Blizzard and Winter Storm Warnings issued by the National Weather Service continue to be expanded across a broad area as an unusually potent bomb cyclone unfolds. This projected intense area of low pressure moving through the Great Lakes region will create travel troubles across a large area from Minnesota to Maine, from Missouri to New Jersey, and New York down to Virginia. A variety of precipitation types, very strong winds, and coastal flooding will become a big issue between tonight and Christmas Eve night.
Perhaps one of the biggest impacts from this bomb cyclone will be the bitter cold and life-threatening wind chills that’ll rotate in behind the storm system, quickly dropping temperatures by tens of degrees in a very short period of time. Such a drastic cool-down could lead to a flash freeze scenario in which any untreated wet surface will quickly turn to ice, making travel extraordinarily hazardous.
A meteorological process known as explosive cyclogenesis will create a bomb cyclone, which is an area of intense low pressure which drops significantly over a short period of time. Generally, an area of low pressure must drop by more than 24 mb in a 24 hour period, although the criteria changes at different latitudes. Bomb cyclones are common over the Pacific Ocean, especially the North Pacific near Alaska, and will sometimes form in the Atlantic from time to time; they could happen on land sometimes too, although it’s very rare. And it looks like such a rare scenario is about to unfold over the coming days. Some computer forecast models suggest that surface pressure could collapse by as much as 40 mb over a 24 hour period.
The dangerous and record-breaking cold air mass in the wake of strong arctic cold front diving southward across the central Plains today will push into the southern Plains by late Thursday. Behind the front, temperatures across the Intermountain West and northern High Plains have plummeted 25 – 35 degrees in just a few hours, with widespread minus 10 to minus 20 readings across the region. This, combined with sustained winds of 20 – 30 mph and higher wind gusts of up to 60 mph, have and will continue to lead to wind chills as low as -40 degrees across a large swath of the Intermountain West and northern and central Plains, with more localized areas of -50 to -70 possible through the end of the week.
Wind chills of this magnitude can cause frostbite in less than 5 minutes if precautions are not taken, with hypothermia and death also possible from prolonged exposure to the cold. Livestock interests will also be severely impacted and dangers could be exacerbated if power outages occur. Consequently, widespread Wind Chill Warnings have been issued for areas spanning from eastern Washington State, through the Intermountain West, central/northern Plains, and Tennessee Valley, with additional Wind Chill Watches and Advisories covering areas as far south as the southern Plains and Gulf Coast.
As the Arctic front dives southward through the overnight hours and Thursday, daytime temperatures across the central Plains will struggle to get above 0 degrees, while areas further south in Texas and the Gulf Coast will experience temperatures in the single digits and teens Thursday evening. Furthermore, snow squalls, or a brief burst of moderate to heavy snow for an hour or two , are likely to occur immediately behind the
arctic front from the Intermountain West, to the central Plains, Ohio Valley, Mid-Atlantic, and Northeast. Developing snow squalls could lead to extremely hazardous travel conditions at times, as they will be accompanied by gusts to 40 mph, potentially creating sudden whiteout conditions.
It looks like the jet stream is going to flex its muscle and knock out the Northeast and Mid Atlantic with brutal cold air for Christmas Eve. 💪 pic.twitter.com/FZ92g8qDUu
— the Weatherboy (@theWeatherboy) December 21, 2022
Another hazardous facet of the system will be a deepening low-pressure center that forms along the frontal boundary this evening and rapidly strengthens as it tracks eastward across the Midwest and Great Lakes on Thursday. This storm system is likely to produce widespread light-to-moderate snowfall from the Midwest to the Great Lakes and Interior Northeast, with a brief burst of snow also possible into the Ohio/Tennessee Valleys and northern Mid-Atlantic immediately following the cold frontal passage.
The heaviest snowfall, with amounts potentially exceeding a foot, is anticipated to occur over the Great Lakes between tonight and Friday, especially along westward and northward-facing lakefronts, as lake-enhanced snowfall along with moisture wrapped around the low will help aid in the locally heavy totals. Combined with the snowfall, very strong winds will also accompany the system as a very tight pressure gradient develops between the low over the Great Lakes and the strong high-pressure system over the northern Plains. Heavy snowfall rates of 1-2″/hour, along with wind gusts of over 50 mph will result in near-zero visibility and considerable blowing and drifting of snow. This will lead to dangerous, to at times impossible, land and air travel leading up to the holiday weekend. The combination of heavy snow and strong wind gusts could lead to significant infrastructure impacts, including scattered tree damage and power outages.
People in the path of this bomb cyclone are advised to make final preparations as soon as possible and check on family and friends during the storm in case of an emergency.
Further east, in the warm sector of the strengthening storm system, moisture surging northward ahead of a center of low-pressure and associated coastal boundary situated off the Southeast coast will lead to moderate to heavy rainfall across the Southeast and Mid-Atlantic on Thursday with rainfall totals of 1-3″ possible. As the low-pressure system tracks northward Thursday evening, strong southerly winds ahead of the center of low pressure, combined with the new moon-tide cycle, may lead to dangerous coastal flooding from northern New Jersey to northeast Massachusetts.
Furthermore, heavy rain over a fresh snowpack could also create scattered flooding concerns for parts of Vermont and Maine on Friday, which has prompted a Slight Risk (level 2 out of 4) of Excessive Rainfall to be issued.
…he may be needed for the Pennsylvania Turnpike, the New Jersey Turnpike, the Gardenstate Parkway, and the New York Thruway if the flash freeze forecast verifies…#PAwx #NJwx #NYwx https://t.co/bxhjAWHqZA
— the Weatherboy (@theWeatherboy) December 21, 2022
Lastly, at the leading edge of the northward surging moisture over the Mid-Atlantic during the first half of the day on Thursday, light freezing rain and locally heavy snowfall could impact parts of the central Appalachians. A lingering cold air damming environment will likely keep this brief punch of wintry weather confined to the higher terrain and near the Blue Ridge mountains, but could still lead to snowfall totals of up to six inches in some spots. Moreover, on Friday, as the arctic cold front races eastward across the Mid-Atlantic and Northeast, temperatures will plunge from the mid-to-upper 50s to the 10s and 20s in a matter of hours, which could lead to a rapid flash freeze of wet pavement and surfaces from antecedent rainfall.
While the eastern part of the United States is bracing for the impacts from this storm, Hawaii is recovering. Energy associated with this blossoming system across the Mainland was responsible for a potent winter storm that brought blizzard conditions to Big Island of Hawaii summits while heavy rains and flash floods battered the lower elevation hills and beach communities around the tropical islands throughout the state. While snowplows are still working on re-opening roads around Mauna Kea on Hawaii Island, tourists and residents are enjoying the warm sunshine at the coast while snow-capped mountains stand tall in the background.
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