7/22/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Thursday, July 22nd, 2021, through Monday, July 26th, 2021

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

PM-2.5:  24-hour average Fine Particulate concentrations are expected to increase from Good to Mid-Moderate throughout the forecast period.

FORECAST DISCUSSION

Recent forecasts have focused on the smoke transport into Michigan and how that is affecting Air Quality.  Fortunately, the wind patterns gave a momentary respite starting Tuesday evening and lasting through Thursday.  Unfortunately, the smoke and wildfire models are predicting the smoke will reenter the state during Friday.  While that will give the state hazy skies, the high-altitude smoke will stay mostly aloft.  Some will mix down, as seen earlier in the week, but our monitors should fare no worse than Moderate concentrations.

Currently, high pressure centered over SE Michigan is causing winds to shift back to a weak southerly direction.  As that high-pressure cell slips eastward, we will see our weather evolve into a more active weekend.  We are looking at a strong southwesterly flow, on Saturday, which will pump in high levels of moisture and the potential for convective activity.

A cold front is expected to drop down during Sunday and eliminate any threat from ozone.  However, since atmospheric smoke is expected to linger through the weekend, the state will be kept at Moderate levels.

EXTENDED FORECAST

Air Quality is expected to be Good increasing to Moderate going into the weekend.

Forecast updated by Jim Haywood: Thursday, July 22nd, 2021

Next forecast update: Monday, July 26nd, 2021

7/19/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Monday, July 19th, 2021, through Thursday, July 22nd, 2021

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

PM-2.5:  24-hour average Fine Particulate concentrations are expected to be mostly Low to Mid-Moderate throughout the forecast period.

FORECAST DISCUSSION

Air Quality for last week was really Good for ozone concentrations, which is very nice to see this time of year.  Fine particulates, however, ran well into the Moderate range, in many areas,  due mostly to atmosphere transport smoke from numerous large fires in the western United States and Canada.

This week will start off similarly.  For the first half of the week, ozone should be held at bay with northwesterly airflow. A pooling of ozone is expected over the bottom of Lake Michigan and perhaps some higher numbers could occur in the very southwest corner of the state if it bleeds inland.  The fire and smoke maps are showing coverage over almost the entire 48 lower contiguous states.  Only the very southeast and southwest corners of the country appear smoke-free.  This will help lower ozone numbers as effectively as a cloud cover.  But as some of that smoke mixes down to the surface, the monitors will reflect that in PM-2.5 creep. The fine particulate numbers will be similar to last week with concentrations ranging from Low Moderate to Mid-Moderate.

As high pressure slips eastward during the first half of the week, Expect a wind shift by late Thursday to the southwest.  With that shift comes the ozone forming pollutants from Illinois/Indiana and Southeast Michigan.  Because of that, the forecast will be updated on Thursday to reflect expected weekend conditions.

EXTENDED FORECAST

Air Quality is expected to be mostly Low Moderate going into the weekend.

Forecast updated by Jim Haywood: Monday, July 19th, 2021

Next forecast update: Monday, July 22nd, 2021

7/16/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Friday, July 16th, 2021 through Monday, July 19th, 2021

Ozone:  8-hour Ozone concentrations are expected to be mostly Good throughout the weekend. There will be some pooling of Ozone over Lake Michigan but with a northeast wind over the weekend, it should keep Ozone concentrations at bay.

PM-2.5: More of the same with PM-2.5 concentrations, northeast winds will keep potential wildfire smoke from entering the area and keeping PM-2.5 concentrations Good.

FORECAST DISCUSSION:

Upper-level temperatures will be in the low-teens for much of the weekend and into next week. Upper-level winds will be from the east which will help to keep wildfire smoke out of our area. Into the weekend a High-pressure system sets up over the Upper Peninsula providing clear and sunny skies for the region.

Surface temperatures look to be in the low-mid 80s for much of the weekend with the lower half of the state dealing with a stalled front which will provide relatively cooler temperatures to start the weekend, but the front will move out going into Saturday night. Surface winds appear to be easterly-northeasterly for the weekend, which, stated above, will help keep near-surface smoke from entering the area. In terms of dewpoint, there will be a rather sharp dewpoint gradient across the state Saturday ranging from the upper 50s to the north and upper 60s to the south. This is due to the stalled front over the Michigan/Ohio border. Going into Sunday as the front moves out, dewpoints drop across the state to the mid-50s.

