Storm Prediction Center Day 2 Fire Weather Outlook

Created: Mon Dec 4 16:51:02 UTC 2017 (20171204 2000Z Day 2 FireWX shapefile | 20171204 2000Z Day 2 FireWX KML)

Day 2 Fire Weather Forecast graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
Extreme 4,680 9,710,836 Santa Ana, CA...Anaheim, CA...Riverside, CA...Glendale, CA...San Bernardino, CA...
Critical 9,558 10,282,828 Los Angeles, CA...San Diego, CA...Long Beach, CA...Chula Vista, CA...Oceanside, CA...

Click for Day 2 FireWX Areal Outline Product (KWNSPFWFD2)

   ZCZC SPCFWDDY2 ALL
   FNUS22 KWNS 041649

   Day 2 Fire Weather Outlook CORR 2
   NWS Storm Prediction Center Norman OK
   1049 AM CST Mon Dec 04 2017

   Valid 051200Z - 061200Z

   CORRECTED FOR GRAPHIC

   ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR PORTIONS OF
   VENTURA...LOS ANGELES...ORANGE...SAN BERNARDINO...AND RIVERSIDE
   COUNTIES IN SOUTHERN CALIFORNIA...
   ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN CALIFORNIA...

   ...Portions of Southern California...

   The ongoing forecast is on track and no changes are needed. See
   discussion below for more details.

   ...Portions of the Central Plains to Lower MO Valley...

   Elevated fire weather conditions will extend from portions of the
   Nebraska Panhandle and northeast Colorado through Kansas and into
   western Missouri. Very dry air will settle across the region behind
   a cold front tracking across the region on Day 1/Monday. While high
   temperatures will be cool, mainly in the 40s to low 50s, deep
   boundary layer mixing will occur and RH values should fall to around
   20-30 percent. An intense mid/upper level jet streak is forecast
   over Kansas and northern Missouri through much of the day and
   surface winds will be quite breezy from the west/northwest at 15-25
   mph with gusts to 40 mph possible.

   ..Leitman.. 12/04/2017

   .PREV DISCUSSION... /ISSUED 0155 AM CST Mon Dec 04 2017/

   ...Synopsis...
   A large-scale upper trough over the central/eastern CONUS and
   Ontario will make only slow eastward progress on Day 2/Tuesday.
   Meanwhile, upper ridging over the eastern Pacific will become
   prominent across parts of the western CONUS by Tuesday night. At the
   surface, a broad area of strong high pressure will remain across the
   northern Rockies and Great Basin, supporting a strong offshore Santa
   Ana wind event across parts of southern CA.

   ...Portions of Southern CA...
   An extremely critical area has been included for parts of Ventura,
   Los Angeles, Orange, San Bernardino, and Riverside counties in
   southern CA for Day 2/Tuesday. This is a continuation and expansion
   of the extremely critical area valid for Day 1/Monday. Across these
   areas, sustained winds of 30-40 mph will very likely continue
   through at least Tuesday evening while the surface pressure gradient
   is maximized. Stronger gusts of 60-80 mph may occur in the higher
   terrain of these counties given enhanced northeasterly low-level
   flow that will remain present. These very strong downslope winds
   will act to warm/dry the low levels, and RH values will likely
   remain in the 5-10% range for much of Day 2/Tuesday. Fuels will also
   be very dry and receptive to large fire starts and extreme fire
   spread given the expected meteorological conditions. 

   Of note, downtown Los Angeles and much of the LA basin have been
   specifically excluded from the extremely critical area for Day
   2/Tuesday, as sustained winds will likely remain somewhat less
   (generally in the 20-30 mph range) per consensus of latest
   high-resolution guidance). Regardless, critical conditions are still
   expected for this major metro area and vicinity.

   Critical fire weather conditions will occur across a larger portion
   of southern CA surrounding the extremely critical area. Here,
   sustained winds of 20-30 mph will be common, with gusts of 45-60 mph
   likely in the mountains/foothills. RH values of 5-15% will also
   occur through the period due to continued downslope warming/drying
   of an already dry airmass. RH recovery late Tuesday into Wednesday
   morning will likely be very poor as winds will remain strong/gusty
   across much of southern CA. Consensus of latest guidance indicates
   the pressure gradient across this region may weaken somewhat from
   Tuesday night into early Wednesday morning, and wind speeds/gusts
   may lessen slightly as a result. However, critical fire weather
   conditions will likely continue across both the critical and
   extremely critical designations through early Wednesday morning (end
   of the Day 2/Tuesday period into Day 3/Wednesday).

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

      

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