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< Day 2 FW Outlook    
Day 3-8 Fire Weather Outlook Issued on Aug 20, 2017
Updated: Sun Aug 20 20:45:03 UTC 2017  (Print Version)
Note: Fire weather probabilistic information in MS-Word or PDF.
Note: Through September 29, 2015 the SPC will issue Experimental Probabilistic Fire Weather Dry Thunder and Strong Wind Outlooks for Days 3 to 8 with individual web graphics. Mouse over or click on the tabs above the graphic to view daily Probabilistic Dry Thunder (DryT) and Strong Wind (Wind) Fire Weather Outlooks. Please read the Product Description Document (PDD) and provide feedback using this link: "
Categorical D3-8 FW Otlk D3 D4 D5 D6 D7 D8
Exp. DryT/LowRH/Wind D3 D4 D5 D6 D7 D8
Population Cities CWAs Interstates Counties FEMA Regions

Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D3Tue, Aug 22, 2017 - Wed, Aug 23, 2017 D6Fri, Aug 25, 2017 - Sat, Aug 26, 2017
D4Wed, Aug 23, 2017 - Thu, Aug 24, 2017 D7Sat, Aug 26, 2017 - Sun, Aug 27, 2017
D5Thu, Aug 24, 2017 - Fri, Aug 25, 2017 D8Sun, Aug 27, 2017 - Mon, Aug 28, 2017
(All days are valid from 12 UTC - 12 UTC)
   FNUS28 KWNS 202043

   Day 3-8 Fire Weather Outlook  
   NWS Storm Prediction Center Norman OK
   0343 PM CDT Sun Aug 20 2017

   Valid 221200Z - 281200Z

   At the start of the extended period, a mid/upper ridge is expected
   to temporarily build into portions of the interior Northwest and
   northern Rockies, ahead of a strong upper trough approaching the
   British Columbia coast. Further south, a weak and slow-moving upper
   trough is expected remain centered off of the California coast
   through Wednesday, then weaken with time and perhaps meander back
   over the eastern Pacific later in the period. With time next week,
   the strong upper trough is expected to move into southwest Canada
   and adjacent portions of the Northwest and northern Rockies/High
   Plains, sweeping a cold front through the region by the end of the
   week. Next weekend, a mid/upper-level ridge is expected to rebuild
   over much of the West, resulting in a return to primarily hot and
   dry conditions. 

   ...D3/Tuesday - D5/Thursday: Dry Thunderstorm Threat from the
   interior Northwest into the Northern Rockies/High Plains...
   On D3/Tuesday, moisture returning northward in advance of the weak
   system off of the CA coast will result in an increased chance of
   thunderstorms over portions of northern CA and southern OR. While
   coverage may be relatively limited and tied to terrain-based
   circulations, antecedent warm/dry conditions and deep, well-mixed
   afternoon boundary layers will result in a threat for isolated dry

   On D4/Wednesday, a larger area of the Northwest and northern Rockies
   is expected to be impacted by thunderstorms, as moisture spreads
   northeastward and a weak midlevel trough is drawn northward to the
   east of the weak eastern Pacific trough and in advance of the
   stronger system approaching British Columbia. Moisture may be
   sufficient to support locally wetting rainfall, but given dry fuels
   over the region, some fire weather threat from dry thunderstorms is
   expected to develop from OR/northern CA northeastward into western

   On D5/Thursday, the thunderstorm threat will continue but begin to
   end from west to east, as a cold front sweeps through the region.
   The greatest coverage will likely shift into portions of ID/MT, but
   with uncertainty regarding rainfall potential and timing of the cold
   front, only 10% dry-thunderstorm probabilities will be maintained at
   this time. 

   ...D4/Wednesday - D5/Thursday: Critical Wind/RH threat over the
   interior Northwest... 
   On D4/Wednesday, a modest increase in low-level flow is possible as
   the strong upper trough approaches, resulting in the potential for
   elevated conditions given very warm and dry conditions. At this
   time, the threat for critically strong wind speeds appears too low
   to include any critical probabilities. 

   On D5/Thursday, the dry and windy post-frontal regime will result in
   a threat of elevated/potentially critical wind/RH conditions across
   portions of central/eastern OR/WA, in the Columbia Gorge and the lee
   of the Cascades. Some uncertainty remains regarding the potential
   for critically low RH in the cooler post-frontal airmass, but it is
   quite possible that a critical area will be needed for some portion
   of the area in subsequent outlooks. 

   ...D6/Friday - D7/Saturday: Northern High Plains
   Elevated to potentially critical conditions will be possible in the
   post-frontal regime across portions of MT and perhaps the western
   Dakotas on D6/Friday, and a 40% area has been added to cover this
   threat. Some extension of this regime may extend into D7/Saturday,
   but low predictability precludes any additional probabilities at
   this time.

   ..Dean.. 08/20/2017

   ...Please see for graphic product...


Fire Wx Graphics | Links | Product Info | Fire Weather Composite Maps (updated 4 times daily)

To retrieve previous Day 3-8 FireWX outlooks, type in the date you wish to retrieve in YYMMDD (e.g., 060205 for Feb. 5, 2006).
Data available since January 1, 2006.
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