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    Day 2 FW Outlook >
Sep 25, 2016 Day 1 Fire Weather Outlook
Updated: Sun Sep 25 16:35:02 UTC 2016 (Print Version | 20160925 1700Z Day 1 FireWX shapefile | 20160925 1700Z Day 1 FireWX KML)
Day 1 Fire
 Population  Cities/Towns  CWAs  Interstates  Counties  FEMA Regions  Day 1 Surface Analysis

Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
Critical 14,947 10,601,428 Los Angeles, CA...Riverside, CA...Glendale, CA...San Bernardino, CA...Ontario, CA...
   ZCZC SPCFWDDY1 ALL
   FNUS21 KWNS 251631

   DAY 1 FIRE WEATHER OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 AM CDT SUN SEP 25 2016

   VALID 251700Z - 261200Z

   ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...

   ...PORTIONS OF SOUTHERN CALIFORNIA...
   RECENT SURFACE OBSERVATIONS SAMPLED -11 MB LAX-TPH...-5 MB
   LAX-DAG...AND -7 SAN-LAS GRADIENTS. WIND SPEEDS HAVE BEEN GRADUALLY
   INCREASING OVER THE PAST FEW HOURS WITH MULTIPLE HIGH ELEVATIONS
   SITES NOW REPORTING NELY SUSTAINED WINDS AROUND 30 MPH. INTERIOR
   SITE AT ONT HAS ALSO REPORTED INCREASING WIND SPEEDS OVER THE PAST
   HOUR WITH THE LATEST OBSERVATION REPORTING SUSTAINED WINDS OF 20 MPH
   AND GUSTS OF 35 MPH. INCREASING TREND IS EXPECTED TO CONTINUE WITH
   WIDESPREAD GUSTY CONDITIONS ANTICIPATED THIS AFTERNOON. THESE STRONG
   WINDS COUPLED WITH TEMPERATURES IN THE UPPER 90S/LOW 100S AND MIN RH
   VALUES IN THE LOWER TEENS/SINGLE DIGITS WILL SUPPORT A WIDESPREAD
   CRITICAL FIRE THREAT TODAY. CRITICAL THREAT WILL EXTEND INTO THE
   EVENING AND OVERNIGHT AS POOR OVERNIGHT RECOVERY KEEP RH VALUES LOW
   AND WINDS REMAIN STRONG. THIS SCENARIO MATCHES WELL WITH THE
   PREVIOUS FORECAST AND NO CHANGES ARE NEEDED. 

   ...PORTIONS OF NORTHERN CALIFORNIA...
   RECENT SURFACE OBSERVATIONS REVEAL MOSTLY ELEVATED FIRE WEATHER
   CONDITIONS AT THE HIGHER ELEVATION SITES ACROSS THE REGION. SIMILAR
   CONDITIONS ARE EXPECTED ACROSS THESE AREAS THROUGHOUT THE DAY.
   ELEVATED CONDITIONS ARE EXPECTED ACROSS THE VALLEY DURING THE
   AFTERNOON AS TEMPERATURES CLIMB INTO THE UPPER 90S/LOW 100S AND RH
   VALUES DROP INTO THE SINGLE DIGITS. NO CHANGES ARE NEEDED TO THE
   PREVIOUS FORECAST. 

   ...PORTIONS OF THE NORTHERN/CENTRAL PLAINS...
   MINOR CHANGES WERE MADE TO THE PREVIOUS ELEVATED DELINEATION BUT THE
   OVERALL SCENARIO DESCRIBED IN THE PREVIOUS OUTLOOK /BELOW/ REMAINS
   VALID.

   ..MOSIER.. 09/25/2016

   .PREV DISCUSSION... /ISSUED 0315 AM CDT SUN SEP 25 2016/

   ...SYNOPSIS...
   A MID/UPPER-LEVEL TROUGH EXTENDING FROM NORTHERN MEXICO TO THE
   NORTHERN PLAINS WILL SHEAR INTO TWO DISTINCT AREAS TODAY -- A CLOSED
   CYCLONE DRIFTING SOUTHWEST TOWARDS THE GULF OF CALIFORNIA...AND THE
   REMAINDER OF THE ORIGINAL TROUGH OVER THE NORTHERN PLAINS AND UPPER
   MIDWEST. TO THE WEST OF THIS TROUGH...RIDGING WILL BUILD OVER PARTS
   OF THE PACIFIC NORTHWEST AND GREAT BASIN.

