09/25/2023 Forecast Update

FORECAST SUMMARY: Monday, September 25, 2023, through Friday, September 29, 2023

Ozone: 8-hour average Ozone concentrations remain Good through the forecast period.

PM-2.5: 24-hour average Fine Particulate levels will range between Good and Moderate.

FORECAST DISCUSSION: Two systems will influence weather conditions this week. High pressure to our northeast keeps dry conditions further north while a slow-moving low-pressure area traveling from Minnesota Monday to southwest Michigan early Thursday produces a cool, showery pattern for most of the lower peninsula. High temperatures through the period will range mostly in the middle and upper 60s with an east/southeasterly wind flow in place.

While not as prevalent as this past summer, wildfires persist in Quebec and Ontario, Canada. Looking back to Sunday, smoke over the region did produce low Moderate PM2.5 across some northern and central monitors. Satellite imagery Monday morning shows a smoke plume dropping southwest towards the upper Great Lakes region. The smoke plume moving towards northern locations may allow for Moderate PM2.5 through Wednesday. We do not anticipate daily averages of PM2.5 to reach higher than Moderate, but this is something we will monitor, and the forecast will be updated if conditions worsen. Overall, daily averages of PM2.5 levels should range between middle Good and middle Moderate this week.

On Thursday, some showers linger in southern areas, but high pressure becomes more dominant for the end of the week. Winds become more southerly and warmer/dry conditions are anticipated. Moderate PM2.5 may persist in the south, but smoke plume models show any lingering plumes pushing north of the area. Concentrations of PM2.5 should end the forecast period in the Good to low Moderate range.

Cooler temperatures, precipitation across much of the state, and a lower sun angle this time of year should keep ozone Good through the week.

EXTENDED FORECAST: Extended models show dry weather and warmer conditions for the coming weekend. Pollution levels may increase towards Moderate late in the forecast period.

Next Forecast Update: Friday, September 29, 2023

09/22/2023 Forecast Update

FORECAST SUMMARY: Friday September 22nd, 2023, through Monday September 25th 2023

Ozone: Ozone concentrations are expected to be in the Good to Moderate range.

PM-2.5: PM-2.5 concentrations are expected to be in the Good to low-Moderate range.

FORECAST DISCUSSION: After a week of relatively picturesque weather conditions, we can expect much of the same for this picture-perfect weekend ahead for us Michiganders. High-pressure is still dominating the area with the High-pressure system sitting over central Ontario currently and is expected to stay there through the weekend. This will result in winds being predominantly easterly with some northerly component shifting the direction throughout the weekend. A warming pattern that we saw to end the work week continues into the weekend with surface temperatures well into the 70s for much of Michigan and the region.

For air quality, relatively light surface winds in the morning hours may result in PM-2.5 concentrations to build up in more populated areas. Per usual, as the day carries on, and winds increase, those concentration will decrease. Ozone will not have the required ingredients to produce high concentrations. There may be Moderate Ozone sprinkled across the state, which was seen this past week, but nothing over mid-Moderate should be expected.

EXTENDED FORECAST: The current weather pattern looks to continue into next week, with cooler temperatures expected. Overall air quality is expected to remain Good.

Next Forecast Update: Monday September 25th, 2023

09/18/2023 Forecast Update

FORECAST SUMMARY: Monday September 18th, through Friday September 22nd, 2023

Ozone: Ozone concentrations are expected to be in the Good to Moderate range.

PM-2.5: PM-2.5 concentrations are expected to be in the Good to low-Moderate range.

FORECAST DISCUSSION: As this past weekend most definitely felt like Fall, we see a gradual warmup throughout this week for the majority of Michigan. We start off the week with two High-pressure systems dominating the region and look to hang around through the end of the work week. Surface winds look to be predominantly southerly with slight variations in the easterly and westerly direction throughout the week. These southerly winds are the reason for surface temperatures approaching, and even eclipsing, 80 degrees towards the end of the work week. Also thanks to the High-pressure systems, every day will see a fair amount of sunshine. As we approach the weekend, the High-pressures start to move off the east with a building low-pressure system setting up over the Great Plains, which will influence our weather towards the end of the weekend.

 In terms of air quality, PM-2.5 continues to be a non-issue compared to what was seen earlier in the summer. Southerly winds this week will also help keep any residual Canadian wildfire smoke to our north, hence why the PM-2.5 forecast is Good to low-Moderate. However, due to the High-pressure we will see this week, early morning stagnation could be possible in more populated areas due to morning commutes and low winds. For Ozone, we expect overall Good concentrations for this week mainly due to cooler temperatures than what produces high concentrations of Ozone and the fact of days becoming shorter and less overall energy coming from the sun. Although, with winds periodically being southwesterly in the latter half of the week, there may be some low-end Moderate Ozone concentrations more so towards west and southwest Michigan.

