MAweatherboy1's Blog

Invest 90E May Develop, But No Threat To Land

Posted by: MAweatherboy1, 11:35 PM GMT on May 14, 2013

Happy East Pacific Hurricane Season! Indeed, in just hours, the first official tropical weather outlook for the Eastern North Pacific basin will be issued by the National Hurricane Center, officially beginning the season which runs from May 15-Nov 30. The East Pacific couldn't quite wait for the start of its season, however, as yesterday the first invest of the season, 90E, formed. This is certainly an exciting moment, as it is a strong sign that Atlantic Hurricane Season is also soon to be upon us. Invest 90E is currently located about 650 miles south of Acapulco, Mexico, and is drifting WNW, away from land, at 10-15mph. This general motion should continue for at least the next 3 days.

Figure 1: Invest 90E.

Satellite imagery reveals that 90E is a very typical, slowly organizing East Pacific invest. It has managed to establish itself as a separate entity from the intertropical convergence zone, which is always an early and important step in determining whether or not an invest will develop. The system has also managed to maintain convection for an extended period of time, and while the convection overall is not quite as strong as it was yesterday, it is definitely better organized, as 90E looks much more like a tropical system now than it did 24 hours ago. The latest (18z) update from the ATCF indicates that 90E is estimate to have maximum winds of close to 30mph and a minimum pressure of 1007mb. As of their 12:45 PM PDT Special Tropical Weather Outlook, the National Hurricane Center is giving 90E a 30% chance of developing within the next 48 hours. 90E is in an environment that is generally conducive to organization, with the SHIPS intensity model showing 90E traveling through less than 10kts of shear for the next three days, and a moist enough atmosphere for development. I am giving 90E a 40% chance of developing into a tropical cyclone within 48 hours, and a 70% chance within 96 hours. The GFS, CMC, and NAVGEM models all show some sort of development of 90E within 72 hours, while the ECMWF model, generally considered the world's best major global model, does not show development. This can likely be attributed to the glaring weakness of this model, which is forecasting tropical cyclogenesis. Because of the tendency of this model to not accurately capture development (such as for Cyclone Mahasen in the Bay of Bengal) I have mostly discounted its solution, as I believe 90E will develop into the East Pacific's first tropical depression, and possibly tropical storm, of the year. Should 90E strengthen to tropical storm status, it will be given the name "Alvin." My forecast for the system is below. This is meant to cover a period of about 5 days at a steady speed. The track forecast is based off a blend of the more northerly/easterly GFS, which never gets the system to 120W, and the more southerly/westerly CMC and NAVGEM, which do bring it to and past 120W. Intensity is less aggressive than models like the SHIPS (which brings 90E to 60kts in 72 hours) and GFS, but more aggressive than the NAVGEM and obviously the ECMWF which doesn't show development. I think this will become the basin's first named storm of the year.

Figure 2: My forecast track and intensity for 90E, not official. Map credit.

As always with invest forecasts, there is considerable uncertainty in both track and intensity, and future changes are a good bet. Still, there is no reasonable scenario that would have 90E impacting land in any way, as it should be a threat solely to marine interests, as most East Pacific storms are.

Figure 3: Recent visible image of 90E.

I hope to provide updates on 90E in the days ahead, and as I have mentioned in previous blogs I hope to provide fairly regular blog updates on Atlantic and East Pacific systems this year, though that will be tough for the next month or so as school finishes up for the year.

Thank you for reading, and I hope you enjoy the rest of your week.

MAweatherboy1

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Invests Organizing in the Indian Ocean

Posted by: MAweatherboy1, 9:32 PM GMT on May 06, 2013

As we begin this new week, there has been little change in the global tropics over the past few days. The focus for potential tropical development continues to be on the Indian Ocean, both the northern and southern part of the basin. The more imminent threat for development is in the southern Indian Ocean, where an area of low pressure at low latitude (less than 5 degrees) and far from land is organizing. This low is invest 94S, and is moving slowly to the SW. M...

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Two Indian Ocean Cyclones Likely to Develop Soon

Posted by: MAweatherboy1, 12:36 PM GMT on May 04, 2013

We are now less than one month from the start of the 2013 Atlantic Hurricane Season, and less than two weeks away from the start of the Eastern North Pacific season. Both of these basins are currently quiet, however, with no development expected for at least the next 10 days. That is not the case in the Indian Ocean, however, as favorable atmospheric conditions, including a solid MJO pulse, are likely to lead to at least two cyclones forming in the next 5 days, wi...

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Imelda Organizing, Likely to Strengthen Further

Posted by: MAweatherboy1, 10:50 PM GMT on April 08, 2013

After a lengthy stretch of quite in the global tropics, there has been one tropical cyclone active for the past few days, Cyclone 21S in the Southern Indian Ocean, which has been officially named as Imelda. As of the 5PM EDT advisory from the Joint Typhoon Warning Center, Imelda is currently located about 755 nautical miles NE of La Reunion island, and is moving west at 9kts. The system's maximum 1 minute sustained winds are estimated to be 45kts by JTWC, or about...

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Invest 93S Could Become Powerful Cyclone

Posted by: MAweatherboy1, 9:51 PM GMT on April 05, 2013

The tropics have been very quiet worldwide in recent weeks. We remain in the offseason of the Atlantic and East Pacific basins (though we grow closer every day!), and the West Pacific, South Pacific, and South Indian basins have been very quiet. This is likely to change in the coming days thanks to organizing invest 93S in the Southern Indian Ocean. This invest is currently located at approximately 11S and 74E, with the closest land area being the island of Diego...

Updated: 1:44 AM GMT on April 06, 2013

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