From Jonathan Vigh:
Tropical Depression Gaston, already a prolific rain producer, went out with a bang last evening. As the storm ciruculation slowly pinwheeled across southeast Virginia, a massive convective blowup developed on the circulation's northwest side. The resulting cloudburst dropped up to 4.5" of rain in an hour over and near downtown Richmond, VA. A total of 5-12" fell in just several hours across the city. The resulting flood turned downtown Richmond into a raging, muddy rapids. Hundreds of cars floated away and a 20-block district of the city was submerged. Unfortunately, at least 5 people were killed. As the system moved on, a ship in the Chesapeake Bay reported tropical storm force winds and the system was upgraded back to a tropical storm. Meanwhile, the detached low level circulation of Hermine was racing northward toward Massachussetts. Hermine made landfall at about 2 AM this morning, bringing only some 20-25 kt southerly breezes into the area and some thunderstorms. This was a much less significant event than the cold front and storms which had drenched parts of New York and Vermont earlier. This afternoon, Tropical Storm Gaston moved passed Nantucket. It's circulation is much more substantial than Hermine, but the storm is mainly a marine interest. Most of the rain has finally ended across New England and Gaston is headed for Nova Scotia and beyond, and will likely soon become extratropical. Hurricane Frances passed just 145 miles of San Juan, Puerto Rico this afternoon. The storm passed the Leeward Islands overnight, but there were few if any reports of tropical storm force winds. Saint Thomas reported a gust to 32 kt as the outer rainbands passed by, and Puerto Rico is experiencing similar conditions. The latest recon aircraft reported an spectacular stadium effect in Frances' 26 nm diameter eye and an extrapolated a central pressure of 938 mb. The eye is getting warmer with time, a sign that usually points to more strengthening, or at the very least, a mature hurricane. Frances underwent at least one eyewall cycle in the last day, and overnight, the inner eye disintegrated, leaving the current eye which has since contracted from 35 nm to 26 nm. The appearance on satellite imagery is nothing short of awesome. Mesovortices have been seen whipping around in the lower part of the eye. Frances looks a lot like Isabel in some regards, but is not as strong . . . yet. For comparison, here is a list of the Atlantic hurricanes over the past 5 years which reached a peak intensity equal to or higher than Frances' current intensity (this is in no way exhaustive or even guaranteed to be accurate): 2004 Frances(so far) 120 kt 938 mb 2004 Charley 125 kt 941 mb ------------------------------------------ 2003 Isabel 145 kt 915 mb (est.) 2003 Fabian 125 kt 939 mb ------------------------------------------ 2002 Lili 120 kt 940 mb ------------------------------------------ 2001 Michelle 120 kt 934 mb 2001 Iris 125 kt 948 mb ------------------------------------------ 2000 Keith 120 kt 941 mb 2000 Isaac 120 kt 943 mb ------------------------------------------ 1999 Lenny 130 kt 933 mb 1999 Gert 130 kt 930 mb 1999 Floyd 135 kt 921 mb 1999 Cindy 125 kt 942 mb 1999 Bret 125 kt 944 mb In summary, over 5 seasons (not counting 2004), there were 12 hurricanes that were at least as strong as Frances (this is well above the long-term average), an average of more than 2 per year. Only 4 storms reached 130 kt and above -- storms this strong are pretty rare. Frances may reach this level in the next day or two, as there are few negative factors to prevent further strengthening. An upper low is spinning to the west over the Bahamas -- this could crimp Frances outflow and even shear the system in a couple days. It is more likely that Frances will nudge this system and interact a bit, but probably not enough to cause substantial weakening. Frances' strongest inhibition to further intensification might be internal dynamics (eyewall cycles), but the storm is just as likely to strengthen as weaken in that regard. Regardless of the exact strength, a severe hurricane is headed towards the U.S. East Coast and is not likely to weaken to anything less than a major hurricane. Potential landfall could be as soon as 4 days from now (Saturday) or possibly as late as Sunday or early Monday. It is still not possible to pinpoint the landfall location (or even the state of landfall!), but the general risk area stretches all the way from Key West to Cape Hattaras. Right now, the middle of that area, stretching from West Palm Beach, FL to Brunswick, GA, probably has the highest chance of seeing the major effects from Frances. Parts of the Bahamas will likely be hit beforehand, and are currently under Hurricane Watches and Warnings. At 21Z, Frances was at 20.5N 65.9W and moving a little faster towards the west at 15 kt with maximum sustained winds of 120 kt.
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