Anticosti Vortices

In eastern Canada, the large island of Anticosti lies between the mouth of the St. Lawrence River and the main part of St. Lawrence Bay. In both visible and infrared satellite imagery today, two mesoscale cyclonic vortices have been remarkably persistent approximately south of the eastern and western tips of Anticosti Island.

The high-resolution MODIS satellite data provides a beautiful close-up view of the vortices.

The surface analysis from NOAA NCEP Hydrological Prediction Center shows generally weak easterly flow over the region, ahead of a weak warm front.

Looking at the nearby radiosonde sounding from Sept-Iles reveals an inversion layer with northeasterly flow below about 950 hPa (600 m), with shear to northwesterly flow above. Although the highest elevation on Anticosti is around 300 m, it is likely that the island itself is largely responsible for deflecting the flow sufficiently to form these nearly stationary vortices.

Nadine, Norman, and Tropical Plume Impacts

Although we have gone a while now without any direct threat of 'tropical' weather in the mainland United States, there are a couple of interesting cases currently unfolding. Far out in the Atlantic Ocean, Nadine has again strengthened to hurricane strength. This indecisive storm has been wandering around since September 11. Although initially following a reasonable mid-oceanic track, it has behaved more erratically over the last 10 days or so. Not only did it suddenly swerve away from the Azores, but it transitioned briefly to a subtropical storm, then a post-tropical storm, before again becoming a tropical storm. After looping and zigzagging its way back westward, it has just now again become a hurricane.

Looking toward the Pacific basin, Miriam dissipated to a remnant low last night west of Baja California, while just to the east of Baja a new storm formed, Tropical Storm Norman. Although Miriam swerved west instead of making landfall in Baja California and Norman is doomed to a very short existence by its proximity to land, the two storms may actually have a significant impact . . . on Texas. As occasionally happens with Pacific hurricanes, the tropical moisture that they have transported up into the mid and upper troposphere is being transported northeastward across the plateaus and mountains of northern Mexico into south and west Texas. Such 'tropical plumes' have been responsible for some of the most devastating flash flood events in the Texas Hill Country. Accordingly, the National Weather Service is warning of the possibility of widespread rainfall in South Texas that may be as high as 8 inches locally.

To add to the intrigue, the numerical model guidance gives good reason to expect that some of the mid-level circulation/vorticity from Norman will make it across Mexico over the weekend and then help to intensify the approaching shortwave trough. The resulting cyclogenesis will then produce a distinct surface low in the northwestern Gulf of Mexico. This is one of the relatively rare scenarios to bring significant widespread rain over Mississippi and surrounding states in October. Since this will be forming in conjunction with a mid-latitude shortwave trough and a weak pre-existing surface front, there is very little reason to think that the Gulf low could attain 'tropical' characteristics. (In the extremely rare cases when tropical storms do move from the Pacific into the Atlantic basin while maintaining their tropical character, they receive a new Atlantic name instead of keeping their Pacific one.)

Xynthia

A very strong midlatitude cyclone roars ashore in western Europe. The storm has been nicknamed "Xynthia". Over 50 people are known to have died so far from flooding and hurricane-force winds.

Slow Recovery from Ice Storm

The ice storm on January 26-27 that crippled much of the middle part of the country is still not over for many residents. Two weeks later there are still more than 50,000 people without electricity. In the Bootheel of southern Missouri, it may still be another two weeks before power is fully restored.

Snowstorm in England

Southern England (in particular London) is recovering from a rare heavy snow yesterday that largely shut down transportation. Because of the rarity of significant winter weather, preparations were of course not what would have been done in a colder place. The approximately 10 inches accumulation is the greatest since 1991.

Hurricane Season Wrap-Up

Finally, a news story to remind us about the huge clean-up problems still remaining from hurricanes Dolly, Gustav, and Ike. Lots of questions, no easy answers. Certainly it was another rough year for Texas (not to mention Cuba).

A High Tide in a Low City

Residents of Venice, Italy dealt with widespread flooding from the sea yesterday. Strong winds helped to raise the sea to its highest level since 1986. Although parts of the city are perennially submerged and served by water buses and gondolas, the rise of waters to about 5 feet above normal exceeded the limits of the city's transportation system and put almost all of the city's streets under water. As the normal astronomical low tide set in later in the day, conditions rapidly returned to normal and clean-up began.