Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 1:19 PM GMT on September 08, 2005
Long range radar out of Melbourne is showing a much more organized and symmetrical echo pattern today. Ophelia's large 50-mile wide center is surrounded on all sides by strong echoes that are slowly increasing in intensity. Satellite imagery shows a lack of deep convection only on the southeast side of the storm, the result of strong upper-level winds shearing the clouds away. This shear has been oscillating up and down the past 36 hours, and is currently between 5 and 10 knots. As long as the shear stays below 10 knots, slow but steady intensification should result. The latest Hurricane Hunter flight at 8:13 am EDT supports this--the pressure has fallen to 988 mb, and surface winds have increased to 60 mph. Ophelia should become a hurricane by tonight or tomorrow morning.
Although Tropical Storm Warnings have been hoisted for the Florida coast, Ophelia seems stuck in place and tropical storm conditions will likely stay just offshore today. Reports from NOAA buoy 41009 located 23 miles east of Cape Canaveral show winds this morning of 30 - 35 knots--just below tropical storm force. The surface wind field from this morning's NOAA Hurricane Hunter flight showed the the winds of the storm were elongated parallel to the coast, with the strongest winds northwest and southeast of the center.
Figure 1. Surface winds measured by the NOAA Hurricane Hunter aircraft's stepped frequency microwave radiometer and other sources this morning.
Doppler radar rain estimates show the heaviest rain is falling just offshore, but this will change this afternoon as the storm continues to intensify, bringing spiral rainbands over Florida that will fire off big thunderstorms. The intense afternoon heating of the ground by the hot Florida sun will contribute towards making these thunderstorms heavy rain producers.
Figure 2.Estimated rainfall from the Melbourne Doppler radar.
OK, it's time to play the "where will Ophelia go?" game. The answer: nowhere soon. Steering currents are very weak, and we can expect Ophelia to remain pretty much where she is now the next three to five days. Of course, since she is so close to the coast, just a slight drift westward would bring tropical storm conditions to the coast. However, the computer models pretty much agree that any motion the next three days is likely to be slowly north and then east. After heading east for a few days, all the models except the GFS agree that Ophelia will eventually loop back and hit the U.S. as a hurricane, perhaps even a major hurricane, seven or more days from now. The GFS takes Ophelia out to sea, but the latest NHC discussion notes that the GFS performed poorly in a similar situation with Hurricane Jeanne last year, and is probably on the wrong page this time around, too.
As far as intensity goes, water vapor satellite images show a large pool of dry air to the northwest of Ophelia. Winds at mid levels of the atmosphere are expected to blow this dry air towards Ophelia the next few days, and this should hamper her development. However, wind shear levels 3 - 5 days from now are expected to drop condsiderably, and this will aid intensification. All factors considered, Ophelia wil probably reach Category 2 status and perhaps Category 3 five days from now.
Hurricane Nate and Hurricane Maria
Nate finally got caught up in the westerly winds aloft sweeping across the North Atlantic, and is headed out to sea. Bermuda will escape with just tropical storm force winds. Maria is still a hurricane but almost dead; NHC will issue its last advisory on this storm later today.
Elsewhere in the tropical
A area of disturbed weather in the southwestern Gulf of Mexico is starting to show signs of organization. This area will have to be watched the next few days, and is likely to only threaten Mexico if it develops. The ITCA is quiet and there is nothing cooking off of the coast of Africa.
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