The Atlantic basin remains active with two tropical cyclones. Hurricane Grace is strengthening over the Bay of Campeche, and is likely to make landfall in northern Veracruz, Mexico early Saturday morning. In addition, Tropical Storm Henri is still expected to become a hurricane, and has a chance to become the first fully tropical hurricane to make landfall in the New England region since Hurricane Bob in 1991.

As of 4:00 p.m. CDT (5:00 p.m. EDT) Friday, Hurricane Grace was centered near 20.5°N 95.1°W, and was moving westward at about 10 mph. Maximum sustained winds were 80 knots (90 mph), with an estimated minimum pressure of 979 mb. Grace, the strongest Atlantic hurricane so far this year, is strengthening over the Bay of Campeche, and is expected to make landfall in the Mexican state of Veracruz early Saturday morning. With warm sea surface temperatures near 30°C (86°F), light to moderate vertical wind shear, and an inner core, Grace appears likely to intensify into a Category 2 hurricane prior to making landfall. Although unlikely, there is a small chance Grace could reach major hurricane intensity if a period of rapid intensification occurs in the final hours before Grace makes landfall in 9-12 hours. An Air Force Hurricane Hunter aircraft is currently en route to investigate Grace this evening. A Hurricane Warning is currently in effect from the coast of mainland Mexico from Puerto Veracruz to Cabo Rojo, while a Tropical Storm Warning is currently in effect from the coast of mainland Mexico from north of Cabo Rojo to Barra del Tordo. Grace is expected to produce hurricane conditions in the hurricane warned area tonight, with potential for 4-6 feet of storm surge, 6-12 inches of rainfall with higher isolated totals, and mudslides. Grace should weaken quickly after moving inland over the mountainous terrain of central Mexico, and the cyclone’s circulation will likely dissipate over west-central Mexico late Saturday or early Sunday as it drifts west-southwestward. However, Grace’s mid-level remnants are likely to contribute to the development of a new tropical cyclone over the eastern Pacific, where the National Hurricane Center (NHC) gives an 80% chance of development within five days.

As of 5:00 p.m. EDT Friday, Tropical Storm Henri was centered near 31.2°N 73.9°W, and was moving north-northwestward at about 7 mph. Maximum sustained winds were 60 knots (70 mph), with an estimated minimum pressure of 994 mb. Although Henri is close to becoming a hurricane, the low-level circulation remains on the northern edge of the convective mass, indicating continued vertical shear. However, the shear is expected to relax tonight, which will likely allow Henri to become a hurricane. Intensification may be a bit limited for the next 6-12 hours as the low and mid-level centers appear to be misaligned, but for much of the day on Saturday, the environment will be favorable for intensification of Henri as it moves northward to north-northeastward. In about 36 hours or so, Henri is expected to move north of the 26°C (78.8°F) isotherm, which will likely prevent any additional intensification and likely cause the cyclone to weaken. The current NHC forecast predicts Henri will peak as a Category 1 hurricane with maximum sustained winds near 85 mph. This forecast seems reasonable, since Henri has been unable to develop an inner core so far due to persistent shear, and will likely not have enough time to strengthen to become a powerful hurricane. Regardless, Henri’s threat to New England has significantly increased, and there is now good model agreement that the cyclone will make landfall on Sunday. A Hurricane Warning is currently in effect for much of Long Island, as well as Connecticut from New Haven eastward to western Rhode Island. A Hurricane Watch is currently in effect from Watch Hill, Rhode Island to Sagamore Beach Massachusetts, as well as Nantucket, Martha’s Vineyard, and Block Island.

A Tropical Storm Warning is currently in effect for Port Jefferson Harbor to west of New Haven Connecticut, as well as the south shore of Long Island from west of Fire Island Inlet to East Rockaway Inlet. A Tropical Storm Watch is currently in effect for the east-central coast of New Jersey, as well as New York City. A Storm Surge Warning is currently in effect for the south shore of Long Island from Mastic Beach to Montauk Point, the north shore of Long Island from Oyster Bay to Montauk Point, from Greenwich, Connecticut to Chatham, Massachusetts, including Nantucket, Martha’s Vineyard, and Block Island. This is not a region that typically sees fully tropical hurricane landfalls, with the most recent New England hurricane landfall being Bob in 1991. Interests in this region should monitor Henri closely, as we should have a clearer picture of the exact track tomorrow.