Tropical Storm Harvey made landfall near Cameron, Louisiana, early Wednesday morning, and has since weakened to a tropical depression inland. As Harvey made landfall, a new tropical storm formed in the eastern Atlantic, named Irma. Irma is likely to strengthen into a hurricane tomorrow and is likely to become the second major hurricane of the season by early next week in the tropical Atlantic, which has lacked strong hurricanes in recent years. In the Eastern Pacific, Tropical Storm Lidia has formed, and poses a threat to Baja California.

Harvey weakens to a tropical depression, likely to become a remnant low on Friday

Tropical Depression Harvey made landfall in Southwestern Louisiana early this morning, and has since weakened to a tropical depression as it has moved inland. As of 10:00 p.m. CDT (11:00 p.m. EDT), Tropical Depression Harvey was centered near 31.7°N 92.3°W and was moving north-northeast at about 9 mph. Heavy rains have finally moved out of most of Texas, but are now spreading into Western Louisiana. Heavy rains should spread over the Southeastern United States this weekend in association with Harvey. Harvey is likely to continue on a north-northeastward to northeastward path, likely dissipating over Kentucky by Friday. Advisories on Harvey will now be issued by the Weather Prediction Center (WPC) since the cyclone is inland and has weakened to a tropical depression, as long as it remains a flood threat.

Tropical Storm Irma forms over the Eastern Atlantic, expected to steadily strengthen

Invest 93L over the Eastern Atlantic developed into Tropical Storm Irma Wednesday morning, and has already strengthened into a strong tropical storm. As of 11:00 p.m. EDT Wednesday, Tropical Storm Irma was centered near 16.4°N 32.2°W, and was moving westward at about 12 mph. Maximum sustained winds were 55 knots (65 mph), with an estimated minimum pressure of 999 mb. Irma has become better organized throughout the day, with curved banding features present and a primitive eye feature developing. Intensification is expected, and Irma is likely to become a hurricane tomorrow over the open Atlantic. Irma is then likely to intensify into a uncommon major hurricane in the Atlantic Main Development Region (MDR) by early next weekend. Irma is expected to be in an environment of light wind shear, less than 10 knots, for the next five days, which favors intensification. However, marginal sea surface temperatures and mid-level dry air may limit Irma from becoming stronger than a category 2 or 3 hurricane over the next few days. By next week, Irma may be at or near category 4 strength near the Northern Leeward Islands.

It is uncertain exactly which track Irma will take, and it is too soon to determine if it will pose a long-range threat to the United States. Normally, a tropical cyclone forming this far north and east would recurve out to sea. However, the subtropical ridge is expected to be strong by the weekend, and Irma is expected to take a dive to the southwest, and this complicates the idea of a recurve out to sea. Irma will likely be near or just north of the Leeward Islands in about seven days. There is a strong consensus among nearly all global models and intensity guidance that Irma will be a strong hurricane next week.  The ECMWF model is farther south and predicts that Irma could be near the Bahamas in about 10 days, while the GFS model is farther north and predicts Irma will recurve out to sea, possibly posing a threat to Bermuda. I think a track between the United States and Bermuda is most likely as of this time.

Elsewhere in the tropics 

Tropical Storm Lidia has formed over the Eastern Pacific, and is likely to make landfall in the Southern Tip of Baja California tomorrow evening. Lidia was centered near 20.7°N 109.2°W, and was moving north-northwestward at about 7 mph. Maximum sustained winds were 35 knots (40 mph), with an estimated minimum pressure of 1001 mb. A Hurricane Watch and Tropical Storm Warning is in effect for the Southern Baja area. Lidia is likely to strengthen into a strong tropical storm or perhaps a minimal hurricane before landfall tomorrow. A reconnaissance aircraft is scheduled to investigate Lidia tomorrow.

There is the possibility of another area of low pressure forming over the Southwestern Gulf of Mexico by early next week. The National Hurricane Center (NHC) gives this disturbance a near zero percent chance of development within 48 hours, and a 20 percent chance within five days. If this system develops, it could impact some of the same areas that dealt with flooding rains from Harvey. However, it is too soon to determine if this system will even develop, and if it does, it may remain away from Texas.

I will be back with another post tomorrow.