HMT Forecast

As mentioned in yesterday’s forecast discussion… we are essentially dead in the water through at least early next week, with ridge conditions and only an occasional weak, dry vorticity spoke propagating through.

By the middle of next week, there seems to be two preferred operational numerical solutions (depending on the model and initialization time), both hinging on large-scale trough retrogression: (1) cold air spilling across the Intermountain West, with the ridge remaining locked just offshore of the West Coast, and (2) much more vigorous trough retrogression, with the cold air spilling out over the eastern Pacific, and a suggestion of a more zonal fetch developing across CA. The first option would mean the ARB remains dry and becomes a bit colder, whereas the second option could begin to bring at least some precip back into our focus area. It is simply impossible to say what the answer is right now, although for the last decade or so the midtrop atmospheric flow has generally tended toward low-amplitude configurations. If this qualitatively-perceived long-term persistence is maintained, then the second option would be more likely. We shall see. In any event, this situation needs to be followed closely in the coming days.

Paul Neiman