Storm blows in wind and rain this afternoon and tonight

Batten down the hatches Minnesota, this should be a good one.

A powerful storm system winds up and races toward Minnesota this Veterans Day. The system deepens rapidly today, driving a combination of wind, heavy rain and some thunder across a big swath of the Upper Midwest.

Storm Headlines:

• Rapidly deepening low pressure arrives this afternoon and tonight

• Veterans Day morning mostly dry

• Rain coverage increases from south to north around midday

• Heaviest rains arrive late afternoon through tonight

• 1- to 2-inch rainfall totals likely with this system from metro south and east

• Winds increase this afternoon and peak tonight.

• High wind warnings are posted for southwest Minnesota

• Gusts 40 to 60 mph likely

Rapidly deepening low

The Ides of November are perfect for rapidly deepening lows in the Upper Midwest. Cold air pools north. Mild late fall air lingers south. The spin-ups deepen quickly and race north.

The latest forecast model trends with this system still favor a Nebraska City-Des Moines-La Crosse-Green Bay storm track, but a slightly slower arrival. That means most of the precipitation may hold off until around midday, then increase from south to north Wednesday afternoon. Winds crank up as the pressure gradient tightens Wednesday afternoon and evening.

A trailing cold low pressure trough and lingering moisture will produce enough cold air and moisture for some snow across northeast Minnesota and northwest Wisconsin Thursday and Thursday night. It looks like enough to shovel and potentially plow across parts of northeast Minnesota and the North Shore.

Borderline "bomb"

This system will deepen rapidly and could approach "bomb cyclogenesis" status. Pressure falls with our inbound low should approach 15 to 20 millibars in 24 hours. At 45N latitude where we live, a "bomb cyclone" need only drop 19 millibars in 24 hours to achieve “bomb” status.

Simply put, bomb cyclogenesis is the formation of an “extratropical area of low pressure in which the central barometric pressure drops at least 24 millibars in 24 hours.” [1] However, it should be noted that this represents the most common case in areas that are north of 60 degrees latitude. Sanders and Gyakum, who coined the term “Bomb Cyclones” set the pressure falls needed to reach bomb status at 19 millibars in 24 hours at 45 degrees and 23 millibars in 24 hours at 55 degrees. -NOAA/UK Met Office

Heavy rain and thunder

The heaviest rainfall arrives tonight. Strong updrafts will support heavy rainfall, and could produce a few embedded thunderstorms from the Twin Cities south and east.We need the rain. It's borderline dry across a good chunk of southern Minnesota. A good deep soaking will help recharge trees and soils before the coming freeze-up in the next few weeks.

Rainfall totals of 1 to 2 inches still look likely from the Twin Cities south the I-90 corridor and east into Wisconsin.

A tighter resolution shot. The National Oceanic and Atmospheric Administration's Global Forecast System model is very aggressive and paints some potential flood producing 3- to 4-inch rainfall totals in communities between the southern Twin Cities and Rochester.

Here's a closer look at model spreads for the Twin Cities, a point-specific forecast for MSP Airport.

Midwest severe outbreak

The powerful cold front cuts into relatively warm and unstable air south of the system. Squall lines and a few tornadoes are likely Wednesday across Iowa, Missouri and Illinois and points south as the trailing cold front races east.

Another mild weekend

My informal unscientific poll shows 87 percent of all Minnesotans are just fine with this warm fall and unbelievable string of nice weekends. Colder temperatures, freezing conditions and snow are still ahead in the coming weeks, but this has been a blissfully mild slow-motion fall across Minnesota. Temperatures through the first 10 days of November are among the warmest ever recorded across much of Minnesota. Duluth has posted the third warmest start to November so far.

This tidbit from the Duluth National Weather Service.

3rd Warmest Opening to a November at Duluth

The average temperature of 45.8 degrees through the first 9 days of November ranks as the 3rd warmest in Duluth recorded history. In 1975, the average temperature was 47.6 degrees, ranking 1st. In 2nd, was 1903 with an average temperature of 46.1 degrees. Interestingly, the monthly snow total for November, 1975 was 25.7 inches.

One more unseasonably mild and sunny weekend arrives after our post-storm cold shot. High in the mid to upper 50s are a good 10 to 15 degrees warmer than average this weekend.