EXTENDED FORECAST: A change in airmass is expected towards the end of the weekend which will help clean out any buildup from the High-pressures this week. Overall air quality is expected to be Good.

Next Forecast Update: Friday, September 22, 2023

09/15/2023 Forecast Update

FORECAST SUMMARY: Friday, September 15, 2023, through Monday, September 18, 2023

Ozone: 8-hour average Ozone concentrations will remain generally Good with only a few Moderates possible.

PM-2.5: 24-hour average Fine Particulate levels are expected to range between Good to Moderate.

FORECAST DISCUSSION: This forecast period features a frontal boundary moving northwest to southeast through the state between Friday and Sunday. Precipitation chances begin Friday across the Upper Peninsula while generally sunny, dry conditions are seen across the Lower Peninsula. Clouds increase late Friday into Saturday in the south as the boundary sinks southeast and precipitation comes in the forecast. Precipitation may linger in the south Sunday; however, dryer weather moves in late as high pressure settles in from the northwest.

Wildfires persist far to our northwest in Canada and smoke models show a plume sinking in from the northwest behind the weekend front. The smoke plume does not look dense enough to cause significant increases in PM2.5 concentrations, but readings in the upper Good to low Moderate range are possible. We will keep a Moderate forecast Saturday and Sunday as a conservative measure, and levels by Monday are anticipated to fall back into the Good range.

Sunny skies and southwesterly winds in the south Friday are typically conducive for ozone development, but cooler temperatures and less daylight this time of year help keep levels generally Good. Increased clouds and precipitation chances Saturday into Sunday allow for Good readings to continue. Conditions dry out for the start of the new work week, but Good ozone persists thanks to cooler temperatures from northerly winds. 

EXTENDED FORECAST: Extended models show dry weather through midweek with warming temperatures during the period. If this forecast remains on track, pollution levels may increase into the low Moderate range.

Next Forecast Update: Monday, September 18, 2023

09/11/2023 Forecast Update

FORECAST SUMMARY: Monday, September 11, 2023, through Friday, September 15, 2023

Ozone: 8-hour average Ozone concentrations will remain Good through Thursday with scattered Moderates possible Friday

PM-2.5: 24-hour average Fine Particulate levels are expected to be mostly Good with only a few low Moderate readings possible.

FORECAST DISCUSSION:The start of this forecast period favors clouds and rain as a low-pressure area and associated boundary pass through the state. Upper-level energy and cooler temperatures keep rain around Tuesday, but precipitation will be more scattered in nature. High pressure moves in from the west Wednesday drying conditions out and clearing skies. The coolest temperatures are projected Wednesday into Thursday morning with the center of the high overhead. Highs Wednesday struggle to reach out of the 50s across the northern portion of the state; further south readings in the low-middle 60s are expected. Thursday morning lows dip down into the 30s across the north with 40s elsewhere.

Regarding ozone this week, clouds Monday and Tuesday, northerly winds late Monday through Thursday, and cooler conditions hamper ozone development keeping readings Good. The high-pressure area tracks east of the state Friday, and southerly winds bring warmer temperatures back into the region. Plenty of sunshine is anticipated as well, and the combination of sunshine and warmer air may lead to increases in ozone. However, considering the time of year a significant development is not expected and ozone concentrations should not reach higher than low-Moderate in southern and/or western locations.

Wildfire smoke models are not showing any substantial plumes the next few days; therefore, we do not expect wildfire smoke to influence PM2.5 conditions this week. Our expectation for PM2.5 is that increased moisture Monday into Tuesday may allow for low Moderate readings, generally across the southern portion of the state, otherwise, Good levels are expected. Light winds Wednesday and Thursday morning may allow for hourly concentrations in the Moderate range during the morning hours, but increases should mix out and decrease during the day allowing for 24-hour averages to be mostly Good. Southerly winds developing Friday may bring in some scattered low Moderate readings across the southern portion of the state.

EXTENDED FORECAST: Extended models show a continuation of dry conditions and warmer temperatures for the start of the weekend. Pollution levels may reach low Moderate during this period.

Next Forecast Update: Friday, September 15, 2023

09/08/2023 Forecast Update

FORECAST SUMMARY: Friday, September 8, 2023, through Monday, September 11, 2023

Ozone: 8-hour average ozone concentrations are expected to be Good.

