Sunrise 6:08 AM   Sunset 8:04 PM Moonrise 3:14 AM   Moonset 3:22 PM

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PZZ530 San Pablo Bay, Suisun Bay, The West Delta And The San Francisco Bay North Of The Bay Bridge- 845 Pm Pdt Fri May 3 2024
Tonight - W winds 10 to 20 knots with gusts up to 25 knots - . Becoming sw with gusts up to 30 knots after midnight. Rain after midnight. Sat - W winds 15 to 25 knots. Rain.Sat night - W winds 10 to 20 knots with gusts up to 25 knots. Sun - W winds 10 to 15 knots. Sun night - W winds 10 to 15 knots with gusts up to 25 knots. Mon - W winds 10 to 15 knots. Mon night - W winds 10 to 15 knots. Tue - NW winds 10 to 15 knots. Wed - NW winds 10 to 15 knots.

PZZ500 845 Pm Pdt Fri May 3 2024
Synopsis for the central california coast and bays including the Monterey bay - Greater farallones - .and cordell bank national marine sanctuaries - .
expect breezy to gusty northwest winds to continue with gale force gusts possible over the southernmost zones. This evening, a low pressure system and associated cold front will arrive from the north, bringing rain and moderate to fresh breezes across the waters. Winds will turn briefly southwesterly ahead of the system early Saturday morning, but turn to become northwesterly once more in the late part of Saturday morning. Rain ceases late in the day Saturday, and winds ease to become moderate into the new workweek.

FXUS66 KMTR 040807 AFDMTR

Area Forecast Discussion National Weather Service San Francisco CA 107 AM PDT Sat May 4 2024

New SYNOPSIS, SHORT TERM, LONG TERM

SYNOPSIS
Issued at 1201 AM PDT Sat May 4 2024

A cold front will bring rain, strong winds, and much colder temperatures to the area today. A gradual warming trend will start Monday with dry weather and plenty of sunshine next week.

SHORT TERM
(Today and tonight)
Issued at 1201 AM PDT Sat May 4 2024

KMUX is starting to pick up on the main frontal rain band as it approaches the North Bay early this morning. To add timing precision, I used a blend of high-resolution short term models to create 1 hourly PoP grids. Based on the new official forecast, rain is expected to reach Santa Rosa by 4 AM, San Francisco by 6 AM, San Jose by 8 AM, and Salinas by 10 AM. The main band of rain should last 6-8 hours before tapering off. The expected total rainfall is continuing to tick up slightly, with 0.5-1.0" in most lowlands and 1.0-1.5" in the coastal mountains. Prefrontal SW winds are moderate this morning, but will increase to a strong breeze as the front approaches and switch to a NW direction after it passes.

The confidence in the prefrontal stratiform rain described above is quite high, with very little ensemble spread. The bigger question today is if thunderstorms will develop in the cold, post frontal environment. The expected 700 mb temperature is near the daily minimum, which would suggest some instability, but there's a few complications. First, the coldest mid-level air doesn't settle in until Saturday night, after the surface temperature is on the down swing. Second, the 500 mb temperature is not as impressive as the 700 mb temperature with a more stable 3.5 C/km lapse rate between those two levels. This indicates any convection that initiates tomorrow will have a vertical limit of about 10,000 ft.
With the top end of the hail growth zone (-30C) at over 22,000 ft, this limits the amount of ice that will be generated. The most likely scenario is that after the front moves through some isolated, low-topped convective showers will pop up through the evening. There is a scenario, however, where the skies clear after the front passes and the surface temperature increases more than expected. This could lead to some evening thunderstorms, particularly in the North Bay where the front will clear first and the potential surface heating is higher. To demonstrate this, I adjusted the NAM model sounding at Santa Rosa, increasing the surface temperature a few degrees to line up with our forecast of 13C/55.4F. This alone increased the CAPE from 130 J/kg to over 500 J/kg. If the surface temperature exceeds our expectations, the instability will be even higher. In other words, if the sun comes out in the afternoon, the chance for evening thunderstorms increases significantly.

