Wednesday, December 16, 2015

Freakish December Weather Continues - 48 Hour Cold Front - Near 40F for Christmas Eve?

41 F. high Wednesday at KMSP before the cold front arrived.
27 F. average high on December 16.
30 F. high on December 16, 2014.

.37" rain fell in the Twin Cities yesterday.
.7" snow fell at MSP before a changeover to rain.
2.5" snow fell at Brainerd yesterday.

December 17, 1996: 20 to 40 mph winds combined with recent snowfall produce blizzard like conditions for about a 36 hour period over much of the area. Whiteout conditions are common in rural and open areas. Every county road in Yellow Medicine county was impassable by the morning of the 18th. Travelers heading west were stranded in Clara City as plows were pulled off the road. Wind chills were as low as 60 degrees below zero.
December 17, 1946: Heavy snow is reported along with strong wind across northern Minnesota. Duluth has winds up to 62 mph.

Thunder & Lightning in mid-December? It's Complicated

So this is what December is supposed to feel like. The first half of December was nearly 14F warmer than average in the Twin Cities with 7 nighttime lows at or above 32F. Remarkable.

What's really going on? It's over-simplistic to point to only El Nino. Yes, that's a huge signal, but so is the additional warming of the atmosphere and oceans, which will make 2015 the warmest year on record, worldwide by a very wide margin.

But the Arctic Oscillation (AO) is another big factor in our persistent warmth; a strong positive value reflecting unusually low pressure over the Arctic region. When this happens the dreaded polar vortex tends to stay over far northern latitudes, with fewer intrusions of Siberian air into the USA. We've seen a positive phase most of autumn; no signs of an imminent shift that would divert polar air into Minnesota.

Until and unless that happens we'll see more slop-storms with temperatures near freezing; more neutered cold fronts. Enjoy 20s today and Friday, but Pacific air blows more 30s into town next week; 40F possible by next Wednesday.

Snow? Maybe a cosmetic coating Monday morning.

Can I interest you in a beige Christmas?

* Image credit above: NASA GISS and Hot Whopper.

An Unlikely Alert in Mid-December. My phone was barking yesterday, a series of texts warning of lightning moving in. At first I thought it was bad code or a bug. Then the lightning flashes directly overhead and cracks of thunder convinced me otherwise. Very rare for mid-December.

A Touch of Wind Chill. Yes, we've gotten a little soft. I fear I've forgotten how to shiver - but I suspect it will come back to me, just like riding a bike, right? Models are in fairly tight alignment, meaning a high probability of wind chills in single digits to near 0F by Friday. Source: Aeris Enterprise.

Temperatures Recover Next Week. Models show another streak of daytime highs above 32F from Sunday into Christmas Eve. No sustained polar air in sight yet. I think I said something similar back in late October.

A Feeble December. Yes, it will feel like winter out there today and Friday, but expect a quick temperature rebound over the weekend; upper 30s to near 40F by Sunday with temperatures as much as 10-20F warmer than average much of next week. The early (European) prediction for Christmas Eve: 39F high with temperatures falling into the 20s Christmas Day. A coating of slush is possible Sunday night into Monday morning, but the atmosphere should be warm enough for rain showers the middle of next week. A white Christmas in the metro area? A few piles of slush here and there, but more green than white this year.

10-Day Snowfall Potential. Here is GFS model data, showing Wednesday's plowable snow event from Fargo (8") to Duluth (7"), but very little accumulating snow over the northern tier of the USA into Saturday, December 26. Source: NOAA and AerisWeather.

A Merry (Slushy) New Year's Eve? The flow is still modified Pacific, waves of colder air trying to push southward the last couple days of 2015 as a trough of low pressure pushes across the Rockies and Plains. It may be cold enough to snow, but it's still unclear whether any significant southern moisture will be able to penetrate this far north. Source: GrADS:COLA/IGES.

Monthly Frequency of Thunder at MSP. As you can see, at least since 2000, reports of thunder/lightning at KMSP are exceedingly rare, with no reports the last 15 years from January into mid-February. I wonder if that will change too. Graphic: Iowa Environmental Mesonet.

