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Extension > Mark Seeley's WeatherTalk > December 2014

Friday, December 19, 2014

Roller Coaster Temperatures in December

This will be the last Minnesota WeatherTalk Blog until after the New Year.  Please look for a new one on Friday, January 9, 2015


Roller coaster temperatures in December:


After starting the month with many sub-zero F temperature readings around the state during the first week, including a national low of -12 F at Embarrass on the 6th, many Minnesota observers reported 11-12 consecutive days with above normal temperatures and several new daily record warm minimum values and record daily warm maximum values were set over the 13th to the 15th.  In addition MSP set a new all-time record high dewpoint for so late in the month with a reading of 49 F on the 15th, that corresponds to the average dewpoint for early June or mid-September.  A full report on this mild spell of weather around the state is available at the MN-State Climatology Office web site.

With the warm spell much of the state lost a great deal of snow cover recently.  Much of the state has seen little snow this month anyway, with only portions of northeastern Minnesota reporting 10 or more inches.  But the other shoe will drop, as it usually does.  Starting this weekend there will be chances for snowfall before Christmas Day, then much cooler temperatures for the balance of the month with more chances for snowfall between Christmas and New Year's Day.  So snow lovers may yet have a smile on their face by the end of the month.  It is still likely that overall December will end up warmer than normal for most areas of the state.



Santa Forecast:

The North American Aerospace Defense Command (NORAD) will again be tracking Santa as he travels the globe on Christmas Eve.  He has a lot of ground to cover.  You can follow his progress by going to the NORAD Santa web site.

For those of us who live in Minnesota it looks like Santa may have to navigate through some snow on Christmas Eve as there will be some snow showers across the state.  At least temperatures will be normal and not terribly frigid.  I am sure Santa and his reindeer will still appreciate a hot beverage and some cookies left out for his home visits. 

 Weekly Weather Potpourri:

The NOAA-National Climatic Data Center has kept records of climate extreme values for each state.  They are available at their web site and may be of interest to many citizens.  It is evident that a number of all-time record values in each state have occurred over recent decades.  You can find this information at the NOAA-NCDC Extremes Records Section of their web site.

For those who have been light-starved this month, take heart.  The winter solstice (shortest day of the year) arrives at 5:03pm on December 21st.  After that we can begin to expect an increase in day length, albeit very slow at first, only about 9 minutes gain by the end of the month.  However we'll pick up another 55 minutes of gain in day length during January, and even more in February and March.  If you want to check out the relative gains and losses in day length for the Twin Cities area you can go to the NOAA-National Weather Service web site....

Brad Rippey of the USDA offered a California drought update this week:
-Since Thanksgiving, periods of significant precipitation have fallen across California.  In valley locations, rain has boosted topsoil moisture, benefited winter grains, and helped to revive rangeland and pastures.  According to USDA/NASS, 30% of California's rangeland and pastures were rated in good to excellent condition on December 14, compared to just 15% on October 26. 
-The latest U.S. Drought Monitor (Dec 18) indicates that there was a substantial reduction in D4 (exceptional drought) coverage in northern and central California.  Statewide, D4 coverage fell from 55 to 32% -- the smallest area in exceptional drought since early-June 2014.  However, overall drought (D1 to D4) coverage declined only slightly, from 99.7 to 98.4%.  In other words, nearly all of the state remains in drought, although the drought intensity has decreased by one category in parts of northern and central California.

This week the United Kingdom Meteorological Office provided an update on global temperature anomalies for 2014.  It is obvious that 2014 will be among the warmest years measured since 1880 no matter what happens weatherwise for the remainder of the year.

NASA/Goddard Space Flight Center released an analysis this week showing that holiday brightened cities emit increased light intensity that is detectable on the NASA/NOAA Suomi NPP satellite system.  Using the Visible Infrared Imaging Radiometer Suite sensor NASA has routinely mapped the images of "Earth at Night."  These images clearly show brighter, more intense light coming from various cities during the Christmas and New Years holidays in the USA and during Ramadan in the Middle East.

MPR listener question:

 The persistent warmth earlier this week over the 13th to the 15th was remarkable.  I don't remember anything like it in December.  Were any new statewide daily temperature records set?

Answer:


Indeed, at least 12 climate stations reported new daily warmest maximum temperature readings over December 13-15, including readings of 56 F at Redwood Falls, 52 F at Worthington, and 51 F at MSP.  But none of the maximum temperature values were statewide records.  More significantly, December 13-15, brought new record warm minimum temperatures to 121 climate stations in Minnesota, with scores of readings in the 40s F.  Two days brought new statewide daily warm minimum temperature readings: on December 14th Marshall reported a low temperature of 46 F breaking the old statewide record of 40 F set at Red Wing in 1891; and on December 15th Owatonna reported a low temperature of 45 F surpassing the former statewide warm minimum temperature record for the date of 40 F at Winona in 1928.

