Bombogenesis Ongoing

by Chris Dolce 6:49 AM Weather
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A powerful coastal storm with very strong winds and heavy rainfall is undergoing bombogenesis near the East Coast, resulting in tree damage, power outages and flooding.  

Rapid intensification of the low pressure system is ongoing near New York City, and it is expected to continue to rapidly intensify as it moves into the Hudson Valley overnight. 

Bombogenesis is a rapid deepening of pressures in a storm, which rapidly increases winds near the center of the storm. Scientifically, bombogenesis is defined as a drop of 24 millibars in 24 hours. 

So far, winds are gusting in the 30-50 mph range so far near the coasts of New Jersey, Maryland, Long Island and Massachusetts. Winds as high as 70 mph have been reported in the higher elevations of New England. These winds may increase through the late evening into the morning hours. 

One of the ingredients for this coastal storm is a powerful jet stream disturbance sweeping through the eastern states that will help induce the formation of a strong low-pressure system near or off the mid-Atlantic and Northeast coastline. This storm system is receiving an injection of moisture and energy from ex-Tropical Storm Philippe, currently tracking quickly northward to the east of this parent low pressure system, as well as the cold front sliding through the East. 


An area of low pressure will intensify in the Northeast while tapping tropical moisture on Monday. This will result in a powerful storm system that will cause wind damage and flooding rainfall.

The National Weather Service office in Boston noted in its Saturday morning discussion that this is an unusual and truly strong, potentially dangerous storm system for late October.

Rain is currently increasing across the Northeast due to the approaching cold front and tropical moisture streaming northward.

More than four inches of rain has been reported already in a few spots in New Jersey and New York. 


Current Radar and Conditions

Here's an overview of the timing and possible impacts of this storm. 

Storm Timing

Overall, this East Coast storm will be a quick-mover as it races northward on Monday.

  • Sunday night: Peak impacts from the storm begin to ramp up in the Northeast through the overnight hours, including the likelihood for damaging winds and heavy rainfall. Rain is expected to change to snow in parts of the central Appalachians, where a winter weather advisory has been issued.
  • Monday: Damaging winds and heavy rain will likely continue over parts of New England and upstate New York, at least during the first half of the day.


Monday Morning Forecast

Wind Damage Threat

High winds are likely in the Northeast overnight into early Monday, with damaging winds most likely along the coast from New Jersey to Maine. 

Numerous trees have been downed across southern New England so far. 


Wind Forecast

We expect to see wind gusts up to 70 mph in some areas, and they could be higher depending on the intensity and track of the storm. The potential for higher-end wind gusts will be greatest along the immediate coast and in higher-terrain locations, particularly in New England, where a few gusts may reach 75 mph.

Funneling of winds in between high-rise buildings and mountain and hilltops may also create locally higher winds. 

High wind warnings have been issued for New York City and Long Island and much of New England including Boston for Monday morning. High wind warnings have also been posted for parts of eastern New York and near Lake Ontario.


Current Wind Warnings

In addition, hurricane-force wind warnings have been issued for the coastal waters from eastern Massachusetts to southern Maine.

There will be three main impacts from the winds in portions of the Northeast:

  • Tree damage and power outages will be possible across the Northeast, and likely along the coast. 
  • The strong winds will likely cause delays at major airports.
  • Onshore southeast winds ahead of the storm could result in some beach erosion, along with high surf.

Power outage potential on Sunday and Monday, mainly due to expected damaging winds.

In addition to the overlying wind threat, a few waterspouts and/or tornadoes are possible in coastal Massachusetts this evening into early Monday as Philippe's energy moves through a relatively warm, moist pocket with abundant wind shear. 

Heavy Rain Potential

Given the tropical moisture tap, a large portion of the Northeast could see more than 3 inches of rainfall. Heavier totals topping 6 inches are likely. At this time, the heaviest rainfall is expected in portions of Upstate New York and in the higher elevations of New England. 


Rainfall Forecast Through Monday

The heavy rain could contribute to flooding not only in urban and poor-drainage areas, but also on streams and rivers. This concern has prompted flash flood watches to be issued by the National Weather Service for much of New England, New York, New Jersey and eastern Pennsylvania.


Flood Alerts

After a very dry start to October, the Northeast saw heavy rain this week from another storm system. Now that the ground has become more saturated, particularly in parts of New England, that will make those areas more prone to flooding through Monday.

The rain will also likely erase some of the abnormally dry and moderate drought areas on the latest U.S. Drought Monitor.

In addition to the rainfall, heavy snowfall is possible in parts of western Maryland, West Virginia and the mountains of North Carolina and Kentucky where the air is coldest. Up to 4 inches of snow is possible in central West Virginia in the highest terrain. 

Marine Impacts

As this coastal storm rapidly intensifies, waves are expected to quickly ramp up from the mid-Atlantic northward to New England. These waves will make boating extremely dangerous, and boats should stay out of the water. 

People should also stay out of the water along the coast due to these high waves and likely rip currents that will be life-threatening. 


Current wave heights

A storm surge of 1-3 feet is expected along the coast, especially on east- or southeast facing coastlines. Minor inundation is expected. 

Reports So Far

Wind: 

  • 70 mph gust at Mt. Mansfield, Vermont
  • 67 mph gust on Great Gull Island, New York
  • 67 mph gust in Westerly, Rhode Island; sustained winds of 49 mph
  • 52 mph gust near East Moriches, New York
  • 47 mph gust in Washington, DC
  • 46 mph gust near West Bolton, Vermont

Rain: 

  • 4.50 inches near Waretown, New Jersey
  • 4.07 inches in Brentwood, New York
  • 3.88 inches in Wilton, Connecticut
  • 3.84 inches near Oakville, Connecticut
  • 3.71 inches at Newark, New Jersey (Daily record)
  • 3.64 inches in Armonk, New York 
  • 3.21 inches in Harvey Cedars, New Jersey
  • 2.78 inches at JFK airport in New York City (Daily record)
  • 2.78 inches near Atlantic City, New Jersey
  • 2.75 inches near Phoenicia, New York
  • 2.73 inches in Rehoboth Beach, Delaware
  • 2.68 inches in Bridgeport, Connecticut (Daily record)
  • 2.59 inches at LaGuardia airport in New York City (Daily record)
  • 2.17 inches in Central Park, New York 
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