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Water

Spring moisture and upcoming El Niño weather patterns predicted for the U.S.

Written by Natasha Wheeler

Rawlins – Meteorologist Don Day uses a combination of computer models and analog technology to create long-term weather forecasts. 

He spoke at the Wyoming Agricultural Bankers Conference in Rawlins on May 14.

“Despite the fact that we had a mild and dry winter for many areas in this part of the country, things are looking pretty good as we go into the rest of the summer season,” Day noted.

Summer moisture

Day is optimistic that there are no signs of drought for any of the key agricultural areas in the United States for the upcoming season.

“If we take California out of the equation, we are seeing what I like to call a ‘Goldilocks summer,’” he commented.

Frequent and adequate rain is expected, especially across the Corn Belt of the U.S., which should support high grain yields across the Midwest.

“The whole northern hemisphere is going to have a good summer,” he added. “There is nothing showing the northern hemisphere in big trouble in terms of key growing areas.”

Indicators

One of the major indicators that Day uses for his forecasts is the temperature trend in the Pacific Ocean.

“Warm air holds more water. The capacity for water to be in the air is higher when it’s warmer, and conversely, there is less water vapor in the air when it’s colder,” explained Day.

Therefore, when water in the Pacific Basin is warmer than normal, ambient water vapor increases over all of that area.

“If we think about how the natural winds blow, generally speaking west to east, we are going to be bringing in air that has more water in it when temperatures are warmer than a normal year or when the Pacific is colder,” he continued.

Currently, temperatures in the Pacific are getting warmer, indicating increased precipitation across the U.S. as air moves in from over the ocean.

“The warmer, dryer weather has gone east, and the cooler wet weather has come west,” Day stated of the most recent patterns in the weather.

Recent precipitation

In the 10 days proceeding Day’s presentation, one to five inches of precipitation fell in many areas of Colorado, Wyoming and the Dakotas. Some areas of Texas and Oklahoma received more than nine or 10 inches of rain.

“Some of these areas were those hit hardest by the drought in 2012 and 2013,” commented Day.

Soil moisture content has also been increasing across the West, with noticeable differences since April 30.

“All across the Central Plains, especially in the wheat country of Kansas, Oklahoma, Nebraska and South Dakota, as well as Wyoming, Utah, Colorado, eastern New Mexico and a big area of West Texas, have had a dramatic soil moisture change,” he explained.

More moisture

Although the snowpack has not been very good this year, the three wettest months of the year are typically April, May and June.

“We’ve turned the corner,” Day said. “The money months are coming through, and this moisture trend is going to continue.”

Predictions indicate that another five to nine inches of precipitation can be expected along the Corn Belt in the upcoming month, and Wyoming can expect two to four inches in many areas across the state.

“In some pockets of the Bighorns and up in the Yellowstone Plateau, we are talking about getting six to seven inches of precipitation,” Day noted.

Even areas of northern and central California are expected to receive rainfall in the upcoming weeks.

“Everything that we are seeing is indicating a continuation of this wet trend we’ve had over the last four weeks,” he said.

El Niño

Another noticeable trend in the upcoming forecast is the development of El Niño.

“This past year, we’ve had a Modoki El Niño, which is a baby El Niño – a tiny one. Now, the Pacific is really warming up, and it will be a game changer for a lot of the weather in the lower 48 states,” commented Day.

El Niño weather pattern effects will be more evident in the fall and winter seasons.

“I am seeing a strong El Niño, which is going to makes parts of the United States warmer than normal early in the winter,” he explained.

Going into December, January and February, the forecast indicates increased precipitation across the United States.

“A classic El Niño weather pattern has an increase in precipitation all up and down the West Coast and also especially in the Southwest. We are going to see the southeastern United States get enhanced rainfall as well,” he noted.

This will also help out southern California, where Day expects precipitation in the next six to 12 months.

“This is the type of pattern where California can really get a lot of rain,” he stated.

Strong El Niño weather patterns in recent decades occurred in 2006 and 2007, with the strongest occurring in 1998. Day believes that this year’s weather will be similar to 2006 or 2007.

“It probably won’t be as strong as 1998 because of cold water in the Pacific coming in and putting an end to it,” he explained.

Wyoming

Wyoming’s winter weather may be a bit challenging to predict for the 2015-16 season as it sits on the map between predicted areas of abnormal moisture and abnormal dry weather.

“A lot of times in these El Niño years, we have a very strong jetstream that brings the California storms. The storms track across the southern tier of the country and may not always make the turn north like what we have seen this spring,” he remarked.

If the storms set up too far to the south, Wyoming will experience a dryer season.

“We may have a relatively cool summer,” he noted. “Fall will likely be mild, but then things could change sharply, getting colder by December and January,” predicted Day.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at This email address is being protected from spambots. You need JavaScript enabled to view it..