weather Archives - Page 13 of 79

Wildfire potential to increase in the Northwest in August and September

Bill GabbertAugust 3, 2020August 4, 2020Uncategorizedpotential, weather1 Comment

Wildfire potential is expected to be above normal this Fall in the Southeast

The National Significant Wildland Fire Potential Outlook issued August 1 by the Predictive Services section at the National Interagency Fire Center for August through November predicts that the northwestern states will have above normal potential through September. In October and November that distinction shifts to California and the southeast.

The data from NIFC shown here represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

Below:

An excerpt from the NIFC narrative report for the next several months;
More of NIFC’s monthly graphical outlooks;
NOAA’s three-month temperature and precipitation forecasts;
Drought Monitor;
Keetch-Byram Drought Index.

“August represents the peak of fire season for the West and Above Normal significant fire potential is expected across much of the Great Basin, northern California, Pacific Northwest, and northern Rockies. The North American Monsoon is forecast to remain intermittent, which will provide chances of lightning without moisture surges extending into portions of the Great Basin, California, Pacific Northwest, and northern Rockies. Given the dry fuels, any lightning will likely result in increased fire activity and above normal significant large fire potential into September.

“As precipitation and cooler temperatures arrive in fall, areas of concern will shift southward to portions of California as offshore wind events become more likely. Without a robust monsoon and potentially delayed fall precipitation, fuels will remain very dry across much of California. With ENSO-neutral to potentially La Niña conditions, an increase of frequency of offshore wind events are possible. Additionally, drier than normal conditions are likely across much of the Southern Area given current long-term weather and climatological trends. However, an active hurricane season is a source of uncertainty.”

wildfire potential October — (We confirmed that the October graphic above was issued August 1, 2020 not July 1, 2020 as indicated. It is a typo.)

Outlook temperature precipitation — Outlook for temperature and precipitation in September, October, and November. Prepared July 16, 2020. NOAA.

Red Flag warnings in four states, July 10, 2020

Bill GabbertJuly 10, 2020UncategorizedRed Flag Warning, weather

High temperatures, low RH, and strong winds

The National Weather Service has issued Red Flag Warnings for July 10 in areas of Wyoming, South Dakota, Nebraska, and Colorado.

Darren Clabo, the South Dakota State Fire Meteorologist, tells us what to expect in his state:

“A Red Flag Warning is in effect for southwestern SD today from 1200 to 2100 hrs. See https://www.weather.gov/unr/ for details.

“A dryline will move pass through southwestern SD at noon today. Following it, temperatures will rise to near 100, RH will drop below 10%, and westerly winds will gust up to 40 mph creating very critical fire weather conditions. Later this evening, a cold front will then move through which will switch the winds to the north but the winds will remain strong through 2200 hrs. No precipitation is expected over southwestern SD with the cold front passage. There will be a ~10 hour window of extremely critical fire weather conditions. Stay aware of your surroundings when on initial attack. This primarily affects Fall River, Custer, and Oglala Lakota Counties.

“Elsewhere across the state, severe weather is likely with large to very large hail, strong winds, and a few tornadoes possible.”

(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)

Above normal wildfire activity predicted to expand from the Great Basin into the Northwest and Northern Rockies

Bill GabbertJuly 1, 2020Uncategorizedpotential, weather2 Comments

Today the Predictive Services section at the National Interagency Fire Center issued their National Significant Wildland Fire Potential Outlook for July through October.

In July and August above normal wildfire potential is predicted to grow west and north across northern California, the Great Basin and the Central Rockies then expand into the Pacific Northwest and the Northern Rockies.

The data from NIFC shown here represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

Below:

An excerpt from the NIFC narrative report for the next several months;
More of NIFC’s monthly graphical outlooks;
NOAA’s three-month temperature and precipitation forecasts;
Drought Monitor;
Keetch-Byram Drought Index.

“Precipitation was below average in June across most of the country except across the Pacific Northwest where amounts were generally 150% of average or greater. Areas of concern emerged across California, the Great Basin, and Arizona where less than 5% of monthly precipitation was received. Temperatures were generally a few degrees above normal along the Pacific Coast and a few degrees below normal across the Interior West. In the East, temperatures were generally near normal in June.

“July is the entry point into the core of the Western Fire Season. As the season sequentially expands west and north across California, the Great Basin and the Central Rockies into the Northern Rockies and the Pacific Northwest, it will encounter areas of intensifying and expanding drought. This will lead to Above Normal significant large fire potential across large portions of the Great Basin and Northern California that will expand further north into the Pacific Northwest and Northern Rockies in August and September.

“The elevated potential in southwestern areas will begin to diminish with the arrival of the monsoon in early July. Activity will linger into mid-September in northern areas until the seasonal transition begins and begins to bring the season to a close. In Alaska, significant large fire activity will become less frequent in late July as returning moisture events gradually reduce the fire potential.”

Temperature and precipitation forecast for July.

