It’s time to reveal the future – or at least its best forecast.
Around next month will probably be wetter and cooler than usual in the Pacific Northwest. Snow and ice will accumulate on the mountain. Our reservoirs will be exhausted. Worries about water supplies in the Northwest and drought will be over, and I think dryland farmers in eastern Washington will be relieved.
We are in the La Nina period, where the central and eastern tropical Pacific Oceans are cooler than usual, and the winters and springs involved tend to be cooler and wetter than usual.
But there’s so much more to it – something I’ve noticed over the years. La Nina conditions tend to lead to large ridges of high pressure in the eastern Pacific, as we have observed frequently over the past months (see example below on Sunday morning). When the mountainside is near us, conditions tend to be cooler and dry, but if it shifts slightly to the West, disturbances can move south, causing showers and snow. That’s happening today, by the way.
Upper elevation (500hPa) (as pressure) last Sunday morning
But in late winter, the northeastern Pacific ridge generally weakens, allowing more rainfall into the Northwest. Thus, rainfall in the Northwest tends to be more frequent in late winter in La Nina and in the following springs.
And nearly all forecasting models will apply to this in about the next month or so. A cool wet early spring.
My favorite long-term forecasting model is run by the European Center, and I’ll show you its long-term (46-day) forecast below (until April 22).
The projected difference in temperature from normal is for colder than normal temperatures across the region. (blue indicates colder than normal temperatures below)
Rainfall in the same period?
Above normal for the mountains of Northwest as well as Southeast Washington (see below).
Great for dryland farmers in southeastern Washington. Their wheat will be important considering what is happening in Ukraine. As in most La Nina years, California will be drier than usual. Not so good.
The Central Europe model predicts heavy snowfall over the Northwest for the next 46 days (see below). I suspect that on April 1, the snow and ice in the area will be above normal. That, along with the reservoirs in the Northwest that are currently very well stocked, bode well for this summer’s water supply.
The predictions of the European Model are in line with those of the others. For example, the US Climate Prediction Center is predicting above-normal rainfall for the rest of the month for our region.
What about short-term forecasts?
We have some light showers from a passing system today, but the real action kicks in this weekend, with heavy rain and snow in the mountains.
Here is the rainfall for the 72 hours ending at 4 a.m. Tuesday. Sorry! Heavy rain (plus 3 inches) from northwestern California to southern BC. Plenty in southeastern Washington.
In short, keep umbrellas and raincoats handy. If you’re a skier, expect an extended season. And if you’re a farmer in eastern Washington, expect a better year than last.
