18 September 2019

Major Hurricane Humberto passing by Bermuda, Imelda flooding Texas, Jerry forms in deep tropics

The Atlantic family portrait on Wednesday afternoon. (CIRA/RAMMB)
Humberto is now a Category 3 hurricane with 120mph peak sustained winds.  As of 2pm EDT, it's centered about 100 miles west-northwest of Bermuda, tracking quickly toward the east-northeast at 20mph, and the tropical storm force winds extend an average of 175 miles from the center.  This is the second major hurricane of the season, after Dorian.  Bermuda will experience hurricane conditions on Wednesday evening/night, including 1-3 feet of storm surge and 2-4 inches of rain.  The latest version of the radar loop shown below is available at http://bmcnoldy.rsmas.miami.edu/tropics/radar/

Imelda was only a named tropical storm for a few hours, and was downgraded to a tropical depression on Tuesday evening, but the flooding threat remains very significant.  Rainfall totals over the past two days are shown below, and the forecast for the next two days is right below that.  This will be a major event (areas with over two feet) when it's all over, but the amorphous storm is crawling north at just 5mph, so it's far from over yet.

Tropical Depression 10 was upgraded to Tropical Storm Jerry early Wednesday morning, making it the 10th named storm of the season.  It is forecast to become the season's 4th hurricane on Thursday as it tracks toward the Leeward Islands.  As of Wednesday afternoon, it's centered 750 miles due east of Martinique and moving toward the west-northwest at 15mph.

The track guidance is still largely in agreement on it passing north of the Leewards on Friday as a hurricane, but tropical storm conditions could arrive in the islands by midday Friday. If the track stays on the south side of the guidance envelope, the northern Leewards could experience hurricane conditions on Friday.  Uncertainty sneaks in via a big patch of dry air to its west right now -- huge differences in forecast evolution crop up depending on it if the storm keeps itself isolated from that or if it wraps it into the circulation.
The forecast is still hazy beyond Friday or so, and that has big implications for the Greater Antilles, the Bahamas, and the southeast US next week.  As of now, about 15% of the ECMWF ensemble members do not recurve the hurricane out to sea before reaching land. And it just so happens that some of that 15% keep the storm rather strong. So, it is definitely something to keep a close eye on with each new model cycle.  The stronger Jerry stays these next few days, the more it will feel the presence of the subtropical ridge and the further south it will stay.

Elsewhere, two other waves have small chances of developing into depressions within the next five days, but considering the amount of current activity, they are not worth going into detail just yet.

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