8/14/2020 Forecast Update

FORECAST SUMMARY:

Friday, August 14th, 2020 through Monday, August 17th, 2020

OZONE: 8-Hour average Ozone concentrations will be a mix of Good and Moderate through Saturday, then Good though Monday.  

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

FORECAST DISCUSSION

The ridge of high pressure that has brought us sun and warm temperatures during the week will finally break down and shift eastward Friday afternoon.  In its wake will be a weak low pressure trough moving through the Ohio Valley and a stronger front projected Saturday night.

The weaker of the two systems could bring some convective activity, later Friday afternoon, but residual atmospheric stability from the exiting high pressure, plus the lateness of the day, will likely keep that to a minimum.

The stronger system, Saturday night, could also kick off some convective activity but likely not widespread.

Air Quality during Friday and Saturday should remain in the Good to Moderate range with the mixture of broken clouds and potential shower activity.

A good clean-out will occur behind the front, on Sunday, and the new week should start in the Good category.

EXTENDED FORECAST:

Air Quality should be Good going into next week.

Forecast updated by Jim Haywood: Friday, August 14th, 2020
Next forecast update: Monday, August 17th, 2020

8/10/2020 Forecast Update

FORECAST SUMMARY:

Monday, August 10th, 2020 through Friday, August 14th, 2020

OZONE: 8-hour average Ozone concentrations will range from Good to Moderate through the forecast period.

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

FORECAST DISCUSSION:

Warm conditions are in store this week. A cold front later Monday/early Tuesday will bring storms in the forecast. Precipitation should exit early Tuesday, but northerly winds will not significantly drop temperatures; highs in the 80s can be expected through the rest of the week under generally sunny skies.

As for air quality, several monitors reached Moderate for ozone Sunday and that trend will likely continue Monday. After the boundary moves through, high pressure both at the surface and upper levels will dominate the rest of the workweek. A northerly component to the wind should keep ozone Good Tuesday. Winds are light at mid-week then turn east/southeast as ridging moves east of the region. The expected wind flow this week is not conduce for ozone development; however, warmer surface and upper level temperatures, coupled with no airmass change, could cause Moderate ozone to develop by Thursday or Friday.

Fine particulate has been between upper Good and low Moderate since Sunday and levels in that range will persist until the boundary passes Tuesday. Like ozone, Good fine particulate levels at mid-week could increase back to low Moderate by Thursday or Friday.

EXTENDED FORECAST:

There is some uncertainty on when the next chance for precipitation moves into the region. Extended models are showing chances for storms during the weekend, but there is enough uncertainty in the forecast that we will issue an update Friday to detail anticipated air quality conditions for the weekend, into next week.

Forecast Updated by: Stephanie M. Hengesbach August 10th, 2020.
Next forecast update: Friday, August 14th, 2020

8/7/2020 Forecast Update

FORECAST SUMMARY:

Friday, August 7th, 2020 through Monday, August 10th, 2020

OZONE: 8-Hour average Ozone concentrations will be mostly Moderate through the weekend period with a slight chance of isolated USG during Saturday and Monday.  

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

FORECAST DISCUSSION

The weekend weather will be a return to more typical summer weather with temperatures rising back into the upper 80’s with increasing humidity. With this shift, Air Quality will likely begin slowly degrading.  The question will be if we could reach the USG levels.

The past two weeks have yielded Good Air Quality.  As the current high pressure system moves off to the east during Friday, winds will begin a shift to the south and southwest.  With that shift, air pollutants from Illinois and Indiana will drift over Lake Michigan and can impact the lake shores.  Current ozone models are keeping the highest concentrations over the lake and more towards the Wisconsin shore.

The Saturday forecast is pretty straight-forward with a mix of Good and Moderate.  Sunday and Monday have increasing temperatures and humidity, but chances also increase for shower activity as a short-wave of low pressure passes through Sunday morning with a stronger front projected to pass Monday night.

With the potential clouds and shower activity, ozone production should be reduced enough to ward off any widespread USG.  As such, I anticipate this forecast should be sufficient to get us through Monday morning.  However, if conditions do deteriorate enough, we will update this weekend forecast, as necessary.

