2005/06 Winter Outlook for South Central and Southeast Colorado
You may be aware that the Official Winter Outlook was recently re- released by the CPC, with the Temperature and Precipitation Outlook graphics presented below.
Implications for the U.S. in Winter 2005-2006
• El Niño and La Niña are not likely to be factors influencing the winter weather in the United States;
• The winter weather patterns during ENSO-neutral conditions are often dominated by other leading patterns of climate variability, including the Madden Julian Oscillation (MJO) and the North Atlantic Oscillation (NAO).
As indicated above, we are currently in an ENSO-neutral state and are expected to remain in neutral conditions or weak La Nina for the next six to nine months, leading to weather patterns dominated by the other intra-seasonal variations (MJO and NAO) which are highly variable and not easily predicted in larger time scales.
"Mean seasonal snowfall (November - March 1948 through 1993) in inches for Neutral years (top). Lower left map is the difference in snowfall between El Niño years and Neutral years. Lower right map is the difference in snowfall between La Niña years and Neutral years.
The above graphics from CPC and WFO Pueblo indicate a general trend of around average snow pack for South Central and Southeast Colorado in ENSO neutral years, with WFO Pueblo data supporting the highly variable aspect of snow pack in neutral years.
So, what does this mean for the upcoming winter season for South Central and Southeast Colorado?
In general, the warmer than average conditions across the entire CWA are supported by the fact that the average winter temperature departures from normal for the period of 1971-2000 are considerably cooler than those for the most recent 10-year average over much of the nation. Also supporting the warmer than normal forecast; especially across the eastern plains, is the fact that we have been in a generally positive NAO pattern. This pattern features a northern shift of the jet stream, keeping more westerly flow, with less troughiness and arctic outbreaks across the region.
The official CPC precipitation outlook across WFO Pueblo’s CWA is for “Equal Chances” of above, below or normal precipitation for the winter season. However, WFO Pueblo and CPC’s data do indicate we can generally expect around seasonal snow pack for the mountains across the CWA in an ENSO neutral phase. Across the Southeast Plains and high mountain valleys, the trend of more westerly flow would suggest drier than normal conditions. However, with fluctuating NAO and MJO phases, we can’t rule out occasional cutoff systems and upslope events which could lead to near normal precipitation. So, in general, we would tend to believe a near to slightly below normal forecast for precipitation across the Southeast Plains and high mountain valleys for the winter season.
To keep abreast of the current and forecast conditions of the NAO and MJO go to the following links.
Climate information for Alamosa, Colorado Springs and Pueblo can be found at:
Climate information for other areas of South Central and Southeast Colorado and Colorado can be found at:
Snowfall totals during ENSO neutral winters for Alamosa, Colorado Springs and Pueblo
From the charts below, you can see that Alamosa, Colorado Springs and Pueblo seem to exhibit the same variability in snowfall that the mountains do for ENSO neutral winters.
Alamosa received its least snowiest winter during a neutral year. But, it also saw its 3rd and 4th snowiest winters during neutral conditions. The neutral average at Alamosa ends up a little below the POR (Period of record) average.
Colorado Springs received its 1st, 2nd and 3rd lowest snowfall winters during neutral conditions. But, it also saw it's 3rd and 5th snowiest winters during neutral conditions. The neutral average for Colorado Springs ends up a little below the POR average.
Pueblo saw the 1st and 2nd snowiest winters, but a neutral winter also yielded the 4th and 5th lowest snowfall winters. The neutral average for Pueblo ends up a little above the POR average.