What does the "L" mean for tropical waves i.e. inv

[tbstorm]

Oh and why are the numbers always in the 90s i.e. invest 94L

Thanks!

[wxman57]

"L" identifies the system as being in the North Atlantic Basin.

"E" = East Pacific
"W" = West Pacific
"C" = Central Paciruc
"L" = North Atlantic

[rainbird]

Welcome to the board - to a fellow newbie -

In addition to waxman's post and the reply from you:

Was informed by SkeetoBite and is modified to read:

The designation AL902005(90L) through AL992005(99L) are used over and over for investigation areas. The next investigation area will be AL972005 or 97L (correct me if I am wrong?). Once an investigation area is classified as a tropical depression, it gets the next permanent storm number for the year. In this case, AL232005(23L). This number stays with the the storm for eternity and is used behind the scenes for model runs, tract forecast, etc. The number stays with the sorm even after the storm reaches Tropical Storm strength and earns its name.

Appreciate waxman of you explaining "L"

[rainbird]

Correction and sorry - wxman57 - messed up your name

[jburns]

"L" identifies the system as being in the North Atlantic Basin.

"E" = East Pacific
"W" = West Pacific
"C" = Central Paciruc
"L" = North Atlantic

E=east
W=west
C=central

and

L?=North

Must be a reason. Anyone know?

[cycloneye]

Letter identifiers are assigned to the storm's basin of origin. If a storm passes over a basin boundary, the storm will maintain it's basin of origin letter identifier even though it has entered a new region. For example, storm "Alpha" originates in the Eastern Pacific and is assigned 01E. If it makes its way into the Central Pacific it will still maintain its number and name designation even though it is seen under the Central Pacific header.

The storm number can be an eighty series (80-89), ninety series (90-99), or a number between 1 and 50. Storms seen with a number between 80 and 89 are usually used for testing purposes only. Storms with numbers between 90 and 99 are areas that forecasters use to monitor suspect regions typically with disorganized large-scale convection that has a chance to develop into a more organized system such as a tropical depression. Storms with numbers between 1 and 50 are/were storms that reached tropical storm strength or higher.

The naming convention after the number/basin pair can be called INVEST, NONAME, or assigned name. All storms will start with an INVEST name. When the system becomes a tropical storm this name will change to either NONAME or assigned name. NONAME is assigned to storms which do not have an official assigned name yet. Assigned names are given to tropical storms according to the World Meteorological Organization (WMO). Typically, storms that form in the Indian Ocean north of the equator will have NONAME. There are a few occasions where a tropical storm name will have an INVEST or a ONE, TWO,... following the number/basin pair. This name is only temporary and typically lasts for only a couple of hours. This is caused by the timing of the position updates generated by the Automated Tropical Cyclone Forecasting (ATCF) system and when forecasters determine that the system has become a tropical storm.

Above is a little more detailed explanation about the letters and how the invests work.And welcome to storm2k.

[rainbird]

Thank you for the additional information - interesting -

[WeatherWiseGuy]

Thanks tbstorm for asking that question. I had often wondered about it myself. And thanks to all who answered.

[senorpepr]

"L" identifies the system as being in the North Atlantic Basin.

"E" = East Pacific
"W" = West Pacific
"C" = Central Paciruc
"L" = North Atlantic

E=east
W=west
C=central

and

L?=North

Must be a reason. Anyone know?

Well, E, W, and C are for EPAC, WPAC, and CPAC, respectively.

A is used for the Arabian Sea
B is used for the Bay of Bengal
P is used by the JTWC for the SPAC.
S is used by the JTWC for the S Indian.
SW Indian officially uses M (Meteo France)
SE Indian and SW Pacific officially uses U (aUstralia)
SPAC uses F (Fiji)

L is for atLantic.
Although in some cases T is used for the South Atlantic and M is used for the Mediterrenean.

[Tampa Bay Hurricane]

Thanks Mets and all for the great information

[arkess7]

thanks for the info......i knew alot of it but you learn something new everyday!!

[jburns]

"L" identifies the system as being in the North Atlantic Basin.

"E" = East Pacific
"W" = West Pacific
"C" = Central Paciruc
"L" = North Atlantic

E=east
W=west
C=central

and

L?=North

Must be a reason. Anyone know?

Well, E, W, and C are for EPAC, WPAC, and CPAC, respectively.

A is used for the Arabian Sea
B is used for the Bay of Bengal
P is used by the JTWC for the SPAC.
S is used by the JTWC for the S Indian.
SW Indian officially uses M (Meteo France)
SE Indian and SW Pacific officially uses U (aUstralia)
SPAC uses F (Fiji)

L is for atLantic.
Although in some cases T is used for the South Atlantic and M is used for the Mediterrenean.

Thanks. That explains it all very well.

[Tampa Bay Hurricane]

I wonder how many invests occur per year in the atlantic relative
to the number of TDs per year

[tbstorm]

Thanks for the info ... always wondered where the numbers came from.

Actually I have been a 'lurker' on the board for a while. finally decided to register. . . lots of very interesting conversation!

[senorpepr]

Thanks for the info ... always wondered where the numbers came from.

Actually I have been a 'lurker' on the board for a while. finally decided to register. . . lots of very interesting conversation!

It's great to have you here. If you ever have any additional questions, feel free to ask. This forum has a wealth of knowledge and we're usually willing to dispense it. Plus... others may have the same question as you or may not have thought of that question, but are curious.

[Brent]

I wonder how many invests occur per year in the atlantic relative
to the number of TDs per year

Not sure. I think this year we've had 40-50 invests(I know we've had 3 or 4 of each number already), and 22 TD's... so half or so... but this hasn't been a normal year.