Sunrise 6:27 AM   Sunset 7:49 PM Moonrise 2:06 PM   Moonset 3:20 AM

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PZZ530 San Pablo Bay, Suisun Bay, The West Delta And The San Francisco Bay North Of The Bay Bridge- 814 Pm Pdt Thu Apr 18 2024
Today - SW winds around 5 knots - .increasing to 10 to 15 knots this afternoon. Tonight - SW winds 10 to 15 knots with gusts up to 25 knots. Patchy drizzle. Fri - SW winds 10 to 15 knots with gusts up to 25 knots. Fri night - SW winds 10 to 15 knots with gusts up to 25 knots. Sat - SW winds 10 to 15 knots. Sat night - W winds 15 to 20 knots with gusts up to 25 knots. Sun - W winds 10 to 15 knots. Mon - SW winds 5 to 10 knots.

PZZ500 814 Pm Pdt Thu Apr 18 2024
Synopsis for the central california coast and bays including the Monterey bay - Greater farallones - .and cordell bank national marine sanctuaries - .
expect light to moderate winds into the weekend before breezy to gusty northerly winds arrive Saturday afternoon that will increase hazardous conditions over the waters. Wave heights will start to build heading into the late weekend before diminishing by mid- week. Another moderate period northwest swell arrives over the weekend as well as another light, longer period (18 seconds) southerly swell.

FXUS66 KMTR 190614 AFDMTR

Area Forecast Discussion National Weather Service San Francisco CA 1114 PM PDT Thu Apr 18 2024

New AVIATION, MARINE

SYNOPSIS
Issued at 142 PM PDT Thu Apr 18 2024

A touch cooler Friday as a weak system moves through. Chance for light drizzle for coastal areas the next couple of days. Temperatures rebound late weekend and early next week. Chance for light rain enters the forecast mid next week.

UPDATE
Issued at 917 PM PDT Thu Apr 18 2024

Meso-scale models did a good job verifying a return of coastal stratus earlier today, however have since only picked up approx 50% of the full extent of the southerly SMX-SFO, SBA-SFO pressure gradients. Similarly it's true also regarding the ACV-SFO pressure gradient, the NAM typically is 1 mb too low between these two locations anyhow. The ACV-SFO, SMX-SFO and SFO-SAC pressure gradients have been/are similar in strength indicating general north-south convergence and onshore directed winds. The Fort Ord profiler shows the marine layer depth increasing to 1700 feet, the Bodega Bay profiler showing the depth steady near 1,000 feet. At and below the marine layer temperature inversion, sea surface temperatures, air temperatures and dew point temperatures (including above the marine temperature inversion where it's clear for nocturnal radiative cooling) remain conducive to night and morning stratus and fog development and with lower level cooling and gentle upslope flow, a few patches of coastal drizzle will likely continue. Daytime surface warming and mixing will erode the stratus and fog back close to the coastline. A greater push of cooler maritime air is forecast to reach far inland Tuesday.

On the other side of things, surface based convective potential over southeastern San Benito county quickly blossomed up to a thunderstorm with echo tops to 36 thousand feet during the late afternoon. Once formed the thunderstorm almost as quickly dissipated, but quite likely produced a decent downpour and possibly small hail; e.g. vertically integrated liquid approached but just stayed below low end double digits.

Current forecast looks good, please see below for more details.

SHORT TERM
(This evening through Saturday)
Issued at 142 PM PDT Thu Apr 18 2024

Increased cloud cover today along coastal areas south of SF as the marine layer deepens ahead of the approaching weak trough. Still looking like a progressive, open wave, this system will scoot through rather quickly Friday, bringing additional cloud cover and a slight chance for drizzle along coastal locations and higher elevations of the East Bay Friday and Saturday mornings. The other impact from this system will be the breezy NW winds that develop along the coast as the system departs. Generally looking at gusts of 25-30 mph along the immediate coast Saturday afternoon into Sunday afternoon.

LONG TERM
(Saturday night through next Wednesday)
Issued at 142 PM PDT Thu Apr 18 2024

By Sunday, ridging dominates the pattern once again with temps warming back into near 80 for inland areas and 60s to near 70 along the coast. Similar picture into Monday as well. Tuesday brings some changes. Ensemble guidance continues to advertise anomalous troughing over the EPac/West Coast during the mid-to- late next week period, hinting at a pattern that promotes above average precip and below average temperatures. Average precip for the second half of April for our region is roughly a half inch, give or take a few tenths depending on if you're coastal or inland. What we're expecting next week is generally on the order of a trace to a few tenths here and there. Longer terms guidance does show the pattern continuing into next weekend, where there could be additional light rainfall, bringing us into that ballpark of slightly above normal. The main caveat with this forecast is that while there is moderate to high confidence in the overall pattern, the confidence in widespread measurable rainfall is low. In fact, in a grouping of 100 different models, roughly 24 of them advertise any measurable precip for us at all through next weekend. The answer to the question of next week being widespread light rain or just some increased cloudiness and drizzle will need further refinement in future forecasts. For now, plan on the latter half of next week being cool and damp.

