Although many forecast models seemed to consistently steer the powerful category 4 hurricane into the US mainland luckily this did not come to fruition. That being said the east coast of the United States still was influenced by Joaquin in the form of historic flooding as well as coastal flooding. The major meteorological players in this scenario were the hurricane itself and areas of High Pressure to the north and east; it was the forecasted movement of these features that caused dramatic differences amongst the forecast models. Ultimately, the storm ended up maneuvering further south and deeper into the Bahamas than initially anticipated and then the storm moved further out to sea sparing the East Coast of a direct impact.
Figure 1 www.wpc.ncep.noaa Showing surface analysis with Joaquin to the southeast and High pressure to the North and East (not shown) the pressure differences between these systems would ultimately create the onshore flow responsible for coastal flooding.
Figure 2 www.nasa.gov View of Joaquin form the ISS
Nonetheless, there were affects from the storm; the pressure gradient created strong onshore winds that pushed and piled water towards the east coast and led to coastal flooding concerns that were exacerbated by the presence of large waves from Joaquin. The updated Verisk Insurance Solutions’ wind algorithm highlighted the onshore winds up and down the East Coast. Looking at the image below (Figure 3) you can see an area of stronger winds along the eastern seaboard that contributed to higher tides and coastal flooding.
Figure 3 Benchmark Web Wind map utilizing Updated Wind Algorithm portraying strong winds along the coast that contributed to coastal flooding.
Another unfortunate outcome of the onshore flow was the channeling of deep moisture from Joaquin and the tropics that led to historic amounts of rain in the southeast, which caused much destruction. This stresses the connected nature of meteorological events in that even a storm far out to sea was able to impact a large area very far away from its center. The fact that our proprietary wind algorithm handled this event so well comes as no surprise since it uses cutting edge model input, real world measurements, and is carefully verified with industry claims data. This is just one of the many examples of our wind algorithm proving itself in real world situations that in turn provides our customers the ability to shorten claims time, confidently make decisions on claims, and receive easy to understand trustworthy data. Our wind algorithm measures the speed and duration of straight line wind such as, thunderstorms, derechos, Santa Ana winds, micro bursts and other non-tornadic wind events. Verisk also provides a suite of products that handle tropical events as well as tornadic events (Respond™.) With such a trusted name and product, when a wind report or map is ordered it’s not only trustworthy and easy it’s a (pardon the bad pun) wind wind situation.
Figure 4 Verisk Analysis of the historic rainfall in SC