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