Forecasters expect a warm Fall in the United States

Temperature outlook, September through November, 2017
Temperature outlook, September through November, 2017.

Weather forecasters just released their three-month outlook for September through November in the United States. If correct, it will be warmer than normal across the entire country and the precipitation will be close to average except in the Southeast where they expect wetter conditions. This could lead to extended Autumn wildfire seasons.

Precipitation outlook, September through November
Precipitation outlook, September through November, 2017.

Wildfire potential — August through November

The prediction for August shows enhanced fire potential for the Northern Rockies, Northern Nevada, and much of California and the Northwest.

On August 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for August through November. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

It revises the outlook that was issued for August a month ago, adding to the “Above Normal” category Northern Idaho, the eastern halves of Oregon and Washington, and Western Montana. Many of the August “Above Normal” areas will carry over into September except for the areas in Oregon and Washington.

Below are:

  • the highlights of the NIFC report;
  • NIFC’s graphical outlooks for September through November;
  • Drought Monitor, and;
  • NOAA’s long range temperature and precipitation forecasts.

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The seasonal transition of the western fire season north has occurred. A strong southwestern monsoon has developed over the Southwest and has reduced the significant large fire potential and activity across the Four Corners Region. Significant lightning activity associated with the monsoon has spread north creating numerous incidents across the northern Great Basin, Northern California, Pacific Northwest, and the Northern Rockies. With the fine fuels now fully cured and with larger fuels now receptive, even at the higher elevations, fire activity is increasing as it nears its seasonal peak in August. While the northwestern states have shown a significant upturn in activity, fire activity in Alaska has begun to wane with the arrival of the late summer rains across the Alaskan Interior. The eastern and southeastern states have seen and will continue to experience overall limited activity as the regions remain largely out of season.

Precipitation received was generally well below average across the western half of the country in July. With the occurrence of three significant heat wave events, fuels dried quickly and became receptive to fire earlier than in most years. By month’s end, the previous winter’s record snowpack and above average spring rainfall was a distant memory. Drought was beginning to reemerge in the Rockies and across portions of the Pacific Northwest. Across the northern Great Plains, the established long term drought conditions continued to worsen. Large fire activity became problematic across eastern Montana, Wyoming and the Dakotas.

Looking forward to the peak of the western fire season in August and September, conditions are expected to remain favorable for the Above Normal significant fire activity to continue. Areas with the greatest potential for significant large fire activity will be the grasses and rangelands of the Pacific Northwest east of the Cascades, the lower and middle elevations across California, most of the Northern Rockies region. The grass and rangelands across the northern Great Basin will also continue to demonstrate Above Normal significant large fire potential and activity.

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September wildfire potential

October November wildfire potential

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drought monitor

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90 day outlook weather

Excessive Heat Warnings and Watches starting Monday on west Coast

(Updated at 8 a.m. MDT July 31, 2017)

excessive heat warning
The red areas indicate warnings for excessive heat through Thursday August 3 with temperatures at various times reaching into the triple digits — even in the Seattle area on Thursday.

Above: excessive heat warnings. Below: Red Flag Warnings and Fire Weather Watches. All were updated at 7:50 a.m. MDT July 31, 2017.

wildfire danger red flag warning
The red areas are under a Red Flag Warning on Monday. The yellow areas indicate Fire Weather Watches for elevated wildfire danger for the next several days.

Firefighters: be careful out there. It’s a good time to review how to prevent and deal with heat related illnesses. Drinking water is important, but it will not prevent heat exhaustion, heat stroke, or rhabdo. And those last two can kill.

Large fire whirl on Gorman Fire

This is a very impressive large fire whirl over the Gorman Fire Friday in Los Angeles County, filmed by Kevin Takumi for FoxLA.com

The images are screenshots from Mr. Takumi’s video.

fire whirl gorman fire

Wildfire potential July through October

Potential wildfire July

 

On July 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for July through October. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

If it is accurate firefighters could be busy at times in California, the Great Basin, and the Northern Rockies.

