09/13/2019 Forecast Update

FORECAST SUMMARY:

Friday, September 13th, 2019 through Monday, September 16th, 2019

Ozone: 8-hour Ozone concentrations will be mostly Good.

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

FORECAST DISCUSSION:

Showers and storms are in the forecast Friday as a cold front passes west to east across the state. High pressure builds on Saturday, but a weak system Sunday will bring small chances for precipitation. Conditions dry out Monday with highs in the 70s. Forecast models are showing a warm-up as next week progresses.

As for air quality, clouds and precipitation will keep ozone Good Friday. Gusty west winds Saturday behind the front will allow Good ozone to continue. The Good trend for ozone should linger early next week as northerly winds at the surface and upper levels arrive following the Sunday disturbance.

Without a prolonged period of stagnation through early next week fine particulate should remain mostly Good. The only exception would be a few low-Moderates possible in the southeast on Friday, then again Sunday and Monday.

EXTENDED FORECAST:

Extended models show dry conditions through mid-week next week with temperatures increasing as ridging builds over the region. Sunshine and warmer temps could allow for some Moderate pollution to develop.

Next forecast update: Monday, September 16th, 2019

09/09/2019 Forecast Update

FORECAST SUMMARY:

Monday, September 9th, 2019 through Friday, September 13th, 2019

Ozone: 8-hour Ozone concentrations will be mostly Good, but Moderates are a possibility across the south.

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

FORECAST DISCUSSION:

Cloudy, cool conditions Monday will be replaced with warm summer-like temperatures starting Tuesday, especially in southern and central portions of the state. The weather change occurs as a low tracks west to east just north of Lake Superior pulling warm front north late Monday into Tuesday. This boundary then sinks back south becoming positioned somewhere across lower Michigan through Thursday. A stronger cold front passing Friday will bring back cooler conditions.

As for air quality, temperatures at the surface and upper levels will increase Tuesday through Thursday as winds turn to a more ozone conducive direction, from the southwest/west. However, at least some clouds and chances for precipitation exist each day. Also, considering the lower sun angle this time of year increased ozone is harder to attain. There is enough concern for Moderate levels across the south that  Moderate will be forecasted in those areas. Any Moderate readings will improve to Good Friday as a cold front brings in a cooler, cleaner air mass.

With a boundary positioned nearby, fine particulate may increase over the next few days. Levels are expected to range from upper Good to low Moderate until Friday when readings return to Good statewide.

EXTENDED FORECAST:

Extended models show high pressure moving in for the end of the week and another warm-up looks possible early next week. While the chances for USG ozone are not high, we will evaluate weather conditions Friday to better detail expected air quality levels for the weekend into early next week.

Next forecast update: Friday, September 13th, 2019

09/03/2019 Forecast Update

FORECAST SUMMARY:

Tuesday, September 3rd, 2019 through Monday, September 9th, 2019

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

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

FORECAST DISCUSSION

Tuesday through early Wednesday will be a bit unsettled as an active weather system moves through the Midwest.  Air Quality should remain Good with ample clouds and high probability of precipitation.

High pressure follows later Wednesday and will dominate the remainder of Wednesday and into early Thursday.  Northerly wind flow will provide sunny skies, cooler temperatures and Good Air Quality. 

Temperatures should warm a bit late Thursday into Thursday night in advance of a small system which is expected to pass Friday morning.  Light winds and stagnating air could produce some Low Moderates during Thursday afternoon and Friday in southeast Michigan but I expect mostly Good elsewhere.

High pressure returns for the weekend with mostly northerly air flow and Good Air Quality.  Shifting winds to the east-northeast are likely during Monday with little chance of Air Quality issues.

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Tuesday, September 3rd, 2019
Next forecast update: Monday, September 9th, 2019

08/30/2019 Forecast Update

FORECAST SUMMARY:

Friday, August 30th, 2019 through Tuesday, September 3rd, 2019

Ozone: 8-hour Ozone concentrations will be mostly Good through the forecast period with Moderates possible Tuesday.

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

FORECAST DISCUSSION:

Cool, quiet conditions will start the holiday weekend as high pressure settles in and remains in place through Sunday. An upper level systems could bring scattered precipitation late Saturday/early Sunday and again Monday, but these do not look like widespread rain events. Warmer conditions move in Tuesday ahead of a cold front which is expected to pass through later in the day. The big weather story this weekend, however, is hurricane Dorian which is expected to make landfall in Florida early next week.

