After a rather snowy and bitterly cold first week of January, many folks are probably hoping for a January thaw...or at least some warmer weather. Good news appears to be on the horizon! Current model forecasts now indicate that a significant weather pattern change will occur next week, which will allow considerably warmer air to move back into the northern plains – including South Dakota and west-central Minnesota.
Below is an image showing the upper air pattern that was observed during the first week of January 2010. Note the strong trough of low pressure over central and eastern sections of the US. This produced a persistent north/northwesterly wind flow that allowed cold, arctic air to push southward from Canada.
Below is a model forecast valid next Tuesday - January 12th, 2010. Note the upper level trough of low pressure over the north-central US has been replaced by a ridge of high pressure which will promote more of a south/southwesterly wind flow over much of the central and western sections of the US. This southerly wind flow will gradually allow a warmer airmass to overspread the area.
Keep in mind that a majority of the upper Midwest still has a very robust snowpack (snow depths of 10"-30"). This deep snowpack will suppress the amount of warming that will take place at the surface. Even so, temperatures are expected to rise at or above seasonal normals throughout much of next week.
Below are a series of graphics depicting the forecast high temperatures next Tuesday and Wednesday. Not exactly Bermuda shorts weather – but milder nonetheless! The good news is that milder temperatures are likely to persist through at least the the middle of the month.
Mike Fowle - SOO