Tropical Storm Isaias strengthened into a hurricane early Friday as it pulled away from the Dominican Republic and headed towards the Bahamas. Meanwhile, the threat to the East Coast is starting to increase.

As of early Friday morning, Isaias was centered about 45 miles southeast of Great Inagua Island in the southeastern Bahamas, and was moving toward the northwest at 18 mph. Maximum sustained winds have increased to 80 mph based on recent data from reconnaissance aircraft. A Hurricane Warning is in effect for the northwestern, central, and southeastern Bahamas.Tropical Storm Warnings remain in effect for the entire Dominican Republic, the north coast of Haiti and the Turks and Caicos Islands. A Tropical Storm Watch is in effect for the east coast of Florida from Ocean Reef to Sebastian Inlet.

The short-term forecast for Isaias is rather simple. It will continue to move toward the northwest across the Bahamas while gradually slowing down. Waters remain very warm in this area (29-31C), and wind shear shouldn’t be that strong, which will allow Isaias to strengthen a bit more over the next day or two.

Once Isaias gets into the northwestern Bahamas, things get a bit trickier. A large high pressure area in the western Atlantic, and a trough of low pressure moving into the eastern United States will help to steer Isaias more towards the north-northwest, and then north, and eventually northeast. Exactly when those turns occur is critical to the forecast.

The current forecast calls for Isaias to make the northward turn east of Florida, sparing the Sunshine State from the worst of the storm. It may be close enough to bring some gusty winds and heavy rain to east-coastal Florida over the weekend, which is why the Tropical Storm Watch has been issued. That watch will likely be extended farther north on Friday. After that, it will head towards the Carolina coastline late Sunday into Monday. This is where the uncertainty is magnified.

If the Western Atlantic high is stronger than currently expected, or if the trough moving into the East is sharper than the models are currently showing, then Isaias will continue northward, likely moving across eastern North Carolina. A weaker high or flatter trough, would allow for a more northeastward movement, which could allow Isaias to only graze the Outer Banks or possibly even miss them completely.

Once the storm is beyond the Carolinas, there is more uncertainty with its track. Again, a more northeastward motion would bring the storm out to sea with little additional impact to any land areas. A motion that is more toward the north-northeast or even north would increase the threat to parts of the Northeast, including New England, for late Monday or Tuesday.  As this point, coastal residents from Florida to New England should all keep tabs on the storm’s progress, as it could impact a large stretch of coastline this weekend and early next week.

If Isaias does make its way to New England as a hurricane, it would be extraordinarily early in the season for an impact up here. The earliest that a hurricane has ever made landfall in New York or New England was when Hurricane Belle slammed into Long Island with 90 mph winds on August 9, 1976. Hurricane Arthur passed just offshore of Nantucket on July 4, 2014. While it did not make landfall, it made for a rather wet and cool holiday, especially across Cape Cod and southeastern Massachusetts. Statistically, the most likely time for a hurricane to hit New England is between the middle of August and late September. Of the 18 hurricanes that made landfall in New England or Long Island since 1851, 16 of them have done so between August 19 and September 27. Since 1951, 36 storms have made landfall in New York or New England as tropical storms or hurricanes, but only 5 have done so before August 5.

• An Unnamed Tropical Storm crossed Long Island on May 30, 2008 with winds of 45 mph.
• An Unnamed Tropical Storm made landfall new Newport, RI on July 21, 1916 with winds of 70 mph.
• Tropical Storm Cindy made landfall near Falmouth, MA on July 11, 1959 with winds of 60 mph.
• Tropical Storm Agnes made landfall near New York City on June 22, 1972 with winds of 65 mph.
• Tropical Storm Beryl crossed Nantucket with winds of 50 mph on July 21, 2006.

If it seems like we’ve been talking about this storm for a while, it’s because we have. Isaias was well-advertised by the models for almost a week before it finally developed over the eastern Caribbean on Wednesday. We even mentioned it in our Weekly Outlook early Monday morning. It has produced wind gusts of up to 60 mph and heavy rain that produce flooding across parts of the Virgin Islands, Puerto Rico, and the Dominican Republic. Wind gusts as high as 54 mph were also reported in the Turks and Caicos Islands Thursday evening.

We’ve been mentioning for several days now that a wave in the Atlantic needed to be watched for development. It isn’t a tropical cyclone yet, but it appears to be a matter of when, not if, it will become one.

