Comment Nicole hit East Florida early Thursday as the nation’s first November hurricane in 37 years, and although it’s now well away from warm ocean waters, it’s not done yet. The remnants of the tropical cyclone will carry a band of heavy rainfall from the southeastern United States into Canada, while contributing to a rare late-season tornado threat for parts of the Mid-Atlantic. Florida’s recurring hurricane tracks are surprising forecasters All tropical storm, hurricane and thunderstorm warnings have been canceled, the system is dissipating into a tropical depression – a remnant low-pressure vortex. Now the concern is shifting to the risk of hurricanes in the Mid-Atlantic. A tornado watch was issued for much of the Carolina Coastal Plain and the Piedmont, as well as southeastern Virginia, until 3 p.m. Eastern time. Additional watches will likely be lifted into the evening. Nicole officially made landfall near Vero Beach, Florida, around 3 a.m. Thursday as a Category 1 hurricane with sustained winds of 75 mph. As the storm made landfall, it unleashed peak gusts of 84 and 80 mph near Daytona Beach and Melbourne. An elevated weather station at Cape Canaveral, 120 feet off the ground, recorded a gust of 100 mph. As of Thursday morning, up to 350,000 customers in the Sunshine State had lost power, but PowerOutage.us reports that service had been restored to all but 40,000 customers as of Friday morning. A storm surge, or rise of ocean water above normal dry land, by 3 to 4 feet caused minor to moderate flooding along Florida’s Atlantic-facing coastline, but erosion from large pounding waves proved to be a bigger problem. At least a dozen structures in Daytona Beach were rendered uninhabitable as angry seas washed over the cliffs on which they were perched. The storm dumped about 3 to 6 inches of rain in eastern and northern Florida. From 10 am EST on Friday morning, Nicole was a tropical depression with maximum sustained winds of 30 mph. Centered 35 miles north of Atlanta, it was zipping to the north-northeast at 23 mph. Nicole’s atmospheric pressure was rising as the low pressure center “filled” with air. It’s similar to how a stirred mess in your morning cup of coffee eventually slows you down and the dip in the liquid levels off. Because of this, there is not as much gradient or change in air pressure with distance to support strong winds. Therefore all winds associated with Nicole are below tropical storm strength. Is it like a sled? you will accelerate faster if the incline or decline is greater and the hill is steeper. As Nicole’s inclination weakens, her winds decrease. That said, it’s still a moisture blob working northeast, and an unusually warm, moist air mass is moving north in front of it. Dew points in the mid to upper 60s will shoot as far north as the Mason-Dixon line, setting the stage for some dangerous thunderstorms Friday afternoon. Dry air is entering Nicole’s circulation from the west, the same direction from which a cold front was approaching. This influx of dry air is a blessing and a curse: On the one hand, it erodes Nicole’s circulation from the inside out and accelerates the death of her core. On the other hand, this dry air helps to suck up the warm, moist air ahead of Nicole, creating strong to intense thunderstorms. These storms will form in a particularly “rested” atmosphere. In other words, Nicole causes a change in wind speed and/or steering height. This will encourage downpours and storms to rotate and maybe even spawn a few tornadoes. The Storm Prediction Center has flagged a Level 2 out of 5 severe weather risk to account for this possibility. Charlotte, Raleigh, Richmond, Virginia Beach and Wilmington, NC are included. A level 1 out of 5 marginal risk includes Charleston and Columbia, SC DC, Baltimore and Philadelphia present a little more uncertainty. They’re also in the Level 1 danger zone. That’s because they’re facing a classic HSLC, or High Shear Low Cape, setup — extremely difficult for forecasters to predict. On the one hand, the wind dynamics strongly support rotating storms and the tornado threat. Instead, the volatility or fuel for storms will be rather limited. Exactly how these ingredients are combined, and in what proportion, remains to be seen. Nicole will compete in the DC area on Friday, with showers and possible tornadoes Inactive and inactive, storms will continue throughout Friday afternoon and evening. Additional tornado watches are likely to be needed to accommodate this potential, especially in Virginia, during the evening. More targeted warnings will be issued locally if forecasters suspect a tornado is imminent or occurring. Isolated flooding, urban and minor flooding will be possible today in the southern and central Appalachians. Heavy rain and isolated flash flooding will extend north through parts of Ohio, Pennsylvania, New York and New England tonight through Saturday. pic.twitter.com/mNpDvtMSTS — National Weather Service (@NWS) November 11, 2022 This tornado risk occurs in the “warm sector” of the storm. In the west, temperatures won’t be as warm, but the approaching cold front will help focus Nicole’s moisture and pull it out of the air – analogous to wringing out a towel. It looks like the bulk of the heaviest precipitation will be west of the Acela corridor and Interstate 95, leaving places like DC, Philadelphia, New York and Boston walking a nice tightrope. Significantly higher rainfall will fall in the west, with a broad 2 to 3 inches over the Appalachians. In the east, only a quarter to a half inch will fall near the coast. The heaviest rainfall totals will accompany “upflow” over western North Carolina, or where air is forced up into the mountains. This will drop up to 6 inches on the eastern slopes of the southern Blue Ridge. “Isolated, urban and minor flooding will be possible today in the southern and central Appalachians, particularly in the Blue Ridge Mountains,” the National Hurricane Center wrote. “Heavy rainfall and isolated flash flooding will extend north through eastern Ohio, west-central Pennsylvania, western New York and northern New England tonight into Saturday.”
