The Weather Wire
November 2006 Volume 14 Number 11
Avg High 52.6
Avg Low 36.4
Snow - 9.8"
Season Snow - 9.8"
Precipitation - 1.04"
Avg High 51.5
Avg Snow - 10.7"
Avg Precip - 0.98"
The DIA Drought...
If you read the latest monthly summary from the National Weather Service you would see that we are currently in one of the driest years in Denver history. Normal moisture through October for Denver is 14.20 inches. So far at DIA we have only 7.09 inches through October. This is lower than the driest year ever recorded in Denver since 2002. Through October of 2002 we had 7.19 inches of moisture. Now if you were to look only at this one location you would have to say it has been a VERY dry year so far. The problem is that the Denver metro area cannot be represented by a single point located well to the north and east of the area it claims to represent. Exacerbating the problem is the local media, both radio and TV repeat this number and reinforce this myth that we continue to be in a drought! If you have been following our more comprehensive rain and snow reports that we include in this newsletter or the storm reports, you already know that many areas in Denver and along the Front Range have double, triple or even 4 times the amounts we are seeing reported by DIA. So, why is this?
There are a couple of reasons why DIA is still in a drought and most of the rest of the metro area and the Front Range are not. One is the way the climate numbers are collected and reported. The National Weather Service should produce a more comprehensive climate summary for the Front Range and the Denver metro area that includes multiple reporting locations. This would produce a climate report more representative of what is happening over a wide area and not just a ONE point location. This information is already available for many locations and should be utilized to give better idea of what is really happening across the metro are not just at DIA. Our media needs to be a little less lazy and use this information (there are many sources or we could provide) on multiple locations so that they could better inform the public as to what is happening around the metro area and the Front Range and not just at DIA. How many times have you seen or heard reports this year alone, about flooding in Douglas County or street flooding in downtown Denver or 2 feet of snow in the foothills to the west. Yet, these same media outlets then look at the DIA numbers and pronounce us still in a drought. Are they even listening to what they are saying? Yes the numbers at DIA are the “Official” numbers, but we have many, many locations that keep very good records on rain and snowfall. Why not use them?
The second reason for the drought at DIA is location, and a third reason is topography, actually both are related. DIA and for that matter and old Stapleton where the numbers are collected are located on the plains to the east of the metro area. From Stapleton eastward the topography becomes very flat (plains) and more so for DIA. As you travel west of Stapleton the terrain (topography) becomes increasingly hilly with elevations rising as you approach the foothills. Elevations also rise as you head south through Highlands Ranch into Douglas County rising up to the Palmer Divide. I mention this because more than many areas of the county the weather and hence the resulting climate is dependent on the topography along the Front Range. Here are just a couple of examples. During the summer months thunderstorms form in the foothills and up on the Palmer Divide and then prevailing winds push them eastward on the plains. These areas will see many more thunderstorm days than will DIA which has to be right in the path of one of these storms. Just this past summer DIA seems to miss most of these storms while many areas along the Front Range saw some good rains. During the winter months, much of the snow that falls is the result of upslope flow. Air is forced upward by the rising elevations as you head west. Plains locations and DIA do not benefit from this snow enhancing feature as much as our suburbs in the west metro area or the suburbs in our south metro area and certainly not as much as the foothills to the south and west as was seen just a week ago where 20-24 inches of heavy wet snow fell while Stapleton recorded only 5.3 inches!
Location and topography are the 2 main reasons why DIA continues to be on the dry side. A more comprehensive climate report needs to be prepared and reported by the National Weather Service. Our media needs to look at the metro area in a more comprehensive manner to give a more representative year to date precipitation amount. The results they will find are that while DIA may still be in a drought, the same cannot be said for the majority of the Front Range or the metro area.
Improvement in overall drought conditions across Colorado occurred in October.
The map below shows forecasted temperature deviances for November 2006. As can be seen, normal temperatures are expected for Colorado for November 2006.
The map below shows forecasted precipitation deviances for November 2006. Normal precipitation is expected for all of Colorado for November 2006.
As can be seen in the below map, drought improvement is forecast for portions of Colorado through January.
October 2006 finished with 1.03 inches of liquid precipitation which just inched above the normal of 0.99”. This ended the 11 month streak of below normal months for DIA. As we have said numerous times DIA is not very representative of the Front Range. As is usually the case most areas along the Front Range had much more than the 1.03 inches at DIA from the last snow storm alone.
We had 4 snow events in October, 5.3 inches was recorded between 26th and 27th and 3.5 inches was collected on the 17th and 18th of the month. The other two snows were relatively minor. There were 8 days with measurable precipitation, 4 days with 0.10” or more and one day with 0.50” or more. Annual total precipitation for DIA now sits at 7.09 inches which is 7.01 inches below the normal of 14.20 inches.
Temperatures ranged from 84 degrees down to a low of 22 degrees. The average temperature for the month was 49.5 degrees which was 1.5 degrees below normal. We had 11 days with freezing temperatures which is just slightly above normal. There were no temperature records set for the month.
Even though November is usually a tranquil month with numerous pleasant spring like days, it can also be a snow packed winter type month. In fact, November is Denver’s 2nd snowiest month. March is the snowiest Denver month and April is behind November in third place.
In 1944, November was the snowiest month of the year with 16.9 inches recorded. On the 13th and 14th of the month, 12.1 inches of snow was recorded during the 24 hour period which was more than the total for any other month of that year. In 1991, 29.6 inches of snow was measured at Stapleton, making it the 2nd snowiest November. In 1992, 20.1 inches of snow fell making it the 8th snowiest November and the all time snowiest November occurred in 1946 with 42.6 inches of snow.
November is tied with May as the month with the least amount of sunshine with 64%. That compares to September that has the most sunshine with 74%. The average November temperature is 37.5 degrees with an average high of 51.5 degrees and an average low temperature of 23.5 degrees. Just 7 years ago, November 1999 finished as the second warmest November with an average temperature of 47.1 degrees and just a year later in 2000 the month finished as the second coldest with an average of 28.9 degrees. If nothing else it shows that the weather in Denver can vary drastically from year to year.
The average snowfall for the month of November is 10.7 inches. Our feeling is that for this November we will be about average for the month to slightly above average.
Sunrise/Sunset (Denver area)
October 2006 to April 2007