Driest Start To December On Record & Nearing Record Cold

It appears as though the “wet” half of our wet and cold La Nina is taking a vacation and she shows no sign of returning anytime soon. Several cities across the Pacific Northwest are currently experiencing their all-time driest start to December on record. In Portland, this is the driest start to December in recorded history. Records in Portland began in 1871 (140 years ago). Through December 15th (yesterday) the Portland International Airport has recorded just .06″ of precipitation for the entire first half of December. That is more than 2.50″ below normal for the month to date. By comparison, the normal Portland rainfall for just one single day in December is more than three times the amount recorded so far this entire month. Rainfall amounts like this are unprecedented in the month of December. This is more like something we would see in the first half of August, not December. A ridge of high pressure has anchored itself near the Pacific Northwest since the start of the month and is steering storm systems well north into Canada. This is not something we would normally associate with a typical La Nina pattern. Longer range models show this pattern is likely to continue until Christmas. This also means we will likely see a return to the fog we experienced earlier this week, caused by a temperature inversion that traps cold air at the surface and warm air above.”

Here are the top 10 driest starts to December in Portland history (1871-2011) through December 15th —

Year / December Precip Through 12/15

2011 / 0.06
1876 / 0.15
1883 / 0.32
1976 / 0.35
1988 / 0.38
1932 / 0.45
1913 / 0.52
1927 / 0.70
1960 / 0.75
2008 / 0.86

Here are the top 10 driest Decembers in Portland history (1871-2011) through the end of the month —

Year / December Precip

2011 / 0.06 (through 12/15)

1876 / 0.88
1976 / 1.38
1944 / 1.90
1985 / 2.19
1988 / 2.37
1990 / 2.40
1978 / 2.51
1914 / 2.56
1984 / 2.56

The December Chill

“Many cities across the Pacific Northwest are also feeling the December chill as well. Portland is currently experiencing its 8th coldest December in history (140 years) 1871-2011 and the 5th coldest at the Portland International Airport (1940-2011). The December average temperature in Portland (through the 15th) is just 36 degrees. That is more than 5 degrees below average for the month to date. So far, Portland has recorded below normal temperatures every single day during the first half of this month. Additionally, Portland has recorded sub-freezing morning lows on 12 of the first 15 days of December. The highest number of December sub-freezing overnight lows in Portland for the entire month is 25 set in 1985. Portland has yet to register a single 50 degree or higher temperature this month. The last time Portland saw a December without at least one 50 degree high temperature was 1985.”

Here are the top 10 coldest Decembers in Portland history (1871-2011) —

Year / December Ave Temp

1884 / 31.6
1985 / 33.0
1919 / 33.6
1990 / 34.7
1978 / 35.2
2009 / 35.6
1909 / 35.6
2011 / 36.0 (through 12/15)
1983 / 36.3
1924 / 36.5

Here are a few select cities from around the Pacific Northwest (through Dec 15th) —

City / Dec 2011 Ave Temp (through 12/15) / Temp Departure From Normal / Dec 2011 Precip (through 12/15) / Precip Departure From Normal

Portland, OR / 36.0 / -5.1 / 0.06 / -2.74

Salem, OR / 35.9 / -4.8 / 0.11 / -3.35
Eugene, OR / 34.8 / -5.4 / 0.10 / -3.97
Medford, OR / 33.1 / -6.7 / 0.01 / -1.73
Astoria, OR / 37.6 / -5.4 / 0.50 / -4.46
Redmond, OR / 28.8 / -2.2 / Trace / -0.59
Pendleton, OR / 27.9 / -6.2 / 0.01 / -0.71
Vancouver, WA / 35.8 / -5.5 / 0.14 / -2.96
Spokane, WA / 26.7 / -1.5 / 0.04 / -1.15
Seattle, WA / 35.9 / -5.1 / 0.06 / -2.64
Yakima, WA / 26.8 / -2.7 / 0.01 / -0.71
Olympia, WA / 33.9 / -4.8 / 0.10 / -3.73

Ave = 32.8 / Ave = -4.6 / Ave = 0.09″ / Ave = -2.40″

Update: Fewest Number of 60+ Degree Days On Record at Portland International Airport

“With 15 days remaining in 2011 and no significantly warmer weather on the way, the Portland International Airport is very likely to set a new all-time record for the least number of 60 degree or higher days in a calendar year. So far in 2011, the Portland International Airport has reached 60 degrees or higher just 169 times which eclipses every other year on record at that location. Records date back to 1940 at the airport. The next closest year to 2011 is 1950 and 1955 which each recorded 172 days at or above 60 degrees. Looking even further back, the last time Portland recorded fewer days at or above 60 degrees was in 1909 (102 years ago) with 160. Records were taken in downtown Portland prior to 1940. The average number of days that Portland reaches 60 degrees or higher in a given year is approximately 200. The lowest was set in 1893 with just 145 days, while the highest was set in 1885 at 244 days.”

