Storm Prediction Center Fire Weather Outlook

• Day 1 fire weather outlook and map
• Day 2 fire weather outlook and map

Day 1 Fire Weather Outlook

	    
   NWS Storm Prediction Center Norman OK
   0128 AM CDT Thu Aug 24 2017

   Valid 241200Z - 251200Z

   ...CRITICAL FIRE WEATHER AREA FOR SCATTERED DRY THUNDERSTORMS ACROSS
   PARTS OF NORTHEAST OR...CENTRAL ID...AND SOUTHWEST MT...

   ...Synopsis...
   An upper trough/low will continue eastward across BC into AB and the
   Pacific Northwest today. Enhanced mid-level west-southwesterly winds
   will overspread much of the northwestern CONUS. At the surface, a
   cold front attendant to a low over central/southern AB will sweep
   eastward across the interior Pacific Northwest, northern Rockies,
   and northern High Plains through tonight.

   ...Portions of the Interior Pacific Northwest into the Northern
   Great Basin/Rockies: Dry Thunderstorm Threat...
   Isolated to scattered thunderstorms will develop this afternoon from
   eastern OR into the northern Great Basin/Rockies and adjacent High
   Plains as large-scale ascent attendant to the previously mentioned
   upper trough overspreads these regions. Precipitable water values
   generally 0.7-1.0 inch, dry sub-cloud layers, and fast storm motions
   owing to the enhanced mid-level winds associated with the upper
   trough should act to limit wetting rainfall potential with this
   convection. Accordingly, an isolated dry thunderstorm area has been
   continued to account for the threat of new lightning-induced fire
   starts where fuels are dry/receptive. A scattered dry thunderstorm
   delineation also exists across parts of northeastern OR into central
   ID and southwestern MT where a gradient in precipitable water values
   will be present. Latest short-term guidance remains consistent in
   showing this corridor as having the greatest convective coverage
   this afternoon and evening.

   ...Portions of the Interior Pacific Northwest: Wind/RH Threat...
   As the axis of the upper trough pivots over the Pacific Northwest,
   strong/gusty low-level winds are forecast to develop across mainly
   interior portions of WA/OR and far northern ID this afternoon.
   Sustained westerly to southwesterly winds of 15-20 mph will occur
   behind the surface cold front, with some channeling and localized
   higher gusts in the eastern Columbia Basin. RH values are expected
   to become only marginally reduced, generally into the 15-20% range.
   However, dry to very dry fuels and the forecast meteorological
   conditions will support elevated to locally critical conditions
   across parts of central/eastern WA, northern OR, and the Panhandle
   of ID this afternoon and evening.

   ...Portions of the Northern High Plains: Wind/RH Threat...
   The surface pressure gradient will increase across the northern High
   Plains today between a deepening surface low over central/southern
   AB and high pressure over ON and the Great Lakes. A corresponding
   strengthening of low-level south-southeasterly winds is expected
   across the northern High Plains in advance of the previously
   mentioned cold front, with sustained surface winds of 15-20 mph
   probable. Moisture return should be rather limited across this
   region owing to a prior frontal passage, and RH values may become
   lowered into the 15-25% range by this afternoon across parts of
   eastern MT and vicinity. With generally dry fuels across this
   region, an elevated area has been maintained with no changes. The
   lack of an even stronger forecast winds and a warmer/drier low-level
   airmass continues to preclude a critical area.

   ..Gleason.. 08/24/2017

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

      

Day 2 Fire Weather Outlook

 Storm Prediction Center Norman OK
   0130 AM CDT Thu Aug 24 2017

   Valid 251200Z - 261200Z

   ...Synopsis...
   An upper trough/low is forecast to move northeastward across AB/SK
   on Day 2/Friday, while a corridor of modestly enhanced mid-level
   westerly winds remains across parts of the Pacific Northwest into
   the northern Rockies/High Plains. At the surface, a cold front will
   continue eastward across the northern Plains, while becoming nearly
   stationary and ill-defined across the northern Rockies/Great Basin.

   ...Portions of the Northern Rockies...
   A weak shortwave trough embedded within westerly mid-level flow
   should move across the Pacific Northwest into the northern Rockies
   on Day 2/Friday. Large-scale ascent and orographic circulations will
   likely promote isolated thunderstorms across the Bitterroot Range of
   ID into southwestern MT Friday afternoon/evening. Although low-level
   temperatures may be somewhat cooler compared to Day 1/Thursday,
   there is still forecast to be enough reduction in boundary layer
   moisture to support well mixed and dry sub-cloud layers.
   Furthermore, modestly enhanced westerly winds will likely encourage
   fast storm motions, which may limit substantial wetting rainfall
   outside of the heaviest cores. With fuels expected to remain
   generally receptive to new lightning-induced fire starts, an
   isolated dry thunderstorm area has been introduced for a small
   portion of the northern Rockies.

   ..Gleason.. 08/24/2017

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

      

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