Heavy rain, flash flooding and severe thunderstorms are expected tonight into early Thursday from southern Louisiana into western Georgia. An Enhanced Risk (level 3 of 5) of severe thunderstorms is in effect. Across the West, an atmospheric river will bring a heavy rainfall and flash flooding threat to central and southern California through Thursday. Heavy snow is forecast in the Sierra Nevada. Read More >
ZOA CWSU Discussion | KSFO TAF TDA | |
AWAITING CWSU INPUT | TAF TDA KSFO/KSQL METAR METARArea PIREPs PIREP |
|
Satellite | Webcams, Ceiling≤030 Prob | |
Webcams
|
SIERRA 03 Hour Forecast | SIERRA 12 Hour Forecast | SIGMETs |
TANGO 03 Hour Forecast | TANGO 12 Hour Forecast | |
ZULU 03 Hour Forecast | ZULU 12 Hour Forecast | |
Area Forecast Discussion | Forecast Maps |
878 FXUS66 KMTR 130005 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 405 PM PST Wed Feb 12 2025 ...New AVIATION... .SYNOPSIS... Issued at 330 PM PST Wed Feb 12 2025 Potentially major impacts from a strong storm system incoming tonight and lasting into Thursday. Local flooding and widespread damaging winds are the main threats through Thursday morning. Slight chance for thunderstorms Thursday afternoon. Drier conditions on Friday into the weekend. Potential showers for the North Bay on Sunday. && .SHORT TERM... (This evening through Thursday) Issued at 330 PM PST Wed Feb 12 2025 KEY POINTS * Flood Watch in effect 10 PM Wed to 10 PM Sat (area-wide) * High Wind Warning (coastal) and Wind Advisory (inland) in effect from 10 PM Wed to 10 AM Fri (coastal) * Widespread shallow landslides possible Thursday morning * Downed trees and power outages likely * Highest impact areas include Santa Cruz Mtns and Big Sur Coast * High Surf Warning in effect 3 PM Thu to 3 AM Sat METEOROLOGY: Major winter storm still on track to impact the region beginning tonight. Beautiful visible satellite representation of the storm currently centered about 1,000 miles to our northwest. One can clearly make out features such as the nearly stationary warm front draped along the CA coast, as well as the intense surface cold front wrapping into the storm from the south and west. The storm will continue translating southeastward guided by an intense 170 kt jet streak aloft. Latest advanced scatterometer pass over the storm from about 1 PM today shows estimated sustained surface winds of 40-45 kts, which is in line with latest forecast wind intensities. Current surface pressure has been analyzed at 986 mb as of 1 PM this afternoon. Expecting these winds to hold or slightly increase their intensity as the storm nears the CA coast and deepens to around 981 mb by late tonight. As the storm nears the coast tonight, rainfall will likely start out as a gradual warm frontal overrunning in which rain will be widespread, but only light to moderate in intensity, lacking the robust cold frontal processes and enhanced upslope moisture transport. Progressing further after midnight tonight, the warm front moves ashore and the cold front enters the North Bay, moving quickly down the coast through the early morning hours. This will be the period in which the heaviest rainfall rates will occur...on the order of 1.0 to 1.5 in/hr, especially in the Santa Cruz Mtns and Big Sur coast. In addition to the intense rainfall rates, damaging winds will be a factor through the morning hours as well. Once the mid-level trough axis comes ashore around midnight, the strong mid-to-upper level flow begins to impinge on the CA coast. 850 mb flow out of the southwest at 50 to 60 kts spreads across the region from north to south from about midnight in the North Bay to 11 AM along the Big Sur coast. This will likely result in surface wind gusts of 40 to 50 mph across the area, with coastal areas and higher elevations seeing gusts in the 60 to 70 mph range. Isolated areas along the coast and coastal mountain ridgetops may end up seeing gusts closer to 80 mph as the more intense winds mix down with the passage of the cold front. Behind the cold front, the environment remains supportive for thunderstorms well into the afternoon. Immediately after the cold frontal passage, any thunderstorms that initiate will likely be over powered by robust speed shear and limited instability. There will also be a bit of dry air mixing into the storm top level per RAP forecast soundings along the coast, so there is some limited downburst potential with a few storms that are able to stay intact along the coast. Beyond the morning hours, instability increases a bit as the surface warms slightly, and speed shear decreases a bit as well as the upper level jet start to move out of the region. This will likely provide a window of time where storm ingredients are better suited to lead to more prolonged updrafts and better potential for rotation should any storm deviate to the right of the mean storm motion. For more details on the severe threat, see spc.noaa.gov, which places us in a general risk for thunderstorms for Thursday. IMPACTS: General flooding impacts will begin in the North Bay as early as tonight and spread across the rest of the region shortly after midnight. It may appear as a slow start for those areas that start to see rainfall first, as it will mostly be associated with a warm/stationary front, thus not terribly heavy. However, after midnight, rainfall rates are expected to increase substantially with the passage of the main cold front. This will exacerbate flooding concerns, especially in the Santa Cruz Mtns and Big Sur coast. By the time the cold front moves through, soils will be nearly saturated in the Santa Cruz Mtns, so we do expect to see issues with quick runoff and shallow landsliding. Not only will this alone be an issue, but winds are expected to gust up to 60 mph (as high as 80 mph along the ridge of the SC Mtns). Combining the