS.
THE RETURN TO ONSHORE FLOW WILL BE EXTREMELY BRIEF AS SURFACE HIGH
PRESSURE QUICKLY BUILDS OVER THE GREAT BASIN FRIDAY NIGHT INTO
SATURDAY. THIS WILL BRING ANOTHER ROUND OF GUSTY SANTA ANA WINDS TO
THE AREA WITH HUMIDITIES AGAIN DROPPING TO BELOW CRITICAL LEVELS.
INITITALLY TEMPERATURES WILL BE QUITE A BIT COOLER THAN THE CURRENT
OFFSHORE WIND EVENT DUE TO THE COLD AIR FROM FRIDAY`S LOW PRESSURE
SYSTEM. HOWEVER, THE HUMIDITY AND WIND COMPONENT OF THE RED FLAG
WARNING SYSTEM WILL LIKELY BE MET OVER THE WEEKEND AND POSSIBLY INTO
MONDAY AS WELL. ISSUANCE OF ANY WATCHES OR WARNINGS WILL REQUIRE
COORDINATION WITH AGENCIES AND INPUT ON FUEL CONDITIONS.
Forecast Issuance time: 330 PM PST TUE NOV 24 2009
TONIGHT...
SKY/WEATHER.........CLEAR.
MIN TEMPERATURE.....54-64 LOW ELEVATIONS TO 30-40 IN HIGH VALLEYS
AND PEAKS.
24 HR TREND......LITTLE CHANGE.
MAX HUMIDITY........10-20 PERCENT...EXCEPT 35-50 PERCENT
IN HIGH VALLEYS.
24 HR TREND......DOWN 10.
20-FOOT WINDS.......
VALLEYS/LWR SLOPES...NORTHEAST 15-25 MPH. GUSTS TO 45 MPH BELOW
PASSES AND CANYONS.
RIDGES/UPR SLOPES....NORTHEAST 20-30 MPH. LOCAL GUSTS TO 50 MPH.
MARINE LAYER........NONE.
LAL.................1.
CWR (>0.10 IN)......0 PERCENT.
WEDNESDAY...
SKY/WEATHER.........SUNNY.
MAX TEMPERATURE.....69-79 LOW ELEVATIONS TO 55-65 HIGHER PEAKS.
24 HR TREND......LITTLE CHANGE.
MIN HUMIDITY........6-12 PERCENT.
24 HR TREND......LITTLE CHANGE.
20-FOOT WINDS.......
VALLEYS/LWR SLOPES...NORTHEAST 15-25 MPH. GUSTS TO 45 MPH BELOW
PASSES AND CANYONS.
RIDGES/UPR SLOPES....NORTHEAST 20-30 MPH. LOCAL GUSTS TO 50 MPH.
MARINE LAYER........NONE.
LAL.................1.
CWR (>0.10 IN)......0 PERCENT.
WEDNESDAY NIGHT...
SKY/WEATHER.........CLEAR.
MIN TEMPERATURE.....48-58 LOW ELEVATIONS TO 30-40 IN HIGH VALLEYS
AND PEAKS.
MAX HUMIDITY........10-20 PERCENT...EXCEPT 35-50 PERCENT HIGH VALLEYS.
20-FOOT WINDS.......
VALLEYS/LWR SLOPES...NORTHEAST 15-25 MPH. GUSTS TO 35 MPH BELOW
PASSES AND CANYONS.
RIDGES/UPR SLOPES....NORTHEAST 15-25 MPH. LOCAL GUSTS TO 40 MPH.
LAL.................1.
CWR (>0.10 IN)......0 PERCENT.
THANKSGIVING DAY...
SKY/WEATHER.........SUNNY.
MAX TEMPERATURE.....67-77 LOW ELEVATIONS TO 54-63 HIGHER PEAKS.
MIN HUMIDITY........6-12 PERCENT.
20-FOOT WINDS.......
VALLEYS/LWR SLOPES...NORTHEAST 15-25 MPH. LOCAL GUSTS TO 35 MPH IN THE
MORNING BELOW PASSES AND CANYONS.
RIDGES/UPR SLOPES....EAST 8-16 MPH. LOCAL GUSTS TO 30 MPH IN
THE MORNING.
LAL.................1.
CWR (>0.10 IN)......0 PERCENT.EXTENDED...
.FRIDAY...MOSTLY CLEAR. LOWS IN THE UPPER 30S AND 40S LOW ELEVATIONS
TO THE 30S TO LOWER 40S IN HIGH VALLEYS AND PEAKS. HIGHS IN THE
UPPER 50S AND 60S LOW ELEVATIONS TO THE UPPER 40S TO MID 50S HIGHER
PEAKS. NORTH WINDS 10 TO 20 MPH.
.SATURDAY...WINDY. MOSTLY CLEAR. LOWS IN THE 30S AND 40S. HIGHS IN
THE MID 50S TO MID 60S LOW ELEVATIONS TO NEAR 50 HIGHER PEAKS.
NORTHEAST WINDS 20 TO 30 MPH. LOCAL GUSTS TO 60 MPH.
.SUNDAY...WINDY. MOSTLY CLEAR. LOWS IN THE 30S TO MID 40S. HIGHS IN
THE UPPER 50S TO LOWER 70S. NORTHEAST WINDS 20 TO 30 MPH. LOCAL
GUSTS TO 60 MPH.
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