Monday, October 10, 2005

Hello, Columbus


Some peeks of sunshine through the clouds have pushed temperatures in the Washington DC metro area above the most pessimistic forecasts for today. At mid afternoon, temperatures were from the upper 60s to a few readings of 70. Radar shows a broken area of showers from northwest of Charlottesville south and east to near Richmond. The clouds in our area are associated with a stationary front extending from near the Outer Banks to just offshore of Cape Cod and northward to Nova Scotia. Some weak disturbances along the front are likely to produce some rain or showers as an area of spin ("vorticity") makes its way northeastward from the lower Ohio Valley. The heaviest precipitation is likely to be to the east of the metro area. However, the high amount of moisture in the air along with a source of upper-level energy and the already saturated ground combine to produce a threat of some flooding. At this point, we are less than 1.5" away from breaking the all-time October maximum precipitation record of 8.81".

Tonight and Tomorrow

Tonight will be cloudy with lows in the upper 50s and showers or occasional rain developing by morning. Rain is likely tomorrow with highs around 63. The most likely time for precipitation is from late morning through tomorrow evening.

Tropical Beat

Vince's brief reign as a hurricane has ended; peak winds this morning were down to 45 mph as the result of northwesterly shear and cool water temperatures around 22C (72F). It is now close to being Tropically Depressed at 40 mph. Vince is the earliest 20th "named" storm by 17 days. The only other one recorded since 1851 occurred on 10/26/33. That 1933 system was a tropical storm; it was followed by a minimal tropical storm (35 kt) which formed on Nov. 15 and lasted barely 48 hours.

The other areas of activity in the Atlantic are (1) an area of showers and storms from the eastern Caribbean, across the Lesser Antilles, and into the Atlantic, and (2) a tropical wave a couple of hundred miles east of the Lesser Antilles. Neither of these appear favorable for tropical development.

Columbus' Hurricanes

Columbus' first voyage to the New World was made near the peak of hurricane season, but David Ludlum, in his classic book Early American Hurricanes 1492-1870 says, "the outstanding meteorological fact of the First Voyage is simply that no hurricanes or severe storms were encountered in the West Indies despite the fact that the fleet of three small vessels traversed an area of tropical storm activity at the season of their most frequent occurrence." Was this luck, as it is sometimes described? On the 500th anniversary of the famous voyage in 1992, 2 researchers looked at the record of known tropical storms and hurricanes from 1896 through 1989 in a paper published in the Bulletin of the American Meteorological Society. They found that only 4 times in those 104 years would the center of a storm have passed within 100 km of Columbus' fleet. Only one of those storms would have been a hurricane.

Bob Sheets and Jack Williams, in their book Hurricane Watch, describe how Columbus was not so fortunate on his later voyages. On his second trip, in 1495, Columbus and his crew became the first Europeans known to have experienced a hurricane, and 2 of his 3 ships were sunk off the coast of Hispaniola. He applied that experience on his fourth and final voyage in 1502, when he noted the signs of an approaching storm. He sent a message to the governor of the new Spanish colony requesting him to hold a fleet of 30 ships in the harbor at the capital of Santo Domingo. The ships had been preparing to sail back to Spain with cargoes of gold. He also asked permission to shelter his own four ships in port. The requests were denied because of political rivalry between the governor and Columbus, and the Spanish fleet set sail right into the path of the storm. Twenty-one of the ships sank, and 500 sailors were lost. A few of the surviving ships made it back to the damaged port of Santo Domingo; only one returned safely to Spain. Meanwhile, Columbus took shelter along the south coast of the island. Three of his ships lost their anchors, but all were able to ride out the storm safely.

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