Manic Meteorology. Wednesday, in the span of 2 hours, like so many others around the metro area, I witnessed rain, hail (pea-size), sleet, snow and sunshine. It was the rough equivalent of 3 seasons squeezed into 120 minutes.

Record U.S. Temperatures are Work of El Nino and Polar Vortex, Experts Say. It's a combination of factors, including what may still wind up being the biggest El Nino since 1997-98. This winter the polar vortex shows no (immediate) signs of dipping south. Here's an excerpt from The Guardian: "...Halpert explained that the polar vortex, a circular swirl of cold air moving around the north pole, varies in pressure throughout the winter season – changes called the Arctic oscillation. High pressure expands the system until the bands of cold wind break along the southbound jet stream, spewing icy weather southward into the US. Low pressure holds the vortex winds wrapped in a closer ring around the pole, trapping Arctic air in the region..."

Image credit: "Polar vortex variations: high pressure (cold breaking into the US) on the left, low pressure (cold trapped to the north) on the right." NOAA.

Positive Phase of AO (Arctic Oscillation). We've witnessed a consistently positive phase of the AO since mid October, a trend which is forecast to continue into early January, possibly longer. Source: NOAA.

The Globe's Hottest Year Just Keeps Getting Hotter. Here's a clip from Climate Central: "...November marks the second month in a row the global average temperature was more than 1°C (1.8°F) above the 1951-1980 baseline period NASA uses. October and now November are the first time in NASA’s dataset that a given month has been a full degree Celsius above average. There’s a telltale sign of El Niño with warmth in the tropical Pacific. But the Arctic is where the real departures from normal were in November. Seriously, look at the map above and the corresponding scale. Temperatures were as much as 18°F (10°C) above normal in the Arctic and parts of Russia..."

Map credit: NASA GISS

Arctic Continues to be Significantly Warmer Than Average. NOAA's has the details; here's an excerpt that caught my eye: "...The graph beneath the map shows annual temperatures for the Arctic (areas between 60° and 90° North latitude) and the globe since 1900. Arctic temperatures (red line) are more variable from year to year than global temperatures (bigger swings above and below average). But despite the variability, a trend is clear: the Arctic has warmed more than the globe as a whole. This amplification of climate change occurs for two main reasons. First is the feedback loop that gets underway as temperatures rise and snow and ice melt. The less snow and ice on the ground or ocean during the Arctic’s long summer days, the more sunlight the ocean and land absorb. The more they absorb, the warmer they get, and the more ice and snow melt..."

November Crushes Temperature Record While 2015 Careens Toward New Milestone. Andrew Freedman has details at Mashable; here's an excerpt: "...New data in from the Japan Meteorological Agency (JMA) and NASA show that November 2015, like many of the months preceding it this year, was by far the warmest such month on record. In fact, in NASA's database, November narrowly fell short — by about 0.01 degrees Celsius — of the record set in October for the largest temperature departure from average for any month since 1880. The warmth in 2015 is being driven primarily by two factors — manmade, long-term global warming plus a near-record strong El Niño in the Pacific Ocean. An analysis by the journalism and research group Climate Central found that manmade global warming is the bigger factor out of the two, which is backed up by the fact that 13 of the 15 warmest years have occurred since the year 2000, including many years that did not have El Niño events..." (Image: JMA).

More Exceptional Warmth Shaping Up For Eastern USA During Christmas Week. Details from The Capital Weather Gang: "...The Eastern United States is just coming off a December “heat wave” this week, and temperatures will slowly fall back to normal by the weekend. But don’t get too comfortable in your winter coats — another warm-up is expected to peak in the days around Christmas, and it, too, has the potential to topple records...." (Temperature anomalies valid Christmas Eve: NOAA and WeatherBell).

