Steven Copertino

Public Analysis: Calm and Cool Weekend, Turning Unsettled Next Week

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Good afternoon and Happy Friday! 

Today has been yest another hot and relatively muggy day in a strong of abnormally warm, summer-like heat. This heats time is very limited as a cold front is set to move through the region, leaving much cooler and stable conditions for the upcoming weekend. As discussed over the past week or so, high-latitude blocking over Greenland and Atlantic Canada will set the stage for a large upper level trough to set up over the eastern two-thirds of the country. This trough will likely bring a few shots at some heavy precipitation, potentially lasting through much of the work week as we draw closer to the Holiday Weekend!

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Today and This Evening

This afternoon we saw temperatures shoot back up into the upper 80’s and lows 90’s across the entire region, with some stations like La Guardia Airport and Caldwell, New Jersey seeing highs shoot into the mid 90’s (95F)! Despite the clear skies and slight breeze today has also felt relatively muggy as dew-points rose into the lower to mid 60’s. This muggy air-mass has also allowed instability to build over much of the Mid-Atlantic and Northeast states, and combined with some modest wind-shear, has allowed some very isolated showers and thunderstorms to develop across portions of New Jersey and Southeastern Pennsylvania. Due to the fact that the best instability and wind-shear are disjointed from each other, the prospects of widespread, organized thunderstorms is quite low. However, very isolated showers and thunderstorms will be possible, especially over southern New Jersey and Southeastern Pennsylvania. The main threat from these showers and storms will be gusty winds of around 40-50 mph, however small hail and frequent lightning may be possible with some of the stronger storms.

As we head into this evening, a cold front located over southern New England and central New York state will continue to sag south and overspread the region late tonight and into very early tomorrow morning. The flow behind the front will begin to change from very warm southerly winds, to much cooler northerly winds from Canada. These will bring lows down into the 50’s for much of the area, which will be quite the departure from what we have seen over the past few days.

Latest visible satellite imagery, station observations, and regional radar mosaic over the area, showing yet another warm and muggy afternoon. (Courtesy of College of Dupage)

Latest visible satellite imagery, station observations, and regional radar mosaic over the area, showing yet another warm and muggy afternoon. (Courtesy of College of DuPage)

This Weekend

As we start up the weekend tomorrow morning, we should see some relatively cloudy skies behind the cold front as an area of mid-level moisture works in over cool easterly winds coming off of the Atlantic which should produce areas of overcast and scattered clouds throughout most of the day. Temperatures should be relatively cool with highs in the upper 60’s to lower 70’s, which will be 20-25 degrees cooler than the past three days for much of the area. In addition to these cooler conditions, the Canadian/Maritime airmass will limit any chance for measurable precipitation throughout the day. As we head into tomorrow evening, an area of high pressure will be moving to our north and will work to reinforce the maritime airmass over our area. This will allow temperatures to drop into the upper 40’s and lower 50’s across much of the area, with partly cloudy conditions remaining.

We should see more clouds on Sunday as the continued maritime airmass and weak mid-level moisture hold over the area. Temperatures should be in the upper 60 to lower 70 range once again, but these highs should be quite variable as any areas that see prolonged peaks of sun may raise above the lower 70’s, while areas closer to the coast that may see prolonged cloudiness and southeasterly winds could wind up staying in the middle 60’s. Moisture will begin to increase later Sunday as the area of high pressure begins to shift off of the New England coast and as an area of low pressure moves through the Great Lakes region. This area of low pressure will drive a warm front through the Mid-Atlantic region, just south of our area. As time progresses, cloudiness will be on the rise and will likely become overcast towards the end of the evening as winds shift from easterly, to southerly once again. This afternoons model guidance was not in agreement on the exact timing, but the aforementioned cold front will likely not be able to progress east enough to produce widespread showers by Sunday evening. Overnight lows should remain quite moderate, with temperatures likely staying in the low 60’s to upper 50’s for most of the area.

This afternoons European model showing moisture beginning to build to the south of the region as a cold front associated with an area of low pressure in the Great Lakes begins to trudge eastward (Courtesy of AccuweatherPro)

This afternoons European model showing moisture beginning to build to the south of the region as a cold front associated with an area of low pressure in the Great Lakes begins to trudge eastward (Courtesy of AccuweatherPro)

Next Week

This afternoons model guidance did differ on the exact timing and placement of the cold front by Monday morning, but indications are that it should be located over eastern Pennsylvania by the morning commute. With moisture surging up to the east of the front, substantial cloudiness is likely to be present over the region, but depending on just where the warm front is located, some isolated peaks of sun will be possible. High temperatures on Monday will be very dependent on where the warm front is located as this will dictate where partial sunshine will be possible. By late morning, the actual cold front will likely move through the region and will likely have the potential to bring some showers and thunderstorms over the region. A strong southerly jet will continue to feed moisture north over the area for six hours or so and there will be the potential for some heavy rainfall with training storms. Although it doesn’t seem overwhelmingly likely, there may be the potential for some localized flooding, so make sure to stay tuned for further updates!

