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What makes it blow at Sherman?
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lfsk



Joined: 27 Mar 1995
Posts: 18

PostPosted: Tue Jun 19, 2007 2:22 pm    Post subject: What makes it blow at Sherman? Reply with quote

Can anyone enlighten me as to what to look for in the weather pattern to help predict wind at the delta? Looking at the graph for the past 7 days, its all over the place with today (tues 6/19) being raging all morning so far (its noon right now). I live in So Cal so please don't tell me to look for fog in the city, I'm not in the city. Something I can look at on the weather pages online, like temp differences and gradients. Planning a trip after the July 4 holiday, just want to know. Thanks!!
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boggsman1



Joined: 24 Jun 2002
Posts: 3562
Location: at a computer

PostPosted: Tue Jun 19, 2007 2:39 pm    Post subject: Shermy Reply with quote

Fog in the BAY is the indicator. If you dont live here, call someone who does. The Marine surge off the coast , combined with valley heat creates a big pressure gradient.
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tthole



Joined: 08 Oct 2002
Posts: 54

PostPosted: Tue Jun 19, 2007 3:09 pm    Post subject: Sherman Reply with quote

The best way to find out about the fog if you don't live here is www.sfgate.com the weather section, look for fog on the forcast and scroll down to the marine forecast section. It is usually quite accurate for instance today is right on.

Cheers, Tim
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whinston



Joined: 18 Apr 1999
Posts: 8

PostPosted: Tue Jun 19, 2007 3:34 pm    Post subject: Reply with quote

These web cams give you a real time look at the extent to which the bay is socked in. They're another good tool for predicting conditions at crissy, northern peninsula sites and sherman.

http://cbs5.com/webcams/local_slideshow_027212125/view?slide=0
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beallmd



Joined: 10 May 1998
Posts: 1074

PostPosted: Tue Jun 19, 2007 5:00 pm    Post subject: Reply with quote

the forecast for dummies is the difference between san francisco temperature and sacramento. if SF is around 70 degrees and Sacramento is around 90 to 95 that is the gradient. If San Fran is 76 or higher may not be any sailing in Bay Area. If Sac is 100 or more, same thing. when Antioch warms to 95 or a 100 it is all over. Antioch is closest weather report to the sailing there but reads low compared to the delta. the delta wind can be very localized right at Sherman island area. that is the simplest way to look at it.
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harris52



Joined: 11 May 1998
Posts: 121

PostPosted: Tue Jun 19, 2007 5:21 pm    Post subject: Reply with quote

also watch for very hot weather patterns. This often blows off with the fog rushing back in. If there's a heat wave, start packing and watch the forecast carefully.
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thirsty



Joined: 10 Apr 2000
Posts: 6

PostPosted: Wed Jun 20, 2007 1:28 am    Post subject: Reply with quote

I've found that the best thing to do is look at the daily high temperature forecasts for Sacramento. If the temperatures in Sacramento are going down significantly there will be wind; if the temperatures are going up there won't be as much wind.
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coachg



Joined: 10 Sep 2000
Posts: 2003

PostPosted: Wed Jun 20, 2007 9:39 am    Post subject: Reply with quote

I agree with thirsty because I live in Sacramento. If our temps are going up it means NW wind in Sacramento which tends to reduce or shut down Sherman. If our temps are going down it is because the cool delta breeze is blowing in form Sherman. When Sacramento is running in the high 80's to low 90's you can bet Sherman is blowing.

Besides, if you are not a wind snob, you can sail just about every day at Sherman duing the on season. Let's see, 14 mph at Sherman or 22 mph at Crissy? An extra hour and change to drive + gas + bridge toll + wetsuit + parking and oh yeah, bumper to bumper traffic. I guess I'll just grap a bigger sail and go to Sherman.

Coachg
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aikimatt



Joined: 22 Jul 2000
Posts: 16

PostPosted: Wed Jun 20, 2007 10:57 am    Post subject: Some damn nerdy stuff.... Reply with quote

The Delta is my home spot, so I just check the sensor and go if it's windy, but I still keep my eyes open so I can know if it's worth setting the alarm early.

A big temperature gradient seems to be important, as most are saying. (Though right now in the morning the temperature gradient is minimal and it's blowing stink in the Delta.) Also a good pressure gradient between SFO and SAC - at least one millibar and preferrably at least two if you have long to drive. Also south to southwest flow and inversion on the coast. Also fog at least to Alcatraz.

Don't get mad if it happens when not all of these ingredients are there, this is just the setup that causes your typical good Sherman day. Also be warned that "fog in the bay" is really bad to use as a predictive instrument. It can be socked in at one moment and totally blow off within two hours. The fog has support if there is southwest flow on the coast.

Here's how to check it out:

Fog:
The last is perhaps the most useful. You can look at the historical satellite photos and see the marine layer pressing up the coast from the south and into the bay. If it's still "pressing" and not holding still or rolling back then that's a good sign. "Ribbons" streaking from SW to NE above more stagnant action below is also good if it's warm enough. Usually you just see the tongue of marine air. You can also check this out after you go home when it scours out to nothing overnight and you get skunked to see exactly why fog is not a predictive indicator.
http://www.bereleycam.net
http://sv.berkeley.edu/view/
http://www.nrlmry.navy.mil/sat-bin/display10.cgi?SIZE=full&PHOT=yes&AREA=pacific/eastern/monterey_bay&PROD=vis&TYPE=ssmi&NAV=epac_westcoast&DISPLAY=Latest&ARCHIVE=Latest&CGI=epac_westcoast.cgi&CURRENT=20070605.1630.goes11.vis.x.monterey_bay.x.jpg&MOSAIC_SCALE=15

Southwest flow and inversion:
These are really useful once you figure out how to read them. Each column is a slice of time. The past is on the right, the present is the left edge. The wind barbs are standard (each tick is 10 knots, half a tick is 5, ticks on the side the wind is coming from) and stack up to show you the wind speed and direction at various heights. Temperature is indicated by color. What we want to see is a real thick or at least growing layer of blue at Ft. Ord, best if it's got the "yellow" warmer air on top of it. Bodega may be all yellow if the pattern is just emerging, but if you see strong NW surface wind at Bodega then be a little bit wary. If you see warm air under cold air then you should seriously reconsider any kind of long drive. Cold air under warm air, though, is the inversion we're looking for.
http://www.weather.nps.navy.mil/profiler/bby_915.gif
http://www.weather.nps.navy.mil/profiler/ord_915.gif

Pressure and temperature:
I don't really check these as much as the others, so I don't have links for them. Try http://nws.noaa.gov plus some poking around. I don't want to play down how important that pressure gradient is; it's just that during building or steady southwest flow there's bound to be a good pressure gradient.

If you really want to predict in the big picture you need to guess whether, at what time, and from what angle the low pressure systems coming from northwest of the bay area are going to attack and also when they are going to make their exit. The best computers and professional meteorologists seem to still be very bad at this, especially the timing part.

Why not just quit your job, buy a camper, and move to the Sign? Then you'll be sure to catch it all.
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izitwindy?



Joined: 10 Jun 1998
Posts: 44

PostPosted: Wed Jun 20, 2007 11:16 am    Post subject: Reply with quote

its all about the pressure gradients AND the fog..If your E-W gradient is weak as compared to the N-S gradient, the wind cannot get far enough into the bay to ramp up Sherman...the other thing to watch for is the full moon.....the morning ebb and the cycle of the moon are lined up and usually produce good wind during the summer season...so if your gonna come up from So Cal, plan aronnd the full moon....
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