An Odd December Transitioning into a Cooler New Year's
by Angela Schilling, Meteorologist
December 28, 2011 8:55 AM
The New Year is just around the corner and we have seen our fair share of weather. This past month has been one for the record books, but this year it is not because of record snowfall amounts or wind chills but rather for the insanely warm weather we’ve been experiencing. We’ve been in a drought for the last several months and the pattern looks to continue at least through this upcoming weekend.
Highs on Tuesday were in the mid to upper 30’s and compared to where we have been that was considered a cool down, now compare the 30's to last winter and that would have been considered a warm up. Over the last several years we’ve seen highs fluctuate up and down over time. The graphic below shows the number of days we saw temperatures below average for the month of December, keep in mind highs are typically in the 20’s for the start of the winter, if not a shade colder.
We’re also behind on snowfall amounts this year. Typically our first snowfall is in the later half of October, and we didn’t get anything in Sioux Falls until November 19th, where we mainly saw freezing drizzle in Sioux Falls. We typically get around 8 inches of snow during the month of December, but this year we have only received .3 inches of snow so far, not even an inch!
We are underneath such a dry air mass that when lows move through the main thing they do is just kick up our winds, which is exactly what is going to happen both Thursday and New Years. A couple areas of low pressure will be moving through the Northern Plains over the next couple of days, the first one arrives Wednesday night and the second Thursday evening. As we get some southerly flow both today and Thursday we might get just enough moisture to squeeze out some light rain in northeastern South Dakota Thursday evening. The dynamics are there for rain; it is the moisture, which is lacking. Cold front swings through Saturday, behind the front our winds will rocket out of the northwest at around 20 to 40 miles per hour, sustained. As far as temperatures next week, the models are very scattered with some showing temperatures in the 30’s and others are quite a bit colder.
Surface temperatures for Wednesday afternoon...mid 40's to the lower 50's, west
500mb or halfway up through the atmosphere...low moves southeast, want to be ahead
of the low to get rain or snow...keep in mind this is for Thursday evening. The bright
red color represents vorticitiy or spin of the atmosphere.
Also for Thursday evening, bright blue represents higher amounts of relative humidity,
notice where the moisture is...in the northeast.