Temperatures last week were well above average, with high temps for Fresno and much of the Central Valley reaching into the triple digits Wednesday and Thursday.
Now, as cooler temps in the 80s rush in out of the north with a persistent autumnal breeze, you may begin to truly feel like fall is in the air — even if there are still some days that reach 90 degrees in the forecast.
Cooler temps arrive this week
Winds out of the north will be a consistent feature today across the entire Central Valley. From Redding to Bakersfield, this breeze will be capable of gusting up to 30 mph mid-Monday, bringing cooler temps and drier air.
But this breeze is not the only thing diving in from the Pacific Northwest. In the upper atmosphere, a cut-off low is developing that will cool down temperatures substantially by Wednesday and Thursday.
A cut-off low is a region where the jet stream — the current of fast moving air at about the level where plans fly that divides the warm air to the south from the cold air to the north — pinches off in an eddy and begins to flow around itself. This vortex comes with lower air pressure and atmospheric heights around its center, cooling down temperatures nearly evenly and producing extra cloud cover in its wake…