Below are:

  • the highlights of the NIFC report;
  • NIFC’s graphical outlooks for July through October;
  • Drought Monitor, and;
  • NOAA’s long range temperature and precipitation forecasts.

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Fire activity across the West began to increase significantly in June as preexisting dry conditions along with record setting heat events allowed for the fuels to become critically dry across portions of the Southwest, southern Great Basin, and Southern California. By month’s end, fire activity began its usual expansion northward as fires became more frequent in the lower and middle elevations. Several wetting systems slowed fire activity in Alaska. The fire season in Georgia and Florida diminished as multiple wetting rain events relieved the pre existing drought conditions.

Timely precipitation along with above average soil moisture has led to the growth of an abundant crop of fine fuels across much of the west. Periodic cooler than average temperatures across the northwestern portion of the country has slowed curing and drying rates in the grasses and has continued to slow the melting rates of the remaining snowpack. The southwestern states, however, have been drier and more continuously warm than average for several months making fuels more receptive to fire activity. Due to below average precipitation received across the Great Plains portions of eastern Montana and the Dakotas should be monitored closely for a possible increase in fire activity in July. The eastern U.S. been largely milder than average as several frontal systems produced significant rainfall.

Above normal significant fire potential is expected across a large portion of the rangelands of the west through August before trending toward normal in September and October with seasonal changes that bring wetting precipitation. The Southwest can expect a typical end to its fire season as monsoonal moisture becomes more firmly established by the end of July. Higher elevations across northwestern states will continue to experience below normal significant fire potential in July followed by normal potential for August as high elevation heavy fuels begin to dry out. A normal reduction of fire activity is expected in September across much of the west. The eastern half of the nation is in full green-up and fuels are generally not receptive to significant fire activity. Expect these conditions to persist into fall.

wildfire potential August wildfire potential September October

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Drought Monitortemperature outlook precipitation outlook

Wildfire potential June through September

On June 1 the Predictive Services section at the National Interagency Fire Center issued their Wildland Fire Potential Outlook for June through September. The data represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

If it is accurate it looks like firefighters could be busy at times in Arizona, California, and Nevada, but not so much in the rest of the Western U.S.

Below are:

  • the highlights of their report;
  • NIFC’s graphical outlooks for June through September;
  • the Drought Monitor, and;
  • NOAA’s long range temperature and precipitation forecasts.

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“Florida and Georgia experienced slight relief during the latter half of May as moderately wet systems produced widespread precipitation in both states. Activity across the southwest including Southern California began to increase toward month’s end as the region began to enter its core fire season. Nationally, the acres burned were above average at the end of May largely due to the fire activity that occurred in early March across the southern Great Plains where more than a million acres burned. The number of fires may be a more reflective number this year and remains below average for 2017.

Above normal precipitation and soil moisture is leading to a robust green-up across the West. Overall cooler than average temperatures and a heavy snowpack have led to slower than normal melting of the mountain snowpack in nearly all locations across the West. This should lead to a delayed start to the fire season in the higher elevations which may, in turn lead to a compressed season.

Above normal large fire potential will continue across southeastern Georgia and Florida into mid-June before the cumulative effects of precipitation events begin to take hold. Below Normal potential is expected across most of the remainder of the southeast through July before returning to Normal for August and September. Recent dry conditions across the southwest will lead to Above Normal potential across southeastern Arizona and Southern California. Below Normal to Normal large fire potential is also expected in the a majority of the higher elevations across the West in June and July.

July and August may be periods of concern. Above Normal potential is expected across the western portion of the Great Basin and across the middle elevations in California in July and August after the abundant grass crop cures. Fire activity will be mostly driven by short term weather events. Looking north, Alaska appears to be transitioning into a normal fire season for June and July with late summer rains ending the season across the interior in August. Extended dry conditions on the west side of the big island in Hawaii will lead to Above Normal potential that should last into September.”

wildfire potential July 2017

wildfire potential August September 2017

Continue reading “Wildfire potential June through September”