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Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.Meteorological Bomb Brewing for Canada on Wednesday
The most powerful Nor'easter of the year will gather strength over the waters offshore of Virginia on Tuesday, then head northeast and bring damaging winds, heavy rain and snow, and a substantial storm surge to Nova Scotia and Newfoundland Canada on Wednesday. The storm will brush Cape Cod, Nantucket, and Martha's Vineyard, Massachusetts on Tuesday night and Wednesday morning, bringing at least six inches of snow and wind gusts of up to 60 mph. A Blizzard Watch and Coastal Flood Watch are posted for Cape Cod and Nantucket Island, where a NOAA storm surge model run using the winds from the 00Z run of the GFS model predicted almost a 2 foot surge could occur on Wednesday morning. A surge of this magnitude is capable of causing minor to moderate flooding.
Figure 1. Wind forecast for 5pm EDT Wednesday March 26, 2014, made from the 2am EDT Monday, March 24, 2014 run of the GFS model. Winds in excess of 50 knots (57.5 mph, pink colors) are predicted along the coasts of Nova Scotia and Newfoundland, Canada.
A Meteorological Bomb
As the storm pulls away from the Mid-Atlantic coast on Tuesday evening, it will undergo explosive deepening, meeting the criteria of a "meteorological bomb"--a storm that deepens by at least 24 mb in 24 hours. In fact, the Monday morning 00Z run of the European model shows the pressure falling by more than double that pace--deepening by an extraordinary 40 mb in just eighteen hours, ending at 2 pm EDT Wednesday. When the Nor'easter hits Nova Scotia and Newfoundland on Wednesday evening, the central pressure of the storm is expected to be between 956 - 960 mb, similar to the central pressure of a strong Category 2 hurricane. However, Nor'easters do not form eyewalls with intense winds concentrated over a small area, and this Nor'easter's strong winds will be spread out over a large area. I doubt we'll see sustained hurricane-force winds of 74 mph or greater at any land stations, but sustained winds of 60 - 70 mph are likely in some locations, which will be capable of causing widespread power outages and considerable tree damage. A storm surge of 2 - 4 feet may also cause coastal damage and moderate flooding, if the surge arrives at high tide.
Jeff Masters
Figure 1. Wind forecast for 5pm EDT Wednesday March 26, 2014, made from the 2am EDT Monday, March 24, 2014 run of the GFS model. Winds in excess of 50 knots (57.5 mph, pink colors) are predicted along the coasts of Nova Scotia and Newfoundland, Canada.
A Meteorological Bomb
As the storm pulls away from the Mid-Atlantic coast on Tuesday evening, it will undergo explosive deepening, meeting the criteria of a "meteorological bomb"--a storm that deepens by at least 24 mb in 24 hours. In fact, the Monday morning 00Z run of the European model shows the pressure falling by more than double that pace--deepening by an extraordinary 40 mb in just eighteen hours, ending at 2 pm EDT Wednesday. When the Nor'easter hits Nova Scotia and Newfoundland on Wednesday evening, the central pressure of the storm is expected to be between 956 - 960 mb, similar to the central pressure of a strong Category 2 hurricane. However, Nor'easters do not form eyewalls with intense winds concentrated over a small area, and this Nor'easter's strong winds will be spread out over a large area. I doubt we'll see sustained hurricane-force winds of 74 mph or greater at any land stations, but sustained winds of 60 - 70 mph are likely in some locations, which will be capable of causing widespread power outages and considerable tree damage. A storm surge of 2 - 4 feet may also cause coastal damage and moderate flooding, if the surge arrives at high tide.
Jeff Masters
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