2/23/2024 Forecast Update

FORECAST SUMMARY: Friday, February 23, 2024, through monday, February 26, 2024

PM-2.5: 24-hour daily average Fine Particulate concentrations are expected to range between Good and low Moderate through the forecast period.

FORECAST DISCUSSION: Fine particulate levels on Thursday were running high across the southern half of lower Michigan thanks to an inversion that lingered through the day, causing pollution to increase at ground level. Hourly fine particulate readings reached the USG range for a portion of the day; however, only one monitor ended up reaching low-end USG for the daily average; most other sites ended the day in the middle to upper Moderate range. Pollution levels are improving today, Friday, thanks to a frontal boundary dropping in. This front will bring in cooler temperatures for the end of the week, along with small chances for snow showers. This cooldown will be short-lived, as a warmup is already anticipated for Sunday.

Hourly readings of fine particulate Friday morning range from Good further north to Moderate in southern locations. As the front passes during the day, winds pick up from the northeast, which will bring hourly concentrations back into the Good range statewide. Daily averages of fine particulate are expected to be mostly Good Friday, aside from a possible low-Moderate lingering in the southeast.

Cooler temperatures move over the state Friday and Saturday as surface high pressure moves in behind the cold front. Temperatures will fall during the day on Friday, and highs on Saturday will be below normal for this time of year. Weaker winds will be in place Saturday as the high slides overhead, but fine particulate should remain mostly Good for the day. Stronger southerly winds develop on Sunday, rebounding temperatures from the cool Saturday. Wind speeds should be strong enough to keep the atmosphere well-mixed, allowing for a continuation of mostly Good fine particulate levels.

EXTENDED FORECAST: Extended forecast models show a weak system passing northeast of the state late Sunday, decreasing wind speeds for a time early Monday. Stronger southwest winds move in quickly behind it, and a warmup is still in the forecast for early to mid-week. Without a stagnant period anticipated in the long term, pollution levels into next week should remain in the Good to low Moderate range.

Next Forecast Update: Monday, February 26th, 2024

2/20/2024 Forecast Update

FORECAST SUMMARY: Tuesday, February 20, 2024, through Friday, February 23rd, 2024

PM-2.5: 24-hour daily average Fine Particulate concentrations are expected to range mostly Moderate through the forecast period.

FORECAST DISCUSSION: Mild conditions persist through mid-week, with generally sunny skies on Tuesday turning a bit cloudier on Wednesday and Thursday. A weak system over the region may produce some light precipitation on Wednesday, but most areas remain dry. On Thursday, a storm system tracks from west to east through the Ohio River Valley. Precipitation from the system may reach portions of the state, but a more noticeable change in conditions comes Friday as an arctic cold front drops in from the north, bringing colder temperatures and lake-effect snow back into the forecast.

Fine particulate levels Tuesday morning have been running from middle to upper Moderate across the central and southern portions of the state. Hourly concentrations should improve as the day progresses; however, daily averages in the Moderate range are expected across most of the lower peninsula. On Wednesday, southerly winds pick up and warmer air moving in will help dissipate some of the snowpack that still exists. The increase in moisture will keep daily averages of fine particulate mostly Moderate statewide, and like Tuesday morning, a few morning hourly readings may be in the high Moderate to low-end USG range before falling to middle Moderate late morning. Moderate concentrations may linger into Thursday as well, but the cold front dropping in from the northwest on Friday will improve any buildup and bring back Good pollution levels for the end of the week.

EXTENDED FORECAST: Extended forecast models show the cooldown being short-lived, with another warm-up for next week. Weekend fine particulate levels should remain mostly Good but could increase towards Moderate again if the warmup pans out.

