Sunday, December 14, 2014

From 50s to Slush in 18 Hours - No "Pause" in Global Warming

50 F. high in the Twin Cities Sunday.
27 F. average high on December 14.
16 F. average high on December 14.

1/10th of an inch of snow has fallen during the first 14 days of December.
5.7" snow should have fallen since December 1.
8.9" snow fell between December 1-14, 2013.

December Puddles

Emerging from hibernation can be awkward. "Let me be the 100th person to ask if we're having a white Christmas" my neighbor, Teri, asked me yesterday. Not looking good, I answered. It could be the first brown Christmas in 3 years. "Can you explain that to 7 family members driving up from Texas? One of them has never seen snow. He will be crushed" she sighed.

Snow for Christmas is no longer a sure thing. Winters are becoming ever-weirder. More volatile. According to Dr. Mark Seeley Minnesota has seen a 4X increase in mid-winter rain and ice since 2000.

Exhibit A: today. Expect moderate rain as temperatures fall through the 40s. An inch or two of slushy snow piles up tonight at the tail-end of the storm - the same storm that clobbered California with flooding rains, mudslides, even a small tornado in the skies above L.A. Friday.

Here's what I believe: we'll see our fair share of cold fronts and snowstorms this winter. But El Nino will take the edge off the coldest air. I would wager a (stale) bagel that this winter won't be as persistently bitter as last.

After cooling off to average this week with a rare sunshine sighting expect another thaw just in time for Christmas.

Slushy Monday Night. Models are converging on an inch or two of snow for the Twin Cities tonight, maybe a little more north and west of MSP, less south and east of the downtowns. Although I don't expect much snow, temperatures falling into the 20s will ice up any wet wet, slushy roads after 6-7 PM or so.

Advisories and Warnings. The Twin Cities office of the National Weather Service has issued a Winter Weather Advisory for Carver and Wright counties, deeper in the cold air, for a few inches of accumulation from late afternoon into the wee hours of the morning. Winter Storm Warnings are posted from Marshall to Montevideo to Willmar for some ice and 3-5" amounts.

60-Hour Snowfall Animation. An area of rain rotating north (the soggy remains of the massive storm that smacked California late last week), and then as the column of air overhead rapidly cools a changeover to snow is likely from southwest to northeast across the state by late afternoon and evening. NAM guidance: NOAA and HAMweather.

Nuisance to Plowable. The best chance of enough snow to shovel and plow comes over southwest Minnesota this afternoon into tonight, some 3" amounts near Willmar and LIttle Falls, closer to 1-2" from St. Cloud into the Twin Cities. I expect mostly rain up until late afternoon; probably wet roads for the Twin Cities for the drive home later today, but increasingly slushy roads after 7-8 PM.

The Inevitable Correction. After pushing into the low 50s over the weekend temperatures drop through the 40s today, reaching the 30s by late afternoon. Rain ends as a period of wet snow tonight, and then dry weather prevails Tuesday into Monday, the 22nd. European guidance hints at a mix next Tuesday; if we do see a white Christmas (1" or more on the ground) it'll be by the skin of our teeth.

No Tailwind for Santa. Prevailing winds from December 20-24 are forecast to be from the west-northwest, blowing more Pacific air into the Lower 48, moderating just how cold it can get through Christmas. We're due for a temperature correction, which may be shaping up for the last few days of 2014. Map: NOAA.

Extended Outlook: Colder, But Not Exactly Polar. NOAA's GFS model shows little change in prevailing jet stream winds by the end of the month, but colder air will begin to drain southward over Canada, setting the stage for a real cold front in time for New Year's Eve festivities. Map: GrADS:COLA/IGES.

Christmas Thaw - Much Colder By New Year's Eve. Long-range GFS numbers show highs above freezing Christmas Eve and Christmas Day; not one of our whiter Christmases in recent years. Highs may hold in single digits and teens the last few days of December as a series of real cold fronts take a test drive overhead.

Maps: Tornadoes in California Aren't As Rare As You Might Think. Gawker does a good job of putting Friday's (tiny) tornado in south Los Angeles into perspective; here's an excerpt: "...Between 1950 and 2013, there were 403 confirmed tornadoes in California, coming out to an average of around 6 or 7 tornadoes per year. The vast majority of them occurred in the Central Valley, but you can see a tight cluster of tornadoes down around Los Angeles. Most of the twisters are weak, with 66% of those surveyed by meteorologists rating either F0 or EF0 (we switched from the Fujita Scale to the Enhanced Fujita Scale in 2007). A handful of tornadoes recorded in the state have been significant, with 23 clocking in at F/EF2 and two achieving F3 status..." (Map credit: Dennis Mersereau, The Vane).

