Unsettled conditions exit Friday, calm and cool weekend ahead
Good evening!
The beautiful spring-like conditions of the past two days have quickly come to an end, and have instead been replaced with a cool and rather unsettled pattern.
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Light snow likely Tuesday, frigid conditions arrive Thursday
Good evening!
Today has been a rather calm and seasonably cold day across much of the Northeast as a weak area of high pressure located to our north remains in control of our sensible weather. Spotty upper level clouds associated with a quick-moving shortwave trough moved through the southern portions of the area earlier this morning and into the afternoon hours, but quickly gave way to mostly sunny skies. Mostly clear skies and residual northwesterly flow aloft allowed highs this afternoon to stay in the upper 20’s to lower 30’s-with the vast majority of the region staying below freezing. High pressure to our north is expected to quickly move to the east through this evening and into the overnight hours. Surface flow will gradually begin to shift from the north/west, to a more southerly/southeasterly component during the overnight hours, which will help to increase cloudiness over the area. Overnight temperatures will likely be able to fall a few degrees, with readings likely staying in the lower to middle 20’s for the majority of the immediate NYC area.
~Updated Weekly Planner~
Light Snow Likely North and West of NYC Tuesday
Our attention shifts to the Great Lakes region by tomorrow morning as an area of mixed precipitation along a cold front will be moving quickly to the east towards our area. The overall setup has become much less impressive since our last update, with only light snow accumulations expected well to the north and west of the immediate NYC area. Surface winds tomorrow morning will be out of the south and east, which will help to warm temperatures into the lower to middle 30’s all the way into NE NJ and SE CT. While precipitation may start off as a mix of light rain and snow for most of the area, a quick transition to a cold rain is expected for all locations outside of elevated portions of Northern New Jersey and the Lower Hudson Valley.
Precipitation will remain predominately light to occasionally moderate in nature into the evening hours before the front begins to move across the area. We may see an increase in precipitation rates as warmer air coming in from the coast interacts with the cold/dense incoming Arctic airmass off to our west. This could create a narrow band moderate snow that moves from west to east over the area, possibly producing a quick coating to an inch all the way down to the coast as temperatures quickly fall below freezing. Precipitation will quickly end from west to east during the very early morning hours of Wednesday with the main impacts from this system primarily being felt well off to the north and west of the NYC area.
Conditions behind the cold front will be quite blustery on Tuesday night, with wind gusts potentially getting into the 30-40 mph range as temperatures drop into the lower 20’s and upper teens. The rapidly falling temperatures and gusty winds will create the potential for any residual standing water to quickly freeze on untreated surfaces-possibly creating some hazardous travel conditions.
Our latest impact map for the light mix event tomorrow. The main impacts from this system will primarily be felt well off to the north and west of the city
Frigid Arctic Air Arrives Thursday
The long-awaited “polar vortex” will be located just to the north of the Great Lakes by Wednesday morning, with very deep westerly flow overspreading the Northeast. The cold front associated with the weak surface low to our north will be exiting off the coast Wednesday morning just in time for the AM commute, allowing for gradually clearing skies. While the airmass behind this first front will be quite cold, the main Arctic front will wait until the afternoon hours of Wednesday to work its way into the NYC area. Southerly flow at the surface will overspread the NYC area ahead of the main Arctic cold front, allowing for temperatures to rise into the lower to middle 20’s Wednesday afternoon.
The aforementioned deep westerly flow directly associated with the strong tropospheric vortex to our west will cause mid level temperatures to plummet over the Northeast before surface temperatures have a chance to respond. This will create impressive “lapse rates” (change in temperature with height) Wednesday afternoon over the majority of our area. Furthermore, some weak mid level energy will be edging into portions of the Mid-Atlantic and Northeast during Wednesday afternoon. This setup will create the potential for some snow squalls to develop and quickly move from west to east around 12pm -4pm on Wednesday. Some of these squalls could be quite heavy in nature, producing very low visibilities at times and potentially dropping a quick coating to an inch for some locations. The Arctic front will finally blast through the NYC area during the late afternoon and early evening hours of Wednesday. Winds will quickly increase to around 20-30 mph, with gusts up to 40 mph as overnight low temperatures rapidly fall into the single digits across the entire forecast area–with temperatures likely falling below zero for elevated locations off to the north and west.
Thursday will be one of the coldest days of this winter season as highs struggle to make it out of the lower to middle teens for virtually the entire Northeast. Highs will be anywhere from 20-35 degrees below normal across the Northeast Thursday afternoon-which may wind up breaking a few records across the region. Wind chills will also be extremely cold, with readings likely anywhere from 10-20 degrees below zero by Thursday morning. Frigid and calm conditions will continue into the evening/overnight hours of Thursday, with lows in the single digits over the entire area.
Temperatures will moderate a bit on Friday, with highs likely getting back into the lower to middle 20’s, before a more significant warm up takes place later on this weekend.