Next Forecast Update: Friday, February 23rd, 2024

2/16/2024 Forecast Update

FORECAST SUMMARY: Friday, February 16, 2024, through Tuesday, February 20th, 2024

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

FORECAST DISCUSSION: A return to winter was felt in the latter half of this week with essentially all of Michigan receiving some form of wintry precipitation. Along with a return of snow, temperatures dropped to near-normal temperatures and will be below normal as we start off our weekend on Saturday with highs ranging in the 20s. NNE winds will be dominating the region this weekend and is the culprit for the below-normal temperatures. Due to the cooler temperatures and NNE winds, lake-effect snow will be present throughout the weekend, especially for communities along Lake Superior and in the northwestern Lower Peninsula. Although winds stay relatively the same directionally, upper-level patterns bring slightly warmer air back to Michigan on Sunday with temperatures in the low-mid 30s. A reversal of the winds occurs on Monday as a pressure system moves into the region from out west, which will bring warmer southwesterly winds. This will continue into early next week as yet another warmup is on the horizon.

For air quality, due to the predominantly northerly winds for the majority of the weekend, PM-2.5 concentrations will not be an issue as cleaner air will be regularly blown into the region. Conditions will also be breezy at times so the odds of long-lasting inversions are low. In the latter half of the weekend and going into next week, warmer temperatures and change in air direction will allow for some particulates to increase, hence why I have a Good to low-Moderate range for the PM-2.5 forecast.

EXTENDED FORECAST: As stated above, a warmup is on the horizon for the middle of next week with the 50s returning to the area. Increases in surface temperatures and a disjointed snowpack across the state may allow for PM-2.5 concentrations to approach the mid-to-high Moderate range.

Next Forecast Update: Monday, February 20th, 2024

2/13/2024 Forecast Update

FORECAST SUMMARY: Tuesday, February 13, 2024, through friday, February 16, 2024

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

FORECAST DISCUSSION: Seasonal normal temperatures have returned to the Great Lakes with upper-20 to mid-30s expected throughout this week. Although temperatures have decreased from last week’s record high temperatures, the sun will be more present this week than it was for the majority of January. Today, Tuesday, and Wednesday will have High-pressure in place which will provide ample sunlight. These High-pressure systems remain in place until Thursday morning when a Low-pressure system treks through the region from the southwest. Accompanying the Low-pressure will be an associated cold front and moisture from the south which will aid in producing snowfall for much of Michigan. North of the I-69 corridor will have the highest snowfall amounts with expected snowfall accumulation in the three-to-five-inch range with some higher accumulations locally. This system will be rather quick-moving, so snowfall will mainly take place during the day on Thursday and the entire system will be over the east coast by Friday morning. Friday will have leftover snowfall with less accumulation for the interior areas, and lake-effect snow for shoreline communities.

For PM-2.5, with the current High-pressure regime, expect Moderate PM-2.5 concentrations in the morning hours when winds are light and atmospheric inversions are possible. The atmospheric inversions should dissipate throughout the day, allowing for the dispersion of pollutants being trapped near the surface. During these inversions, and morning commutes, it is possible for PM-2.5 concentrations to eclipse the Unhealthy for Sensitive Groups threshold for an hour or two. Moderate is forecasted, however, due to the expected 24-hour average being in the Good to Moderate range. Due to the system coming through on Thursday, any buildup of concentrations will be cleaned out, moving us back into a consistent Good-range regime.

EXTENDED FORECAST: Cooler temperatures are expected this weekend with surface highs in the 20s. Northerly winds will help in providing us Good air quality into the next week.

Next Forecast Update: Friday January 16th, 2024

2/9/2024 Forecast Update

FORECAST SUMMARY: Friday, February 9, 2024, through Tuesday, February 13, 2024

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

FORECAST DISCUSSION: After a night where thunder was heard in many areas, Friday will be the last day of near record high temperatures for this time of year.  We are expecting clear skies with downstate temperatures in the mid-50’s.  Much of this can be contributed to being in the warm air advection sector of an advancing frontal system. 

While we have seen mostly Moderate conditions during the week, it will be cleaned out Friday with increasing winds, shifting winds and cooling temperatures in time for the weekend.  As the winds become more northwesterly during Saturday, daily high temperatures will drop into the 30’s and low 40’s, which is still a bit above normal for this time of year.

Air Quality will remain Good through the weekend and the beginning of the next work week.  Due to scheduling, the next scheduled forecast call and update will be Tuesday.

