Saturday, July 27, 2013

Dorian's Tough Road Ahead

Tropical Storm Dorian has been battling dry air and shear for the last day now, having weakened a fair amount as it progresses west through the Atlantic. The low pressure center and the thunderstorms associated with the storm have begun to detach apart as upper level winds shear Dorian's thunderstorms away from the low pressure center, which results in a weakened storm.

Things won't get any easier for Dorian over the next two to three days. Dorian is pushing west to the south of a large upper level low pressure center in the Central Atlantic, one that's scheduled to drop south.  Stronger upper level winds reside in Dorian's path (outlined in the belt of arrows coming towards Dorian from the west on the graphic below).  Given the upper level environment out ahead of Dorian, I don't think this is going to end too well for the tropical cyclone in the next day or more.  There are signs this morning with some of the satellite scans that Dorian's circulation may not be fully closed (that's a requirement to maintain the name as well as tropical cyclone're not a cyclone if the low is not a closed circulation!) so some of this may be moot...but in any case, with strong upper level winds ahead, Dorian ain't going to organize much over the coming days and has a relatively strong chance of fizzling at this point.

It may enhance daily rains over Florida around the middle of next week but I don't foresee much chance of this bouncing back as a tropical system as that wind shear ahead of it will prevent storm strengthening.

Dorian's not the only tropical system out there.  Flossie is in the Central Pacific and on a west-northwest track towards the Big Island of Hawaii. Flossie is near hurricane intensity but it may be very close to peaking in intensity as dry air aloft and some upper level wind shear reside in Flossie's path. That said, it looks like it will remain on track to bring some rainfall to the Hawaiian Islands late Monday into Tuesday.