Twin Cities Almanac for December 19th:

 The average MSP high temperature for this date is 25 degrees F (plus or minus 13 degrees F standard deviation), while the average low is 11 degrees F (plus or minus 14 degrees F standard deviation).

MSP Local Records for December 19th:

MSP weather records for this date include: highest daily maximum temperature of 52 degrees F in 1923; lowest daily maximum temperature of -11 degrees F in 1983; lowest daily minimum temperature is -29 degrees F in 1983; highest daily minimum temperature of 38 F in 1923; record precipitation of 0.51 inches 1968; and record snowfall is 6.4 inches in 1951.

Average dew point for December 19th is 10 degrees F, with a maximum of 39 degrees F in 1918 and a minimum of -31 degrees F in 1955.

All-time state records for December 19th:

The state record high temperature for this date is 60 degrees F at Madison (Lac Qui Parle County) in 2011. The state record low temperature for this date is -52 degrees F at Mora (Kanabec County) and Tower (St Louis County) in 1983. State record precipitation for this date is 1.35 inches at Luverne (Rock County) in 1902; and the state record snowfall for this date is 11.5 inches at Two Harbors (Lake County) in 2008.

Past Weather Features:


A major winter storm crossed the state over December 19-21, 1902 bringing a mixture of precipitation and high winds.  In southern counties much of the precipitation came in the form of rain, while in central and northern counties it was snow.  At least 15 climate stations reported over 1 inch of precipitation and some reported 5 to 8 inches of snow.

December 19, 1923 was the warmest in state history with 35 cities reporting highs of 50 F or greater.  Duluth and Two Harbors reported 51F that day, while Winona reported a high of 55F and a mild low of 37F.

By far the coldest December 19th in state history occurred in 1983.  In fact the entire week before Christmas was one of the coldest in state history.  Overnight lows of -30F were common and 35 communities reported lows of -40F or colder, including -40F at Zumbrota and -41F at Jordan.  The high temperature at Ada was -20F.  Windchill values were dangerously low all day.

December 18-20, 2008 brought heavy snow to many parts of the state.  In southeastern Minnesota Harmony reported 8.5 inches, but in the northeast even heavier amounts were reported with 14 inches at Duluth and nearly 20 inches near Two Harbors.  It was a very snowy December in 2008 with widespread reports of 30 to 50 inches for the month.

Outlook:

Warmer than normal on Saturday with increasing cloudiness and a chance for precipitation by evening.  Continued warmer than normal on Sunday and Monday with chances for mixed precipitation, mostly snow in the north.  Good chance for snow statewide on Christmas Eve, carrying over into Christmas Day. Then cooler and drier for much of next week.

Friday, December 12, 2014

Looking back at 2014 weatherwise

2014 Weather and Climate Highlights:

I was asked to speak about this last week on TPT's Almanac program and I didn't get to cover all the weather and climate headlines from the year.  So here is my list:

-March 31st brought a statistical singularity, a tornado warning and a blizzard warning at the same time to Yellow Medicine County.  St Leo was hit by the tornado.
-Coldest year in Minnesota since 1996.  This is especially noteworthy since it has been the warmest year globally in well over 100 years.
-March 6th brought the highest amount of Great Lakes Ice cover since 1979.
-A delayed spring produced some of the latest ever ice-out dates for Minnesota lakes, including Lake of the Woods (May 21st)
-June brought the wettest month in Minnesota state history, with a statewide mean value of over 8 inches of rainfall, many observers had over a foot of rain.
-Glorious weather during the State Fair helped to bring about record-setting attendance
-A terrific month of October allowed most farmers to harvest late maturing crops
-Lastly, a cold and snowy November was like a "slap in the face."

2014 Tornado Summary:

This week Todd Krause of the NOAA-National Weather Service in Chanhassen, MN  provided a summary of tornado reports across the state this year.  Only 23 tornadoes were reported in the state during 2014, the second consecutive year with a smaller than average number (only 15 reports in 2013).  You can view historical data on tornadoes at the State Climatology Office web site to compare other years.  Among the noteworthy characteristics of 2014: the majority of tornadoes (16) were rated EF-0 (winds<86 mph) and caused relatively little damage; an EF-2 tornado (winds 111-135 mph) was on the ground for nearly 38 miles across portions of Polk and Red Lake Counties on July 21st but shrouded in low clouds and heavy rain it was hard to detect; and two tornadoes occurred in Otter Tail County on September 4th between 4:48 am and 5:45 am, very unusual times for such storms to develop.

 Moderation and Warmth:



Since last Friday (December 5th) temperatures have slowly been moderating and warming across the state.  Nearly every observer has reported daytime highs above freezing and a few places have seen 40F or greater.  The NOAA-CPC keeps emphasizing a warming trend across the country in their mid-range outlook products all the way out to December 24th, Christmas Eve.  In fact there is hardly a place on the USA landscape expected to see cooler than normal temperatures over that interval.  Therefore it is likely that a number of spots across Minnesota will lose their snow cover before Christmas.  For those who dread a Brown Christmas there is hope that an Albert Clipper storm system out of the northwest is expected to deliver some precipitation over Christmas Eve and Christmas Day.  Don't know yet how much.

