Generally, April is a month of rapid drying over much of California....but not this year.
A pattern that brings a series of low-pressure systems to California will be the rule for much of the month.
Let me illustrate by showing you a series of upper-level (500 hPa pressure, about 18,000 ft) maps. Blue colors indicate much lower than normal heights/pressures.
Thursday evening, a strong low center will be parked off California, bringing a moisture flow into central and southern California
Saturday will bring a stronger low to Northern California.
Over the next ten days, substantial precipitation is expected over California and southern Oregon (see below), locations where the snowfall has been below normal. This precipitation will top off reservoirs and ensure good river flow this month.
The predicted total snowfall for the same period is substantial, with large amounts in the Sierra Nevada.
One should note that the substantial precipitation this winter has filled California reservoirs, many approaching full (see below). Right now, CA reservoirs are about 120% of normal.
As noted earlier, the snowpack is substantially below normal (see below), savaged by the recent warm/dry period. Thankfully, California has a massive water storage capacity.
The above-normal water storage in reservoirs will buffer the low snowpack, while rain this month will moisten soils going into the dry season. This is important considering the drying effects of the recent warm/dry weather over California.
I have a question about reservoir storage. You have often mentioned that reservoirs are very full. That sounds great. What about communities that rely on river/aquifers for water? Is the low snow pack going to effect summer stream flows for non Seattle folks?
ReplyDeleteAfter a warm winter left Washington’s mountains largely bare this spring, the Washington Department of Ecology issued a statewide emergency drought declaration as projected water supplies are likely to fall far short of the state’s summer demand.
ReplyDeleteThe Washington Department of Ecology automatically declares an emergency when the projected water supply falls below 75% of normal. Even with (almost) full reservoirs the fact that the snowpack is below 75% of normal triggered this announcement but it's probably premature. They are erring on the side of caution just in case we get a very dry late spring and summer as that natural buffer, which is the snowpack, wont replenish the reservoirs as much as normal. The point may be moot if we get enough rain in the late spring and into the summer. However it is worth noting that the snowpack levels above 5500 ft and in the North Cascades are not of concern. They are normal and in some cases above normal. It may look "bare" in low and mid elevations but certainly not up high. This snow will melt later in the summer helping to fill the reservoirs.
DeleteNorth cascades are at 59% so it is a concern. Also Yakima valley does not get water from there. Given the higher temperatures any snow falling is going to melt quickly and the river flow will have to be spilled. Growers require twice the amount of water in the lakes so it would require an extraodinary amount of rain east of the cascades to make up the difference. And, Oregon is truely in a world of hurt. Snow pack is in the teens.
DeleteYou are forgetting something...the rain and snow is not over....and will supply water and fill reservoirs during the next month
Deletehttps://mybellinghamnow.com/news/297792-washington-state-officials-declare-drought-emergency-for-fourth-straight-year/
ReplyDeleteEcology says it declared a statewide drought emergency on April 8, 2026, with snowpack at about 52% to 53% of normal and the state making up to $3 million available in drought response grants. Legislators can appropriate first-come first-served grants from the base drought relief account (e.g., via bills like SHB 1138) by advocating for requesting drought declarations during extreme conditions. Grant money goes to legislators pet projects.
DeleteWeather.com is going for an extremely cool Wednesday a week from now. Accuweather is a little more optimistic, but it looks like Friday is the apex of this little spring roller-coaster. The record low daily maximum on the 15th is 43, Weather.com is showing 47. Let's not get that close, I was done with winter two months before it even started!
ReplyDeleteThe big question is what are we going to do about it ,are we going to tax it and make it all better by everybody spending more money on eliminating global warming
ReplyDeletePost from Salish Sea News: Statewide drought declared due to dismal snowpack
ReplyDeleteAfter a warm winter left Washington’s mountains largely bare this spring, the Washington Department of Ecology issued a statewide emergency drought declaration as projected water supplies are likely to fall far short of the state’s summer demand. This is the fourth year in a row that part or all of Washington will be under a drought declaration, and it is the fourth statewide drought emergency since 2015. (Dept. of Ecology)
What is your take on the predicted super El Nino?
ReplyDelete