Retailers Feel the Heat of Lost Winter Clothing Sales. Not a great time to be selling boots or heavy coats. Here's a clip from The New York Times: "...But despite the rise of weather planning and the use of analytics, retailers large and small say they have been stumped by this year’s warm start to the season, which has pushed temperatures into the high 60s along some parts of the East Coast. In some places, fading rose blooms and drooping flowers still cling to plants along some city streets. Understandably, shoppers are not in the mood for winter coats or boots. Macy’s has already warned that it will need to offer big discounts to sell the winter inventory that is piling up in its stores after a slow third quarter. Nordstrom similarly blamed warm weather for its underwhelming fall performance..."

Photo credit above: "Cherry blossoms are seen on the street in Washington DC on Tuesday due to the warm weather." Photograph: Bao Dandan/Xinhua Press/Corbis.

70-Degree Days in December. What? How much of the record warmth is natural, how much is driven by El Nino and the larger warming trend observed worldwide? Here's an excerpt from The Atlantic: "...Alexis Madrigal, an Atlantic contributing editor, coined a term for such weather: “climate changey.” Scientists repeat that few individual weather events can be linked to climate change, and yet, how can an iced-coffee Advent be normal? Surveying an unprecedented California heatwave, historic flooding in South Carolina, and a strange and perplexing sandstorm in Tel Aviv, he wrote in October: “We need a word that reflects the basic anxiety of not knowing what the weather means anymore.” Climate changey is that phrase. In Madrigal’s telling, climate changey stands in for both the weather event and the mental state. In the 2010s, even when weird weather is enjoyable, it feels like a planetary memento mori. Say goodbye to that white Christmas—more of this is coming, and also, by the way, you may die in it...

Temperature Anomaly Map: Climate Reanalyzer.

Pacific Hurricane, Typhoon Records Keep Falling With Weeks to Go. Supernaturally quiet in the Atlantic, but the Pacific basin has been a different story - here's an excerpt from Bloomberg Business: "...The Accumulated Cyclone Energy index, which meteorologists use to plot the intensity of a tropical season, set a record in the Pacific this year, said Phil Klotzbach, lead author of Colorado State University’s Atlantic seasonal hurricane forecast. The index across the Pacific was 765 through Tuesday, breaking the old mark of 760 set in 1992, he said. In addition, the Northwestern Pacific has had 16 major storms, reaching Category 3 or higher on the Saffir-Simpson scale, which is also a record, Klotzbach said. The previous mark was 15 in 1958 and 1965. On top of that, the Northern Hemisphere saw 26 Category 4 or 5 systems, the strongest on the scale, breaking the record of 18 set in 1997 and 2004, he said..."

Map source: Wikipedia.

2015: Fewest U.S. Tornado Deaths on Record? CBS 58 in Milwaukee has the story - here's a link and story excerpt: "It's been an exceptionally quiet year for tornadoes. In fact, there have been only 10 tornado fatalities in 2015.  If this number doesn't change, it would beat the twelve deaths reported in 1910. Two sources of statistics were combined to create the long period of record. The National Weather Service's Storm Prediction Center keeps a file on tornado deaths since 1950.  Also, one tornado historian added to this study with his database going back to 1875. On average, the U.S. sees 36 EF-3 or stronger tornadoes.  This year there have been just 16.  The violent tornadoes, EF-4 or stronger, usually add up to seven per year.  However, this year, only one happened, just west of Chicago in early April..."

Map source: NOAA SPC.

Rare Tornadoes and "Cricket-Size Hail" Hits Sydney, Australia. Think about it - baseball size hail just doesn't compute Down Under. Here's an excerpt from Yahoo News: "A rare tornado hit Sydney on Wednesday with destructive winds above 200 km an hour (125 mph) and cricket ball-sized hail, bringing down trees and power lines, sheering off roofs and walls and causing flash flooding in Australia's largest city. The Bureau of Meteorology (BOM) issued the rare tornado warning around midday as the dangerous storm swept up the coast from Sydney's south, forcing some international and domestic flights to be diverted to other cities..." (Image credit: Peter Rae, Sydney Morning Herald).