PM-2.5: 24-hour average Fine Particulate concentrations are also expected to be Good to Moderate

FORECAST DISCUSSION: The cloudy, drab weather that has been with us since midweek will finally start to give way as the current slow moving low-pressure system finally begins exiting the region.  The good news is that Air Quality is currently Good with all pollutant levels very low.

Low level moisture will persist through much of Friday providing clouds and the occasional sprinkle.  Light north to northeast wind will prevail into Saturday as Canadian high pressure builds into the western Great Lakes.  Incoming dryer air will chase away the cloud cover providing sunny skies through Saturday and Sunday with cool temperatures in the lower 70’s.

The smoke we were watching over the Plaines states during the week remained in that region and never threatened Michigan.  Computer models have that smoke breaking up over the next few days and we may see some light residuals of that smoke but no worse than Low Moderate.

The next low pressure is currently predicted to arrive during Monday bring a good chance of rain and cooler temperatures during the first half of next week.

EXTENDED FORECAST: Air Quality should be generally Good to start the next work week.

Next Forecast Update: Monday, September 11, 2023

09/05/2023 Forecast Update

FORECAST SUMMARY: Tuesday, September 5, 2023, through Friday, September 8, 2023

Ozone: 8-hour average ozone concentrations are expected to be Good to Low Moderate.

PM-2.5: 24-hour average Fine Particulate concentrations are also expected to be Good to Low Moderate

FORECAST DISCUSSION: Tuesday may well be the last hot and humid day for summer 2023. Temperatures are expected to top out in the low 90’s in the southern half of the state with dew points in the mid-60’s.  With that level of temperature and humidity, it is possible to see popup thunderstorms during the afternoon.  A slow-moving front will bring an end to this episode of hot and humid weather during Wednesday and Thursday along a decent dose of precipitation.  Following the frontal passage, temperatures by the end of the week and into the weekend should be in the lower 70-degree range with mostly dry conditions.

The heat and humidity of the holiday weekend brought concerns about potentially elevated ozone, especially along the western lake shore counties.  While we did see numbers in that area reach the mid to upper 60 ppb range, we fortunately did not see any USG values.

As has been the pattern for most of this summer, Air Quality concerns have bounced between ozone problems and smoke problems, with occasional episodes where both have simultaneously been a problem.  As we get past the high ozone potential during the holiday weekend, we now look to smoke issues currently in the Plaines states.  A series of wildfires in the North Dakota and Montana are combining with nearby wildfires in Canada to present smoke problems in that area.  Fortunately, all the smoke models are in good agreement that for the next few days, the smoke should get no closer than western Minnesota and Iowa. 

As our ozone season winds down with shorter, cooler days, fine particulates in smoke are not limited by temperature, solar intensity, or season.  As such, we will keep a close eye on the smoke out west.  As that smoke currently does not look to travel this far east, I do not see a need to update this forecast before our regular weekend forecast update posted on Friday.

EXTENDED FORECAST: Air Quality should be generally Good to Moderate through the weekend.

Next Forecast Update: Friday, September 8, 2023

09/04/2023 Forecast Update

FORECAST SUMMARY: Monday, September 4, 2023, through Tuesday, September 5, 2023

Ozone: 8-hour average Ozone concentrations are forecast to range between Good and Moderate; with isolated USG levels possible.

PM-2.5: 24-hour average Fine Particulate levels are expected to be in the Good to Moderate range.

FORECAST DISCUSSION: This Labor Day features sunshine and warm temperatures into the 90s. By Tuesday, dew points increase ahead of an approaching system. Warm and muggy conditions will be in place, however, more prevalent cloud cover and small chances for storm development keep ozone from significantly increasing. Ozone concentrations Sunday ranged upper Good to upper Moderate, and as expected, highest readings were in west Michigan along the lakeshore. Hourly concentrations Monday morning at western locations were running lower than they were this time yesterday, but since Sunday’s max 8-hour levels were close to USG, we decided to increase the forecast from Moderate to USG for our Grand Rapids forecast area for Monday; this forecast area includes the lakeshore areas from Muskegon to Holland. Across the rest of the state Moderate readings are anticipated. With increased clouds and precipitation chances, Good to Moderate ozone is to be expected Tuesday.

Regarding PM2.5, smoke models show any plumes staying north and west of the region the next few days. Hourly concentrations at some locations were ranging low Moderate Monday morning. Increased wind speeds should keep readings from climbing much through Tuesday; daily average PM2.5 concentrations should remain upper Good to low Moderate.

