Hurricane Leslie looms to the south


Hurricane Leslie had 75mph winds and 987mb central pressure as of the latest official advisory from the National Hurricane Center. There was some evidence to suggest that either an eyewall replacement cycle was occurring or there was some dry air intrusion (Both slow development), either way, the storm’s core is becoming more organized and strengthening or maintenance of strength should be tomorrow’s theme.

Today, the National Hurricane Center upgraded tropical storm Leslie to a hurricane because evidence of a banding eye feature and microwave imagery supported this upgrade. Forecast models continue to predict that Leslie will pass very near or over Bermuda on Sunday – the exact location and timing are yet to be determined being that this event is still days away from coming to fruition.

Meanwhile, Bermuda is preparing, I would like to post a link to a Bernews article that outlines some of the preparations and comments regarding the storm. However, before I post it, I would like to point out a few point of contention that I have with it.

The Bermuda Weather Service is forecasting a fair 70-90mph sustained winds with gusts near 115mph for Sunday. This would be very dangerous and potentially damaging or even deadly. In addition to these strong winds, elevated surf is already occurring in Bermuda and will increase further to greater than 30ft outside the reefs this weekend. Storm surge or just over wash from the large swells will be a factor as the storm passes, particularly in areas where wind is onshore, eg. south shore during a southerly wind. This official forecast will likely change and be updated as the storm approaches and more information is made available.

1. “almost a direct hit” – this terminology is not meteorological; it is either a direct hit, indirect hit, or a strike. According to the National Hurricane Center’s glossary, a direct hit is where the storm passes close enough to a location that it delivers its strongest winds. Hurricane Leslie is expected to make a direct hit.

2. Category 2: winds between 96 and 111mph; 90mph is still a category one – I am knit picking a bit but still. Additionally, don’t focus too much on the category of the storm; intensity forecasts are still very inaccurate. Sometimes they are literally an educated guess, and discount the possibility of rapid strengthening. Additionally wind gusts, which are just as damaging as sustained winds, can be several categories higher than the sustained winds by with the categories are defined. Eg. Hurricane Fabian had sustained winds near 120mph (Category 3), but gusts were estimated near 150mph (Category 4).

3. I wish they wouldn’t report the closest point of approach within 72 hours unless the storm is supposed to pass during those 72 hours. This only leads to confusion – they say that they storm is expected to be “within 20 to 40 miles of the island early Sunday morning” but then say “Leslie’s closest point of approach to Bermuda within 72 hours (3 days) is forecast to be 146 nautical miles to the South”. If you weren’t paying attention, this could be very confusing.

4. Bermuda will not see “hurricane force winds for up to two days”. Hurricane force winds begin at 74mph and are located near and within the core of the hurricane. Leslie is expected to be moving fast enough that this will last 6-12 hours max. However, dangerous tropical storm force winds (>39mph) could last 24-36hours.

4b. They are closing the causeway when sustained winds reach 50kts. Keep in mind that you have to brace yourself to stand when sustained winds reach 25-30kts, tree damage and power outages start to occur when wind gusts reach 50kts. So when winds reach 35kts, don’t try to ride your bike across the causeway; in fact you should be hunkered down inside because dangerous squalls in the hurricane’s rain bands can come without any notice and produce locally higher wind gusts and even tornadoes.

Bernews Article.

Finally, I would like to make the point that the forecast is still relatively uncertain and should be made more certain tomorrow when steering currents become more well defined, and Hurricane Hunter information is collected and put into the forecast models tomorrow night. Each storm is different and it is impossible to accurately compare Leslie to any storm that has hit Bermuda this century. As the saying goes; Prepare for the worst and hope for the best. Preparations should be finished by Friday night, but you would probably be able to make some last minute preparations on Saturday morning.

After Leslie passes Bermuda, the extreme northeastern United States and the Canadian Maritimes (Nova Scotia, Prince Edwards Island, and Newfoundland and Labrador) need to prepare for the strongest storm since Hurricane Igor 2010.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s