Posts

Steven Copertino

Public Analysis: Cool and Damp Friday, Coastal Cut-Off Next Week?

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Good afternoon and Happy Friday!

Today has been another unsettled and damp day as rather thick cloud cover and some associated showers have worked their way through the region late last night and into the morning. This was due largely in part from a retreating back door cold front, or a cold front that sinks from northeast to southeast due to more dense air being able to overcome the more shallow and weak warm layer to the south. Offshore winds and thick cloud cover should remain over the remainder of the afternoon, and there does exist the potential for some patchy areas of drizzle or even a shower or two. Any steadier showers will likely be limited to areas along the coasts of New Jersey and Long Island, as the marine influence will be greatest along those areas.

With this aforementioned cloud cover and the back door cold front established well to our south and west, temperatures in North and Central New Jersey, as well as points to the north will struggle to reach out of the mid 50’s this afternoon. Further south into southern portions of New Jersey as well as southeast Pennsylvania, we may see temperatures reach into the low to middle 60’s, but this is highly dependent on whether or not if the warm sector in central Pennsylvania is able to advance during the late afternoon hours.

Some more steady showers and possibly even a thunderstorm or two may be possible for portions of southeast Pennsylvania as well as southern New Jersey later into this evening, but as of right now, it is looking like any shower /thunderstorm development will be isolated in nature. Weak instability, moderate wind shear, and some clearing skies over central Pennsylvania has lead to an area where we may see these potential showers and storms develop and potentially progress east during the afternoon hours. This area will be monitored for any potential development, so make sure to check in here for the latest and on our twitter page @nymetrowx for up to the minute updates! Due to the risk of some weak/isolated severe thunderstorms, the Storm Prediction Center in Norman Oklahoma has place portions of our area in a Marginal Risk for large hail and potentially damaging wind gusts. Heavy rain and cloud to ground lightning will also be possible with any stronger storms, so make sure to be aware of any approaching storms later on.

Latest surface temperatures, regional radar mosaic, and visible satellite imagery across the Northeast showing the very stark temperature gradient in place this afternoon (Courtesy of GREarth)

Latest surface temperatures, regional radar mosaic, and visible satellite imagery across the Northeast showing the very stark temperature gradient in place this afternoon (Courtesy of GREarth)

As we move on through the day and into the evening, a cold front will begin to push through the region later this evening. However, there is a chance that some moisture will be trapped in the lower levels of the atmosphere later on tonight, which could cause some low clouds and areas of patchy fog to remain late tonight and early tomorrow morning, especially closer to coast. Cloud cover will significantly dampen any chance of radiational cooling tonight, which should  keep temperatures from dropping out of upper 40s to lower 50s overnight over much of the region. Some interior valleys could be a little cooler in the lower to middle 40s, which is a good 8-14 degrees below normal for this time of year.

Saturday Into Sunday 

As the cold front continues to push through the southern Mid Atlantic region tomorrow morning, broken clouds and even some overcast will be possible as some residual moisture continues to stick around in the lowest levels of the atmosphere. The short-term models disagree on whether or not the cloudiness will burn off or not through the afternoon hours, but we do expect some peeks of sunshine tomorrow with a relatively cool air mass settling in tomorrow. With some limited cloud cover, light winds, and cooler mid level temperatures expected tomorrow, temperatures should be able to only rise into the low to middle 50’s across most of the New York metro area, with the possibility of interior locations possible seeing highs limited to the upper 50’s due to cool northwesterly winds from Canada. These winds will also usher in some more dry air into the mix, so expect any residual clouds to gradually fade iater into the day.

Sunday will be the beginning of another unstable period as a low pressure system in the mid levels of the atmosphere “cuts off” from the main flow and begins to meander towards the southeast coast of the United States. This low pressure will have a very nice feed of moisture from the Gulf of Mexico, so it’s overall precipitation field should be quite large in nature, as well as have the potential to drop a moderate to heavy amount of rain wherever it does track. This afternoons guidance really has not converged on any particular solutions, with some models bringing the low from the Outer Banks of North Carolina, to just offshore of the southern coast of Long Island, while other models have the system meandering off the Mid Atlantic coast with little, if any direct impacts through Sunday and Monday.

