7/13/2020 Forecast Update

FORECAST SUMMARY:

Monday, July 13th, 2020 through Friday, July 17th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Good on Monday increasing to a mixture of Good and Moderate on the remaining days through Friday. 

PM-2.5:  24-hour average Fine Particulate concentrations will range from Good to Moderate.

FORECAST DISCUSSION

The last forecast discussion, posted last Wednesday, held true for the most part.  During Thursday, we saw several monitors in Southeast Michigan go over the USG threshold.  Monitors in West Michigan managed to stay just under 70 ppb.  The cold front that went through on Friday did an excellent job of cleaning out the atmosphere.  In fact, levels on Sunday resembled more what we see in January rather than July. 

Monday concentrations are also expected to stay in the typical winter range before high pressure passes over, during Tuesday, and we get into a southwest wind pattern.  Fortunately, since the air is extremely clean, we will stay mostly Good but we can expect a bit of an uptick in Southeast Michigan and along the Lake Michigan lake shore.

A front is expected to pass during Wednesday and the associated clouds and showers will help keep numbers down.  The clean-out from that front should keep us mostly Good with some scattered Moderates through Friday.

Saturday could be interesting as a persistent southwest wind, sunny skies, and increasing temperatures could present a problem.  As such, Friday will be our next forecast unless conditions change enough to warrant an update before then. 

EXTENDED FORECAST:

Air Quality should be mostly Good to Moderate going into the weekend.  We could see elevated ozone during the weekend.

Forecast updated by Jim Haywood: Monday, July 13th, 2020
Next forecast update: Friday, July 17th, 2020

7/8/2020 Forecast Update

FORECAST SUMMARY:

Wednesday, July 8th, 2020 through Monday, July 13th, 2020

OZONE: 8-Hour average Ozone concentrations will be Moderate with a good chance of USG along the southern tier counties of Lake Michigan and Southeast Michigan during Thursday, then transitioning from Moderate to Good during Friday.  Conditions should be Good during the weekend.

PM-2.5:  24-hour average Fine Particulate concentrations will range from Good to Moderate.

AN ACTION DAY ADVISORY IS ISSUED FOR WEDNESDAY and THURSDAY FOR THE FOLLOWING MICHIGAN COUNTIES...

WEST MICHIGAN

ALLEGAN...  BERRIEN…  CASS…  KENT...  MUSKEGON...  OTTAWA… AND VAN BUREN COUNTIES; AND

SOUTHEAST MICHIGAN

LIVINGSTON…  MACOMB…  MONROE…  OAKLAND… ST. CLAIR…  WASHTENAW…  AND WAYNE COUNTIES

FORECAST DISCUSSION

Hot, sunny weather is expected to continue through Thursday before relief arrives in the form of a cold front during Friday.  Tuesday experienced ozone concentrations in excess of 70 ppb in both Southeast Michigan and West Michigan, although Southeast Michigan has been getting hit harder during this episode.  While light winds have slowed the Chicago plume from impacting West Michigan too severely, it has hurt Southeast Michigan where wind stagnation has caused an accumulation of bad air.

As a result, we will be keeping the Action Day advisories in place through Thursday in both areas.  Pop-up shower activity is increasingly possible during Wednesday and Thursday that would provide localized cleanout, but not enough to completely clean out the problem areas.

The expected cold front will arrive along the West Michigan shoreline around 8AM Friday morning and slowly progress across the state.  There is some slight concern that Southeast Michigan will not see the cleanout benefit of the front before Friday concentrations elevate but clouds and shower actively ahead of the front should keep those concentrations in check.

Clean, cooler air will follow the front and eliminate the need for further advisories during the weekend.  I do expect another low-pressure system to pass over the state during Sunday and follow with more clean air on Monday.  As such, I think this forecast should be good through the weekend.  Should conditions change significantly, we will update this forecast, as necessary.

EXTENDED FORECAST:

Air Quality should be mostly Good at the start of the next work week.

Forecast updated by Jim Haywood: Wednesday, July 8th, 2020
Next forecast update: Monday, July 13th, 2020

7/7/2020 Forecast Update

FORECAST SUMMARY:

Tuesday, July 7th, 2020 through Wednesday, July 8th, 2020

OZONE: 8-hour average Ozone concentrations will be Moderate with a good chance of USG along the southern tier counties of Lake Michigan and Southeast Michigan.

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to Moderate.

