Steven Copertino

Snow and sleet to cause travel concerns Tuesday

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Good evening!

Today has been a rather dull and cold day across much of our area as an upper level disturbance off to our west continues to produce widespread overcast. Some light to moderate areas of snow have been reported over southern portions of New Jersey today. The main story for our area continues to be a more impactful period of moderate to heavy snow that will gradually work its way into the Mid-Atlantic and Northeast by early Tuesday morning.

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Steven Copertino

Light Mix Moves Through, Watching This Weekend

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Good evening!

Today has been a rather cold and clear day over the entire Northeast, especially when compared to the past week or so. Stout northwesterly flow has ushered in a much more cold and dry continental Arctic airmass over the entire area, which has kept high temperatures in the upper 20’s to lower 30’s-with some mid 30’s over SNJ and Long Island.

The large, but disorganized mid-level system that we have been going over for the past week has begun to gradually edge into the Northeast this afternoon and has been producing some very light sleet and snow across portions of Pennsylvania and New York. This area of precipitation looks rather impressive on radar, but surface observations confirm that there has been barely any precipitation reaching the surface-even under the heaviest of radar echoes. This is mainly due to the very dry and dense Arctic airmass still in place through the lowest ~500 feet of the atmosphere. As the snow falls towards the ground it is evaporating in addition to transitioning to sleet. Since radar beams gradually increase with height the further out from the radar site you go, these beams are hitting this area of transitioning precipitation, causing the precip to look more intense than whats being observed at the surface.

Regardless, the narrow band of mixed precipitation will continue to gradually head east over the next few hours–likely impacting the metro area just in time for the evening commute. Due to the very unimpressive forcing and low level dry air in place, mainly sleet and freezing rain is expected for the immediate metro area with a few broken flakes mixing in at times. As we head into the NW suburbs and into portions of SNY, there could be more of a snow/sleet mix, with some very light accumulations on colder surfaces.

Regional Radar Mosaic

This evenings latest hi-res radar showing an area of light mixed precip working its way into the area 

Light Mix Lingers Into Tuesday Morning

Continue light mixed precipitation mainly in the form of sleet, freezing rain, and rain will be possible as we head into the late evening and overnight hours of Tuesday as the area of high pressure currently situated over New England shifts offshore. This will cause low level winds to become more southerly in nature and will lead to an increase in available moisture. As always, a shift to more southerly winds also means an increase in surface temperatures over the entire area.

Locations over SNJ will be the first to really feel the effects temps rising above freezing, which will cause a changeover to all rain before 5 am. Since this current airmass has been rather stubborn, it may take some time for the warmer air to make its way north of NYC, but the changeover will continue through the overnight hours and into the very early morning hours tomorrow. At this time, locations north and west of the New York City area have the best chance at seeing prolonged periods of light sleet and freezing rain lasting through 5 am. Any accumulations with this system will be quite minimal, with the potential for some slippery roads by the time we reach the AM commute.

Temperatures will then quickly rise to above-freezing for the entire area around 8 am tomorrow morning as the last of the precipitation swings through. Though some dry air is expected to develop aloft as the main upper level system moves through tomorrow afternoon, skies should remain mostly cloudy with a chance at some light rain showers or drizzle lasting into the evening hours. Highs will likely reach into the lower to middle 40’s for the entire forecast area as cloudy conditions and mild low-level temps take over.

Things get a little more interesting towards the overnight hours of Tuesday as strong mid-level energy and residual moisture move through the Northeast with an associated cold front. This will create the potential for some increased precipitation to breakout after midnight. Given the steep changes in temperature with height and weak instability, there may even be some heavy spots of sleet and graupel that develop over portions of Pennsylvania and New Jersey. Otherwise, tomorrow night will be another mild night, with lows only getting down into the upper 30’s to lower 40’s with winds picking up significantly after the cold front moves through.

HRRR Sim Rad

This evenings HRRR model showing the light area of mixed precipitation impacting our area later this evening and into the overnight hours

Attention Turns Towards This Weekend

Mainly calm and cold conditions will remain in place across much of the east for the rest of this week and lasting into this weekend. Northwesterly flow will be in place during this time, leading to below-normal temperatures and mainly dry weather. However, there are signs that we may have to watch a system coming out of the Southern Plains by Friday afternoon. The past few runs of the reliable computer models and their ensembles have shown that this piece of energy may try to interact with an incoming strong piece of energy from Canada. As of right now there are two scenarios being shown with this setup:

–The first (and least likely as of now) is that the shortwave trough over the Plains will phase with the incoming Canadian shortwave trough on Saturday. This would cause a large area of heavy snow to develop from the Midwest to the East Coast on Saturday/Sunday with significant impacts.

–The second (and most likely as of now) is that the shortwave over the South is not able to cleanly phase/interact with the incoming shortwave over Canada. Instead, the Canadian shortwave acts to suppress this system and the vast majority of the precipitation stays to the south of the NYC area, causing little to no impacts.

It is very important to note that we are still quite a while out, and significant changes are likely to occur between now and Friday. The overall evolution of this system will depend on the exact timing and location of each system and we will have to watch how these systems behave over the next four days.

