Upcoming Winter Storm Chances
by Kelly Smith, Meteorologist
December 13, 2011 12:35 PM
A Winter Storm is approaching the Sioux Empire Tuesday and Wednesday, here is what you can expect.An approaching Winter Storm has the opportunity to make a mess out of the Sioux Empire Tuesday evening and Wednesday. Warm, moist air is being funneled into the Sioux Empire thanks in part by southeasterly winds. Low-level moisture has created cloud cover and fog over the last couple of days, acting like a blanket and keeping temperatures fairly warm, especially in southeast South Dakota. The above average temperatures are making this particular storm system difficult to forecast.Temperatures are within a couple of degrees of freezing and are forecasted to fluctuate above and below freezing over the next 48 hours as this next storm system blows through. Temperature fluctuations make forecasting the type of precipitation that falls very tough. The difference between a couple of degrees in a situation like this means night and day. It is highly plausible that many areas will see a mixed bag of sorts. With temperatures changing throughout the evening Tuesday and daytime Wednesday, there will be many changes in precipitation types.
(Tuesday afternoon and early evening)Any precipitation that falls Tuesday early evening west of I-29 should fall as a rain/snow mix. Southeast of Sioux Falls, where temperatures will be above freezing will likely see any precipitation that falls as rain.
(Tuesday Night)Tuesday overnight, poses a different challenge all together. Temperatures are more likely to be much farther apart, with cooler temperature to the northwest and warmer temperatures to the southeast. A greater probability of rain will exist in the southeast overnight.
(Wednesday)Wednesday morning and afternoon will remain warmer, but a quick cooling of temperatures as a cold front moves through will likely cause a larger area of frozen precipitation, especially in late afternoon and early evening.Much cooler air will filter in Wednesday night along with a brisk northwest wind. Any standing rainfall or wet roads will likely freeze creating icy conditions for Thursday morning and afternoon.
(Adonis Futurecast Temperatures)Futurecast Temperatures show just how difficult the forecast is with temperatures so close to freezing.
(Adonis Futurecast Surface Temperatures)Temperatures will continue to rise Wednesday afternoon ahead of the cold front that will arrive Wednesday evening and cool temperatures down for the end of the work week.This storm in unlikely to bring snowfall accumulations over a half inch, however we are entering into an active pattern over the next couple of weeks and there are a couple of storms that will need to be monitored prior to Christmas. NOAA has put together a map of the probability of a White Christmas in the mean time.