Extreme Temperature Diary- Saturday December 16th, 2023/Main Topic: Strong Coastal Low Forecast to Pound Atlantic Seaboard with the Absence of Snow

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The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: Strong Coastal Low Forecast to Pound Atlantic Seaboard with the Absence of Snow

Dear Diary. While I was a forecaster at the Weather Channel, I dealt with a lot of strong coastal lows that affected the Atlantic Seaboard area from December through March. If they did not track inland, they had a snow component since cold air below freezing residing inland would be drawn into each system. The storm that will be affecting the Northeast this weekend into Monday will be unusual given its track. It’s absence of snow is glaring meteorologically, which is one more sign of a changing climate:

Rain will be falling from Maine into southern Canada, which will be quite unusual given the date.

Elsewhere as of Friday snow of any consequence was not falling across the entire lower 48 state area:

Nonetheless, this system will be damaging enough, especially in Florida. I contend that warmer than average Gulf of Mexico waters will strengthen this storm more than what would have occurred in colder times from the 20th century.

I doubt that all subsequent strong storms affecting the Northeast will be snowless for the remainder of this winter, but this storm should serve as a warning that our climate is changing.

Here are more details from Matthew Cappucci writing for the Washington Post.

Strong storm set to batter East Coast this weekend and Monday – The Washington Post

Intense storm to blast area from Florida to Maine with heavy rain and strong winds

The storm begins with a tornado risk in Florida on Saturday night and will bring widespread heavy rain and strong winds along the East Coast on Sunday into Monday

By Matthew Cappucci

Updated December 16, 2023 at 12:21 p.m. EST|Published December 16, 2023 at 12:14 p.m. EST

Model simulation of storm on Sunday evening. (WeatherBell)

An unusually strong December coastal storm is set to batter the Eastern Seaboard, producing a huge swath of heavy, wind-driven rain. Strong winds, topping 60 mph in some instances, will batter coastal areas that also should expect shoreline flooding and beach erosion. The rain will be heavy enough inland to cause areas of flooding.

The moisture-loaded storm is organizing over the Gulf of Mexico on Saturday and will charge northward, progressing from the Georgia coast Sunday morning to the Mid-Atlantic coast Monday morning and to New England on Monday afternoon.

The National Weather Service is describing the storm as “intense” and “powerful.”

The system begins with the risk of tornadoes Saturday night into Sunday across the Florida Peninsula. At least some tornado risk will spread north into coastal Georgia and/or the Carolinas on Sunday.

Ordinarily, a sprawling December storm system carrying this much moisture would feature a rainy side and a snowy side. That said, there’s hardly any cold air to come by in the eastern United States, so mostly rain will fall until some snow showers wrap around on the storm’s backside Monday and Monday night in the interior Northeast and the Appalachians.

National Weather Service)

There will be a lot of rain, too ― with widespread totals of 1 to 3 inches from Florida to Maine, with locally higher amounts as the storm draws moisture from the Atlantic, the Caribbean and even the Pacific. Some areas will be bombarded by a narrow jet of particularly heavy rain, not unlike the atmospheric rivers that affect the West Coast.

Flood watches have been issued for portions of Florida, New Jersey, eastern Pennsylvania and the Delmarva Peninsula (which consists of portions of Delaware, Maryland and Virginia); those watches affect more than 20 million people. The watches probably will be expanded to many other areas along the East Coast.

Tornado risk on Saturday night according to the National Weather Service. (NOAA)

Saturday night into Sunday will yield the risk of severe thunderstorms and a few tornadoes in Florida, particularly from Gainesville and Daytona Beach southward. The center of developing low pressure will move ashore in the Big Bend or Panhandle. Winds from the east and southeast will spread over most of the peninsula, drawing inland a filament of warm, humid and unstable air — storm fuel.

That will allow thunderstorms to sprout, and some may rotate. While winds will blow from the east and southeast near the ground, they’ll be more westerly at higher altitudes.

That change of wind speed and/or direction with height, meanwhile, will cause storm clouds that span multiple layers of atmosphere to spin. That’s why concern for tornadoes exists, particularly overnight in Florida.

On Sunday, the risk of severe storms — and a somewhat lower tornado risk — will shift toward the eastern Carolinas.

Heavy rain for the East Coast

Projected rainfall through Tuesday morning from the National Weather Service. (WeatherBell)

The moisture-infused storm will unload at least 2 to 3 inches of rain over a wide band near where the storm center tracks, bringing the potential for pockets of flooding near creeks and streams and in areas of poor drainage.

After dousing Florida on Saturday night, the rain will spread over the Carolinas on Sunday morning, reaching D.C. and Baltimore by midday, Philadelphia by evening and work toward New York City on Sunday night. In most areas, rain will last for about 12 to 18 hours.

Portions of eastern South Carolina and perhaps southern North Carolina could experience some of the heaviest rain, potentially approaching 4 inches. That’s where weather models are suggesting an influx of subtropical moisture that could contribute to “potentially heavy to excessive rainfall,” according to the Weather Service. The agency notes that some computer models show the potential for rainfall rates of up to 2 inches per hour Sunday afternoon in this zone.

Strong winds

A blend of weather models simulates where winds may be strong with the upcoming system. (WeatherBell)

As the storm system intensifies while riding up the coast, it will inhale air from all sides. That vacuum effect will result in strong winds.

Gusts could hit 60 mph at the coast from the South Carolina/Georgia border north to the Gulf of Maine. A few weather models hint at gusts of up to 70 mph for the Outer Banks, Cape Cod and Downeast Maine.

Along the Interstate 95 corridor, gusts could reach 40 to 50 mph or even a bit higher in Southern New England. Some power outages could result and tree-falls are possible as heavy rain loosens soil and makes trees more susceptible to being toppled by strong gusts.

Coastal flooding

The European model simulates waves up to 60 feet tall just off the coast. (WeatherBell)

A persistent onshore flow ahead of the storm center’s arrival will pile water against the coastline. Minor to moderate coastal flooding is likely at minimum, and more-significant coastal flooding may occur if the storm tracks nearer the coast and the easterly winds are stronger.

Moderate coastal flooding with water levels up to 2 to 3.5 feet above normal is expected in Charleston, S.C., on Sunday morning, the North Carolina Outer Banks on Sunday afternoon and night, Virginia Beach on Sunday evening and parts of the Delmarva on Sunday night. This threat will spread over the Jersey Shore, Long Island and the south coast of New England on Monday.

There also will be 60-foot waves within 25 miles of the coastline for both the Outer Banks and Cape Cod. While waves that large will stay offshore, the seas undoubtedly will be churned up closer to the coast, resulting in beach erosion.

Jason Samenow contributed to this report.

By Matthew Cappucci Matthew Cappucci is a meteorologist for Capital Weather Gang. He earned a B.A. in atmospheric sciences from Harvard University in 2019, and has contributed to The Washington Post since he was 18. He is an avid storm chaser and adventurer, and covers all types of weather, climate science, and astronomy. Twitter

Here are more “ET’s” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks, as well as any extreme precipitation reports:

Here is More November 2023 Climatology:

Here is More Climate and News from Saturday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Today’s News on Sustainable Energy, Traditional Polluting Energy from Fossil Fuel, and the Green Revolution:

More from the Weather Department:

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