12:00 PM | ***Lee remains a “major” and has begun its turn to the north…significant impact possible this weekend across eastern New England/Atlantic Canada with hurricane-force winds on the table***
Paul Dorian
Hurricane-force gusts are on the table this weekend across eastern New England and Atlantic Canada as the pressure gradient associated with “Lee” will remain very intense. Map courtesy NOAA, Dr. Ryan Maue (Twitter, weathermodels.com)
Overview
Hurricane Lee remains as a “major” category 3 system and has begun its turn to the north as it becomes increasingly influenced by an upper-level trough over the Great Lakes/Ohio Valley. This turn to the north will come with gradually increasing forward speed and will bring Hurricane Lee to the west of Bermuda on Thursday where there will be tropical storm conditions. As an upper-level ridge intensifies over the NW Atlantic late in the week, Hurricane Lee may actually take a turn slightly to the left which will bring it close to southeastern New England. Hurricane Lee is then likely to become “post-tropical” as it potentially reaches coastal Maine/New Brunswick later in the weekend. Despite movement over colder waters before its landfall and a likely slight weakening in central pressure, the pressure gradient will remain intense between this powerful storm system and intensifying high pressure to the north. As a result, a significant impact is possible this weekend from eastern New England to Atlantic Canada (New Brunswick, Nova Scotia) with torrential rains and hurricane-force winds on the table.
The pressure gradient between the powerful storm system (“Lee”) and intensifying high pressure ridging to the north will be intense leading to potential hurricane-force winds across eastern New England and Atlantic Canada (Nova Scotia/New Brunswick). Map courtesy NOAA, tropicaltidbits.com
Details
At mid-day, Hurricane Lee has max sustained winds of 115 mph and has held its strength as a “major” category 3 system. The latest movement of Hurricane Lee is to the NNW at 9 mph and this forward speed should pick up on Thursday and Friday. The persistent WNW track of recent days has shifted today to more of a northerly direction as Hurricane Lee becomes increasingly influenced by an upper-level trough over the Great Lakes/Ohio Valley. This general northerly movement should take Lee to the west of Bermuda on Thursday producing tropical storm conditions on that island and it’ll then move over cooler waters as it climbs to higher latitudes.
An upper-level ridge of high pressure will intensify in coming days over the NW Atlantic and the result will be a slight turn to the left of “Lee” as it approaches coastal Maine/Atlantic Canada. This ridge will prevent any kind of a harmless trek by “Lee” out into the open waters of the North Atlantic. Map courtesy NOAA, tropicaltidbits.com
By the end of the week, the upper-level trough over the Great Lakes/Ohio Valley will weaken and an upper-level ridge of high pressure will intensify over the NW Atlantic. This ridge will indeed play a critical role in the ultimate path of Lee as it will inhibit any chance for Lee to escape harmlessly out into the open waters of the North Atlantic. Instead, Hurricane Lee may actually take a bit of a turn back to the northwest for a brief time early this weekend and this will put this powerful storm system potentially on a path for coastal Maine or Atlantic Canada.
“Lee” will move over much cooler waters as it approaches coastal Maine/Atlantic Canada this weekend, but its pressure gradient will remain intense and its impact is likely to be significant from eastern New England to New Brunswick/Nova Scotia. Map courtesy NOAA, tropicaltidbits.com
Given the expected movement of Lee over cooler waters of the Atlantic and an increase in vertical wind shear, Lee is likely to gradually weaken from its current “major” hurricane classification during the next few days. However, Hurricane Lee is a large system and it may actually grow in size as it climbs to higher latitudes with an expansion of its wind field – typical of tropical cyclones as they climb to higher latitudes and interact with “westerlies”. Whether or not Lee takes on “tropical storm” or “post tropical” status before reaching coastal Maine/Atlantic Canada this weekend, the pressure gradient will remain very intense between this powerful storm system and strong, intensifying high pressure to the north. As a result, hurricane-force winds are on the table this weekend across eastern New England and Atlantic Canada (Nova Scotia, New Brunswick). In addition, heavy rains and coastal flooding are possible and recent heavy rainfall in New England increases the chances that root systems of large trees may be more vulnerable to damage by strong winds.
A compilation of computer forecast models including GFS, Euro and UKMET track “Lee” to coastal Maine or Atlantic Canada by the weekend. Map courtesy Tomer Burg, NOAA, UKMET, ECMWF
Looking ahead, there is another tropical system in the eastern Atlantic Ocean that has the likelihood of intensifying in coming days as it treks across the tropical Atlantic. There are some signs that this system may ultimately pose a threat to New England/Northeast US, but that is all in the “speculation phase” right now and there are many days to go to iron out those details. An interesting thing to monitor in coming days will be to see if the passage of Hurricane Lee generates a “cold wake” (through upwelling) that could ultimately have an impact on this next tropical system.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
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