November 2007 Saint Cloud Weather Summary

    Saint Cloud had taken major strides to erase the growing season rainfall shortage in September and October. However, the dryness dominated November once again. According to the statistics from the St. Cloud Regional Airport, only 0.01 inch of precipitation fell in November 2007. This was 1.53 inches below normal for the month. November 2007 was only the fifth November out of 114 in St. Cloud precipitation records with 0.01 inch or less record and the first since 1941. There have only been 17 months out of the 1368 recorded months with either zero or 0.01 inch of rain.

The low rainfall undid much of the catching up done the past two months. There had been a total of 8.29 inches of rain between September 6 and October 19, double the normal rainfall. That allowed St. Cloud's growing season rainfall deficit to be cut from over 6 inches to less than 2 inches (see the final growing season drought summary from the Minnesota State Climatology Office). However, between October 20 and the end of November, only that 0.01 inch of rain fell, pushing the April-November rainfall deficit to 3.66 inches. Since water usage is so low during November (less evaporation, plants take in less), we lost a good opportunity to make further inroads to the deficit. Instead, moisture conditions have been literally frozen until spring since the cold weather at the end of the month has caused the ground to freeze.

There were two different weather patterns responsible for the dryness. Much of November was dominated by steering wind flow from west to east across the Northern Tier of states. There were a lot of fast-moving storms in this pattern, but they only had dry air with which to work. An active southern US storm track made sure that all of the moisture got into weather systems to our south, but cut off the moisture before it could get here. In the latter part of November, the split storm tracks united, but in a northwest-to-southeast direction, blowing from the Yukon Territories and the Arctic Ocean into Minnesota. That flow of cold air was even more dry than what we had from late October through mid-November.

It is ironic to be talking so much about being short of water on a day when between 3/4 inch and an inch of liquid will fall in the form of snow. For this December 1 weather system, the two storm tracks are working together to allow substantial middle atmosphere moisture from the Pacific and more moist air from the Southern Plains to allow heavy precipitation totals. The snowmelt will eventually help to recharge area lakes and rivers, but the frozen ground will stop it from helping soil moisture. We will now have to wait for spring rains after the ground has thawed to do that job.

The total precipitation during the Fall 2007 (Sept 1-Nov 30) was 8.25 inches, still 1.54 inches above normal, but it was a lot closer to normal, thanks to the dry last 6 weeks.

Temperature-wise, November 2007 finished off a very mild fall. The average (Sept 1-Nov 30) fall St. Cloud temperature was 47.7°F, 3.9°F warmer than normal. This was only 0.9°F short of cracking one of St. Cloud 10 warmest falls, but November 2007 only ranks as the 23rd warmest fall in St. Cloud records. The month that cost 2007 a top 10 finish was November. While last month was milder than normal, but not as mild as recent years. The average November 2007 temperature at the St. Cloud Airport was 31.2°F, 2.4°F above normal. However, this November was cooler than each of the past 3 Novembers and 7 of the past 10 Novembers. That's mainly because recent Novembers have been so mild, including the warmest November (2001) and the 5th warmest November (1999). This November was on pace to continue recent warmth. As late as November 21, the November average temperature was 36.1°F, warm enough to tie November 1917 for the 10th warmest November. However, the last 9 days of the month averaged 19.8°F, typical of December 4. Three of the last four days of November had high temperatures of 15-18°F typical of mid-January. We are getting a temporary reprieve from the coldest weather over this weekend, but the deep snow cover will make it harder to warm up during the next week because fresh snow reflects 70-90% of the sun's energy back to space. Also, despite milder air, the weather pattern remains a cold one with air flow continuing out of the Yukon Territories. We will probably spend most of the first half of December with no better than normal temperatures with many days of below normal temperatures.

With the dry conditions, snowfall was irrelevant...until the calendar changed to December. Only 0.5 inch of snow fell in November 2007 and it took three individual light snows to build the total to 0.5 inch. This was well short of the normal of 8.8 inches in November. For the cold season, St. Cloud had only 0.5 of the normal 9.7 inches of snow. However, conditions have radically changed on December 1, but that's a story for another month.