America’s Cup World Series
San Diego

Updated: 12:45PM PST – Sunday November 20, 2011

Current Conditions at 12:45PM: Mostly cloudy.  63F (18C).  Winds on the water off of Broadway pier are now around 12 knots with higher gusts to near 16 knots.  The bridge on the USS Midway is reporting 19 knots from the SSE and San Diego Airport is reporting S at 14 knots.  The WeatherFlow.com sensors at the ocean front are measuring S at 17 knots at Tourmaline, 15 knots from the SSE at Point Loma, 19 knots from the S at Zuniga Jetty, and Silver Strand SSW at 20 knots.

Synopsis at 12:45PM: Large-scale southerly flow has fired up across southern CA in advance of the approaching storm system.  Occasional cloud breaks will only add to the UP and DOWN nature of the winds.  Look for SSE to S winds across the race area to reaching 12-15 knots with higher gusts, but lulls to around 8 knots with thicker clouds.  Light rain looms offshore, though, and any rain showers that develop will make winds more UP and DOWN in nature and any enduring rain showers will make winds plummet in strength.  However, the heavy rain bands still remain well off and shouldn’t arrive until well past 3PM.

Weather: Mostly cloudy with some sprinkles possible between 1PM and 3PM.  Heavier rain showers building in, probably after 3PM.  Temperatures reaching low 60’s F.

Detailed Wind Forecast for Today (11/20/2011):

Hedge:
1) Expecting rain showers to hold off until at least 3PM, however, if rain bands push in more quickly in the afternoon, winds will shift more southwesterly sooner AND remain 2-3 knots lighter than the tables.

2) The SSE to SSW nature of the winds will keep much of the race course in a wind shadow from North Island.  This should favor the eastern third of the course, especially south of the starting line, and the waters just off Harbor Island for the stronger winds. (SEE IMAGE BELOW)

3) Winds very UP and DOWN in nature.  Large variation with lulls to 6 knots and gusts possibly to 15 knots at times.

Forecast Discussion from 7AM: The story for the day is the approaching storm system.  It is currently centered about 120 miles west of San Francisco.  The main band of clouds and rain showers has already dropped over Point Conception and Santa Barbara is seeing rain showers build in already.  For San Diego, the marine layer will keep early morning skies cloudy with isolated drizzle possible, mostly across higher elevations.  As the morning progresses, the marine stratus clouds should break up enough to allow for blue sky to poke through.  We reach midday we should see partly sunny to mostly cloudy skies with modest SSE to S winds building.  By the mid-afternoon, though, the band of clouds and showers nears.  The winds become a bit brisker, but also gustier.  SSE to SSW winds reaching averages to 10 knots at times but unsettled in nature with occasional higher gusts possible.  Pretty much all the computer models have consensus that the rain showers arrive between 3-5PM, but given the storm system’s track so far the arrival of the rain showers looks to be more around 3PM than 5PM.  Even so, this system could drop more quickly toward southern CA and rain showers should arrive as early as 1PM thereby weakening the winds throughout the race period.

Tides: San Diego Bay

11:33 AM PST      1.08 ft  Low Tide

5:22 PM PST         4.33 ft  High Tide

Outlook for Tomorrow (11/21/2011):

Extended Outlook: The storm system slowly exits with early morning sprinkles still possible, but the clouds gradually break up and mild clearing WNW to NW winds fill in.  With interior temperatures so cool and the NW winds across the southern CA bight still pretty modest, the winds that reach San Diego Bay will remain pretty mild as well, probably reaching 5-8 knots.

Forecast Team: Mike Godsey, Benjamin Miller, Jeff Quick