FXUS66 KMTR 310036 AFDMTR Area Forecast Discussion National Weather Service San Francisco Bay Area 436 PM PST Mon Jan 30 2023 .SYNOPSIS...Frost and freezing temperatures are likely away from the coast and are even possible for some coastal areas through mid week. Warming by late week with rain chances returning. ...Frost and Freezing Temperatures Many Areas Tonight... .DISCUSSION...as of 12:04 PM PST Monday... This Evening through Wednesday: Upper ridging will build into the region as surface high pressure centers over the central Great Basin. This will set up a north to northeast wind pattern this evening with breezy conditions in the North Bay hills. A consensus of the high resolution model guidance then suggests these winds should weaken between 12-15Z (4-7 AM). So while the breeze should keep things somewhat mixed during the first portion of the night do expect winds to settle a bit heading towards morning. This setup once again implies some complexity to the temperature forecast and to which areas will fall, and how fast. Before getting into the details let's first state that it will be cold. Lows for most places will drop into the 30s, with 20s for the coldest interior valleys. So these readings will be hazardous to unsheltered individuals, pets, and sensitive plants. Most areas (outside of the warmest places immediately adjacent to the coast and bays) will see frost potential (below 35 degrees) with a freeze expected for some. Right now the highest confidence in seeing more widespread freezing temperatures is across San Benito County, within the Santa Clara hills, across the Santa Lucia range, and across far southern Monterey County. However freezing temperatures are also expected within wind sheltered locations (primarily inland) across the Monterey and San Francisco Bay areas, and within the Santa Cruz Mountains. Frost/freeze products are out to cover the temperature threat in a broad sense but do be aware given our complex terrain that results may vary locally with some spots dipping to freezing while others remain just a bit above. The key message is to check on people and pets, and cover or bring sensitive vegetation indoors. For tomorrow high pressure will dominate at the surface and aloft with quiet weather. High temperatures will warm a few degrees from Monday with low elevation highs generally in the upper 50s to around 60. The higher terrain will remain chilly with highs in the 40s. Look for a repeat on Wednesday with a frosty night followed by afternoon warming. Winds do appear a little lighter so lows Wednesday morning could even be a few degrees colder in the sheltered valley locations. So another night to protect people, pets, plants and pipes from the cold. Friday through Sunday: A progressive upper flow pattern will prevail with the storm track focusing a bit to our north. However we'll remain close enough for some rain chances, with the greatest potential across the North Bay. The first system should move through on Thursday night into Friday bringing modest rain amounts to the region. Portions of the Sonoma Hills and Santa Cruz Mountains may receive over 0.5 inches of rain with much lighter totals elsewhere. This system will quickly depart with another arriving on Saturday night into Sunday. This system also looks to bring modest amounts with the greater totals across the North Bay. Temperatures appear seasonal into early next week. && .AVIATION...as of 04:36 PM PST Monday...For the 00Z TAFs. VFR through the TAF period. Building high pressure is resulting in clear skies area-wide. Light to moderate winds generally out of the E to NE. Another burst of NE winds aloft tonight could bring some stronger gusts to North Bay terminals and possible LLWS. Other areas will continue to experience light offshore flow. Vicinity of KSFO...VFR. Winds have been remaining easterly and have diminished AOB 10 kt at KSFO and other area terminals. Expecting winds to remain offshore tonight, but may become more northerly later tonight, so overall low confidence in direction. Moderate confidence in winds staying AOB 10 kt tonight. Clear skies continue through the period. KSFO Bridge Approach...Similar to KSFO. Monterey Bay...VFR. Winds light and E to NE this evening, but NW may develop at KSNS. SE drainage winds overnight tonight into Tuesday morning. NW winds develop Tuesday afternoon. Clear skies prevailing. && .MARINE...as of 02:42 PM PST Monday...Gusty winds over the southern waters again tonight, and will begin to diminish into Tuesday morning. Winds remain relatively light through mid week, increasing again and becoming southerly on Thursday. Seas gradually diminish Tuesday into Wednesday, with a new northwesterly swell along with a storm system arriving Thursday. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...Frost Advisory...CAZ502>504-508-512-528>530 Freeze Warning...CAZ506-510-513>518 SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM && $$ PUBLIC FORECAST: SPM AVIATION: Lorber MARINE: Behringer 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