As of right now, we expect that this system will not be able to gain enough latitude once it reaches the southeast coast to impact our area with any significant rains or winds at this time. High pressure centered in Canada will likely keep this system offshore throughout this period, but this system will need to be monitored, as a small deviation in overall setup could chance the forecast quite a bit.

12z GFS model showing the large cutoff low pressure system stalling out and remaining off of the Mid-Atlantic coast throughout the weekend and into early next week.

Extended Range  

Stronger ridging should begin to develop over our area on Monday and into Tuesday, and this will begin to force the remnants of the cutoff low to the south and east early next week. This should allow any significant impacts like heavy rain and winds to remain well-offshore before the system gradually weakens and heads out to sea. More unsettled weather will likely take shape once again as a very active Pacific jet stream begins to set up off of the west coast of the United States.

This very active jet stream will have the potential to place a deep trough in the central portions of the country, which would in turn bring a large ridge of high pressure into the southeastern region of the country. This combination would be capable of bringing temperatures well-above normal next week for the Northeast, along with the risk for multiple rounds of severe storms in the Plains states and on east, possibly beginning on Wednesday. Regardless of the exact details, it does look like we are possibly heading into a very active and warm pattern once again, so make sure to stay tuned over the next few days for more updates!

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Have a great weekend!

Steve Copertino

Steven Copertino

Public Analysis: Much Cooler Today, Multiple Rain Threats Ahead

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Good Afternoon!

High pressure off of the Canadian maritimes has set up in the perfect position today to usher in cool winds from the Atlantic, keeping temperatures a good 10-12 degrees below what they were just 24 hours ago. In addition to the cooler winds from the southeast, clouds and even some light showers have been noted across the western portions of the area this afternoon. Back to the east, there have been some breaks in the clouds noted on visible satellite imagery over parts of New Jersey and New York. Even with these breaks in the cloud deck temperatures have not been able to get much higher than the low to mid 50’s, with temperatures in the 40’s being reported over portions of Long Island and Connecticut.

Cloudy skies and cooler temperatures should continue to be the theme for the rest of today as a mid-level warm front begins to approach from the west later this afternoon and into the evening hours. This front will bring increasingly cloudy skies and even the threat of some showers later this evening as available moisture begins to increase in conjunction with the passing of this front.

As the evening progresses onwards, a very weak cold front associated with a disturbance in Canada will pass through the region and bring yet another chance at some more showers as lift with this system is only slightly stronger than the warm front that preceded it. Overall, it should be a rather raw and dreary afternoon and evening as temperatures remain pretty much capped off in the 40’s to low 50’s across the entire area.

Latest visible satellite imagery, surface temperatures, and regional radar mosaic showing a relatively cool Spring day (Courtesy of GREarth)

Latest visible satellite imagery, surface temperatures, and regional radar mosaic showing a relatively cool Spring day (Courtesy of GREarth)

Thursday into Friday Afternoon 

Tomorrow morning should start off with some broken clouds across the metro area as weak upper level energy riding up and over an area of high pressure. At this time it seems that any shower  activity  should remain quite limited, though some areas of drizzle may be possible along the coast early on in the morning. As tomorrow continues on, a surface warm front looks to move north through the region and provide a renewed chance at some more low to mid-level cloudiness as more warm/moist air begins to work its way in.

There are still some questions as to how much warming occurs tomorrow with the combination of some leftover southeasterly winds off of the Atlantic, as well as increasing cloudiness, but it does look like tomorrow will at least be a warmer day than today. Temperature should be able to rise into the mid to upper 60’s for locations away from the coast, but highs may struggle to get out of the 50’s for coastal sections of New Jersey, Long Island, and Connecticut. Some inland locations of New Jersey and Pennsylvania may have a chance at reaching the low 70’s, but this will be highly dependant on the aforementioned variables.

The area of low pressure that we mentioned back in Friday’s discussion will begin to track through the upper Great Lakes region late Thursday afternoon and evening, and this will bring yet another warm front for our area later in the evening. However, confidence decreases significantly as a high pressure system coming down from central Canada and stalling over portions of southeast Canada may work to stall this warm fronts progress. Where this warm front stalls will dictate where cooler temperatures setup Thursday night. Areas north of the front will see lows back into the 40’s and low 50’s. Areas to the south will see temperatures remain in the 50’s to possibly even low 60’s overnight as southerly flow increases.

