Today (Saturday) was a great victory for my profession, but also an indicator that we still have work to do. Forecasts for what the Weather Channel named "Winter Storm Nemo" in the northeast United States were outstanding. Five states had locations with at least 30" of snow, and Hamden, Connecticut received 40".
In contrast, our forecast for the central Wasatch was a total bust last night and today. Only an inch fell at Alta-Collins during the 24-hour period ending at 6 PM. While I thought this was a tough storm to forecast, and that there was a wide range of possibilities, an inch was well below my worst case scenario.
At least the snow that fell Friday afternoon provided some fun dust on stuff conditions in the Wasatch backcountry. We found pretty good conditions at upper elevations facing due north where several inches of snow fell on a soft crust that didn't seem to inhibit fun turns. Everywhere else there were a few inches of snow sitting on a variety of crusts, but it skied surprisingly well. I was skiing with a fellow meteorologist and we found that the conditions helped soothe our wounds.
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| The name of this meteorologist has been withheld for protection |
Great blog, by the way. Just found it and have read a few posts back.
ReplyDeleteI've been watching and skiing/hiking in SLC/Wasatch weather since 1956 (well - maybe 1964 as I was born in 1956).
The inaccurate forecatsing of a big snow event this past weekend did not surprise me - I told my wife on Friday that the storm had crapped out when she asked why I was driving to Moab Saturday morning.
I have the following observations about snow forecasts for SLC/Wasatch:
1. There is no science to SLC/Wasatch weather forecasting. The probability of accuracy has never been good and has never improved.
2. The bigger the forecast event and the further out the forecast the less likely it will occur. The formula is number of forecast feet at Alta times the number of days out. A two foot storm predicted 2 days out has a 4 to 1 chance of NOT occuring (2X2).
3. The LA Effect: Unless it rains in LA the chances of more than one inch of SWE precipitation at Alta is less than 50%. If it rains in LA the chances are greater than 50%. This is true.
4. The Great Basin missing storm effect: Meteorologists predict storms in SLC/Wasatch based on what they look like hitting the coast and what their models say they will do. What they do not do is track their progress and strength as they cross the Great Basin, Southern Oregon or the Mojave Desert. I can watch the weather in Las Vegas, Ely, Werndover and Boise or Twin Falls, watch the radar, watch the western horizon and tell you when a storm has completely crapped out. The meteoroligists - a la last weekend - will continue to insist that a storm will materialize out of thin air just because their models say so.
Last Friday I told my wife that the weekend's big predicted event had crapped out. I drove to Moab Saturday morning in perfect sunshine the whole way. A bit of snow Saturday night, but nothing like the forecast. If there ain't no marine moisture in the system it aint gonna snow. Low pressure systems forming over Utah do not "suck" moisture into them from nowhere. They need a train of moisture from the coast and it needs to have actually precipitated in Wendover, Ely, Boise or Las Vegas (not all of them - but at least one of them).
Meteoroligists insist that their models are more important than emperical observation. The storms are like Civil War armies marching across hundreds of miles of terrain. Often they get lost, go the wrong way or arrive completely worn out. They might have been ambushed along the way and wiped out. The key is watching them after they cross the Sierras, the Cascades or enter the Mojave.
That's why the LA efeffct is so important. A storm can make it to SLC from the deep southwest without crossing a major mountain range. Anything from due west (Sierras) or the northwest (Cascades)or even WSW (Sierras plus Eastern Nevada mountains plus Stansburies/Oquirrhs) has to cross mountains and ususally loses 3/4 to 9/10ths of its marine moisture.
It seems high time that Wasatch meteoroligists began to apply the scientific method to their work - meaning - review past forecasting for accuracy and correlating failure to real-world causes.