The Weather Wire
October 2008 Volume 16 Number 10
Avg High - 76.0
Avg Low - 47.5
Snow - 0.0"
Season Snow - 0.0"
Precipitation - 1.04"
Avg High - 66.0
Avg Low - 35.9
Avg Snow - 4.1"
Avg Precip - 0.99"
What does this winter have in store for the Front Range of Colorado? Well, as you all know snowfall can be highly variable from year to year and location to location, but Skyview Weather believes that a persistence forecast in tandem with Colorado’s “normal” climatology in mind can give a reasonably accurate forecast for this winter season.
As of the 1st of October the early fall season has been very mild without a frost or freeze along the I-25 corridor. The longer range models are currently hinting at a more active weather pattern beginning this weekend which will put an end to the string of above normal temperatures we have seen recently. Speaking of temperature, the mean temperature which takes into account the high and low has been at or below normal for every month except one all the way back to October 2007. This trend of near normal to below normal temperature will likely continue into the winter season. What does that mean? Well the snow that falls will last longer, especially on north facing slopes with areas of ice due to the freeze thaw that occurs between day and night.
Precipitation has been lacking so far this year as we are more than 4.0” below normal to date. There are not any signs that this pattern will change significantly in the near future. As a result this winter will likely feature near normal to slightly below normal snowfall for many areas along the Front Range. Some specific locations that will likely receive more snow than last year are Colorado Springs and northeastern areas of Denver. Both locations will likely receive more snow, plainly due to the fact that snow totals were well below normal in these areas last year, especially in and around Colorado Springs.
As many of you remember there was a relatively high frequency of snow producing weather systems ranging from trace amounts up to the big snows in December. With the northern branch of the jet stream being the dominant feature again this year there will likely be a high frequency of storms ranging from weak disturbances to stronger, 24-48 hour storm systems. Highest snowfall months will likely fall in line with climatology: November, December, February, March and April. Last year January was above normal in snowfall and will likely be near normal this year. As always, there will be a chance for a “big” snow with the best chances in the late winter/early spring on normal years. Last year the largest snowfall came in December and with a slow start we have witnessed so far this year it would not be surprising to see some significant snow again in December this year. If this December does produce above normal snowfall it will likely remain on the ground for quite some time (like last year) due to the suns angle being at its lowest point in the sky.
To sum it all up, Skyview Weather believes that the winter of 2008-2009 will be at or below normal in temperature, near normal to slightly below normal in snowfall with an active weather pattern producing a higher than normal frequency of snow events ranging from numerous small storms of TR-3”, 3-5 storms of 4-8” and 1-2 storms of 12” or more. As always there will be locations that buck the trend and end up significantly higher or lower than surrounding areas due to the highly variable terrain and the effects of rain/snow shadowing from the Palmer Divide, Continental Divide and the Cheyenne Ridge.
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 October 2008. As can be seen, it is expected that virtually all of Colorado to have normal temperatures for the month of October 2008. The exceptions being the extreme southern portions of Colorado where slightly warmer temperatures than average are anticipated.
The map below shows forecasted precipitation deviances for October 2008. Normal precipitation is anticipated for all of Colorado.
Drought conditions are expected to improve across southeastern Colorado over the next 3 months, with no change expected other area of the state.
September of 2008 was a near normal month in both precipitation and temperature. The end of the 90 degree weather came to an end with the warmest day of the month posting a temperature of 87 degrees. There was not a freeze or frost this month with the lowest temperature being only 40 degrees, which is rather warm. The mean temperature for the month was 61.8 degrees which is about a half of a degree below normal. Nearly all of the precipitation during the month of September came in the first two weeks with 1.04" total for the month. This was below normal by only 0.10", but the deficit for the year now stands at -4.19". September lived up to its reputation as being one of the sunniest months in Colorado with 67% possible sunshine.
October has a reputation for beginning warm and pleasant at the beginning of the month and cool, wet or snowy towards the end of the month. Believe it or not October is usually the second sunniest month in Colorado just after September. As far as temperatures for the month there can be a wide range from 90 degree weather to single digits and teens. I am sure many of you remember some epic October snow storms such as the 1997 blizzard that dumped 21.9" of snow at the Stapleton site. Snow from that storm remained on the ground through March in many foothill and Palmer Divide locations. It is unlikely that a storm like that will be experienced this year, but winter usually makes a visit during the month with 4.1" of snow on average. Thunderstorms become very rare with only one storm reported on average.
Sunrise/Sunset (Jul - December Denver area)
May 2008 to September 2008