John Homenuk

NWS to investigate possible tornado in Queens last night

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A Tornado Warning was issued for Queens on Thursday evening shortly after 10:00pm, and the National Weather Service will head there this afternoon to investigate the possibility of tornado damage. Local terminal doppler radar showed the presence of a notable couplet, or signal for rotation, moving through College Point around 10:15pm.

The meteorology behind the potential tornado is quite interesting – not only in the fact that the warning was issued as rotation was developing, but in the fact that the heightened possibility of additional storms and potential tornadoes was evident several hours in advance.

Yesterday afternoon, a weak disturbance moved through the Northern Mid-Atlantic states and then northward towards New England. As it was doing so, multiple thunderstorms developed in New Jersey and then moved northward into Connecticut, prompting the issuance of Severe Thunderstorm Warnings in some locations in New England.

As the storms moved away from the NYC Area, however, they left behind “boundaries” – areas of disturbed weather, weak mesoscale wind shifts or areas of enhanced lift – that were, at the time, clearly visible on visible satellite imagery. In the below image, you can see the boundary angled from southwest to northeast in Northern New Jersey and towards New York City.

A remnant or preexisting boundary doesn’t guarantee that a tornado will occur, but it can enhance the possibility of additional storm development and, depending on its characteristics, enhance the potential for tornadogenesis if a strong storm does occur.It is not unreasonable to assume that is what occurred here.

As a small thunderstorm – a minisupercell – developed with a very warm, humid, nearly tropical airmass it moved northeastward towards Queens and began to develop enhanced rotation. On radar, meteorologists use storm relative velocity data to understand the wind components of storms. Here, we see red colors – which are winds moving away from the radar beam, and green colors – winds moving towards the radar beam.

When the two colors are directly next to each other with some speed (defined as a couplet) there is the possibility of rotation within the storm. On the below storm relative velocity imagery from the terminal doppler radar at JFK, we can clearly see the rotation area moving northward into Queens and towards College Point.

The National Weather Service will now head to Queens to try to clarify whether a tornado truly occurred or not. They will be looking for structural damage, tree damage, and patterns to the damage itself. One of the toughest determinations for meteorologists to make is whether or not the wind damage is from a tornado, or another force such as straight-line winds or a microburst.

With radar damage to as reference, however, a tornado confirmation appears likely in this case. Its strength will likely fall in the weaker category (EF0-EF1) with winds up to 110 mph, as evidenced by wind data on the terminal doppler radar.

Stay tuned for further information – and if you have photos or damage confirmation, please be sure to send it our way  (safely).