As for air quality, through Monday a predominant northwesterly flow remains in place. Cooler temperatures and some clouds should keep ozone mostly Good. Warmer surface and upper level temperatures move in Tuesday with southwesterly winds increasing, especially across the southern portion of the state. Weather conditions Tuesday do look a bit conducive for ozone development across the south, but we will be coming off a low background of levels. Also, earlier sunset this time of year and clouds moving in will aid in keeping conditions from reaching higher than Moderate. Weather conditions will be evaluated during the weekend and if needed, the forecast will be updated.

Without much of a stagnant period though early next week, any significant build-up of fine particulate is not anticipated. Readings should remain mostly Good.

EXTENDED FORECAST:

Extended models show high pressure and cooler conditions by midweek next week. Air quality should be Good during this period.

Next forecast update: Tuesday, September 3rd, 2019

08/26/2019 Forecast Update

FORECAST SUMMARY:

Monday, August 26th, 2019 through Friday, August 30th, 2019

Ozone: 8-hour Ozone concentrations will be mostly Good through the forecast period.

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

FORECAST DISCUSSION:

Rain develops Monday, continuing into Tuesday as a system moves through. A weaker boundary passes later Wednesday, and another on Friday, but the best chance for precipitation will be early in the week. High pressure then builds in for the Holiday weekend.

As for air quality, clouds and precipitation should keep air quality Good Monday and Tuesday. The exception may be the southwest corner of the state on Tuesday. Moderate ozone is a possibility if clouds clear out early in the day. This is shown on some forecast models so the forecast is Moderate in that part of the state to cover the threat. Good ozone is expected Wednesday, but levels could reach Moderate at a few locations on Thursday thanks to plenty of sunshine and seasonable surface temperatures. By Friday, high pressure brings cooler surface and upper level temperatures on a northwesterly flow; this upper level flow remains in place through Sunday keeping ozone mostly Good. Temperatures increase some Monday as high pressure moves east of the state; a few areas may see low Moderates for ozone.

Without much of a stagnant period though the week a significant build-up of fine particulate is not anticipated. Readings should remain mostly Good.

EXTENDED FORECAST:

Extended models show southwest winds and warmer temperatures by Tuesday of next week. It’s too soon to tell if there is a chance for increased pollution, however, this forecast will be updated Friday to detail expected air quality conditions through the Holiday weekend, into next Tuesday.

Next forecast update: Friday, August 30th, 2019
Forecast by: Stephanie M. Hengesbach

08/19/2019 Forecast Update

FORECAST SUMMARY:

Monday, August 19th, 2019 through Monday, August 26th, 2019

Ozone:  8-Hour average Ozone concentrations will be mostly Good to Moderate during Monday and Tuesday, then mostly Good through the remainder of the forecast.

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

FORECAST DISCUSSION

Monday and Tuesday will be seasonal with temperatures in the mid-to-upper 80’s with increasing humidity.  High pressure builds in during Monday and should persist through Tuesday.  Any chance for some creep in ozone concentrations, during this forecast period, should occur during these two days as light winds become more southwesterly during Tuesday.  Although ozone is expected to begin inching up, there is no compelling evidence that we will get into the USG range during Tuesday although concentrations are expected to get up in the High Moderate range.  However, the shorter days of late summer should work in our favor.

A cold front is projected to pass through the region Tuesday night into Wednesday.  The cooler, dryer air mass that follows the front should keep us solidly in the Good category through the remainder of the work week.  Forecasters are seeing a bit of a warm up during the weekend as winds shift around to the southeast, but nothing is indicating a buildup of ozone to anything worse than Low Moderate. 

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Monday, August 19th, 2019
Next forecast update: Monday, August 26th, 2019

08/16/2019 Forecast Update

FORECAST SUMMARY:

Friday, August 16th, 2019 through Monday, August 19th, 2019

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

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

FORECAST DISCUSSION:

Systems will bring on and off chances for precipitation through the weekend. The first chance will be Friday evening/night; Saturday should be mostly dry; but precipitation chances return Sunday. A stronger front moves through later Monday/Tuesday cooling conditions down by mid-week.