Here are the top 10 years where Portland reached 60 degrees or higher the fewest number of times (1875-1947 Downtown & 1948-2011 Airport) —

Year / Number of 60 Degree+ Days

1893 / 145
1880 / 147
1899 / 151
1903 / 159
1901 / 160
1909 / 160
1886 / 164
2011 / 169
1894 / 170
1902 / 170

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Stay Tuned!

Steve Pierce
President, Oregon Chapter of the American Meteorological Society (AMS)
E-mail: stevejpierce@comcast.net
Phone: 503-504-2075
Personal web site – http://www.piercevideo.com/weather.shtml
Oregon chapter of the AMS web site – http://www.ametsoc.org/chapters/oregon

Steve Pierce

Steve Pierce

Steve Pierce is widely known as Oregon and Washington's "go-to-guy" when it comes to fast, accurate historical meteorological research and forecasts. Steve is currently the President of the Oregon Chapter of the American Meteorological Society (AMS). Steve is also recognized as a regional weather commentator and blogger who can be heard on local radio stations and seen in print media outlets across the Pacific Northwest. His Weather Blog is hosted by the Columbian Newspaper in Vancouver. Check it out! He is a third generation resident of Vancouver, Washington and holds a degree in Communications. Both sets of Steve's grandparents migrated to Vancouver during World War II. One set traveled from Lenox, Iowa to work in the Kaiser Shipyards supporting the war effort. The other set came to Vancouver from Olympia, Washington to work as educators for the rapidly expanding Vancouver School District. When the war was over, both sets of grandparents decided to stay in Vancouver and continue raising their families, as did thousands of other families at the time. Those who are most familiar with Steve can attest to the fact that weather is his true passion. His love for "all things weather" began at the age of 7 when Mt. St. Helens erupted in 1980. He was fascinated with which direction the ash plumes were headed. Then came the very powerful windstorm of Friday, November 13, 1981, also referred to as the "Friday the 13th" storm. This was the strongest storm to hit the Portland / Vancouver area since the great Columbus Day Storm of 1962! At age 11, he was asked to publish an extended weather forecast for his elementary school's weekly newsletter. In the 1980's, at age 14, Steve was the youngest of KGW-TV's local "weather watchers" and would phone in his daily Vancouver weather stats to then television meteorologist Jim Little for use on-air. Steve has lived through all of the major Pacific Northwest weather events of the past 30 years, and then some. The most notable events include; the bitterly cold winter of 1978-1979, the record setting snow storms of January 1980, the summer heat wave of August 1981, the windstorms of November 1981 and December 1995, the severe arctic blast of February 1989, the record flood of February 1996, the historic ice storm of January 2004, the Vancouver tornado of January 2008 and the record setting snow storm of Christmas 2008. Not to mention every Mt. St. Helens volcanic eruption in between. With access to the most extensive set of historical weather records available to date, Steve has personally designed and integrated a proprietary system that gives him the ability to quickly locate and manipulate weather data as far back as the 1800's. As one local Meteorologist put it, "Steve has fast access to historical weather data that is needed for media, agriculture, business, personal, historical and other climatological needs. He can quickly manipulate the data in many different ways. His forecasts are also quite accurate, especially at longer lead times." Steve also provides local storm assessments, narratives and weather presentations to the general public, as requested. In his spare time, Steve enjoys spending time with his family, the outdoors, vacationing at his family's coastal cabin and just relaxing! By the way, do you like your weather on the "extreme" side? So does Steve! Whether it is collecting damage assessment data & photos after record setting 125 mph winds at the coast in December 2007, being one of the first on the scene after the January 2008 Vancouver tornado, or feeling (literally) the awesome power of 100 mph wind gusts at Oregon's Crown Point in January 2010, Steve has experienced it all! As Steve says, "don't just love weather, live weather!" Check out Steve's personal weather website at: http://www.piercevideo.com/weather.shtml

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