EXTENDED FORECAST:

Going into Monday and next week, the High-pressure sticks around until a fast-moving cold front comes through from north to south Tuesday and into Wednesday. This cold front may produce some rain, but nothing too much. Overall, for the start of next week, concentrations should be mostly Good.

Forecast updated by Alec Kownacki/Stephanie Hengesbach: Friday, July 16th, 2021.

Next forecast update: Monday, July 19th, 2021

7/12/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Monday, July 12th, 2021 through Friday, July 16th, 2021

Ozone:  8-hour average Ozone concentrations are expected to be mostly Good throughout the week with a chance of Moderate concentrations in West Michgian along the Lake Michigan shoreline on Wednesday.

PM-2.5:  24-hour average fine Particulate concentrations will be mostly Good with low-Moderates possible from Canadian wildfire smoke plumes in the Upper Peninsula.

FORECAST DISCUSSION:

Upper-level temperatures will be in the low-teens for much of the week with some increasing into the mid-teens. Winds aloft shift from easterly at the beginning of the week to more west/southwesterly by mid-week. Clouds, precipitation chances, and easterly winds should keep air quality Good Monday into Tuesday.

The Low-pressure has a warm front associated with it that will result in warm air advection past mid-week as the boundary pulls north. This will also bring moisture into the region increasing surface dewpoint temperatures and humidity. Accompanied with the warmer temps, southwest winds are expected; however, clouds and precipitation move in the forecast Thursday into Friday as another Low-pressure area moves in. Clouds may clear long enough Wednesday to allow for a few Moderates ozone concentrations in western lakeshore areas; otherwise, levels will be generally Good. Fine particulate is expected to remain Good Wednesday. Clouds and precipitation should again keep ozone generally Good Thursday and Friday while fine particulate will likely be a mix of middle Good to low Moderate.

A weak cold front is expected Friday afternoon associated with the back end of the Low-pressure. This will make way for a High-pressure system to set up for the weekend. Canadian wildfires still present smoke plumes for the upper-Midwest region. The Upper Peninsula has a rather thick plume aloft on Monday which is expected to diminish in the coming days due to east-southeast winds for the first half of the week. These winds will also help to keep the plume out of the lower peninsula during the week, but northerly winds during the weekend may bring the plume back over the state.

EXTENDED FORECAST:

A high-pressure system sets up over the western Upper Peninsula region behind the cold front which should bring relatively clear skies and Good Ozone concentrations. We will update this forecast Friday to better detail possible pollution increases due to the wildfire smoke.

Forecast updated by Alec Kownacki/Stephanie Hengesbach: Monday, July 12th, 2021.

Next forecast update: Friday, July 16th, 2021

7/6/2021 Forecast Update

FORECAST SUMMARY: Tuesday, July 6th, 2021, through Monday, July 12th, 2021

OZONE: 8-Hour average Ozone concentrations are expected to be Moderate on Monday then transitioning to mostly Good to Moderate during Tuesday and for the remainder of the forecast period.

PM-2.5: 24-hour average Fine Particulate concentrations are expected to be Good to Moderate throughout the forecast period.

FORECAST DISCUSSION:

 The 4th of July holiday weekend is ideally hot and dry, but not too uncomfortable.  The past weekend, temperatures reached the 90-degree mark but did not feel too oppressive.  

As high pressure slipped eastward through the weekend, surface and upper-air winds were favorable through Saturday, and Air Quality Good.  As the center of the high-pressure ridge passed by on Sunday, surface winds turned to the southwest.  With that wind direction, especially this time of year, we tend to get concerned.  However, anyone who spent time outside probably noticed a thick haze over the sky which filtered out the harshest of the sun’s rays.  That haze was a thick layer of smoke over much of the Midwest courtesy of Canadian wildfires.  The wind shift on Sunday thinned out the layer of smoke and we did see a creep in the ozone numbers during Sunday and Monday, but it got no worse than Moderate.  

Fine particulates over a 4th of July holiday weekend always tend to run high due to fireworks.  While this weekend was no different, I do not think it was as bad as some years in the past.  That said, the Dearborn monitor did creep into the USG range on Sunday, but the rest of the state remained Moderate.  I did notice some of the northern monitors starting to creep into the Moderate range earlier in the weekend but that was likely the smoke layer mixing down to the surface.