EXTENDED FORECAST:

Air Quality should be a mix of Good and Moderate going into next week.

Forecast updated by Jim Haywood: Friday, August 7th, 2020
Next forecast update: Monday, August 10th, 2020

8/3/2020 Forecast Update

FORECAST SUMMARY:

Monday, August 3rd, 2020 through Friday, August 7th, 2020

OZONE: 8-hour average Ozone concentrations will be mostly Good with Moderates possible Friday.

PM-2.5: 24-hour average Fine Particulate concentrations will be mostly Good with a few low Moderates, mainly in the southeast.

FORECAST DISCUSSION:

Clouds and chances for precipitation are in the forecast Monday and Tuesday thanks to upper level disturbances moving through the region. High pressure at mid-week will dry conditions and provide cooler than normal temperatures for a couple days. Warmer conditions look to move in for the end of the week and into the weekend.

As for air quality, weather conditions will not be conducive for ozone development through Wednesday; therefore, mostly Good ozone is expected. High pressure overhead will produce plenty of sunshine by Thursday and temperatures warm closer to 80 on Friday. Lighter winds turning southerly could allow for Moderate ozone in some locations Thursday and/or Friday.

By Saturday, winds pick up from a southerly direction and both surface and upper level temperatures increase. Weather conditions turn more conducive for ozone development by the weekend so we will update the forecast Friday to detail any potential increase for the weekend into early next week.

Fine particulate through mid-week will continue mostly Good with only a few locations in the southeast possibly averaging low-Moderate for the day. Like ozone, by the end of the week a few more Moderate levels are possible.

EXTENDED FORECAST:

Extended forecast maps show warmer temperatures into early next week, but what is uncertain is a possibility of storm activity. More details on the extended forecast will be posted Friday.

Forecast updated by Meteorologist Stephanie M. Hengesbach August 3rd, 2020.
Next forecast update: Friday, August 7th, 2020

7/27/2020 Forecast Update

FORECAST SUMMARY:

Monday, July 27th, 2020 through Monday, August 3rd, 2020

OZONE: 8-Hour average Ozone concentrations will be Good to Low Moderate through the forecast period.  

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

FORECAST DISCUSSION:

The work week starts with a slow-moving cold front which could kick off shower activity during Monday.  The clouds and shower activity will keep Air Quality in the Good range through the day.

The remainder of the forecast period should be the closest thing to a ‘normal’ summer weather week that we have seen in a while.  Temperatures should stay in the lower 80’s, dew points comfortably dryer, and skies mostly rain-free.  The wind patterns for the week will not feature any southwest winds, which can be so damaging to our Lake Michigan shoreline, and mostly clean-source wind directions to help Southeast Michigan.  Winds do go calm, at the end of the work week, so we may see a brief period of stagnation creep in the urban areas but that should be short-lived. 

So, for the first time in many weeks, I think we are comfortable going until Monday for our next forecast update.

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Monday, July 27th, 2020
Next forecast update: Monday, August 3rd, 2020

7/24/2020 Forecast Update

FORECAST SUMMARY:

Friday, July 24th, 2020 through Monday, July 27th, 2020

OZONE: 8-hour average Ozone concentrations will range from Good to Moderate through Sunday, with Good readings Monday.

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

FORECAST DISCUSSION:

Sunny conditions Friday will make a pleasant day, and easterly winds hamper any pollution build up. On Saturday, southwesterly winds develop as high pressure moves east of the region. Temperatures at the surface and upper levels will increase, along with humidity levels. A frontal boundary moves in Sunday bringing chances for precipitation from northwest to southeast as the day progresses. Precipitation chances linger into Monday as the boundary sinks southeast.

As for air quality, Good conditions have been in place and we are starting Friday with a clean background. Easterly winds at the surface and upper levels should keep ozone from increasing much; readings will range from Good to low Moderate. Winds become more conducive for ozone development Saturday, but with coming off such a low background we do not expect levels higher than upper Moderate.

While we don’t feel the threat for elevated ozone is high enough this weekend to warrant Action Days, there is a small chance that a monitor or two Saturday will increase faster than anticipated reaching low-end USG. If this happens it would most likely be along the lakeshore of west Michigan and/or in the southeast upwind of the Detroit area.

