Forecast Discussion

Fine particulate levels have elevated into the low Code Yellow range across the interior while remaining in the Code Green range elsewhere.

Remnant Canadian high pressure remains anchored overhead, slowly stagnating the very clean, dry air mass it deposited earlier in the week. Additionally, some increase in residential wood burning and some localized prescribed burning activity (see in satellite fire detects and reports) are all adding to the net fine particulate levels across the air shed.

As the high pressure continues to linger through the period, the air mass will slowly continue to stagnate. Expect hourly fine particulate levels to rise overnight in response to reduced vertical mixing and horizontal dispersion due to a relatively strong near-surface temperature inversion, before slowly decreasing during the daytime as dispersion increases. As a result, net fine particulate daily averages will likely continue to slowly edge upward through the forecast period.

On Monday, another strong blast of very dry, Canadian air will clean out the air shed and fine particulate levels should lower back into the Code Green range statewide.