Tuesday will still experience heat and plenty of Moderates for ozone and fine particulates, but the threat of elevated levels of ozone should be low and confined to the southwest corner of the state.  As a cold front drops through on Wednesday, that will eliminate any additional threats for the rest of the week.  We will be in a cleaner, cooler air mass and have Good Air Quality.  We will likely still see a smoke haze aloft and it will be interesting to see if any of that mixes down to the surface.  

Another warm-up is not expected until early next week, in advance of a low-pressure system.  As such, this forecast should be good through the weekend. 

EXTENDED FORECAST:

Air Quality should be Good to Low Moderate going into the next work week.

Forecast updated by Jim Haywood: Tuesday, July 6th, 2021.

Next forecast update: Monday, July 12th, 2021

7/3/2021 Forecast Update

FORECAST SUMMARY: Saturday, July 3rd, 2021, through Tuesday, July 6th, 2021

OZONE: 8-Hour average Ozone concentrations are expected to range from Good to Moderate.

PM-2.5: 24-hour average Fine Particulate concentrations will also be in the Good and Moderate range.

FORECAST DISCUSSION:

 The forecast is on track with generally sunny skies and warming temperatures this July 4th weekend. There is usually a bright blue sky in the current weather set-up, but it may look a bit hazy the next few days. That can be attributed to wildfire smoke sinking south from fires in Canada. The next weather system is a frontal boundary moving in later Monday. This system should bring some clouds later in the day and small chances for precipitation into Tuesday

For air quality, as mentioned wildfire smoke is traveling in from the north/northwest. While much of the plume should stay at upper levels, there is the possibility some may mix down increasing fine particulate concentrations into the Moderate range for a period of time. Because of this, they are forecasting Moderate fine particulate for the next two days. Another reason for a Moderate forecast increases in fireworks displays in celebration of the July 4th Holiday. These displays will cause short-term high spikes in fine particulate for a few hours afterward that could, in turn, allow for Moderate daily averages.

For ozone, there is currently a low background in place thanks to the stronger northwesterly winds the past few days. While surface and upper-level temperatures will continue to increase, the wind field remains from a non-conducive direction through most of Sunday. There is a small chance for a monitor or two right along the west Michigan lakeshore to reach low-end USG, but they do not foresee any widespread ozone concerns through July 4th.

A frontal boundary sinks closer to the region Monday. While winds turn more southwesterly, clouds look to move in early enough to hamper a significant ozone development. This is something that will be keeping an eye on, but for now, we are forecasting Moderate ozone Monday. They plan to take a look at weather maps again Sunday morning and will update this forecast if our thoughts change and we feel ozone concentrations higher than Moderate become a concern. The smoke plume forecast will be monitored and updated this forecast if warranted.

EXTENDED FORECAST:

The system dropping in from the north later Monday/early Tuesday should bring in cooler temperatures and cleaner air. Air quality by Tuesday should improve towards the Good range.

Forecast updated by Stephanie M. Hengesbach: Friday, July 2nd, 2021. Next forecast update: Tuesday, July 6, 2021

7/2/2021 Forecast Update

FORECAST SUMMARY: Friday, July 2nd, 2021, through Saturday, July 3rd, 2021

OZONE: 8-Hour average Ozone concentrations are expected to be mostly Good with only a few Moderates possible through Saturday.

PM-2.5: 24-hour average Fine Particulate concentrations will also be mostly Good.

FORECAST DISCUSSION:

High pressure to the southwest of the state will provide plentiful sunshine and northerly winds should keep air quality generally Good both Friday and Saturday. As it progresses into the holiday weekend, forecast models are showing a smoke plume dropping in from Canada. At this point, the smoke plume is expected to stay at upper levels and shouldn’t impact air quality significantly.

Another note as we move into the holiday weekend is the anticipated high fine particulate concentrations in locations with fireworks displays. Wind speeds should be high enough where levels will not stay high for a long period of time. Hourly levels during, and for a few hours after displays, maybe USG; however, daily averages should not be higher than low to middle Moderate.

Temperatures will increase Saturday and Sunday both at the surface and upper levels. By later Sunday winds turn more westerly as high pressure moves east. Plenty of sunshine will remain and the threat of increased ozone comes into play. This is something that will be monitored. This forecast will be updated Saturday to detail pollution levels for Sunday and Monday.

