STORM2K

Every year or so I use the search engines on the net to try and find the answer to this question. Never found a thing. But I know it exists, evidenced by many news articles referring to "Tropical Wave Number x" or "Tropical Disturbance x".
See article yesterday at http://www.yucatannoticias.com/en/?p=96
"The federal official said that the tropical wave number 7, located off the coast of Quintana Roo, would cause 5 to 20 mm rainfall on Monday and Tuesday, while on Thursday it is expected to feel the effects of the tropical wave number 8 on this part of the country." Wow, wonder which of the over 20 waves we've had so far they didn't count, to be only up to number 7?

And the most confusing yet, about 92L (I think from Antigua Met Service), which got posted all over the internet via news services, forums, online radio, etc., stated:
"Tropical Disturbance 10 was located about 625 miles east of the Lesser Antilles. Movement continues west-northwest to northwestward at about 15 mph. Showers and thunderstorms within this system are poorly organized and the strong westerly winds at upper levels are expected to remain unfavorable for tropical cyclone formation. There is a ten percent chance of this system becoming a tropical cyclone during the next 48 hours."
This information on Disturbance 10 was updated a few days in a row, and mass-distributed by email. We expect the same will happen for each and every unorganized something that is being watched.

So what was Disturbance 1 through 9? And why, when the World Meteorological Organization has designated the National Hurricane Center as the forecast agency for the Atlantic Basin, and there is an accepted protocol of terminology, etc., does another set of numbers show up which have no documentation, and confuse the public? They sure don't mind using word-for-word the Tropical Weather Outlook from NHC. So why add the "Tropical Disturbance 10"? Does anyone know where I can see these numbered "disturbances" or even "twaves" on the net? Or do the numbers mean anything at all, other than something to the person/organization using them?

I've searched the web using "tropical wave number(s)(ing)" - nothing found. Also searched same for "tropical disturbance" and learned that is a valid classification in the SW Indian Ocean, and read hundreds of pages of the same stuff about cyclones, depressions, storms, tropical waves, coriolis effect, etc. the whole bulk of usual stuff and never found ANYTHING about numbering twaves or "tropical disturbances" in the Atlantic (which, by some definitions, is the same thing as twaves). Anybody shed some light on this?

It's highly possible that each individual country/weather service only numbers waves or disturbances (general tropical cloudiness associated with the ITCZ) that affect its warning area, hence a difference in numbering between their own designations and the TPC/NHC - meaning a disturbance within the ITCZ the NHC didn't expect to develop could've passed over Anguilla and be numbered. Nothing expressly wrong with it, especially if the main target of this information is the public within that warning area.

The numbers could be just a way to keep track of the waves (just like naming TCs) and then used for archive purposes for each season (i.e. "Twave 10 killed x people due to mudslides in 2010")

I know where one of those reports came from, bvigal - a private consulting firm in Houston, TX! British Virgin Islands Office of Disaster Preparedness is a client of theirs, I believe. They number each disturbance that they identify out in the tropics through the season from 1 through whatever. Most never have much chance of development, but some are more significant than others. For these waves/disturbances, they issue special discussions, like the discussions from Disturbance 10. I imagine that waves 1-9 came and went without much chance of development, so no discussions were issued.

I am no expert but I have heard my husband talking about numbering wave sets,
It seem that if you count seven waves a set of three come after number one is higher than the previous
seven two is a bit higher then wham three is the huge one that they call the ten,

So by watching the set of seven and the size it can be calculated how high the ten will be.
Being a skipper you need to take notice of the sets to know when to turn your boat to avoid getting into
trouble.

Of course the sets can come in different numbers apparently depending on what part of the ocean you are
in and the depth of the sea shelf below.

I think I got it right I will check with my husband later he is in hospital at the moment so I don't want to bother
him with it right now.
Sandra

sans wrote:I am no expert but I have heard my husband talking about numbering wave sets,
It seem that if you count seven waves a set of three come after number one is higher than the previous
seven two is a bit higher then wham three is the huge one that they call the ten,

So by watching the set of seven and the size it can be calculated how high the ten will be.
Being a skipper you need to take notice of the sets to know when to turn your boat to avoid getting into
trouble.

Of course the sets can come in different numbers apparently depending on what part of the ocean you are
in and the depth of the sea shelf below.

I think I got it right I will check with my husband later he is in hospital at the moment so I don't want to bother
him with it right now.
Sandra

Sandra, we're talking about African Easterly Waves, not oceanic waves. These are waves of low pressure in the atmosphere that track westward across Africa and then across the Tropical Atlantic Basin. The waves are often the source of tropical cyclone development.