Steven Copertino

Public Analysis: Stormy Start to the Holiday Weekend, Possible Break for the Fourth of July?

/by

Good Evening! 

As was mentioned all the way back on Monday, today has featured quite an extensive development of showers and thunderstorms over much of the Northeast. These storms were fueled mainly by the built up heat and humidity which created modest levels of instability to build during the afternoon hours today. Additionally, the storms were aided by strong vertical wind shear in the atmosphere, which helped some storms to produce damaging wind gusts, and even some rotation which prompted at least three tornado warnings. Radar images also indicate that there is a rather high amount of moisture in these showers and thunderstorms, which can be attributed to the impressive resurgence of tropical moisture over the area that occurred yesterday when the high pressure that was over our area on Tuesday began to back away to our east, causing winds to surge from the south. As opposed to most days this year that featured decent convective development, these storms were generated by a strong mid level short wave at around 700mb, in contrast to the traditional cold front.

While the vast majority of any actual severe weather was confined to areas well north and west of our area, some locations in southern New York and portions of Connecticut did see some wind damage, frequent lightning, and very heavy rainfall. As the evening rolls on and the sun gradually fades away, the heat and instability that we had will begin to drop off quite significantly, and any remaining strong storms will weaken below severe limits, while heading generally eastward. Some storms in southern Connecticut may still be capable of producing damaging winds as they feed off residual instability and favorable parameter space that had not been touched by previous cells.

The rest of the evening should feature improving conditions, with partly cloudy skies likely for most of the area. Due to the lack of a coherent frontal system, the humid airmass that spawned these storms will linger around and make for another muggy night, with lows likely staying in the lower 70’s and into the middle 60’s.

Animated loop of the evenings latest regional radar mosaic, regional surface observations, and high resolution visible satellite imagery (Courtesy of College of DuPage)

Saturday should start off quite nice, with a mix of sunshine and scattered clouds to start off the day. Although, with warm mid level temperatures, winds from the south, and a humid airmass in place, the conditions will be ripe for temperatures to quickly rise into the upper 80’s and even pass the 90 degree mark in locations like NE NJ and SNY. As we go through the late morning and early afternoon hours, a shortwave trough and associated cold front will be working its way east towards the area. This will set the stage once again for instability to begin to pool up ahead of the frontal system, which will act as a forcing mechanism for thunderstorm development later into the afternoon. Like today’s threat, the best wind shear and parameters are likely to stay to the North and West of the immediate New York City area, but more isolated strong storms will be possible towards the area as the day progresses on. The main threats tomorrow appear to be gusty winds, frequent lightning, and very heavy rainfall. Due to this risk, the Storm Prediction Center in Norman, Oklahoma has placed locations to our north and west in a Slight Risk for severe thunderstorms.

Showers and storms may continue to longer through the late afternoon and evenings hours as the lift associated with the cold front will trigger additional shower and possible thunderstorm development if there is any left over instability to work with. The main threat from these storms later in the day appear to be confined to gusty winds and heavy rain. Lows tomorrow evening will remain quite warm, with upper 60’s and lower 70’s likely.

This evenings latest Rapid Precision Model, showing scattered showers and thunderstorms developing mainly to the north and west of the city tomorrow afternoon/evening (Courtesy to WSI)

This evenings latest Rapid Precision Model, showing scattered showers and thunderstorms developing mainly to the north and west of the city tomorrow afternoon/evening (Courtesy to WSI)

Sunday should feature a less humid start to the day as the cold front moves through during the early morning hours and mixes out the tropical airmass that has been lingering over the past few days. As dry air behind the front moves on in, mostly sunny conditions are likely to hold up for the rest of the day on Sunday. With mostly sunny skies and a much less humid airmass over the region, high temperatures will gradually build up towards the upper 80’s-with some locations possibly reaching that 90 degree mark once again!

Monday will likely features much of the same conditions as Sunday, with low humidity, clear skies, and an overall low threat for afternoon storms. Highs should also be quite similar, with temperatures likely peaking around the middle to upper 80’s. Overall, both days will be very pleasant and a great lead up to Independence Day.

