The extensive and high magnitude drought that has afflicted various parts of the U.S. continues late into the 2012 calendar year. These conditions will only be alleviated if significant changes in precipitation patterns occur in 2013. I wanted to do a quick post on this topic as a significant winter storm is making its way across the country so I can do a before/after look next week. This storm will largely impact the inter-mountain west as some places receive 1 to 3 feet of snow. Some slight relief will also be felt across the High and northern Great Plains as a blizzard impacts the region today and tomorrow. Here are drought conditions in the West as of last week:
The percent area values haven’t changed too much since early July, but the specific areas impacted have moved around somewhat in response to weather systems in the intervening time period. The mountains in this region are experiencing their own drought, just as the inter-mountain plateaus are.
Look at the High Plains, which saw drought conditions expand and worsen quickly this summer and fall:
Only a tiny stretch of North Dakota is not currently experiencing any level of drought. A majority of the High Plains is actually in Extreme drought (red or dark brown). These conditions developed rapidly north of 40 degrees latitude (northern border of Kansas) this year. These locations will benefit somewhat from winter snow, but need spring and summer rain to really get rid of this drought.
So far in the month of December, the average temperature for Denver, CO is 37.3°F, which is 7.1°F above normal. The next week or so will include near and below average temperatures, which will reduce this anomaly. With only 12 days left in the month however, December will likely be another month in 2012 that higher than normal temperatures were the rule. Denver’s average November temperature was 43.5°F, 5.2°F above normal. October bucked the 2012 trend with a -1.9°F anomaly (49.0°F average). September was 2.9°F above normal (66.3°F average).
In November, there was a -0.34″ precipitation deficit from normal. October was slightly more wet than normal: +0.20″ (1.22″ total), as was September: +1.99″ (2.95″ total). This is largely why drought severity in the Denver area is only moderate and not severe or extreme. Note that most of the positive precipitation anomaly in September was the result of one storm which rained overnight on the 25th into the 26th (1.95″). Without this storm, local drought conditions would likely be worse.
Precipitation for 2012 remain anomalously low. The NWS recorded 9.89″ of precipitation so far this year, compared to a normal of 14.17″ (-4.28″ or 30% deficit). In contrast, 2011 was a wet year with 17.31″ through Dec. 31st. We all hope 2013 returns to normal or above average conditions so that this drought ends.
Data from Denver-Boulder NWS Office.