The Weather Wire
January 2009 Volume 17 Number 01
Avg High - 41.0
Avg Low - 12.3
Snow - 10.3"
Season Snow - 12.0"
Precipitation - 0.24"
Avg High - 43.2
Avg Low - 15.2
Avg Snow - 7.7"
Avg Precip - 0.51"
2008 Year in Review
The year of 2008 began and ended very dry in Denver with a somewhat normal thunderstorm season during the summer. There was a major change in climatology this year as the old Stapleton site no longer is the official site for snowfall as of this winter season starting in September. Precipitation has always been reported there, but snowfall has not! Due to this shift in reporting locations it is likely that the new DIA station will report less snowfall on a yearly basis than the Stapleton site which will make snow amounts appear lesser on average than actuality for years to come. Eventually, as years pass the average annual snowfall for Denver will drop due to this location change, likely to under 60.0” per year as we average 61.7” currently. Besides the change in reporting locations there was some noteworthy weather that occurred in 2008. The consecutive 90-degree streak that was broken this year was probably the most noteworthy weather headline. The streak started in July and went through the 5th of August with an astounding 26-day streak. This shattered the old 90-degree day streak of 18 consecutive days. Surprisingly there were not any single day records broken during this streak. The tornado outbreak in Weld County on May 22nd left the town of Windsor with heavy damage as well as other northeastern Colorado communities. Other noteworthy tornadoes that affected the Front Range were the high elevation tornadoes that moved through 11 Mile State Park and tornadoes in northeastern Douglas County that were captured by the media and local spotters. As far as precipitation is concerned 2008 was a rather dry year at least for DIA in both snowfall and total precipitation. Below is a graph of Denver’s monthly precipitation versus normal:
As can be seen by the graph there were only two months out of the year with above normal precipitation. Other areas of the metro area fared better with annual precipitation, but DIA ended up receiving only 10.21” of precipitation versus 15.84” on average. This was 33% below normal for the year. Thankfully there was some good snow measured in the late part of 2007 because there was below normal snowfall for the January through April period with a small bump up in May. Below is a graph of monthly snowfall versus average for 2008:
So far this winter season we have been below average every month except December and the snowfall in December had very low water content which resulted in a monthly deficit of 0.39” of precipitation. With the lack of snow during the early part of the winter it will take some big spring snows to get back to near normal for this winter.
Temperatures in 2008 ranged from well above average to well below average with a year that was slightly below normal in temperature as a whole. Below is a graph of average high temperatures for the month versus normal:
Here is a graph of average low temperatures versus normal:
Here is a graph of monthly mean temperatures which is the best description of how relatively warm or cold we are for the year as it takes into account the highs and lows. Below is a graph of monthly mean temperature in Denver:
There were 7 months of the year with below normal mean temperature and one month was exactly average. That leaves only 4 months with above normal temperatures in 2008 and leaves us with a slightly below normal year as far as temperatures is concerned.
Looking forward to 2009 the near normal to slightly below normal temperatures are expected to continue with at or below normal precipitation for the Front Range and normal to above normal precipitation for the mountains which is where we get most of our water.
Areas of drought are spreading across much of eastern Colorado as a result of our precipitation deficit year to date.
The map below shows forecasted temperature deviances for January 2009. As can be seen, it is expected that all of Colorado to have above normal temperatures for the month of January 2009.
The map below shows forecasted precipitation deviances for Januray 2009. Normal precipitation is anticipated all of Colorado for January 2009..
Little overall change or even slight improvement expected statewide, with the exception of far southeast Colorado where drought conditions are expected to persist.
December of 2008 would have been one of the top ten coldest Decembers on record were it not for that last week of wind and warmth. We still ended up well below normal for temperatures with and average maximum of 41.0 degrees compared to 44.1 on average. The average low temperature was 12.3 compared to 16.4 on average. The highest temperature was a balmy 69 degrees on the second, but a very cold arctic air mass produced a record low of -19 on the 15th which shattered the old record of -6 set back in 1951. As far as precipitation goes we were below normal once again with only 0.24" of liquid equivalent. The only bright spot was that we were slightly above normal in snowfall with 10.3" for the month, but obviously this was light powdery, low water content snow. For the year we area more than 5.0" below normal which 33% of our total precipitation in one year.
January is typically the coldest month of the year in Denver. The record low temperature for each day of the month is below zero. It is not uncommon for temperatures to drop below freezing every night. The coldest temperature ever recorded in Denver was -29 degrees on January 9th 1875. Even though January is the coldest month of the year there is usually not an abundance of snow storms. It is the second driest month of the year in terms of total precipitation and only the 5th snowiest month. An exception to this was in recent history was in 1992 when 24.3" of new snow fell during the month making it the snowiest January in Denver history. The weather during January can be quite changeable with blasts of arctic air usually bringing several light snows and sub-zero temperatures. On the other hand, Chinook winds may blow as high as 100mph in and near the foothills. Chinook wind storms are more common in January than are Blizzards.
Sunrise/Sunset (Jul - December Denver area)
October 2008 to April 2009