AN ACTION DAY ADVISORY IS ISSUED FOR TUESDAY JULY 7th AND WEDNESDAY JULY 8th FOR THE FOLLOWING COUNTIES:

IN WEST MICHIGAN:

ALLEGAN... berrien… CASS… KENT... MUSKEGON... ottawa… AND van buren COUNTIES

IN Southeast MICHIGAN:

LIVINGSTON… MACOMB… MONROE… OAKLAND… ST. CLAIR… WASHTENAW… AND WAYNE COUNTIES

FORECAST DISCUSSION:

Hot, sunny conditions continue as we move through mid-week. Forecast models finally show some relief Friday as a cold front passes through.

On Monday we saw our first day with USG ozone across the southeast; levels remained mostly Moderate across the rest of the state. Wind patterns are now starting to become more persistently west and southwest at all levels of the atmosphere. This means that we can expect ozone numbers to steadily climb past mid-week. Most of the ozone models have been performing well and almost all are showing a jump in numbers Tuesday and Wednesday. As the atmosphere gets more humid, chances increase for pop-up showers/storms, but that will be scattered enough not to help in the big picture. Therefore, we are continuing our Air Quality Advisories in the west and southeast.

Fine particulate has also been climbing the past few days. Most locations have been Moderate and more widespread Moderates are likely until the front passes Friday.

EXTENDED FORECAST:

Air Quality will stay mostly Moderate with USG in the most susceptible areas the next few days; improvement will likely come towards the end of the week.

Forecast Updated by Stephanie M. Hengesbach on July 7th, 2020.
Next forecast update: Wednesday, July 8th, 2020

7/6/2020 Forecast Update

FORECAST SUMMARY:

Monday, July 6th, 2020 through Tuesday, July 7th, 2020

OZONE: 8-Hour average Ozone concentrations will be Moderate with a good chance of USG along the southern tier counties of Lake Michigan and Southeast Michigan.

PM-2.5:  24-hour average Fine Particulate concentrations will range from Good to Moderate.

AN ACTION DAY ADVISORY IS ISSUED FOR MONDAY and TUESDAY FOR THE FOLLOWING MICHIGAN COUNTIES...

WEST MICHIGAN

ALLEGAN...  BERRIEN…  CASS…  KENT...  MUSKEGON...  OTTAWA… AND VAN BUREN COUNTIES; AND

SOUTHEAST MICHIGAN

LIVINGSTON…  MACOMB…  MONROE…  OAKLAND… ST. CLAIR…  WASHTENAW…  AND WAYNE COUNTIES

FORECAST DISCUSSION

Hot, sunny weather is expected to continue until the end of the work week.  A front is expected to pass Friday morning to finally provide relief.

For the most part, Michigan has been spared elevated ozone during this hot weather spell.  Because of the wind patterns, most of the pollutants have impacted the other side of Lake Michigan.  Southeast Michigan has been spared because winds, light as they were, came from non-polluted areas and helped dilute down local stagnation.

We began issuing Air Quality Advisories on Saturday because winds have slowly begun migrating around to the southwest.  So far, those winds have been light enough that the bad air has not made it to our shores.  We did have some exceptional high particulate numbers in the Southeast, over the weekend, but that can be traced back to firework displays.

Wind patterns are now starting to stabilize and be persistently from the west and southwest at all levels of the atmosphere.  This means that we can expect ozone numbers to steadily climb during the week.  Most of the ozone models have been performing well and all are showing a jump in numbers, this week.  As the atmosphere gets more humid, chances increase for pop-up showers, but that will be scattered enough not to help in the big picture.

As such, we are continuing our Air Quality Advisories, in the most susceptible areas, along with daily forecast updates.

EXTENDED FORECAST:

Air Quality will stay mostly Moderate with USG likely in the most susceptible areas.

Forecast updated by Jim Haywood: Monday, July 6th, 2020
Next forecast update: Tuesday, July 7th, 2020

7/5/2020 Forecast Update

FORECAST SUMMARY:

Sunday, July 5th, 2020 through Monday, July 6th, 2020

OZONE: 8-hour average Ozone concentrations will be Moderate with a good chance of USG along the southern tier counties of Lake Michigan.

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to upper Moderate.