EXTENDED FORECAST:

Extended forecast models show the next system possibly bringing small chances for precipitation by late Monday or Tuesday. Until then, pollution levels may be increasing early next week for both ozone and fine particulate.

Forecast updated by Stephanie M. Hengesbach: Friday, July 2nd, 2021. Next forecast update: Saturday, July 3nd, 2021

6/28/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Monday, June 28th, 2021, through Friday, July 2nd, 2021

OZONE: 8-Hour average Ozone concentrations are expected to be mostly Good throughout the week with a chance of a few low Moderate concentrations due to southwesterly flow.

PM-2.5: 24-hour average Fine Particulate concentrations will be mostly Good with low-Moderates possible.

FORECAST DISCUSSION:

Monday, June 28th, presents relatively clear skies with dewpoints in the upper 60s to low 70s for the first half of the week. A lingering front provides a chance of some rain showers Monday afternoon and into the evening. The lingering front starts to lift off to the north as a Low-pressure system approaches the Great Lakes region and brings a cold front with it going into Wednesday, June 30th. With this frontal passage, winds shift from a southwesterly flow to a more westerly flow through mid-week. After the frontal passage Wednesday, a high-pressure system makes its way into the region from the north.

Going into Thursday, winds shift to a more northerly flow with temperatures in the upper-70s thanks to the passing cold front and this pattern stays relatively the same going into Friday, July 2nd. There is some question on an upper-level system bringing scattered precipitation Thursday and/or Friday, but by the end of the week and into the weekend a high-pressure system sets up directly over the Great Lakes region providing relatively clear skies. ozone levels will remain Good throughout the week and into the weekend with perhaps a few Moderates due to the southwesterly flow earlier on in the week. Particulate Matter appears to remain mostly Good with some areas reaching low Moderate levels throughout mid-week.

EXTENDED FORECAST:

Extended forecast models show a high-pressure system sitting over the Great Lakes region for much of the weekend. Going into Monday, July 5th, there appears to be a cold front approaching the region from the north which may impact the area early next week. We will post a forecast update on Friday to better detail air quality conditions for the July 4th weekend.

Forecast updated by Alec Kownacki: Monday, June 28th, 2021. Next forecast update: Friday, July 2nd, 2021

6/21/2021 Forecast Update

FORECAST SUMMARY:

FORECAST SUMMARY: Monday, June 21st, 2021 through Monday, June 28th, 2021

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

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

FORECAST DISCUSSION:

Following late Sunday thunderstorms, a cold front will pass through the state during Monday.  A cool down is expected behind the front with high pressure filling in for late Monday and Tuesday.  Air Quality is expected to be Good during the first half of the work week.

As the high pressure shifts eastward during mid-week, winds will migrate to a southerly direction.  Thursday promises to be the warmest day of the forecast period but not likely to persist long enough to promote any serious buildup of poor Air Quality.  That said, Moderate conditions during Thursday are to be expected.  Another cold front, late Friday, should push out any buildup that occurred during Thursday. 

Air Quality is expected to be Good Saturday and Sunday with a chance for a creep into the Moderate range on Monday as winds swing back to the south.

Overall, the Air Quality will be mostly Good, during the week, with Moderates during Thursday and possibly Monday.

EXTENDED FORECAST:

Air Quality should be Good to Low Moderate going into the next work week.

Forecast updated by Jim Haywood: Monday, June 21st, 2021. Next forecast update: Monday, June 28th, 2021

6/18/2021 Forecast Update

FORECAST SUMMARY:

FRIDAY, JUNE 18, THROUGH MONDAY, JUNE 21, 2021

OZONE: 8-hour Ozone concentrations are expected to be Good throughout the weekend with possible Moderate levels in place along the Lake Michigan shoreline and Metro Detroit. Into Monday, levels are expected to be Good due to another system making its way into the region.

PM-2.5: 24-hour average Fine Particulate concentrations will be Good to low Moderate over much of the region.

FORECAST DISCUSSION:

After a system made its way through the region Friday morning, subtle clearing is expected to occur for much of the afternoon with a moderate chance of additional storms to develop later Friday afternoon into the evening. Left over rain is expected into Saturday morning as another Mesoscale Convective System is predicted to make its way through central-southern Michigan. With this MCS, WSW winds are expected, which helps to explain the Moderate Ozone levels along the Lake Michigan shoreline.