"How's The Weather?" Becomes a Loaded Question. Yes, we are all armchair meteorologists (and climate experts) now. Here's an excerpt from a New York Times article: "...According to a recent report by the World Bank Group, extreme weather events could become the new “climate normal.” In this world of “increased risks and instability,” it seems we find comfort in being armed with the facts. With access to the storm-surge of information on our smartphones, we are all meteorologists now. Just a few years ago, terms like extreme snowfall or polar vortex were familiar only to professionals; today, they are bandied about in coffee shops and office elevators..."

The Pilots of Instagram: Beautiful Views From The Cockpit, Violating Rules of the Air. Yes, if I was a pilot I'd probably be taking (illegal) selfies with me and the weather out the cockpit window too - so I sympathize. The FAA may not be so sympathetic. Here's a clip from Quartz: "The pilots of Instagram are internet famous. Their stunning photos of the skies, captured from their unusual perspective inside the cockpit, garner hundreds, sometimes thousands of likes from fans. But taking photos, or using most any electronic device, while piloting a commercial aircraft is prohibited by American and European regulators. Pilots for airlines large and small, flying planes of all sizes, seem to be violating the safety rules, taking photos with their phones as well as GoPro cameras mounted inside the cockpit..." (Images above: Instagram).

TODAY: Periods of rain ends as temperatures fall. NE 10-20. High: 48 early, reaching upper 30s by late afternoon.
MONDAY NIGHT: Wet snow, an inch or two possible. Getting slippery. Low: 26
TUESDAY: Slick start. Mostly cloudy with a colder wind. Feels like 15F. HIgh: 27
WEDNESDAY: More clouds than sun, chilly. Wake-up: 14. High: 23
THURSDAY: Risk of spying the sun. Still brisk. Wake-up: 13. High: 25
FRIDAY: Sunny peeks, good travel weather. Wake-up: 15. High: 28
SATURDAY: Light winds, average temps. Wake-up: 18. High: 30
SUNDAY: Still gray, quiet for late December. Wake-up: 19. High: 31

* File photo: Robert F. Bukaty, AP.

Climate Stories....
Global Average Temperature Cools A Bit in November, But No Pause in Global Warming - And There Never Was One. A long headline, but Discover has a very good article explaining the fallacy of the alleged "temperature pause". The vast majority of extra heat is going into the world's oceans, which may accelerate sea level rise and fuel stronger hurricanes. Here's a clip: "...In fact, as many papers pointed out, there has been no real overall pause: the Earth system has been continuing to accumulate heat, thanks to humankind’s emission’s of carbon dioxide and other greenhouse gases. It’s just that a lot of that heat seems to have been going into the oceans, slowing the rise in temperatures at the surface. Moreover, it’s important to emphasize that each of the last three decades has been warmer at the surface than every preceding one back to the start of modern record keeping in the 1880s..."

Graph credit above: "Global average temperature trend, 1998-present." Source: Stefan Rahmstorf/RealClimate.

Weather Bombs, Polar Vortex: Global Warming's Influence on Extreme Weather. No, it's probably not your imagination. Here's an excerpt from Stanford and Science 2.0: "...The media are often focused on whether global warming caused a particular event," says Diffenbaugh, who is a senior fellow at the Stanford Woods Institute for the Environment. "The more useful question for real-world decisions is: 'Is the probability of a particular event statistically different now compared with a climate without human influence?'" His belief is based on three elements of varying rigor: climate observations, climate computer simulations which estimate variations in climate and statistics to reconcile the first two..."

What We Learned About Climate Change in 2014, in 6 Scary Charts. Here's an excerpt from ThinkProgress: "...The 2014 chart I consider the most important is not the prettiest or simplest. But it is the one that best captures our latest understanding of what has emerged as the greatest danger to humanity this century from human-caused climate change — Dust-Bowlification and the threat to our food supplies. This map of the global drying we face uses the Palmer Drought Severity Index (PDSI), a standard measure of long-term drought. It is excerpted from the study, “Global warming and 21st century drying...”

Graphic credit above: "Palmer Drought Severity Index (PDSI) for 2080-2099 with business-as-usual warming. By comparison, during the 1930s Dust Bowl, the PDSI in the Great Plains rarely exceeded -3 (see here)." Source: Cook et al. and Climate Progress.

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