On Thursday (8/18) Northern CA surf was thigh high or less. South facing breaks were head high to 1 ft overhead. Central California surf was chest high. Southern CA breaks from Santa Barbara to just north of LA were waist high to chest high at the best breaks. The LA area southward into Orange County was head high with sets to 2 ft overhead. Southward to San Diego waves were waist high. The North Shore of Oahu was nearly flat. The South Shore was waist high. The East Shore was 2 ft.
Decent south swell, the first in weeks, continues to hit California but has maxed out with a downward trend expected. A much smaller one is behind it but only for breaks with direct south exposure. The models suggest a real storm pushing under New Zealand a week out but odds of that actually happening are very low. Otherwise a generally calm pattern expected down south and in the north, though some north windswell for California is likely mid-next week. See details below...
SHORT- TERM FORECAST
Current marine weather and wave analysis.cgius forecast conditions for the next 72 hours
At the jetstream level on Thursday (8/16) thing were looking about as expected, with a trough in the Northern Gulf of Alaska with 140 kts winds present and a second much weaker one digging deeper over the dateline. The Gulf trough looks to have some ability to reach down to the surface (animation here). Over the next 72 hours the Gulf trough is to track east and drop further south but loose energy while a big ridge builds over the West Pacific tracking through the Bering Sea. A cutoff upper low is to form under the ridge at the dateline just meandering there. Nothing much expected at the surface.
At the surface today high pressure at 1024 mbs was off California and almost north of Hawaii generally filling the Northeast Pacific. A 1004 mb low in the northern Gulf of Alaska was generating some 25 kt west winds aimed at the Pacific Northwest with no real swell generation potential. A broad but weak low at 1004 mbs was over the dateline and not generating any swell producing fetch (animation here). Over the next 72 hours the pattern is to moderate some, with the Gulf low and the dateline lows fading out, high pressure moving northwest of the Hawaiian Islands and a new weak 1012 mb low forming northeast of the Islands. Some 20-25 kt north winds to develop off the backside of this small low aimed at Hawaii, providing just the faintest windswell generation potential for north facing shores. But generally a weak pattern.
More model data here
No tropical systems present.
California Offshore Forecast
Thursday mornings local charts (8/18) indicate that high pressure has tracked to the west, currently positioned north of Hawaii at 1024 mbs. No north winds were indicated off Cape Mendocino, the normal source for California's summer northerly windswell. Low pressure forecast north of Hawaii is to continue suppressing high pressure off the coast through the weekend. But by Monday (8/22) a new high is to build just off the coast with gradient north winds starting first off Pt Conception then building northward into late Tuesday (8/23) when 35 kt north winds are forecast off the Cape through Wednesday (8/24) then fading slowly. The GFS model suggests a large hurricane south of Southern CA at about the same time, but that outcome is not likely. So north windswell early to mid-next week is the mostly likely local swell source.
The 5 Day wind forecast is now included with the surf & swell overview in the QuikCAST's.
On Thursday (8/18) the jetstream charts continue indicating a fully .cgiit jet tracking across the Pacific, with both the north and southern branches reasonably well separated and tracking due east parallel with each other. A new ridge was developing in the southern branch pushing over the western edge of the Ross Ice Shelf and a much stronger ridge tracking east over the Southeastern Pacific. Only a minor gap existed between the two and it was highly unlikely much could form a the surface in that small space (animation here). Over the next 72 hours no real change forecast with a moderate ridge in the southwest and a bigger on in the southeast. No support for surface storm development suggested.
At the surface today strong high pressure at 1032 mbs remained over the Southeast Pacific totally locking it down. A 988 mb low was well east of New Zealand starting to interact with the high generating a 40-45 kts fetch, but it was all pointing due south towards Antarctica, pushing swell in exactly the opposite direction required to generate surf for Hawaii or the US West coast (animation here). Over the next 72 hours a tiny 968 mb low is forecast to develop southeast of New Zealand tracking east and producing a tiny fetch of 50-55 kt winds on Friday (8/19) then fading quickly. No real swell expected to result other than some background swell for Hawaii. Another equally small low to develop just southeast of Tahiti on Sunday (8/21) but neither is to have enough staying power to generate decent seas.
More model data here
2nd SE Pacific Storm
Utility class swell already hitting the CA coast to be fading with period in the 14-15 secs range on Thursday and dropping out by Friday (8/19).