As for air quality, seasonable surface temperatures, coupled with cooler upper level temperatures and at least scattered cloud cover, will keep ozone from reaching higher than Moderate Friday or Saturday. By Sunday, surface and upper level temperatures increase along with dew point readings. Clouds and precipitation associated with a system nearby should again keep ozone from reaching higher than Moderate. Less cloud cover is expected Monday with warmer temperatures continuing; however, the system passing through Sunday should allow for more northerly/westerly winds. Currently, ozone is not expected to get higher than Moderate on Monday.

Significant build-up of fine particulate is not anticipated. Readings should range from middle Good to low Moderate.

EXTENDED FORECAST:

Extended models show cooler conditions by mid-week allowing for Good air quality.

Next forecast update: Monday, August 19th, 2019

08/12/2019 Forecast Update

FORECAST SUMMARY:

Monday, August 12th, 2019 through Friday, August 16th, 2019

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

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

FORECAST DISCUSSION:

A frontal boundary and associated low pressure area will bring precipitation in the forecast later Monday into Tuesday. Then, a second weaker system could trigger scattered precipitation later Wednesday. These systems should keep ozone primarily Good through mid-week. Northerly winds at upper levels then keep cooler temperatures around through Friday. Conditions dry out Thursday and Friday, but lower temperatures will keep ozone from increasing higher than a few Moderates. Moderate fine particulate in the southeast Monday into Tuesday will likely improve to Good by Wednesday, lasting through Friday.

EXTENDED FORECAST:

Extended models are hinting at a warmup for the coming weekend which could make increased ozone a possibility. There is a bit on uncertainty; therefore, this forecast will be updated Friday to detail weekend air quality conditions.

Next forecast update: Friday, August 16th, 2019

08/05/2019 Forecast Update

FORECAST SUMMARY:

Monday, August 5th, 2019 through Monday, August 12th, 2019

Ozone:  8-Hour average Ozone concentrations will be a mostly Good and Low Moderate for the first half of the week then mostly Good through the weekend.

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

FORECAST DISCUSSION

The first half of the forecast period will feature some active weather patterns followed by cooler, clear weather for the weekend.

As high pressure over the region moves eastward during Monday, it is making way for a trough of low pressure to advance from the west.  There is a chance of a few isolated pop-up storms Monday afternoon ahead of a cold front.  But the better chance of storms will occur Monday night and Tuesday morning as the cold front punches through.  Air Quality should range from Good to Low Moderate on Monday.  Air Quality should be Good on Tuesday.

Another cold front is expected to pass Wednesday night into Thursday morning.  Wednesday’s Air Quality should range between Good and Low Moderate in advance of this frontal passage and Good once it passes/.

The air mass following this front will be cool and dry with sunny daytime high temperatures around 80 and clear nighttime lows around 60.  This should persist through the weekend with Good Air Quality.

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Monday, August 5th, 2019
Next forecast update: Monday, August 12th, 2019

08/02/2019 Forecast Update

FORECAST SUMMARY:

Friday, August 2nd, 2019 through Monday, August 5th, 2019

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

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

FORECAST DISCUSSION:

Mainly dry conditions persist this weekend with only small chances for precipitation in association with a weak boundary dropping south Saturday. The next larger chance for precipitation comes into play late Monday/Tuesday as a stronger front passes through. For the most part expect seasonable, dry conditions through Sunday.

As for air quality, upper level northerly winds and cooler temperatures have kept ozone Good. With this flow persisting through the weekend, we don’t expect ozone to reach higher than Moderate. More of a southwesterly surface flow develops Monday ahead of the approaching boundary, but upper level temperatures remain low and northerly even as surface temperatures increase. Higher than Moderate ozone will not likely be seen Monday, but if this changes the forecast will be updated Sunday morning.

Fine particulate has also been Good, and a significant increase isn’t expected over the next few days. Readings should range from middle Good to low Moderate.

EXTENDED FORECAST:

Extended models show a cool down for next week after the Tuesday front passes…air quality will be Good for both ozone and fine particulate.

