Winter weather alerts are in place for 9 million Americans. December 13, 2020, 11:51 AM • 4 Minute Read Share to Facebook Today South. The low pressure wave is expected to ride the jet stream from the southern Rockies to the southeast. It is accompanied by rain and wet snow. Rain and mountain snow will continue in some parts of northwestern California until Monday morning. Northern Rockies. Winter weather alerts are available to 9 million Americans in the Atlantic, Rockies and Central Plains. Winter weather warnings are in place for 9 million Americans in the plains, the Rockies and the Central Plains. Early morning snowfall is expected on Monday and Sierra Nevada will see 6 to 10 inches of snow at high altitudes, while surrounding areas will see a gene roll 3 to 6 inches. Texas will see snowfall in the northern part of the storm Sunday morning in northern Oklahoma, northern Arkansas and southern Missouri. The storm ends moving south very quickly overnight Monday morning Those on the East Coast and the Appalachians may have been looking for a little snow for a morning trek from Pennsylvania to Virginia. Elsewhere, however, it often looks like rain. While it is possible to mix a few wet snowflakes, it does not seem promising to see if there is any accumulation east of I-81. There is still uncertainty about this forecast but we are closely monitoring the possible latest guidelines for winter storms off the east coast later this week. Below are displays of two major computer prediction models. You will notice that the impacts are very different in both situations, so it is very soon to make a definite call as to who exactly gets the snow or not. The European model shows a slightly warmer solution, with very low snow accumulation levels entering from Washington, D.C. via central New Jersey and Connecticut. The European model shows low snowfall levels from Washington, D.C. via central New Jersey and Connecticut with a slightly sharper cut. If this case goes out, more concentrations will be west of I-95. This particular model also supports more rainfall for NYC and Washington, which may reduce the amount of snow, but also result in a layer of snow on the outer surfaces. The American (GFS) model shows a lower cooling solution. This will allow for an ice event in Washington, DC, Philadelphia and New York City. The American (GFS) model shows a lower cooling solution. This will allow for an ice event in Washington, DC, Philadelphia and New York City. Again: the differences in computer guidance are very pronounced at this time. The vulnerabilities are minimal and depend heavily on the proper formation and location of the system. As we get closer to the event we will have more confidence about specific impacts and will update accordingly.
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