ECMWF model showing surface temperatures anywhere from 24-36 degrees below normal on Thursday morning (AccuWx)
We’ll have an update on this Arctic airmass as well as a look at this weekend’s weather on Wednesday!
Have a great night!
-Steve Copertino
Potential midweek storm & major Arctic outbreak expected
Calm Conditions Persist Through the Weekend
High pressure will continue to build to the east during the early morning hours of Saturday, causing any remaining gusty/breezy conditions to subside significantly. Partly cloudy skies and cooler temperatures are expected to prevail into the afternoon hours, with highs likely getting back into the lower to middle 30’s for the entire forecast area. By Saturday evening, a large upper level low situated over portions of southern Canada is expected to begin to move to the south. This will set up a more southwesterly flow over the area into the overnight hours. While the mid level airmass source region will be different than this evening’s, clearing skies and relatively dry conditions throughout much of the lower to middle levels of the atmosphere should allow for robust radiational cooling to take place. This will still cause lows to drop into the upper teens to lower 20’s Saturday night-which will once again be below normal across the area.
By Sunday morning the large and impressive upper level system just to the north of the Great Lakes will continue to shift to the south and east, spawning a surface low pressure system well to the north of our area. While direct impacts in the form of precipitation are unlikely from this low pressure area, it will help to increase low to mid level clouds over much of the Northeast. Additionally, this surface low to our northwest will also increase southerly winds over the area, leading to slightly warmer highs during the day. Temperatures should be able to reach back into the lower to middle 40’s across much of the NYC area, with upper 30’s likely across the interior-which will be on the order of 5-10 degrees above normal. Finally, a cold front associated with the area of low pressure to our north will move through during the evening and overnight hours of Sunday. At this time it appears that the cold front will likely be significantly lacking in moisture, making this frontal passage a dry one. The front will also usher in colder middle to lower level temperatures once again, bringing lows back down into the lower to middle 20’s.
This evenings NAM model showing the progression of warmer surface temperatures into Sunday, followed by another cold front Sunday night (COD Weather)
Potentially Messy Storm System and Major Arctic Blast Set to Impact the East Next Week
As we highlighted back in our last update, another northern stream shortwave trough will be heading into the Northern Plains by Monday morning that bears watching.
This system will be pushed well to the south by Monday evening as a deep upper level system that is directly associated with the tropospheric polar vortex makes its way into Southern Canada. As this deep and highly-anomalous system continues it’s push into Southern Canada on Tuesday, precipitation will likely break out over portions of the Southeast and extending up into the Ohio Valley along a frontal boundary. As this boundary approaches the Northeast by Tuesday night, large scale upper level divergence will be on the increase over much of the East Coast. This would support the development of a quickly intensifying low pressure system near or over the Northeast late Tuesday and into early Wednesday morning-but this is where the reliable model guidance begins to diverge.
This afternoon’s European model showed a substantial amount of energy swinging through the Mid-Atlantic states, causing the development of a rapidly intensifying surface low that moves inland over portions New England by Wednesday morning. Such a solution would bring some light rain/snow during the onset, with a quick flip to more significant mixed precipitation as the low pressure rapidly strengthen and drags in much colder air from the northwest. The rest of this afternoons guidance does indeed show a low pressure system forming along the frontal boundary, but disagree on the exact location and magnitude of deepening of this potential system. Needless to say, these factors will play a major role in determining the overall outcome of this system.
At this time, even a compromise of these solutions (weaker vs. stronger) would bring the potential for some impactful weather to the area Tuesday/Wednesday AM. We will need to closely monitor this system over the next few days as new data comes in.
12z European Ensembles showing a significant amount of members developing a strong secondary area of low pressure over the Northeast on Wednesday AM (WxBell)
Regardless of what the Tuesday/Wednesday system does, virtually all available model guidance and their respective ensembles agree that the westernmost lobe of the tropospheric polar vortex will swing into the Northern Plains and Great Lakes by Wednesday night. This will cause a very impressive Arctic airmass to blast its way into the northern tier of the country-with potentially record breaking temperatures for the Great Lakes region. As this Arctic airmass heads into the Northeast, early indications are that it may begin to moderate just enough that portions of the Northeast are spared from record cold. However, the potential will certainly be there for an extremely cold end to next week with high temperatures struggling to break out of the single digits, in addition to dangerous wind chills well-below zero.
Diagram showing an Arctic high pressure system moving into the Central US during the middle of next week, dumping extremely cold temperatures into the CONUS (White colors denote areas that are below 0F)
We’ll continue to update you on this Arctic outbreak as well as the potential storm system for mid-week!
Have a great weekend!
-Steven Copertino
Multi-faceted winter storm to impact the region this weekend
Highlights: After light snow today, a more notable winter storm approaches for the weekend, with arctic air moving in behind it and a colder and active weather pattern to follow.
Good Evening!