EXTENDED FORECAST: Extended models continue showing a pattern change mid-week with chances for precipitation and cooler conditions. Pollution levels will be mostly Good during this period.

Next Forecast Update: Tuesday, September 5, 2023

09/03/2023 Forecast Update

FORECAST SUMMARY: Sunday, September 3, 2023, through Monday, September 4, 2023

Ozone: 8-hour average Ozone concentrations are forecast to range between Good and Moderate; with isolated USG possible.

PM-2.5: 24-hour average Fine Particulate levels are expected to be in the Good to Moderate range.

FORECAST DISCUSSION: Sunday features more sunshine than Saturday and temperatures start increasing as ridging builds in from the west. Dry conditions are expected, and gusty southerly winds develop over the region bringing in warmer, muggier conditions. This weather trend is forecast through the Labor Day holiday with highs in the 90s across much of the state.

While sunshine and warmer temperatures the next few days lead towards ozone conducive conditions, stronger winds look to hamper significant pollution development. Forecast ozone models show isolated USG levels along the west Michigan lakeshore due to influence from the lake, otherwise, concentrations remain Moderate. Based on weather maps and pollution trends, we agree with this evaluation. Isolated locations may reach USG, but mostly Moderate ozone is expected Sunday and Monday across the state. We will keep an eye on levels and if this changes, we will update the necessary area(s) to USG, triggering EnviroFlash notifications.

Regarding PM2.5, smoke models show any plumes staying north and west of the region over the next few days. Hourly concentrations across southern areas were ranging low Moderate Sunday morning. Increased wind speeds should keep readings from climbing much the next few days. Daily average PM2.5 concentrations should remain upper Good to low Moderate.

EXTENDED FORECAST: Extended models show a pattern change mid-week with chances for precipitation and cooler conditions. This will improve any pollution increases seen earlier in the week.

Next Forecast Update: Monday, September 4, 2023

09/02/2023 Forecast Update

FORECAST SUMMARY: Saturday, September 2, 2023, through Sunday, September 3, 2023

Ozone: 8-hour average Ozone concentrations are forecast to range between Good and Moderate; with isolated USG possible.

PM-2.5: 24-hour average Fine Particulate levels are also expected to be in the Good to Moderate range.

FORECAST DISCUSSION: Clouds and scattered precipitation move from north to south across the state today, Saturday, as a boundary sinks through. This system will keep air quality from reaching higher than Moderate for ozone while some low-Moderate PM2.5 is possible. The forecast is still on track for a warmup Sunday through the Labor Day holiday. High pressure dominates at the surface and an upper-level ridge builds over the area bringing in southerly winds and warm temperatures. Dew points also increase; therefore, conditions will feel muggier outside.

As for air quality, there is still some question on ozone levels Sunday. Models are keeping higher concentrations confined to the west Michigan lakeshore. While more sunshine is expected tomorrow compared to today, Saturday, forecast models are picking up on some clouds as well. One thing is still on track and that’s southerly winds at the surface and upper levels bringing in warmer temperatures. At this point, we feel widespread USG ozone is unlikely Sunday in the west, and an Action Day is not warranted. Based on forecast models, higher wind speeds also hamper significant ozone development helping keep ozone Moderate. Current pollution trends will be evaluated tomorrow morning and if this changes, the Moderate forecast will be updated to USG triggering EnviroFlash notifications.

There have been some increases in PM2.5 this morning into the low-Moderate range and we expect this trend to continue. Concentrations over the next few days should range from upper Good to low Moderate.

EXTENDED FORECAST: Extended models show a pattern change mid-week with chances for precipitation and cooler conditions. This will improve any pollution increases seen earlier in the week.

Next Forecast Update: Sunday, September 3, 2023

09/01/2023 Forecast Update

FORECAST SUMMARY: Friday, September 1, 2023, through Saturday, September 2, 2023

Ozone: 8-hour average Ozone concentrations are forecast to range between Good and Moderate.

PM-2.5: 24-hour average Fine Particulate levels are also expected to be in the Good to Moderate range.

FORECAST DISCUSSION: After the mid-week cooldown, temperatures will be on the rise as we move into the Labor Day weekend. Along with warmer temperatures, dry conditions are expected thanks to high pressure dominating. This set-up, however, brings with it the threat for increased ozone. On a positive note, southerly winds through the period should keep wildfire smoke plumes from coming into the region and influencing pollution levels.

High pressure east of Michigan is forecast to sink south over the weekend. This position gives us a southerly wind flow through the period which turns a bit more westerly Saturday as a weak/dry boundary moves in from the north. Warm temperatures west of us Friday move into the area during the weekend, increasing temperatures each day. Similar conditions are expected at upper levels with warm, southerly flow over the region.