Next forecast update: Monday, August 5th, 2019

07/29/2019 Forecast Update

FORECAST SUMMARY:

Monday, July 29th, 2019 through Friday, August 2nd, 2019

Ozone: 8-hour Ozone concentrations will be mostly Good through mid-week, then a mix of Good and Moderates are expected.

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

FORECAST DISCUSSION:

A cold front passing Monday will bring showers and/or storms. High pressure then moves in Tuesday and forecast models have this high positioned over the Great Lakes region through the end of the week. A small chance for precipitation lingers Tuesday mostly in the east, otherwise, dry conditions, seasonable temperatures, and low humidity’s can be expected.

Clouds and precipitation will keep Ozone Good Monday. Good levels continue Tuesday into Wednesday thanks to northwesterly winds and cooler surface and upper level temperatures. Temperatures will warm at the surface each day past mid-week, but upper level readings remain low through Friday. Ozone could reach Moderate in a few locations, but mostly Good levels should continue.

Fine particulate could also see slow increases starting Thursday, but readings higher than low-Moderate are not anticipated.

EXTENDED FORECAST:

Extended models keep high pressure over the region through early next week. Remaining under the same airmass for a few days could be a set up for increased pollution. At this time readings higher than Moderate are not expected, but this forecast will be updated Friday to better detail air quality conditions through early next week.

Next forecast update: Friday, August 2nd, 2019

Stephanie M. Hengesbach

Meteorologist

Air Quality Division

Michigan Department of Environment, Great Lakes, and Energy

07/22/2019 Forecast Update

FORECAST SUMMARY:

Monday, July 22nd, 2019 through Monday, July 29th, 2019

Ozone:  8-Hour average Ozone concentrations will be a mostly Good for the first half of the week then a mixture of Good and Low Moderate through the weekend.

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

FORECAST DISCUSSION

After a week of hot and humid weather, we will enjoy a cooling down and Good Air Quality.  We can thank a ridge of high pressure currently located over the Plaines states.  While the center of high pressure remains to the west, we will be under a northerly wind profile.  This will yield cooler and drier air through mid-week with Good Air Quality throughout the state.  The only blemish during the first half of the week will be an upper air disturbance Tuesday afternoon which could produce some showers.

The ridge of high pressure will pass through the state early Thursday.  The wind profile on the back side of the high will become more southwesterly.  With the wind shift will come increasing temperatures and humidity for the weekend.  We will be coming off several days of very clean air and any increase in ozone will be slow in developing.

Right now, the regional forecasters do not have much concern about any elevated ozone for this forecast period.  Should it appear that conditions during the upcoming weekend start looking more threatening, the forecast will be updated.

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Monday, July 22nd, 2019
Next forecast update: Monday, July 29th, 2019

07/19/2019 Forecast Update

FORECAST SUMMARY:

Friday, July 19th, 2019 through Monday, July 22nd, 2019

THE CURRENT ACTION DAY ADVISORY IS EXTENDED THROUGH SATURDAY, JULY 20th IN THE FOLLOWING MICHIGAN COUNTIES...

IN WEST MICHIGAN:

BERRIEN…  ALLEGAN...  KENT...  MUSKEGON...  OTTAWA…  VAN BUREN COUNTIES

Ozone:  8-Hour average Ozone concentrations will be a mixture Moderate and USG during Friday and Saturday.  Air Quality should return to Good and Low Moderate for Sunday and Monday. 

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

FORECAST DISCUSSION

The hot, humid weather will continue through Saturday.  With the current high temperatures and humidity, if we get clear skies then elevated ozone potential is very high. 

The big question is how much cloud cover will we see?  During Thursday, cloud cover was enough to keep ozone production in the Moderate range.  As this forecast is being written Friday morning, cloud cover is present but looks to be thinning.  If that trend continues, we could see ozone numbers reaching the USG levels.

The cloud cover question is also an issue for Saturday.  The various forecast models are very inconsistent with their cloud forecast.  Some of the models have significant cloud cover for Saturday while others keep it mostly clear until late afternoon.  Knowing that clear skies would lead to high ozone concentrations, to err on the side of caution the current Action Day Advisories will be extended through Saturday.  

The threat will end on Sunday following a cold front passage Saturday night.

