Ramblings of a Graduate Student

Last night I mentioned that the models were indicating that the warm up that portions of the southern United States has experienced over the last day or so was going to be relatively short lived.  Model forecasts have been persistent in bringing south cold air was pooling in northern Canada.  Tonight, I thought I would show you from where the cold air was originating.  The image above is a hemispheric plot.  The United States is in the bottom center and Europe/Asia in on the top center.  The white circle in the very middle of the image is the North Pole.  The black lines represent surface pressure features and the colored shading is the height at which the 500 mb pressure surface would be found.  (The 500 mb pressure surface could be thought of as the middle of the troposphere.)

So what does all this mean?  Well, in the image above, the cooler (blue) colors tend to be associated with cooler atmospheric temperatures and warmer (red) colors tend to be associated with warmer atmospheric temperatures.  Notice the warmer colors over the western portion of North America.  This is because of the ridge (upper-level high) over the area.  The warmer temperatures throughout the atmosphere associated with this upper-level high have wreaked havoc with the Winter Olympics.

Of interest for the upcoming week is the pocket of cooler colors in central Canada.  If one were to look at a loop of this map, it would be readily apparent that the colors (and atmospheric temperatures as well) have been trending even cooler and expanding in central Canada.  Over the next few days this pocket of cooler atmospheric air will surge south into the United States.  This will effectively return much of the southern United States back to below average temperatures.

And, as the title alludes to, the potential exists for another southern United States snow storm by mid-week.  With the cold air in place, an upper-level low will move from the eastern Pacific Ocean into southern California then into Texas.  Depending on the exact track of this upper-low, snow will be possible in portions of the southern plains.

Oh, and the models have consistently taken this potential mid-week southern plains snow storm and developed a Nor’easter by late next week.  It looks like more snow will be possible for areas along the east coast that have already seen a lot of snow this winter.  People from Washington D.C. to Boston will need to watch the forecast closely over the coming week.