AN ACTION DAY ADVISORY IS ISSUED FOR SUNDAY JULY 5th AND MONDAY JULY 6th FOR THE FOLLOWING WEST MICHIGAN COUNTIES:

ALLEGAN...  BERRIEN…  CASS…  KENT...  MUSKEGON...  OTTAWA… AND VAN BUREN

Weather conditions remain unchanged as we continue with the weekend regarding hot temperatures and increased humidity levels. Forecast models are showing the persistent high-pressure area moving overhead, then the east on Sunday. Although still not that strong, winds will change to a more southwesterly direction.  Seeing that many monitors in Indiana, Illinois, and southern Wisconsin have reached USG for ozone late last week, we feel action day advisories are warranted with the wind flow now coming from a southerly direction. Favorable winds will also continue in the southeast and without an air mass change, advisories seem wise there, as well.

The long-range computer forecast keeps us in the same hot, humid air mass until the end of next week so we expect more advisories may be forthcoming.  As such, these forecasts will continue to be updated daily.

Fine particulate has also been on the increase, likely due to localized fireworks. Hourly concentrations Sunday morning were up into the USG range. With light winds, fine particulate will be slow to improve, therefore, 24-hour concentrations Sunday will be upper Moderate in many locations, with Moderates lingering into Monday.

EXTENDED FORECAST:

Air Quality will stay mostly Moderate with USG in the most susceptible areas.

Forecast updated by: Stephanie M. Hengesbach; July 5, 2020
Next forecast update: Monday, July 6th, 2020

7/4/2020 Forecast Update

FORECAST SUMMARY:

Saturday, July 4th, 2020 through Sunday, July 5th, 2020

OZONE: 8-Hour average Ozone concentrations will be Moderate with a good chance of USG along the southern tier counties of Lake Michigan

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderate.

AN ACTION DAY ADVISORY IS ISSUED FOR SUNDAY FOR THE FOLLOWING WEST MICHIGAN COUNTIES...

ALLEGAN...  BERRIEN…  CASS…  KENT...  MUSKEGON...  OTTAWA… AND VAN BUREN

FORECAST DISCUSSION

Despite the hot weather, Air Quality has stayed remarkably good through the week.  We have recorded only one USG and that was the East 7-Mile monitor on Thursday.  Much of that good fortune can be traced back to favorable winds which switched from southeast to northwest during the course of the week. 

Now the models are showing that the high pressure ridge axis will pass over during Sunday and light winds will switch to the southwest.  Seeing that many monitors in Indiana, Illinois, and southern Wisconsin hit USG, yesterday, we think it prudent to issue an advisory since winds will now come from that direction. 

Long range computer forecast keeps us in the same hot, humid air mass until the end of next week so I expect more advisories may be forthcoming.  As such, these forecasts will continue to be updated daily.

EXTENDED FORECAST:

Air Quality will stay mostly Moderate with USG in the most susceptible areas.

Forecast updated by Jim Haywood: Saturday, July 4th, 2020

Next forecast update: Sunday, July 5th, 2020

7/3/2020 Forecast Update

FORECAST SUMMARY:

Friday, July 3rd, 2020 through Saturday, July 4th, 2020

OZONE: 8-hour average Ozone concentrations will be mostly Moderate with a chance for isolated USG; Air Quality may decrease as we move into early next week.

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to middle Moderate through the weekend.

FORECAST DISCUSSION:

Conditions, for the most part, remain unchanged Friday and Saturday. The only exception is a weak shortwave dropping in Friday may trigger isolated storms in the afternoon/evening. Otherwise, hot, humid, and sunny conditions continue through the July 4th holiday.

As for air quality, there was one monitor in the southeastern portion of the state that went just over the USG threshold Thursday. Besides that, readings were mostly upper Good to upper Moderate. Friday and Saturday, surface and upper levels winds remain northwesterly to northeasterly. Again, there may be an isolated monitor or two that hit USG either along the west Michigan lakeshore or in the southeast, but we are expecting most sites to remain Moderate.

As we continue into the weekend, winds look to turn more southerly by Sunday. With yet another day under pretty much the same air mass, the chance for increased ozone remains. We will evaluate weather maps and update the forecast Saturday to determine if any action days are warranted for Sunday.

Light winds and no air mass change has allowed for an uptick in fine particulate. With conditions not changing, and possibly localized fireworks displays over the next few days, we are expecting fine particulate to range from upper Good to mostly Moderate through the weekend.

EXTENDED FORECAST:

With the continued uncertainty in the air quality forecast, we will update the forecast daily. For now, we expected ozone will stay mostly Moderate and perhaps an isolated USG moving into the weekend.

Forecast updated by: Stephanie M. Hengesbach
Next forecast update: Saturday, July 4th, 2020

7/2/2020 Forecast Update

FORECAST SUMMARY:

Thursday, July 2nd, 2020 through Friday, July 3rd, 2020

OZONE: 8-hour average Ozone concentrations will be mostly Moderate with a chance for isolated USG Thursday and Friday. Air Quality may decrease as we move into the holiday weekend.

