US Weather Commentary

Location: New York
Author: Weather 2000, Inc.
Date: Tuesday, September 18, 2007
 

NHC issuing final advisories on dissipating INGRID; Tropics awaiting next conducive conditions....

Ingrid was quite resilient, but the inhospitable environment of damaging wind shear finally got the best of her.  In many ways we dodged a bullet as (1.) Ingrid was drifting much closer to the Leeward Islands than models had accounted for last week and (2.) The same Ridging responsible for the balmy September weather across the East-Half of the Nation later this week, would have helped re-curve Ingrid back towards the East Coast of North America.  While the odds are very low, it's always a good idea to watch the remnants of Ingrid out of the corner of our eye for possible regeneration or transferring her energy to another disturbance, down the road.

The 2007 Hurricane Season has been markedly influenced by the cyclical & periodic timing of favorable MJO pulses + minimal shear alternating with unfavorable MJO & high shear conditions: 

Atlantic Storm formed in                Storm formed near-U.S. and thus

favorable basin environment:      immune to waning basin environment:

DEAN [classified 08/13]                     ERIN [classified 08/15]

FELIX [classified 08/31]                     GABRIELLE [classified 09/08]

                                                     HUMBERTO [classified 09/12]

Hence, INGRID [classified 09/12] was a testament to the consequences of a tropical entity trying to evolve in an inhospitable environment in the far/open Atlantic.  FELIX formed 18 days after DEAN, so on schedule, the next favorable MJO/Shear environment will evolve this week roughly 18 Days after FELIX formed.

There have been 2 main morals of the 2007 Atlantic Hurricane Season, which will hopefully provide over-arching wisdom for the balance of the year:

(1.) An evolving La Niņa, warm ocean temperatures, and modest S.A.L. is going to spin up numerous Tropical Storms (we're already at nine =the average for an entire year), even if folks are chomping at the bit and were closing the book on the Season back on July 30th.

(2.) If oceanographic and atmospheric conditions are too hostile, storms will not develop no matter what computer models depict; if oceanographic and atmospheric conditions are very favorable, storms will form no matter what computer models depict.

Tropics  Pointers:

  • Only about five percent of "entities" that computer models predict to become Tropical Storms actually do so.  Only about 10 percent of Tropical Waves off of Africa become Tropical Storms.  Only about 30 percent of Tropical Disturbances/Waves that NHC gives an "INVEST" designation, actually become Tropical Storms.
  • Keep in mind that the NHC has a disproportionate tendency to classify tropical storms (especially those near North America) on either Weekday Evenings (after 4 PM ET), or on Weekends.
  • For your reference, the next 2 classified Tropical Storms will have the names JERRY and KAREN.

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