Southeast Pacific Storm
On Friday (8/12) a minor dent in the southern branch of the jet stream aloft allowed some activity at the surface. A 948 mb storm developed well east of the Southern CA swell window over Antarctic Ice with some fragmented areas of 40-45 kts west winds north of the iceshelf near 58S. They blew from Friday AM through Sunday morning (8/14) with seas modeled at 32 ft late Friday and again late Saturday on the very edge of the Southern CA swell window and 5280 nmiles away. But the winds and seas were tracking fast to the east aimed 70+ degree east of any great circle path to Southern CA. Maybe some hope for small utility swell focused on Southern CA starting mid-day Sunday (8/21) through Wednesday (8/24), but sizes that large are probably wishful thinking. Expect 2.0-2.5 ft @ 15-16 secs (3.0-3.5 ft faces) only at the most exposed south facing Southern CA breaks. Swell Direction 180 degrees.
Marine weather and forecast conditions 3-10 days into the future
Thursdays upper level models (8/18) indicate that beyond 72 hours the ridge that was in the West Pacific is to expand eastward blowing over the Aleutians with the only vestiges of the trough in the Gulf to be a weak upper cut-off low circulating off North California (Tuesday 8/23). This pattern to hold through late in the workweek. As a result a rather calm pattern expected at the surface.
Beyond 72 hours at the surface weak high pressure is to generally take over the North Pacific centered just east of the dateline ridging well east and west. The biggest feature is to be a large developing hurricane tracking northwest off Baja early next week well into the California swell window. The GFS model is notoriously bad a predicting tropical systems, but it makes for nice eye candy. A bit of north winds at 20-25 kts if forecast of Cape Mendocino CA too providing some minor windswell generation potential for North CA. Less than usual trades to continue over the Hawaiian Islands.
On Tuesday (7/27) the Southern Oscillation Index (SOI) dropped to -14 and has held in that range steadily through Thursday 8/4 with a -16 value posted. Then it gave up ground with values bouncing from near 0 to -16 with the 30 day average hovering near -7 through today (Thursday 8/18). A negative SOI is conducive to the development of El Nino and prolonged negative readings (2 weeks.cgius) is evidence that the active phase of the Madden Julian Oscillation (MJO) was occurring. A reversal of tradewinds over the Pacific equator typically accompanies such events. The first signs of such a breakdown developed west of the dateline starting Thursday (8/4). By Saturday (8/6) west wind were clearly evidenced to 160E and building eastward reaching 170E by Tuesday (8/9) then holding. But on Sunday (8/14) the trades dropped to near neutral and were returning to normal today (blowing from east to west). Subsurface waters temperatures were 1 degree above normal in the West Pacific pushing towards the dateline, suggesting a minor Kelvin wave was trying to organize. But it was impacting a pool of -3 degree cooler than normal water southeast of Hawaii. That pool is now moderating to -1 degree while the mini-Kelvin wave continue east at 1 degree above normal. Forecast models suggest this Active Phase of the MJO is over, with the inactive (cool phase) of the MJO weakly in control. But that is to fade quickly by 8/23. Though it is too late in the year for a full blown El Nino to start forming, a series of active MJO's can help to improve the chances for winter season storms and are a catalyst for development of strong tropical systems in the West Pacific (look for them to turn extratropical and curve northeast in the fall). This minor bout of the MJO appears to have influenced the North Pacific jetstream and improved the potential for early season low pressure development in the Gulf of Alaska. Unfortunately that has come to an end.
Thursdays upper level models (8/18) indicate that beyond 72 hours a strong ridge is to remain over the core of the South Pacific but a weakening of the flow expected in the east. No support for surface storm development suggested though. And in the west under New Zealand the jet is to really start moving, to 170 kts (on Wednesday (8/24) and positioned just far enough north that maybe something could form under it, but odds are low.
At the surface beyond 72 hours out the models suggest a 948 mb storm is to develop south of New Zealand on Wednesday (8/24) tracking east. 40-45 kt east winds covering a large area and 39 ft seas are expected through the end of the workweek aimed generally to the northeast. This could produce solid swell for Hawaii and the US west coast, but given how far out in to the future this is, the odds are non-existent of it actually occurring. No other swell source suggested.
Details to follow...
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Tutorial on the Madden Julian Oscillation (MJO) Presented by Dr. Roland Madden: If you're interested in El Nino and the MJO, have a basic understanding of El Nino, and you have broadband connection, audio and Macromedia Flash installed, then the following presentation is a must see. Dr Madden present a great overview of how the MJO works. And there's nothing like hearing it straight from the founders mouth. Link here: http://meted.ucar.edu/climate/mjo/mjonav0.htm
Stormsurf Weather Models Updated Again: Yes, we've been at it again this weekend getting another batch of weather models running. Global coverage is now provided for jetstream forecasts and surface pressure and winds. Zoomed in data is also available for such locations as the Mentawai Islands to Western Australia corridor, Tahiti, South America, Europe and Norwegian Sea. So now you can get local wind forecasts for these and more locations with one click. Take a look here: http://www.stormsurf.com/mdls/menu.html
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Surf Height-Swell Height Correlation Table