Invest 91L has formed: Will it develop?

Article information and forecast thoughts as of  15:30Z on June 2nd

91L currently is located at 19.6*N 94.5*W, with maximum winds of 25mph, and a pressure of 1007mb.

Invest 91L has formed in the north Atlantic ocean and has shown positive signs for development over the past couple of days. The system has slowly become more and more organized throughout this time period. 91L is expected to make landfall in Mexico within the next 48-60 hours. This is the time it has remaining to develop. This storm has a 60% chance of becoming a tropical depression or stronger according to the National Hurricane Center in their two and 5-day outlooks.

Official NHC outlook as of 8:00 AM EDT

My forecast:
As 91L moves towards Mexico over the next 48-60 hours, I give the system a 60% chance of becoming a tropical depression as well. Given favorable sea surface temperatures as well as the moist air that the storm is surrounded by, it’s environment supports further organization of the invest. The largest inhibiting factor for the storm though is wind shear which is growing less and less favorable for the storm with time. There is currently a northern bias of convection which is where the wind shear is, meaning that unless with the heating of the atmosphere today the southern side of the storm has convection, the invest will not develop. Given the latest observations from satellite imagery the southern side does look to have some convection, the question is if that will last. The ECMWF and HWRF support a strong tropical low/tropical depression forming as the storm moves into Mexico with the HWRF showing the possibility of a tropical storm as the system moves off the coast of Mexico in 84-96 hours, although the GFS shows the low dying away and the storm not developing. As the situation progresses with 91L, Force Thirteen will produce updates on it’s YouTube channel if necessary, and the National Hurricane Center( will issue tropical weather outlooks every 6 hours regarding this invest.

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Candy Martis
4 months ago

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