Saturday, August 27, 2011

Updated Hurricane Irene Impacts - Philadelphia, New Jersey, New York City, Long Island

Satellite (above) and radar (below) imagery indicate that the center of Hurricane Irene is currently located about 50 miles South/Southeast of Norfolk, Virginia and moving North/Northeast at 15 mph.  Based on the present movement, I would expect the center of Irene to move back offshore just Southeast of the Virginia/North Carolina border within 90 minutes.

According to surface, radar and aircraft reports, at 5pm EDT, maximum sustained winds were 80-85 mph, with gusts of up to 105 mph.  The minimum central pressure is 28.05 inches of mercury (950 millibars).

Conditions are already deteriorating across the Philadelphia and New Jersey areas, with widespread rain, some heavy, and gusty winds as high as 45-50 mph currently being reported in some spots (particularly around the Atlantic City and south Jersey areas).  This trend of deteriorating weather will continue into the evening hours.  Sustained winds of 30-40 mph with gusts to 50 mph can be expected to overspread the Philadelphia area between now and 7pm, and the New York City and Long Island areas by late evening.

Winds will continue to increase during the late evening and overnight hours, with the following peak wind conditions expected across the region (top values are sustained winds, bottom values are maximum expected gusts):

Please keep in mind that the above winds are forecast at the surface level.  Winds from about the 25th floor upward on high rise buildings will average 20-30% higher.

The single largest problem we've seen so far today in North Carolina, Virginia and Maryland (just as expected) has been widespread tree and power line damage.  This is aggravating an already significant threat of power outages, and similar conditions can be expected across the Philadelphia, New Jersey and New York City areas later this evening and tonight.

The total duration of the maximum winds on the graphic above is expected to range from 4-6 hours at any given location.  Less intense, but still strong, winds will be possible for an additional 2-4 hours in any given location, for a total potential of 6-10 hours of prolonged "wind stress" (i.e., 35+ mph sustained winds with gusts of 45+) across the region.

Very heavy, possibly flooding rains will also be a significant threat.  Widespread rainfall of 6-8 inches with localized amounts near one foot can be expected through tonight:

In addition to fresh water flooding, coastal flooding related to storm surge will also be a concern this evening across the region.  The sequence of images below shows the probability (see color coded percentage scale at bottom of each image) of a storm surge of 2 feet, 4 feet and 6 feet this evening and Sunday morning at the times of high tide:

Please go to this link and select the office nearest you to familiarize yourself with mandatory evacuations and specific details on storm surge flooding potential in your area.

Isolated tornadoes are also possible in association with Irene this evening and tonight.  Tropically-induced tornadoes are usually relatively weak and short lived.

If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!

1 comment:

Anonymous said...

thank you so much for your detailed reporting the last few days. we live on the island and information has been all over the place. yours has been consistent and reliable. we decided not to leave but packed an emergency kit with many of the things you suggested and at least feel as if we know what is coming our way. thank you again!

beth, riverhead long island