Unlike the warm front passing through this evening, the front tomorrow night and into Friday morning should have enough moisture and dynamics associated with the area of low pressure passing to our north to provide a decent chance at some showers and even thunderstorms. With limited instability, a strong low level flow, and deep moisture transport, it appears that there will be a chance at some convection possibly developing during the evening hours. The main threat with these storms appears to be locally heavy rainfall and possibly some flooding for areas with poor drainage, so make sure to stay up to date on these possible storms over the next 24 hours.

15z Rapid Precesion Model showing some heavy showers and thunderstorms developing from west to east on Thursday evening and into Friday (Courtesy of WSI)

15z Rapid Precession Model showing some heavy showers and thunderstorms developing from west to east on Thursday evening and into Friday (Courtesy of WSI)

Friday Evening and Beyond

Finally, a cold front, will come through later Friday afternoon and evening. But any more showers will be more widely scattered with less lift and instability along and ahead of this front. Skies will finally clear later Friday night and Saturday, as weak high pressure build into the Northeast, behind this storm system. Sunshine with northwest downslope winds on will help temperatures rise into back into the lower to middle 60s on Saturday afternoon.

As we continue onwards, the active pattern looks to continue as the computer models are keying in on the potential for a storm system to approach from the southwest on Saturday evening, however they diverge significantly on the strength and timing of this system. As of this afternoon it appears that at least moderate rain appears likely as this system tracks to our south, and then stalls off the Mid Atlantic coast on Sunday.

It is worth noting that this system will be moving across the southern Plains and will have time to take in a considerable amount of water vapor before it reaches our area and it is also important to mention that with a considerable amount of time left in this forecast, there is the potential that this system could trend stronger when it passes to our south as well as potentially stall closer to the coast than what some of the models currently have. This would possibly bring a more significant system for our area on Sunday and possibly into Monday, with heavy rain and even some strong winds possible for the coast.

12z European model showing an area of low pressure over the Southeast US states potentially bringing the threat of moderate rains later this weekend (Courtesy of Accuweather Pro)

12z European model showing an area of low pressure over the Southeast US states potentially bringing the threat of moderate rains later this weekend (Courtesy of Accuweather Pro)

Make sure to stay tuned over the next few days for updates on the potential storms tomorrow evening, and our next storm chance this 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

Steven Copertino

Public Analysis: Cooler and More Unsettled Pattern Taking Shape

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Good Afternoon!

The work week has had a rather dreary start today as cloudy skies and even some rain showers pushed through the area this morning and afternoon. Most of these showers were relatively light in nature, but most of the metro area remained at least under rather thick low level clouds. This area of cloudiness and showers was caused by a weak disturbance in the mid levels of the atmosphere just ahead of a larger system that is still located back in southern Canada.

As of 3pm this afternoon, the clouds and showers associated with this weak system have begun to dissipate and move to the east/southeast, giving way to clearing skies over northeast NJ and portions of Connecticut. Despite the cloudy conditions and the mixed in showers, temperatures have been able to rise into the mid to upper 60’s this afternoon. In fact. the locations that are beginning to see more sun poke through the clouds this afternoon have actually made it back into the low to mid 70’s. Even though these temperatures are still slightly above normal for this time of year, they are still a good 15-20 degrees cooler than the highs this time yesterday afternoon. Temperatures may continue to warm for portions of central and southern New Jersey as gradual clearing takes over, but overall highs should remain in the mid to upper 60’s with some locations able to break into the low 70’s.

As we work our way into later this afternoon and evening, more gradual clearing will begin to overspread the entire area behind the weak disturbance and antecedent cold front.  Some breezy winds of around 25-30 mph may linger into the evening hours, but as we progress towards sunset, winds should begin to subside, eventually giving way to clearer and more calm conditions. These conditions should allow for all locations to see some rather cool conditions once again this evening, as lows drop into the 40’s for coastal locations and possibly down into the upper 30’s for farther inland locations.

