On Wednesday morning, NOAA and the Air Force had aircraft flying through Grace, and found it had reached hurricane intensity, making it the season's second hurricane (Elsa was the first, way back on July 2). It just passed over the Cayman Islands and will reach the Yucatan Peninsula by early Thursday morning. The forecast is confidently for it to continue the westward track and make a second landfall on Mexico on Friday night.
As I pointed out previously, the ocean heat content (an integrated measure of the ocean's temperature, not just the surface) is extremely high over the western Caribbean, so Grace will access that today. Then, land interaction with the Yucatan will weaken it, and the ocean heat content is still high in the southern Gulf of Mexico, but not nearly as high. However, the surface temperature is very high and will be plenty to fuel reintensification.
 |
| Current map of ocean heat content (left) and sea surface temperature (right). Daily images always available at http://bmcnoldy.rsmas.miami.edu/tropics/sectors/. |
Moving on to Henri, it is approaching hurricane intensity, and is also starting to look a little more problematic for the northeast U.S. in the coming days. It's making a slow loop around Bermuda, but by the time it's on the west side of the island, it could also be much stronger, and much closer, to the New England region.
In terms of model guidance, there is reason for some concern in the Sunday-Monday timeframe. The GFS ensemble has had consistency in showing some members not only getting close to the U.S. coast, but actually making landfall as a hurricane. Other deterministic dynamical models have also shown this, so it should be taken seriously -- it's only 4-5 days out.
Looking further east, there is some model guidance indicating that a wave just exiting western Africa could develop in the coming 5-7 days. The next name on the list is Ida. (Ida was introduced to the list in 2009, after Isabel was retired from the 2003 season).
With Grace now a hurricane, that is 8 days ahead of the average date of second hurricane formation, which is August 26th.
Dear Brian, I would like to cite this information on last 30-years average dates of hurricane formation. How can I cite it? Thank you.
ReplyDeleteThat's a good question... either the URL of the blog post, or it's also on Twitter (https://twitter.com/BMcNoldy/status/1427970313501904900).
Delete