Three Month weather Outlook — Temperature and precipitation forecast for August, September, and October.

Drought Monitor issued June 25, 2020 — Drought Monitor — June 23, 2020.

Keetch-Byram Drought Index, June 30, 2020.

Wildfire potential in the southwest is higher than in 2019

Bill GabbertJune 13, 2020June 13, 2020UncategorizedArizona, Energy Release Component, New Mexico, weather

The Energy Release Component in Arizona and New Mexico is average or above for the date, but considerably higher than last year

For the past two weeks most of the largest wildfires in the United States have been in Arizona, and recently the number of fires in New Mexico has also been increasing.

One of the reasons for this trend is reflected in the Energy Release Component (ERC) which is monitored from data collected at dozens of fire weather stations in the two states.

The ERC is an index indicating how hot a fire could burn. It is directly related to the 24-hour, potential worst case within the flaming front at the head of a fire.

The ERC can serve as a good characterization of a fire season since it tracks seasonal fire danger trends well. Fuel loading, woody fuel moistures, and larger fuel moistures all have an influence on the ERC, while the lighter fuels have less influence and wind speed has none. ERC has low variability, and is the best fire danger component for indicating the effects of intermediate to long-term drying on fire behavior.

Energy Release Component Arizona — Energy Release Component, average of fire weather stations in Arizona.

During the first six months of 2019 the statewide averages of ERC in Arizona and New Mexico were significantly below average, especially during May and June. So far during those two months this year the average ERCs have been slightly above average or well above. For the past week or so the statewide averages in the southwest have been above the 90^th percentile and are nearing the 97^th.

Click here to see ERC details at each of the fire weather stations in Arizona and New Mexico.

The weather forecasts for the next couple of weeks indicate that there is not much reason to think the ERCs will dip below average. WeatherUnderground predicts little or no rain in Phoenix, Flagstaff, or Albuquerque through the end of June. But the National Weather Service’s 8-14 day outlook predicts slightly higher probability of precipitation during that 7-day period, but with higher than normal temperatures.

8-14 day temperature and precipitation forecast. NWS.

On June 1 the Predictive Services office at the National Interagency Fire Center concluded the fire potential during June and July would be higher than normal in northwest New Mexico and most of Arizona.

Below are excerpts from NIFC’s June 1 wildfire outlook in the section about Arizona and New Mexico:

“Above Normal significant large fire potential is expected across most of Arizona and northwestern New Mexico through mid-July followed by a return to Normal potential after mid-July as the monsoon arrives. Other locations across the region can expect Normal significant large fire potential.

“Over the past two months, average high temperatures have been from 1-4 degrees above Average west of the divide and generally between 2-6 degrees above average further east. Some spots in eastern New Mexico have seen high temperatures from 6-8 degrees above average. As far as precipitation, most portions of the region have seen much drier conditions over the past 60 days.

“Significant Large Fire potential is anticipated to remain Normal for many areas east of the [Continental] Divide during the month of June while most portions of Arizona into northwestern and northern New Mexico will experience Above Normal significant large fire potential. The fine fuels will be the continued focus of fire activity entering June until the larger fuels become receptive mid-month and remain so until the monsoon’s arrival in mid-July.”

Wildfire potential expected to be above normal in many western locations this summer

Bill GabbertJune 1, 2020Uncategorizedpotential, weather3 Comments

July could be a very busy month for wildland firefighters in the U.S.

The National Significant Wildland Fire Potential Outlook issued today by the Predictive Services section at the National Interagency Fire Center for June through September indicates that many areas in the western United States will have above normal potential for wildfires. In July the increased fire danger is expected to affect significant portions of California, Washington, Oregon, Montana, Idaho, Nevada, Utah, Colorado, New Mexico, Hawaii, and Arizona.

The wildfire potential in the southern states is predicted to be below normal.

The data from NIFC shown here represents the cumulative forecasts of the ten Geographic Area Predictive Services Units and the National Predictive Services Unit.

Below:

An excerpt from the NIFC narrative report for the next several months;
More of NIFC’s monthly graphical outlooks;
NOAA’s three-month temperature and precipitation forecasts;
Drought Monitor;
Keetch-Byram Drought Index.

“June through early July is the peak of the fire season across the Southwest. Expect for the normal fire activity across the region to increase through the period with some areas experiencing Above Normal significant large fire potential, especially across Arizona. As the monsoon begins in mid-July, activity across the Southwest will diminish. Activity across Alaska will also diminish as the rainy season begins. California, central and northern portions of the Great Basin, the Pacific Northwest, and the Northern Rockies will begin to enter their peaks.

“Above Normal significant large fire potential is expected in the areas shown on the maps due primarily to increasing drought conditions, early loss of mountain snowpack, anticipated lightning activity, and overall hot and dry conditions that should persist through August. As is typically the case, the peak season fire activity across the northwestern portion of the country should diminish by mid-September as the seasonal transition begins and allows for wet fronts to bring precipitation to impacted areas.”