The Weather Wire
December 2007 Volume 15 Number 12
Avg High 55.6
Avg Low 27.2
Snow - 2.5"
Season Snow - 5.5"
Precipitation - 0.20"
Avg High 44.1
Avg Low 16.4
Avg Snow - 8.7"
Avg Precip - 0.63"
Revised Winter Forecast
With a rather mild and dry start to the winter season it is likely that this relatively warm and dry weather pattern will continue through the heart of the winter season. The jet stream has been steering storm systems to the north of Colorado into northern Wyoming, Idaho and Montana. These areas have been under a prolonged drought and the precipitation is much needed. As for Colorado, we will certainly see periods of unsettled weather and arctic outbreaks through February, but even with normal precipitation and normal temperatures through this period the Front Range will still end up below average due to the hole already dug through October and November. November is typically the 2nd snowiest month west of the Continental Divide and many areas only received a few inches of snow. Last year the snow started to fly in December and continued through February and it is highly unlikely that we will be able to have another year with such a big storm in December and active storm cycle through January which is typically one of the drier months here east of the Rocky Mountains. Last year the spring was below normal, but a surplus of snow that was deposited in earlier in the season more than made up for the shortfall. This year a more “normal” spring is expected with some late season heavy snowfall, but will it be enough to make up for the slow start? For the remainder of the snowfall season slightly above normal temperatures and below normal snowfall is expected to continue at least through February with more normal conditions in March and April which can typically be snowy months for the Front Range.
Most of Colorado continued to see dry conditions, with little improvement in drought conditions.
The map below shows forecasted temperature deviances for December 2007. As can be seen, much of Colorado is expected to have above normal temperatures for December 2007, with the exception of portions of Northeast Colorado where normal temperatures should be seen.
The map below shows forecasted precipitation deviances for December 2007. Above normal precipitation is anticipated for the foothills and west slope, with near normal precipitation areas east..
Some improvement is anticipated in drought areas of Southern Colorado over the next several months.
November started out as one of the warmest in Colorado history, but a cold snap towards the end of the month pushed this November out of the top ten. The average high for the month was 55.6 degrees about 4 degrees above average. The average low was 27.2 degrees, 3.7 degrees warmer than the average. Only one temperature record was broken this month and it was a record high minimum temperature of 47 degrees on the 10th. The highest temperatures for the month was a balmy 76 degrees on the 19th and the coldest temperature observed was 8 degrees which occurred 2 days on the 21st and 22nd, only 2 days after the highest temperature of the month resulting in a 68 degree temperature swing. November was very dry with only 0.20" of liquid equivalent and just 2.5" of snow. November is usually the 2nd snowiest month of the year and a surplus of snow will be needed in the following months if we are to come back to normal. There were 4 days with dense fog with visibilities less than 1/4 mile which is 3 above normal. On the bright side this November had an unusually high amount of possible sunshine with 85%, the normal value is only 64% so hopefully you were able to get outside and enjoy the above normal temperatures and abundant sunshine.
Officially winter arrives on the shortest day of the year which will fall on December 21st. This day is also called the winter solstice and is the day in which the earth's tilt on its axis is at its maximum. December holds the records for the snowiest month at 57.4" as well as the driest month in Denver history without even so much as a trace of precipitation. Not only can the precipitation be extreme ends of the spectrum so can the temperatures. The record high is 79 degrees and the record low is -25 degrees, that is a difference of 104 degrees! We can remember what happened last year with the big snow storm on Dec 20th, but typically December is the 4th snowiest month of the year behind March, November and April. We have not had a outbreak of arctic air yet this season, but December is typically the time when the first Canadian cold fronts tap into truly arctic air. Temperatures typically drop below zero 3 times during the month of December and highs will not crack freezing an average of 5 times during the month. Be prepared for the cold temperatures yet to come and more snowfall this December.
Sunrise/Sunset (Denver area)
October 2007 to March 2008