For the ozone forecast, there is currently a low background in place and while readings are likely to increase Friday, 8-hour readings higher than low-Moderate are not anticipated. The boundary Saturday brings in a cloud layer which reduces chances for increased ozone. More widespread Moderate readings are forecast Saturday and there is a small chance a monitor may reach low-end USG, but this chance is low and would be isolated. Sunshine will be more prevalent on Sunday making it a better day for ozone conducive conditions. Because of this, there will be a forecast update Saturday morning to detail if conditions warrant an Action Day.

Like ozone, there is currently a low background of PM2.5 in place. Warmer conditions and southerly winds tend to increase PM2.5 levels, but stronger winds are forecast. Increased winds lead to more mixing that should keep PM2.5 readings Good to low-Moderate.

EXTENDED FORECAST: Extended models show warm, dry conditions lingering through the Labor Day holiday. With the threat for increased ozone continuing early next week, we will be doing daily updates to the air quality forecast until the threat ceases.

Next Forecast Update: Saturday, September 2, 2023

08/28/2023 Forecast Update

FORECAST SUMMARY: Monday, August 28, 2023, through Friday, September 1st, 2023

PM-2.5: PM-2.5 concentrations are expected to be in the Good to low-Moderate range.

OZONE: Ozone concentrations are expected to be in the Good range.

FORECAST DISCUSSION: The beautiful weekend spills over into the start of the work week with today, Monday, seeing clear, blue skies and temperatures in the low-to-mid 70s. Unfortunately, this is short-lived as a frontal boundary crosses over the state throughout the day on Tuesday; bringing cloudy skies and rain to most areas. However, we rebound rather quickly as Wednesday sees clear skies, but temperatures barely move out of the 60s due to northerly flow over the region. We slowly warm up on Thursday, as winds start to shift to more easterly flow as a High-pressure system sets up over the state. On Friday, winds shift to predominantly southerly, with some westerly component, which will bring in warmer temperatures into the 80s for most of Michigan.

In terms of air quality, due to unfavorable wind directions for Ozone development, it is not expected that Ozone will be an issue week. Also, with the cooler temperatures, Ozone will not have the proper ingredients to produce, even though there will be ample sunlight. There may be an hourly concentration, or two, in the Moderate range, but overall Ozone averages should be in the Good range. For PM-2.5, wildfire smoke is continually being monitored. For the coming days, it is not projected that wildfire smoke will cause PM-2.5 to rise higher than low-Moderate. In some smoke models, there appears to be some smoke coming down from Canada to our west over Minnesota, but the models appear to keep it west of us. As always, wildfire smoke and updated models will be monitored daily.

EXTENDED FORECAST: Going into the Labor Day holiday weekend, we see quite the warmup as winds shift to southwesterly flow, and a similar heat dome that we saw last week in the central part of the country looks to set up again. These warm temperatures and favorable winds may produce Ozone issues, but will be looked at more closely as the weekend gets closer.

Next Forecast Update: Friday, September 1st, 2023

08/25/2023 Forecast Update

FORECAST SUMMARY: Friday, August 25, 2023, through Monday, August 28, 2023

PM-2.5: 24-hour average Fine Particulate levels will range between Good and low Moderate.

OZONE: 8-hour average Ozone concentrations are expected to be mostly Good through the period.

FORECAST DISCUSSION: Hot, humid conditions ended Thursday evening as strong storms associated with a cold front moved through the southern portion of the state. Some areas are cleaning up Friday due to storm damage and several locations are without of power. Moisture lingering Friday keeps scattered light precipitation in the forecast under mostly clouds skies. Small chances for precipitation remain late Friday/early Saturday as another weaker boundary sinks through. High pressure moves in from the north Sunday, drying conditions and providing ample sunshine for the start of the new week.

While hourly ozone concentrations in the southwest reached USG for a short time Thursday afternoon clouds moved in hampering development keeping 8-hour concentrations Moderate. Ozone will not be an issue this weekend into early next week thanks to northerly winds and cooler temperatures in the 70s. Ozone concentrations through Monday should range mostly Good.

The southwest portion of the state also saw Moderate PM2.5 Thursday; however, readings Friday morning were running Good statewide. Northerly flow is expected through the period and wildfire smoke maps show only light smoke plumes over the region this weekend. We will keep an eye on this through the forecast period making updates, if necessary, but at this time smoke does not look to influence ground level PM2.5 and concentrations should range Good to low Moderate through early next week.

