Posts

Steven Copertino

Public Analysis: Strong to Severe Thunderstorms This Afternoon

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Severe Weather Video Update (Doug Simonian)

An active afternoon and evening is possible as a large area of low pressure moves through the Great Lakes region and into Canada today. The progression of this low pressure system to our northwest has allowed for warm/moist air to surge in from the south and provide a marginally unstable airmass for the southern half of the region as of 1pm. This unstable airmass will be aided by very strong wind shear, which is essentially the difference in wind direction as you get higher in altitude within the atmosphere. Even though most of the area did have heavier showers and even some isolated rumbles of thunder this morning, clearing has begun to take place. This is allowing for the sun to peek through some leftover high clouds and this will work to warm up the moist ground, which promotes evaporation. This evaporation ahead of the line of storms will allow for more instability to build, which will be key for the strength of any potential thunderstorms later on. As of right now it does appear that the greatest amount of clearing is currently taking place along the central and southern zones of NJ and PA, and as a result these areas are under a Severe Thunderstorm Watch mainly for damaging winds in excess of 60 mph ( Storm Prediction Center in Oklahoma)

Current visible satellite imagery showing clearing begining to take place in PA and parts of NJ (Simuawips.com)

Current visible satellite imagery showing clearing beginning to take place in PA and parts of NJ (Simuawips.com)

The area of storms expected to impact the region is currently located back in Pennsylvania with multiple severe thunderstorm warnings active. In addition, we have begun to notice some increase in intensity over the past hour as this line passes over locations that experienced areas of scattered sunshine earlier. This line will be sustained by the very strong upper level winds and an increased instability feed from the south and we expect this line to begin to impact the region around 4pm. As mentioned the exact intensity of these storms will be highly dependent on how these storms interact with the environment, but we expect the southern zones (SE PA, SNJ, and into portions of Central NJ) to receive the strongest impacts with the potential for damaging wind gusts, lightning, heavy rains, and possibly some small hail in the strongest storms. Further north, the lack of instability will limit the potential impacts to some strong winds and occasional lightning as well as some heavy rain that will reduce visibility.

Current look at the radar along with active Severe Thunderstorm Watches and Warnings across the area (Courtesy of Simuawips)

Current look at the radar along with active Severe Thunderstorm Watches and Warnings across the area (Courtesy of Simuawips)

Gradually, the threat for severe weather will shift southeast through these zones during the afternoon and early to mid evening hours. The main complex of storms will move offshore, shifting through Southeast NJ (Atlantic City and Cape May) during the early to middle evening, and then offshore. Cooler and more stable air will move into the area behind the storm complex.

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Make sure to stay updated over the next few hours with these potentially dangerous storms!

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Have a great day!

Steve Copertino

Miguel Pierre

Public Analysis: Strong to Severe T-Storm Threat Late this Afternoon

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An unseasonable warm airmass continues to be over region this afternoon. Clouds will mix with some sunshine and temperatures will be rising into middle to upper 60s and some lower 70s over many inland areas through middle of this afternoon. Closer the coast, moist south-southeast winds will keep more low clouds and temperatures cooler in the mid-upper 50s or lower 60s.

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John Homenuk

Localized severe thunderstorm event possible Sunday

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A complex weather system will shift toward the area from late Saturday into Sunday, with tropical moisture surging northward as it moves into parts of the Northeast United States. The main surface low pressure area will track into Southeast Canada, while a secondary low pressure area will dip southward into New York State and New England. This will help draw in more southerly winds with moist, unstable air making its way toward the area as Sunday goes on.

At the surface, a warm front will move northward from the Mid Atlantic states towards Central New Jersey by Sunday afternoon. As it does so initially, showers with embedded thunder will likely shift northeastward through the area. Occasionally torrential downpours are anticipated as it does so. The main story, however, will come during the afternoon as the warm front sets up shop near Central New Jersey on a west to east axis.

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Miguel Pierre

Thunderstorms this afternoon may be strong with gusty winds

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A warm front, associated with a wave of low pressure system over Northeast PA, has situated itself across the area this afternoon. Warmer temperatures exist to the south of the front, over Southern and Central New Jersey, where temperatures have already surged into the middle to upper 70’s. Farther northeast, colder marine air remains in place where temperatures are in the 50’s over New England. This warm front will serve as a focal point for the development of storms later today, as an upper level disturbance approaches the area.

Some of these thunderstorms may be strong to severe this afternoon, especially over Central and Southern New Jersey where stronger instability will develop. The Storm Prediction Center has issued a Slight Risk of severe thunderstorms for those areas. Meteorologically, this threat is supported by both kinematic and thermodynamic evolutions. Instability, on the order of 500-1000 j/kg of mixed layer cape, will support storm development once the upper level disturbance approaches. Mid level lapse rates may limit the threat of widespread severe weather (between 6.0 and 7.0 C), but steeper low level lapse rates in Central and Southern New Jersey, juxtaposed with favorable 0-6km bulk and speed shear may lead to some organized storms. The main threat with these storms, which will drop southeast through NJ and NY later today, will be damaging winds and hail. A weak tornado isn’t impossible, especially near the warm front with backing low level winds.

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