After plowing ashore with strong winds and a damaging storm surge exceeding six feet on Sunday, tropical depression Cristobal just won’t quit. Continued heavy rains and a few tornadoes are likely from the Missouri Valley to the Midwest on Tuesday as Cristobal’s remnant tropical circulation continues to whirl its way northward.
The unusual system could become the farthest north and west tropical system on record, set to breeze into Canada while retaining some tropical and subtropical characteristics. Eventually, Cristobal could even begin producing winds to tropical-storm-force again as it merges with another weather system and sideswipes Hudson Bay.
Flash-flood watches are blanketing an area from Missouri to northern Wisconsin, having stretched on Monday more than 1,000 miles from near the Gulf Coast to the Northern Tier.
A soaker for Central states
Cristobal’s center of circulation was located in central Missouri as of midmorning Tuesday, moving north at about 30 mph. While its precipitation shield was only a couple hundred miles across, high-altitude clouds fanning outward from the system stretched from the Upper Peninsula of Michigan to the Gulf Coast, and east toward Washington.
The storm has produced excessive rain, particularly in areas far from the center of its circulation. The heaviest rainfall totals were found 400 miles from Cristobal’s center. A total of 17.43 inches fell in Live Oak, Fla., along Interstate 10, midway between Tallahassee and Jacksonville. Fargo, Ga., picked up 11.65 inches, while White Springs, Fla., registered just above 10 inches. Amounts were highly variable given the localized nature of the heaviest rain bands.
Closer to the center, 11.04 inches was reported in Pascagoula, Miss., part of a swath that has brought a widespread 3 to 4 inches across north-central Arkansas and central Missouri.
Heavy rainfall all the way to Canada
That same strip of moderate to heavy rainfall will extend farther north Tuesday as Cristobal’s remnants make a beeline for Canada. Only a six- to 12-hour window of heavy rainfall is expected, but it will pour within that period — allowing totals to climb quickly.
Two to 4 inches of rain remain possible through late Tuesday or early Wednesday in central Missouri, eastern Iowa and the southeast corner of Minnesota. That includes cities such as Columbia and Jefferson City, Mo.; Cedar Rapids and Iowa City; and perhaps Rochester, Minn. — albeit they are in a tricky place where rain totals will fluctuate dramatically over a short distance.
Farther northeast, 1.5 to 3 inches is a safe bet for much of northwest Wisconsin, including La Crosse, and places such as Marquette in the Upper Peninsula of Michigan.
Tornado risk increases in the Midwest
Cristobal’s remnants also will bring a risk of severe weather — including tornadoes — in parts of the Midwest and much of the northern Mississippi Valley. The Storm Prediction Center has placed those areas under a Level 2 out of 5 “slight risk” for severe weather on Tuesday, where Cristobal’s changing winds with height are likely to impart some twisting force on downpours in the area. A few quick-hitting tornadoes are possible.
The greatest risk for isolated tornadoes encompasses areas between Chicago; Bowling Green, Ky.; just north of Memphis, and east of St. Louis. Tornadoes are still possible outside that zone, as well, but with a decreasing likelihood.
The system has spawned tornadoes in Florida, including a 105 mph EF1 twister that hit the Orlando metro area.
Cristobal’s final act
Even after slipping into Canada on Wednesday, Cristobal still won’t give up its fight. The intrepid storm system could exhibit some tropical or subtropical traits all the way into western Ontario as it approaches the Hudson Bay.
The gradually decaying system is slated to merge with a larger upper-level storm system in the next 24 to 36 hours, metastasizing into a sort of hybrid storm system that could intensify as it begins to derive energy from the jet stream. (Purely tropical storms get their energy from warm ocean waters.)
During this process, its winds could actually increase slightly once again. A few wind gusts stronger than 50 mph are possible along the shores of Lake Michigan, particularly in western Michigan between Muskegon and Ludington.
A few gusts over 45 mph will probably occur over the southern reaches of the Hudson Bay before the system winds down in Quebec.
A history of deadly impacts
Well before its landfall in Louisiana, Cristobal had produced deadly flooding and mudslides in Central America. After forming over the eastern Pacific on May 31 and earning the name Amanda, its remnants crossed Central America and brought extreme rainfall to parts of Mexico, Guatemala, Honduras and El Salvador. At least 30 people were killed by flooding in El Salvador, while rain totals upward of 25 inches were observed in Mexico.
During its Gulf Coast landfall, Cristobal produced a storm surge that produced significant saltwater flooding from Louisiana to Florida, with a surge of up to 6.2 feet measured in Shell Beach, La. — exceeding initial forecasts of 3 to 5 feet. Bay St. Louis, Miss., experienced a 5.7-foot surge, while water levels in nearby Pascagoula ran 4.1 feet above otherwise expected values.
Even Tampa, far from the storm center, wound up with a surge of about a foot and a half, because of the strong onshore flow of air across the eastern Gulf of Mexico. Water levels receded during much of the day on Monday.