EXTENDED FORECAST: Extended models show the next chance for precipitation Tuesday as a cold front moves through the region. Behind that, a cool down is expected with highs only in the 60s by mid-week. Aside from possible small increases in pollution ahead of the boundary Tuesday, levels should generally be Good.

Next Forecast update: Monday, August 28, 2023

08/23/2023 Forecast Update (Copy)

FORECAST SUMMARY: Wednesday, August 23, 2023, through Friday, August 25, 2023

PM-2.5: 24-hour average Fine Particulate levels will range between Good and low Moderate.

OZONE: 8-hour average Ozone concentrations are expected to be Good to Moderate across much of the state, with USG possible in the southwest Wednesday and Thursday.

FORECAST DISCUSSION: As forecast, a complex of storms tracked from the Upper Peninsula southeast into central and southeastern areas Wednesday morning. As Wednesday progresses, a warm front pushes in from the west before stalling for a time across the central part of the state. Strong southerly winds develop south of this boundary bringing in very warm surface and upper-level temperatures and high dew points. This will cause hot, humid conditions to develop Wednesday afternoon into Thursday, especially across the southern portions of the state. The frontal boundary will also be the focus of storm development over the next two days. Temperature and humidity levels improve Friday as the boundary sinks south and northerly winds bring in cooler temperatures and lower dew points.

The threat for increased ozone remains Wednesday and continues into Thursday across the southwestern portions of Michigan. Because of this, we are continuing the current Air Quality Action Day through Thursday and forecasting ozone concentrations in the Unhealthy for Sensitive Groups (Orange AQI) range for the counties listed above. Along and north of the forementioned boundary, cloud cover and higher chances for storm development are expected. These conditions should keep ozone from reaching higher than Moderate, and possibly Good further north. Ozone concentrations improve with the airmass change and northerly winds Friday. Readings Friday should range between middle Good and low Moderate.

Wildfire smoke maps were reviewed and we do not expect wildfire smoke to have an influence on pollution levels the rest of the week. With southerly winds and increased moisture along and south of the boundary, PM2.5 is likely to increase, but readings higher than Moderate are not expected. Any increase in PM2.5 should improve to Good on Friday.

EXTENDED FORECAST: Extended models show another cold front passing late Friday/early Saturday bringing precipitation back into the forecast. Regardless on the exact timing of this boundary, cooler temperatures are expected during the upcoming weekend which should help keep pollution levels low. This forecast will be updated Friday to better detail the coming weekend into early next week.

Next Forecast update: Friday, August 25, 2023

08/22/2023 Forecast Update

FORECAST SUMMARY: Tuesday, August 22, 2023, through Wednesday, August 23, 2023

PM-2.5: 24-hour average Fine Particulate levels will range between middle Good and low Moderate.

OZONE: 8-hour average Ozone concentrations are expected to be Good to Moderate across much of the state, with USG possible in the southwest Wednesday.

FORECAST DISCUSSION: As expected, a complex of showers and storms is moving through the Upper Peninsula southeast towards the Detroit area Tuesday. This area keeps clouds and precipitation in the forecast for all but the southwest portion of the state. High pressure which has been dominating with a northeasterly flow the past two days tracks east Tuesday. As this happens, a frontal boundary to our south begins moving north towards the state. The easterly flow Tuesday switches to the south Wednesday ushering in warm/humid conditions, especially in the southwest. The frontal boundary is expected to stall across central lower Michigan into Thursday and associated moisture keeps showers and storms in the forecast across northern, central, and eastern locations.

Good to low Moderate ozone and PM2.5 levels can be expected Tuesday thanks to easterly winds and cooler surface and upper-level temperatures. Clouds and precipitation near and north of the frontal boundary Wednesday should keep ozone from reaching higher than Moderate, but models show less clouds in the southwest. More sunshine in the southwest along with southerly winds and increases in temperatures makes ozone conditions likely. Forecast models seem to align with our thoughts, picking up on this ozone increase as well. To cover the threat for ozone in the Unhealthy for Sensitive Groups (Orange AQI) range, we have issued an Air Quality Action Day on Wednesday for the southwestern counties listed above. The threat for increased ozone looks to continue Thursday so we will evaluate current trends and weather maps Wednesday morning to determine if the Action Day will be continued and/or expanded Thursday.

Wildfire smoke maps were reviewed and there is still a light plume lingering over the region, but PM2.5 levels have improved to mostly Good early Tuesday. We do not expect wildfire smoke to be a large influence in pollution levels this week, however, increases of PM2.5 into the Moderate range can be expected in central and southern areas with the southerly flow, humid conditions, and pooling that typically happens along frontal boundaries.

