The Weather Wire
January 2010 Volume 17 Number 01
Avg High - 36.4
Avg Low - 11.9
Snow - 11.1"
Season Snow - 37.6"
Precipitation - 0.45"
Avg High - 43.2
Avg Low - 15.2
Avg Snow - 7.7"
Avg Precip - 0.51"
2009 Year in Review
Looking back at 2009 the year began rather dry and mild without much snow for the months of January and February. Towards the end of March the storm track became more active and between the 25-27th the seasons largest snow occurred for many areas below 6,500 in elevation. April continued to produce snow with 5 measureable snow events and on the 16-18th many foothill locations above 6,500 received between 1-2 feet or more of snow with lower elevations mixing with rain resulting in much lower snow totals but overall liquid amounts were high especially west of I-25. The last two months of spring made up for a winter lacking in snow and pushed seasonal snow totals to near normal for most locations except Colorado Springs, DIA and some Larimer County locations. This wet weather pattern that developed in the spring would continue into the summer months with a very active and wet thunderstorm season for many Front Range communities north of the Palmer Divide. The months of June and July in particular would provide over 8.0 of rainfall which is more than half of what Denver averages in an entire year! Below is a graph of monthly precipitation at DIA versus normal.
Notice the three spikes of well above normal precipitation and 8 months of below normal precipitation.
As summer came to a close August and September were on the dry side, but October would prove to be a very cold and snowy month with an early season blizzard bringing more than 16-24 of snow to the Denver suburbs. November and December would produce near normal snowfall with many areas already up to 60-75% of an entire winters worth of snow and we still have the 2 of the top 3 snowiest months to come in March and April! Below is a graph of yearly snowfall at DIA:
Temperatures in October would be extremely cold for historical standards becoming the 2nd coldest October on record. Average high temperatures in October were more than 11 degrees below normal. December would also be cold for Colorado standards finishing as the 7th coldest December ever record. Below are graphs of high and low temperatures at DIA for the year:
Notice how the trend was above normal temperatures for the first 5 months of the year then the last 7 months except September and November have all been below normal.
2009 proved to be a rather cool and wet year with a total of 18.12 recorded at DIA versus 14.79 on average resulting in a surplus of 3.33 for 2009. DIA was actually rather low on annual precipitation this year compared with other areas with many locations reporting over 20.0. Here are some other Front Range yearly precipitation totals (reminder these yearly totals are not official, but will represent the locations fairly well):
With the widespread precipitation of the last several months few areas of drought remain over Colorado, though some dry areas have developed in southwestern Colorado.
The map below shows forecasted temperature deviances for January 2010. As can be seen, normal temperatures are expected statewide, with the exception of far northwest Colorado where above normal temperatures are expected.
The map below shows forecasted precipitation deviances for January 2010. All of Colorado is expected to have normal precipitation for January 2010.
Little in the way of drought remains in Colorado, with the exception of a small area in far southwest Colorado where any areas of drought are improving..
December of 2009 was unusually cold with an average maximum temperature of 36.4 compared to 44.1 normally. This was 7.7 degrees below normal and ranks December of 2009 as the 7th coldest on record. Along with the cold came some snow with 11.1" reported at DIA which is 2.4" above normal and results in a 10.7" surplus so far this winter season. The snow had little water content and the month actually fell below normal as far as melted precipitation with only 0.45" compared to 0.63" on average. For the year Denver finished above normal in total precipitation by over 3" and many Denver suburbs were well well above that! It has been quite awhile since we finished a year above normal in precipitation and the wetter than normal trend looks to continue into 2010.
January is the driest winter month for the Front Range and it is also the coldest. Along with the cold air comes limited moisture with around 2-4 storms on average with each producing 1-3" type snowfall. There are not typically any "heavy" snows during the month with 7.7" of total snowfall on average. The unusually cold December has spilled over into January with below normal temperatures and near normal snowfall anticipated. Average highs for the month are in the lower 40s with overnight lows typically in the teens. The sun angle is still low during the month even though we add daylight each day and the snow is typically tough to melt as the ground is frozen solid.
Sunrise/Sunset (Jan - June Denver area)
Sept 2009 to Apr 2010