While the system has a broad circulation and plenty of thunderstorm activity, it has not become a tropical cyclone as of yet. Until that circulation tightens up into a well-defined low-level center, it is just a tropical disturbance. The National Hurricane Center has dubbed it “Potential Tropical Cyclone Nine” as of midday Tuesday. This designation allows the issuance of Tropical Storm Watches and Warnings for many of the islands in the northeastern Caribbean, including Puerto Rico and the Virgin Islands. The center of the system is estimated to be about 500 miles east of the Lesser Antilles. It is moving toward the west at 23 mph, and has maximum sustained winds of 40 mph. The expectation is that the circulation will tighten up and the system will become a tropical storm in the next 24 hours. If it does, it will be given the name Isaias (pronounced ees-ah-EE-ahs). This has already led to many in the media and on the internet saying that it is the earliest “I” storm on record. This is true, but it ignores the fact that at least 2 of the storms we’ve had so far this season should not have been named.

Air Force reconnaissance aircraft are out investigating the system this afternoon, trying to determine its strength and whether it has developed a low-level center yet. Once that center does develop, we’ll have a better idea of where the system may go. Right now, the forecast is for the system to cross the Lesser Antilles early Wednesday, then move across the Virgin Islands and Puerto Rico Wednesday night and early Thursday. However, if recon finds that the center has developed in a spot that is not near where the Hurricane Center currently thinks it is, that will obviously have implications on the track of the system. Changes to the track will also have implications for how strong to system gets. As we’ve been saying for a few days now, until the system actually develops, all model forecasts for the system are suspect.

Obviously, minor details could have major implications om the system’s future, but right now, it looks like it will track near or just north of the Greater Antilles. How close to passes to the islands will determine it’s strength. The closer it is, the more likely it is that the mountains of Hispaniola disrupt the circulation and keep it weak. The farther away, the more likely it stays mostly over water and strengthens while possibly impact the Bahamas along the the Turks and Caicos Islands. We’re not even going to speculate beyond that, because even forecasting this far out is more speculation than we’d like. We’re highly aware that many models, especially the ensembles show a threat to the East Coast, literally anywhere from Florida to Nova Scotia. We’re not ruling that out yet, but again, it is pure speculation at this point. We’ll say it again – once the system actually develops, we’ll start to have a better idea of where it’s going and how strong it may be. For now, it’s just something to keep an eye on.

Between the Atlantic and the Central Pacific Ocean we have three named storms, and all of them will threaten land areas this weekend.

We’ll start again with Tropical Storm Hanna, since it is the most immediate threat to land. As of 8pm EDT, the system was centered about 190 miles east-of Corpus Christi, Texas, moving toward the west at 10 mph. Maximum sustained winds were near 50 mph and additional strengthening is likely. Hanna could become a hurricane before making landfall in south Texas on Saturday. A Hurricane Warning is in effect for the Texas coast from Baffin Bay to Mesquite Bay, and a Storm Surge Warning is in effect from Baffin Bay to Sargent. A Tropical Storm Warning is also in effect from Baffin Bay southward to the mouth of the Rio Grande, and from Mesquite Bay northward to San Luis Pass.

A storm surge of 2-4 feet is likely near and to the north of landfall. and strong winds are also likely near the coast and a short distance inland near landfall, but heavy rain and inland freshwater flooding remains the biggest threat with this system. Slow-moving tropical systems have produced significant rainfall in Texas many times before, and while we’re not expecting 50+ inches like Hurricane Harvey produced a few years ago, widespread totals of 6-12 inches with isolated amounts of up to 20 inches are possible through early next week. To the north, rainfall of 2-6 inches will likely cause flooding from Austin and San Antonio over to Houston.

While Hanna is the immediate threat to the US, out in the Atlantic, Tropical Storm Gonzalo is a threat to the southern Windward Islands. As of 8pm EDT, Gonzalo was centered about 340 miles east of the southern Windward Islands, moving toward the west at 18 mph. Maximum sustained winds have decreased to near 45 mph. Drier air has taken a toll on the system, and will continue to do so. A Tropical Storm Warning remains in effect for St. Vincent and the Grenadines, Tobago, and Grenada.

Gonzalo’s future remains very uncertain. The official forecast calls for Gonzalo to restrengthen a little over the next 24 hours, then weaken and dissipate after moving into the eastern Caribbean. However, at this point, it is just as like that it weakens and opens up into a wave before it crosses the islands on Saturday. No matter what it does, it will bring some squally weather to parts of the southern Windward Islands on Saturday. We’ll also need to keep an eye on what the remnants of the system do as they move across the Caribbean. Conditions in the western Caribbean could be a bit more favorable early next week and the water is plenty warm, so regeneration is not out of the question.

In the Central Pacific Ocean, Hurricane Douglas is starting to slowly weaken after peaking as a Category 4 Hurricane on Thursday. As of 8pm EDT, Douglas was centered about 725 miles east-southeast of Hilo, Hawaii, moving toward the west-northwest at 18 mph. Maximum sustained winds have decreased to 115 mph, making Douglas a Category 3 storm on the Saffir-Simpson scale. Some additional weakening is expected on Saturday as Douglas moves over cooler waters. A Hurricane Watch has been posted for Hawaii County and Maui County, including Maui, Lanai, Molokai, and Kahoolawe.