Into the day on Saturday, a stalled front is expected over mid-Michigan, which will slightly lift off to the north later Saturday night, eventually making its way on a more SE track into Sunday and Monday. The stalled front will result in a Low-pressure system over the MI/IN border and will lift off as the front leaves the area. This front will be responsible for the expected rain on Monday. Overall, Ozone levels are expected to generally be Good with some Moderate levels of Ozone near west/southwest MI. In the southeast, low-Moderate PM2.5 concentrations could occur as well.

EXTENDED FORECAST:

With the frontal passage next Monday, we expect Good Air Quality for the start of the week as the rain showers exit the area. This will give way to a High-pressure system to our south which will present us with relatively clear skies.

FORECAST UPDATED BY ALEC KOWNACKI/STEPHANIE HENGESBACH: FRIDAY, JUNE 18, 2021

NEXT FORECAST UPDATE: MONDAY, JUNE 21, 2021

6/14/2021 Forecast Update

FORECAST SUMMARY:

MONDAY, JUNE 14, THROUGH FRIDAY, JUNE 18, 2021

OZONE: 8-Hour average Ozone concentrations are expected to be mostly Good through mid-week with Moderates possible Thursday. Good levels return Friday.

PM-2.5: 24-hour average fine particulate concentrations will be mostly Good with low-Moderates possible past midweek.

FORECAST DISCUSSION:

A cooler, cleaner airmass will be in place through mid-week with generally Good levels of ozone and fine particulate. Weak upper-level systems bring scattered to isolated diurnal showers in the forecast Monday and again Tuesday. Otherwise, surface high pressure moving in keeps primarily dry, pleasant conditions in place. The next weather system is a cold front forecast to pass later Thursday into Friday.

 With a northerly wind in place mostly Good ozone and particulate is expected through Wednesday. Lighter winds in the morning may allow hourly fine particulate to reach low Moderate for a few hours in the southeast; however, daily averages should remain mostly Good. By Thursday, a warmer southwest flow returns ahead of the next system. Thursday has the best chance for Moderate ozone and/or fine particulate. At this time, I don’t foresee pollution reaching higher than Moderate, but if our thoughts on that change, we will update this forecast Wednesday. Clouds and precipitation by Friday should keep ozone Good while fine particulate may reach low Moderate in a few locations.

EXTENDED FORECAST:

Extended forecast models show high pressure and warming temperature by the end of the weekend, but showers and storms may return Monday. Considering the time of year, we will update this forecast Friday to better detail expected air quality conditions for the weekend into early next week.

FORECAST UPDATED BY STEPHANIE HENGESBACH: MONDAY, JUNE 14, 2021
NEXT FORECAST UPDATE: FRIDAY, JUNE 18, 2021

6/7/2021 Forecast Update

FORECAST SUMMARY:

MONDAY, JUNE 7, THROUGH MONDAY, JUNE 14, 2021

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

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

FORECAST DISCUSSION:

The past weekend was a bit busy in terms of forecasting elevated ozone.  Mother Nature did share the pain throughout the state with West Michigan having the most impacted monitors on Friday, Southeast Michigan hit hardest on Saturday, and Seney in the U.P. was the lone high monitor on Sunday. 

This week will still have temperatures in the mid-80’s but we should not see much in the way of elevated ozone.  We can thank mostly overcast skies and frequent chances of precipitation to keep ozone levels in check for most of the work week.  Fine particulates, however, could still reach the Moderate levels as sunlight is not necessary for the growth of PM-2.5 particulates.

Right now, the long-range forecast is showing a warm front boundary over Michigan on Saturday followed by a cold front passage on Sunday.  This would clean out the atmosphere and start the next week in the Good category with cooler temperatures and less humidity.  As such, the chances for any pollutants reaching the USG levels during this forecast period are low and the next forecast is scheduled for next Monday.  Should conditions change we will update this forecast, as necessary.

EXTENDED FORECAST:

Air Quality should be mostly Good going into the next work week.

