12:00 PM (Thursday) | ****Lee intensifying rapidly and is likely to become a "major" hurricane later today..."cat 5" on the table…WNW path brings it to the north of the northern Leeward Islands****

Lee has strengthened into “category 2” hurricane early Thursday and is likely to attain “major” hurricane status later in the day as a “category 3” classification or even higher. Images courtesy NOAA/NESDIS

Overview

Lee is intensifying rapidly and is likely to become a “major” hurricane later in the day as a category 3 or even higher. The overall environment is very favorable for the strengthening of Lee with the relaxation of wind shear as it moves underneath an upper-level ridge and its WNW trek continues over very warm waters of the tropical Atlantic Ocean. Hurricane Lee has been on a consistent path to the WNW and that should bring it to a position north of the northern Leeward Islands this weekend. 

By early next week, the west-to-northwest path of Lee should change to a northerly direction which would reduce the chances of a direct impact on the US east coast. However, any small deviation in the timing or magnitude of this potential “turn” can have significant implications downstream. Two systems that will likely play a big role in the ultimate track of Lee are many days away from even forming. They include an upper-level trough that may develop over the Ohio Valley/eastern US later next week and an upper-level ridge that may intensify over southeastern Canada/NW Atlantic.

00Z EPS forecast map of various member storm tracks for Hurricane Lee generally agree with a near-term movement of WNW and then a turn to a more northerly direction. Map courtesy ECMWF, NCAR

Details

Hurricane Lee has max sustained winds of 105 mph (category 2) at mid-day Thursday and continues on a steady path to the west-northwest at 15 mph. It is likely that Hurricane Lee may slow down in its movement this weekend as it continues to strengthen. The intensification of Lee is likely to result in attainment of “major” hurricane classification later today (i.e., category 3 or even higher) and “category 5” is certainly on the table for this storm. Two big factors in the strengthening of Lee will be the relaxation of wind shear as it moves underneath an upper-level ridge and its continuing trek over abnormally warm waters of the tropical Atlantic of nearly 30 degrees (C).

Hurricane Lee will travel over some very warm waters of the tropical Atlantic Ocean during the next few days. Interestingly though, it may travel over a “cold wake” later next week as it reaches higher latitudes in a cooler-than-normal region that was left behind by the passage last week of Hurricane Franklin. Map courtesy NOAA, tropicaltidbits.com

Early next week, the west-to-northwest track of Lee could begin to change to more of a northerly direction. Interestingly, this change in direction and climb to higher latitudes could actually result in Lee moving over a “cold wake” left behind by the passage of Hurricane Franklin last week (due to upwelling) and this could act to weaken the storm. The potential turning of Lee would be the result of a change in steering currents from the influence of the upper-level ridge (WNW direction) to the influence of an incoming trough of low pressure (N direction). The timing and magnitude of the likely “turning” of Lee is still somewhat uncertain and what happens at this point can have big implications downstream.

All indications are that Hurricane Lee can become a powerful “major” by early Friday and this hurricane-model forecast map depicts very strong winds in the lower part of the atmosphere…fortunately, this stage of the hurricane will play out over the open waters of the Atlantic. Map courtesy NOAA, tropicaltidbits.com

The two big players in the upper atmosphere that can ultimately dictate where Lee will move include a trough of low pressure that is likely to form over the Ohio Valley/eastern US later next week and a ridge of high pressure that may develop over southeastern Canada/NW Atlantic. These systems are many days away from even forming and the upper-level trough is - at least in part - currently way upstream over the Gulf of Alaska. If the incoming upper-level trough comes into the Ohio Valley/eastern US later next week - as currently expected by most computer forecast models - then it could help to steer Hurricane Lee to the northeast and prevent it from reaching the US east coast. On the other hand, if the expected ridge over SE Canada/NW Atlantic becomes the dominate system and the upper-level trough weakens or stalls then Hurricane Lee could end up going farther to the west - potentially resulting in a direct impact somewhere along the Northeast US coastline.

For now, all interests along the Northeast US coastline and Canadian Maritime Provinces should keep a close eye on Hurricane Lee as it continues on a “long track” across the tropical Atlantic Ocean and reaches “major” hurricane status…perhaps even strengthening all the way to “category 5”. One final note, there is a trailing tropical wave over the far eastern Atlantic and it is quite likely to also reach hurricane status in coming days (would be named Margot).

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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