Daily Archives: September 2, 2016

NYC Labor Day Weekend Weather – TS Hermine – Sep 2, 2016

I wrote that I would not be posting any updates while on vacation unless there were to be a special event that warranted it. Well, the likely approach of the remnants of Tropical Storm Hermine into the offshore waters in our region certainly warrants this special update. As of now, it appears that Labor Day itself will be the only day when we could see significant impacts from this storm, but this could change. I will likely have another update Sunday.

Rest of today – sunny, and pleasant with a high in the low-80s. This will be by far the best day of the long weekend.

Saturday – increasing clouds, high temperature around 80ºF.

Sunday – mostly cloudy, with chances for rain increasing in the afternoon. Cool, with highs only in the mid-upper 70s.

Labor Day (Monday) – tropical storm conditions possible, strong and gusty winds, and possible periods of heavy rain, especially in coastal areas. Dangerous rip currents at the beaches, as well as moderate to major coastal flooding. Mostly cloudy otherwise with high temperatures in the upper-70s.

Tropical Storm Hermine this morning
Tropical Storm Hermine this morning

Tuesday – with the remnants of Hermine currently forecast to linger off of the coast of the Northeast, we could see another day of possible tropical storm conditions. Warmer, with high temperatures in the low-80s.

Tropical Storm Hermine’s Forecast

Since the inception of Hermine as a tropical wave off the coast of West Africa, forecasters have had difficulty in accurately capturing the track and intensity of this storm. Its approach towards our region is no different. The forecast is complicated by the fact that Hermine will be completing a process of extratropical transition. A complex set of interactions between it and a frontal boundary adds a high degree of uncertainty towards the late period of this forecast.

Forecast Track

As of this morning, the National Hurricane Center’s official 5 day forecast called for Hermine to continue tracking rapidly northeast just inland of the Southeast coast as it initially interacts with a frontal boundary in its vicinity. During this period, it is expected to weaken, but by Saturday evening, it is expected to re-emerge over open water off the North Carolina Coast. At this point, Hermine is expected to have completed extratropical transition. It will begin another interaction with a baroclinic frontal zone, which is expected to significantly slow its forward progress down. This slowing will likely also lead to the storm erratically meandering off the Northeast coast, possibly doing a loop.

093924W5_NL_sm

at201609_model
Some major forecast model’s current output for Hermine
at201609_ensmodel
GFS ensemble models (spaghetti models), white denotes the consensus track

Intensity Forecast

During the period that the storm is over land, it will weaken continuously. However, by Saturday evening, when it is expected to re-emerge over open water, and complete extratropical transition, it will gain in strength. The extratropical transition will impart energy from baroclinic forces (interactions between airmasses of differing pressures), and the storm is expected to re-intensify into a strong extratropical storm with sustained winds of 60-65mph.

Impacts

The intensity and location of these impacts will depend greatly on the eventual track for this storm.

Tropical storm watches are in effect for the entire New Jersey coast. Heavy rain in coastal areas. Strong sustained winds, winds gusting in excess of 50mph in some coastal areas. Beach erosion along with coastal flooding, possibly for an extended period of time. High surf and dangerous rip currents.