It’s hot and muggy with a low chance for PM storms – in other words, it’s summer in the Valley…so let’s talk Tropics.
The tropical Atlantic typically gets more active this time of year. And, with two named storms so far this week plus a disturbance we’re watching closely…that certainly seems to be the case this year. Fiona has basically fizzled and Gaston should remain out to sea. It’s the disturbance moving into the Caribbean that could threaten the U.S.
If you’re an avid consumer of weather info on social media, you’ve probably seen numerous projections of where this storm is headed. Can you trust any of them? In short; no, not really…at least the projections for early/mid next week. There’s still too much uncertainty to say (with any degree of confidence) where this system will be 5-7 days from now. This tropical wave is still poorly organized with no clear center of circulation.
As a result, computer models will have bigger errors in predicting that center track…and those errors grow with time. As is typical, even a specific computer model can have wild fluctuations in position and strength from one run to the next. In fact, the most recent run the European weather model (which typically has a better track record than its American counterpart) shifted a Gulf Coast landfall about 550 miles east of the landfall location on its previous run.
Important note: the above graphic is to illustrate the run-to-run fluctuations on the same model…this is not our forecast. While this is a possibility, there are a number of other scenarios that are just as likely. It's too early to make a call with any certainty regarding the forecast early next week.
This system will continue to track northwest, and should head towards the Bahamas/south Florida this weekend. There is high confidence that’s where the system is headed in the next 2-4 days. Confidence drops after that…unfortunately, it’s that aspect of the forecast (days 5-8) which many of you want to know about since that’s when the system could impact the Valley. Note the ‘could’ in that last sentence…I simply can’t give a definitive yes or no at this time.
Rather than dig into the what if scenarios, let’s focus on what we’re more certain about. Regardless of whether or not this disturbance becomes TS/Hurricane Hermine, it will cause problems throughout the eastern Caribbean. Flooding and landslides would be most pressing concerns, especially for countries like Haiti and the Dominican Republic due to extremely varied terrain. Those heavy rains will track towards Florida and the Bahamas over the weekend.
Beyond that, frankly, we don’t know exactly what will happen next. What remains to be seen; how the storm will interact with the higher terrain of Hispaniola, whether or not the center of circulation can get better defined and stay over water, and the exact position/strength of a steering ridge of high pressure will set up. All will play a role in determining whether or not we feel any impacts from this system.
You’ll want to check back later for an updated forecast.
-Meteorologist David Ernst