EXTENDED FORECAST:

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

Forecast updated by Jim Haywood: Friday, July 19th, 2019
Next forecast update: Monday, July 22nd, 2019

07/18/2019 Forecast Update

FORECAST SUMMARY:

Thursday, July 18th, 2019 through Friday, July 19th, 2019

...AIR QUALITY ACTION DAY ADVISORIES FOR THURSDAY JULY 18TH AND FRIDAY JULY 19TH...

IN WEST MICHIGAN:

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

Ozone: 8-hour Ozone concentrations will range between Good and Moderate with a threat for USG in the west and southeast.

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

FORECAST DISCUSSION:

The easy part of the forecast is the fact that hot, humid conditions can be expected through Saturday with heat indices reaching over 100 degrees in several locations. The difficult part of the forecast is determining when and where storm complexes may develop the next few days.

A storm complex Thursday traveling west to east across southern Lower Michigan was expected to be further north. We currently have Action Days in place across southwest and southeast Michigan since yesterday’s models were showing dryer conditions with plenty of sunshine. The storms may hamper ozone from reaching USG today; but, if the sun breaks out after the system passes ozone may quickly develop in the hot, humid air mass.

We have decided to err on the side of caution for Friday’s air quality forecast and we are continuing the Action Days for both southwest and southeastern parts of the state. Southwesterly winds will prevail under the continued hot, humid air mass. Storm development chances look less for tomorrow and further north. The air quality forecast will be dependent on storm development; however, even just a few hours of afternoon into early evening sunshine could allow for fast increases in ozone. So, Action Days already set in place will be continued.

Fine particulate could also see increases the next few days with readings ranging from upper Good to middle Moderate.

EXTENDED FORECAST:

Extended models show hot conditions lingering through Saturday. Air Quality Division (AQD) forecasters will be holding another call Friday morning to discuss possible Action Days for Saturday. A front passing late Saturday should end the threat for increased pollution early next week.

Next forecast update: Friday, July 19th, 2019
Update by: Stephanie M. Hengesbach, Meteorologist, Air Quality Division Michigan Department of Environment, Great Lakes, and Energy

07/17/2019 Forecast Update

FORECAST SUMMARY:

Wednesday, July 17th, 2019 through Thursday, July 18th, 2019

...AIR QUALITY ACTION DAY ADVISORY FOR THURSDAY JULY 18TH...

IN WEST MICHIGAN:

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

Ozone: 8-hour Ozone concentrations will range between Good and Moderate with USG possible in the west and southeast Thursday.

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

FORECAST DISCUSSION:

The heatwave that has been forecast a few days now is ready to begin. Wednesday the region is still experiencing increased moisture, scattered clouds and small chances for precipitation from the remnants of what was Hurricane Barry. This system finally pulls out of the area; however, upper level ridging builds in Thursday bringing very warm surface and upper level temperatures. Humidity levels will also be increasing with heat indexes approaching or exceeding 100 degrees in many locations. As for air quality, when and where storms may develop is making the forecast tricky.

For Wednesday, partly sunny skies and winds with a northeasterly component should keep ozone in the Good to Moderate range. On Thursday, a storm complex is expected to develop over northern Wisconsin and track east early in the day. Current models keep this complex from slipping into the southern half of Lower Michigan. This means, sunshine will be more prevalent in the south and that, coupled with warm surface and upper level temperatures, and southwesterly winds, make increased ozone a good possibility. The threat is high enough to warrant Action Days for Thursday in both the southwest and southeastern portions of the state.

The threat for increased ozone could linger into Friday, therefore, the regional forecasters will talk Thursday morning to determine if the Action Day should be continued.

Fine particulate could also see slow increases the next few days with readings ranging from upper Good to lower Moderate.

EXTENDED FORECAST:

Extended models show hot conditions lingering through most of the weekend. AQD forecasters will be keeping eye on conditions to determine if Action Days are needed over the weekend.

Next forecast update: Thursday, July 18th, 2019
Update by: Stephanie M. Hengesbach, Meteorologist, Air Quality Division Michigan Department of Environment, Great Lakes, and Energy

07/15/2019 Forecast Update

FORECAST SUMMARY: Monday,

July 15th, 2019 through Wednesday, July 17th, 2019

AN ACTION DAY ADVISORY REMAINS IN EFFECT FOR MONDAY, JULY 15th IN THE FOLLOWING MICHIGAN COUNTIES...