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to middle Moderate through the weekend.

FORECAST DISCUSSION:

As we move towards the July 4th holiday, the weather remains hot, humid, and sunny. The air quality forecast remains consistent that even though we are still in the same air mass, there has been little variation in the ozone concentrations over the past few days. In fact, ozone levels in many locations were lower Wednesday than Tuesday, and we have yet to see a USG concentration this week.

The computer ozone models, for the most part, are staying steady with ozone concentrations. One model shows a spike Thursday and Friday right along the west Michigan lakeshore while all the other models are showing status quo or a slight decrease on Friday. After again evaluating the expected wind patterns, models still show winds from to a northerly component Thursday and Friday at all levels of the atmosphere. This does not mean we will get any relief from the temperatures or humidity, but it does mean the winds will not be pushing pollutants towards us from the high pollution urban areas.

As a result, the forecast remains Moderate for ozone Thursday and Friday. Considering the time of year and the current weather conditions, however, it is never totally out of the question that an isolated location could cross into the USG zone. If that happens, the AirNow forecast map will be updated to reflect that change.

Light winds and no air mass change has allowed for an uptick in fine particulate. With conditions not changing, and possibly localized fireworks displays over the next few days, fine particulate is expected to range from upper Good to mostly Moderate through the weekend.

EXTENDED FORECAST:

With so much uncertainty in the air quality forecast, we will continue with daily updates. For now, ozone is expected to remain mostly Moderate with perhaps an isolated USG moving into the weekend.

Forecast updated by: Stephanie M. Hengesbach
Next forecast update: Friday, July 3rd, 2020

7/1/2020 Forecast Update

FORECAST SUMMARY:

Wednesday, July 1st, 2020 through Thursday, July 2nd, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate with a chance of isolated USG during Wednesday and Thursday.  Air Quality may decrease over the course of the week.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderate through the week.

FORECAST DISCUSSION

The weather remains hot, humid, and sunny for the week and is expected to continue through the holiday weekend.  Interesting enough, even though we remain in the same air mass under intense sun, there has been little variation in the ozone concentrations over the past two days.  Along the West Michigan lake shore, inland monitors decreased during Tuesday while coastal monitors remained the same or slightly increased.  In all cases, we have yet to see a USG concentration, this week.

The computer ozone models, for the most part, are staying with consistent ozone concentrations for midweek.  Only one model is showing a spike for Thursday while all the other models are showing status quo or a slight decrease.  All weather models are showing a shift of winds to a northerly component, at all levels of the atmosphere, during Thursday.  This does not mean we will get any relief from the temperatures or humidity because we stay in the same air mass.  But it does mean the winds will not be pushing pollutants towards us from the high pollution urban areas.

As a result, the forecast is in the Moderate range.  Considering the time of year and the current weather conditions, however, it is never totally out of the question that some isolated spots could cross into the USG zone.  If that happens, we will update the AirNow forecast map to reflect that change.

EXTENDED FORECAST:

Air Quality will stay mostly Moderate and perhaps an isolated USG during the latter half of the week.

Forecast updated by Jim Haywood: Wednesday, July 1st, 2020
Next forecast update: Thursday, July 2nd, 2020

6/30/2020 Forecast Update

FORECAST SUMMARY:

Tuesday, June 30th, 2020 through Wednesday, July 1st, 2020

OZONE: 8-hour average Ozone concentrations will be mostly Moderate Tuesday and Wednesday. Air Quality will likely decrease past mid-week.

PM-2.5: 24-hour average Fine Particulate concentrations will range from Good to Low Moderate through the week.

FORECAST DISCUSSION:

A warm, dry forecast remains as we continue into the week. Ozone levels Monday ranged from Good to middle Moderate across the state. Those readings were an increase from Sunday, but forecast models are showing no higher than Moderate ozone through Wednesday. Considering that, and the fact levels Tuesday morning are the same or a bit lower than the same time Monday, we are keeping with a Moderate ozone forecast through Wednesday. There is still a small chance for a monitor or two to reach USG, but we feel this would be an isolated event. As was stated yesterday, with east/southeast winds, the area with the highest potential will be west/northwest of the Detroit area and/or along the immediate West Michigan lakeshore.

Without a change in airmass this week we anticipate ozone to continue a slow climb over the next few days. Also, given the fact that we are in the period of the summer when ozone production potential is at its highest, we will be watching closely the entire week.

