I'm liking what I am seeing in the latest model runs, which advertise a major surge of monsoon moisture and precipitation into northern Utah for Friday combined with forcing from a weak surface boundary to force the action. Storminess could persist in some areas into Saturday.
Below is the latest HRRR forecast of surface wind and 1-h accumulated precipitation valid 0000 UTC 6 August (6 PM MDT Friday). Precipitation is mainly near or northwest of a surface boundary (shift in winds from southwesterly to the southeast to northerly or northwesterly near and behind) draped across central Nevada and northern Utah.
Total accumulated precipitation through 0600 UTC 6 August (0000 MDT Saturday) shows the heaviest precipitation, with areas > 1 inch and pockets > 2.5" over Nevada (some of this precipitation falls today and tonight, especially over Nevada), but streaks of precipitation > 0.5" extend across northwest Utah. Strong cells would likely produce more locally.
Although the surface parcel in the sounding above is the "most unstable", meaning it has the highest CAPE, it is possible that some of these storms may be elevated, meaning that they are developing from instabilities above the surface rather than at the ground. Mother Nature will provide the details. And, while it is impossible to predict the precise characteristics and locations of convective storms at these lead times, this is a period where it will be worth monitoring forecasts and being alert to the possibility of severe weather, including heavy rain and flash flood potential.
One possible fly in the ointment beyond the hit and miss nature of convective storms. A look at the forecasts above shows that current forecasts call for the action to be greatest near, north, west, and southwest of Salt Lake. This puts us on the edge of the best action. Let's hope it doesn't shift northward or westward from advertised.
Unrelated topic her: last week there was a letter to the editor in the SL Tribune stating that worrying about the gondola controversy in LCC is a waste of time if the GSL dries up because it will kill the lake effect snow. I know in your book you explained that lake effect is somewhat overemphasized and more nuanced than most realize. What are your thoughts on central wasatch snow effects from a dried up or diminished GSL?
ReplyDeleteThere are two main effects of a diminishes GSL on snow. The first is the loss of lake-effect snow. The second is increased dust production.
DeleteIn the case of the first, lake-effect contributes little to the snowfall on the Wasatch Back. For a period my group examined in the early 2000s, it contributed about 5% of the snowfall (liquid equivalent) in the Cottonwoods. That's not trivial, but the view that it will somehow disrupt the ski industry by itself is overstated.
Long-term climate change is a much bigger threat.