Sep 17, 2013 - By Katie Roenigk, Staff WriterRiverton has received twice as much precipitation this year compared to 2012, but local forecasters say the weather still hasn't been unusually wet by historical standards.
"I think the significance really is that last year was so dry," National Weather Service meteorologist Brett McDonald said Tuesday.
Since Jan. 1, 5.28 inches of precipitation has fallen at Riverton Regional Airport, more than double the 2.17 inches recorded at the same time last year.
The average value for the year to date is 7.16 inches.
"So when you consider the calendar year ... we're still below normal," McDonald said.
Numbers for the month show a different trend, however. Since Sept. 1, Riverton has seen 1.2 inches of rain - more than three times the normal .34 inch during that timeframe. Last year, only .03 inch of rain fell in Riverton between Sept. 1 and Sept. 17.
NWS officials said a long period of unsettled weather last week brought the "much needed" rainfall to most of western and central Wyoming.
Between Sept. 10 and Sept. 15, 1.15 inches fell at the Riverton airport, with 1.12 inches recorded downtown.
Late summer pattern
McDonald said the recent rain events likely felt a little "out of the ordinary" for residents who are used to seeing more storms later in September and October.
But he said the downfalls have been typical of the late summer so far across the county.
"Your late summer storms tend to be ones where the moisture is more brought up from the southwest, kind of that monsoon-type flow," McDonald said.
"Whereas, when I think of your typical October storms I think of the storms that are bringing the moisture in out of the Gulf of Alaska out of the Pacific Ocean."
Colder storm coming
The latter type of rainfall tends to bring colder temperatures along with it, he said, adding that a system from the Pacific should be heading to Fremont County soon.
"The pattern seems to have definitely shifted," he said.
McDonald forecast scattered thunderstorms for Tuesday and Wednesday followed by a drier weather Thursday through Saturday.
He said meteorologists are happy to see more rain coming.
"With as low as last year was, we're just glad we're getting more," McDonald said. "We just hope we don't go through such a dry year as we had last year."
The Fremont County seat also has seen twice as much precipitation this year compared to last year. So far, 2.06 inches of rain has fallen in Lander in September, and 9.92 inches of precipitation has been recorded since Jan. 1.
In 2012, September's first weeks only saw .14 inch of rain, and 4.82 inches fell between Jan. 1 and Sept. 17.
Normal numbers for Lander are .45 for Sept. 1-17 and 9.33 for Jan. 1-Sept. 17.
"So actually for the year they're ahead of normal," McDonald said.
Over the past five days, areas of Lander have received between 1.57 inches and 2.91 inches of rainfall, according to the NWS.
In Jeffrey City, 1.32 inches of rain fell in the recent storms, with 1.19 inches in Hudson, 1.08-1.17 inches in Dubois and .55 inch at Boysen Dam.
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