Tuesday will likely be a calm and cooler day as another storm begins to gather to our south with more possible moderate to heavy rainfall for the area on Wednesday. This will continue to be the theme for the week as a large upper level trough will be cemented over the central and eastern states due to another period of prolonged high latitude blocking that will allow multiple systems to slow down and congeal together to our south. While it is possible that this trough produces multiple rain threats over the next week, there is also the potential that we return to another period of below-normal temperatures coming down from Canada. Though it’s around ten days out as of today, there are some indications that this period of cooler and unsettled weather may last into the Memorial Day weekend. Stay tuned for the numerous upcoming rain threat as well as details on the upcoming Holiday Weekend!

This afternoons European model showing a very large and very anomalous upper level trough parked over the Ohio Valley and Eastern US that has the potential to bring multiple shots at heavy rain and below-normal temperatures (Courtesy of Accuweather Pro)

This afternoons European model showing a very large and very anomalous upper level trough parked over the Ohio Valley and Eastern US that has the potential to bring multiple shots at heavy rain and below-normal temperatures (Courtesy of Accuweather Pro)

or 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. Also, come interact with our staff and many other weather enthusiasts at 33andrain.com!

Have a great weekend!

Steve Copertino

Miguel Pierre

5.19 Midday Zones Update: Pleasant, Cooler Weekend…Heavy Rain Possible Monday

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Happy Friday! More hot weather continues today. A cold front will cause winds to turn more west-northwesterly and humidity to decrease this afternoon. But more west-northwest downsloping winds will support high temperatures in the upper 80s to lower 90s, over much of the region, again this afternoon. Even near the coast temperatures will be very warm, as sea-breezes will be held back by west-northwest winds this afternoon.

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Miguel Pierre

5.18 Late-AM Zones Update: More Heat and Isolated T-Storms Possible into Friday

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Good morning! More summer-like weather continues today. It will be hotter in many areas, than on Wednesday. 850mb temperatures around 17░C to 19C with southwest winds will support highs in the lower and middle 90s, away from the coast today. More record highs will likely be set again across the region.  Humidity will be higher, but not oppressive. Sea-breezes will keep coastal areas, such as Long Island and NJ shore cooler again today. But even these areas temperatures may reach the 80s, with a stronger southwest flow today.

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Steven Copertino

Public Analysis: Brief Taste of Summer, Cooler Conditions Likely This Weekend

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Good Afternoon! 

Earlier this week we mentioned that there was a strong likelihood that much of the area would be seeing temperatures rising into the mid to upper 80’s, and possibly 90’s starting today. This has indeed turned out to be true, with many stations this afternoon reporting highs in the lower 90’s across Pennsylvania, New Jersey, New York, and Connecticut. Tomorrow looks to be even warmer, with highs possibly reaching the mid 90’s by lunchtime tomorrow. However, this heat looks to be short-lived as another cool shot from Canada will likely bring temperatures back down to seasonable levels by this weekend!

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Due to the rather clear and calm conditions over the area last evening, most locations were able to drop down into the lower 50’s and upper 40’s during the early morning hours today, which made for a cool start to the day for anyone who was active before today’s sunrise. After sunrise, the clear and calm condition’s allowed temperatures to shoot up into the upper 80’s and lower 90’s across the entire region, with locations in Long Islands and coastal Connecticut seeing lower temps due to southerly winds coming off the of the cooler Atlantic ocean. This was quite the impressive rebound, and the 40+ degree rise in temperatures this afternoon actually helped a few record highs get surpassed, with LaGuardia Airport(NY), Monticello (NY), Danbury (CT), Hartford (CT), and Belmar (NJ) all beating their daily high temperatures. The rest of the afternoon should continue to be quite warm and pleasant, with the sea-breeze likely working its way deeper into portions of New Jersey, Southeastern New York, and Connecticut.

Later this evening, temperatures should stay relatively mild as the humidity begins to increase as a subtropical high pressure system off of the southeast coast continues to move eastward and pump up moisture from the Gulf and Atlantic. Clouds may begin to increase during the evening, as increasing high-level clouds were noted on the latest visible satellite imagery. Overnight lows should remain in the upper 50’s to upper 60’s across much of the area, with the exceptions of coastal communities, which may see lows in the middle 50’s due to continued southerly winds blowing in from the cooler Atlantic.

