Wednesday, January 03, 2018

‘Bomb cyclone’ to blast East Coast before polar vortex uncorks tremendous cold late this week


Unforgiving cold has punished the eastern third of the United States for the past 10 days. But the most severe winter weather yet will assault the area late this week.
First, a monster storm will hammer the East Coast from north Florida to Maine with ice and snow. By Thursday, the exploding storm will, in many ways, resemble a winter hurricane, battering easternmost New England with potentially damaging winds in addition to blinding snow. Blizzard warnings have been issued for the Virginia Tidewater region and eastern Massachusetts and Maine, and could be extended to other portions along the Eastern Seaboard, under winter storm warnings.
“This rapidly intensifying East Coast storm will produce strong, damaging winds — possibly resulting in downed trees, power outages and coastal flooding,” the National Weather Service tweeted Wednesday morning.
Forecasters are expecting the storm to become a “bomb cyclone” because its pressure is predicted to fall so fast, an indicator of explosive strengthening. The storm could rank as the most intense over the waters east of New England in decades at this time of year.
National Weather Service hurricane hunter aircraft are even flying into the storm to gather data and refine the forecast given the possible severe impacts in coastal areas.
In the storm’s wake, the mother lode of numbing cold will crash south — likely to be the last but most bitter in brutal blasts since Christmas Eve in the Northeast.

The storm: How much snow and wind, and where

The responsible storm is forecast to begin taking shape off the coast of Florida on Wednesday, unloading hazardous snow and ice in highly unusual locations not accustomed to such weather.
It is then expected to rapidly intensify, buffeting the Mid-Atlantic beaches and eastern New England.
The Weather Service office serving northeast Florida and southeast Georgia warned of a heavy mix of freezing rain, sleet and snow through Wednesday afternoon. “Power outages and tree damage are likely to be due to the ice,” it said. “Travel will be dangerous and nearly impossible.”
In Tallahassee, it was snowing for the first time in 28 years Wednesday morning.
Meteorologist Eric Fisher, based in Boston, called the forecast “bananagrams” for northern Florida. “If this verifies . . . an unreal event for this part of the country,” he tweeted.
Ice and more than three inches of snow could fall in Savannah, which would make history. “In almost 150 years of record keeping, the snowiest day in Savannah is only 3.6 inches,” tweeted Greg Diamond, a meteorologist at the Weather Channel.
In Charleston, two to four inches of snow and ice is forecast Wednesday. “Travel conditions are rapidly becoming dangerous,” the Weather Service tweeted Wednesday morning. “Numerous accidents being reported and many bridges are being closed. Travel is not advised!”
The Weather Service Storm Prediction Center issued a rare alert for “heavy freezing rain” along the entire South Carolina coast Wednesday morning.
From Norfolk to the Maryland and Delaware beaches, at least 5 to 8 inches of snow is predicted, with as much as a foot possible between Wednesday evening and Thursday afternoon. Especially in the Virginia Tidewater region, under the blizzard warning, the combination of wind gusts up to 50 mph and heavy snow could cause whiteout conditions. It is only the second blizzard warning for the Virginia Tidewater since the 1980s.
Farther inland in the Mid-Atlantic, near Interstate 95, up to an inch or so could fall in Washington and Baltimore, but more in their eastern and southeastern suburbs, where several inches are predicted.
To the north, Philadelphia expects one to three inches of snow, while New York City is forecast to receive at least three to six inches late Wednesday night through Thursday.
East of Philadelphia and New York, predicted snow amounts and wind speeds increase. Atlantic City is expecting four to six inches of snow and wind gusts to 45 mph while eastern Long Island may endure six to 10 inches of snow and 50 mph gusts.
Specific amounts up and down the coast will depend on the exact storm track. If the storm tracks closer to the coast, snow amounts and peak wind gusts will be higher and extend farther west. But if the storm wobbles east, snow amounts as well as peak winds will decrease.
By the time the storm reaches the ocean waters off eastern New England on Thursday, it will have explosively intensified and become a more severe storm. Its central pressure will have fallen around 50 millibars in just 24 hours — an astonishing rate of strengthening.
“Some computer models are projecting a minimum central air pressure of below 950 millibars at its peak, which would be nearly unheard of for this part of the world outside of a hurricane,” wrote Mashable’s Andrew Freedman. “For comparison, Hurricane Sandy had a minimum central pressure of about 946 millibars when it made its left hook into New Jersey in 2012.”

It is this drop in pressure that will cause winds to really crank up in eastern New England, up to 60 to 70 mph along the coast. Winds will be considerably stronger over the ocean — exceeding hurricane force — where enormous waves will form.
In Boston, the Weather Service is forecasting up to a foot of snow Thursday, along with winds strong enough to bring down branches and cut power.
In both coastal Massachusetts and Maine, which are under blizzard warnings, the combination of potentially damaging winds and heavy snow is expected to cause whiteout conditions and significant drifting of snow.
As the wind and waves slam into the shore, coastal flooding is forecast Thursday late morning and afternoon, raising seas 2 to 2.5 feet above normal, with “moderate to major impacts,” according to the Weather Service, inundating shore roads and basements. “In a few spots, sea ice chunks may exacerbate damage,” it said.
Even though snowfall rates could reach 2 to 3 inches per hour in eastern New England, causing “extremely difficult” travel, according to the Weather Service serving Boston, it is most concerned about the power outage threat and the bitter cold predicted to follow.
The storm’s enormous circulation will help draw several lobes of the polar vortex, the zone of frigid air encircling the North Pole, over the Mid-Atlantic and Northeast by Friday and Saturday. Wicked cold air sourced from Siberia, the North Pole and Greenland will all converge on the region.
Temperatures are forecast to be 20 to 40 degrees below normal, the coldest of the winter so far.
Most locations in the Mid-Atlantic and Northeast are predicted to set records for cold temperatures Friday, with highs in the single digits and teens.
On Saturday morning, subzero cold is forecast over almost all of New England, with single digits in the Mid-Atlantic.
 Winds, gusting to 30 mph, will make these areas feel 10 to 20 degrees colder.
 Finally, after one of the most intense cold spells of such duration on record in parts of New England — including Boston — temperatures are forecast to gradually thaw by early next week.

WP







No comments:

Twitter Updates

Search This Blog

Total Pageviews