A storm from the North Pacific will push into the central San Joaquin Valley Tuesday morning, bringing a band of rain and setting up scattered thunderstorms later in the day. The strongest activity is expected in Fresno, Madera, Merced and Mariposa counties Tuesday afternoon and evening, and some of those storms could turn strong.
The change will be sharp after a warm weekend. Highs reached 81 in Merced and Hanford, 82 in Fresno, Visalia and Madera, and 83 in Porterville on Saturday, and Sunday is expected to push into the middle 80s in the Valley before temperatures fall back into the low 80s on Monday with a few high clouds. By Tuesday, highs should drop into the upper 60s.
The storm also reaches the Sierra Nevada with a winter feel that has been absent for much of the month. Snow levels should hover around 6500 feet during the day Tuesday, then fall to near 5000 feet Tuesday night. At Shaver Lake, rain is expected to change over to light snow Tuesday night. A Winter Storm Watch is in effect for the entire Sierra Nevada from late Monday night through Wednesday afternoon.
The mountain forecast calls for 3 inches to 5 inches of new snow from 7000 feet to around 8000 feet, with the higher peaks likely to pick up another 12 inches to 18 inches. That means the same system that brings wet roads and thunderstorms to the Valley will leave some mountain travel dealing with much tougher conditions overnight and into Wednesday.
For Fresno and the surrounding counties, the key question is not whether the weather changes, but how fast. The answer is Tuesday: rain first, thunderstorms by afternoon, and a much cooler day than the Valley has seen in recent days.
