, Issued at 133 AM PDT Sun Mar 15 2026 (Today and tonight)
Satellite imagery is showing a band of stratus setting up at the immediate coastal region from Half Moon Bay down through Point Sur, with a finger of clouds extending from the Monterey Peninsula into the Salinas area. Model output is suggesting that some cloud development is possible along the San Francisco Bay shoreline overnight, but otherwise the region remains generally clear through sunrise with low temperatures across the region remaining in the middle 40s to middle 50s.
Today will mark the start of a major heat wave that will challenge or set all time records for the month of March -- more about that in the long term discussion -- as an anomalously strong ridge develops in the eastern Pacific and crawls into the state. It will certainly feel quite a bit warmer across the region as temperatures around 5 to 15 degrees warmer than those seen yesterday are expected, with highs in the 80s forecast across the inland valleys, the middle 70s to lower 80s near the Bays, and the middle 60s to middle 70s at the Pacific coast. Also note that the shallow marine layer that kept the immediate coastline cooler yesterday will further compress or even erode away as the ridge takes hold, allowing for substantially warmer conditions at the coastal regions. Winds will generally be light to gentle with a northerly component to the large scale flow.
Widespread Minor HeatRisk is expected today, corresponding to a low risk of heat-related illnesses for the most sensitive populations, including children, the elderly, pregnant women, those with chronic illnesses, and people working or living outdoors without adequate shelter or cooling. Remember to stay hydrated and allow time to rest in the shade during outdoor activities, and never leave children or pets unattended in the car!
..issued at 133 AM PDT Sun Mar 15 2026 (Monday through Saturday)
The ridge continues to trek across the state through the early part of the work week and will strengthen a little bit as the ridge axis begins to enter the Desert Southwest during the middle of the work week, where it will stall out for a couple of days. Model output is showing a possibility for 500 mb heights at OAK to exceed 5900 meters, which would set an all time record 500 mb height, for the entire month of March. As noted by the previous forecaster, the Wednesday to Friday timeframe is when we expect the warmest conditions to occur, when highs in the interior valleys reach the upper 80s to the upper 90s and the coastal regions range from the lower 70s to the middle 80s. We are even starting to see some areas of the Gabilan Range reaching triple-digit high temperatures for the Wednesday through Friday timeframe, and NBM probabilistic guidance continues to show low probabilities (around 10%) for triple digit highs in portions of the northern Salinas Valley, the foothills of the Berkeley-San Leandro Hills, and the interior East Bay valleys. Low temperatures during this period will range from the middle 50s to middle 60s across the lower elevations, to the upper 60s and lower 70s in the higher elevations.
This will be our first major heat wave of the year, where temperatures that feel more like late summer heat extend pretty much through the work week. Widespread Moderate HeatRisk is expected from Monday through Friday, with a moderate risk of heat-related illnesses for sensitive populations, while patches of Major HeatRisk, corresponding to a high risk of heat-related illnesses for the general population, are possible within the higher elevations of the Santa Cruz Mountains, the foothills of the Gabilan Range near Pinnacles National Park, to the east of Salinas, and the mountains surrounding Carmel Valley. To re-emphasize points made by the previous forecaster: Given the long duration of this heat event, susceptibility to heat related illnesses will increase throughout the week. If you are going to be outside for prolonged periods of time make sure you are drinking plenty of water and allowing time to rest in the shade. Never leave people or pets unattended in the car. If possible, avoid going outside during the peak afternoon heat (approx. 10AM - 4/5PM). A Heat Advisory will go into effect on Monday across the Bay Area and Central Coast, which will extend through Friday at the earliest with some potential for expansion into the following weekend.
In addition, the unseasonably warm heat will help dry the fine fuels across the region, elevating the potential for grass fires through the week. Offshore winds will remain light to moderate, which will help mitigate the growth of any fires that take hold. Anyone who is engaging in outdoor activities (including camping, hiking, and offroading) should exercise caution when using fires and open flames.
As for the longer term, ensemble model cluster analysis does show the ridge flattening as it starts to make its way into the southern Great Plains towards the upcoming weekend and beyond. The current forecast does show a cooling trend for the upcoming weekend, as "extraordinarily hot" becomes merely "pretty hot", but how fast that cooling trend takes hold will depend on how soon the ridge moves eastwards and how fast it flattens.
(12z TAFS) Issued at 426 AM PDT Sun Mar 15 2026
Spotty LIFR CIGs and VIS, mainly impacting HAF, MRY, and SNS, although APC has also been reporting some mist and fog at times this morning any time the wind dies. With a compressed marine layer across the Bay Area, there is very little chance for these impacts to reach SFO, OAK, or SJC, which should enjoy VFR conditions through the day. Otherwise winds will remain gentle to moderate and diurnally driven with offshore winds in the morning and stronger onshore winds in the afternoon.
Vicinity of SFO, No notable weather impacts expected today. There is a slight chance for mist Monday morning.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, For some reason the stratus has pulled off on MRY, but continues to fill the Salinas Valley. SNS is reporting 1/4 mi visibility in dense fog. It's unclear if the ceilings and fog will push back to MRY this morning. The current satellite trend doesn't show any forward progress, but with the cloud bank so close to the terminal I decided to include a tempo line to indicate the possibility. VFR conditions will prevail from late morning through the day after the marine layer stratus mixes out.
(today through Friday) Issued at 426 AM PDT Sun Mar 15 2026
A fresh to strong NW breeze will continue across the outer waters before the wind speed gradually decreases to a moderate breeze Monday and continues through mid week. Sea heights will stay moderate due to a combination of wind waves and low southerly swell.
Ca, Heat Advisory from 10 AM Monday to 8 PM PDT Friday for CAZ006- 502>506-508>510-512>518-528>530.
PZ, Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 9 AM PDT this morning for Pigeon Pt to Pt Pinos 10-60 NM.