The forecast track for Douglas has shifted northward a bit over the past 24 hours, but still indicates the potential for Douglas to impact Hawaii as a weakening hurricane on Sunday, though some models keep the center north of the island chain completely. Rough surf, gusty winds, and heavy rainfall are likely across the islands starting late Saturday and continuing into Monday. Rainfall totals of 6-12 inches and locally up to 20 inches may cause flooding in some areas.

Finally, we’re keeping our eyes on a tropical wave in the eastern Atlantic Ocean. The wave isn’t that organized right now, but as it crosses the Atlantic, conditions could become more favorable for development. In fact, many models do show this developing into a tropical cyclone towards mid-week, and possibly becoming a threat to the eastern Caribbean by late next week. Model forecasts 5-7 days out aren’t terribly reliable, but there are some that show the system becoming a threat in about 10-12 days to anywhere from Central America to the Gulf to the East Coast, to Bermuda, to a system that passes harmlessly out to sea. In other words, it’s WAY to early to speculate about a system that hasn’t even formed yet. Yes, it’s something to watch, but that’s about it right now.

Scheduling Note: Our Weekend Outlook will be published early Friday this week instead of Thursday afternoon as it usually is.

The tropics had been relatively quiet in the past couple of weeks, but we suddenly have 3 storms that are all threats to land.

We’ll start with Tropical Depression 8, since it is the most immediate threat to land. As of 11am EDT, the system was centered about 380 miles east-southeast of Port O’Connor, Texas, moving toward the west-northwest at 9 mph. Maximum sustained winds were near 35 mph. The system should continue on a general westward track for the next day or two, with some strengthening possible. As a result, a Tropical Storm Watch is in effect for the Texas coast from Port Mansfield to High Island.

While gusty winds and some rough surf are likely along the Texas coast, the biggest threat from this system will be heavy rainfall. Slow-moving tropical systems have produced significant rainfall in Texas many times before, and while we’re not expecting 50+ inches like Hurricane Harvey produced a few years ago, widespread totals of 3-6 inches with isolated amounts of up to 10 inches are possible this weekend. That would produce flooding in many areas.

While TD 8 is the immediate threat to the US, out in the Atlantic, Tropical Storm Gonzalo presents a threat to parts of the Windward Islands. As of 11am EDT, Gonzalo was centered about 885 miles east of the southern Windward Islands, moving toward the west at 14 mph. Maximum sustained winds are near 65 mph. A Hurricane Watch is in effect for Barbados as well as St. Vincent and the Grenadines.

Gonzalo’s future is very uncertain. The official forecast calls for Gonzalo to become a hurricane later today, then start to weaken after moving across the Windward Islands this weekend and into the eastern Caribbean. However, Gonzalo looks less organized on satellite photos today, and is fighting off some dry air aloft. There is a decent chance that the system could weaken or even open up into a wave before reaching the Windward Islands. How it develops over the next 12-24 hours will give us a much better idea of what the future holds for it.

In the Eastern Pacific Ocean, Hurricane Douglas continues to strengthen this morning, and could become a threat to Hawaii this weekend.

As of 11am EDT, Douglas was centered about 1335 miles east-southeast of Hilo, Hawaii, moving toward the west-northwest at 20 mph. Maximum sustained winds have increased to 120 mph, making Douglas a Category 3 storm on the Saffir-Simpson scale. Some additional strengthening is possible today before a weakening trend begins on Friday as Douglas moves over cooler waters.

Douglas is expected to only gradually weaken while heading towards the west-northwest over the next several days. On this track, Douglas is expected to pass close to or over parts of the Hawaiian Islands this weekend. Obviously which islands would be impacted and what the threats would be will depend on the exact track Douglas takes, as well as how quickly it weakens. At this point, gusty winds, heavy rainfall, and rough surf appear mostly likely for the Big Island, but the entire island chain could be impacted.

While Hawaii has been impacted by many weakening storms passing by the islands, a direct hit is actually fairly rare. Since 1871, only 3 hurricanes and 4 tropical storms have actually made landfall on the islands. The last system to make landfall in Hawaii was Tropical Storm Olivia in 2018. The last hurricane to make landfall in Hawaii was Hurricane Iniki in 1992.

Beyond these systems, there’s nothing on the immediate horizon. Some of the longer-range ensemble models are showing the potential for a wave to move off the the African coast and develop while crossing the Atlantic next week. This is still several days away, and while the likelihood of it happening is fairly low, we are getting into the time of year when some of these waves do start rolling off of Africa and maintain themselves while crossing the Atlantic. Just like in the winter when you’ll see Day 16 model images of a mega-blizzard for the Northeast, we’re already seeing people posting model images for a potential East Coast hurricane 2 weeks from now. Don’t buy into the hype. Until something actually develops, it doesn’t exist, let alone present a threat.