With the expected forecast, fine particulate will range from upper Good to low Moderate.

EXTENDED FORECAST:

Air Quality will likely elevate to Moderate and perhaps USG during the latter half of the week.

Forecast updated by: Stephanie M. Hengesbach, 6/30/2020.
Next forecast update: Wednesday, July 1st, 2020

6/29/2020 Forecast Update

FORECAST SUMMARY:

Monday, June 29th, 2020 through Tuesday, June 30th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Good to Moderate during Monday and Tuesday.  Air Quality will likely decrease over the course of the week.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderate through the week.

FORECAST DISCUSSION

The week is shaping up to be a warm one as we approach the holiday weekend.  Fortunately, Air Quality was Good, over the weekend, so we are starting off with a clean base.  With that said, the week promises to be sunny, hot, and humid.  The only real chance of clouds and shower activity will be in the extreme southwest corner of the state which could be affected by a stationary front over Illinois and Indiana.  But that is only for late Monday and Tuesday. 

In many ways, the weather models are showing a very similar setup to what we saw, two weeks ago, when we had elevated ozone for the much of the week.  The ozone models, however, are not showing much in the way of ozone development early this week.  The surface winds for the week look to be light and biased from the southeast, just as it was two weeks ago.  The upper air winds look to have a northerly component, for much of the week, which will be clean and can mix down.  Another factor is that the atmosphere had high levels of smoke over the Midwest, two weeks ago, and that certainly could have contributed to the higher ozone levels.  Today, the maps indicate no smoke over the Midwest.

With all these factors, I do not see Tuesday as having a high threat for widespread elevated ozone.  With the southeast winds, the area with the highest potential will be northwest of the Detroit area.  Even so, the models are not indicating anything worse than High Moderate.

Given the fact that we are in the period of the summer when ozone production potential is at its highest, we will be watching closely the entire week.  As such, I anticipate a daily update to this forecast every day.

EXTENDED FORECAST:

Air Quality will likely elevate to Moderate and perhaps USG during the latter half of the week.

Forecast updated by Jim Haywood: Monday, June 29th, 2020
Next forecast update: Tuesday, June 30th, 2020

6/26/2020 Forecast Update

FORECAST SUMMARY:

Friday, June 26th, 2020 through Monday, June 29th, 2020

OZONE: 8-Hour average Ozone concentrations will range between Good and Moderate; a few USG readings are possible early next week.

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

FORECAST DISCUSSION:

Strong storms are forecast to move through the state Friday late afternoon through the overnight hours as a cold front drops in from the northwest. This boundary sinks just south of the state Saturday, possibly triggering more showers and storms across southern locations. Sunday into Monday this boundary slowly sinks south into the Ohio valley as high pressure moves over the northern Great Lakes region. Behind this boundary temperatures do not fall and highs above normal are expected as we move into next week.

As for air quality, ozone has been Good the past few days and with clouds moving in I am expecting mostly Good readings again Friday. The boundary drops south Saturday, and temperatures remain warm; however, clouds starting the day and a west/northwesterly wind at the surface and upper levels should keep ozone between Good and low Moderate. The difficulty in the forecast for early next week is the exact placement of the Saturday boundary and how far south it gets.

Models show more in the way of sunshine Sunday while some clouds may linger further south. I am expecting ozone readings to increase from Saturday with most locations into the Moderate range Sunday. By Monday, winds at the surface and upper levels look to become east/southeasterly as high pressure moves northeast of the state. For now, I am going with a Moderate forecast for ozone Monday with a few locations having the possibility to reach USG; mainly along the west Michigan lakeshore if afternoon lake breezes develop. We will evaluate weather maps Sunday morning and will update this forecast if we feel widespread USG levels become a threat for Monday.

Fine particulate has been running mostly Good and levels through early next week will range from middle Good to low Moderate.

EXTENDED FORECAST:

Extended models keep us in the same weather pattern as we continue towards mid-week. Without an airmass change, the warm, dry, sunny conditions will bring a threat for increased ozone. This threat for higher ozone concentrations will be detailed in the Monday forecast update, or Sunday if one is necessary.

Forecast update by: Stephanie M. Hengesbach June 26th, 2020.
Next forecast update: Monday, June 29th, 2020

6/22/2020 Forecast Update

FORECAST SUMMARY:

Monday, June 22nd, 2020 through Friday, June 26th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Low Moderate to Moderate on Monday, then generally Good to Low Moderate through the remainder of the work week.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good through the week.