EXTENDED FORECAST: The warm-up Wednesday and Thursday may be short-lived due to a cold front expected to pass through late in the week. If this pans out, the threat for increased ozone should come to an end Friday.

Next Forecast update: Wednesday, August 23, 2023

08/21/2023 Forecast Update

FORECAST SUMMARY: Monday, August 21, 2023, through Tuesday, August 22, 2023

PM-2.5: 24-hour average Fine Particulate levels will range between upper Good and low Moderate.

OZONE: 8-hour average Ozone concentrations are expected to be Good to Moderate.

FORECAST DISCUSSION: A weak cold front moved through late Sunday/early Monday bringing in northeasterly winds and less humid conditions. Monday will feel more comfortable than Sunday with lower dew points and temperatures in the upper 70s to low 80s. A switch back is in store, however, as heat and humidity build to our west Monday and Tuesday. Surface high pressure north of the state tracks east, as a boundary lifts north Wednesday. This changes winds back to a southerly direction by mid-week bringing the heat and humidity east and into Michigan. Overnight storms are also a possibility both Monday night into Tuesday morning, and more so Tuesday night into Wednesday morning. Current forest models show these systems missing the southwest portion of the state both periods, keeping conditions dry. 

High clouds and northeasterly/easterly winds through Tuesday should keep pollution levels in check with readings higher than Moderate not anticipated for either ozone or PM2.5. Southerly winds developing Wednesday, coupled with increases in both surface and upper-level temperatures, brings a threat for increased ozone. Ozone models are picking up on this as well, showing increases into the Unhealthy for Sensitive Groups range, mostly in the southwest, by Wednesday. A forecast update will be done Tuesday morning to evaluate updated models, and to determine if an Action Day for ozone will be necessary Wednesday.

Wildfire smoke maps were reviewed and there is still a plume lingering over the region. Thankfully, the smoke has for the most part remained at upper levels only resulting in small PM2.5 increases. Daily averages of PM2.5 were in the upper Good to low Moderate range this past weekend. Smoke models do show a bit of an improvement Tuesday, but the plume looks to linger, mostly at upper levels, this week. With smoke remaining overhead, PM2.5 should continue in the upper Good to low Moderate range. Along with ozone trends, we will be keeping an eye on smoke models and PM2.5 readings, making updates if necessary.

EXTENDED FORECAST: The warm-up Wednesday and Thursday may be short-lived due to a cold front expected to pass through late in the week. If this pans out, the threat for increased ozone should come to an end Friday.

Next Forecast update: Tuesday, August 22, 2023

08/18/2023 Forecast Update

FORECAST SUMMARY: Friday, August 18, 2023, through Monday, August 21, 2023

PM-2.5: 24-hour average Fine Particulate concentrations are also expected to be Good to Moderate.

OZONE: 8-hour average ozone concentrations are expected to be Good to Moderate.

FORECAST DISCUSSION:

Over the past few days, the smoke models have been painting an ugly picture of poor Air Quality over Minnesota and Wisconsin with Michigan eventually to follow.  Fortunately, the smoke has stayed aloft, and surface smoke has not gotten any worse than High Moderate on the western side of the Lake.  Even though one model continues to predict dire surface concentrations, the remaining models have backed off and are more in line with what we are actually seeing on the ground.  Those models are now predicting no worse than Moderate and that that will be pushed out in the next couple of days.  As such, the Michigan PM-2.5 AQI forecast will be kept in the Moderate range until it clears out.

Even though we are expecting a nice warmup over the weekend, ozone looks to behave.  Cooler Friday temperatures will give way to warmer 80-degree weather during Saturday and Sunday under clear skies.  One of the ozone models is showing an ozone buildup over the southern tip of Lake Michigan on Sunday, but it is standing alone in that prediction compared with other models.

At this point, it looks safe to continue this forecast through the weekend with Monday as the next update.  However, the conditions will be monitored over the weekend and if the smoke aloft starts mixing down over Michigan or ozone numbers start to creep up, the forecast will be updated as necessary.

EXTENDED FORECAST:

Air Quality should be generally Good to Moderate to start the next work week.

Next Forecast update: Monday, August 21st, 2023. Forecast updated by Jim Haywood

08/14/2023 Forecast Update

FORECAST SUMMARY: Monday, August 14, 2023, through Friday, August 18, 2023

PM-2.5: 24-hour average Fine Particulate concentrations are also expected to be Good to Moderate.

OZONE: 8-hour average ozone concentrations are expected to be Good with scattered Low Moderate.

