HAPPY WINTER SOLSTICE!The winter solstice will occur Saturday morning (Dec 21), officially, at 11:11 am CST. At that time, the earth's spin axis will be oriented so that the sun appears to be the farthest south in the local sky (midday over the Tropic of Capricorn in the Southern Hemisphere). While most of us consider this event to be the start of astronomical winter, the British call this day the "Midwinter Day", as the apparent sun will begin its northward climb again, back toward the equator. For essentially all locations in the Northern Hemisphere, Saturday night will be the longest of the year. On a brighter note, starting Monday the length of darkness will begin to shrink as we head toward the summer solstice on 21 June 2014.
Some reports of heavy snow this monthSnowfall has been both frequent and heavy for many observers in Minnesota this month. Both International Falls and Duluth report snowfall on 12 of the first 20 days. Many northern observers have recorded over 20 inches of December snowfall so far, including International Falls, Cass Lake, Grand Rapids, Leech Lake, Babbitt, Chisholm, Floodwood, Grand Marais, Grand Portage, Bruno, Cloquet, and Wright. Areas around Two Harbors have reported over 40 inches of snowfall. According to the DNR areas along the north shore of Lake Superior are reporting snow depths in excess of two feet.
Spell below 32 degrees F ends in the Twin CitiesThe cold and snow dominated Minnesota over the December 4-17 period, producing 13 consecutive days of temperatures below the freezing mark (32 F) in the Twin Cities. Though somewhat troublesome for not melting the snow on our roads and highways this spell of below freezing temperatures was no where near a record for the month of December. In both 1972 and 2000 December brought 26 consecutive days with temperatures below 32 degrees F, while in December of 1983 the thermometer never reached the 32 degrees F mark in the Twin Cities.
Besides prolonged cold temperatures, some nights have brought temperatures of -30 degrees or colder to several communities in the north, including Cass Lake, International Falls, Cook, Babbitt, Hill City, Ely, Floodwood, Gunflint Lake, Hibbing, Orr, Tower, Brimson, and Embarrass. A reading of -38 degrees F at Brimson on the 8th is the coldest for the month so far. Minnesota has seen the coldest temperature in the nation on at least four dates during the month and a number of new daily low temperature records have been set. Some of the more notable ones have been:
-38 degrees F at Brimson on the 8th
-32 degrees F at International Falls on the 15th
-29 degrees F at Cass Lake on the 8th
-27 degrees F at Itasca State Park on the 12th
-19 degrees F at Browns Valley on the 7th
-17 degrees F at Windom on the 12th
In addition on both December 13th and December 15th strong winds combined with the cold temperatures to produce dangerous Windchill values that ranged from -30 to -40 degrees F. And finally, most observers are reporting average monthly temperatures so far that are 6 to 12 degrees colder than normal, marking the coldest December since 2000.
Weekly Weather PotpourriNOAA features a report on the Arctic weather and climate conditions of 2013 on their web site this week. Continued trends toward a greener and warmer Arctic landscape were in play during 2013. You can read more about this on NOAA's website.
If you like you can also stay on the NOAA web site and read about the climatology associated with a White Christmas. A complete geographical depiction of the chances for a White Christmas are mapped and described there in great detail here.
The United Kingdom Meteorological Office announced this week the results of a new study which shows that in many areas of the globe the frequency of river flooding will increase with climate change. In addition some peak flow volumes may change as well. The study combined the results of both climate models and river flow simulations models for a number of different regions. You can read more about it at the UK Meteorological Office's website.
Among other the weather stories of 2013 the impact of Super Typhoon Haiyan on the Philippines was voted the top story of the year by the BBC. The Australian Heat Wave and Wildfire season was also voted among the top weather stories of 2013. You can see the BBC program on these storms and others on their website.
Two strong tropical cyclones formed in the Southern Indian Ocean this week. Cyclone Bruce, southeast of Diego Garcia, was producing winds well over 130 mph and sea wave heights of 30-35 feet. It was expected to remain at sea and dissipate by Christmas Day. East of La Reunion Island Cyclone Amara was spinning and producing sea wave heights of 30-35 feet with winds over 120 mph. It too was expected to remain at sea and dissipate by Christmas Day.
This week there was further revelation about the EPA Climate Policy Expert (John Beale) who committed nearly a decade of fraud. He was sentence to 32 months in prison. This is an embarrassing story for the EPA and who it relied on for climate policy advise. You can read more here.
MPR listener questionLast spring when the cold seemed to go forever, it was partly blamed on global warming (climate change) breaking down whatever weather mechanisms hold cold weather to the north. Is that what's going on now? I seem to recall that it also had something to do with changes in the jet stream.
Answer: Indeed, an unusual jet stream pattern prevailed last spring which kept temperatures cooler than normal and brought frequent and heavy precipitation (record-setting in southeastern MN). A somewhat similar pattern prevailed for the first 2.5 weeks this month, but the jet stream has recently flattened out (more west to east orientation), bringing us more moderate temperature conditions. It is an oversimplification to ascribe this jet stream pattern solely to climate change in the Arctic latitudes. It may have something to do with the jet stream configurations we are experiencing, but it is likely more complicated than that involving oscillating behaviors in the pressure patterns and sea surface temperatures of mid to high latitude positions.
Twin Cities Almanac for December 20thThe average MSP high temperature for this date is 26 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 10 degrees F (plus or minus 14 degrees F standard deviation).
MSP Local Records for December 20th
MSP weather records for this date include: highest daily maximum temperature of 51 degrees F in 1967; lowest daily maximum temperature of -11 degrees F in 1916; lowest daily minimum temperature is -24 degrees F in 1916; highest daily minimum temperature of 39 F in 1923; record precipitation of 0.74 inches in 1902; and a record 4.6 inches of snow fell on this date in 2010.
Average dew point for December 20th is 9 degrees F, with a maximum of 44 degrees F in 1967 and a minimum of -30 degrees F in 1963.