12/17/2021 Forecast Update
FORECAST SUMMARY:
FORECAST SUMMARY: Friday, December 17th, 2021 through Monday, December 20th, 2021
PM-2.5: 24-hour average Fine Particulate levels will be generally good, with only scattered low Moderates through the forecast period.
FORECAST DISCUSSION:
After another windy storm system this week, conditions turn quieter for the end of the week and weekend. A storm system tracking across the Ohio River Valley Friday/Saturday will come close enough to bring chances for snow, but significant accumulations are not anticipated. As the system tracks east, high pressure settles in from the west/northwest and winds veering to the north/northwest could bring scattered lake effect snow Saturday. Sunday should be partly to mostly sunny but cool across the state with high-pressure overhead. The next weather system tracks a low north of Lake Superior Monday with a weak cold front passing through.
An unexpected uptick in hourly fine particulate levels was seen Thursday. Upon further evaluation, it was found this was likely due to smoke from Oklahoma wildfires being transported by the strong southwest winds. The plume was seen on satellite imagery and the plume was picked up by most monitors as it mixed to the ground. Increases in hourly concentrations did not last long in any area and the daily averages of fine particulate were not higher than low Moderate at any location.
As for the forecast, low fine particulate readings Friday will not increase much during the day and Good daily averages are expected. Winds turn easterly later Friday as the storm system tracks closer to the state and the flow then turns northerly Saturday after it passes east. Fine particulate will remain Good Saturday. Weaker winds may allow for a few increased hourly fine particulate concentrations, especially in the southeast, on Sunday; however, daily averages of fine particulate will not be higher than low Moderate.
EXTENDED FORECAST:
Extended forecast models show a weak cold front passing through early next week. Weaker southerly winds ahead of the boundary could allow for some low Moderate fine particulate Monday.
Forecast updated by Stephanie Hengesbach: Friday, December 17th, 2021.