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DWR weather & climate news: Rain yes, snow no, and still in a drought, 2nd lowest initial allocation; climate change in California & more

Posted by: Aqua Blog Maven on October 31, 2008 at 5:58 am

From the Department of Water Resources, it’s weather and climate news!

Yes, it will rain on and off the next few days. No, we won’t pull out of the drought.

First off, the weather situation is clouding over. Literally, not figuratively. A long jet stream stretched well across the Pacific taps tropical moisture through the weekend, by way of an offshore deep trof off the west coast. It won’t rain the whole time, and hopefully there’ll be a break timed for Trick or Treat. But expect wet weather for the northern and central parts of the Golden State in the days ahead.

Timing and amounts:
This afternoon and tonight, rain showers will occur over the northern half of the state, under a southerly flow. Tonight/ Friday’s wave tapers in the late afternoon/ early evening in the valley and coast, but still could be a little soggy for foothill locations on Halloween night. Of the 2 or 3 waves, the Saturday/Saturday night system will be the heaviest. South / southwesterly winds will enhance orographic forcing (more lift, more rain) on south facing slopes. These are warm RAIN systems, with snow levels quite high; 7,500′ to 11,000′, across the state, generally speaking. Total northern Sierra (and some north coastal) precip totals will climb to 5-6″ through the weekend. By Sunday morning, the system spreads rain along the central coast, as far south as about Santa Barbara. Big Sur burn areas may see a total of 2-3″ of rainfall by the end of this weekend. (More on burn areas in a moment).

This set up does have some tropical moisture in it, and has connections that suggest the onset of what would be a welcome wet pattern. No one wants it to go overboard, but perhaps the MJO, Madden-Julian Oscillation, will produce many of these types of storms in the months ahead. Of course, that’s not a forecast, it’s a wish. Without a strong La Nina or El Nino in place over the tropical Pacific (what’s known colloquially as La Nada), warm, moist storms have a better chance of making it to the west coast this winter. When combined with a cool Pacific Decadal phase (cool temperatures in the Northern Pacific), there are some scientific reasons to be optimistic about the winter. Nonetheless, these patterns can break down, or modify. So the most we can say is that maybe we’ll make a good start to the fall. Additionally, kudos to the forecast brains of the National Weather Service for calling this pattern ahead of time, for a November shift to wet.

Burn Area concerns: Debris flow related flood problems will be a concern throughout the winter, especially if the storms are of this warm, moisture-laden variety. Heavy rain in a short period of time could create problems over the multitude of areas impacted by record wildfires this past summer. 1.16 million acres were burned this year, not just in Southern California, but Northern, too. For a look at the burn areas (and consider those now higher flood risk areas), please go to:

http://www.fire.ca.gov/downloads/incidents/All_statewide_Fires_0622_081108_a.pdf

If the link above does not come through the server due to its length, please go to the CalFire home page, click on fire information, then incident maps on the right, scroll down to Fire Links 2008 Lightning Siege overview, then scroll down to 2008 Lightning Siege Incidents Maps and Links, then click on Cumulative Fire Map. Wow, that shouldn’t have been so hard to locate. But it’s worth the search to see this great map.

Thresholds for critical rain amounts will vary for each location, depending on vegetation, intensity of the burn, soil type, terrain, etc. The United States Geological Survey and the National Weather Service have some great products and programs available to them, after several years of concentrated effort. Emergency managers will be able to count on specific burn area flash flood guidance from the NWS across the State.

As for current water supply, the situation remains poor. Dismal should be reserved for year’s end, if we don’t get rain. Statewide storage amounts are the lowest they’ve been in 14 years. Currently, our reservoirs are holding 15.84 million acre feet (MAF) of water. The last time they were this low was in Sept., 1994 at 15.76 MAF. What about the Colorado River? It supplies about 50% of the water used in Southern California. It’s reservoirs are currently at about 57% of capacity.