FORECAST UPDATED BY JIM HAYWOOD: MONDAY, JUNE 7, 2021
NEXT FORECAST UPDATE: MONDAY, JUNE 14, 2021

6/06/2021 Forecast Update

FORECAST SUMMARY:

Sunday, June 6th, 2021 through Monday, June 7th, 2021 

OZONE: 8-Hour average Ozone concentrations are expected to range from Moderate to USG Sunday and Good to Moderate Monday.

PM-2.5: 24-hour average Fine Particulate concentrations will be in the Good to low Moderate range.

FORECAST DISCUSSION:

Sunny skies and warm temperatures can be expected today. Ozone levels on Saturday ranged from Moderate to high USG with most USG readings in the west and southeast Michigan. The threat for increased ozone continues today and we have an Air Quality Action Day in place to cover this threat. An upper-level system moves in from the south, late Sunday into Monday. This system brings clouds, moisture, and chances for scattered, heavy rain. While warm temperatures continue, ozone concentrations should finally decrease; therefore, we will not continue the Air Quality Action Day into Monday. 

Strong winds the past few days have helped keep fine particulate readings in check. Levels Sunday and Monday are not expected to reach higher than low Moderate.

EXTENDED FORECAST:

Extended forecast models show the upper system lingering over the state for most of the week. This would keep clouds and precipitation chances in the forecast, and with this, air pollution levels should not increase significantly.

Forecast updated by Stephanie Hengesbach: Sunday, June 6th, 2021

Next forecast update: Monday, June 7th, 2021

6/05/2021 Forecast Update

FORECAST SUMMARY:

Saturday, June 5th, 2021 through Sunday, June 6th, 2021 

OZONE: 8-Hour average Ozone concentrations are expected to range from Moderate to USG. 

PM-2.5: 24-hour average Fine Particulate concentrations will be in the upper Good to middle Moderate range.

FORECAST DISCUSSION:

The forecast is on track as expected with sunny skies, warm temperatures, and strong west to southwest winds. The only exception is a frontal boundary bringing some clouds and precipitation to the upper peninsula and extreme northern lower peninsula.

Ozone ranged from Moderate to USG Friday across the state and readings in that range are still expected Saturday. This coincides with the current Air Quality Action Day we have in place. Since the forecast does not change as we move into Sunday, we are keeping the Air Quality Action Day in place through Sunday for both west and southeast Michigan. Forecast models show chances for precipitation as early as Monday. Forecast maps will be evaluated Sunday morning and this forecast will be updated to determine if the Action Day needs to be extended.

Fine particulate readings are in the upper Good to low Moderate range, and levels in that range will continue through the weekend.

EXTENDED FORECAST:

Extended forecast models are hinting at chances for storms Monday/Tuesday of next week. Until weather conditions change, we will be doing daily updates of the air quality forecast.

Forecast updated by Stephanie Hengesbach: Saturday, June 5th, 2021

Next forecast update: Sunday, June 6th, 2021

6/04/2021 Forecast Update

FORECAST SUMMARY:

Friday, June 4th, 2021 through Saturday, June 5th, 2021

OZONE: 8-Hour average Ozone concentrations are expected to range from Moderate to USG.

PM-2.5: 24-hour average Fine Particulate concentrations will be in the upper Good to middle Moderate range.

FORECAST DISCUSSION:

The forecast is on track for a continued warm-up as we progress into the weekend. Aside from small chances for rain in the upper peninsula Saturday through Sunday, the forecast is calling for mostly sunny skies, warm surface and upper-level temperatures, and stronger winds from the west/southwest. Ozone concentrations reached low-end USG Thursday along portions of the West Michigan lakeshore. A few locations may reach low-end USG Friday; however, by Saturday more widespread USG readings are expected. Because of this, we are issuing an Air Quality Action Day for much of west Michigan, from north to south along the western lakeshore and on county inland.

Ozone has been slower to increase in the southeastern portion of the state, likely because of more cloud cover Thursday. Ozone in the central and eastern areas should remain Moderate Friday, but conditions by Saturday become more conducive for ozone development. We are also issuing an Air Quality Action Day for southeastern areas Saturday to cover the threat of increased ozone.

Fine particulate readings have been consistently in the upper Good to low Moderate range, and levels in the range will continue through the weekend. 

EXTENDED FORECAST:

Extended forecast models are hinting at chances for storms around Monday/Tuesday of next week. Until cleanout of the current airmass, we will be doing daily updates for the air quality forecast.

