Hazy skies and light to moderate smoke expected to continue this weekend

 The conditions that much of eastern Colorado and the Front Range has seen over the last several days is likely to persist, at least through the coming weekend and into early next week. A stubborn ridging pattern is in place over the southwestern U.S. and does not look like it wants to budge for the time being. This means that the clockwise flow at upper levels of the atmosphere will likely continue to carry smoke from fires burning in other states in the general direction of Colorado.

NAM forecasted 600 mb winds at 18 UTC (12 pm MDT) on Sunday October 13, 2024, from weathernerds.com, shows a pattern that will likely continue to move smoke from out-of-state fires into Colorado over the next several days. 

What this means for us here in Colorado is that a persistence forecast will take us through the weekend. The haze that has lingered over the last few days and the up-and-down concentrations of fine particulates seen across the eastern slope of Colorado will likely continue, keeping particle pollution in the Moderate AQI category through at least Monday.

We favor these conditions over those experienced by folks who are closer to the fires and receiving much larger amounts of smoke, however we would also welcome a shift in the pattern (or some snow!) that could bring some relief from the gunk that has loitered in our area for long enough.

Keep on taking it easy if you are sensitive to smoke, keep an eye on air quality in your area, and we will keep you informed on any changes in this situation... hopefully sooner rather than later!

Intermittent plumes of smoke moving through the Front Range Wednesday afternoon

 As we had expected, smoke that is aloft in the atmosphere and was headed our way this morning is finding its way to the surface in areas of Colorado. In this scenario, the vertical mixing of the atmosphere is both hurting and helping us.

The low-level turbulence caused by warming daytime temperatures and our abundant Colorado sunshine, and its contrast with the relatively cooler air above the surface, is helping to draw smoke downward and is resulting in increases in particle pollution measured by surface monitors. Yet it is this same motion in the atmosphere that is creating a bank of cumulus clouds along the foothills. As the clouds move east off of the higher terrain, cooling is caused by cloud interactions with their surroundings, and helps to produce localized areas of sinking air that spreads out radially once it hits the ground. These areas of breezy outflow winds are helping to limit the overall impacts of the smoke, and are expected to help disperse surface concentrations as the afternoon progresses. Additionally, the clouds help to reduce the amount of surface heating, and decrease the vigor of up-and-down drafts, potentially limiting the amount of smoke that can be drawn down to surface level.

In addition to all of this, the dense plume of smoke that is the root of the issue continues to be fairly discrete, and is moving through the region... with emphasis on the word 'moving.'

Visible satellite image from CIRA shows the presence of smoke moving through the northern portions of Colorado, with cumulus clouds moving eastward off of the high terrain at 1:40 pm MDT on Wednesday afternoon. 

The overall take-away message is that we are seeing increases in particulate levels at several monitors throughout the region, but we expect those numbers to plateau and taper off as the day progresses. So while hazy skies and notable ups and downs in smoke levels are expected and taking place, we do not currently expect these conditions to persist for extended periods of time. 

As the fires continue to burn, additional plumes of smoke will be created and the potential for repetition of this cycle tomorrow does remain. Stay tuned for additional updates as we watch all of this unfold, and we will continue to share our thoughts and expectations.

Smoke will persist in areas of Colorado, with variable impacts throughout Wednesday

Smoke from out-of-state fires will continue to move into Colorado on Wednesday, mainly affecting eastern areas of the state. On Wednesday morning, surface concentrations remain in the Moderate range for many areas, with the highest numbers found on the plains and in the northeastern corner of Colorado. However higher concentrations are found in the Nebraska panhandle, and the first light images on satellite reveal the presence of smoke moving in from the northwest. The reason that the numbers shown on surface monitors do not match the location of smoke seen on satellite is because the smoke remains aloft, and has not reached the surface yet. As daytime mixing increases, we expect that smoke to be transported downward and an increase in monitored concentrations to be seen. Along with rising levels of fine particulates, degradation of visibility is also expected, causing hazy skies throughout many areas east of the Continental Divide.

The map of fine particulate concentrations from purpleair.com shows Good to Moderate impacts from wildfire smoke in areas of the Front Range, and in eastern and northeastern Colorado.

