Our extremely dry Spring 2008 continues. NorCal did see some very light precip last week in areas, but it was significantly less than expected (suprise) and some locations up here (Davis, for example) have yet to see even 0.01 in. since February. This has not happened in decades…and at a few reporting stations this is the only time in history this period has been entirely rain-free. There is currently no rain in the offing for the next two weeks, which brings us to mid-May. I really don’t think there’s much hope for more precip for the rest of the “season,” even in NorCal. We could see an odd cutoff or two bring some scattered convective precip at some point if we’re lucky, but there is currently no indication even of this. SoCal has already seen 100 degree plus readings and wildfires have caused evacuations over the past week, so the summer season has effectively started down there already. I do believe that we will see som significant spring heat waves in May that will expand to include more of NorCal that the 90-95 degree Valley heat on Sunday. With the apparent demise of La Nina (having decreased to marginal La Nina strength) and the possible emergence of an El Nino over the next 6 months, I think this summer has the potential to be quite hot and potentially active (reminiscent of summer 2006). The Sonoran heat ridge will likely feature prominently (especially by the second half of summer), which would bring prolonged southeasterly flow and a cT airmass up from interior Mexico. This translates to very hot temperatures and the potential for periods of enhanced monsoonal convection. Obviously, predictions for summer temperature and monsoonal flow are not very skillful this far out, but given the comparison to analogue years, I do think this is a reasonable possibility. Stay tuned.
