UPDATE: NHC now issuing advisories on Potential Cyclone Nine

Posted at 7:21 AM, Jul 28, 2020

Update 10:30 am: Invest 92, has now been designated as potential tropical cyclone nine, a specific designation that signifies the official formation of a tropical storm can not be confirmed but that formation is imminent.

This allows the National Hurricane Center to start issuing advisories and tracks for the storm as it approaches the Caribbean Islands later this work week, it also will help model runs in the future now that there is a center of circulation the models can use to originate the storm.

The models, now having a specific focus, means we can start building a little confidence in the forecast.

The following was written earlier in the day and the main talking points and discussion on forecast details will remain the same, this intensification was taken into account during the forecast period.


Monday wasn't a great day for Invest-92, a tropical wave which is currently sitting in the western Atlantic, with dry air and shear keeping it from coming together and becoming the ninth storm of the season.

The wave is looking a little more open early Tuesday which will allow some of that dry air to get a little more embedded into the system, preventing it from really taking off, but it is showing signs of battling back a little bit of that dry air.

While the environment isn't overly favorable for development, based off the sea surface temperatures which are running above normal it's still hard to rule out further development completely.

There's a little model support for further development, with both the GFS and EURO producing a weak low as it approaches the Caribbean, and eventually pulls that low toward the peninsula of Florida.

It's worth noting that these models will really struggle with this system, genesis of these storms is still really tough to forecast, and until that happens models may be up and down which doesn't build much confidence.

Still though I think it's worth a look into the tea leaves of what these models are saying because there's still some value to be found there, as long as the proper grains of salt are taken when so doing.

We'll use the EURO, which looks fairly similar to the GFS, as the EURO has remained consistent for the last few days which helps build a little confidence (which with this forecast confidence can be hard to come by).

The last several days the EURO has hinted that the moisture from this wave will try and get into the Gulf of Mexico, via the Florida Straights, before eventually taking a hard turn to the north east.

There's a few different features that should be highlighted both of which would pose well for those of us in Louisiana which would help keep this burst of moisture from sitting and festering in the Gulf of Mexico.

The first of which is the ridge sitting in the Atlantic, one of the dominant features in steering these storms, as the wave approaches south Florida that ridge starts to retreat to the east which opens the door for the wave to move pole-ward.

This is then followed up by an areas of low pressure moving across the Midwest over the weekend which will move north of the wave and out into the Atlantic by early next week.

Coupled with the retreat of the high, this low is important because it actually helps pull the wave onto the western fringe of this ridge and keeps the wave from becoming separated from the steering currents and left to drift in the Gulf of Mexico.

As mentioned earlier when you start talking almost a week out with a tropical wave you end up dealing with a lot of "if this and if that" which will effect confidence in the forecast, but these will be the trends and features to monitor over the coming days.

Elsewhere in the tropics we're getting a little bit of help from another push of dust which will slow down the wave train for a week or so, although there's no telling how long that break will last.

There's still plenty of moisture coming off the African coast and sea surface temperatures through the Atlantic Basin continue to run above normal, this is alarmingly true in the Gulf of Mexico which is running real warm.