Average 18 year old weather nerd. Freshman at Plymouth State University, majoring in meteorology, with the goal of becoming a professional forecaster.
By: MAweatherboy1 , 9:13 PM GMT on September 03, 2012
Tropical Storm Leslie is the main feature being watched in the tropics right now. As of the latest advisory from the National Hurricane Center, Leslie is located about 585 miles south of Bermuda, and is crawling NNW at 3mph. Leslie currently has maximum sustained winds of 60mph and a minimum central pressure of 998mb.
Forecast for Leslie
Leslie is currently disorganized, as strong shear continues to prevent thunderstorms from consolidating over the center. Leslie has maintained a rather impressive area of deep convection for the past 24 hours, but it remains mostly to the south and east of the center. Shear is forecast to remain high for most of the next 24 hours, so strengthening in this period is unlikely. After this, however, conditions are expected to become much more conducive for development, and strengthening is likely to begin by tomorrow night. The official NHC forecast brings Leslie to 100mph in 5 days, which would make it a category 2 hurricane. I think this forecast is reasonable, though it could be slightly conservative, as I think Leslie will be around 105-110mph in 5 days. The track forecast is continuing to become more difficult as model solutions continue to diverge. The most immediate concern for land is the island of Bermuda. It is looking more and more likely that hurricane conditions will be threatening the island in 5-6 days. The official NHC forecast, seen in Figure 1, takes Leslie west of Bermuda, which would put the island on the system's east side, which is normally where the most severe conditions are found in a hurricane.
Figure 1: Official NHC forecast path for Leslie.
Residents of Bermuda should pay close attention to this storm. Beyond this time period, the forecast becomes very difficult. Some models, including the GFS, keep Leslie well clear of the East Coast of the United States, with the only impacts being large waves and rip currents. Other models, including the CMC and as of its latest run the ECMWF, bring Leslie closer to the East Coast, and indicate at least tropical storm conditions possible for New England. Most of the models indicate Leslie deepening significantly, regardless of how close to the coast it gets. I feel a solution more like that of the GFS is most likely, taking Leslie well offshore, but the overall trend has been to bring her closer, so everyone on the East Coast should keep an eye on Leslie.
Figure 2: Tropical Storm Leslie. The center is located on the very NW edge of the deep convection, indicating shear.
99L May Develop, But Won't Threaten Land
In the central Atlantic, an area of disturbed weather, Invest 99L, has been organizing today. As of their 2PM Tropical Weather Outlook, the National Hurricane Center is giving 99L a 60% chance of development in the next 48 hours. Conditions are fairly favorable for development in the short term, and I put development odds at about 70%. 99L is an extremely small system, and will be no threat to land regardless of development.
Figure 3: Invest 99L.
Disorganized John No Threat
In the East Pacific, Tropical Storm John is currently located about 290 miles WSW of the southern tip of Baja California as of the latest advisory from the National Hurricane Center. He is moving NW at 14mph. John's maximum sustained winds are estimated to be 40mph, and his minimum central pressure is 1002mb. John is being battered by high shear, as evident by his exposed low level circulation. He is also moving into cool waters, so weakening is likely, and I expect him to become a remnant low late tomorrow or tomorrow night. John is no threat to land.
Figure 4: Tropical Storm John, with a fully exposed center.
Thank you for reading! Have a great week!
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