high winds with saturated soils is a recipe for downed trees and power lines, leading to potential structure damage and power outages. The Flood Watch has been expanded to cover the entire region, and the High Wind Watch has been upgraded to a High Wind Warning for coastal areas, and a Wind Advisory for inland areas. We will likely see notable rises on many major rivers, but the Russian River at Guerneville and the San Lorenzo River have the highest chances of going into flood stage. The San Lorenzo perhaps being one of the more worrisome ones given how flashy the terrain is known to be in that region. Other coastal areas outside of the Santa Cruz Mtns may not see the same degree of shallow landsliding, but nonetheless will still have impacts due to downed trees and powerlines, especially areas near the Marin headlands, Big Sur/Carmel coast, and Monterey Peninsula. The commute Thursday morning will undoubtedly be nasty and downright dangerous in some cases (thinking Hwy 17 in particular). When all is said and done, the North Bay will likely end up with 2 to 4 inches, and the Bay Area will see a range of 1.5 to 3 inches depending on if you`re in the South Bay rain shadow or not. The Santa Cruz Mtns and Big Sur coast will be the winners with 4 to 7 inches, locally up to 8-10. Despite some locations seeing some of the lower end of rainfall amounts, wind is still expected to pose a threat to life and property through Thursday. && .LONG TERM... (Friday through next Tuesday) Issued at 330 PM PST Wed Feb 12 2025 Shower activity will be coming to an end Friday morning with dry conditions into Saturday. Medium range ensemble guidance is showing the potential for another much weaker storm system on Sunday that would brush the North Bay, but the upcoming storm system this Thursday morning is the only majorly impactful period that we see in the 7 day forecast period. There will likely be a lull in storm activity along the West Coast through next week. && .AVIATION... (00Z TAFS) Issued at 404 PM PST Wed Feb 12 2025 A mixed bag of MVFR and VFR conditions as the storm system continues to move into our area. Some vicinity showers will occur until tonight where the heavier bands of rain will move over the terminals creating reduced visibility and low ceilings. CIGs and VIS may drop to IFR if rain intensifies overnight. There is a chance for low level wind shear/upper air turbulence across most terminals overnight into early Thursday morning. Rain will start to diminish towards Thursday morning but expect MVFR to prevail through the TAF period for all terminals. Winds will start to build into strong gusty southerly winds overnight and prevail through the rest of the TAF period. Vicinity of SFO...MVFR with light westerly winds. These winds will turn to southerly direction shortly after 00Z and will build to strong and gusty winds with a chance for AWW speeds near 10-11Z. LLWS/turbulence is possible as well with speeds up to 50-55 knots at 2000 feet near 10-11Z. High confidence that winds will overall remain strong and gusty through the remainder of the TAF period. As the rain becomes heavier, CIGs/VIS may drop to IFR conditions overnight. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR/MVFR conditions. Higher confidence that MVFR conditions will prevail after 06Z through the remainder of the TAF period. Southerly winds will build to strong and gusty with a chance of LLWS between 12-16Z. && .MARINE... (Tonight through next Monday) Issued at 330 PM PST Wed Feb 12 2025 Winds are increasing widespread gale conditions with isolated storm force gusts possible. Moderate period westerly swell will build through Friday morning with very rough to high seas expected. Light rain showers will continue through the day ahead of moderate to heavy rainfall that is expected Wednesday night through Friday morning with a slight chance for thunderstorms Thursday. && .BEACHES... Issued at 1101 PM PST Tue Feb 11 2025 A High Surf Warning is in effect from 3 PM Thursday through 3 AM Saturday for all Pacific Coast beaches. Westerly swell with a period up to 15 seconds will build through Friday. As a result, west-facing beaches will see dangerously large breaking waves of 20 to 30 feet and up to 45 feet peak waves, non-west facing beaches will see dangerously large breaking waves of 15 to 20 feet and up to 30 feet peak waves. Everyone should remain out of the water due to life- threatening surf conditions. Stay off of jetties, piers, and other waterside infrastructure, keep pets on a leash and away from the water, and never turn your back on the ocean! Sarment && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Flood Watch from 10 PM PST this evening through Saturday evening for CAZ006-502>506-508>510-512>518-528>530. High Wind Warning from 3 AM Thursday to 10 AM PST Friday for CAZ006-502-503-505-509-512-529-530. High Surf Warning from 3 PM Thursday to 3 AM PST Saturday for CAZ006-505-509-529-530. Wind Advisory from 3 AM Thursday to 10 AM PST Friday for CAZ504- 506-508-510-513>518-528. PZ...Gale Warning from 9 PM this evening to 3 AM PST Friday for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10- 60 NM-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge. Gale Warning until 3 AM PST Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 PM PST this evening for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm. && $$ SHORT TERM...Behringer LONG TERM....Behringer AVIATION...SO MARINE...Murdock 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 |
|
Yesterday | ⇛Visible ⇛Nighttime ⇛GeoColor+GLM | Today | |
24-Hour Temp Change | 24-Hour RH Change | ||
⇛Visible ⇛Nighttime ⇛GeoColor+GLM
Additional Links
National Airspace System Status
Other Webcams:
Alert California San Bruno Mountain
Alert California Sutro Tower 2
Alert California Coll of San Mateo Bldg36