Dylan R. Card, Kristen L. Corbosiero, Ross A. Lazear, Hugh Johnson, and Michael Augustyniak
Abstract:
The unique terrain found in eastern New York State plays a pivotal role in both the warm- and cold-season weather of the region. The west to east Mohawk and north to south Hudson River valleys intersect in the Capital Region of New York, and can result in localized flow channeling and boundary layer convergence. Several previous case studies have documented the important role of Mohawk–Hudson convergence (MHC) in modulating the low-level wind profile in cases of warm-season severe weather. However, a comprehensive, composite and case study analysis of these events, which pose a significant challenge to local forecasters, has not been previously published. Composite analysis shows that warm-season MHC precipitation events are characterized by weak warm-air advection and geostrophic southwesterly flow that advects low-level, warm, moist air up the Hudson River valley and westerly flow down the Mohawk River valley, leading to increased instability. Cold-season MHC events are characterized by weak cold-air advection from the northwesterly geostrophic flow which allows for surface flow to be channeled westerly down the Mohawk Valley and northerly flow to be channeled down the Hudson Valley. As well as remnant boundary layer moisture in conjunction with cyclones departing off the coast of New England. On this no While most MHC events do not produce significant sensible weather, they can occasionally be impactful if they occur with little warning and/or during peak travel times. Cold, MHC precipitation can result in persistent moderate to heavy snow in the wake of a departing low pressure, whereas warm MHC cases often initiate an unexpected thunderstorm close to Albany International Airport. The case of 2 January 2008 was a significant cold season event which caused heavy snow in the Capital District Region effecting travel at Albany International Airport.
Presentation: 42nd Northeast Storms Conference