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

Next Forecast Update: Tuesday, February 13, 2024

2/5/2024 Forecast Update

FORECAST SUMMARY: Monday, February 5th, 2024, through Friday, February 9th, 2024

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

FORECAST DISCUSSION: High pressure continues to dominate the region bringing much appreciated clear skies and sunshine to the state.  In addition, we are looking at a gradual warmup during the week with potentially record high temperatures near 60 by Thursday. 

The warming temperatures, calm winds and ample moisture also bring the possibility of increasing fine particulates.  Clear skies at night have the tendency to create an inversion trapping air near the ground.  With the morning rush hour occurring at the same time, we usually see a spike in morning particulate concentrations in the more urban areas.  During the summer, the strong daytime sun will break up that inversion allowing vertical dispersion and dilution of surface pollutants.  However, with the weaker winter sun, the inversion stands a better chance of staying intact during the day keeping those pollutants trapped near the surface.

We saw that Sunday with higher PM-2.5 values in the 20-30 ug/m3 range, especially in Southeast Detroit.  That trend will likely continue through the week with the warming temperatures and the forecast models are also indicating that trend.

As such, I will be forecasting increasing Moderate through much of the state with particulates accumulating due to no change in air mass.  While I currently have no strong reason to think it will be any worse than Moderate, I will be keeping an eye on our monitors and will update this forecast if any areas look to trend into the USG range.  Otherwise, this forecast will be updated on Friday for the normal weekend forecast.

EXTENDED FORECAST: Air Quality should be generally Moderate trending back to Good beginning the weekend.

Next Forecast Update: Friday, February 9th, 2024

2/2/2024 Forecast Update

FORECAST SUMMARY: Friday, February 2nd, 2024, through Monday February 5th, 2024

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

FORECAST DISCUSSION: One month down already in 2024 as February starts off with Spring-like temperatures and relatively sunny conditions. After a week of somewhat cloudy and foggy conditions, a High-pressure system lingers in the Great Lakes region for the length of the weekend ahead which will provide clear conditions. Surface temperatures throughout the weekend will range from the low-40s to mid-40s, but with the sun shining, it may feel a tad warmer. Wind direction will be shifting all weekend due to the High-pressure system moving around the Great Lakes. Although winds on Sunday will be northerly, surface temperatures will still be in the 40s due to upper-level patterns bringing warmer air to the area. These northerly winds will carry into Monday with the start of next week looking almost identical to Sunday in terms of sunshine and warmer surface temperatures.

In terms of air quality, PM-2.5 will start off in the Good range and slowly approach the low-Moderate range as the weekend comes to a close. With the High-pressure in place, winds will be light and will allow for particulates to hang around longer before dispersing. The morning hours, especially, will see more Moderate concentrations in the more populated areas, but winds, although light, will pick up throughout the day and help to clean out the airmass.

EXTENDED FORECAST:

The warm temperatures this weekend carry into the next week with some areas in the 50s towards the latter half of the week. High-pressure slowly moves off to the east, so winds will continue to be light which will allow for some Moderate PM-2.5 concentrations. Overall air quality will range from Good to Moderate into the next week.

Next Forecast Update: Monday, February 5th, 2024

1/29/2024 Forecast Update

FORECAST SUMMARY: Monday, January 29, 2024, through Friday, February 2, 2024

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

FORECAST DISCUSSION:
This week starts with cloudy skies and moderate wintertime temperatures. There are not any large storms on the horizon, but a few systems will bring chances for precipitation. The first system tracks from the western upper peninsula late Monday to the southeastern portion of the state late Tuesday. Precipitation falls predominantly as snow further north and east, while a mix of rain and snow may be seen in western and central areas. High pressure then builds in for midweek before another clipper system passes through late Thursday into Friday. Not much precipitation is associated with this disturbance, so many locations will remain dry, but cooler air does filter in in its wake.

Fine particulate levels start the week in the Good range. The two systems moving through Tuesday and then Thursday prevent any prolonged periods of stagnation, therefore not allowing pollution to significantly build. While there may be periods, especially in the morning hours, where hourly concentrations of PM2.5 reach the Moderate range, daily averages are expected to remain mostly Good with only a few low-Moderates possible through the forecast period.