Forecast updated by Stephanie Hengesbach: Friday, June 4th, 2021

Next forecast update: Saturday, June 5th, 2021

6/03/2021 Forecast Update

FORECAST SUMMARY:

Thursday, June 3rd, 2021 through Friday, June 4th, 2021

OZONE: 8-Hour average Ozone concentrations are expected to be mostly Good with small chances for USG along the West Michigan lakeshore.

PM-2.5: 24-hour average Fine Particulate concentrations will be in the upper Good to middle Moderate range.

FORECAST DISCUSSION:

A weak system over southwest Ontario will continue moving east today as a boundary sinks in from the north. Generally, sunny and warm conditions are expected Thursday with a bit more clouds near the systems in the southeast and northern areas. Ozone concentrations have reached just over the USG threshold at a few locations right along the lakeshore of West Michigan Wednesday, and this may happen again Thursday. The greatest chance for low-end USG will be south of Muskegon. Overall, however, Moderate ozone is expected.

The system dropping in from the north brings clouds and small chances for precipitation overnight Thursday into early Friday morning. Clouds will decrease as the day progresses Friday. Warmer conditions continue and if clouds clear out early enough a monitor or two may reach low-end USG, however, we don’t feel the threat at this time warrants an Action Day Advisory for Friday. Conditions for the weekend look to deteriorate regarding air quality. Warm surface and upper-level temperatures will be in place, skies will be sunny, and southwest/west winds prevail. Because of this, we are having another regional forecast call Friday morning to decide if Action Day Advisories will be issued for Saturday.

Fine particulate is currently ranging in the upper Good to middle Moderate range and without a clean air mass moving in, levels in the range will continue.

EXTENDED FORECAST:

Extended forecast models continue showing increased temperatures and dry conditions into early next week. This will continue to keep the threat of increased ozone levels.

Forecast updated by Stephanie Hengesbach: Tuesday, June 3rd, 2021
Next forecast update: Friday, June 4th, 2021

6/01/2021 Forecast Update

FORECAST SUMMARY:

Tuesday, June 1st, 2021 through Thursday, June 3rd, 2021

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

PM-2.5:  24-hour average Fine Particulate concentrations will be in the upper Good and middle Moderate range.

FORECAST DISCUSSION:

High-pressure Tuesday will keep quiet conditions in place. Light winds, temperatures in the 70s, and plenty of sunshine allow for some Moderate ozone and/or fine particulate. A trough moving in Wednesday brings clouds and precipitation changes to parts of the state. This system keeps ozone from increasing, and readings should range from Good to low Moderate both Wednesday and Thursday. Fine particulate is expected to continue in the Good to low Moderate range.

After Thursday, surface high pressure will be the dominating factor and upper-level ridging will build in for the weekend. Warm air advection with increasing temperatures both at the surface and upper levels can be expected. The question mark is a convective potential late in the week. If conditions remain dry and sunny, ozone may be increasing as we move towards the weekend. Because the threat for higher ozone begins Friday, we will be updating this forecast Thursday to evaluate the need for any Air Quality Action Days.

EXTENDED FORECAST:

Extended forecast models show increased temperatures lasting through the weekend. If dry conditions also remain the trend, we will be updating the forecast daily as we move through the period.

Forecast updated by Stephanie Hengesbach: Tuesday, June 1st, 2021
Next forecast update: Thursday, June 3rd, 2021

5/28/2021 Forecast Update

FORECAST SUMMARY:

Friday, May 28th, 2021 through Tuesday, June 1st, 2021

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

PM-2.5:  24-hour average Fine Particulate concentrations are also expected to be mostly Good with a small chance of Moderate Monday and Tuesday in the urban and transport areas.

FORECAST DISCUSSION:

A low-pressure system along the Illinois and Indiana border is providing stiff, cool, wet northeast winds Friday morning.  As that system slides eastward, it will be replaced by advancing high pressure, which will keep our winds from a clean northeast direction Saturday and Sunday.  Air Quality will remain Good.

As the high pressure migrates eastward, we will begin to come under southwesterly winds and a gradual warm up during Monday.  Since the background Air Quality will still be Good and temperatures still relatively cool, the threat of any significant ozone is small.  We could, however, see some small build-up of fine particulates along the lower Lake Michigan shore and Detroit areas.  At worst, these should be Low Moderate.