Tuesday (Fourth of July) – the day that everyone has been wondering about for over a week now actually looks to have quite an excellent setup in place during the day! A stationary front-the remnants of the cold front that passed on Sunday-will be located to our south, which will leave a large area of high pressure in control for the day, providing light winds, low humidity, and clear skies! Highs should continue their warm, but not outrageously hot trend, with temperatures likely reaching the middle 80’s over much of the area! In summary, it should be an excellent outdoors day, with near perfect conditions for firework-viewing, with only high cirrus clouds likely during the day!

We hope everyone has an excellent Holiday Weekend!

A quick summary of the conditions for the Fourth of July-orange colors denote areas of higher than normal pressure

A quick summary of the conditions for the Fourth of July-orange colors denote areas of higher than normal pressure

For more information and posts like this one, make sure you sign up for Premium 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: Above Normal Temperatures and Thunderstorm Threats Return for the Holiday Weekend

/1 Comment/by

Good Evening! 

Today was yet another beautiful day across the Northeast due to a weak area of high pressure to our south bringing in low humidity, mild temperatures, and light southerly winds for the entire region. Highs today were generally limited to the low to upper 70’s across our area due to cooler temperatures aloft associated with a deep area of mid level toughing located just to our north. As we get deeper into the evening hours across the area, high altitude cirrus clouds should begin to move in from the west, signaling the beginning of another pattern change. With clear skies, low dewpoints, and light winds from the west, conditions will be near-perfect for radiational cooling to take place, so expect low tonight to fall into the middle 50’s to low 60’s across the area, with some locations well-removed from the coast possibly sinking into the low 50’s during the early morning hours.

This afternoon/evenings latest high-resolution visible satellite imagery, surface observations, and regional radar mosaic, showing relatively calm and mild conditions for your Wednesday evening.

Thursday is looking more like a rather large step in the direction of above-average temperatures for the entire region as mid level ridging to our south and east begins to build northward over our area, especially during the afternoon hours. The same high pressure that provided the area with extremely comfortable weather over the past few days will begin to turn on us by directing winds from the south and southeast. This will lead to much higher dewpoints overtaking the tri-state area, which will lead to a muggier feel for tomorrow. In addition to the increasing humidity, rising heights will also allow mid level temperatures to rise significantly. The combination of warm mid level temperatures, a muggier airmass, and southerly winds will lead to high temperatures likely reaching all the way into the middle to upper 80’s tomorrow with some potions of Notheastern New Jersey and southern New York state likely seeing temps pass that 90-degree mark.

In lieu of all this warmer weather, a pretty tight pressure gradient will set up shop over the area as the aforementioned high pressure system begins to move off of the Mid-Atlantic Coast and an area of low pressure in the Great Lakes Region continues to gradually move north and east. This will likely increase winds to around 15-25 miles per hour, with gusts likely reaching into the 30-40 mph range during the day. Some isolated wind gusts will be capable of taking small twigs off of trees and blowing around lawn furniture. Additionally, this strong southerly flow may be able to limit just how warm south-facing shores of Long Island and Connecticut can get tomorrow if the winds kick in during the early afternoon hours as opposed to later in the day.

Later tomorrow evening, increasing mid level moisture as well as the enhanced southerly flow should create some increased cloudiness, with any chance at some showers limited to the far northern regions due to a total lack of forcing for any kind of thunderstorm development. Tomorrow evening will be quite warmer than Wednesday evening as temperatures are only likely into the middle to upper 60’s, with some 70 degree low temperatures possible in the more insulated locations.

This evenings North American Model showing relatively high wind gusts tomorrow afternoon and into the evening hours due to an increasing pressure gradient overhead. Please refer to the NWS for any potential Wind Advisory's tomorrow

This evenings North American Model showing relatively high wind gusts tomorrow afternoon and into the evening hours due to an increasing pressure gradient overhead. Please refer to the NWS for any potential Wind Advisory’s tomorrow

Friday looks to be yet another warm and borderline hot day as mid level ridging continues to build over the area. With the high pressure firmly off of the Mid Atlantic coast by this time, winds from the south should continue to usher in very warm and moist air in the lower levels of the atmosphere that will push a frontal system well to our north. With this frontal system located to our north, any potential pieces of energy that will be capable of triggering any shower and thunderstorms will also remain north of our area during the day. Regardless, Friday will likely be another increasingly muggy and warm day with mostly sunny skies leading to highs in the upper 80’s, and possibly even 90 once again for portions of New Jersey and southern New York. Friday evening looks to be a warm, but bearable one as humidity decreases ever so slightly, but temperatures will likely remain in the low to middle 70’s for lows.