With the current timing of the front, increasing clouds Sunday and precipitation moving in as the day progresses should keep ozone from reaching higher than Moderate. If the front slows down keeping mostly sunny skies during the day, then there is a possibility for isolated USG readings in the southwest and/or southeast. Even without an Action Day, we will update the AirNow forecast to USG Saturday or Sunday mornings if we feel the USG threat becomes higher than anticipated.

Fine particulate has been Good most of this week. Good levels will linger Friday with a mix of Good to low Moderate expected until the front passes Monday.

EXTENDED FORECAST:

Northwesterly winds develop Monday after the cold front passes. The cooler, cleaner air will produce Good air quality early next week.

Forecast updated by Stephanie M. Hengesbach
Next forecast update: Monday, July 27th, 2020

7/20/2020 Forecast Update

FORECAST SUMMARY:

Monday, July 20th, 2020 through Friday, July 24th, 2020

OZONE: 8-Hour average Ozone concentrations will be Good to Low Moderate through the work week.  

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

FORECAST DISCUSSION

Nobody will deny that this has been a very active summer, both in extreme temperatures and Air Quality.  Fortunately, it looks like this week will be a break in the action.

Looking at the monitor readings, Monday morning, we are seeing low readings which should stay low through the early part of the week.  Mid-week looks to stay low, as well, as a result of a warm front moving through late Tuesday and an associated cold front during Wednesday.  Northwest winds behind the front will provide another clean-out on Thursday.

The warmer temperatures start moving back in during Friday to set up a toasty weekend.  Friday should stay within the Good to Moderate range, so I am not anticipating another forecast update until Friday morning.

EXTENDED FORECAST:

Air Quality should be mostly Good to Low Moderate going into the weekend.  We could see a rise in ozone during the weekend.

Forecast updated by Jim Haywood: Monday, July 20th, 2020
Next forecast update: Friday, July 24th, 2020

7/17/2020 Forecast Update

FORECAST SUMMARY:

Friday, July 17th, 2020 through Monday, July 20th, 2020

OZONE: 8-hour average Ozone concentrations will be mostly Moderate Friday and Saturday with a chance for USG, especially Saturday. Levels will be Good to Moderate Sunday and Monday.

PM-2.5: 24-hour average Fine Particulate concentrations will range from upper Good to low Moderate Friday and Saturday with mostly Good concentrations Sunday and Monday.

AN AIR QUALITY ACTION DAY ADVISORY IS ISSUED FOR SATURDAY JULY 18th 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 are expected as we come to the end of the week, and humidity levels will be quite high Saturday. A cold front passes the state Sunday with associated showers and storms expected late Saturday and Sunday ahead of and along the boundary. Conditions dry out Sunday behind the front and northerly winds should produce Good air quality early next week.

Until then, sunny skies coupled with south/southwesterly winds and warm temperatures both at the surface and upper levels will allow ozone to climb Friday. We are coming off a low background, so we are expecting most locations to be Moderate for ozone. But there is a chance a monitor or two could rise faster than anticipated reaching low-end USG along the western shore of Lake Michigan and/or in the southeast.

On Saturday, south/southwest winds increase in speed bringing in higher humidity; heat indices will approach 100 degrees across parts of the state. Mostly sunny skies continue, especially in the southeastern portion of the state. We will have another day of warm surface and upper level temperatures and ozone is expected to reach higher than the Friday increase. With the projected forecast, we feel there is enough threat for USG ozone Saturday to warrant issuing an Air Quality Action Day across the western lakeshore and in the southeast. What could prevent elevated ozone Saturday would be a very small chance for afternoon storm development, especially in the west. We do not feel this risk is high enough to not issue the action day, but any storm development would likely keep ozone from reaching USG.

Fine particulate may increase into the Moderate range Friday and/or Saturday with generally Good concentrations Sunday and Monday.

EXTENDED FORECAST:

Air Quality readings improve Sunday behind the front. Good ozone Sunday could reach into the Moderate range on Monday, but we do not anticipate elevated ozone early next week. If our thoughts on that changes, we will send a forecast update.

Forecast Updated by Stephanie M. Hengesbach July 17th, 2020.
Next forecast update: Monday, July 20th, 2020

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