FORECAST DISCUSSION:

Last week, we experienced more USG readings across the state than all of 2019, combined.  Any help that the lockdowns may have had, earlier in the ozone season, appear to have disappeared. 

Fortunately, this week should be a reprieve from the poor Air Quality of last week.  Although we remain in the same air mass during Monday, clouds and shower potential should keep monitor values mostly in check.  I expect Moderates will still rule the day while we remain in this same stagnant air mass.  The reprieve will finally come Tuesday morning with a passage of a cold front which will usher in new cooler and cleaner air mass.

This cooler and cleaner air mass will provide daily highs in the 70’s for most of the remainder of the work week and vastly improved Air Quality over last week.  However, since we are in that time of the year with the longest daylight hours and strongest solar radiation, this forecast will be updated on Friday.

EXTENDED FORECAST:

Air Quality should remain Good to Low Moderate into the weekend.

Forecast updated by Jim Haywood: Monday, June 22nd, 2020
Next forecast update: Friday, June 26th, 2020

6/20/2020 Forecast Update

FORECAST SUMMARY:

Saturday, June 20th, 2020 through Monday, June 22nd, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate and USG Saturday with levels ranging between Good to Moderate Sunday and Monday

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to low Moderate.

AN ACTION DAY ADVISORY IS IN EFFECT FOR SATURDAY FOR THE FOLLOWING MICHIGAN COUNTIES...

IN WEST MICHIGAN:

ALLEGAN... BENZIE… BERRIEN… CASS… GRAND TRAVERSE... KALAMAZOO… KENT... LEELANAU… MANISTEE… MUSKEGON… OCEANA… OTTAWA… MASON… ST. JOSEPH… AND VAN BUREN

IN SOUTHEAST MICHIGAN:

GENESEE… LAPEER… LIVINGSTON… MACOMB… MONROE… OAKLAND… ST. CLAIR… WASHTENAW… AND WAYNE

FORECAST DISCUSSION:

Another warm day with increased ozone was seen Friday and one more day of similar conditions is expected Saturday. Ozone will range from Moderate to USG as plenty of sunshine remains, along with increased surface and upper level temperatures. Because of this, we have an Air Quality Action Day Advisory in place for Saturday for the counties listed above. By Sunday, clouds associated with an approaching boundary, along with chances for scattered storms, will help keep ozone from increasing like we have experienced this week. Ozone on Sunday is not expected to reach higher than Moderate. While there is a very small chance for a monitor or two may reach low-end USG, the threat is not high enough to warrant an action day on Sunday.

Much of the same is expected Monday, warmer temperatures linger and a boundary over the region will trigger scattered storms. There again is a threat for isolated USG levels, but I feel clouds will keep readings in the Moderate range. I will evaluate maps Sunday morning and if my thoughts on Mondays forecast changes, I will send an update.

Fine particulate has been running mostly Moderate and levels will remain generally Moderate through Monday.

EXTENDED FORECAST:

Models show a stronger front passing the state Tuesday which will bring northwesterly winds, cooler temperatures, and cleaner air in its wake. Air Quality by Tuesday/Wednesday should be back to the Good range.

Forecast Updated by Stephanie M. Hengesbach June 20th, 2020
Next forecast update: Monday, June 22nd, 2020

6/19/2020 Forecast Update

FORECAST SUMMARY:

Friday, June 19th, 2020 through Saturday, June 20th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate and USG Friday and Saturday; Air Quality Air Advisories are in place for both days.

PM-2.5: 24-hour average Fine Particulate concentrations will be mostly Moderate through the weekend.

AN ACTION DAY ADVISORY IS IN EFFECT FOR FRIDAY AND SATURDAY FOR THE FOLLOWING MICHIGAN COUNTIES...

IN WEST MICHIGAN:

ALLEGAN... BENZIE… BERRIEN… CASS… GRAND TRAVERSE... KALAMAZOO… KENT... LEELANAU… MANISTEE… MUSKEGON… OCEANA… OTTAWA… MASON… ST. JOSEPH… AND VAN BUREN

IN SOUTHEAST MICHIGAN:

GENESEE… LAPEER… LIVINGSTON… MACOMB… MONROE… OAKLAND… ST. CLAIR… WASHTENAW… AND WAYNE

FORECAST DISCUSSION:

Moderates and USG levels were again seen Thursday and higher readings are expected to continue into the weekend. Michigan remains under the same air mass this weekend and both temperatures and humidity will increase. Considering weather conditions remain conducive for ozone development as we go into the weekend, we are extending the Air Quality Action Day Advisory currently in place to also cover Saturday.

