Looking grim up there.
Yep, snowforecast.com combined with NWS forecasts come pretty close to reality. Right now, both are saying that the next wave of storms next week will weaken before they get to us. Earlier this week they were far more optimistic...According to snowforecast.com this will be good for colorado too. Good website BTW.
Bueno!... Significant weather pattern change arrives next week...
High pressure over the western United States will be breaking down
this weekend... bringing an end to the recent dry weather across
eastern Utah and western Colorado by early next week. This will
allow a series of moist Pacific storms to pass over the region
beginning late Monday and continuing through Friday.
As these storms move through... expect widespread snow to develop
over the southern mountains and valleys Monday night... spreading
north by midweek. However... warmer air will eventually filter into
the area... resulting in snow changing over to rain for many of the
lower valleys... especially across southeast Utah and west central
Colorado. By Tuesday afternoon... snow levels are expected to vary
between 6000 and 7000 feet.
Very heavy snowfall will occur over the southern mountains of western
Colorado and eastern Utah as individual disturbances pass through. By
the end of the week... snowfall amounts in excess of 3 feet will be
possible over the highest elevations of southwest Colorado... with
significant accumulations also possible at lower elevations from
Cortez east through Pagosa Springs.
Currently, the strong El Nino is reaching its peak in the Eastern Pacific, and now finally appears to be exerting an influence on our weather. The strong jet has been apparent for quite some time out over the open water, but the persistent block had prevented it from reaching the coast. Now that the block has dissolved completely, a 200+ kt jet is barreling towards us. Multiple large and powerful storm systems are expected to slam into CA from the west and northwest over the coming two weeks, all riding this extremely powerful jet stream directly into the state. The jet will itself provide tremendous dynamic lift, in addition to directing numerous disturbances right at the state and supplying them with an ample oceanic moisture source. The jet will be at quite a low latitude over much of the Pacific, so these storms will be quite cold, at least initially. Very heavy rainfall and strong to potentially very strong winds will impact the lower elevations beginning late Sunday and continuing through at least the following Sunday. This will be the case for the entire state, from (and south of) the Mexican border all the way up to Oregon. Above 3000-4000 feet, precipitation will be all snow, and since temperatures will be unusually cold for a precipitation event of this magnitude, a truly prodigious amount of snowfall is likely to occur in the mountains, possibly measured in the tens of feet in the Sierra after it’s all said and done. But there’s a big and rather threatening caveat to that (discussed below).Individual storm events are going to be hard to time for at least few more days, since this jet is just about as powerful as they come (on this planet, anyway). Between this Sunday and the following Sunday, I expect categorical statewide rainfall totals in excess of 3-4 inches. That is likely to be a huge underestimate for most areas. Much of NorCal is likely to see 5-10 inches in the lowlands, with 10-20 inches in orographically-favored areas. Most of SoCal will see 3-6 inches at low er elevations, with perhaps triple that amount in favored areas.
This is where things get even more interesting, though. The models are virtually unanimous in “reloading” the powerful jet stream and forming an additional persistent kink 2000-3000 miles to our southwest after next Sunday. This is a truly ominous pattern, because it implies the potential for a strong Pineapple-type connection to develop. Indeed, the 12z GFS now shows copious warm rains falling between days 12 and 16 across the entire state. Normally, such as scenario out beyond day seven would be dubious at best. Since the models are in such truly remarkable agreement, however, and because of the extremely high potential impact of such an event, it’s worth mentioning now. Since there will be a massive volume of freshly-fallen snow (even at relatively low elevations between 3000-5000 feet), even a moderately warm storm event would cause very serious flooding. This situation will have to monitored closely. Even if the tropical connection does not develop, expected rains in the coming 7-10 days will likely be sufficient to cause flooding in and of themselves (even in spite of dry antecedent conditions).
In addition to very heavy precipitation, powerful winds may result from very steep pressure gradients associated with the large and deep low pressure centers expect ed to begin approaching the coast by early next week. Though it’s not clear at the moment just how powerful these winds may be, there is certainly the potential for a widespread damaging wind event at some point, and the high Sierra peaks are likely to see gusts in the 100-200 mph range (since the 200kt jet at 200-300 mb will essentially run directly into the mountains at some point). The details of this will have to be hashed out as the event(s) draw closer.
In short, the next 2-3 weeks (at least) are likely to be more active across California than any other 2-3 week period in recent memory. The potential exists for a dangerous flood scenario to arise at some point du ring this interval, especially with the possibility of a heavy rain-on-snow event during late week 2. In some parts of Southern California, a whole season’s worth of rain could fall over the course of 5-10 days. This is likely to be a rather memorable event. Stay tuned.
Dean, College of Natural Sciences and Mathematics
California State University, Fullerton
Phone: 657-278-2638; FAX: 657-278-5390
Yeah, if the "pineapple express" sets up, the snowfall could be really amazing. I remember a 36 hr storm back in '96 (I think) that dumped 62" at our house. We went from next to no snow on the ground to epic coverage. I recall walking up the snowpile to get onto the roof to shovel it.I hope things materialize the way the forecasts are predicting...yea for the pineapple express - last time I remember that happening we ended up with 36 inches in 48 hours!