IN WEST MICHIGAN:

ALLEGAN...  KENT...  MUSKEGON...  AND OTTAWA COUNTIES

Ozone:  8-Hour average Ozone concentrations will be a mixture of Good and Moderate through Wednesday.  Several areas may experience USG levels on Monday

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

FORECAST DISCUSSION

As of noon, Monday’s forecast for elevated ozone in West Michigan and Southeast Michigan looks to be a good forecast.  Morning hourly concentrations have been steadily climbing and most of the skies in the southern half of the Lower Peninsula are clear.  There are possibilities of pop-up showers, later in the afternoon, but those will be hit or miss.

Tuesday and Wednesday do not appear to be much of a threat for Air Quality as the remnants of Tropical Storm Barry work its way into the Midwest bringing clouds and shower potential.

The three-day stretch of Thursday through Saturday looks to be problematic.  It promises to be true summer with high temperatures and humidity with little cloud relief.  With the sun as strong as it is during July and light winds, it is easy to imagine that we could see elevated ozone over those days.  As such, the forecasters are planning another discussion on Wednesday.

EXTENDED FORECAST:

There is a potential for poor Air Quality during the end of the week as hot, muggy weather settles in.

Forecast updated by Jim Haywood: Monday, July 15th, 2019
Next forecast update: Wednesday, July 17th, 2019

07/14/2019 Forecast Update

FORECAST SUMMARY:

Sunday, July 14th, 2019 through Monday, July 15th, 2019

AN ACTION DAY ADVISORY IS IN EFFECT FOR MONDAY, JULY 15th IN THE FOLLOWING MICHIGAN COUNTIES...

IN WEST MICHIGAN:

ALLEGAN...  KENT...  MUSKEGON...  AND OTTAWA COUNTIES

Ozone: 8-Hour average Ozone concentrations will be a mixture of Good and Moderate through Sunday. Several areas may experience USG levels on Monday

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

FORECAST DISCUSSION

Sunday looks to remain in theGood/Moderate category, throughout the state, with favorable winds and temperatures.

However, hopes of staying in the Good/Moderate category, during Monday, have been diminished with the latest model runs. All the weather models have surface winds shifting from southeast, in the morning hours, to the south/southwest during the afternoon. Temperatures are expected to reach near 90 with a muggy dew point around 70. Earlier model runs were indicating a decent cloud cover, Monday afternoon, which would have reduced ozone production. But the later runs are trending more for clearer skies although pop-up showers could occur.

Almost all the ozone models are showing significant ozone production in the Allegan, Ottawa, Kent, and Muskegon area, which would be consistent with the wind pattern. As such, an Action Day Advisory has been issued for those counties.

EXTENDED FORECAST:

There is potential for poor Air Quality during the next work week as hot, muggy weather settles in.

Forecast updated by Jim Haywood: Sunday, July 14th, 2019

Next forecast update: Monday, July 15th, 2019

07/12/2019 Forecast Update

FORECAST SUMMARY:

Friday, July 12th, 2019 through Sunday, July 14th, 2019

Ozone:  8-Hour average Ozone concentrations will be a mixture of Good and Moderate through Sunday.

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

FORECAST DISCUSSION

We will enter into the weekend with Air Quality on the Good side.  That trend will last through Saturday as a cold front drops down through the state.  There may be some convective activity associated with the frontal passage but the indicators are that this is more unlikely than likely.  Winds will shift to the northwest during the afternoon and provide a good cleanout of the atmosphere.

Post-frontal winds, during Sunday, will be light and biased to the northeast shifting to southeast.  The areas most at risk for any ozone creep will be west of the Detroit area, such as Flint.  But, coming off a clean Saturday, it is unlikely that the creep would be any worse than Moderate.

The upcoming work week may be challenging for Air Quality forecasting.  Indications are that we will be entering a prolonged period of hot, humid weather ripe for ozone production.  The wild card is Tropical Storm Barry, currently in the Gulf of Mexico, and not knowing how it will influence our upcoming weather.

Considering the uncertainty, the latest model runs will be reviewed on Sunday and this forecast will be updated.

EXTENDED FORECAST:

Air Quality is currently expected to remain mixed Good to Moderate going into the next work week.

