Tuesday, January 19, 2010

New Storm Warning from NASA

Hi Friends,
Ok, maybe the photo is a little dramatic, but we are about to be hit with a big one according to my pals at NASA. Normally I wouldn't post a blog like this, but considering the content, you may understand why I am making this exception. I just got an email from a friend who works with these folks and kids, this is the real deal. They are saying most of us who live in these mountains have never see or experienced the likes of the storm that is coming our way.


Stay safe and warm. My thoughts are with you all!


I am forwarding a weather forecast from NASA regarding storms
projected to hit California and the Sierras. The NASA forecast appears
much more severe than the weather updates received from your office.
Although your information is focused on our region, I thought you
might want to take a look at this.
Edward D Atwell
Emergency Management Coordinator
University of Nevada, Reno
Police Services
1664 North Virginia St. M/S 0250
Reno, Nevada 89557-0250
(775) 682-7247
"Community First"

Get ready. This is what the emergency response community is saying:

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 lower 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
during 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.

Alexandra Pitts, Assistant Regional Director External Affairs
Pacific Southwest Region
(w) 916 414 6619
(c) 916 804 4967

1 comment:

  1. wow. why is everything suddenly happening in Epic Proportions???