US Weather Commentary

Location: New York
Author: Michael Schlacter
Date: Wednesday, August 1, 2007
 

Tropical Storm CHANTAL upgraded in Northern Atlantic.
  • Those who wrote-off 2007 Season just days ago, now rudely awoken for active August-October stretch....

True to form and as expected, the National Hurricane Center classified Tropical Depression # 3 during the overnight hours last night and upgraded it to Tropical Storm Chantal this morning. This was well ahead of the August 20th average date we witness the 3rd Named Storm of the Season.

Yesterday we reminded you to keep in mind that NHC has a disproportionate classification tendency (statistical bias) in officially declaring storms either during the 4 PM - 3 AM "post-day" window or over the Weekends, (when official public announcements have minimal market impacts). Also, NHC is quicker to "pull the declaration trigger" when a system is closer to North America and can pose either a direct (landfall/strike) or indirect (such as rip currents, wave swells and beach erosion) to a populated land mass. Additionally, Sub-Tropical Storms are now qualified to be named by NHC (since 2002), so close-to-land hybrid storms are also given the benefit of the doubt with regards to classifications & upgrades, so be aware of these more lenient protocols (and conversely stricter standards in the far Atlantic), during the Season.

Chantal is trekking to the North-Northeast at a brisk 21 mph, should graze Newfoundland and head to the North Atlantic (towards Iceland),  transforming completely to an Extra-Tropical Low.  Extra-Tropical Low Pressure systems (such as Winter Nor'Easters) are no laughing matter and can reach Hurricane-strength (from Baroclinic processes), so maritime interests, the U.K. and Scandinavia should be alert and prepare for the downstream rain & winds impacts from this storm.

The next system on the docket is the Tropical Wave in the Central Atlantic, about 650 miles away from the Caribbean (Windward Islands), which we have been monitoring for almost a week now. In this instance, "Wish-Casting" had some meteorologists Monday underestimating the potential of what is now Tropical Storm Chantal, and overestimating the immediate prospects of the central Atlantic tropical wave (by not properly factoring in the inhibiting effects of the Saharan Air Layer).

Such classic "Cape Verde" storms often earn the psychological spot-light straight off the bat, because their low-latitude, plenty of time to work with, Caribbean-pointed vectors cause people to visually extrapolate to North America or even the Gulf of Mexico. But there are 101 reasons why a Tropical Storm will not do what a computer model says it will do even 3-5 days hence, so specific track & strength extrapolations 7, 9, 11 days into the future become ludicrous if not comical, as these throwing-dart proclamations have very little to lose (people forget the 99% of calls that go awry). 

That being said, if the system can overcome the dry-air impediments, the prospects for T.D. # 4 and/or Tropical Storm DEAN classification is favorable within the next 24 hours.  It is very rare for tropical systems to travel in a straight bee-line remaining below 15° N Latitude, so be prepared for computer models to shift further North and arc its path more as time goes on.

Due to the lower-priority/low-threat status of the North Atlantic system, we elected not to disturb you with T.D. # 3 pre-announcement last night, and waited to inform some by IM early this morning (5 AM EDT).  Generally however, if and when an official NHC declaration of concern (Tropical Depression, Tropical Named Storm, or Hurricane) is about to be announced (NOT speculation), you will hear from us first (via IM or Text), 15 minutes to 3 hours before it is disseminated across public weather or news wires.  If you would like to be informed in a timely manner, and we do not have your IM or Text information, please pass it along so we can update our files.

For your reference, the next 3 names given to Tropical Storms this Season are: CHANTAL, DEAN and ERIN

Tropics In Perspective:

  • The average date we witness our 2nd Named Storm of the Season is August 6th. {We reached this mark on June 1st this year}.
  • The average date we witness our 3rd Named Storm is August 20th {We reached this mark on July 31st this year}.
  • The average date we witness our 1st Hurricane of the Season is August 14th. 
  • Ninety-one percent of all Major Hurricanes in the GOM have taken place between August thru October
  • Every Category 5 Hurricane in the GOM, in history, occurred after August 1st
  • Seasonal Hurricane outlooks that have recently been reduced are due to the outlooks being overly aggressive in the first place, as well as anxiousness about (a typical) July lull.
  • Conversely, others might get excited about every thunderstorm cluster that pops up from Cancun to the Cape Verdes, but there are multitude of factors that need to be achieved in order for Tropical Cyclone formation to occur despite how "scary" it may look on a satellite image.

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