Latest surface temperatures, regional radar imagery, and visible satellite imagery showing improving conditions across much of the area this afternoon (Courtesy of GREarth)

Latest surface temperatures, regional radar imagery, and visible satellite imagery showing improving conditions across much of the area this afternoon (Courtesy of GREarth)

Tuesday Into Wednesday

As we move into tomorrow, generally cooler weather is expected once again as offshore flow brings in a cool maritime air mass from the Atlantic. Winds out of the northwest will also usher in drier conditions as well, so expect mainly clear skies during the day tomorrow with rather pleasant conditions. High pressure located to the northeast will also help to keep things relatively calm and seasonable for this time of year as highs stay in the mid to upper 50’s across much of the area, with a few locations seeing temperatures creep into the lower 60’s tomorrow afternoon.  Tomorrow should feel quite pleasant with frequent sun and light winds, but tomorrow should be right around normal for this time of year. 

Tuesday evening should see a gradual increase in clouds as moisture from the offshore winds bring in some low level moisture. Depending on how much cloudiness winds up manifesting tomorrow night will ultimately determine just how cool the low temperatures can get, but right now it seems that most of, if not all of the area will be seeing lows tomorrow evening in the 40’s. There is a small chance that inland locations that are further away from the coast, and therefore have less chance of marine influence, could possible see lows dip in the upper 30’s, but this will have to be monitored.

As we talked about last week, we are headed into what looks to be a more active pattern later this week that is quite reminiscent of late March as multiple storm systems and potential backdoor cold fronts have the possibility to impact our area. As of right now, Wednesday looks to be a rather seasonable day with broken clouds likely throughout the day just ahead of a gathering storm system in the central part of the county. This storm system will continue to head east towards the area throughout the day, and at least bring some enhanced cloudiness towards the evening hours. 

12z GFS 13km model showing a gathering storm system on Wednesday over the central US on Wednesday evening (Image courtesy of GREarth)

12z GFS 13km model showing a gathering storm system on Wednesday over the central US on Wednesday evening (Image courtesy of GREarth)

Thursday and Beyond 

Thursday should be a rather unsettled day as a frontal boundary ahead of the main area of low pressure in the Ohio Valley begins to sink to the south of the region. This should provide a chance at some showers and possibly a thunderstorm or two before the main low pressure approaches on Thursday evening. As of right now, there seems to be two main options for the late week storm, with the first option looking somewhat more likely as of this afternoon’s model guidance.

This option would mean that the main area of low pressure in the Ohio Valley would be able to lift the frontal boundary that was previously to our south, back up to our north. This would bring more warm/moist air into the area Thursday evening and into Friday afternoon. In this scenario, the low pressure would then track along the frontal boundary to our north during the day on Friday, and this would in turn bring the potential for heavier rain, with some thunderstorms also possible if enough instability is able to work its way in.

The other scenario would be that the low pressure system and frontal boundary remains to the south of the region late Thursday and into Friday, thus a cooler and steadier rain would be more likely. While both scenarios have the potential for heavy rain, the first option would be more intense, but also more localized. The second option would obviously be much more widespread and could even have a wind threat associated with it if the system remains far enough to the south.

12z European model showing the main area of low pressure tracking well to our north on Friday morning, bringing in a more moist/unstable airmass with the potential for heavy showers and even thunderstorms (Valid 2am Friday)

12z European model showing the main area of low pressure tracking well to our north on Friday morning, bringing in a more moist/unstable airmass with the potential for heavy showers and even thunderstorms (Valid 2am Friday)

As we head into the weekend, there is a chance things may briefly calm down, but overall temperatures are likely to remain slightly above or near normal through the weekend. Afterwards, there is a chance that a more substantial rain event could take place. This afternoons guidance has been hinting at the potential for a coastal system to impact the region, but this is of course in the long range and there is a great amount of uncertainty right now.

Regardless, it seems that things are going to become active once again with multiple rain chances over the next 7-10 days, so make sure to stay tuned for future updates on the upcoming pattern!

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 afternoon!

Steve Copertino

Miguel Pierre

3/27 All Zones Early Afternoon Update: Dreary and Unsettled Weather Continues

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Happy Monday afternoon! Showers this morning were mainly associated with a shortwave trough. Which is now moving northeast of the region this afternoon. As the warm front slowly lifts northward through the region, skies may begin to brighten or break for sunshine across parts of the area later this afternoon. But it will remain dreary with mostly cloudy skies overall, through early this evening. A few more scattered showers are possible as well. Some areas of patchy fog and drizzle may continue be around this afternoon, especially near the coast. But visibilities should gradually improve.

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