AVIATION
(06Z TAFS)
Issued at 1114 PM PDT Thu Apr 18 2024

A mix of predominantly LIFR and IFR conditions through the night tonight and the late morning of Friday. North Bay and Monterey Bay terminals are likely to see LIFR conditions persisting through the overnight hours and into the late morning as a result of fog and low stratus CIGs . Sinking, drier air aloft is likely helping to lower and squash CIGs down to around 1400 feet currently per the Bodega Bay profiler, and 1800 feet per the Ft. Ord profiler. Expect these CIGs to lower progressively through the night and into the morning hours. Terminals in the SF Bay region are more likely to see MVFR conditions per model suggestions, though confidence on this is only moderate, given the low CIGs elsewhere. A drop into IFR CIGs for SF Bay terminals overnight is not out of the question. Decent onshore flow overnight will also be a factor in helping advect stratus inland, leading to robust cloud coverage through at least the late morning of Friday. In the early afternoon, as things heat up, clouds should begin to mix out bringing a return of VFR conditions and breezy to moderate onshore winds.

Vicinity of SFO...SFO in particular overnight appears to remain the odd one out, as it is likely to remain in VFR territory, with good agreement among numerous models. Despite good onshore flow overnight around 6-7 knots, given the fact that the stratus deck currently sits around 1400' and is expected to lower, stratus may not be able to rise above and advect through the San Bruno gap, keeping conditions clear and VFR locally at SFO terminal. Additionally, any stratus that fills over the bay waters will be likely kept just on the periphery of the SFO vicinity as good overnight flow out of the west helps keep any stratus over the bay away and pushed more towards the KOAK side. KOAK conversely will likely see IFR conditions last through the nighttime as good overnight onshore flow helps push stratus through the Golden Gate gap and into the SF bay. Late clearing is expected at KOAK with VFR returning in the late morning to early afternoon.

SFO Bridge Approach...IFR-LIFR conditions are likely as robust stratus coverage develops overnight over the SF bay waters thanks to good onshore flow. Clearing expected into the very late morning to early afternoon of Friday to VFR.

Monterey Bay Terminals...IFR/LIFR through much of the night as a result of very low CIGs . Stratus is expected to continue to lower through the night. Some reductions in visibility are possible as CIGs lower and the air reaches saturation near the ground, leading to mist and fog development. However, confidence on mist and fog development is not as strong as confidence in CIGs lowering. This will be something to watch closely overnight. VFR returns in the early afternoon though a FEW-SCT low clouds may linger, with winds onshore and around 10 knots. Stratus makes an early return in the evening of Friday.

MARINE
(Tonight through next Wednesday)
Issued at 1114 PM PDT Thu Apr 18 2024

Expect light to moderate winds into the weekend before breezy to gusty northerly winds arrive Saturday afternoon that will increase hazardous conditions over the waters. Wave heights will start to build heading into the late weekend before diminishing by mid- week. Another moderate period northwest swell arrives over the weekend as well as another light, longer period (18 seconds)
southerly swell.

MTR WATCHES/WARNINGS/ADVISORIES
CA...None.
PZ...None.

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San Francisco
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Thu -- 02:58 AM PDT     2.26 feet Low Tide
Thu -- 04:19 AM PDT     Moonset
Thu -- 06:29 AM PDT     Sunrise
Thu -- 08:33 AM PDT     4.54 feet High Tide
Thu -- 03:06 PM PDT     Moonrise
Thu -- 03:06 PM PDT     0.48 feet Low Tide
Thu -- 07:49 PM PDT     Sunset
Thu -- 10:09 PM PDT     4.95 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

San Francisco, California, Tide feet

Golden Gate Bridge .8 mi E .
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Thu -- 02:31 AM PDT     -1.46 knots Max Ebb
Thu -- 04:19 AM PDT     Moonset
Thu -- 05:06 AM PDT     0.01 knots Slack
Thu -- 06:29 AM PDT     Sunrise
Thu -- 07:58 AM PDT     1.85 knots Max Flood
Thu -- 10:22 AM PDT     -0.01 knots Slack
Thu -- 02:05 PM PDT     -2.26 knots Max Ebb
Thu -- 03:06 PM PDT     Moonrise
Thu -- 05:26 PM PDT     0.00 knots Slack
Thu -- 07:48 PM PDT     Sunset
Thu -- 08:38 PM PDT     2.83 knots Max Flood
Thu -- 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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