By Saturday, a frontal boundary will be approaching from the west. Southwesterly winds aid to increase temperature and humidity. One factor against increasing ozone may be a bit more clouds over the area. USG ozone concentrations may not be as widespread Saturday, however, there is still enough threat for USG to keep the Action Day Advisory in place.

Models seem to be slowing precipitation changes for later Saturday into Sunday and the boundary coming through will do little to give us a clean out after it passes. With the uncertainty in the current models, we will be evaluating forecast maps tomorrow morning to determine with better certainty that pollution levels will improve Sunday.

EXTENDED FORECAST:

Air Quality should remain Moderate to USG going into the weekend.

Forecast updated by Stephanie M. Hengesbach June 19th, 2020
Next forecast update: Saturday, June 20th, 2020

6/18/2020 Forecast Update

FORECAST SUMMARY:

Thursday, June 18th, 2020 through Friday, June 19th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate and USG during Thursday and Friday.  Both days have Air Quality Air Advisories.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderates through the week.

AN ACTION DAY ADVISORY IS ISSUED FOR FRIDAY FOR THE FOLLOWING MICHIGAN COUNTIES...

ALLEGAN...  BENZIE…  BERRIEN…  CASS…  GRAND TRAVERSE...  KALAMAZOO…  KENT...  LEELANAU… MANISTEE…  MUSKEGON...  OCEANA… OTTAWA…    MASON…  St. JOSEPH…  AND VAN BUREN COUNTIES IN WEST MICHIGAN; AND

GENESEE…  LAPEER…  LIVINGSTON…  MACOMB…  MONROE…  OAKLAND… ST. CLAIR…  WASHTENAW…  AND WAYNE COUNTIES IN SOUTHEAST MICHIGAN

FORECAST DISCUSSION

Moderates and USG levels dominated the Air Quality map during Wednesday.   I was a bit surprised as to how quickly some of the monitors jumped into the low USG level after starting the day with relatively low concentrations.   That reinforces the decision to issue air advisories for Thursday.  As conditions can only get worse, we will be continuing advisories into Friday and expanding the list of counties.

We remain under the same air mass with increasing temperatures and humidity.  Air pollutants are accumulating because they have nowhere to go and the high pressure dome are keeping them suppressed at the surface.

We will not be out of the woods after Friday as we will be in the same air mass through the weekend.  However, there may be some clouds and showers during the weekend in advance of a frontal passage Monday or Tuesday.  If that occurs, it would help keep concentrations down but it may not be widespread enough to really make a difference.  The Friday forecast will shed more light on that.

EXTENDED FORECAST:

Air Quality should remain Moderate to USG going into the weekend.

Forecast updated by Jim Haywood: Thursday, June 18th, 2020
Next forecast update: Friday, June 19th, 2020

6/17/2020 Forecast Update

FORECAST SUMMARY:

Wednesday, June 17th, 2020 through Thursday, June 18th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate on Wednesday transitioning to Moderate and USG on Thursday.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderates through the week.

AN ACTION DAY ADVISORY IS ISSUED FOR THE FOLLOWING MICHIGAN COUNTIES for THURSDAY...

IN WEST MICHIGAN:

ALLEGAN, BERRIEN, CASS, KENT, MUSKEGON, OCEANA, OTTAWA, MASON, AND VAN BUREN COUNTIES.

FORECAST DISCUSSION

Tuesday was a mixture of Good and Moderate throughout the state.  This pattern will continue through Wednesday with a possibility of isolated USG’s as air pollutants continue to accumulate under the same air mass.

Each day, this week, has gotten progressively worse as temperatures and humidity slowly increase and air pollutants accumulate.  As such, I am issuing an Air Quality Advisory in both Southeast and West Michigan for Thursday.  There is a good chance that this will carry over into Friday, but we will make that call on Thursday after reviewing the latest computer model runs.

There is a chance for scattered precipitation on Saturday, but we will not see a change in air mass until early next week. 

EXTENDED FORECAST:

Air Quality should remain mostly Moderate to USG to the end of the work week.

Forecast updated by Jim Haywood: Wednesday, June 17th, 2020
Next forecast update: Thursday, June 18th, 2020

6/16/2020 Forecast Update

FORECAST SUMMARY:

Tuesday, June 16th, 2020 through Wednesday, June 17th, 2020

OZONE: 8-Hour average Ozone concentrations will be mixture of Good and increasing Moderates through Wednesday with decreasing Air Quality by the end of the week.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderates through the week.