DWR’s new reservoir graphic is now available on line. This is a great improvement, with comparative size of the reservoirs, as well as %’s of capacity, and average. This will be updated monthly, with 1st of month data posted approximately on the 8th business day:

http://www.water.ca.gov/drought/docs/102008current_conditions.pdf

The Department of Water Resources today announced an initial allocation of 15 percent for water delivery to the State Water Project (SWP) contractors in 2009. The allocation is the second lowest initial allocation in the history of the SWP. It reflects the low carryover storage levels in the state’s major reservoirs, ongoing drought conditions and court ordered restrictions on water deliveries from the Delta.

The lowest initial allocation figure was 10 percent of SWP Contractors’ requests in 1993, but that number was increased to 100 percent during the water year as conditions developed. Last year, the initial figure was 25 percent and it was increased to 35 percent as the year progressed.

CLIMATE CHANGE in California: DWR Document release, and Adaptation Summit.
On Wednesday, October 29, 2008, DWR released “Managing an Uncertain Future, Climate Change Adaptation Strategies for California’s Water.” To read the 34 page document, please go to:

http://www.water.ca.gov/climatechange/docs/ClimateChangeWhitePaper.pdf

This document summarizes what’s been seen in California in terms of climate change. Disturbing trends over the last half century suggest California faces a shrinking snowmelt, increased flooding, longer droughts and a rise in sea level. The report strongly suggests that statewide water management systems adapt as the climate changes. Strategies include coordination of land use, watersheds, reservoirs, floodplains and aquifers to protect public safety, preserve water quality and supply and provide for the ecosystem. California must expand research of climate change and its impact on water and the environment as well.

To that end, DWR and the Water Education Foundation are hosting a Climate Change Adaptation Summit in Long Beach on November 13 and 14.

http://www.watereducation.org/doc.asp?id=852&parentID=849

A number of very good topics and speakers will be included in this day and a half conference.

Welcome new subscribers! Readership is approaching 1,500. The 1500th signer-upper will receive some sort of prize. Of course I won’t say how close we are because that would give an advantage. (No one with moderator list approval can cheat, look, or win!) This will not be a financial prize, just major statewide celebrity (ha!). Perhaps we can throw in a tour of the Flood Center, or a visit to a Snow survey, or some such experience. A CoCoRaHS T-shirt is likely, and perhaps a bit of DWR paraphernalia. I will check with the 1500th person to be sure they are okay with my sending a shout out. Bill Mork wrote this newsletter for years. When I took it back up about 2 years following his retirement, so many email addresses had been discontinued that the list dropped to 1116. So, happy to see membership expanding. As a former TV meteorologist, I’m aware that weathercasts on the telly don’t provide the detail or perspective most water users are interested in. Thanks for your support of the letter. Here is the self serve sign up link:

http://listhost2.water.ca.gov/mailman/listinfo/weather_and_climate_news

DWR/Flood Management announces an Associate Meteorologist job opening. This position will be in Sacramento. A Bachelor’s and 3 years experience, or a Master’s and 2 years experience is required. Here is the link for all information. All inquiries should be made via the DWR personnel contact information in the exam announcement:

http://www.water.ca.gov/jobs/pdf/8WR65.pdf

Final filing date is November 24, 2008. Applicants must meet the qualifications, and then take a test. Please feel free to send this job announcement to anyone who might be interested, or could share the announcement with potential candidates.

Monthly hydrometeorological and climatological summaries are available on the State Meteorologist and State Climatologist home pages:

http://www.water.ca.gov/floodmgmt/hafoo/hb/csm/
http://www.water.ca.gov/floodmgmt/hafoo/csc/

Be back within a couple weeks, and perhaps the contest winner’s name!

Please don’t reply to this list with queries. Contact: Elissa Lynn, elynn@water.ca.gov

HAPPY HALLOWEEN ! !

October 31, 2008 · Filed Under Drought, Weather & Snowpack

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