textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 120 PM PDT Sat Jul 18 2026

- Near or slightly below normal temperatures and higher humidity through the first half of the upcoming week.

- The marine layer and mid to upper level cloud cover will continue to help keep temperatures cooler under building high pressure.

SHORT TERM

Issued at 109 AM PDT Sun Jul 19 2026 (Today and tonight)

Onshore winds are ushering stratus inland. Onshore winds continue due to a 2.9 mb SFO-SAC pressure gradient. A few patches of mist/fog may additionally develop through daybreak. High clouds are extending far north-northeast of tropical storm Elida located 1000 miles south- southwest of Point Conception. Elida is forecast to essentially move northward, get drawn into the westerlies and weaken to a post tropical remnant low by 5 am PDT Tuesday, July 21st per latest from the NHC.

Strong (warm core) high pressure remains located over the interior west, land locked as typically this time of year due to high sun angle surface heating. The high is surrounded by a mix of cold core (mid-latitude) and warm core (tropical) low pressure systems of varying strength. Upward vertical motion/expansion (lows) has to return downward/compression (highs) somewhere via continuity. Upper level troughing generally remains located over the eastern Pacific. Daytime highs today will be about the same it was on Saturday, varying from the mid to upper 60s along the coast to the 70s bayside to the 80s and 90s well inland. Tonight lows will cool to the 50s except in the 60s in the hills and mountains.

LONG TERM

Issued at 109 AM PDT Sun Jul 19 2026 (Monday through Saturday)

As mentioned, current tropical storm Elida is forecast to move generally northward, get drawn into the westerlies and weaken to a post tropical/remnant low by early Tuesday. Tropical cyclones depend on a minimum of 80F or warmer sea surface temperatures. With less heat flowing into northward moving tropical cyclones the thermodynamic system diminishes. Not to mention northward moving tropical cyclones eventually encounter the westerlies, wind shear, drier air (destructive to convection), but may temporarily form in to a hybrid system or become an extra-tropical cold core system tapping energy transformation from warm/cold air temperature advection. As of current time, the GFS and ECMWF for example forecast the remnant low to pass ~ 500 miles to our west early-mid week, rain is forecast to fall from the low, but of course it'll be too far to our west to benefit from it. Good news so far, based on the forecast low trajectory and most model forecasts, there is minimal convective potential over our forecast area early-mid week. Of course as always stay tuned to the latest updates.

MARINE

(Tonight through next Friday) Issued at 952 PM PDT Sat Jul 18 2026

Winds continue to decrease overnight with a moderate northwesterly breeze to prevail into next week. Moderate seas prevail through the forecast. Moderate southerly swell will increase from tropical cyclone activity across the eastern Pacific through next week.

MARINE

(Tonight through next Friday) Issued at 952 PM PDT Sat Jul 18 2026

Winds continue to decrease overnight with a moderate northwesterly breeze to prevail into next week. Moderate seas prevail through the forecast. Moderate southerly swell will increase from tropical cyclone activity across the eastern Pacific through next week.

FIRE WEATHER

Issued at 120 PM PDT Sat Jul 18 2026

Cooler than normal temperatures with assistance from onshore flow and relatively normal diurnal intrusion of the marine layer will continue through the weekend into next week. RH recovery will be excellent for coastal areas and valleys, and moderate to good farther inland. However weak offshore flow/thermal belting will result in poor RH for higher elevations, especially above 1500- 2000ft across the East Bay Hills and Santa Lucias.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory until 3 AM PDT Sunday for Pt Arena to Pt Reyes 10-60 NM.