Smoke from fires in upwind states is seen in visible satellite imagery from CIRA as it is transported southward into Colorado from Wyoming (image from 8:20 am MDT on Wednesday, October 9, 2024).

Continued transport of smoke is expected throughout the day on Wednesday. While our primary area of focus for impacts from smoke is the areas on the eastern plains, similar conditions may be seen periodically along the Front Range as well. Though the surface levels may fluctuate throughout the day and affect different areas at different times, we expect Moderate conditions to be seen in widespread areas of Colorado, reaching levels that are Unhealthy for Sensitive Groups periodically.

The Air Quality Health Advisory for the eastern plains has been continued on Wednesday, and we encourage individuals who are sensitive to smoke to take health precautions to reduce exposure, and to reduce or avoid heavy exertion in all areas where smoke is present, especially areas currently under the Advisory.

As conditions continue to evolve, updates on observed impacts and future expectations will be posted.

Widespread wildfire smoke across eastern Colorado

Unfortunately many eastern Colorado residents are waking up to hazy skies Tuesday morning with plenty of wildfire smoke across the region.  Alerts and advisories remain in effect for that long stretch of Interstate 25 from Pueblo northward through Colorado Springs, Denver, Ft. Collins, and to the Wyoming state line.  The good news for these areas is that there should be some steady improvement throughout the day today.  Any improvement will be slower for areas further east on the plains.  Basically for areas east of the Interstate 25 corridor and north of Interstate 70, particle pollution will likely be elevated through tomorrow morning.  You can get all the details on advisories for your area at our website.  Additionally, you can keep track of air quality monitor readings at the EPA's Fire and Smoke Map and get helpful information to protect your health at CDPHE's wildfire smoke and health webpage.

Smoky sunrise over New Raymer.  Image courtesy of https://www.viaero.com/weather-cameras

Air Quality Health Advisories/Alerts posted for parts of eastern Colorado

 With wildfire smoke now increasing across eastern parts of Colorado, Air Quality Health Advisories/Alerts have been issued.  Although increased particle pollution is anticipated throughout most of eastern Colorado, the biggest concern in the short-term is along and near the Interstate 25 corridor from the Wyoming state line southward through Ft. Collins, Denver, Colorado Springs, and as far south as Pueblo.  Expect smoke to continue to increase across the region and likely linger through at least Tuesday morning.  At this point, we do think there will be some slow improvement Tuesday afternoon but some uncertainty does continue in the forecast.  Please stay tuned here for the very latest information as the situation continues to evolve.

Smoke on the horizon looking northeast from Rocky Mountain Metro Airport in Broomfield. Image courtesy of the Federal Aviation Administration

Wildfire smoke headed towards northeastern Colorado

 As northerly winds spread across northeastern Colorado on Monday, wildfire smoke in Wyoming is poised to move in.  Expect particle pollution to increase throughout the region on Monday, with the areas in northeastern Colorado most impacted likely to be bounded by the Wyoming stateline to the north, the Nebraska and Kansas statelines to the east, Interstate 70 to the south, and the foothills to the west.  This will result in many towns/cities being impacted by worsening air quality on Monday, including Sterling, Ft. Morgan, Greeley, Ft. Collins, Boulder, and Denver.  Please visit CDPHE's wildfire smoke and health page for more information on how you can protect your health.

Visible satellite image Monday morning of heavy smoke in southeastern Wyoming

The biggest area of concern will be areas along the Interstate 25 urban corridor from Denver northward to Wyoming, along with the foothills just to the west of this stretch of Interstate 25.  This is where we could see longer duration, higher concentration smoke that could last from late Monday afternoon into Tuesday.  Advisories/Action Day Alerts may be required for this area, so please remain updated with the latest information on CDPHE's advisory webpage. 

Air Quality Health Advisory issued for parts of western Colorado

 Hazy skies and elevated particle pollution are greeting folks on the West Slope Monday morning.  An Air Quality Health Advisory for Wildfire Smoke has been issued for Mesa, Delta, and Montrose Counties.  With that in mind, we ask residents in these counties (particularly in valley locations, including Grand Junction, Delta, and Montrose) to take it slow this morning.  The good news is that as the atmosphere heats up this afternoon, we are anticipating surface smoke concentrations to decrease which will result in an improvement in air quality.