San Diego Vows To Move Entirely To Renewable Energy in 20 Years. Here's the intro to a New York Times story: "Last weekend, representatives of 195 countries reached a landmark accord in Paris to lower planet-warming greenhouse gas emissions. On Tuesday, local leaders in San Diego committed to making a city-size dent in the problem.With a unanimous City Council vote, San Diego, the country’s eighth-largest city, became the largest American municipality to transition to using 100 percent renewable energy, including wind and solar power. In the wake of the Paris accord, environmental groups hailed the move as both substantive and symbolic..." (File image: Wikimedia Commons).

Weirdest Gadgets of 2015. Engadget has a marvelously odd list; here's an excerpt: "...What do you get the drunk bicyclist who has everything? Barring some self-control, how about the Alcoho-Lock Bike Lock?"

Breaking News: It Snowed Up North! My friend, Pete Schenck, snapped this photo up at his place on Ossawinnamakee Lake yesterday - looks like about 3" - just enough to cover up his green lawn.

TODAY: Mostly cloudy, brisk! Wind chills in the teens. Winds: W 10-20. High: 27

THURSDAY NIGHT: Patchy clouds, plenty cold. Low: 12

FRIDAY: Coldest day in sight. Partly sunny, windchill near 0F at times. Winds: NW 10-15. High: 19

SATURDAY: Patchy clouds, not as harsh. Wake-up: 9. High: 29

SUNDAY: Intervals of sun, thawing out again. Wake-up: 26. High: 36

MONDAY: Light snow tapers to flurries. Coating possible. Wake-up: 29. High: 32

TUESDAY: More clouds than sun, fairly mild. Wake-up: 26. High: 36

WEDNESDAY: Marchlike, risk of a passing rain shower. Wake-up: 28. High: near 40

* I snapped the photo above in Denver on Tuesday, after nearly 10" of snow and near-blizzard conditions struck the Mile High City. Yes, I wanted to see snow that bad.

Climate Stories...

Paris Climate Accord is a Big, Big Deal. The pride of St. Louis Park, Thomas Friedman, thinks so. Here's the intro to a recent Op-Ed at The New York Times: "I had low expectations for the U.N. climate meeting here and it met all of them — beautifully. I say that without cynicism. Any global conference that includes so many countries can’t be expected to agree on much more than the lowest common denominator. But the fact that the lowest common denominator is now so high — a willingness by 188 countries to offer plans to steadily and verifiably reduce their carbon emissions — means we still have a chance to meet what scientists say is our key challenge: to avoid the worst impacts of global warming that we cannot possibly manage and to manage those impacts that we can no longer avoid. That is a big, big deal..."

Superior Is One of the More Rapidly Warming Lakes, Study Finds. Jennifer Brooks has the story at The Star Tribune; here's the intro: "The world’s lakes are warming up — even frigid Lake Superior — scientists warn. Dozens of researchers pooled decades’ worth of data from hundreds of lakes and concluded that the world’s lakes are warming even more rapidly than the oceans or the atmosphere. The warmer waters threaten fish populations, ecosystems and fresh water supplies around the globe..."

File photo above: Brian Peterson, Star Tribune. "As Lake Superior struggled to freeze over, pancake ice developed in the bay near Cove Point. Researchers say Lake Superior is warming even faster than the global average."

Will Global Warming Heat Us Beyond our Physical Limits? National Geographic asks the question, based on new research; here's the intro: "If greenhouse gas emissions are not reduced, rising temperatures and humidity wrought by global warming could expose hundreds of millions of people worldwide to potentially lethal heat stress by 2060, a new report suggests. The greatest exposure will occur in populous, tropical regions such as India, Southeast Asia, the Middle East, and Africa. But even in the northeastern United States, as many as 30 million people might be exposed at least once a year to heat that could be lethal to children, the elderly, and the sick, according to the new study..."

Photo credit above: "In India last May, temperatures rose to 120°F (50°C), killing more than 2,300 people—and melting this street in New Delhi". Photo: Harish Tyagi, EPA.

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