Hurricane Isaias threatens East Coast

  • Category 1 hurricane approaching Florida’s east coast
  • Second threat of landfall in the Carolinas
  • Impacts on New Jersey possible Monday PM through Tuesday PM
  • Up to 6″ of rain possible

Hurricane Isaias is churning through the Bahamas this morning, headed northwest on a track that will take the storm center just west of Grand Bahama and then approach of the east coast of Florida. Sustained winds as of the National Hurricane Center’s 11am update were 80mph. Frankly, the storm looks disorganized and unimpressive on satellite and radar at the moment. Isaias is struggling to maintain intensity in the face of moderate westerly wind shear. Some dry air entrainment on the southwest flank of the storm is hampering development as well. On the other hand, the storm is sitting in bathwater, which favors intensification. The Caribbean Sea surface temperatures are in the mid-80s, some of the warmest water in the entire Atlantic basin. Moderate wind sheer is expected to persist, but if Isaias were to find itself in a more favorable pocket of upper-level conditions, watch out.

What happens today, even just over the next few hours, will have major implications for timing and impacts on New Jersey. In general, Isaias is going to track northwest, gradually bend north, then curve northeast. This path puts the entire eastern seaboard on notice, with track possibilities ranging from just east of the Appalachians, to offshore, and any path in between. A weaker system will drift further west and landfall over Florida, while a stronger solution would keep Isaias off the coast, ultimately bending its path to the right and off the coast as it would approach New Jersey. Of course, with tropical systems, you don’t need to be in the path of the immediate storm center to feel significant impacts.

Regardless of the exact track, portions of New Jersey are in line for a significant rain event. The axis of heaviest rainfall will be determined by the specific track, but everyone in the state should prepare for the possibility of several inches of rain falling in a 12-18 hour stretch from Monday night to Tuesday night. Flash flooding, and flooding of urban/low-lying areas are primary concerns, with tidal flooding and gusty winds a secondary concern. An isolated tornado from embedded thunderstorms is possible, very much dependent on the final track of the storm center. Isaias will be a weakening tropical storm by the time it reaches our latitude, and so hurricane conditions are not expected. Similar to Tropical Storm Fay a few weeks ago, the primary impact here will be rainfall and flooding. Look for 2-4″ to be common, with some locations exceeding that. It is important to remember that if you didn’t see flooding with Fay, that doesn’t mean you won’t experience it with Isaias, or vice versa. The localized rainfall maxima across New Jersey will be a result of track, and embedded thunderstorms.

Stay tuned for frequent updates, as the movement and intensity fluctuation today will have significant effect on New Jersey’s weather on Tuesday.