|May 16, 2015. A reminder that late-spring storms are part of the Wasatch climatology.|
However, forecasts change and that trough is now expected to amplify later and moves into the western U.S. as an open wave accompanied by a strong cold front that is expected to push through northern Utah late Tuesday night and early Wednesday morning.
Ooooh, the lower right hand panel of that GFS forecast is a beauty!
The forecast, however, is no slam dunk because this is a case where the trough is amplifying and closing off over the western US, as evident a bit later in the forecast cycle.
That closing off process tends to be somewhat chaotic, and that in turn leads to uncertainty regarding the position of low, accompanying precipitation bands, and the characteristics of the flow impinging on the Wasatch Range.
Thus, we'll take a look at the downscaled forecasts from the short-range ensemble forecast system. Some members produce some precipitation this evening, tonight, and tomorrow in advance of the trough. Others are dry for that period. Perhaps we'll see some scattered mountain rain and snow showers with a clap or two of thunder. That would be nice, but the potential for real snow is really Tuesday night and early Wednesday with the frontal passage. Temperatures during that period will also be dropping like a rock. Most members are enthused about the frontal passage and produce anywhere from about 0.6 to a bit more than an inch of water.