Wildfire potential, February through May

Above: wildfire potential for February, 2018, issued February 1, 2018.

(Originally published at 1:41 p.m. MDT February 1, 2018)

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

If the prediction is accurate, the wildfire potential in Southern California and the Southern Plains will remain above normal for the entire four-month period and will increase in the Southwest and Northwestern Great Plains in Montana and North Dakota. The Eastern U.S. should expect normal or below normal potential.

Below are:

  • The highlights of the NIFC narrative report for the next several months;
  • NIFC’s monthly graphical outlooks;
  • NOAA’s three-month temperature and precipitation forecasts; and
  • Drought Monitor.

“The significant wildland fire potential forecasts included in this outlook represent the cumulative forecasts of the ten Geographic Area Predictive Services units and the National Predictive Services unit.

“Wildfire activity is likely to begin to increase in February as would be seasonally expected. During the early portions of the year it is typical for significant fires to begin to occur across the southern tier of the U.S. Currently it appears the highest likelihood for above normal significant wildland fire potential will be in place across portion of the southern plains and Florida and Georgia. Across the southern plains the last years precipitation totals have brought about a somewhat robust fine fuel crop, which will provide an elevated baseline of fire activity. When this elevated fuel condition is exacerbated by a period of dry and windy conditions it will provide opportunities for any ignitions to become significant fires.

“These incidents will be difficult to predict, but extra attention should be paid to this area when dry and windy conditions are forecasted. In Florida and Georgia the significant drought that led to amplified fire activity in the fall across the south has not improved. Moisture deficits in these fuel types are significant because they not only make ignition significantly more likely but they also make fires much more difficult to fight. Both conditions make the need for fire suppression resources higher. Both of these significant areas of above normal potential are likely continue through March and probably return to normal in April or May.

“At the end of the Outlook period significant fire potential across portions of Alaska will being to increase. This is also generally seasonally anticipated, however, the potential for above normal significant fire activity in the south central portion of the state is likely. Drought conditions indicate that some unusual dryness will be in place in this area as fire season begins. This will likely lead to earlier than usual ignitions and the potential for worse than usual fires. In the shorter term Hawaii is likely to see some elevated activity thanks to some unusual dryness, but this condition is expected to be short lived.

“Additionally, fire activity is expected to be below normal across western portions of Tennessee and Kentucky throughout the Outlook period.”

wildfire potential March

wildfire potential April May

3-month temperature precipitation outlook

drought monitor
Drought Monitor

Revised National Fire Danger Rating System approaches rollout

In this video Dr. Matt Jolly talks about his current project — the first revision of the U.S. National Fire Danger Rating System in 40 years.

After I ran across the video above which mentions the revision of the National Fire Danger Rating System, it made me wonder about the status of the project.

The system tracks weather events through their effects on live and dead fuels and adjusts them accordingly based on forecasted weather. The most visible product, which is used by most large land management agencies in the United States, is the predicted fire danger, often expressed as adjectives ranging from Low to Extreme. (The system used in Australia has those five categories plus one more — “catastrophic” or “code red”.)fire danger rating

The NFDRS was first released for general use in 1972 and was revised in 1978 and 1988. Work on another revision began in 2000 and was last scheduled for completion in 2017. Reportedly this latest version is much simpler and more automated than its predecessors and represents a vast improvement in fire potential assessment capabilities.

Jon Wallace, a member of the team revising the system, said that in tests last year they discovered a flaw in the Nelson model which had been in use for several years that needed to be corrected. And, rounding methods and decimal points in Firefamily Plus and WIMS did not match.

National Fire Danger Rating System 2016

The team feels that all of the hidden issues and bugs have been squashed and rollout plans are being finalized. The U.S. Forest Service has released their plan, and Mr. Wallace will present one to the National Wildfire Coordinating Group the week of January 22.

Pyrocumulonimbus clouds

Above: Bureau of Meteorology, Australia

(Originally published at 11:38 a.m. MST January 11, 2017)

The Australian Government’s Bureau of Meteorology has an excellent article about clouds that can form over rapidly burning vegetation fires. Pyrocumulus clouds can develop into pyrocumulonimbus that can generate lightning miles away from the fire.  Below are excerpts from the article.

What are pyrocumulonimbus clouds?

They’re a thunderstorm that forms in the smoke plume of a fire (or nuclear bomb blast, or volcanic ash cloud). In Australia they most commonly form in large and intense bushfire smoke plumes. (The official name for clouds that form this way is ‘flammagenitus‘, but they’re commonly known as pyrocumulonimbus.)

