10:15 AM (Tuesday) | *Tropical Storm Bret can intensify into hurricane status in the near-term, but some weakening is likely thereafter*

Tropical Storm Bret is likely to encounter some dry air later in the week as it treks towards the eastern Caribbean Sea. A large dry air mass has pushed westward in recent days from the Sahara Desert region of northern Africa into the Atlantic Basin. Map courtesy University of Wisconsin/CIMSS

Overview

The Atlantic Basin tropical scene has come to life in recent days with two systems located in the tropical Atlantic. The front running system has reached named tropical storm status (“Bret”) and it could very well intensify into a hurricane during the next couple of days as it heads towards the eastern Caribbean Sea.  Later in the week, however, a few factors are likely to come together to cause a weakening of this initial tropical system. A second system following closely behind Bret could reach named tropical storm status as well in coming days (would become “Cindy”) as it heads on a general westward track.

Two systems on the map this morning with the “front runner” now a named tropical storm (“Bret”). The second system closely behind has a better than even chance of attaining named tropical storm status as well in coming days. Map courtesy NOAA/NHC

Details

Tropical Storm Bret has sustained winds of 40 mph and is moving on a westerly track at 17 mph which would take it to the eastern Caribbean Sea by the late week or early weekend  High pressure is positioned to its north at this time producing an overall environment in the region featuring low wind shear and the tropical system is moving over abnormally water waters - both of which are favorable for some intensification. As a result of these favorable atmospheric and oceanic factors, there is a decent chance that Tropical Storm Bret intensifies into a hurricane during the next couple of days.

Strong ridging aloft over southeastern part of Canada is often favorable for tropical activity to “undercut” and head westward towards the US. However, this ridge aloft will weaken by the time it gets to the northwestern Atlantic early this weekend. Map courtesy NOAA, tropicaltidbits.com

Later in the week, however, there are a few factors that are likely to combine to cause a weakening process for Bret.  To begin, the low wind shear that is currently in place in nearby proximity to the tropical system will tend to dissipate later in the week as an upper-level trough forms over the eastern Caribbean Sea. The upper-level trough will tend to increase vertical wind shear and this should be a contributing factor to Bret’s likely weakening phase after it potentially intensifies into a hurricane in the near-term.

A strong upper-level ridge located over the Hudson Bay region of Canada at mid-week will tend to weaken as it pushes eastward to the northwestern Atlantic by the weekend. A weak ridge in this location is generally not all that favorable for intensification of a western Atlantic tropical system. Map courtesy NOAA, tropicaltidbits.com

In addition to the expected vertical wind shear, dry air over the eastern Caribbean associated with a Saharan Desert air mass will likely become entrained into the tropical system.  This dry air mass pushed westward in the seasonal trade winds from the northern part of Africa into the Atlantic Basin. Finally, the upper-level pattern in the northwestern Atlantic will not be all that favorable for intensification of the tropical system.  While strong ridging aloft will be situated over the Hudson Bay region of Canada at mid-week – generally a favorable factor for tropical activity in the Atlantic - it tends to weaken by late in the week as it reaches the northwestern part of the Atlantic.

Finally, a word about system number two in the eastern Atlantic Ocean.  This second system that is situated right on the heels of Bret does indeed have a better than even chance of attaining tropical storm status in coming days (would become “Cindy”) as it churns in a general westerly direction…something else to closely monitor.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

Follow us on Facebook, Twitter, YouTube

Video discussion: