Marine Weather and Tides
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.
|Sunrise 6:47AM||Sunset 5:01PM||Tuesday November 13, 2018 7:36 PM PST (03:36 UTC)||Moonrise 12:16PM||Moonset 10:30PM||Illumination 35%|
7 Day Forecast for Marine Location Near Point Arena, CAHourly EDIT Help
Area Discussion for - San Francisco/Monterey Bay Area, CA  (on/off)  Help NOTE: mouseover dotted underlined text for definition
|Fxus66 kmtr 140052|
area forecast discussion
national weather service san francisco bay area
452 pm pst Tue nov 13 2018
Synopsis Smoke over the region will continue to result in poor
air quality through at least midweek with dry conditions and
light offshore winds. Seasonably mild, dry conditions will then
persist through the upcoming weekend. A pattern change will
potentially bring rainfall to the region around thanksgiving.
Discussion As of 02:00 pm pst Tuesday... Synoptic pattern
features an amplified upper level ridge overhead with a closed
low over the southern plains and a broad trough in the eastern
pacific. A weak shortwave trough on the eastern side of this broad
trough is advecting high clouds overhead. These clouds have kept
temperatures cooler this afternoon areawide. Highs so far have
only been in the low to mid 60s in the bay area and points
northward, while santa cruz southward has seen temperatures in the
mid 60s to lower 70s. The difference in temperature between the
northern and southern half of the CWA is caused primarily by
smoke coverage. The bay area is still socked in by smoke and poor
air quality, with visibilities around 2 1 2 miles this afternoon
is several locations such as santa rosa, sfo, and oakland.
Meanwhile, the southern half of the CWA has been spared the worst
of the air quality issues. Expect smoke to persist across the bay
area through this week as winds remain weak, limiting mixing.
Surface winds will turn onshore Wednesday afternoon along the
coast, but this may not offer much relief as a large area of smoke
extends several hundred miles off the coast.
An upper level ridge and a weak surface pressure gradient will
keep winds light through the rest of the week. Winds will be
generally 10 mph or less with gusts below 15 mph. Relative
humidity remains low in the higher terrain, with relative humidity
mainly in the 10-30 percent range above 1000 feet. Poor overnight
humidity recoveries are expected through the rest of the week.
Due to the dry air and very dry fuels, near critical fire weather
conditions will continue. An increasing onshore component in the
surface flow will allow humidity to gradually increase along the
coast. Highs this week will be seasonably warm with 60s near the
coast and low to mid 70s inland. A limiting factor, but less
certain, will be aerial smoke coverage, with more smoke reducing
daytime heating potential. Lows will not be quite as cold as|
recent nights with the increase in moisture in the valleys.
Looking ahead to next week, the advertised pattern change remains
likely but details are still far from certain. Models are at least
in agreement that a low will move to our south on Monday and
Tuesday. This does not look to bring any precipitation, but it
opens the door for a broad trough to potentially drop far enough
south to bring rain to our area as it moves eastward from the
pacific. Models are not consistent run to run on the timing or
strength of the trough and precipitation, but both the GFS and
euro show precip sometime in the Wednesday to Friday timeframe
next week. As always with forecasts this far in advance, details
are likely to change. Bottom line is that a pattern change is
likely next week, and the potential for precipitation around
thanksgiving is increasing.
Aviation As of 4:52 pm pst Tuesday... Ongoing wildfire smoke is
obscuring horizontal and slant range visibilities to MVFR-ifr in
a stagnant weather pattern. Mid and high clouds are streaming in
from the west with a weakly amplified, but dry 500 mb trough, and
weakly divergent jet stream winds becoming replaced by 500 mb
ridging Wednesday that slowly weakens through late week.
Vicinity of ksfo... MVFR in smoke. Poor to very poor slant range
visibility. Light winds.
Sfo bridge approach... Similar to ksfo.
Monterey bay terminals...VFR-MVFR. Varying amounts of smoke.
Poor slant range visibility.
Marine As of 03:44 pm pst Tuesday... Generally light southerly
winds will continue tonight as an upper low pass by well to the
north of the region. Winds will transition back out of the
northwest tomorrow as high pressure builds back over the eastern
pacific. Light mixed swell will continue through mid-week before a
northwest swell arrives.
Mtr watches warnings advisories
Public forecast: st
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