2012 Atlantic Hurricane Season Birdseye Discussion #38A (Special Update)

By: NCHurricane2009 , 11:33 PM GMT on June 28, 2012

...JUNE 28 2012...7:25 PM EDT...
This is a special update from full discussion #38 concerning the remnants of Debby.

The remnants of Debby have turned eastward toward Bermuda while steered by strong surface low located over Nova Scotia mentioned in paragraph P2 of full discussion #38. Even though her satellite appearance is still suggestive of a system entagled along a frontal boundary...she appears to be re-gaining tropical characteristics with more symmetry in her storm clouds. Her satellite apperance and low surface pressures (as analyzed on the NHC TAFB maps) suggest she may have re-gained tropical storm strength since she left Florida...which in part is due to divergence ahead of the east US upper trough (paragraph P2 of full discussion #38). Because she is moving even faster...her shear relative to strong upper southwesterly winds from the east US upper trough has dropped...which explains how her storm clouds have gained symmetrical distribution. Her fast pace continues to defy the speed suggested by my final (and the NHC's final) forecast track back during discussion #37...when Debby was last tropical. The more recent eastward turn began to veer from the NHC's last forecast track and better match mine (which had a southward bias)...but now neither my nor the NHC's last forecast is accurate at this time with the continued eastward movement.

In summary...we can now expect Debby to bring tropical storm-like conditions to Bermuda tomorrow as the center passes over or just north of the island (as estimated in Figure 1 below). I would not be surprised if the National Hurricane Center re-upgrades Debby to a tropical storm later tonight...which would require a sudden tropcial storm warning for Bermuda. The Nova Scotia low's eastward progress is being blocked by strong upper ridging (paragraph P3...discussion #38) and strong surface ridging (paragraph P5...discussion #38). Using the quasi-stationary Nova Scotia low as the steering feature...and using the curvature of clouds about the Nova Scotia low...I estimate the trajectory of Debby will be as shown in Figure 1.

Refer back to discussion #38 for current situation on the rest of the Atlantic tropics.


Figure 1: Current analysis of Debby's situation. Trajectory suggests the center will pass directly or just north of the island of Bermuda.


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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