FXUS66 KMTR 141714 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 1014 AM PDT Sat Sep 14 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 310 AM PDT Sat Sep 14 2024 Cooler temperatures persist, with rain chances arriving late Sunday. Rainfall will be minimal, and ends Monday afternoon. Another chance for rain arrives towards the midweek. Ridging and warmer weather on the horizon for next weekend. && .UPDATE... Issued at 846 AM PDT Sat Sep 14 2024 Extensive stratus coverage continues across the San Francisco and Monterey Bay regions, into the Salinas Valley, the Napa Valley, and the Gilroy-Hollister area. Inland stratus should gradually mix out through the day. The focus of the forecast period remains the systems set to come to our state starting tomorrow and lasting through Wednesday. See the previous discussion for more details. No updates to the forecast at this time. DialH && .SHORT TERM... (Today and tonight) Issued at 310 AM PDT Sat Sep 14 2024 Stratus has returned to much of the Central California coastline, painting a much different picture than the previous night in which the coastline was bare. The Salinas valley and Monterey Bay are coated in a sheet of white as the stratus pushes in. Meanwhile, it is clear and cool inland with current temperatures sitting in the 50s and 60s for most locations. Low pressure continues to dominate the stage over the weekend and extending into the long term. Cooler, more seasonal temperatures are expected once again today with highs generally in the mid to upper 80s for the interior, and 70s around the SF Bay. Highs in the low 60s will be the theme for the coastline. Breezy onshore winds will increase in the afternoon, and continue into the nighttime of Saturday into Sunday. In this overnight period tonight, winds will slowly increase as a cold front approaches, associated with an approaching low pressure system out of the northwest. However, the strongest winds will occur Sunday afternoon and evening with gusts in lower elevations reaching 25-30mph, and in higher elevations, 35- 45mph. So hold on to your hats and fold up those patio furniture umbrellas (lest you should want to recreate a scene from Mary Poppins)! It'll be a bit windy Sunday before and after the frontal passage, so take some extra consideration this weekend to perhaps just bring in anything that can be easily blown over. As of now, no wind products are necessitated. Just be aware of what is in the forecast! Though, winds are not all. As we've said before, and will say again here, there does exist the chance for rain with this system. Any rain that does fall will not be much, but it will be just enough to wet the ground and perhaps bring about that lovely post-rain smell, known as "petrichor." Bet you didn't know that that had a name! Well now you do, and now I managed to write one more sentence in this AFD on the midnight shift. Fun facts aside, the first chances of rain arrive very late Sunday, with the best chances just prior to sunrise on Monday. The wettest spots, which are likely to be the Santa Cruz mountains, may see up to 0.10" at most, with most other locations just seeing a few hundredths of an inch. Not much, for as discussed in last night's AFD, this storm system just is not carrying that much moisture with it. All in all, it'll be a nice break from the mundane of clear skies and warm weather, but not a washout by any means. && .LONG TERM... (Sunday through Friday) Issued at 310 AM PDT Sat Sep 14 2024 In the afternoon Monday, the rain chances cease, and things dry out a bit for a few days. High temps will be about 15 degrees below normal with highs only in the 60s for most locations. Things begin to warm up again Tuesday with highs in the 70s for the interior as the low pressure system moves out of the region to our northeast. Another low pressure system moves in Wednesday, bringing the next chances of rain. Similar to the one previous, it does not appear to bring much in the way of moisture, with total rainfall amounts only in the hundredths once again. Thursday, chances of rain end, and our continued pattern of troughing perhaps as well. Towards the end of next week, models point towards troughing being replaced by a ridge. This ridging is in agreement with current CPC 8-14 day outlooks, which indicate temperatures returning to a state of being slightly above normal, to near normal for our region. Ensemble guidance also points to ridging developing in the longer term. So, stay tuned, as warmer weather isn't quite out of season yet. The coming days will reveal just how warm temperatures will become. && .AVIATION... (18Z TAFS) Issued at 1012 AM PDT Sat Sep 14 2024 A cold front will sweep across the region from northwest to southeast overnight and through the morning hours with the highest wind speeds and precipitation delayed until the next TAF cycle. With the incoming unseasonably low upper-level low, the current marine layer of 1,800 feet is expected to deepen, therefore impacting more terminals as it is able to protrude further inland. High confidence in all terminals developing low-end MVFR ceilings overnight with the Monterey Bay terminals further deteriorating to IFR. Vicinity of SFO...High confidence in a low-end MVFR ceiling impacting the terminal overnight through Sunday morning. Winds will remain elevated through the TAF period ahead and through the cold frontal passage tomorrow, becoming gusty tomorrow morning. SFO Bridge Approach...Low clouds will filter in by 06Z and linger through Sunday morning. Monterey Bay Terminals...High confidence in IFR ceilings impacting both terminals early this evening through the end of the TAF period. Ceilings may further deteriorate to LIFR, but the forecast deepening of the marine layer may counteract that. In addition, the deepening of the marine layer will aid in visibilities dropping to IFR at worst. && .MARINE... (Today through Thursday) Issued at 1012 AM PDT Sat Sep 14 2024 Moderate to fresh northwesterly breezes will prevail today. A cold front will move through tomorrow ahead of an unseasonably cold upper-level low, resulting in widespread strong to near gale gusts. With this comes renewed chances for rainfall and a 10% chance for thunderstorms. A reinforcing upper-level low swings through on Wednesday posing the same hazards of gusty winds, rainfall, and a 10% chance for thunderstorms. Seas will be moderate with rough seas building in the outer waters in tandem with the passing upper-level lows. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 AM to 9 PM PDT Sunday for SF Bay N of Bay Bridge. Small Craft Advisory from 9 AM to 9 PM PDT Sunday for Mry Bay- Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory from 3 PM this afternoon to 9 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory from 9 PM this evening to 9 PM PDT Sunday for Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 PM PDT Sunday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...AC LONG TERM....AC AVIATION...Sarment MARINE...Sarment Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea