The Tropics Are Heating Up With Potential Redevelopment of Helene In Gulf, All Eyes On 94L & 96L


Map courtesy of The Weather Channel


All of a sudden the tropical Atlantic has awakened and there is a lot on the table over the coming 1-2 weeks. While we have two circulations well paying close attention to, we see Gordan drifting and die out in the chilly waters en-reoute towards Portugal following a landfall on Santa Maria Island in th Azores early this morning. At landfall, Gordan packed 75 mph sustained winds with 80 mph winds reported on the southern island. There was minimal damage done to trees and property with some powerloss.

Gordon continues to weaken with models this disipated over the chilly waters off Portugal on Wednesday.

Interestingly, in the last 120 years, the Azores has been struck by hurricanes only 8 times according to the BBC. So, yes rare for but not quite unheard of to see hurricane strike these islands. The last strike was back in 2006 by, yes, you guessed it.. Gordon.

Gordon is seen here decaying fast in the chilly waters between the Azores and Portugal as the sun begins to set (Satellite image courtesy of NOAA)


After Tropical Storm Helene struck the east coast of Mexico, many thought that was the end of this system but thanks to the curculation persisting along the coast and the work of a southbound cold front off the US Gulf Coast, suddenly our eyes return to this circulation.

The circuluation is now back out over the western Gulf where waters are in the mid-80s. With lack of shear, these warm waters and the ventilation presented by the stalled front over the northern Gulf has raised concern over regenerate and this could cause concern to the US or Mexican Gulf Coast.

The still small and weak circulation means that it may meander around the northern Gulf for the next several days and with SST’s near 90F over the north-central Gulf, that is also a concern.

It’s these in-close weak, small circulations which form or refire from existing systems on the tail of fronts over bathtub warm waters which can bring Humberto-like scenarios with rapid development into strong storms or even hurricanes within a matter of 18-24 hours catching many off guard.

‘Rainbow’ satellite image courtesy of NOAA


A seemingly uninteresting circulation with little convection and chocked by dry air would seem to be no concern to the US but this is probably the system most worth watching if you live in the US.

INVEST 94L shows a good low level circulation and although deep convection is somewhat scarce, the system is fighting off a lot of dry air plus SST’s aren’t particularly warm beneath it’s current central Atlantic position. As the system remains weak and feeling only the low level easterly African jet, the system will then continue westwards towards warmer waters which support higher maximum potential intensity nearer the Windwards. Ultimately this system looks to be heading Caribbean-bound and the weaker it remains, the more of a concern this is for the US. Why? because the weaker these systems remain, the less they want to turn north but if this system was to blow up early and catch the upper level steering winds early, perhaps before the Windward Islands, then this would more likely recurve. The problem is the dry air will keep intensification at bay for the next 5 days or so.

Have a look at the below SST’s. Notice they warm considerably near to the Windward Islands.

Courtesy of WeatherBELL Models

The current track looks likely to take soon to be Isaac into the northern Leewards, eventually tracking across the northern Caribbean Sea as an intensifying storm or weak hurricane.

If you notice in the below charts 1) the amount of dry air north of the system which is keeping this system weak and embedded within the low level flow. In map 2) notice the trough to the NW of the circulation. Had this system been stronger then this trough would likely have picked up 94L and turned it north and eventually northeast into the cold North Atlantic waters.

The next 10 days will be very interesting to see whether this system goes.

Chart shows Saharan dry air (Courtesy of CIMSS)


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