Gusty north to east winds through Thursday, strongest tonight into Wednesday morning. Widespread valley highs around 90 this weekend.
Discussion
Satellite imagery shows another strong short-wave trough sliding southeastward in northwesterly flow across northeast California bringing a batch of high clouds to the region. Otherwise, skies are clear other than some lingering clouds over the far northern Sierra and southern Cascades. Northerly surface pressure gradient has begun to tighten (MFR-RDD up to about 5 mbs), but onshore flow continues further south. Local northerly gusts of 15-30 mph have already spread into the northern Sacramento Valley and surrounding terrain.
Offshore wind pattern sets up for the next several days as NorCal will be in between ridging building to our north over the PacNW and a weak trough hanging back across southern Nevada into central California. Northerly breezes will spread down the Central Valley today as the remaining onshore gradient slackens. Stronger northerly gusts are expected tonight into early Thursday as offshore gradients tighten with pressure rises over the Great Basin. Gusts of 35-45 mph will be likely across much of the Sacramento Valley to the northwest of Sacramento where a Wind Advisory has been posted.
There’s also potential for strong winds on the west slopes of the northern Sierra Wednesday night into Thursday morning as easterly surface gradient tightens beneath strengthening northeast to east flow aloft. EC EFI continues to show a signal for anomaly during this period, and if this trend continues an extension of the Wind Advisory may be warranted.
Otherwise, the warming and drying trend will continue this week as valley temperatures work their way up from the 70s today, to the upper 70s and 80s on Wednesday, and into the mid and upper 80s on Thursday. By Friday it’s looking more likely that we’ll see our first day this season of widespread highs in the lower 90s across the Central Valley (NBM probabilities are above 80 percent).
Extended Discussion (Saturday through Tuesday)
EPAC upper ridge remains main synoptic feature through the extended forecast period. As a result, dry weather expected with above normal temperatures. High temperatures in the Central Valley forecast in lower to mid 90s, about 15 degrees above normal, with mainly 70s and 80s for the mountains and foothills.