   ...PORTIONS OF SOUTHERN CALIFORNIA...
   WIDESPREAD CRITICAL FIRE-WEATHER CONCERNS ARE EXPECTED ACROSS PARTS
   OF SOUTHERN CA TODAY...WITH VERY DRY FUELS AND GUSTY WINDS FAVORING
   RAPID FIRE SPREAD. 07Z OBSERVATIONS DEPICT SOME ELEVATED CONDITIONS
   ONGOING ACROSS HIGHER TERRAIN...AND WINDS SHOULD FURTHER INCREASE
   TOWARD SUNRISE -- WITH SUSTAINED VALUES UPWARDS OF 20-30 MPH AND
   GUSTS TO 40-55 MPH -- AS THE SFC PRESSURE GRADIENT FURTHER
   STRENGTHENS. RH VALUES WILL FALL RAPIDLY AFTER SUNRISE...GENERALLY
   INTO THE 5-15 PERCENT RANGE ACROSS MUCH OF THE REGION...AS TEMPS
   CLIMB INTO THE 90S/LOWER 100S TODAY. DUE TO THE OFFSHORE ORIENTATION
   OF FLOW ALOFT...WINDS SHOULD NOT EXPERIENCE AS MUCH OF A DIURNAL
   WEAKENING AS IS TYPICAL. THUS...GUSTY OFFSHORE FLOW SHOULD PERSIST
   AS RH VALUES PLUMMET...SUPPORTING WIDESPREAD CRITICAL FIRE-WEATHER
   CONCERNS. TODAY SHOULD BE THE PEAK OF THE ONGOING OFFSHORE FLOW
   EVENT...WITH THE POTENTIAL FOR EXTREME FIRE BEHAVIOR FOLLOWING ANY
   IGNITIONS. MOREOVER...AS THE SFC PRESSURE GRADIENT STRENGTHENS AGAIN
   TONIGHT...CRITICAL CONDITIONS SHOULD CONTINUE THROUGH THE OVERNIGHT
   HOURS.

   ...PORTIONS OF NORTHERN CALIFORNIA...
   ELEVATED/LOCALLY CRITICAL FIRE-WEATHER CONCERNS ARE ANTICIPATED THIS
   MORNING THROUGH AT LEAST EARLY AFTERNOON ACROSS THE SACRAMENTO
   VALLEY AND SURROUNDING TERRAIN. AN ENHANCED SFC PRESSURE GRADIENT
   WILL SUPPORT BREEZY NORTHERLY FLOW ACROSS THE VALLEY...AND EASTERLY
   DOWNSLOPE WINDS OVER HIGHER TERRAIN. SUSTAINED WINDS AROUND 15-25
   MPH AND RH VALUES BELOW 15-20 PERCENT WILL RESULT IN
   ELEVATED/LOCALLY CRITICAL CONDITIONS TODAY...BEFORE WINDS WEAKEN
   SOME LATE THIS AFTERNOON INTO THE EVENING. SOME ENHANCEMENT OF
   EASTERLY WINDS ACROSS THE SIERRA NEVADA RANGE TONIGHT SHOULD THEN
   RESULT IN A RETURN OF ELEVATED CONCERNS LATE IN THE PERIOD.

   ...PORTIONS OF THE NORTHERN/CENTRAL PLAINS...
   WITHIN A DRY POST-FRONTAL AIR MASS...BREEZY NORTHWESTERLY WINDS
   SHOULD FOSTER ELEVATED CONDITIONS TODAY. SUSTAINED WINDS AROUND
   15-25 MPH THIS AFTERNOON WILL COMBINE WITH MIN RH VALUES AROUND
   18-25 PERCENT AND SUFFICIENTLY DRY FUELS TO ENHANCE FIRE-WEATHER
   CONCERNS.

   ...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...

   CLICK FOR DAY 1 FIREWX AREAL OUTLINE PRODUCT (KWNSPFWFD1)
      
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Page last modified: September 25, 2016
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