, Issued at 142 AM PST Fri Feb 27 2026 (Today and tonight)
The 00Z sounding observed an 850 mb temperature of 13.00 degrees Celsius which is above the 90th percentile (12.8 degrees Celsius) for the date and time. Upper-level shortwave ridging will get pushed into the region today by an upper-level cutoff low on its heels. At the surface, high pressure across the Intermountain West and a coastal trough off the California Coast will generate light offshore flow. All of the above will be contributing factors to temperatures climbing to 15 degrees above normal. Today will be the warmest day of the week and the warmest day of the forecast period. To limit heat-realted impacts, people should increase water intake, reduce time spent outdoors or stay in the shade when the Sun is the strongest, and open windows at night and use fans to bring cooler air inside buildings. To put this heat into context, SJC maximum temperature is forecast to be 78 degrees (previous record 79 degrees set in 1932, 1972, and 2020).
..issued at 407 AM PST Fri Feb 27 2026 (Saturday through Thursday)
Heights begin to fall Saturday as the upper-level cutoff low comes into the periphery. This will kickoff a brief, slight cooling trend; however, temperatures on Saturday will still be ten degrees above normal. Slight (15%) chances for precipitation remain Sunday into Monday with the passage of the upper-level shortwave trough - chances will be greater the farther north the location. Global ensemble clusters generally keep us dry with less than 0.10" for the wettest solutions. Even if it doesn't rain, an increase in cloud cover is expected with coastal drizzle possible. Conditions will be noticeably cooler with the return of near normal temperatures and onshore flow. There's also a less than 10% chance for thunderstorms. The three ingredients necessary for thunderstorm development of lift, instability, and moisture will be present, albeit with low CAPE (accompanied by CIN) and conditionally unstable lapse rates. The limiting factor in this case will likely be them not aligning spatially and/or temporally as depicted in point forecast model soundings. Upper-level shortwave ridging will nose in from the Eastern Pacific Ocean on Tuesday before quickly getting shoved eastward by a following upper-level shortwave trough that will dig into the Great Basin. Sensible weather wise this will translate to near to slightly above normal temperatures for the end of the forecast period.
(12z TAFS) Issued at 331 AM PST Fri Feb 27 2026
It's VFR at the airports. A patch or two of mist/fog may develop in the North Bay valleys this morning, otherwise high clouds continue to move through a strong 500 mb height ridge.
Vicinity of SFO, VFR. Light and variable wind periodically light northeast today.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR. East to southeast winds 5 to 10 knots becoming northwest 10 knots mid to late afternoon. East to southeast winds 5 to 10 knots tonight and Saturday morning.
(today through Wednesday) Issued at 322 AM PST Fri Feb 27 2026
Mostly light winds are expected across the waters through the weekend and early next week. Localized fresh gusts will affect the southern waters today but look to dissipate into the weekend. Low to moderate seas continue into next week. There is a chance of drizzle to light rain across the northernmost waters this weekend.
Ca, None. PZ, None.
