Cold troughs; the GFS is a liar…

Well, after what had looked originally like a promising late-season cold and convective event this weekend, the scenario has trended towards colder, drier, and windy weather for the weekend and into next week. An unseasonbly deep trough and associated low will bring showers and isolated thunderstorms with very low snow levels to all of WA and OR and possibly far N. CA near the Oregon border, but no further south than that. NorCal will be left with much colder air aloft–strong gradient-derived winds on Saturday (above 40 mph in some places  and afternoon highs 55-60. Overnight lows will drop below 40, possibly leading to some frost in sensitive locations in the Central Valley). The models now try to undecut this trough with a Pacific jet by next Tuesday, bringing a weakish low into NorCal on that day with some scattered showers (and, as with essentially any system this time of year, possibly isolated thunder). The GFS has had an impressively bad track record as of late, though, so I will remain extremely skeptical until I actually feel some raindrops before buying into that prognostication. In any case, significant rainfall is not expected anywhere in the state for the forseeable future, and likely for the rest of the season.  It’s important to remember that rainfall in SoCal sometimes does cut off after February (though there is usually at least a couple of shower events). NorCal, on the other hand, tends to see precipitation through April and sometimes May on the average year.  Up here, I haven’t felt a raindrop (except for a literal 5 minute light shower on the immediate coast 1 month ago which apparently didn’t make it inland) since early February. That’s concerning. The wildfire season has already begun in NorCal, and although the snowpack is not too far below average at this point, it’s melting quite quickly. I’m curious to see what occurs with the ENSO over the next 12 months–we’re due for a major El Nino event at some point in the next few seasons. As I’ve mentioned before, the next big El Nino event will almost certainly bring the highest global temps ever recorded–and I’m curious what effect that may have on atmospheric river (Pineapple Express-type) events in CA.  Only time will tell, I suppose. It’s going to be a long and dry summer, in any case…