Hopefully, we will also get some help from Mother Nature over Thanksgiving weekend. For the past few days, the models have been suggesting some storm systems will move through the area during that period, but amounts have been variable. The latest NAEFS ensemble is looking up a bit, however, with all ensemble members producing precipitation at Alta-Collins on Thanksgiving (22 November) and then periods of precipitation through the 24th (Saturday).
That's about the most optimistic forecast I've seen since our early October storm. Let us hope it delivers. Keep up the snow dances and keep an eye on the forecasts the next few days as this is an evolving forecast situation.
How can you tell Alta got an inch? All I see is gibberish, which seems often the case? https://www.wrh.noaa.gov/mesowest/getobext.php?sid=CLN&table=1&banner=off?
ReplyDeleteThat site has two snow measurement sensors. One measures the total snow depth (Snow Depth header in the page you reference), the other the interval depth (Snow Interval).
DeleteThe Snow Depth sensor is typically mounted far above the ground as it needs to be high as the snowpack deepens. The data from it has been quite poor so far this season, which may reflect how high it is. This makes getting a good signal more difficult.
The interval sensor, however, is usually just above a wooden snowboard. When it does snow, it often gives a better signal. You will notice that it reached 1 inch during a period in which the precipitation gauge was also recording precipitation. That is what my 1 inch is based on.
The interval board is typically wiped twice a day (around 4 or 5 pm). Thus, it may reset back to zero or, if it is snowing, a number that is lower than it was previously (reflecting the fact that some snow has accumulated at the observation time immediately following the wipe).
Jim
Thanks for the explanation. I thought maybe when the interval went down it might sometimes be due to settling? Have you done any posts about how the automated weather stations work? I would like to learn more about them.
DeleteSo I am looking at the infrared radar images provided by NOAA and the only moisture I see nearby is moving on the pacific in front of the CA coast. Is this storm forecast from this system?
ReplyDeleteLove your Blog Jim!
Doubtless you will do another post on what is shaping up to be a snowy Thanksgiving weekend. Meantime, the NAEFS plume for Collins has a minimum accum of 20 inches by Sunday.
ReplyDeleteI'll repeat that because I like saying it: minimum forecast is 20 inches accum by Sunday. This is one of the GFS members.
The max is 100 inches, one of the excitable Canadians, which since the President has been denigrating them we Weenies should be respectful and not laugh dismissively at 100 inches. Maybe this Canadian has earnest knowledge that will verify; we can only hope and pray.
The mean of all the ensembles, both GFS and Canadian is 50 inches.
How serious do you take this? Do you think it is 100% certain that we get at least 20 inches, or do the ensembles sometimes completely flub and we end up w dust on rocks? I don't recall a complete flub, but I haven't been keeping track.
We have never verified the Canadian. The day 4-5 24-hour forecast produced by just the 21 GEFS members verifies *outside* the ensemble range 44% of the time. There is a reason why we call this guidance and not a forecast and why one needs to be careful putting numbers on a forecast with 4-5 day lead time. If you want 100% certainty, you've come to the wrong place. On the other hand, I'd be very surprised if we were to end up with a dust on rocks scenario. Both troughs look to produce something, with the amount just dependent on productivity.
DeleteJim