Old fashioned October rainstorm moves in

The Weather Lab spruce trees are thirsty these days. Thankfully they're getting a good long drink.

Our next weather system is sliding into Minnesota with rain and cooler temps.  By the time it pulls out Tuesday evening, a good soaking rain of 1 to 2 inches plus will be another link in the chain that erases our late summer drought.

-- Latest Twin Cities radar loop

The first waves of steady, soaking rain swept over Minnesota during the overnight hours. Some 1" to 2" rainfall totals have already been recorded.

At least it's not snow.

The Black Hills of South Dakota will shovel out from yet another winter storm and 6 to 12 inches of sloppy new snowfall. Northern Minnesota may see a few wet flakes with the system Tuesday, but for the most part Minnesota will escape early season snowfall.

Heavier jackets and frost on the pumpkins looks more likely for the metro by this weekend. Our warm October start is history. The weather maps look colder than average for the next two weeks, and may bring a pre-Halloween chill that could last into Halloween night this year.

October rainstorm

This is how they draw them up on the weather maps.

An impressive low pressure storm is tracking toward Minnesota from Nebraska. Here's a cool wind map from http://hint.fm/wind/ that shows how winds swirl into the center of these massive 'full latitude' systems.

As the center of the low pulls closer tonight, the heaviest rains move in. Heavier steadier rains and possibly a clap of thunder linger into early Tuesday morning. Rainfall totals should exceed 1 inch on most of Minnesota, with a band of 2 to 3 inches favoring western and north central Minnesota by Wednesday.

Black Hills snow, again

It could be worse, it could be snowing. The Black Hills are on the cold side of the storm again. High enough in elevation to collect snow at 4,000 to 5,000-plus feet, another 6 to 12 inches is likely through Tuesday.

Here's the National Oceanic and Atmospheric Administration's probability of 4 inches or more, which centers on the Black Hills for Tuesday.

First metro frost this weekend?

Our decade long trend toward later frosts in the metro continues this year. We're now well past the 'average' date of the first 32 degree temp of Oct. 7. We'll flirt with upper 30s and probably some suburban frost later this week, but the best chance for the first 32-degree reading in the inner metro core (Interstate 494 / Interstate 694 loop) at this point looks like Sunday morning, Oct. 20.

Scary cold Pre-Halloween?

The Global Forecast System is hinting at an extended chill in the days leading up to Halloween this year. High temperatures in the 30s in the week of Halloween? The GFS is notorious for overdoing cold air outbreaks a week or two out, but the overall pattern looks supportive of a chilly late October. This could be the year of the 'puffy Halloween costume over jacket and hats' in Minnesota.

Stay tuned!