This upcoming storm is what is known as a southwest flow event (SWFE). A southwest flow event is characterized by southwest winds within the 800-500mb layer (~6,000 feet to 18,000 feet above the ground) which in turn is associated with warm air advection. Hence, precipitation ranging from snow to sleet/freezing rain, and rain. These setups are typically characterized by a very brief period of heavy precipitation (associated with the warm air advection). Depending on the profile of the atmosphere, this can often be a period of snow.
Snow should begin working into the state Monday evening as stronger low-level rising motion associated with a push of warm-air advection arrives:
As warmer air arrives snow will begin to transition and this is where things get interesting. Along the immediate shoreline snow quickly changes to sleet and rain (in fact, along the immediate shore precipitation may even begin as sleet). Farther inland, however, the surface will be much slower to warm. This results in more sleet and perhaps more freezing rain...and this is where it gets interesting. Are we going to see more sleet or more freezing rain?
Forecast soundings from the NAM and GFS at Windsor Locks, CT for Tuesday at noon both suggest freezing rain will still be falling (will just show the NAM do to time constraints):
What to Expect:
- Snow begins breaking out between 5:00 PM and 8:00 PM Monday evening and will quickly become moderate to even heavy. Snow persist for 4-5 hours (much less along the shoreline).
- Snow begins to transition to a wintry mix during the late evening or early overnight (closer to early evening along the immediate shoreline)
- Sleet and freezing rain persist well through Tuesday morning and into the afternoon before perhaps ending as some rain.
- Significant freezing rain is not expected, however, isolated power outages/tree damage may result and this will impact travel.
Below is what I am thinking:
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