Rain arrives Wednesday night; government shutdown affects National Weather Service

What a difference a day makes in weather.

We enjoyed a blissfully warm and desert dry air mass over Minnesota Tuesday.

But a potent storm in the Pacific Northwest is moving toward Minnesota. Cooler air — and much-needed rainfall — is just 24 to 36 hours away. In the blog today we track the arrival of what looks like fall weather that may be here to stay. And we look at how the government shutdown is affecting some National Weather Service products.

Image: Twin Cities NWS

From desert dry to monsoon wet in 36 hours?

Tuesday’s air mass over Minnesota was blissfully dry. The dew point plunged to 18 at St. James Tuesday afternoon, and 19 at Moorhead and Silver Bay. Dew points in the 20s and 30s are more common in Phoenix or Palm Springs.  Tuesday’s dry air mass was aided by strong “downslope” winds from the northern Rockies. The descending air mass dries out as it falls in elevation on the Rockies Front Range. Here’s the dew point map from Tuesday afternoon showing a  modified “desert Chinook” air mass feeding into Minnesota from the west.

Image: University of Illinois

The incoming air mass is noticeably cooler. Cold air is pooling in the Pacific Northwest and heading for Minnesota by late this week.

Image: University of Illinois

Take a look at the temps trends later this week.

Rain arrives Wednesday night

The first waves of rain arrive in Minnesota by Wednesday night. All signs point to a long duration rainfall event, with several waves of rain between Wednesday night and Sunday morning. Much of Minnesota could pick up 1 to 2 inches or more by Sunday noon.

Image: NOAA via Iowa State University

The more aggressive solutions lay out a “bull’s-eye”rainfall of 3 inches or more over the Twin Cities and central Minnesota in the next five to seven days. If this verifies, it will put a serious dent in our late summer drought.

Image: NOAA

Shutdown affecting some NOAA/NWS products

In my usual search through dozens of weather sits on the web today, I found this.

Image: NOAA

Most NOAA functions are deemed “essential” during the federal government shutdown, but some data is missing today. Your local National Weather Service site is up and running, and most staff is in place.

Image: Twin Cities NWS

Numerical weather models are also up and running. It has been estimated that accurate weather forecast from the National Oceanic and Atmospheric Administration and other sources save the U.S. economy up to $4 billion annually. Talk about penny wise and pound foolish. Let’s hope we get the rest of the data back soon.