EXTENDED FORECAST:

Extended forecast models show high pressure positioned northeast of the state by this coming weekend. This will set the stage for dry conditions, and finally, a few days with sunshine are expected. Pollution levels in the long term should remain mostly in the Good to low-Moderate range

Next Forecast Update: Friday, February 2, 2024

1/26/2024 Forecast Update

FORECAST SUMMARY: Friday, January 26th, 2024, through Monday, January 29th, 2024

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

FORECAST DISCUSSION:
We end this week warmer than we started with the majority of Michigan in the 30s today, Friday. This trend continues into the weekend with surface highs ranging from the low to upper 30s. Upper-level wise, this weekend will be rather active with a high-pressure system traversing the Great Lakes all weekend, which will shift the wind direction each day through Monday. Although we will be under high-pressure, Michigan will be mostly cloudy throughout the weekend with morning fog throughout the state due to warmer surface temperatures and a melting snowpack. Sunday into Monday may see a quick passing system that will bring a wintry mix of snow and rain with little to no accumulation.

In terms of air quality, due to the melting snowpack throughout the state, PM-2.5 concentrations may reach mid-to-high Moderate levels during hours throughout the weekend, but shifting winds and passing fronts will help keep the overall air quality Good. Each morning will likely have an atmospheric inversion, so expect Moderate levels for a few hours in more populated areas due to the trapping of particulates near the surface and light winds.

EXTENDED FORECAST:

The start of next week looks somewhat similar to the end of this week with passing fronts and cloudy skies. However, warmer temperatures are on the horizon with surface temperatures expected to reach the 40s in some areas. Overall air quality is expected to remain Good.

Next Forecast Update: Monday, January 29th, 2024

1/19/2024 Forecast Update

FORECAST SUMMARY: friday, January 19, 2024, through monday, January 22, 2024

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

FORECAST DISCUSSION:
Cold weather continues across the region, but relief is in sight for next week.  Currently, a light snow is falling Friday morning, thanks to an upper atmosphere short wave of pressure.  Lake effect snow will continue along the western lakeshore counties.

In terms of  Air Quality, it has been mostly Good thoughout the week and should continue through the weekend.

I expect the current snow showers and colder temperatures to continue through Saturday.  By Sunday, we may actually see some sun and slightly warmer temperatures.  We could come close to the freezing mark by Monday, which carries the risk of some freezing rain.  We finally go north of the freezing mark on Tuesday with temperatures reaching the upper 30’s. 

With the warm-up over a good snowpack, we may see fine particulates creep into the Low Moderates, next week, but I will leave that for the Monday forecast.

EXTENDED FORECAST:

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

Next Forecast Update: Monday, January 22, 2024

1/16/2024 Forecast Update

FORECAST SUMMARY: monday, January 16, 2024, through friday, January 19, 2024

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

FORECAST DISCUSSION:
Bitter cold across a large portion of the continental U.S. remains the “hot” topic in the world of weather.  Fortunately, we are not looking for any major storms to hit our area in the near forecast.  The west side of the state probably will not know the difference as lake effect snow shows look to continue through Saturday the weekend. 

In terms of Air Quality, current readings are in the Good range and should remain that way for the next few days.  The only exception may be in urban areas, around the Thursday time frame, when calm winds prevail and some localized stagnation may set in.  In that case, we may see some Low Moderates but nothing worse.

So, when does this bitter cold weather end?  The current models have us breaking out late in the weekend.  By Sunday, we should be edging back to “normal” January temperatures and rise above the freezing mark on Monday to begin a slight thaw and some melting.

EXTENDED FORECAST:

Air Quality should be generally Good to Low Moderate entering the weekend.

Next Forecast Update: Friday, January 19, 2024

1/16/2024 Forecast Update

FORECAST SUMMARY: monday, January 16, 2024, through friday, January 19, 2024

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

FORECAST DISCUSSION:
Bitter cold across a large portion of the continental U.S. remains the “hot” topic in the world of weather.  Fortunately, we are not looking for any major storms to hit our area in the near forecast.  The west side of the state probably will not know the difference as lake effect snow shows look to continue through Saturday the weekend. 

In terms of Air Quality, current readings are in the Good range and should remain that way for the next few days.  The only exception may be in urban areas, around the Thursday time frame, when calm winds prevail and some localized stagnation may set in.  In that case, we may see some Low Moderates but nothing worse.

