Erika Forecasts Don't Mean Much

By: Bryan Norcross , 1:23PM,GMT on August 27,2015

Tropical Storm Erika is a little stronger this morning, but is still plenty messy, and still not organized enough to presume that the models can get a good handle on it so we can have confidence in the long-term forecast. Strong unfavorable upper-level winds are keeping the system from pulling itself together. When tropical systems are discombobulated, the forecasts are always suspicious, and prone to change every time there is a new model run. So there is no sense feeling relief or anxiety just because the forecast changes for better or worse when a messy storm is four or five days away. It’s wasted energy.

As I mentioned yesterday, Erika seems to be staying toward the left side of the cone which will take the center toward Puerto Rico and Hispaniola where the mountains will disrupt the circulation and the upper-level winds are expected to be even more unfavorable than now. Our hope is that those mountains combined with the unfavorable upper-level winds will shred the circulation so we can forget about it. But we can’t bet on it.

The problem is, if even a decent remnant remains, the atmospheric pattern over Florida and the Bahamas is forecast to be ideal for a system to quickly strengthen IF it can hang together.

The trend in the forecast last night was to shift more of the possible tracks offshore of the east coast of Florida. But it’s way too early to have confidence in that forecast, and in any case many possible tracks on the left side of the cone still came over the peninsula. Now the European model – one of our most reliable – has switched back to the bringing the storm over Florida. So it's very nice that we have these models that we can follow minute by minute, but individual runs of individual models are not relevant. We're not even sure how this thing is going to look tomorrow, so looking for an exact forecast for any particular location late in the weekend is a fool's errand.

So for now let’s see what happens today and tomorrow. Bottom line, it’s not out of the question that Florida is going to have to deal with this late in the weekend. And this uncertainty means there are fewer days to get organized if the threat quickly materializes.

Even if the storm misses Florida to the east, in the long term is might stall or loop or do something else annoying. So stay informed and don't be surprised.

In any case our friends in the Bahamas need to be on higher alert. There is a good chance that some version of Erika – from a gusty rain to a hurricane – will affect the island chain. And the storm may well be strengthening as it moves from south to north through the country beginning late tomorrow.

The bottom line is, until this comes into focus, everybody from the Bahamas to Florida to the southeast coast – including Georgia and the Carolinas – has to be vigilant at least for the next several days.