How do they form?

The intense heat from the fire causes air to rise rapidly in the smoke plume. The rising hot air is turbulent and draws in cooler air from outside the plume, which helps cool the plume as it rises. As the plume rises to higher and higher elevations the atmospheric pressure reduces, causing the plume air to expand and cool even further. If it cools enough, the moisture in the plume air will condense and forms cumulus cloud, which, because it comes from the fire plume, we call ‘pyrocumulus’. The condensation process causes latent heat to be released, which makes the cloud warmer and more buoyant and causes the cloud air to accelerate upwards. Further expansion and cooling causes more moisture to condense and the cloud air to accelerate upwards even more. In the right conditions the cloud can accelerate into the lower stratosphere before losing buoyancy. Collisions of ice particles in the very cold upper parts of these clouds cause a build-up of electrical charge, which is released by giant sparks—lightning. Having produced a thunderstorm, the cloud is now known as ‘pyrocumulonimbus’.

Wildfire potential, January through April

Above: wildfire potential for January, 2018.

(Originally published at 12:55 p.m. MDT January 2, 2018)

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

If the prediction is accurate, Southern California should see higher than normal wildfire activity throughout the period, with increasing potential in the southwest and southern great plains. The forecast for the southeast is for normal to below normal activity.

Below are:

  • The highlights of the NIFC narrative report for the next several months;
  • NIFC’s monthly graphical outlooks;
  • NOAA’s three-month temperature and precipitation forecasts; and
  • Drought Monitor.

“…Looking forward, a less amplified pattern is expected to develop for January and February with the mean position of the high pressure ridge being along or just off the West Coast. This should result in overall slightly colder than average conditions in northern areas with pockets of above average precipitation over the Northwest and Great Lakes regions. There is some concern that an active, westerly flow could produce overall warmer and drier than average conditions in March and April in these areas. Across the southern tier of the country, the overall warmer and drier than average conditions will continue through February and into March and possibly April. For this outlook period, the areas of note for increased fire potential will remain Southern California and the southwest. The Great Plains could see periodic increases in activity when wind events arise.”

Wildfire potential February Wildfire potential March Apriltemperature forecastprecipitation forecast

Drought Monitor
Drought Monitor

Fuels and fire behavior advisory issued for Southern California

The lack of precipitation this fall, along with a prolonged period of warm, dry, and occasional windy weather has caused fuels to be extremely dry across portions of Southern and Central California.

Welcome to what may become the new normal — for a Fuels and Fire Behavior Advisory to be issued for an area in the Western United States hours before New Years Eve. The Predictive Services office in the Southern California Geographic Coordination Center issued one on Friday for the following areas:

  • Southern Sierra
  • Central Coast Interio
  • Central Coast
  • South Coast
  • Western Mountain
  • Eastern Mountain, and,
  • Southern Mountains

A similar Advisory that was issued two weeks ago reached its expiration date so it was reupped for another 14 days.


Strong winds and extreme wildfire danger predicted for Southern California this week

This Santa Ana wind event will likely be the strongest and longest duration one we have seen so far this fire season. Red Flag Warnings have been issued for Sunday night through Thursday.

Above: Red Flag Warnings issued for Southern California December 3, 2017.

(Originally published at 9:31 a.m. PST December 3, 2017)

The strongest Santa Ana wind event so far this fire season is in the forecast for the coastal and mountain areas of Southern California this week. The National Weather Service has issued Red Flag Warnings for Sunday night through Thursday for areas within the counties of Santa Barbara, San Bernardino, Riverside, and San Diego.

It is unusual for a Red Flag Warning to extend over parts of five days. And this one has the possibility of being extended for an additional one or two days into the weekend.

The exact timing and speeds will vary by location, but generally, powerful winds will begin Sunday night out of the north and on Monday will be from the northeast at 25 to 40 mph with gusts of 50 to 65, reaching 80 at some peaks and exposed areas.

The NWS forecast includes this statement:

If fire ignition occurs, there will be the potential for rapid spread of wildfire with extreme fire behavior that could lead to a threat to life and property.

The strong winds and low relative humidities (5 to 15 percent)  should continue at least through Thursday. Long range computer models are showing the possibility that the Santa Ana winds could persist into Friday or Saturday, which may require the extension of the Red Flag Warnings.

Wind Gusts Tuesday california santa winds wildfire