A powerful early season storm is expected to stick it to Montana and the northern Rockies this weekend. The headlines of the National Weather Service site in Billings, Montana says it all, "Historic winter storm this weekend". Yea, that gets me fired up....
The NWS in Great Falls led with this," Major fall storm still on track". Some of the snow totals in the highest terrain west of Cut Bank could reach up to 50 inches. See the circled area below.
Here are the odds of a foot or more of snow. A 100 percent chance near Cut Bank.
As you can see, many parts of the NW United States have a shot at seeing at least 2" of snow.
Here's the 500mb jet stream pattern showing the classic cold core closed low over Washington State. As that sits and spins over the weekend it will also bring record cold to parts of that area. Here in the Midwest the SW flow ahead of the trough will pull warmth and anomalously deep moisture into the central Midwest.
These are the temperature departures shown next Tuesday. Clowns on the left, jokers on the right.
Moisture anomalies for the Midwest are really extreme for the same time period. Water vapor is shown up to 300% above normal (near record levels) in parts of Iowa.
You can see how the jet is drawing the moisture across the central U.S. ahead of the trough. This is known as a moist conveyor belt. All aboard! With the upper air pattern locked in place through next Thursday occasional showers and thunderstorms will roam the region. It won't rain all the time but when it does the threat for heavy rain will exist. The EURO 10 day rainfall forecast below shows the combined moisture feed from the Pacific and the Gulf dumping significant rain all the way from Mexico to the Great Lakes. That's pretty classic.
If it's not raining at your place by Friday morning chances are high that at some time Friday it will. That rain ends overnight but more should develop in my area Saturday night into Sunday. Rains are likely to be heavy in spots and flash flood watches are possible (at this time none have been issued). Here's what the 3k NAM has for rain totals from the weekend events.
Ready or not, we are now going into a unique pattern for this time of year that will promote an active, wet brand of weather through next Thursday. However, as the saying goes, at least you don't have to shovel it. We'll leave that to our friends our west. Roll weather and have a terrific weekend....TS