STORM2K

I assume water temperature is one reason why California and other west coast states don't "enjoy" the same hurricane threats we have on the east coast, but what other factors are in play?

Seems Atlantic storms are always basically moving from east to west -- is that a northern hemisphere thing (and therefore keeps storms moving west away from the west coast)?

Thanks,
Mary

Well, water temperatures are a part of it. You also hit something when you talked about storm movement. In the tropics, the wind flow is dominated by the "easterlies". On both sides of the equator, in the tropics, weather systems move from east to west. This also reduces the threat for the West Coast. Finally, there is a lower "cap" on the eastern side of the subtropical ridge (STR) than on the western side. This tends to make conditions on the eastern side of the STR calmer and more stable. (That's why it's hazer in Los Angeles. The "cap" is too low and tends to trap in polution.) This cap also reduces the threat of convection. If you look at a satellite image of the eastern shores of land (on the west side of the STR) you'll see more cumulus-like clouds. If you look at the western shores of land (on the east side of the STR) you'll see more stratus and stratocumulus clouds.

Durning a El nino some systems have been known to get to 30 north...Its between the 120 in the Baja of Califorina that the stratocu is less intense. In which less of a inversion=more unstable air for convection to fire. We seen storms like Emilia make to to 25 north this year as a tropical storm. A good strong hurricane maybe a cat3 or more getting caught by a trough in a El nino years. I would say that southern Califoria could very likely get hit with a cane some day. Near the coast of SD/LA the water temp was 78 degrees at one of the beachs this year.

This cap also reduces the threat of convection.

Unless there's some monsoon moisture.

But yeah, what Mike said, except that in the fall months a stray shortwave can pick up a system and fling its remnants here, but otherwise, the cold California current and stable air from the Eastern Pacific High usually protects us.

SAN has been hit once but if a storm were to hit CA as a hurricane my bet would be on the Imperial Valley since they can either get storms moving up the Sea of Cortés or a Niño season storm crossing from northern Baja. The strongest storm to hit the Imperial Valley was Kathleen in 1976 which brought devastating rains to SE CA and wind gusts to 76 mph to Yuma. In reality, AZ is more likely to get hit than CA and Nora in 1997 was just below hurricane intensity when it swung by Rocky Point with 60kt sustained winds two hours before passing just east of Yuma. Tropical Storm Lester brought 78 mph wind gusts to Sierra Vista in 1992 so we can even see decent TC events here.

Steve

Thanks, all, for your responses. Interesting point about the smog. Increases my appreciation of the clean ocean air we have here. (Which may send hurricanes our way, but at least we don't worry much about fault lines. No five-day cone for an earthquake!)

We got a hurricane right now bombing. In if it fellows the LBAR up the less stable zone between the baja in 120 west. Then you could get something.

I like it when the remnants of East Pacific hurricanes make their way into the U.S. Hurricane Olivia in 1982 helped with the record monthly rainfall here in Salt Lake City. To my knowledge though it's the only tropical cyclone in recent history to significantly affect here. So even if southwestern California and Arizona don't get hit with TCs often, their remnants can still bring some significant rainfall totals.

Didn't a Category 1 hurricane in 1858 brush the extreme southern California coast?

Ah yes, Olivia-that storm made landfall near Santa Barbara as a TD and the heavy rains also caused major (about 600 million dollars) losses to the tomato and raisin crops in CA. Still enough punch in the system to bring 45 mph gusts to the areas around Sacramento. Moisture from Manuel in 1983 produced some major flash flooding around Dugway UT.

Steve

HurricaneBill wrote:Didn't a Category 1 hurricane in 1858 brush the extreme southern California coast?

note, .pdf format

http://www.aoml.noaa.gov/hrd/Landsea/ch ... andsea.pdf