cieldumort
(Moderator)
Thu Sep 20 2018 02:40 AM
98L Lounge

Below: GFS Surface (10m wind and MSLP) analysis Sep 20 0z


Florence is no longer, having transitioned into an elongated trough of low pressure, and ultimately merging with a mid-latitude system and becoming part of the reason for frontogenesis while exiting the east coast. This merged system, with scant Florence DNA left in it, is now well offshore of the east coast and has a couple of lows developing within it.

For a few days, several models have had runs pinching off the southern extent/s of this system, with one or two synoptic-scale lows taking off on their own with subtropical or even tropical development. The NHC has outlined in this morning's TWO the region they consider the most promising for development within the next 5 days, and have placed a broad 40% oval around 34N 46W.

From this tonight's TWO
Quote:

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Thu Sep 20 2018
A non-tropical low pressure system is forecast to develop by Friday night over the central subtropical Atlantic Ocean between Bermuda and the Azores. Conditions are expected to be conducive for the low to acquire some subtropical or tropical characteristics, and a subtropical or tropical cyclone could form over the weekend or early next week while the low meanders over the central Atlantic Ocean.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.



Another region not currently mentioned by the NHC, but which is closer to land, has some models showing a bit of run-to-run consistency for development occurring between Bermuda and the South Atlantic states.

If one or both of these modeled Lows gets Invest tagged, which looks very possible, the title of this thread will be changed with whichever one picks up a tag first. If the second is also tagged, it will be placed in its own Lounge.

*The formerly non-tropical gale center located near Bermuda has just been tagged Invest 98L and the title of this thread has been changed accordingly. This system is already producing sustained winds to tropical storm force and watches/warnings may be issued as soon as today. - Ciel



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