Olga falling apart; big 'Noreaster coming Sunday

The hurricane season of 2007 is almost over (again!) Tropical Storm Olga's passage over the rough terrain of Hispaniola has considerably disrupted the circulation of the storm, and visible satellite loops show a poorly organized circulation with a few weak rain bands removed to the north and east of the center. Radar loops out of Gran Piedra, Cuba show disorganized patches of rain impacting eastern Cuba, western Haiti, and the southeastern Bahama Islands. Puerto Rico took the brunt of Olga's rains, with amounts exceeding eight inches common (Figure 1). Satellite estimates of rainfall over Hispaniola show maximum rainfall amounts of up to four inches thus far over the northern Dominican Republic and Haiti. Additional rains of 2-4 inches from Olga may cause localized flash flooding and mudslides, but Olga will cause nowhere near the chaos that the 10-25 inches of rain from Tropical Storm Noel did in late October.

Wind shear has increased to 30 knots over Olga, and water vapor satellite imagery shows that Olga is moving into some very dry air. These influences should destroy Olga by Thursday. The remnants of Olga may still bring heavy rains of 2-4 inches to the southeast Bahamas and eastern Cuba, and 1-2 inches to Jamaica and the Cayman Islands. The 00Z runs of the GFDL and HWRF computer models foresee that Olga will regenerate on Friday and threaten the north coast of Honduras on Sunday as a Category 1 hurricane, but this solution is not supported by the other models. Given Olga's current weak condition, it is unlikely there will be enough left of the storm on Friday to regenerate into anything.


Figure 1. Precipitation estimated from the Puerto Rico radar for Tropical Storm Olga.

Major 'Noreaster coming Sunday
All of the major computer models forecast that a major winter storm will track across the Ohio Valley on Saturday, then explode into a powerful 'Noreaster Sunday off the U.S. northeast coast. Heavy snow amounts of 1-2 feet and significant ice accumulations are possible in inland regions of the Northeast. Rain appears to be the most likely type of precipitation at locations nearer the coast, such as Philadelphia, New York City, and Boston. It is too early to be confident of this forecast, since minor changes in the storm's track will greatly influence the type of precipitation. Minor to moderate coastal flooding is possible along the coast from New York City to Maine on Sunday.

Ice storm in the Midwest
I haven't found the opportunity to say much about the remarkable ice storm that has paralyzed much of Oklahoma, Kansas, Missouri, and surrounding regions this week, as I've been busy talking about Olga and trying to keep up on the latest in climate change science at the American Geophysical Union Conference here in San Francisco. The wunderphotos posted by people to the web site have been truly astounding, chilling, and beautiful, and I thank all of you who posted photos.

I'll have a update Thursday morning.

Jeff Masters