A Qualitative Analysis on the Role of Convective Latent Heat Release in the Blizzard of 2017 Track

A significant mid-latitude synoptic cyclone impacted much of the Northeast from March 13^th to March 15^th, 2017. Locations across interior Pennsylvania through Upstate New York received over three feet of snow. With the heaviest snow northwest of I-95, this spared many of the population centers in the Northeast from the highest snow totals. Model forecasts seventy-two hours in advance did not capture how far northwest the highest snow totals would progress. Ahead of the progression of this storm, convection off of the Southeast coast was depicted on model guidance, and later, was observed. This convection stemmed from another disturbance that had progressed through the United States a couple days earlier. Here, a link between the modeled 500 hPa vorticity signature associated with this convection off of the Southeast coast beginning with the March 9^th, 2017 00 UTC Global Forecast System (GFS) run, and the resultant storm track is analyzed. The modeled GFS 500 hPa vorticity forecasts are centered on March 14^th, 2017 at 00 UTC. The GFS Quantitative Precipitation Forecast (QPF) for both New York City, New York and Harrisburg, Pennsylvania are also analyzed for 21 GFS runs, beginning with the March 9^th, 2017 00 UTC run. 500 hPa height differences are also considered between five runs of the GFS and the March 14^th, 2017 00 UTC initialization. The results show that a significant portion of the QPF variability observed with the GFS runs can be explained by the run-to-run variability in the evolution of the 500 hPa vorticity associated with this convection off of the Southeast coast. A qualitative link between latent heat release, height rises along the East coast, and the resultant storm track is analyzed. Future research should aim to analyze this link from a quantitative perspective.