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Saturday, January 8, 2011

December 2010 Global Weather Extremes Summary

December 2010 Global Weather Extremes Summary
by weatherhistorian, wunderground, January 6, 2011
December 2010 will go down in the record books for a number of extreme weather events from around the world with perhaps the Western European cold wave and snow topping the list. The following is a summary of some of the extreme weather highlights from around the world for the past month.

Big snowstorms and rainstorms were the most notable events for the United States and Canada punctuated at the end of the month by one of the most severe tornado outbreaks in December history in the south-central portion of the United States.

Incredible lake effect snowstorms hammered upstate New York and southern Ontario during the first half of the month (see my previous blog for details about these events). By the end of the month Syracuse had wracked up 72.8” of snowfall, its greatest December accumulation and 2nd greatest single-month amount (snowiest month was January 2004 with 78.1”). On December 10-11th, one of the deepest snows in Minneapolis history buried the city under 17.4” (19.0” in St. Paul). Eau Claire, Wisconsin, registered its single greatest snowstorm on record (for any month) with a 22.0” accumulation (old record 18.5” on February 22-25, 1929). Then came the incredible (and incredibly mis-forecast!) Boxing Day blizzard of Dec. 26-27 in the mid-Atlantic states, with the worst of the storm hammering New York City and New Jersey, where 20-24” and up to 32” (Rahway) fell, respectively. Atlantic City, New Jersey, recorded 20.0” in 24 hours its heaviest such snowstorm on record and wind gusts up to 64 mph resulted in true blizzard conditions. Newark, New Jersey’s 24.2” ranked as its 2nd greatest snow on record. Amazingly, the computer models dropped the ball on this one, and significant snow was not forecast to occur until 36 hours before the first flakes began to fall.

An amazing time-lapse video made by Michael Black records 32” of snowfall at Belmar, New Jersey.

Meanwhile, out West, waves of Pacific storms drenched California under record rainfall with stupendous snows in the Sierra Nevada. Floods and mudslides ruined the Christmas Holidays for some in the southern portions of the state. Bakersfield, California, recorded its single wettest month on record (any month) with a 5.82” total (old record 5.36” in February 1998). To put this in perspective, Bakersfield normally receives a seasonal total (July 1-June 30) of just 6.49”. Bishop, California, was drenched with 4.93” of rain between December 18 and 20, equivalent to what it normally receives in an entire year!

Flooding and mudslides in the Los Angeles region. (photo from

Los Angeles recorded 10.23”, one of its wettest Decembers on record, and 51” of snow fell in 24 hours at Mammoth Ski Resort in the Sierra. What is exceptional about the rains in Southern California (aside from the quantities) is that they have occurred during a moderate-to-strong La Nina, which historically brings unusually dry weather to Southern California.

Over 150” of snowfall was reported at Mammoth Ski Area in the central Sierra Nevada December 15-20. (photo courtesy of Mammoth Ski Resort)

The greatest temperature anomalies occurred in the Deep South and Florida. Key West, Florida, reported its 2nd coldest single month on record with an average of 63.1 °F (its record is 61.3 °F in January 1981). An amazing feat for a December! Most locations in central and southern Florida recorded their coldest December of record.

Colon, Cuba, recorded an all-time record low temperature of 1.9 °C (35.4 °F) on December 15th, only a few degrees above the all-time national record of 0.6 °C (33.1 °F) set at Bainoa in February 1996.

In Canada, wunderground reader 'wobsobs' made the following observation:

A retrogressing low from the Atlantic brought some record-breaking mild temperatures over the eastern Canadian Arctic over the weekend. Baker Lake and Rankin Inlet in Nunavut both hit all time December highs on Saturday, Dec. 18th. Both communities rose above the freezing mark for the first time on record in December. Baker Lake hit +1.1 °C on the 18th, eclipsing the previous monthly high of -1.1 °C on Dec. 25, 1999 (records go back to 1946). Rankin Inlet hit +0.9 °C, eclipsing the previous December high of -2.0 °C on Dec. 17, 2002 (records go back to 1981).

A massive tornado outbreak on December 30-31 struck Arkansas and Missouri. Six EF-3 twisters killed eight, and the total count of 25 tornadoes made this one of the top tornado outbreaks of the entire year.

During the first two weeks of December, floods in Columbia killed 257 people, and at one point 1.9 million people (5% of the country’s population) were affected. On December 6-8, the Panama Canal was closed because of flooding. This was only the 3rd time in history that the canal was closed and the first time as a result of weather.

A heat wave in Argentina, Chile, and Paraguay sent temperatures as high as 44.3 °C (111.7 °F) at Prats Gil, Paraguay, near the all-time record for the country (45 °C/113 °F also set at Prats Gill), on December 11th. Jujuy, Argentina, peaked at 42 °C (107.6 °F) the same day. Huge wildfires near Valparaiso, Chile  blackened 14,000 acres of forest.

The cold wave and snow that engulfed Western Europe towards the end of November continued into December. In fact, on December 21 the temperature fell to -15 °C (5 °F) at Belfast, Northern Ireland, the coldest reading ever measured there. Castlederg reported -18.7 °C (-1.7 °F) for the coldest temperature on record for any location in Northern Ireland (old record -17.5 °C at Magherally in January 1979). For the United Kingdom, December was the coldest such since 1890 with temperatures averaging -5.6 °C (-10.1 °F) below the 30-year mean. A snowstorm December 17-20 dropped up to a 30 cm (12”) of snow over portions of southern England, including London, resulting in massive travel disruptions.

