Steven Copertino

Public Analysis: Snow Squalls Possible Today, Unsettled Next Week

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As we head into the end of the workweek this afternoon and evening, most of the area is experiencing quite the contrast from what we were looking at this time last week. Some heavier snow showers and temperatures in the teens are possible this afternoon and evening, with a cold weekend likely. Continuing the theme of this winter, a return to more above-normal temperatures is possible as early as Monday.

If we take a look at the visible satellite imagery this afternoon, we can see that there are numerous clouds associated with a very large and potent upper level system that is responsible for the impressive temperature drop we have seen over the past day or so across the area. This upper level system is also responsible for producing widespread snow showers and snow squalls, courtesy of very steep lapse rates (which is the difference of temperature with height). As of 2pm, the majority of these squalls were located over Pennsylvania and even though they do not look too impressive on radar, these squalls have been responsible for numerous car accidents as they are able to reduce visibility down to near-zero in less than a minute.

Current visible satellite imagery along with radar and surface observations showing numerous heavy snow squalls over PA (Courtesy of Simuawips.com)

Current visible satellite imagery along with radar and surface observations showing numerous heavy snow squalls over PA (Courtesy of Simuawips.com)

As the afternoon continues on and the atmosphere nearly maxes out the low level lapse rates as we head toward sunset, these snow squalls should continue east and possibly affect the NYC metro area by 4-6pm and 6-8pm for Long Island and Connecticut. Though these squalls may be slightly weaker by the time they reach the area, they will still be capable of rapidly dropping visibility, rapidly dropping temperatures, making roads very slick, as well as producing some gusty winds which may knock some small branches off of trees. Please exercise extreme caution if caught in these squalls, especially as we get closer to the afternoon commute. Due to the more spread-out nature and quick movement of these squalls, any accumulations should be limited to a trace in all locations.

HRRR model showing snow showers and possible heavier snow squalls working their way into the area this afternoon and evening

Later this evening, clearing skies and a very cold airmass above our heads will easily allow temperatures to drop down into the teens for inland areas and into the 20’s for locations closer to the coast, which is a massive departure from what we have experienced over the past week with lows in the 50’s! We expect the below normal temperatures to continue into tomorrow behind the large upper level system, with highs only being able to reach into the upper 20’s and low 30’s across the area. Due to a somewhat impressive pressure gradient draped over the region, there will be the potential for some gusty winds which will make it feel quite chilly throughout the day tomorrow with windchills in the single digits and teens. The winds should begin to die down towards sunset as clear skies once again dominate the area with another cold night on tap, with lows in the teens and even single digits across the area. Sunday looks to also be slightly below average with temperatures in the 30’s as an area of high pressure begins to take control over the area, which will reduce any winds and make it a much more bearable day. Overall, it should be a much more seasonable weekend, with mostly clear and dry conditions expected both Saturday and Sunday.

NAM model showing a large area of low pressure directly over our area by Sunday afternoon, providing calm and cold conditions

NAM model showing a large area of low pressure directly over our area by Sunday afternoon, providing calm and cold conditions

As we head into  Monday, the large area of high pressure over the Northeast should begin to exit to our east and position itself off of the Mid-Atlantic coast. This will allow above normal temperatures to work their way into the region from the south as a large low pressure area looks to track into the Mid-West, which may provide a chance at some heavier precipitation by Wednesday morning and afternoon as a cold front works its way through the Northeast. Model guidance diverges significantly once we reach the end of the next week, but there does exist the potential for another return to below-normal temperatures if we are able to sustain high-latitude blocking near Greenland. This is all very uncertain right now, so make sure to stay tuned over the next few days for more updates on this evolving weather pattern!

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Have a great day!

Steve Copertino

Miguel Pierre

3/03 All Zones Update: Snow Showers Possible Later Today…Colder Saturday

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Happy Friday! More wintry weather is returning to region over the next few days. A block near Greenland and some ridging over Western Canada will support an arctic airmass associated with lobe of polar vortex, and this airmass will intrude the Northeast US this weekend. Today will be colder with partly sunny skies and high temperatures in upper 30s to lower 40s. Then temperatures turn much colder tonight and tomorrow.

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Miguel Pierre

3/02 All Zones Update: More Winter-Like Weather Closes out the Week

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Happy Thursday to you all! More sunshine is expected throughout the area today, behind a cold front which moved through last night. Temperatures this morning are slowly falling out of the 50’s.  A tight pressure gradient will allow for very windy conditions to continue, with frequent wind gusts between 40 to 50mph likely and a few higher gusts up to 60mph possible. The National Weather Service has issued High Wind Warnings in most of our area for these winds, which may cause some trees, power lines and other unsecured structures to come down.

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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.

impactmap_mar1

 

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

For more information and posts like this one, make sure you sign up for Zone Forecasts — where multiple detailed articles, videos, and interactives are posted each day.

 

Have a great day!

Steve Copertino