Fire weather watch in the lower elevations, gusty north winds possible overnight

October 29, 2018 – Breezy north winds this week with elevated fire weather concerns. Cooler today, then warming and dry for the remainder of the week.

Discussion

Upper trough passing through the PacNW currently. Satellite imagery indicates a large area of high clouds off the coast beginning to spread across NorCal. Current temperatures are mostly cooler compared to 24 hours ago, but north winds across the northern Sacramento Valley have resulted in local warming there. Readings range from the upper 30s in the mountain valleys to the upper 40s to upper 50s across the Central Valley.

The upper level trough will dig southeastward early this week. This will bring a tightening north surface pressure gradient and will result in breezy northerly winds.

The highest winds gusts are expected along the western edge of the Sacramento Valley and coastal foothills late tonight and Tuesday. Gusts up to 35 mph will be possible. Northeasterly down slope winds will develop for the Sierra as well. These will bring lowering humidity and combine with the breezy winds to enhance fire weather concerns, especially Tuesday into early Wednesday.

Upper level ridge will build onto the West Coast for the second half of the week with somewhat less breezy winds and warmer temperatures. Halloween afternoon/evening looks dry and mild.

Extended Discussion (Friday through Monday)

The upper level ridge will be pushing to the east on Friday as a short wave trough tracks into the PacNW. This short wave will remain to our north and east only brining slight height falls to NorCal. This will keep the above normal temperatures in the forecast as we head into the weekend.

Another short wave trough will move into the PacNW on Sunday and this one does look to have a little bit more moisture with it. Some of that moisture makes it south by Monday but we lack any good forcing. This will keep the forecast dry until Monday night when we see a cold front push south into the region. Currently rain chances with the cold front only look minor though with only slight chances far north.