As of now, it appears that the more unstable day appears to be on Saturday as a frontal system associated with some energy from an approaching mid level trough over the Great Lakes region heads eastward. Saturday will also likely feature rich tropical moisture, increasing instability, and some improved wind fields that will be necessary for thunderstorm development towards the afternoon hours. While the thunderstorm threat will definitely need to be revisited on Friday, there does seem to be support from the NAM, GFS, and ECMWF for this scenario. Anyway, Saturday will likely feature mostly sunny condition’s, with increasing clouds towards the afternoon hours once again. Highs will likely be able to eclipse Fridays highs, with 80’s and lower 90’s looking possible.

Sunday also looks to be rather unsettled with increasing cloudiness and an enhanced threat of showers and thunderstorms as yet another lobe of energy rounds the base of the trough located in southern Canada. This lobe of energy will send off some energy through the Ohio Valley, which will act as a trigger and potential development zone for precipitation during most of the day. Due to the enhanced clouds, Sunday will likely be only slightly cooler than the previous two days, with highs likely reaching into the mid 80’s.

This afternoons European model showing yet another possible Canadian disturbance dropping southward and potentially increasing the threat for showers and thunderstorms for the later half of the holiday weekend (Courtesy of AccuweatherPro)

This afternoons European model showing yet another possible Canadian disturbance dropping southward and potentially increasing the threat for showers and thunderstorms for the later half of the holiday weekend (Courtesy of AccuweatherPro)

Drier conditions appear possible for Monday as a subtle mid level ridge builds in behind the weekend system, but this afternoons model guidance has been hinting at the potential for another system to work its way in and potentially provide another chance for some showers and thunderstorms on the 4th of July. We will have a full update on the Holiday Weekend and beyond on Friday afternoon!

For more information and posts like this one, make sure you sign up for Premium 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

Miguel Pierre

Premium Long Range: More Heat & Severe Weather Risks Going Into July

/by

After a few showers and thunderstorms this afternoon, more pleasant weather with temperatures near to slightly below normal will continue over the next few days. But there are many signs of overall pattern change support more typical mid-summery weather with some hot temperatures, humidity and some thunderstorms over the region, as we move into the few weeks of July.

A trough will dig into the Northern Rockies and Plains during the middle of this week. This will cause ridge build over Northeast and Mid-Atlantic region late this week and into this weekend. This will much warmer and humid airmass to return to region. Temperatures with more southwest flow and enough sunshine could exceed 90°F degrees in many spots by Friday and Saturday. Some afternoon sea-breezes each day will likely some coastal sections a little cooler. But it still be uncomfortably humid.

Read more

Steven Copertino

Public Analysis: Calm and Cool Conditions Gives Way to Hot and Stormy By Friday

/by

Good Evening! 

We had a rather wild Saturday morning this past weekend as the remnants of Tropical Storm Cindy stormed through the area along with a rather strong cold front. All of the deep tropical moisture and forcing from Cindy and the cold front allowed a rather impressive line of torrential rain and embedded thunderstorms to move through the area early on Saturday morning. This area of heavy rain did bring some flooding to locations as rainfall rates increased to over one inch per hour, but also brought some extensive wind damage, along with two confirmed tornadoes in Monmouth county, New Jersey! After the cold front moved through, we saw a much direr air mass take over yesterday, which has persisted through the day today, and should last another 48 hours. Afterwards, it appears that a large area of high pressure will form just off the East Coast and looks to bring above normal temperatures back to the region, with the addition of another muggy air-mass and the threat of some strong thunderstorms towards the end of the week.

———-

This Evening Into Tomorrow

As mentioned, today was a very pleasant day with mostly sunny skies, light winds, and cooler temperatures thanks to a rather moderate and dry air mass in place over the region. High temperatures were able to stick into the mid to upper 70’s, which is slightly-below, or just around seasonable for this time of year. Some locations saw temperatures drop off a bit during the afternoon hours as sea-breezes made their way inland over portions of Long Island and Connecticut. There was some threat of isolated showers and thunderstorms this afternoon, but the lack of a strong trigger and very dry mid levels of the atmosphere seem to point that nothing more than a few cumulus clouds should be expected for the remainder of the day and into the evening.