Forecast updated by Jim Haywood: Friday, July 12th, 2019
Next forecast update: Sunday, July 14th, 2019

07/08/2019 Forecast Update

FORECAST SUMMARY:

Monday, July 8th, 2019 through Friday, July 12th, 2019

Ozone: 8-hour Ozone concentrations will range between Good and Moderate.

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

FORECAST DISCUSSION:

Pleasant July weather can be expected Monday and Tuesday with plenty of sunshine and seasonable temperatures. One notable feature will be the hazy sunshine due to smoke in the upper atmosphere associated with wildfires burning in Canada. A weather change comes into play Wednesday as a low-pressure area crossing the upper Great Lakes region brings a cold front through. High pressure then builds back in for the end of the week.

As for air quality, cooler upper level temperatures and southeasterly winds should keep ozone from increasing higher than Moderate Monday or Tuesday. Clouds increase Wednesday in most locations which should keep ozone Good to Moderate. However, with the later frontal passage in the southeast, more sunshine is expected. This coupled with southwesterly winds and warmer surface and upper levels temperatures may produce increased ozone in that portion of the state. Weather maps will be re-evaluated Tuesday and this forecast will be updated if ozone levels change. Northwesterly winds develop after the Wednesday frontal passage bringing back Good ozone readings.

Fine particulate will likely linger in the upper Good to Moderate range most of the week.

EXTENDED FORECAST:

Extended models show high pressure in place for the coming weekend and models also differ on chances for precipitation. Models do, however, agree that another warmup is in store. Regional forecasters will be talking Friday morning to discuss the potential for increased pollution levels later in the period.

Next forecast update: Friday, July 12th, 2019
Update by: Stephanie M. Hengesbach, Meteorologist, Air Quality Division, Michigan Department of Environment, Great Lakes, and Energy

07/03/2019 Forecast Update

FORECAST SUMMARY:

Wednesday, July 3rd, 2019 through Monday, July 8th, 2019

...AIR QUALITY ACTION DAY ADVISORY FOR WEDNESDAY JULY 3RD... IN SOUTHEAST MICHIGAN:LENAWEE... MACOMB... MONROE... OAKLAND... ST. CLAIR... WASHTENAW... AND WAYNE COUNTIES

Ozone: 8-hour Ozone concentrations will range between Good and Moderate, with scattered USG possible.

PM-2.5: 24-hour Fine Particulate concentrations will range from upper Good to middle Moderate; USG is possible during the evening and overnight in areas with fireworks displays.

FORECAST DISCUSSION:

The weather forecast through Friday hasn’t changed much with warm, muggy conditions continuing, along with the chance for scattered storms. Storm chances Wednesday are confined more to the southern portion of the state closer to a frontal boundary. The threat for storms does increase for the July 4th Holiday and for Friday.

Ozone levels the past few days has increased in some locations, generally the southeastern and southwestern portions of the state. This trend could continue in areas that have more in the way of sunshine. With winds remaining lighter, the best chance for increased ozone Wednesday would be in the southeast and we have an Action Day in place to cover this threat. Storm chances increase Thursday and Friday. Conditions will be warm and southwesterly winds develop. A few locations may reach low-end USG if sunshine prevails; however, storms and associated clouds should stop levels from increasing higher than Moderate Thursday or Friday. An airmass change begins late Friday/Saturday with northeast winds developing as high pressure slides in from the northwest. This will improve ozone levels for Saturday.

As for fine particulate, levels have been ranging from Good to Moderate and this trend will continue. The caveat to this is areas near fireworks displays in celebration of the July 4th Holiday. Fine particulate will quickly increase into the USG range in those localized areas which could linger into the overnight hours.

EXTENDED FORECAST:

Extended models show high pressure in place early next week bringing pleasant conditions Sunday, into Monday. With plenty of sunshine and seasonable temperatures, Moderate ozone may develop; however, levels higher than that are not expected. Fine particulate should be Good early next week.

Next forecast update: Monday, July 8th, 2019
Updated by: Stephanie M. Hengesbach, Meteorologist, Air Quality Division, Michigan Department of Environment, Great Lakes, and Energy, 517-284-6746 | hengesbachs1@michigan.gov