Today has been a rather gloomy and cold January day across much of the Northeast as the weak system that dropped some light snow across portions of the metro area this morning continues to quickly head offshore. As discussed in previous updates, this system was likely to only produce a trace to one inch of snow over the area, and that is exactly what has been reported as of this afternoon.
As the snow departed late this morning, mainly cloudy conditions remained overhead with mid level flow increasing out of the southwest. These southwesterly winds have allowed for a slightly more marginal airmass to overspread the area today. Coupled with the persistent cloudy conditions, this caused highs today to rise into the middle to upper 30’s across much of the forecast area-with 40’s reported closer to the coast. Cloudy and slightly above-normal temperatures will continue into the evening hours before a mid level disturbance passes well to our north. This system will be accompanied by a cold front that should help to clear out some of the remaining clouds tonight and usher in colder temperatures from our northwest.
Lows will likely drop back down into the lower to middle 20’s for the majority of the area this evening, which will be right around normal for this time of year.
This evenings high resolution NAM model showing lows backing down into the 20’s and lower 30’s for the NYC area
Complex and Impactful Winter Storm This Weekend
While tomorrow (Saturday) will likely start off quite calm and clear, the winter storm we have been talking about for nearly ten days now will be quickly approaching from the west. By 8 am, the storm will be centered over the Tennessee valley, with moderate to heavy snow expanding into much of the Ohio Valley. While the main shortwave trough associated with this system will not be able to completely interact or phase with the larger system over Canada, it does appear that there will be just enough of an interaction to keep the bulk of the heavy snow well off to the north and west of the immediate NYC area.
As we head into Saturday afternoon, the surface low over the Tennessee valley will be picking up steam and intensifying. As it does so, a large area of warm/moist air will begin to stream northward over much of the Southeastern states. All of this warm and moist air just above the surface will collide with a strong Arctic high pressure system over southern Canada and cause a moderate to heavy band of snow to develop over portions of New York and Pennsylvania. Light snow will likely begin to move into portions of Eastern New Jersey by 3-4 pm, with the snow quickly picking up in intensity over time. This band will continue to head east by 4-5 pm, likely overspreading the entire metro area by that time. All of the warm/moist air moving into the Northeast and colliding with colder air to the north will cause an enhanced area of lift within this band of snow, which could push snowfall rates into the 1-2″ per hour range–especially over portions of EPA, SNY, and NW NJ.
This area of moderate to occasionally heavy snow will likely continue into the evening hours of Saturday. It is at this time that precipitation types will start to become an issue. Due to the SW to NE orientation of this system thanks to the modest interaction with the system located over Canada, warmer air in the lower levels of the atmosphere will begin to overspread much of Southern and Central New Jersey, and eventually into the immediate NYC area. While the overall track of this system and the actual degree of interaction with the aforementioned Canadian system will determine the timing of this changeover, much of the metro area will likely see a change to a mix of sleet, freezing rain, and plain rain by 11 pm to 1 am. Locations off to the north and west of the immediate NYC area could potentially hold onto pure snow few a few more hours, causing a steep snowfall gradient to develop over our area.
Warm/moist air will continue to push further north into the forecast area overnight on Saturday and into the early morning hours of Sunday. Locations around the immediate New York City area have a good chance to flip to all rain at this time, with locations to the north and west potentially changing over to a dangerous mix of sleet and freeing rain. In fact, the freezing rain threat will be quite high over this area, with up to a tenth to a quarter of an inch of freezing rain possibly falling by Sunday morning.
The combination of moderate to heavy snow and freezing rain will likely cause very significant travel disruptions north and west of the city on Sunday morning.
Our latest total snowfall accumulation map for Saturday and into Sunday morning. The hatched area denotes the potential for significant freezing rain and sleet accumulations.
Dangerous Flash Freeze Possible Sunday and into Monday
Precipitation will likely still be ongoing by 8 am Sunday morning, with rain mostly expected for the vast majority of the forecast area as the surface low pressure system will likely be over Southern New Jersey at this time. Despite the change to plain rain, much colder air will be quickly approaching the area as the surface low begins to pull to our east during the afternoon hours on Sunday. Temperatures will quickly fall well-below freezing and into the lower to middle 20’s from west to east, likely causing any standing water to refreeze. Any residual precipitation over the area will need to monitored, as a flip to snow would be possible.
Regardless, true Arctic air will work blast through the entire forecast area by Sunday night, with lows dropping down into the single-digits! Winds will also be quite strong behind this system, with gusts up to 35 mph possible. If significant ice accumulations do occur over portions of the area, then there could be an enhanced threat of power outages Sunday night.
The colder than normal weather pattern is very likely to remain in place into next week, as a piece of the polar vortex fractures and settles in to the north of the region. This will keep cold and potentially active weather in the forecast as we move toward the back half of the week, and especially into next weekend.
We will Continue to provide updates on this storm over the next day or so. Please stay tuned to our social media accounts for up to the minute information!
Thanks for reading!
-Steven Copertino/John Homenuk