The last week of weather across the US out into the central Atlantic has been rather busy. Earlier in the week, a low in the North Atlantic bottomed out at 934 mb and produced hurricane-force winds to 65-75 kt.
Prior to the surface analysis above, ASCAT showed the hurricane-force winds in the west to southwest quadrants.
That area of winds coincides with a strong stratospheric intrusion above 700 mb that wraps around the southwest and south quadrants. How do we know it’s stratospheric air? The ozone anomaly image from the NOAA Unique Combined Atmospheric Profiles (NUCAPS) shows the elevated ozone anomalies in the same general location as the strong winds.
Later in the week, another well-forecasted hurricane-force low rapidly intensified farther south with peak ASCAT winds of 65-75 kt, though higher winds may have occurred prior to the occlusion between overpass times.
The four day animation of the Air Mass RGB from GOES-16 (East) shows both storms with a strong signal for stratospheric drying (oranges/reds moving towards the center of each storm) which coincides with the strongest winds. Note how the second storm rounds the ridge after delivering wintry weather in the Mid-Atlantic and exhibits Shapiro-Keyser characteristics (note the system riding the northern edge of the baroclinic zone).
Unfortunately, we didn’t get an ozone overpass during the strongest winds. The OPC surface analysis below depicts a 959 mb low around the time of the ASCAT pass, yet the storm has continued to deepen today (02/24/19) to around 948 mb.
The active pattern looks to continue into the next week, but farther west as blocking strengthens in the eastern Atlantic.
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