Invest Numbering System

[StormScanWx]

I know that 90-99 are used in the Atlantic (and EPAC?) and L in the Atlantic and E in the Pacific, and W in the WPAC, so what are the other letters and there are other numbers, like isn't a test invest 80 or something?

Thanks,

SSW

[SouthFloridawx]

NOTE:
- National Hurricane Center advisories and County Emergency Management statements supersede the scatter plots referenced on this page.
- The products are intended to complement National Hurricane Center discussions, not replace them.
- These are automated products that have not been quality checked.
- If anything on these products causes confusion, ignore the entire product.

The model tracks depicted on this products are derived from products from the US National Hurricane Center, the US National Weather Service, and the United Kingdom Meteorological Office.
Text versions of these products can be found at these links:
NHC
CHG
GFDL
UKMET
The naming conventions for the scatter plot products come mainly from the text products referenced above.
- Tropical cyclones for which the National Hurricane Center issues advisories utilize numbers sequentially from 1 to 49.
- Test messages and tropical distubances which may require the National Hurricane Center to initiate advisories utilize numbers between 80 and 99.
- Tropical cyclones which are forecast to develop by the UK Met Office model utilize the number 50. The tracks of these systems appear on the scatter plots for storm 50 as well as all storms between 80 and 99.

These scatter plots are intended for use by individuals with proper training and expertise.
There are multiple potential causes of misinterpretation that include, but are not limited to, the following:
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- All models have unique biases.
- Some models utilize statistics, some utilize physics formulas, some utilize a combination of both.
- Some models perform best with weaker systems, others perform best with well-developed, purely tropical systems.
- The spread of the various model solutions can give a sense of the uncertainty associated with a particular storm track. However, some of the models are interrelated as they share the same initial analyses or the same global forecast fields. Therefore, clustering of model solutions does not necessarily indicate truely independent agreement.
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- Further information on some of the models used by the National Hurricane Center can be found at the Hurricane Research Division website.

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[WindRunner]

A is for the Arabian Sea/NW Indian Ocean.
B is for the Bay of Bengal/NE Indian Ocean.
E is for the Eastern Pacific Ocean.
F is for the Southern Pacific Ocean, east of Australia (RSMC Fiji's responsibility).
L is for the Atlantic Ocean.
P is for the SE Indian Ocean, north and west of Australia.
S is for the SW Indian Ocean, east of Africa (RSMC Reunion's responsibility).
W is for the Western Pacific Ocean.


I'm not sure of the exact boundaries for the Southern Hemisphere designations, but that's the general area designations.

South Atlantic invests (such as this years first 90L, which was in the South Atlantic) are sometimes designated other letters - I believe 90Q was used before it was redisgnated 90L. I believe some of the European met bureaus have used M for Mediterranean systems, but neither are offical WMO designators.

(I've edited a couple of times upon finding a little more info for the Southern Hemisphere systems)