Friday, August 17, 2012

Tropical Musings Into Latter August

The tropics continue to stir as we work into the prime six weeks of hurricane season in the Atlantic -- the period from August 15 to October 1 where the brunt of activity takes place in the Atlantic basin.  There are three features out there -- one of which won't matter to anyone but perhaps Europe, that are flaring up at this point.

Tropical Storm Gordon is pushing east-northeast in the Central Atlantic, heading towards the Azores Islands and then eventually towards Europe in about a week's time if it holds together as its own entity.  By the time it passes the Azores, it may lose its tropical identity and merely be a strong non-tropical low and then potentially bring some rain to Europe late next week.  It won't be a threat to the US.

Closer to the US, Tropical Depression 7's remnants are flaring in the Bay of Campeche.  They will make landfall tonight or tomorrow along the Mexican coastline, perhaps regenerating into a tropical depression or sneaking up to a weak tropical storm status before landfall.  Modeling suggests that TD 7's low pressure center may stall out near the Mexican coast but over the Gulf...if that happens it could intensify a bit more since the Gulf is quite warm and shear is low.  However, odds lean for now towards a landfall over the weekend with the system itself.

What may become a "bigger" story in the next two weeks is this low pressure wave exiting off of Africa.    This system could become the next named storm (if TD 7 does not do so first), Helene, in the name pipeline.

This wave has the potential to develop into a strong tropical system over the next week or two as it tracks west across a favorable Atlantic Ocean.  Wind shear is relatively low, there's a relative lack of dry air in the atmosphere in its immediate path (although there's a good chunk of it currently near the Caribbean Islands), and ocean temperatures are nearing their seasonal warm point.  The result could be a pretty significant tropical system in a week's time.  The Euro (below) shows the system to the northeast of Puerto Rico at the end of next weekend...taking a track that is generally west, bending it northwest for a time before turning back to the west-northwest as this system escapes a trough that passes by to its north. The GFS (not shown) brings the storm to about 50 W longitude before it begins to turn northwest, turning north at 60 W and completely missing anyone in North America. In the GFS scenario, the projected mid atmosphere trough catches this storm and brings it north.

It's too early to say that this storm will/will not impact the US, curve out in the open Atlantic, or rip through the Caribbean, but modeling does suggest a formidable tropical system developing from this low in a week or so. If it's strong out of the gate, that trough in the Central Atlantic will probably pull it north sooner and a miss of the US and Caribbean would be the likely result. A weaker system could escape the trough and perhaps get a bit close for comfort. We'll keep an eye on it.