2009

Just a quick update this evening. The prevailing pattern has turned much less active than it was for much of April and early May. Seasonably warm temperatures are common in CA, with occasional offshore wind events in favored areas. A large heat ridge will build into CA from the southeast this weekend, bringing hot temperatures (especially for mid-May!). This pattern appears to be very analogous to the heat wave that occurred at exactly this time last year…and some of the records set in 2008 may be the ones threatened this weekend. Temperatures will cool somewhat early next week as some southerly flow and a bit of mid-level moisture gets caught up in the flow aloft. This moisture may bring some elevated humidity to parts of SoCal, and may even be enough to bring at least isolated thunderstorm activity to the mountains. Though this is vaguely reminiscent of a monsoonal pattern, the flow will not be very deep, and probably will not have much impact on sensible weather in most parts of CA. More dramatic cooling will occur towards the end of the week as a deep trough scrapes NorCal, possibly bringing a shower or two to the far north.  More warm to hot weather looks to be the rule after that for the rest of May–which is, I daresay, not all that out of the ordinary.