December of 1822:


In the past during the Christmas season we have talked about historical climate extremes for December.  In my lifetime it was 1983, the coldest December of the 20th Century with 16 nights of sub-zero F temperatures and a mean monthly temperature for the Twin Cities of just 3.7 F in the Twin Cities.  The next closest value in the Twin Cities historical record was a mean monthly temperature of 6.0 F in 1872, when there were also 16 nights of sub-zero temperatures.  These are shivering statistics for December, but they are tame when compared to the temperatures endured by the soldiers at Ft Snelling in December of 1822.  They reported 24 sub-zero F nights, with a mean monthly temperature of just 1.6 F.  On Christmas Day that year the temperature only varied between -13 F and -2 F.  Brrrrrr.....

Weather Potpourri:

A recent paper in the Journal of Geography and Geology by Yuan and Mitchell documents a comprehensive study of climate trends in Minnesota.  Some conclusions from this study: precipitation has increased significantly, especially in the months of May and June since 1985; minimum temperatures have increased significantly; and the length of the growing season has expanded, particularly with an earlier onset in the spring.

A recent paper in Geophysical Research Letters by Indiana University researchers documents an increase in extreme temperatures at the "tails" of the spatial distribution on Earth.  These increases are found to be larger than those associated with the central or mean Earth temperature values.  In the past 30 years warm anomalies are increasing at a faster rate than cold anomalies.  

A new study by the United Kingdom Meteorological Office shows that the probability of having extremely hot summers in Western Europe has increased significantly.  Extremely hot summers that once had a historical frequency of twice per century, are now expected to occur about twice per decade.    

MPR Listener Question:

What's has been the longest lasting snow storm in the Twin Cities area?  It seems that most snowfall lasts for just a few hours up to a day in length.

Answer:

The longest duration of continuous falling snow was from shortly after midnight on December 6th to shortly after 5 pm on December 9th, 1969, a period of 88 hours! This was very light snow, amounting to a total of only 14.0 inches, but the December total snowfall that year was 33.2 inches, an all-time record for the Twin Cities until 33.6 inches fell in December of 2010.

Heavier and more memorable snow storms were not as long-lasting. For example, the Halloween Blizzard of 1991 (over 28 inches of snowfall) occurred over a period of 67 hours, while the Armistice Day Blizzard of 1940 (nearly 17 inches of snowfall) lasted about 55 hours.

Twin Cities Almanac for December 12th:

The average MSP high temperature for this date is 28 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 12 degrees F (plus or minus 13 degrees F standard deviation).

MSP Local Records for December 12th:

MSP weather records for this date include: highest daily maximum temperature of 53 degrees F in 1883 and 1968; lowest daily maximum temperature of -1 degrees F in 2000; lowest daily minimum temperature is -15 degrees F in 1879; highest daily minimum temperature of 37 F in 1928; record precipitation of 0.61 inches 1886; and record snowfall is 4.6 inches in 1941.

Average dew point for December 12th is 9 degrees F, with a maximum of 49 degrees F in 1968 and a minimum of -19 degrees F in 1962.

All-time state records for December 12th:

The state record high temperature for this date is 64 degrees F at Tracy (Lyon County) in 1913. The state record low temperature for this date is -39 degrees F at International Falls (Koochiching County) in 1995. State record precipitation for this date is 3.66 inches at Caledonia (Houston County) in 1899; and the state record snowfall for this date is 18.0 inches at Altura (Winona County) in 2010.

Past weather features:


December 12, 1913 was the warmest in state history, with nearly all parts of the state seeing afternoon temperatures that reached 50 F or greater.  Some western and southern communities reported record values in the 60s F.

December 12, 1995 was the coldest statewide in history, with every spot in the state reporting sub-zero F temperature readings.  Several northern cities reported -30 F or colder, and the temperature never rose above -15 F at Itasca State Park.  Abundant snow cover blanketed the state.

December 11-12, 2010 brought heavy snow and a blizzard to many parts of the state.  The Twin Cities received over 17 inches, and the Metrodome roof collapsed under the weight of the snow.  The Holidazzle parade on Nicollet Mall was cancelled and the MSP Airport was closed for a time.  Blizzard warnings prevailed across southern Minnesota, where Winona reported 23 inches, Lake City 21 inches, Red Wing 20 inches, and Owatonna 14 inches.

Outlook:

Mild temperatures over the weekend with increasing cloudiness and a chance for rain or drizzle on Sunday.  Chance for rain or snow later on Monday and into Tuesday with temperatures returning to near normal levels.  Warmer again toward the end of next week.

 
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