So, when does this bitter cold weather end?  The current models have us breaking out late in the weekend.  By Sunday, we should be edging back to “normal” January temperatures and rise above the freezing mark on Monday to begin a slight thaw and some melting.

EXTENDED FORECAST:

Air Quality should be generally Good to Low Moderate entering the weekend.

Next Forecast Update: Friday, January 19, 2024

1/8/2024 Forecast Update

FORECAST SUMMARY: Monday, January 8, 2024, through Friday, January 12, 2024

PM-2.5:  24-hour daily average Fine Particulate concentrations are expected to range mostly Good through the forecast period.

FORECAST DISCUSSION:
Weather conditions Monday will be relatively calm with cloudy skies and reasonable temperatures; however, a change is quickly approaching with two winter storms expected this week. The first spreads snow from southwest to northeast, starting late Monday into early Tuesday. The highest snow accumulation with this storm is expected further north, while less accumulation is expected further south due to warmer air wrapping in, changing snow to rain. A weak system keeps mainly snow in the forecast late Wednesday into Thursday, but a second stronger storm moves in from the southwest late Thursday into Friday. The current track of this storm keeps us on the cool side of the system, with accumulating snow a good possibility late in the week.

Hourly fine particulate readings Monday morning have been Moderate due to weaker winds and increased surface moisture. As the storm system approaches, wind speeds are forecast to increase from the south/southeast late Monday, which should improve hourly readings; however, daily averages of fine particulate Mondays will likely range from low to middle Moderate. Improvements in fine particulate can be expected Tuesday due to stronger, gusty winds changing to the northeast, then northwest as the storm pulls away. A weak system moves late Wednesday, continuing the active weather pattern and hampering any significant increase in pollution levels. While a few hourly concentrations of fine particulate matter in the low-Moderate range may be seen Wednesday or Thursday, daily averages should remain in the Good range. Strong east/southeast winds develop Friday ahead of the late-week storm. Fine particulate levels at that time should remain mostly Good.

EXTENDED FORECAST:

Extended models show artic air moving in on a strong northwest flow this coming weekend. The expected conditions would keep snow in the forecast, and air quality would average Good across the state.

Next Forecast Update: Friday, January 12, 2024

1/5/2024 Forecast Update

FORECAST SUMMARY: Friday, January 5th, 2024, through Monday, January 8th, 2024

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

FORECAST DISCUSSION:

After a sunny Thursday we are met with yet another cloudy January day on this Friday. Surface temperatures will be near normal for the majority of the state with relatively light WSW winds. These light winds will increase throughout the weekend as a busy weekend, weather-wise, is in store for the Great Lakes. A Low-pressure system is expected to traverse the area to our north on Saturday and into Sunday, which will bring flurries to the lower peninsula and a couple of inches of snow to the upper peninsula. A cold front is associated with the Low-pressure but surface temperatures will remain near normal temperatures with highs in the upper-20s through mid-30s. Monday is a relatively quiet day with the Low-pressure exiting the area, but the cold front may hang around throughout the day.

For air quality, with the change in airmass expected to last all weekend, PM-2.5 concentrations are expected to be in the Good to low-Moderate range. Early morning light winds will allow for PM-2.5 concentrations to build up, but persistent winds will help clear out any daily buildup that accrues.

EXTENDED FORECAST:

The beginning of next week may present all of Michigan with a decent chance of accumulating snow. There is a strong Low-pressure system expected to make its way into the Midwest, but the exact track of the system has yet to be fine-tuned and there is still wiggle room between snow and rain showers for the majority of the state.

Next Forecast Update: Monday, January 8th, 2024

1/2/2024 Forecast Update

FORECAST SUMMARY: Tuesday, january 2nd, 2024, through friday, January 5th, 2024

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

FORECAST DISCUSSION: 2024 is here and the New Year provides us with seasonably normal surface temperatures this week with a chance of precipitation for much of the state. A Low-pressure system hangs out just to our north over Lake Superior the beginning of this week and slowly moves south on Wednesday going into Thursday. It is when this Low-pressure and cold front move south that parts of Michigan may see some precipitation—mainly along the lake-effect snowbelts. Little accumulation is expected, however. If sunshine is what was wished for in the new year, the unfortunate news is that January is statistically the cloudiest month for Michigan. Although, after the Low-pressure moves out early Thursday, a High-pressure system quickly moves through and will provide us with some sunshine during the day. But as quickly as it appears, it will disappear, returning cloudy for the latter half of the week and into the weekend.