FORECAST DISCUSSION:

A slow-moving low-pressure system will approach and pass through Michigan later Monday and into Monday night.  There is a good chance for significant precipitation as this system passes through and Air Quality is expected to be Good.  Some residual showers during Tuesday and a drying out during Wednesday with continued Good Air Quality are expected.

We will get into a southwesterly air flow pattern late Wednesday and into Thursday as another front approaches and passes through the region.  This will provide another precipitation event however probably not as widespread or heavy as anticipated for late Monday. 

Air Quality should remain mostly Good with scattered Low Moderates for the duration of the work week.  The long-range forecast has the weekend warming up with daily highs climbing back into the mid to upper 80’s.  While the days are getting noticeably shorter, we are still in the midst of ozone season and this forecast will be updated on Friday to provide the weekend outlook. 

Wildfires is still widespread in Canada.  Fortunately, projected wind patterns are not showing any significant amount traveling over the Midwest during this forecast period.

EXTENDED FORECAST:

Air Quality should be generally Good to start the weekend, but ozone concentrations are likely to increase during the course of the weekend.

Next Forecast update: Friday, August 18th, 2023. Forecast updated by Jim Haywood

08/11/2023 Forecast Update

FORECAST SUMMARY: Friday, August 11th, 2023, through Monday, August 14th, 2023

PM-2.5: PM-2.5 concentrations are expected to be in the Good to Moderate range.

OZONE: Ozone concentrations are expected to be in the Good to Moderate range.

FORECAST DISCUSSION:

The majority of Michigan wakes up to a beautiful morning on this Friday. However, it is short-lived as a weather system traverses the region this afternoon bringing cooler temperatures and rainy skies. Indeed, the work week ends, as the work week began—dreary. Although, as we get into Saturday morning, the precipitation clears to the east and clear skies return with surface temperatures in the upper-70s to low-80s, with WNW winds cooling down the temperatures. We are in this airflow until Monday when winds shift to more southerly flow due to yet another approaching frontal boundary.

In terms of air quality, due to the rain we are expecting later this afternoon, I do not expect Ozone to be an issue today and through the weekend. With winds shifting to more northerly Saturday and Sunday, and with temperatures barely reaching the 80s, Ozone will not have the proper ingredients to develop. Upper-level temperatures will be in the mid-to-upper teens Celsius however, but I do not expect those upper-level temperatures to initiate any USG Ozone development. For PM-2.5, there will be regional smoke hanging around through the weekend due to the ongoing Canadian wildfires. I do not expect PM-2.5 concentrations to reach anything higher than Moderate.

EXTENDED FORECAST:

Another system is expected to come through on Monday before exiting the area on Tuesday. This will help keep overall air quality Good.

Next Forecast update: Monday, August 14th, 2023. Forecast updated by Alec Knowacki.

08/07/2023 Forecast Update

FORECAST SUMMARY: Monday, August 7th, 2023, through Friday, August 11th, 2023

PM-2.5: PM-2.5 concentrations are expected to be in the Good to Moderate range.

OZONE: Ozone concentrations are expected to be in the Good to Moderate range.

FORECAST DISCUSSION:

The majority of Michigan wakes up to overcast skies and damp grass from overnight showers. The sun will begin to peak out later in the day and into tomorrow as the system that brought the rain leaves the region. A high-pressure system sets up to our northwest tomorrow which will provide sunny skies and surface temperatures in the low-80s. This weather pattern remains the same until Wednesday night into Thursday when a low-pressure system traverses the area, shifting us back into possible rainy conditions. Possible multiple rounds of on and off rain will be present until Friday and into Saturday.

In terms of air quality, wildfire smoke looks to remain out of the region for this week, so PM-2.5 concentrations will remain in the Good to Moderate range. For Ozone, multiple changes in airmass will keep the air clean of stagnation and a buildup of Ozone concentrations. The one day we will keep an eye on is Wednesday, which will have surface temperatures in the low-to-mid 80s and predominantly southwest winds. This may allow for Ozone to develop in the southwest Michigan area but is not expected to be widespread. The approaching system may increase clouds Wednesday afternoon, so this may help hinder Ozone development. We are rather confident that Ozone will not be a widespread issue on Wednesday and the rest of the week, so this forecast will be updated on Friday for the weekend ahead.

EXTENDED FORECAST:

Cooler summer temperatures remain in place for the weekend with a chance of rain as of right now. Overall air quality will remain Good.

Next Forecast update: Friday, August 11th, 2023. Forecast updated by Alec Knowacki.