A hazy sunrise over Grand Junction.  Image courtesy of the Federal Aviation Administration

  

Three large wildfires upwind of us are the main cause of smoke this weekend: the Yellow Lake Fire in Utah, and the Pack Trail Fire and Fish Creek Fire in Wyoming. Particulate Matter concentrations are Moderate at almost every location in Colorado. 

Today, the heaviest smoke is expected on the Western Slope, especially along the I-70 corridor. Grand Junction, Palisade, Delta, Montrose, Rifle, Glenwood Springs, and Aspen will likely see the worst of it. Expect lingering smoke overnight Sunday night into Monday on the western slope. 

As for eastern Colorado, the HRRR-Smoke model forecasts widespread smoke moving in on Monday. The smoke is expected to move in from Wyoming Monday morning, pushing south through the day on Monday and overnight into Tuesday.

For information on how to protect your health during a wildfire, visit our website.

Satellite imagery shows smoke (in gray) visible over Utah, Colorado, and Wyoming.

The HRRR-Smoke model's near-surface smoke product shows smoke pushing through eastern Colorado on Monday.

Smoke and Red Flag Conditions Today

We know what you're thinking - "Shouldn't fire season be over by now?" Sure, October is a little late for all this smoke and heat. While we wait for Autumn to get its act together, let's dig into today's smoke situation.

First, Smoke from the Yellow Lake Fire in Utah has moved into Western Colorado. Purple Air sensors show elevated particulate matter concentrations in Meeker, Rifle, Glenwood Springs, and Aspen. Satellite imagery shows smoke over Rio Blanco, Garfield, Mesa, Pitkin, Delta, and Gunnison counties. In these locations, you might consider limiting exercise, staying indoors, and closing your windows to reduce how much smoke you're breathing in. Additionally, you can find more tips on our website to protect your health from smoke.

Second, on the Front Range, the air is comparatively clearer, but, light smoke still lingers. Fires are still burning in Wyoming, and that smoke is still moving into Colorado. Particulate matter is expected to be in the Good to Moderate range today in Fort Collins, Greeley, Denver, and Colorado Springs.

Finally, hot, windy, and dry conditions are on tap today for a large section of Colorado. Several counties- primarily in northeast Colorado- are under a Red Flag Warning until 7 pm Saturday evening. Any new fires that spark may spread rapidly. 

CDPHE is monitoring the situation and will provide updates as necessary. 

Smoke (in gray) is visible in eastern Utah and western Colorado. The eastern plains, in comparison, are much cleaner.

Outlook for the weekend brings uncertainty and conflicting expectations, in regard to smoke in Colorado

 As is often the case in Colorado, especially during the ups-and-downs that come with fall weather in our state, the weekend ahead offers a mixed bag of pros and cons with regard to smoke. Smoke and fire models have been somewhat overplaying fire activity, but also mildly underestimating particulate concentrations; making it difficult to put too much confidence in the results that they produce. 

Weather models have a bit more agreement in terms of wind and temperature patterns, however that too ushers conflicting expectations. Saturday looks to have above average temperatures, low humidity, and breezy to gusty winds. These conditions heighten concerns for fire danger. This may not mean too much in Colorado due to the pleasant lack of fire activity in our state (barring any new starts, of course). Yet the same conditions are likely to affect neighboring states like Wyoming and Utah, so the same breezy winds and good atmospheric mixing that may help to decrease the smoke that is currently lingering in pocketed areas along the Front Range may also usher in smoke from those fires that are active elsewhere, upwind from us.

A cool front looks to arrive late on Saturday and may help to lower temperatures a bit, however it will also limit vertical mixing and decrease the dispersion of any lingering smoke from transport on Saturday. Gradual warming on Monday and Tuesday will be caused by the persistence of a ridging pattern in the southwest U.S., yet may also be conducive to continued transport of smoke into our region.

The good news in all of this is that the overall concentrations of fine particulates have remained in the Good or low-Moderate range of the AQI scale, and appear to persist in a similar fashion. The takeaway message here is that while we cannot rule out some influence of smoke on our air quality, no significant impacts are expected. 