As we continue into the evening hours, a very unusually strong mid level trough for this time of year will continue to pivot eastward, and drags another cold front with it. While this afternoons models were hinting at some rain later this evening associated with this cold front, it seems that the aforementioned dry air should put a kibosh on any precipitation. As the front approached the area, falling heights out ahead of the upper level trough should allow for clouds to increase, but with light winds and a very cool vertical temperature profile in place, overnight lows should drop to below-normal levels, with low to mid 60’s likely for most of the area, and 50’s possible for areas further away from the coast.

This evenings latest regional radar mosaic, HRES visible satellite imagery, and surface observations showing relatively calm conditions, with some showers and thunderstorms to the north and west (Courtesy of College of DuPage)

This evenings latest regional radar mosaic, HRES visible satellite imagery, and surface observations showing relatively calm conditions, with some showers and thunderstorms to the north and west (Courtesy of College of DuPage)

Tuesday morning should feature mostly sunny skies to start the day as a cold front begins to move through the region. By the late morning to early afternoon hours, the anomalously strong trough centered to our north and west will continue to move east and be overtop the area, with very cool mid level temperatures. These cold mid level temperatures will become important tomorrow afternoon as the surface temperatures begin to rapidly warm up, causing a very healthy amount of rising motion in the atmosphere. Combined with very marginal instability, we could see one or two showers or even an isolated thunderstorm pop tomorrow afternoon, but due to continued dry mid levels of the atmosphere and the overall lack of a trigger, the most likely outcome is that clouds should begin to increase, with cumulus clouds becoming quite numerous by the late afternoon. With the cooler mid level temperatures in place and light southerly/southwesterly winds expected to be in place, high temperatures should be able to reach into the mid to upper 70’s, with some areas possibly even hitting the 80 degree mark with prolonged sun.

Otherwise, skies should begin to clear and winds should become calm as an area of high pressure begins to build in behind the cold front to our west. This high pressure system will usher in another cool and dry airmass for the region, which should allow quite favorable conditions for radiational cooling to take place during the evening hours tomorrow. This should allow temperatures to drop into the lower 60’s and even the 50’s once again!

This afternoons high resolution North American model showing a very pleasant day on Tuesday afternoon just before a cold front works its way on in from the west, bringing yet another mild and dry airmass (Courtesy of Tomer Burg)

This afternoons high resolution North American model showing a very pleasant day on Tuesday afternoon just before a cold front works its way on in from the west, bringing yet another mild and dry airmass (Courtesy of Tomer Burg)

Wednesday and Beyond

Wednesday will likely start off rather calm as an area of mid level ridging begins to build and move eastward during the day, with high pressure mainly in control. This should allow for mostly sunny skies and light winds from the south/southwest to take over during the day, which will likely bring temperatures in the upper 70’s to the lower 80’s for some of the more southern locations. All in all, Wednesday should be a rather beautiful day, with slightly below-normal highs and building clouds later in the day and approaching the evenings hours as a warm front begins to advance east.

By Thursday, the riding should become stationary over area and make little if any forward progress during the day, so expect winds to become a bit steadier from the southwest. Temperatures aloft will also begin to warm quite a bit, so temperatures will likely be able to climb into the low to middle 80’s during the day Thursday with mostly sunny conditions expected.

As we get towards the end of the week on Friday, its looking likely that precipitation chances will be on the increase as the area of high pressure along the east coast shifts eastward and allows rich tropical moisture to bleed northward once again. Temperatures will also be on the increase, with highs likely getting into the middle to upper 80’s, with some locations likely hitting that 90-degree mark as well. Friday appears to have more organized instability, better shear, and a more coherent trigger than any day this week, so we do feel that there is an increased risk of strong to possibly severe thunderstorms during the day on Friday, but we will have to revisit this later in the week. Otherwise, this pattern looks to continue through the weekend before another high pressure system moves through and brings a more mild airmass in time for the beginning of next week.

This afternoons European Ensembles showing an increased potential for above normal temperatures by the end of this week and into this weekend (Courtesy of TropicalTidbits)

This afternoons European Ensembles showing an increased potential for above normal temperatures by the end of this week and into this weekend (Courtesy of TropicalTidbits)

For more information and posts like this one, make sure you sign up for Premium 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