Latest visible satellite, surface temperatures, offshore buoy data, and regional radar mosaic showing very warm temperatures over the area this afternoon. Also note the cooler temperatures over Long Island and Connecticut due to the southerly winds from the Atlantic

Latest visible satellite, surface temperatures, offshore buoy data, and regional radar mosaic showing very warm temperatures over the area this afternoon. Also note the cooler temperatures over Long Island and Connecticut due to the southerly winds from the Atlantic

If today wasn’t a good enough taste of summer for you, then tomorrow will likely deliver what you desire. While we may see some overcast and broken clouds over coastal areas tomorrow morning due to the southerly winds and enhanced moisture in the lower-levels, these clouds will likely break up quite quickly during the early afternoon hours. With low-level temperatures already quite warm, clear skies, and great southerly flow, tomorrow looks to be on track to hit the upper 80’s to low 90’s across much of the area tomorrow. Some portions of Northeastern New Jersey and Connecticut may even see highs in the mid 90’s, while coastal areas of NJ, NY, and CT see cooler temperatures overall, especially once the sea-breezes begin to set in. With temps in the lower to mid 90’s, tomorrow has a high chance of breaking quite a few daily high temperature records, even more so than today did. These warm and humid conditions will likely remain well into Thursday evening, as the model guidance over the past few days has really delayed the timing of the next cold front. Expect lows to range from the upper 60’s to lower 70’s across much of the area (excluding coastal locations)

With the increasingly humid and hot conditions expected to persist into tomorrow afternoon, the National Weather Service has issued an Air Quality Alert for the entire region. Sensitive individuals including the very young, the elderly, and persons with respiratory diseases such as asthma, should avoid strenuous outdoor activities during the afternoon and early evening hours.

High resolution North American Model showing highs in the upper 80's to mid 90's tomorrow afternoon (Courtesy of Tomer Burg)

High resolution North American Model showing highs in the upper 80’s to mid 90’s tomorrow afternoon (Courtesy of Tomer Burg)

Friday Into This Weekend 

Friday will likely be warm, but not quite as warm as Wednesday (today) or Thursday were. Winds should begin to shift to more of a westerly direction during the day on Friday ahead of an approaching cold front located in Northern New York. However, it is likely that this cold front may take its time reaching the area, and with clear skies and southwesterly/westerly winds temperatures should easily reach into the mid 80’s across most of the region. Even though temperatures will remain rather warm, we should begin to see the humidity really drop off as the front ushers in drier Canadian air. Temperatures will gradually begin to fall off as the front should move through the area by late Friday afternoon or early evening. As this front drops southward through the area, temperature will drop into the more seasonable levels, with a more pronounced northwesterly wind developing.

It is worth noting that there is a potential that they delayed timing of the frontal system on Friday may allow instability to build up enough to the point that we may see isolated showers and thunderstorms develop. However, due to the dynamics that would allow the shower and thunderstorms to grow and become more widespread remaining concentrated to the northwest, it seems unlikely that any organized activity will be likely during the day on Friday.

High pressure coming from Canada will begin to move in during the evening hours on Friday, bringing a rather substantial change in air-masses. As the high pressure moves to our north on Saturday afternoon, cooler and drier conditions are likely to persist throughout the day as a more moderate maritime air-mass replaces the warm tropical air-mass that has been over our area. Highs will likely remain in the upper 60’s to lower 70’s across the entire are, with the exception of coastal locations on both Saturday and Sunday. Lows for both days will likely be quite cooler, reaching down into the mid to low 50’s once again. These temperatures will be quite a change, with highs being 12-15 degrees below-normal. Overall, it looks like a much more pleasant and seasonable weekend is on tap, so make sure to enjoy it!

This afternoons European model showing the potential for a pretty large-scale pattern change, with a deep trough located in the east for the middle half of next week and beyond

This afternoons European model showing the potential for a pretty large-scale pattern change, with a deep trough located in the east for the middle half of next week and beyond

The next rain threat looks to be on Monday as some showers and potentially a thunderstorm or two will be possible as another cold front associated with an area of low pressure will be moving through the Northeast.

This afternoons model guidance suggests that the negative NAO will once again flex its muscles, allowing for a large trough to dig into the central portion of the country and gradually progress eastward next week. This will help to once again create a stronger chance at below-normal temperatures and even the threat for a significant precipitation in the long-range as blocking continues to take shape over Atlantic Canada.

Some pleasant, warmer or drier weather could still return at times, as synoptic features in pattern still shuffle around somewhat. But no prolonged heat is expected.  Make sure to stay tuned as we get closer to Memorial Day and begin to get a grasp of what may be on the table for the holiday weekend!

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. Also, come interact with our staff and many other weather enthusiasts at 33andrain.com!

Have a great evening!

Steve Copertino