“Heads Up” Dynamic time of year for our weather and water supplies — Nolan Doesken

Nolan Doesken -- Colorado Water Foundation for Water Education President's Award Presentation 2011
Nolan Doesken — Colorado Water Foundation for Water Education President’s Award Presentation 2011

From email from Nolan Doesken:

I just wanted to give you a quick climate update.

We’ve had a fairly average winter so far in terms of precipitation and mountain snowpack accumulation throughout much of the Upper Colorado River Basin and the remainder of Colorado. But after the first few days of February, the frequency and intensity of storms has declined, winds have increased, accumulation of mountain snowpack has leveled off in many areas and we’ve seen a marked warm up in temperatures with a loss of low elevation snow (welcomed by those of you who live and work in some of the mountain valleys that “enjoyed” a frigid winter thanks to localized cold-air pooling.) This is not totally abnormal, but a bit troubling.

We’re now in the final and often most important months of the winter in terms of water supply. Forecasters are back pedaling on their earlier predictions for wet weather this coming 1-2 weeks. The storms are still anticipated to bring copious moisture to northern and central California but now seem more likely to dissipate as they move into the Central Rockies. But long range seasonal predictions (see the 3-month March-May precipitation outlook http://www.cpc.ncep.noaa.gov/) are sticking
with the forecast of a good chance for a wet and fairly cool spring — even though the El Nino Southern Oscillation appears to be weakening now (consistent with previous forecasts). Cool wet springs, when they occur, are always a boon for water supplies and sometimes an indicator of flood potential.

If you’ll recall, last year we were very dry and quite warm in March and early April and were losing hope that the anticipated wet spring would material. But it did show up in dramatic fashion. The current forecast is somewhat similar to what was issued for this same time period last year — driven, again, by El Nino relationships — but will likely not play out in the same fashion. Every year is different.

Looking beyond spring, it is very difficult to anticipate summer precipitation anomalies. But most forecasts lean towards anticipating a hot summer — a reliable trend in recent years.

Meanwhile, California’s wet season only has a few more weeks to go, so this week’s anticipated storm is a big deal there. Here in the Rockies our spring “wet seeason” is much longer — lasting to early June on the Front Range and eastern plains. So we’ll have more opportunities, hopefully..

I’m probably not telling you anything you don’t already know, but just want to make sure we’re all paying attention at this critical time in the water year. As we’ve seen time after time — with particularly dramatic drying in spring 2012 and wetting in spring 2015, these next few weeks can make a huge difference.

We will continue to do our detailed weekly assessments and will send e-mail updates each week on Tuesday evening with links to updated climate and water information http://climate.colostate.edu/~drought/

We will also be on “high alert” with an approx 2-week cycle for Tuesday morning 10 AM webinars where you can watch, listen in and chime in.

Local expert participation is greatly appreciated. The next webinar will be March 15th: http://ccc.atmos.colostate.edu/drought_webinar_registration.php

We are aware that we may be trying to cover too much information in too much detail, so we’re working to streamline these briefings and leave more time for feedback and local input.

If you know of others who would like to be on our distribution list, please let me know. Likewise, if you are tired of getting all this climate information every week just unsubscribe. Finally, I appreciate your input and suggestions on how to improve our information delivery.

We notice that 40% or more of our mailing list do open our weekly update messages — so I guess that’s good.

OK, one LAST thing. Precipitation varies dramatically over short distances in nearly every storm. If you’re not already, please consider joining the Community Collaborative Rain, Hail and Snow network (CoCoRaHS) and help monitor precipitation from your own back yard. Take a look at the CoCoRaHS maps http://www.cocorahs.org (click on your state and county) and you’ll quickly see what I mean. Experience has shown time after time that one station every square mile is great, and more than that can be even better. Sign up and help out. Don’t worry, you don’t have to be home to measure every day. That’s the power of having lots of volunteers. Report when you can, and don’t worry about it when you can’t. If you know of others — especially folks that live in some of our data gaps — please encourage them to join. Click the “Join CoCoRaHS” button on the website.

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