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