Author: Emily Berndt
The February 8-9, 2013, Northeast Blizzard did indeed produce near hurricane force wind gusts. In the original blog post on February 8th, featuring this storm, I noted the presence of stratospheric air on the RGB Air Mass Imagery and high concentrations of ozone present as seen by AIRS. The presence of these signatures was a good indicator that a stratospheric intrusion was present and could lead to high surface wind gusts. The graphic below from the NWS Eastern Region Headquarters shows a summary of the highest wind gusts during the event. Note that winds greater than 74 mph are equivalent to a category 1 Hurricane. Parts of Virginia, Massachusetts, Rhode Island, Connecticut, and Maine were impacted by hurricane force wind gusts.
Further investigation of ozone with the Ozone Mapping and Profiler Suite (OMPS) part of the new Suomi National Polar-orbiting Partnership (NPP) Mission provides a snapshot of global daily ozone concentration. Click on the image below to see the animation of Daily Ozone from February 6th-9th. The animation below shows ozone concentrations greater than 300 Dobson Units stretching south over the Northeast states. The OMPS Daily ozone product is valuable in showing the daily progression of higher concentrations of ozone associated with stratospheric intrusions. How does this region of higher ozone values compare to RGB Air Mass Imagery?
The MODIS RGB Air Mass Imagery helps confirm the presence of warm, dry, stratospheric air drawn into the storm. The darker orange colors represent the presence of stratospheric air. Comparing the position of the ozone-rich stratospheric air in the animation (click on the image) with the location of the warm, dry stratospheric air on the MODIS RGB Air Mass Imagery confirms there was higher momentum stratospheric air available to be drawn into the storm and transported to the surface to create hurricane force wind gusts. Of course further investigation of cross sections is necessary to further establish the link between the stratosphere and the high winds that were created during this event.
So what can we say about this next storm posed to impact the Northeast today through Friday. The National Weather Service is anticipating gusts up to 45-55 mph as the storm intensifies off the coast. A current surface analysis shows there are wind gusts upward of 45 knots (52 mph) along the coastline. An Aqua MODIS RGB Air Mass image from 0709 UTC this morning shows a broad area of orange covering the southeastern US. This warm, dry stratospheric air is being drawn into the storm. The most current OMPS Daily ozone image again shows higher values of ozone concentrated over the same area as the warm, dry stratospheric air. Over the next few days, I’ll be watching the progression of OMPS ozone and stratospheric air on the RGB Air Mass Imagery!