Though pockets of low-moderate concentrations of fine particulates linger, and may persist during the coming weekend, the map of surface air quality due to particulates (smoke) from fire.airnow.gov shows mainly good air quality in Colorado.

As always, we will keep an eye on things and put forth any pertinent information that arises.

Smoke lingering in Colorado, overall improvement expected

The smoke that was expected to move into Colorado from the north on Wednesday moved further to the east and dispersed along the cold front that is heading our way. This spared many areas of Colorado from the higher particulate levels that appeared possible in yesterdays forecast. Great news! 

As the cold front enters Colorado from the northeast, it may push some of the smoke back toward our state and bring hazy skies and light concentrations of smoke to areas of eastern Colorado, pushing southward over the eastern plains throughout the day on Thursday.

Smoke from fires in western Wyoming made its way into areas of northwestern Colorado, and appears to be lingering in some of the mountain valleys in Routt, Grand, Moffat, Rio Blanco, and other northwestern counties. However, surface monitors still show minimal surface impacts, even in these areas.

The map of surface air quality due to fine particulate matter (smoke) from fire.airnow.gov in the morning hours of Thursday, October 3rd, shows only light to moderate impacts from smoke, due to wildfires actively burning in other states to the north and west of Colorado.

Breezy winds throughout he day on Thursday will help to disperse the smoke that is present and limit overall concentrations from rising significantly from the current levels. Additionally, as the trough associated with the cold front moves eastward, a shift in the large-scale wind pattern looks to push things northward again, and decrease the likelihood of more smoke coming our way on Friday and into the weekend.

Though haze and light concentrations of fine particulates are expected to persist, particularly in the areas mentioned above (with some pockets of Moderate air quality remaining possible too), no significant impacts are anticipated; and the trend appears to be headed in the right direction. We will keep monitoring conditions and updating expectations as things develop, however the current outlook lets us anticipate clearing skies and fresh autumn air in the coming days.

Those that are particularly sensitive to particulate pollution may continue to consider reducing activity on Thursday, especially folks with preexisting respiratory ailments. Yet the potential for worsening conditions appears to have been avoided, and continuing improvement is expected. More info will be reported here if things change from the current outlook, but we hope that, as the old saying goes, 'no news is good news,' over the coming days.

Lingering Smoke With More to Come This Week

 Smoke is lingering on the Front Range this morning. Particulate matter concentrations are Moderate in Denver, Fort Collins, and Greeley. Fires continue to burn in Idaho, Utah, and Wyoming, and smoke could move into Colorado starting Wednesday afternoon.

A cold front is expected to move into Colorado on Wednesday evening, and smoke could arrive alongside it. According to the HRRR-smoke model, smoke may arrive beginning Wednesday afternoon. Counties along the Wyoming border could see smoke by late afternoon, and smoke will continue to push south Wednesday evening, and overnight into Thursday. Northern Colorado could wake up to noticeable haze and smoke on Thursday morning. Smoke may persist throughout the day on Thursday.

It's unclear exactly how much smoke will arrive, but what is clear is that northern Colorado is likely to experience the highest concentrations. Craig, Steamboat Springs, Walden, Fort Collins, Greeley, and Denver could all be impacted. If you are in these areas, you might consider limiting exercise, staying indoors, and keeping your windows shut to minimize your exposure to smoke.

We will update the blog on Thursday as conditions develop.

Visible satellite imagery shows smoke in Wyoming, that may move into Colorado Wednesday and Thursday.

Front Range smoke

 Yesterday's cold front has transported smoke into the Front Range region from wildfires in Wyoming.  In fact, it is a bit more smoke that we had originally anticipated as the fires were more active yesterday that expected.  Although fine particle levels are not quite high enough for any advisories, people who suffer from heart or lung ailments in Denver, Boulder, Longmont, and Ft. Collins may want to skip that outdoor exercise this morning.  Any improvement with the air quality today will likely be slow as atmospheric mixing will not be very good.

The EPA's Fire and Smoke Map shows moderate (yellow) levels of particle pollution at air sensors throughout the Front Range region