MESOSCALE DISCUSSIONS

INTRODUCTION


Winter weather is a topic I love talking about.  It comes in so many forms, from snow to sleet to what people think is the most dangerous, freezing rain.  I live in western Pennsylvania; therefore, I know firsthand that when a winter storm is forecast, everyone wants to know exactly what kind of precipitation they're going to get and how much.  One of the best places to find out this information is from the Storm Prediction Center (SPC).  When winter weather, or severe weather of any kind, is ready to strike, the SPC issues a mesoscale discussion (MD) for the areas that are going to be affected, however, these discussions can be difficult for most people to interpret, due to the advanced terminology.  So, in this project, I'm going to thoroughly translate a MD that was issued on January 8, 2007 which is outlined to the right.
                                                                                                      On January 8, 2007, the SPC issued a MD outlining an area where heavy snow and freezing rain
                                                                                                                                was expected.  Here is the corresponding text further explaining the situation, courtesy of SPC.

The beginning of January 2007 was a relatively mild time for the Northeast; therefore, instead of a straight snowstorm, residents of northern New York and northern Vermont were expecting a mix of snow and freezing rain for areas only above 1,000 feet.  This surface analysis from the HPC from January 8 shows a high pressure system moving off the New England coast, while at the same time a low pressure system was moving up the Ohio valley.  The clockwise flow around the high worked in tandem with the counterclockwise flow around the low to produce a strong southerly flow over the cold dry air at the surface.  Now that forecasters at the SPC saw a few of the right ingredients in place for a winter storm, it was time to issue a MD.  Now, let's further examine it.

                                                                                             

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