For PM-2.5 concentrations, Good to Moderate conditions are expected with light winds in place during the morning hours. The changes in airmass this week will help keep fresh air in the region and restrict any buildup in high concentrations. 

EXTENDED FORECAST: Cloudiness returns for the weekend after some sun on Thursday, but overall air quality will be Good.

Next Forecast Update: Friday, January 5th, 2024

12/28/2023 Forecast Update

FORECAST SUMMARY: Thursday, December 28, 2023, through Tuesday, January 2, 2024

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

FORECAST DISCUSSION:
This forecast constitutes my last forecast for 2023.  As I type 2024 for this first time, I look back on the 2023 Air Quality year-in-review.  I know that this year will be one that we will all remember for a very long time.  The widespread Canadian wildfires during June gave us PM-2.5 concentrations never seen in the history of Michigan air pollution forecasting and monitoring.  Concentrations of wildfire smoke pushed our AQI into the Unhealthy range and persisted for days.  We issued state-wide Air Quality Advisories for the first time in our program’s history.  Also, for the first time, we issued dual advisories for both ozone and fine particulates. 

Even though I believe we met the crisis head-on and addressed all news media requests, after the smoke departed, we met internally with our media department and outreach groups to discuss how we can better reach and inform the public if similar dangerous events should occur again.  

Fortunately, the remainder of 2023 saw an average number of elevated ozone days with no additional wildfire spikes after the June episodes. 

A potentially historically strong El Niño is currently giving us above normal temperatures and drier conditions for winter.  This is predicted to persist through the northern hemisphere throughout the winter.  We will see if that holds true…

As we enter the New Year’s weekend, our current Air Quality is Good as temperatures continue above normal.  Rain showers will eventually end on Friday and give us a drier day during Saturday.  Precipitation chances ramp back up during Saturday night.  Temperature forecasts indicate a rain/snow mix should be the worst although overnight temperatures could dip below freezing causing some slippery road conditions at night.  Air Quality is expected to remain mostly Good with a few isolated Low Moderates throughout the weekend.

Be careful and Happy New Year from your EGLE forecasters!

EXTENDED FORECAST: Air Quality should be generally Good to Low Moderate following the holiday weekend.

Next Forecast Update: Tuesday, January 2, 2024

12/26/2023 Forecast Update

FORECAST SUMMARY: Tuesday, December 26, 2023, through Thursday, December 28, 2023

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

FORECAST DISCUSSION:

Above normal temperatures will persist through Tuesday as we stay in the warm air sector of an approaching occluded front.  Tuesday’s temperatures should reach the upper 40’s to mid-50’s.  Some areas may even get close to record temperatures.

 For those traveling, I am expecting quiet weather with drier air and winds shifting to the north.  Daytime highs should still exceed 40 degrees keeping roads passable and too warm for any lake effect snow.

 Air Quality should remain mostly Good under northerly winds for the remainder of the work week.  For the New Year’s holiday weekend, I am expecting a brief shift back to southwest winds during Saturday with weekend temperatures well above freezing.

 I am not anticipating any Air Quality issues through the upcoming holiday weekend but will update the long weekend forecast on Thursday.

EXTENDED FORECAST: Air Quality should be generally Good to Low Moderate entering the holiday weekend.

Next Forecast Update: Thursday, December 28, 2023

12/21/2023 Forecast Update

FORECAST SUMMARY: Thursday, December 21, 2023, through Tuesday, December 26, 2023

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

FORECAST DISCUSSION:

Unseasonably warm weather is still forecast as we approach the Christmas holiday, with temperatures around 40 degrees on Thursday increasing into the 50s in southern locations early next week. Chances for precipitation exist during this forecast period. The first arrives later, Friday into Saturday, as a disturbance lifts a warm front north through the state. The southerly flow developing at that time brings in both increased moisture and precipitation. A short break in precipitation is expected Sunday, but the next system enters the region, bringing rain back into the forecast on Christmas day.

