Storm Prediction Center Day 1 Fire Weather Outlook

Created: Fri Nov 9 15:39:03 UTC 2018 ( | )

Click for Day 1 FireWX Areal Outline Product

   ZCZC SPCFWDDY1 ALL
   FNUS21 KWNS 091538

   Day 1 Fire Weather Outlook  
   NWS Storm Prediction Center Norman OK
   0938 AM CST Fri Nov 09 2018

   Valid 091700Z - 101200Z

   ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTH
   COASTAL RANGES INTO THE FOOTHILLS OF SOUTHERN CALIFORNIA...
   ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...

   Ongoing wildfires should remain resistant to control/suppression,
   especially across portions of southern California, through today
   given the critical/extremely critical fire weather conditions.
   Otherwise, forecast remains on track and no changes are necessary.
   Please see the discussion below for more details.

   ..Nauslar.. 11/09/2018

   .PREV DISCUSSION... /ISSUED 1251 AM CST Fri Nov 09 2018/

   ...Synopsis...
   Modest upper-level flow, prevalent along the upstream portion of a
   longwave trough, will traverse California throughout the day. An
   inverted surface trough will remain just offshore of California,
   with a 1030+ mb high situated over the Great Basin. The net result
   will be the development of a very strong synoptic scale pressure
   gradient, conducive for a strong offshore flow event, especially in
   terrain-favoring areas that may channel surface flow and support
   stronger wind speeds.

   ...Portions of Southern California...
   Widespread critical wind/RH conditions will be ongoing at the start
   of the day (i.e. 1200-1500 UTC), along the Santa Ynez to Laguna
   Mountain ranges in association with strong offshore flow. Latest
   high-resolution model guidance continues to indicate channeled
   downslope flow in terrain-favored areas along the western/southern
   slopes of the Santa Ynez, San Gabriel, and Santa Ana Mountains
   during the morning hours, with north-northeasterly winds sustaining
   near 30 mph, hence the continuation of the extremely critical risk
   delineation for these areas. In addition, critically low RH and
   downslope flow contributing to 15 mph winds are also expected during
   the morning hours along southern portions of the Sierra and the
   south Coast Ranges, with an elevated delineation in effect for these
   areas. During the late morning/early afternoon hours, channeled flow
   in terrain induced areas will weaken with time, with elevated to
   locally critical wind/RH conditions persisting across portions of
   southwest California through the remainder of the afternoon.
   Thereafter, as the synoptic scale pressure gradient begins to relax
   with the eastward departure of the longwave trough and associated
   surface high pressure, surface winds should drop to marginally
   elevated thresholds by the end of period.

   ...Northern California...
   Elevated to locally critical winds (15-20 mph) will be ongoing
   during the early morning hours, particularly along the western
   slopes of the Sierra and northern Coast Ranges. While critically low
   RH will remain across most of the discussion area throughout the
   morning/afternoon hours, surface winds are expected to weaken below
   15 mph by noon, as the synoptic-scale pressure gradient is expected
   to diminish across northern California first, before weakening
   farther south.

   ...Please see www.spc.noaa.gov/fire for graphic product...

      

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