Storm Prediction Center
Day 1 and Day 2 Fire Weather Outlooks

Day 1 Fire Weather Forecast graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast

Click for Day 1 FireWX Areal Outline Product

   FNUS21 KWNS 261601

   Day 1 Fire Weather Outlook  
   NWS Storm Prediction Center Norman OK
   1101 AM CDT Wed Jul 26 2017

   Valid 261700Z - 271200Z

   The ongoing isolated dry-thunderstorm area has been adjusted in two
   areas to reflect the latest observational/guidance trends. First,
   the area has been removed from portions of southern Idaho, where
   tropospheric moisture content appears too high for a substantial
   dry-thunderstorm threat today. Regardless, gusty outflow winds may
   lead to erratic behavior with ongoing fires. Second, the western
   portion of the dry-thunderstorm area has been expanded towards the
   northern Sierra Nevada. As the northern California impulse lifts
   east/northeast, ascent along its leading edge will bolster
   convective development on higher terrain today. The 12Z REV sounding
   sampled 0.74" of PW this morning, indicating an environment still
   favorable for a few dry storms and related ignitions.

   ..Picca.. 07/26/2017

   .PREV DISCUSSION... /ISSUED 0220 AM CDT Wed Jul 26 2017/

   The slow-moving midlevel low centered over northern CA is forecast
   to begin ejecting northeast today, though otherwise the pattern will
   change little compared to previous days, with an upper ridge
   persisting across the Southwest into the southern Plains. A weak
   surface ridge will settle into portions of the central and northern
   Plains in the wake of a cold front, resulting in light winds and
   slightly cooler conditions.

   ...OR/Northern CA eastward into southern MT...
   Scattered thunderstorms are expected over many of the same areas
   that have been affected on previous days, in advance of the
   persistent midlevel low over northern CA. Thermodynamic profiles
   will may be slightly cooler and more moist compared to previous
   days, due to the cumulative effects of repeated rounds of
   convection. However, widespread wetting rainfall is not anticipated,
   and some threat for lightning-related ignitions will continue where
   dry fuels remain across the region. As a result, the dry
   thunderstorm area is maintained across the area with only minor

   ...Please see for graphic product...

Day 2 Fire Weather Forecast graphic
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast

Click for Day 2 FireWX Areal Outline Product (KWNSPFWFD2)

   FNUS22 KWNS 261849

   Day 2 Fire Weather Outlook  
   NWS Storm Prediction Center Norman OK
   0149 PM CDT Wed Jul 26 2017

   Valid 271200Z - 281200Z

   No changes to the ongoing forecast are necessary. See below for more

   ..Picca.. 07/26/2017

   .PREV DISCUSSION... /ISSUED 0221 AM CDT Wed Jul 26 2017/

   The midlevel low/trough that has persisted for several days near
   northern CA is expected to weaken and become absorbed into broad
   southwesterly flow ahead of a strong cyclone over the northeast
   Pacific. At the surface, in response to the ejecting system, low
   pressure is expected to deepen slightly over portions of
   Alberta/Saskatchewan and the northern Rockies/High Plains, with
   generally weak surface features elsewhere across the CONUS. 

   ...Northern OR into Central/Eastern WA...
   Dry and breezy conditions are expected in the lee of the Cascades of
   WA/OR on Thursday, in the wake of a cold frontal passage. Current
   guidance suggests the potential for westerly winds of 15-20 mph and
   minimum RH values of 15-25%, sufficient for an elevated fire-weather
   risk. A modest increase in anticipated wind speeds would result in a
   critical threat across the area, but at this time confidence in
   sustained winds greater than 20 mph is too low for any upgrade. 

   ...ID into Western/Central MT and Northwest WY...
   Scattered thunderstorms are again expected as the aforementioned
   ejecting system moves across the area. Forecast thermodynamic
   profiles continue to suggest the potential for a mix of wet and dry
   thunderstorm activity, resulting in some threat for ignitions in
   areas of dry fuels. 

   ...Northern/Eastern MT into the Western Dakotas...
   A modest increase in surface winds is possible across portions of
   northern/eastern MT into the Western Dakotas, in response to
   developing low pressure over portions of AB/SK. Meanwhile, with
   low-level moisture expected to remain rather limited, strong heating
   could result in near-critical RH values during the afternoon. These
   factors could result in elevated fire weather conditions over
   portions of the region. However, quite a bit of uncertainty remains
   regarding the strength of low-level flow across the area, so no
   elevated delineation has been made at this time.

   ...Please see for graphic product...


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