Fine particulate readings in the past few days have been mostly Good, but on Wednesday, some locations in the south reached into the low Moderate range. For this forecast period, I anticipate a mix of Good to Moderate fine particulate levels. Warmer temperatures and southerly winds may allow for increases; however, the systems moving through will hamper any long-term stagnation where pollutants will significantly develop.

EXTENDED FORECAST: Extended models show chances for precipitation lingering into mid-week next week, but a cooling trend is expected as well. Pollution levels in the extended forecast should continue in the Good to Moderate range.

Next Forecast Update: Tuesday, December 26, 2023

12/18/2023 Forecast Update

FORECAST SUMMARY: Monday, December 18, 2023, through Thursday, December 21, 2023

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

FORECAST DISCUSSION:

A winter weather set-up starts the new week, but it looks to be a week too early to give most of us a white Christmas. On Monday, strong northwest winds behind a departing cold front are producing lake-effect snows, with the highest accumulations expected in the northwest flow-prone areas. As the week progresses, northwesterly winds continue Tuesday but turn southwesterly Wednesday as high pressure slides in from the west. Temperatures at that time begin a warming trend, and dry conditions can be expected through mid-week as high pressure remains in control.

Fine particulate levels in the Good range will prevail Monday into Tuesday. As southerly winds develop and warmer temperatures move in, Moderate concentrations may come into play, especially as any snow accumulations from earlier in the week begin to melt, leading to increased surface moisture. Past Tuesday, a mix of upper-Good to middle-Moderate levels of fine particulate are anticipated through Thursday.

EXTENDED FORECAST: Extended models show small chances for precipitation towards the end of the week; however, conditions will be warm enough for rain. Above normal conditions continue in the long-term forecast. Pollution levels are expected to be range between Good and Moderate.

Next Forecast Update: Friday, December 21, 2023

12/15/2023 Forecast Update

FORECAST SUMMARY: Friday December 15th, 2023, through Monday December 18th, 2023

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

FORECAST DISCUSSION: Today, Friday, will see almost spring-like temperatures with highs nearing the 50s for most of the state. The majority of the lower peninsula has these temperatures coupled with clear skies, with the upper peninsula, however, seeing periodic rain for today and much of the weekend. This rain hangs around the region the entire weekend and slowly makes its way southward through Saturday and Sunday. A Low-pressure system lingering in the Midwest is the culprit for the weekend-long rain and cloudy conditions. As the Low-pressure moves off to the east on Sunday, a cold front drifts down from the north, which will drop temperatures back into the normal range of the low-30s. During the transition period of warmer temperatures to cooler, any precipitation that is still falling may turn into a wintry mix, but no real accumulation is expected. The combination of the aforementioned Low-pressure system moving to the east, and two High-pressure systems to the northwest and southwest will cause windy conditions on Monday for much of the Midwest, especially here in Michigan. As differing pressure systems move closer together (i.e., Low-pressure system and High-pressure system), the pressure gradient between the two becomes tighter. When the pressure gradient becomes tighter, this is what causes wind to pick up as wind goes from higher pressure to lower pressure. The pressure gradient being “squeezed” will only last for a day as Tuesday presents us with a change in airmass and pressure systems.

PM-2.5 concentrations currently are in the Moderate range as we have relatively stagnant conditions throughout the state. These concentrations may last through the day and into tomorrow until the wind picks up into the weekend. The more populated areas like Detroit and Grand Rapids will see higher Moderate concentrations compared to other areas in the state today and into tomorrow before the wind picks back up. There is currently no driver of dispersion, so the particulate matter is hanging around near the surface. As we get later into tomorrow, however, we will see plenty of airmass changes, rain, and wind so PM-2.5 will predominantly be in the Good category but expect hourly concentrations in the Moderate range in the aforementioned populated areas.

EXTENDED FORECAST:

After the breezy Monday conditions, temperatures start to rise again on Tuesday with overall Good air quality.

Next Forecast Update: Monday, December 18, 2023