Watching the tropics- earlier than usual

A system may develop in the Atlantic this week

Invest 90L swirling away from us in the Atlantic
Invest 90L swirling away from us in the Atlantic

JACKSONVILLE, Fla. – We are watching a disorganized, swirling system of low pressure that is out over the Atlantic Ocean at 23.5°N, 69.0°W. The maximum winds are currently 35-40 mph and the minimum central pressure is 1009 mb. The maximum winds spread out to a radius of 150 nautical miles. That makes it a very weak system but we are keeping an eye on it and it drew the attention of the National Hurricane Center Sunday and they began watching the system, designating it Invest 90L.

Overnight and during the day on Monday, it became evident through satellite images that Invest 90L would not bring any direct effect to the East coast of the US. That being said, surfers are looking to the horizon for a potential bump in the swell, if the waves can make it past the bank of the Bahamas. 

Forecast models push Invest 90L to the East and then Northeast. Some models do show the potential for development as a subtropical system well offshore of the Northeast of the US, essentially a fish storm- not making landfall. 

Invest 90L is up against dry air over the system, which  usually suppresses tropical and subtropical development, but the Low is over warm water, which usually contributes to development. Over the next few days we will be watching especially for the center of the low to tighten up and intensify- that will be a sure sign of development. Another factor we always watch for is shear- which is upper level winds, if they are strong it often inhibits storm intensification by tearing the vertical structure of the Low apart. The wind shear over the Low currently will keep it from developing, but with the storm motion the forecasted shear will weaken by the mid week and may no longer be a negative factor for development. 

Should Invest 90L develop, it would be quite early- before hurricane season officially begins on June 1st. The only other tropical/subtropical system to develop this early was in 1908, according to the National Weather Service's National Hurricane Center.  If the winds reach a sustained level greater than 38mph, Invest 90L would then be named Arlene, the first name up on 2017's hurricane names. 

About the Author: