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    Day 2 FW Outlook >
Jun 23, 2018 Day 1 Fire Weather Outlook
Updated: Sat Jun 23 15:25:02 UTC 2018 (Print Version | 20180623 1700Z Day 1 FireWX shapefile | 20180623 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 63,311 587,184 Henderson, NV...St. George, UT...Flagstaff, AZ...Bullhead City, AZ...Kingman, AZ...
   FNUS21 KWNS 231524

   Day 1 Fire Weather Outlook  
   NWS Storm Prediction Center Norman OK
   1024 AM CDT Sat Jun 23 2018

   Valid 231700Z - 241200Z


   Critical fire weather conditions are expected to develop across
   portions of the southern Great Basin and into northern Arizona this
   afternoon/evening. Locally critical fire weather conditions
   (sustained surface winds of 10-20 mph; RH values of 5-20%) should
   develop across portions of eastern Utah and into western/southern
   Colorado this afternoon into the evening along/ahead of an
   approaching mid-level jet. The elevated area was expanded farther
   into Colorado to reflect this.

   Very hot/dry/unstable conditions (surface temperatures 100+ F and
   single digit RH) are expected to develop in the Sacramento Valley,
   which should locally enhance the thermal trough and surface winds.
   Farther south in the Central Transverse Ranges and vicinity, winds
   will increase as the pressure gradient enhances between onshore flow
   and hot/dry interior valleys. This will lead to locally critical
   fire weather conditions (sustained surface winds 10-20 mph; RH
   values of 5-20%) including wind gusts around 40 mph.

   ..Nauslar.. 06/23/2018

   .PREV DISCUSSION... /ISSUED 0147 AM CDT Sat Jun 23 2018/

   An upper-level trough will dig into the southern/eastern Great Basin
   today. Enhanced mid-level flow will exist across parts of western
   Nevada, Utah, and northern Arizona. At the surface, a trough will be
   draped from western Colorado into southern California.

   ...Great Basin and southwest CONUS...
   Critical fire weather conditions are expected for parts of the
   southern Great Basin and northern Arizona. Strong surface heating
   will help to mix down enhanced mid-level flow from a passing
   upper-level trough. A weak surface trough in the region will also
   aid in increasing surface winds. Across this area surface winds of
   25 mph will be common amidst 5-15% RH. Minor changes have been made
   to the critical area from the previous forecast to account for small
   shifts in where strong surface flow will exist. Some areas of
   eastern Utah may experience locally critical fire weather
   conditions, but winds will only intermittently reach 25 mph.

   Surrounding the critical area, a broad area of elevated fire weather
   conditions will exist. RH values of 5-15% will be common across
   these areas, but surface winds will not likely reach critical levels
   as these areas will be displaced from the strongest mid-level flow.

   ...Portion of the Sacramento Valley...Central Traverse Ranges and
   Strong mid-level flow along the backside of the upper-level trough
   will lead to elevated to locally critical fire weather conditions in
   the parts of the Sacramento Valley. RH will drop to 5-15% with
   downsloping flow, but surface winds will generally be to light at
   15-20 mph to warrant critical designation.

   Farther south, the approaching upper-level trough will lead to a
   deepening surface trough over southern California and southwest
   Nevada. This enhanced pressure gradient will lead to elevated to
   locally critical fire weather conditions in the Central Traverse
   Ranges and adjacent northern/eastern valleys. RH of 5-10% will be
   present with surface winds reaching 20-25 mph. Recent guidance
   suggests that locally critical areas within this region are likely;
   however, winds of 20+ mph will not generally persist for long enough
   periods to warrant an added critical region.

   ...Please see for graphic product...

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