Minnesota’s tropical connection: Heavy downpours again

The soil underfoot in shady areas is a little soggy at the Weather Lab in the west metro these days. It's about to get even wetter.

Our next weather system slogs into Minnesota Wednesday morning. Thunder and more heavy rain creates The Land of 10,000 Puddles as Wednesday unfolds.

Forecast headlines:

• Low pressure with a tropical Pacific moisture connection moves north toward Minnesota Wednesday.

• The system is the remnants of Tropical Depression 16-E.

• This system dumped 2" to 4" of rain on Arizona and caused flash flooding in some areas.

• Expect scattered T-Storms with heavy downpours Wednesday across Minnesota.

• Rainfall totals of 1" to 2"+ are likely.

The system

Here's a look at the surface maps. A slow moving low pressure system lumbers northeast toward Minnesota Wednesday. Scattered rain and thunder develop during the overnight hours, and push northeast through the day Wednesday. Both your morning and afternoon commute look wet, and traffic could be slower than usual. How lovely.

Tropical connection

This system is somewhat rare in that it originated in the tropical Pacific as Tropical Depression 16-E. Occasionally in fall we get moisture from recurving eastern Pacific systems as far north as Minnesota. It may not be the Pineapple Express, but the added moisture will juice this system and enhance rainfall output.

NOAA's water vapor loop takes advantage of wavelengths that isolate and display water vapor in the atmosphere. You can clearly see the rich feed of tropical moisture available as the remnants of 16-E move toward the Upper Midwest. Here's the water vapor loop from College of Dupage.

Also above, note the "spin" (center of vorticity) over the 4-Corners moving into southwest Colorado. That's the upper level low pressure center driving the action. I'm a little concerned that the models may actually be underestimating the rainfall output with this system given the amount of deep tropical moisture.

Scattered storms begin to bust out overnight into early Wednesday morning. Localized heavy downpours greet you on your morning commute. Plan accordingly for extra time. Flash flood watches and warnings are a possibility Wednesday.

Here's a more detailed breakdown of the hours Wednesday and Thursday. Scattered and heavy - the watchwords for rainfall coverage and impact.

Swath of 2"+ rainfall totals?

Iv'e noticed the models and NOAA human massaged rainfall output rising for this system in the past 24 hours. The best efforts at pinpointing the heaviest rain zone seem to favor a Sioux Falls-St. Cloud-Duluth line give or take.

That could still easily shift toward and include the Twin Cities, but the best data suggests heaviest rains west and north of the metro.

Bottom Line: Expect a rainy Wednesday with potentially heavy tropical style downpours and some localized flood potential.

-Latest Twin Cities radar loop

Three seasons, one day?

This tweet from Grand Forks NWS reminds me that we live at a precarious latitude in September. From 91 degrees in the afternoon to 37 degrees the next morning? Priceless.

First metro frost on the horizon?

I'll believe this when it's still there 3-5 days out, but the longer range GFS is finally hinting at a real cold front after the first week of October. The average first frost for MSP Airport is October 6th, so I wouldn't be shocked at this outcome.

Climate Cast: Going big on solar

Yes, climate change is a very real and seemingly daunting global problem. Still, I'm encouraged by the many green shoots that are springing up in the past 2-3 years.

Last night before I spoke at the Climate Generation Minnesota event in Mankato, I heard Mankato City Manager Patrick Hentges describe the solar projects popping up within the Mankato city limits. That kind of local scale power generation by cities is the wave of the future, as solar costs plummet. A free supply of energy from the sun? The falling costs to capture that look more attractive every day. Investment and jobs in clean renewable energy? It's clearly becoming a huge new economic opportunity.

I found this piece of interest on how solar investment and research is reaching boom proportions from Bobby Magill Climate Central.

Researchers developing new solar power technology are getting more than $100 million in grants from the federal government as a way to reduce the cost of solar power and expand access to low-carbon energy.

As part of the Obama administration’s Climate Action Plan, the U.S. Department of Energy on Wednesday announced $52 million in new funding to universities, corporations and national laboratories to find ways to reduce the cost of solar energy, and $50 million for solar photovoltaic technology research and development.

Renewable energy sources such as solar and wind power will help displace coal as a fuel for electric power generation. Electricity production is the largest single source of climate change-driving greenhouse gas emissions in the country, mainly because much of the U.S. power supply is based on coal-fired power plants.

If they are successful, the projects funded this week will contribute to the Energy Department’s goal of having nearly 30 percent of U.S. electric power produced by solar by 2050.

“Since President Obama took office, the total cost of a home solar energy system has fallen by nearly 50 percent, while solar deployment is up twenty-fold,” U.S. Energy Secretary Ernest Moniz said in a statement. “The projects announced today will help more communities nationwide reach the goals laid out in the Clean Power Plan, while ensuring that America continues to lead the world in clean energy innovation.”

The Clean Power Plan, finalized in August, requires states to reduce their carbon emissions from existing power plants using fossil fuels by switching to natural gas and renewables for power generation and becoming more energy efficient.

Of the grants announced Wednesday, $32 million will be used on 14 projects researching how to improve the performance and efficiency of concentrating solar power plants, such as Abengoa Solar’s Solana solar plant in Arizona, which uses mirrors to concentrate reflected sunlight on a central point and then stores that energy in molten salt.

One of those projects is a new thermal energy storage system being developed by Argonne National Laboratory in Illinois. It would boost the amount of energy that concentrated solar plants are able to store, so solar power can be used when the sun isn’t shining. The project will use new highly conductive materials to make concentrating solar plants more efficient.

Other solar research projects funded by the Energy Department will find ways to improve photovoltaic performance and reliability and reduce the cost of solar photovoltaic panels, which are already rapidly becoming less expensive.

Arctic greenhouse gas: A $43 trillion problem?

It's called a feedback loop. The Arctic warms. Permafrost thaws. Huge stores of additional CO2 and super potent methane greenhouse gas are released into the atmosphere. The atmosphere warms faster. More CO2 and methane.

It's one of the wild cards in climate change. The unknown unknowns. The potential cost for a runaway climate warming scenario?

Here's another eye opening piece from Climate Central.

As climate change melts permafrost in the Arctic, huge amounts of carbon dioxide and methane are released into the atmosphere, speeding global warming in the process. A new University of Cambridge study shows that by the end of the 22nd century, the global economic toll of those greenhouse gases will total $43 trillion.

The study, published Monday in the journal Nature Climate Change, shows that permafrost soils contain roughly 1,700 gigatonnes of carbon locked in frozen organic matter, which has begun to thaw as the globe warms. Until now, there have been no estimates of the economic costs of releasing that carbon into the atmosphere.

The study assumes that by 2100, humans will have stopped emitting greenhouse gases from burning fossil fuels and atmospheric carbon dioxide concentrations will have reached 700 parts per million (it reached 400 ppm globally for the first time in May).

A widely-used model estimating the social cost of carbon emissions placed the global economic price tag of anthropogenic greenhouse gas emissions at $326 trillion by the year 2200. This week's study shows that emissions from melting permafrost add $43 trillion to that total, ringing up the total cost of climate change at $369 trillion by the end of the next century.

Thawing permafrost is likely to cause tens of trillions of dollars of additional climate impacts around the world,” study lead author Chris Hope, reader in policy modeling at Cambridge, said. “It’s the first time the economic impacts of thawing permafrost have been estimated. The impacts can be greatly reduced if we move to an aggressive abatement pathway.”