FORECAST DISCUSSION

Monday was a sunny, dry day with Air Quality concentrations in the Good category throughout the state.  Tuesday will be continuation under the same dome of high pressure with slowly warming temperatures and dew points.  As such, I think Tuesday will remain mostly Good and some Moderates expected in Southeast Michigan and the western lake shore.

Wednesday will more of a ramp-up day as temperatures and humidity continue to increase under the same air mass.  Several of the models are holding down Wednesday temperatures to around the 80 degree with upper air temperature also remaining on the cooler side.  This scenario would keep Air Quality a mixture of Good and Moderates.  Other models have it warming up several degrees more and that could yield worsening Air Quality if that pans out.  Right now, I am on the side of the fence that gives us a mixture of Good and Moderates.

Thursday and Friday will likely be more interesting as we remain under the same air mass, pollutants accumulate, and temperatures/humidity increase.  The model results for those days are also differing on surface and upper air temperature and will require close monitoring.  Therefore, I intend to update this forecast Wednesday morning once the latest model runs are out.

EXTENDED FORECAST:

Air Quality should remain mostly Good with increasing Moderates by midweek, and declining Air Quality by the end of the work week.

Forecast updated by Jim Haywood: Tuesday, June 16th, 2020
Next forecast update: Wednesday, June 17th, 2020

6/15/2020 Forecast Update

FORECAST SUMMARY:

Monday, June 15th, 2020 through Tuesday, June 16th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Good through Tuesday with decreasing Air Quality through the end of the week.

PM-2.5:  24-hour average Fine Particulate concentrations will be mostly Good to Low Moderates through the week.

FORECAST DISCUSSION

Dry weather and mostly clear skies are expected through the end of the work week.  Monday morning starts off cool with afternoon highs nearing 80 degrees under light easterly winds and dew points in the upper 40’s.  Upper air temperatures remain cool which should help maintain Good Air Quality through Monday.  This pattern should persist through Tuesday with slightly higher temperatures and dew points.  Air Quality should generally stay in the Good category but some areas in southeast Michigan may reach Low Moderate during Tuesday.

The real warmup begins on Wednesday when surface temperatures are expected to reach the mid-80’s.  Upper air temperatures are still a bit on the cool side, which should help subdue ozone numbers, but the long daylight hours and strong sun may start pushing numbers towards the USG mark, in certain areas.

The hottest days will likely occur on Thursday and Friday when afternoon temperatures in the upper 80’s and the dew points near 60 are expected.  Upper air temperatures are still not optimal for ozone development, but the long days and strong sun may dominate ozone development near the surface. 

Having already seen a couple of days with decent ozone development in the past two weeks, I think it will be smart to keep a daily watch on developing situations.  As such, this forecast will be updated, tomorrow, and likely each day this week.

EXTENDED FORECAST:

Air Quality should remain mostly Good early in the week, with Moderates by midweek, and declining Air Quality by the end of the work week.

Forecast updated by Jim Haywood: Monday, June 15th, 2020
Next forecast update: Tuesday, June 16th, 2020

6/12/2020 Forecast Update

FORECAST SUMMARY:

Friday, June 12th, 2020 through Monday, June 15th, 2020

OZONE: 8-Hour average Ozone concentrations will generally be Good with some Moderates possible Monday.

PM-2.5: 24-hour average Fine Particulate concentrations will range from Good to low Moderate by Monday.

FORECAST DISCUSSION:

Scattered showers are a possibility Friday as a weak boundary sinks through the state; however, most locations remain dry. For the rest of the week/weekend, cool high pressure will be in place with plenty of sunshine but expect below normal temperatures.

As for air quality, cool surface and upper level temperatures coupled with a northerly, then easterly, component to the wind should keep both ozone and fine particulate generally Good through Sunday.

By Monday, high pressure slides east, and winds change to more of a southeasterly direction. Temperatures rebound to normal levels, but I feel cooler upper levels temperatures will hamper a significant increase in ozone, especially coming off a low background from the weekend. Ozone and fine particulate should both be in the upper Good to low Moderate range Monday.

EXTENDED FORECAST:

Extended forecast models show increasing temperatures into mid-week with southwesterly winds developing by Tuesday. Pollution levels past Monday likely increase into the Moderate range, but this will be detailed in the Monday forecast update.

Forecast update by Meteorologist Stephanie M. Hengesbach June 12th, 2020
Next forecast update: Monday, June 15th, 2020