Orange Blossoms: The Hurricane Watch for August 5th
Two areas of interest in the Atlantic have 50/50 shots at development in the next week as Dexter moves out to sea.
Florida tropical threat synopsis: The Southeast coast is likely to see locally heavy rain this week from a tropical disturbance that may organize as it approaches the eastern Carolinas. Any other major tropical threats to the U.S. are over a week away.
Almanac: It’s Tuesday, August 5th… day 66 of the 2025 hurricane season, 117 days to go. By total storm energy, the season is 8.3%, 19.6%, and 13.0% complete for the Atlantic, continental U.S., and Florida, respectively. One year ago, Hurricane Debby made landfall in Taylor County, FL near (where-else-but) Steinhatchee. While Debby is a bit of the forgotten middle child in Taylor County’s Trio of Misery, sandwiched between Major Hurricanes Idalia and Helene, it packed a punch in its own right. This is particularly true in terms of surge (up to 6’ in Cedar Key), and flooding rainfall of 10-20” from Sarasota through the eastern Big Bend into coastal South Carolina.
Active Storms: Minimal Tropical Storm Dexter is puttering northeast across the open Atlantic to the north of Bermuda this morning, with maximum sustained winds of 40 mph. Dexter has weakened a little in the last day due to 25 to 30 knots of shear from the west, which isn’t going away. Look for this forgettable storm to continue east-northeast for the next couple days as it loses tropical characteristics, with no impacts.
Other Disturbances in NHC outlook, with 2-/7-day NHC development odds:
As shown on integrated moisture imagery above, the atmosphere over the Southeast U.S. and western Atlantic remains soupy, with total precipitable water of 1.5-2.5” in the air. Convection is likely to become more concentrated in this moist airmass between the Bahamas and the Carolinas over the next couple of days, and the NHC has raised development chances here to 10% through mid-day Thursday and 40% through the weekend. This feature will move slowly north, and is expected to be over or near the eastern Carolinas by early Sunday. While this may get organized enough to snatch a name by the weekend, the most significant impact will be continued elevated rainfall extending from Florida across the coastal Southeast over the next 5 to 6 days, where 2-5” accumulations are likely. Once a more coherent disturbance forms in the next day or two, we’ll have a better idea where the rain (and other) impacts may be most focused.
NWS/WPC forecast 7-day rainfall totals through next Tuesday morning. The tropical wave in the far eastern Atlantic still looks anemic today, but convection has increased a bit since yesterday and the NHC is still giving this wave a fairly bullish 50% chance of development over the next week. As shown on the precipitable water imagery above, there’s decent mid-level moisture in the eastern Atlantic along and south of a monsoon trough, and shear will be below average on the wave’s west-northwest to northwest path over the next 3 to 5 days. August tropical waves have underperformed modeling in the last few years and sea surface temperatures are still marginal north of 15N, so any development is likely to be slow, and probably not until at least the weekend (or later).
06z GFS and Euro Ensemble member low pressure center forecast for early Sunday morning, with sea surface temperature anomalies. (Weathernerds.org) With the Euro ensembles generally showing faster development than the GFS, there continues to be a split in how models are handling this wave in the medium term; by late in the weekend, the Euro generally has a more organized system cruising northwest into the open Atlantic, while the GFS takes a weaker wave more westward. I’m skeptical of the pace at which the Euro organizes this wave, and more inclined towards a weaker/westward track. Farther down the road, that might set up a situation to monitor, should a coherent tropical system make it underneath the western Atlantic ridging still prominent next week in guidance. Any threat is still a long ways off, but a strong “Bermuda high” means we’ll need to carefully watch any tropical systems that make it to the Antilles— particularly as the waters near and east of the Bahamas are much warmer than normal.
Elsewhere: For what it’s worth, the Euro Ensembles are also pretty bullish with the next wave set to emerge from West Africa later this week— another potential Plinko chip to be dropped into a steering wind regime worth keeping an eye on as we go deeper into August and up the slope of rising Atlantic hurricane climatology. The final thing to mention today is the outside chance of yet another spin-up of low pressure along the stalled front over the eastern half of the Gulf over the weekend, which a few ensemble members are hinting at this morning. We’ll see if this gets better defined in the next couple of days, but look for wetter than normal weather to continue along the Gulf Coast for the next 5-7 days regardless.
Next report: Supporter bulletin out early afternoon tomorrow.
Dr., are the brass at TPS still keeping up w/ your missives?
Plinko chip 🤣