All in all, the holiday weekend should be cool and pleasant once the high pressure moves in on Saturday and the Air Quality should be mostly Good through the forecast period.

EXTENDED FORECAST:

Air Quality should be mostly Good going into the next work week.

Forecast updated by Jim Haywood: Friday, May 28th, 2021
Next forecast update: Tuesday, June 1st, 2021

5/24/2021 Forecast Update

FORECAST SUMMARY:

Monday, May 24th, 2021 through Friday, May 28th, 2021

Ozone:  8-hour average Ozone concentrations are expected to be Good to Moderate early in the week, then mostly Good.

PM-2.5:  24-hour average Fine Particulate concentrations are also expected to be mostly Good to Moderate early in the week, then mostly Good.

FORECAST DISCUSSION

A cold front, which settled through the state Sunday night, is just south of the Michigan/Indiana border at the time of this Monday morning forecast.  It is expected to reverse course and head back north as a warm front through the day Monday and into Tuesday.  The area around this front will produce clouds and scattered showers which will reduce any threat of ozone.   We can, however, still expect Moderate levels of fine particulates in the southern tier counties. 

Tuesday will have the best chance of higher ozone concentrations along the Lake Michigan shore counties.  Southwest winds will transport pollutants across the lake with warm temperatures and ample humidity.  However, the potential of sustained, ample sunlight will be scattered and concentrations of higher ozone will follow suite.  With the high probability of broken to overcast cloud cover, I do not see the potential for any widespread areas of USG level ozone. 

A stronger cold front should travel across the state early Wednesday and clean out the current air mass.  The remainder of the forecast period should see wind patterns ranging from northerly to easterly as another low-pressure system slowly tracks to the south of us.

As such, I expect the period of Wednesday through the weekend to yield mostly Good Air Quality.  At worst, we could see some Moderate conditions west of Detroit as those easterly winds kick in.

As of now, it looks safe to extend the forecast through the holiday weekend.  But considering this is the time of year where ozone activity amps up, I will update this forecast on Friday to get us through the long weekend.

EXTENDED FORECAST:

Air Quality should be mostly Good going into the next work week.
Forecast updated by Jim Haywood: Monday, May 24th, 2021 Next forecast update: Friday, May 28th, 2021

5/21/2021 Forecast Update

FORECAST SUMMARY:

FRIDAY, MAY 21st, THROUGH MONDAY, MAY 24, 2021

OZONE: 8-Hour average Ozone concentrations are expected to range from Good to Moderate with USG possible in the west and southeast, especially Friday. The rest of the period should range between Good and Moderate.

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

AIR QUALITY ACTION DAY ADVISORY FOR FRIDAY, MAY 21ST, FOR THE FOLLOWING COUNTIES:

ALLEGAN, BERRIEN, CASS, KENT, MUSKEGON, OTTAWA, and VAN BUREN

FORECAST DISCUSSION:

Warm and humid weather lasts through the weekend; however, a frontal boundary sinks in from the north and settles into southern portions of the state Saturday. This boundary should provide more in the way of cloud cover and chances for scattered precipitation. The boundary lingers over the region early next week keeping partly to mostly cloudy skies and scattered precipitation.

As for air quality, less cloud cover is expected Friday and the threat for increased ozone in the west and southeast remains. Warm/muggy conditions continue Saturday through Monday, but more clouds, scattered precipitation, and wind shifts to the west/northwest Saturday/Sunday should hamper significant increases in ozone. Isolated areas that end up with more sunshine could possibly reach low-end USG, but the threat is not high enough at this time to warrant action days. We are keeping a Moderate ozone forecast Saturday through Monday and we will evaluate forecast maps this weekend. If conditions worsen where we feel increased ozone is likely, this forecast will be updated.

Fine particulate has been a mix of upper Good to middle Moderate and without a change in airmass anticipated, mostly Moderate readings continue.

EXTENDED FORECAST:

Extended forecast models finally hint at a change in airmass around mid-week with a stronger front passing through. Until then, expect warmer conditions, scattered precipitation, and mostly Moderate ozone and fine particulate.

FORECAST UPDATED BY STEPHANIE HENGESBACH: FRIDAY, MAY 21, 2021
NEXT FORECAST UPDATE: MONDAY, MAY 24, 2021