Forecast for Tropical Storm Leslie

This hurricane season has been rather active over the past few weeks. Another tropical system was named on Thursday: Leslie. This system has strengthened quite a bit over the past 24 hours, and is moving westward across the low latitudes of the Atlantic. Most models agree that Leslie will intensify into a weak to moderate hurricane over the next few days, curving northward into open waters. However, the latest ECMWF model is differing from the others, the same as it did in the case of Hurricane Isaac.

At 2 PM EDT Saturday, Leslie can be seen in the mid-Atlantic just east of the Lesser Antilles curving northward. At this point the Euro is in agreement with the tracking of the system.

Now here is where the ECMWF differs. The model picks up a dome of high pressure forming north of the system (circled in red) on Wednesday afternoon. This high pressure stalls Leslie in the Atlantic, allowing for it to intensify over warm waters at around 29 degrees Celsius.

As this system stalls, a surface low pressure system comes off the eastern U.S. and begins to interact with the circulation of Leslie. Due to the cyclonic flow of this new low pressure system, this interaction causes Leslie to move north-northwestward towards the upper Northeast states.

 This is the final output of the 12Z Euro run for the afternoon of Sunday, Sept. 8. Here, Leslie is a weak category 2 hurricane just off the coast of Maine. It appears after this, according to other model outputs, the storm gets caught in the jet stream, taking it back out to sea.
As one could imagine, this is a long way out, so this model will not likely hold true. However, the Euro has been the most accurate in forecasting hurricane tracks in recent years. It will be interesting to see how this plays out over the upcoming week.