LONG TERM
(Sunday through Friday)
Issued at 1201 AM PDT Sat May 4 2024

The cold front and associated low pressure system will clear the area by Sunday, leaving cold air in place. Sunday morning will be on the chilly side, with many inland areas dropping into the upper 30s or low 40s. There is a slight chance for some lingering showers on Sunday, but they should be isolated and on a decreasing trend through the day (if anything develops in the first place).
Otherwise a gradual warming trend will kick off next week with Sunday highs in the 50s and 60s and Friday highs in the 70s and 80s. Expect lots of sunshine with breezy winds along the coast, especially during the first half of the week.

AVIATION
(06Z TAFS)
Issued at 942 PM PDT Fri May 3 2024

MVFR/IFR level clouds are moving inland. Winds are reducing and are expected to become light to moderate, then slowly turn to become more S/SW ahead of the approaching low pressure system. By the mid morning, most terminals will see winds increase once more to become breezy and gusty out of the SW, and rain begins, lowering visibilities at terminals. Cloud decks are expected to improve to lift slightly as the rain approaches. Rain continues into Saturday afternoon before dissipating, with winds turning to W/NW and becoming breezy. Expect these breezy winds to last into Saturday night.

Vicinity of SFO...IFR and breezy into the night. Winds reduce further into the night and turn southwesterly. These winds become gusty as the rain arrives early Saturday morning with MVFR CIGs and slight reductions in visibility. Winds turn to become W/NW in the later morning, but rain lasts through the afternoon. VFR returns behind the rain band, with breezy westerly winds.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR/LIFR CIGs last through the majority of the overnight hours with lighter winds. As the rain band arrives, expect CIGs lift to become IFR/MVFR late Saturday morning. Gusty westerly winds build along the rain band. VFR returns behind the main rain band with breezy winds easing into the late night.

MARINE
(Tonight through next Thursday)
Issued at 907 PM PDT Fri May 3 2024

Expect breezy to gusty northwest winds to continue with gale force gusts possible over the southernmost zones. This evening, a low pressure system and associated cold front will arrive from the north, bringing rain and moderate to fresh breezes across the waters. Winds will turn briefly southwesterly ahead of the system early Saturday morning, but turn to become northwesterly once more in the late part of Saturday morning. Rain ceases late in the day Saturday, and winds ease to become moderate into the new workweek.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-SF Bay N of Bay Bridge.

Small Craft Advisory from 9 AM this morning to 9 PM PDT this evening for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Pt Arena to Pt Reyes 0-10 nm.

Gale Warning until 9 AM PDT this morning for Pt Pinos to Pt Piedras Blancas 0-10 nm.

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San Francisco
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Sat -- 03:09 AM PDT     1.22 feet Low Tide
Sat -- 04:13 AM PDT     Moonrise
Sat -- 06:09 AM PDT     Sunrise
Sat -- 09:13 AM PDT     4.76 feet High Tide
Sat -- 03:04 PM PDT     0.32 feet Low Tide
Sat -- 04:22 PM PDT     Moonset
Sat -- 08:03 PM PDT     Sunset
Sat -- 09:54 PM PDT     5.77 feet High Tide
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San Francisco, California, Tide feet

Golden Gate Bridge .8 mi E .
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Sat -- 01:57 AM PDT     -2.44 knots Max Ebb
Sat -- 04:13 AM PDT     Moonrise
Sat -- 05:20 AM PDT     0.01 knots Slack
Sat -- 06:09 AM PDT     Sunrise
Sat -- 08:10 AM PDT     2.78 knots Max Flood
Sat -- 11:02 AM PDT     -0.01 knots Slack
Sat -- 02:11 PM PDT     -2.64 knots Max Ebb
Sat -- 04:22 PM PDT     Moonset
Sat -- 05:30 PM PDT     0.01 knots Slack
Sat -- 08:03 PM PDT     Sunset
Sat -- 08:29 PM PDT     3.36 knots Max Flood
Sat -- 11:29 PM PDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION

Golden Gate Bridge .8 mi E ., San Francisco Bay, California Current, knots

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