Hot and dry CA

I apologize for the lack of updates lately–quite frankly, the weather in California has been seriously monotonous. Much above normal temperatures and low moisture levels continue to plague CA, especially the northern 2/3 of the state. Even San Francisco proper hit 93 this afternoon, and most inland locales were in the triple digits. Weak offshore flow and warm 850 mb temperatures will continue to bring hot and dry weather to CA, with some minor interruptions, for the foreseeable future.

In the most recent GFS model runs, a fairly noteworthy scenario has begun to pop up in the 6-10 day period. A decaying tropical storm is currently depicted by the GFS as riding up the  Baja coast with a weak cutoff low off the coast of CA. The remnants of this former cyclone then bring copious moisture into the state from the south and southwest, bringing a good chance of showers and thunderstorms. This scenario is actually very plausible, and should be watched very closely, especially given that the event would begin in less than a week. Stay tuned in the coming days–this could also produce a major fire weather threat as fuels are explosively dry up here after the dry winters and a hot and extremely dry summer.

Hurricane Gustav, which made landfall in Louisiana as a category 2 storm earlier this week, did not cause as much damage as it might have. The most obvious reason was that the storm was not nearly as strong as it could have been at landfall. Remember: wind damage and storm surge increase exponentially,  so the difference between 105 and 135 or 145 mph winds is actually quite large. The storm also hit a bit west of our worst case fears, and although there was significant damage to the region (and 1 million people have yet to return to the area), New Orleans and the Gulf Coast in general really lucked out on this one. My only concern is that the “unnecessary” evacuation of New Orleans and surrounding parishes will dissuade people around the country from taking future evacuation recommendations seriously enough.

As it turns out, a major test of people’s continued willingness to mass-evacuate may occur much sooner than hoped for. Hurricane Ike, which intensified rapidly over the central Atlantic Ocean 36 hours ago into a monster category 4 storm, is currently headed westward across the ocean. After a SWward dive in 24 hours and perhaps a diminishment of winds to category 2 or 3 status as the storm passes through a region of higher uper-level wind shear and in the “cold wake” left by Hannah, the storm is expected to curve back to the north in time to roar across the Bahamas as a re-intensifying category 3 or 4 hurricane. Given the very high thermal potential energy of the water off the eastern coast of Florida currently, the forecast track for Ike is extremely concering. The NHC and a surprising consensus of models are currently indicating a landfall in SE Florida near Miami. Ike will be intensifying at the time of landfall and will already be a major hurricane (probably category 3) as it enters this period of intensification. There is a significant chance that Ike could make landfall in one of the largest U.S. metropolitan areas as a category 3/4/5 storm, with a 4/5 strike actually looking quite possible at this point. It is too early to call for evacuations, but preparations should be made within the next 48 hours as Ike represents a serious threat. Stay tuned to Weather West and Jeff Masters’ Wunderground Blog this week…