, Issued at 1123 PM PDT Wed Jul 15 2026 (Tonight through Friday)
Fortunately our weather balloons have returned to service with the 00Z launch, so let's look at some of the data. The 850 mb temperature is 22.75 C, which is between the 75th and 90th percentile for this time of year. That explains why it's been warm recently. The temperatures Wednesday weren't as hot as Tuesday, but still around 5- 10 degrees above normal. The PW has dropped to 0.65", or between the 25th and 50th percentile. So the monsoon moisture from last weekend is totally gone. The skies are still clear as the marine layer struggles to reform. Temperatures will be another 5-10 degrees cooler on Thursday, broadly similar to seasonal normal, as the 850 mb temperature drops a bit and onshore winds increase to bring cooler marine air advection. While temperatures are coming down, afternoon winds will be moderate to strong along the coast and in the mountains again today, bringing another round of elevated fire weather conditions.
It's unclear if marine layer clouds will form this morning. The SFO- SAC gradient is +4.0 mb, so the onshore flow is good, but there are no low clouds offshore at the moment. That means the stratus will have to form overhead, rather than advect in from the ocean like normal. I'll put it at a 25% chance for coastal stratus by sunrise, and even less chance of pushing inland. If the clouds do form, they will clear by late morning.
..issued at 1123 PM PDT Wed Jul 15 2026 (Friday night through next Wednesday)
It looks much more likely that the marine layer clouds will return Friday morning thanks to sustained onshore winds and a slowly approaching trough off the coast. The marine layer depth will likely grow to around 1,000 feet by then, enough for the morning stratus to reach into the valleys a bit. In addition to the clouds, the marine layer will keep coastal areas much cooler than they have been this week, and help regulate fire weather concerns. Once we get back into this cooler, marine layer pattern it looks like it's here to stay for a while.
Tropical Storm Elida has formed in the Eastern Pacific. This system will move harmlessly into the open ocean through the weekend, but some of the mid and upper level moisture is likely to be drawn into our southwesterly flow at 500 mb. This will be apparent with mid and/or upper level clouds arriving Sunday. Model soundings suggest that the atmospheric stability will prevent any thunderstorm chances, so this tropical moisture will most likely just be a good sunset maker with a couple novelty rain drops possible Sunday - Tuesday.
(12z TAFS) Issued at 431 AM PDT Thu Jul 16 2026
Currently VFR at all terminals. There is a patch of stratus that has developed within the Monterey Bay over the last 2 hours that continues to expand. If this reaches the Monterey Bay terminals, it will clear by late morning. A shallow marine layer around 1,000 feet is expected tonight. As such, moderate to high confidence on IFR ceilings returning to coastal and bayshore terminals with confidence decreasing as you move inland. Diurnal winds will prevail.
Vicinity of SFO, Currently VFR with northwesterly flow. Moderate (60%) confidence on an IFR ceiling returning tonight. The TAF may be slightly pessimistic with a 09Z arrival. Reasonable best case scenario is the marine layer is too shallow to make it through the San Bruno Gap and has to go through the Golden Gate Gap. This would likely lead to a later arrival time or stratus remaining confined to the north of the terminal. There's a 25% chance for wind gusts to reach 35 knots this afternoon and evening.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Currently VFR with southerly flow at MRY and VFR with northerly flow at SNS. Patchy stratus in the Monterey Bay is expanding within 5 miles to the north of the terminals. If this is able to reach the terminals, it'll likely be IFR and clear by late morning. High confidence on IFR ceilings returning to the terminals tonight with a greater chance at MRY than SNS.
(today through Tuesday) Issued at 431 AM PDT Thu Jul 16 2026
Fresh to strong northwesterly breezes will bring widespread hazardous conditions for small craft today. Localized gale force gusts are expected along the coastal jet regions of Point Reyes and Point Sur. Moderate to rough seas will prevail through Friday. Conditions improve Saturday as seas abate and northwesterly breezes diminish.
Ca, None. PZ, Small Craft Advisory from 9 AM this morning to 9 PM PDT this evening for Mry Bay-SF Bay N of Bay Bridge.
Small Craft Advisory until 9 AM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 AM PDT this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Gale Warning from 9 AM this morning to 9 PM PDT this evening for Pt Pinos to Pt Piedras Blancas 0-10 nm.