The snow and cold were even more pronounced in the western and northern portions of continental Europe. For France it was the coldest December on record since 1969. In Sweden the coldest in 110 years, and in Germany the coldest in 40 years. Munich, Germany, recorded 52” of snow for the month and Berlin 42”. Poland saw temperatures fall as low as -33 °C (-27 °F) on December 2, and Pozan received a total of 58” of snowfall during the month. Sixty-eight people were reported frozen to death in Poland.

Snow disrupts travel in Amsterdam, Holland. (photo from

The worst floods in 100 years prompted the evacuation of thousands along the banks of the River Dina in Bosnia, Serbia, and Montenegro, with water reaching the second floor of buildings in Foca, Bosnia.

The cause for the severe winter weather in Europe was an unusual high-pressure dome centered over Greenland and extending a strong ridge towards the British Isles. This region would normally be under the influence of an Icelandic low at this time of the year. A persistent low south of the Azores created (in combination with the Greenland high) a strong northeasterly flow over northern and western Europe, ushering in cold continental air.

This plot of Northern Hemispheric pressure compares December 2010 to the normal pattern observed between 1968 and 1996. (images courtesy of NOAA/ERL Physical Sciences Division)

A powerful winter storm blasted Egypt and other parts of the Middle East (see ASIA below) on December 10-12. Three people were killed by collapsing buildings in the port city of Alexandria, where 60 mm (2.3”) of rain fell.

An out-of-season heat wave developed over portions of West Africa in early September with Matam, Senegal, reaching 41.8 °C (107.2 °F) on December 4th. This was the hottest temperature measured in the Northern Hemisphere during December 2010. In Namibia the temperature rose to 42.3 °C (108.1 °F) on December 27th in the town of Keetmanshoop, an all-time heat record for the site.

The same storm that blasted Egypt in mid-December also strongly affected Israel and Lebanon. Winds up to 110 kph (68mph) were recorded in northern Israel, and a Moldavian cargo ship foundered off the coast of Ashdod. Beirut recorded 98 mm (3.86”) of rain in 24 hours on December 11-12, and Zefat, Israel, had a storm total of 174.5 mm (6.87”) on December 10-12. The flooding rains followed an extended hot and dry period in Israel that culminated in a disastrous forest fire Near Haifa on December 1-5. Forty-two people died in the blaze, including the nation’s highest-ranking female police officer, Ahuva Tomer.

Plumes of smoke from the fires in Israel trail out over the Mediterranean Sea. (photo from the Telegraph Newspaper, London)

Abnormally warm weather continued through December in most portions of the Middle East, continuing a trend that began during the summer of 2010. For the 6th straight month, record absolute maximum temperatures have been recorded at various sites in both Israel and Lebanon.

The eastern Siberian ‘pole of cold’ lived up to its reputation in December with Oymyakon reporting a minimum of -59.2 °C (-74.6 °F) on December 24th, the coldest temperature in the world for the month.

The big weather news from Australia in December were the major floods in Queensland towards the end of the month that continue to plague the state as of this writing. It has not been any single major rain event (the heaviest 24-hour rainfall so far reported was 273.6 mm/10.77” at Carnarvon Station in central Queensland on December 27th) that contributed to the flooding but the persistence of the rainfall since tropical Cyclone Tasha made landfall on Christmas Day. For an in-depth report on the flooding see Dr. Jeff Masters' recent blogs.

Another exceptional precipitation event occurred in Western Australia at, ironically, another site named Carnarvon located about 900 km north of Perth on December 17th. An amazing 204.8 mm (8.06”) of rain fell. As Blair Trewin of the Australian Bureau of Meteorology remarked:

"This is not something which normally happens at this time of year to put it mildly -- the monthly average for this site for December (66 years of data) is 1.8 mm, so they got almost twice as much rain today as they have in about 2,000 previous December days put together! (and of the 118 mm in the past Decembers combined, 77 of that fell on one day in 1995 -- before this event the second-wettest December day on record was 5.4 mm).”

The hottest temperature measured on earth for this past month was the 47.6 °C (117.7 °F) measured at Gascoyne Junction, Western Australia, on December 27th. The tiny Australian island of Norfolk, located about halfway between New Zealand and New Caledonia, came within 0.2 °C of its hottest temperature on record on December 29th when a reading of 28.2 °C (82.8 °F) was recorded. On the cold side, the town of Applethorpe in Queensland recorded a minimum temperature of 3.7 °C (38.7 °F) on December 21st. This was the 2nd coldest reading ever measured during December in the state.

The coldest temperature ever measured in the Southern Hemisphere during a December was registered at the Dome A site in Antarctica on December 1st and 2nd: -52.0 °C (-61.6 °F). The previous record was -48.0 °C (-54.4 °F) at Vostok on December 1, 1960.
KUDOS: Thanks to Maximilliano Herrera, Philip Eden, and Blair Trewin for contributing to this article.

1 comment:

jyyh said...

As La Nina develops it drops the atmospheric temperatures, precipitation occurs at higher level as the atmosphere has warmed during the previous El Nino. GW just intensifies this discrepancy between wet and dry times, I think.