GFS 500mb

This mornings GFS model which was the most aggressive model at the time. This model was phasing both the feature over the Plains and over Canada to produce a large snowstorm for the Northeast

Thanks for reading and have a great night! We’ll have an update on Wednesday!

-Steve Copertino

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Steven Copertino

Rain Exits Tonight, Active New Year’s Week Ahead

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Good evening!

As expected, today has been yet another dreary and rainy Friday for much of the East Coast. In fact, this has been the third Friday in a row that has featured heavy rain and mild temperatures. Unfortunately, that streak looks to continue, but we will have more on that later.

As of 5 pm, most of the left-over heavy rain was located just off the New Jersey coast and gradually moving to the east/northeast. While most of the metro area will begin to see precipitation tapper off from west to east in the next few hours, portions of eastern Long Island will likely see periods of moderate to heavy rain until the early evening hours. Stout southwesterly flow has been over the Mid-Atlantic and Northeast since early this morning, and temperatures have since been able to shoot up into the middle to upper 50’s across much of the area- with even some 60 degree readings showing up over portions of southern New Jersey. Needless to say, these highs are well-above normal for this time of year, with readings coming in anywhere from 18-24 degrees above-normal!

Mild temperatures and the chance for a light shower or two will last well into the overnight hours tonight as the cold front associated with this system lags well off to the west over the Ohio Valley. Lows tonight will be very mild, with temperatures staying in the middle to upper 40’s for much of the area. Temperatures across southern New Jersey could stay well into the 50’s into the early morning hours of Saturday.

In addition to the chance for some leftover showers this evening, low-level moisture will also contribute to some foggy conditions across the region before more windy conditions take over. Please use caution while traveling tonight, as some locations could see locally dense fog.

7-day forecast

~Updated Weekly Planner~

Cold Front Finally Arrives Saturday, Another Storm Develops Late Sunday

Saturday will likely start off rather mild across much of the Mid-Atlantic and Northeast as a cold front to our west slowly limps towards our area. High temperatures will likely be reached during the early morning hours, with readings likely reaching the middle to upper 40’s–with 50’s possible closer to the coast. Leftover low-level moisture will likely contribute to partly cloudy skies during the days, but should gradually decrease as we head into the late afternoon and evening hours. The much-anticipated cold front will finally move through our area by 3-5 pm, which should feature increasing winds, sharply falling temperatures, and decreasing dewpoints. These gusty winds and decreasing temperatures will last into the evening and overnight hours, with lows getting back down towards seasonable levels. Expect temperatures to bottom out in the middle to upper 20’s, with lower 30’s in and around the city.

Thankfully, Sunday looks to be the “gem” of this forecast period as it will feature mostly sunny skies and seasonable temperatures in the middle 30’s to lower 40’s for the entire forecast area as an area of high pressure build in over the east. Mid-level flow will be increasing from the west, so we cannot rule out a few passing clouds during the day, but the overall forecast for Sunday looks quite pleasant. Unfortunately, our next storm system will be gathering out over the Southern Plains late in the day Sunday night, with showers and thunderstorms likely beginning to increase over the Arklatex region.

NAM 3km Temps

This evenings NAM model showing the progression of the weak cold front set to move through the area on Saturday

Dreary and Dismal New Year’s Eve Likely

At this time, it is unfortunately looking likely that the system that will develop over the South late Sunday and into Monday will impact the New York City area on New Year’s eve with the potential for yet another chance at heavy rain-a fitting end to one of the wettest years in record. Clouds will gradually increase during the afternoon hours on Monday as yet another strong push of southwesterly flow moves into the region. As the day progresses into the late afternoon and evening hours on Monday, the main surface low will begin to push through the Ohio Valley, with a large area of steady rain overspreading the region by 5-8 pm. Conditions will continue to gradually go downhill as a low-level jet transporting moisture from the Gulf of Mexico will be overhead by this time as well. This will set the stage for heavy rain to potentially move through the NYC area just in time for the New Year’s celebration in Times Square as temperatures begin to rise into the middle to upper 40’s. The rain should gradually begin to tapper off from west to east during the very early morning hours of Tuesday, with mild temperatures holding on throughout the night.

As if things couldn’t get any more bleak, this afternoon’s models have been keying in on yet another disturbance making its way towards our area late next week just in time for (you guessed it!) Friday. If this system were to happen the way the models show, this would be the fourth Friday in a row which featured at least moderate to heavy rain!

Details for this potential system are very hazy at this point in time, but we will continue to monitor it over the coming days!

ECMWF 6-hour Precip

This afternoons ECMWF model showing yet another heavy rain event for New Year’s eve

We hope everyone has an excellent weekend and we will have an update on the upcoming system on Monday! 

Steve Copertino

 

John Homenuk

NYC Area Forecast: Another Rainy Friday

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Briefing: Rain expected this morning, with periods of heavy rain through the early afternoon. Localized flooding possible.

If you’re thinking it has rained on Friday a lot recently, you are thinking correctly. It has rained on the past three Fridays, actually, and we’re gunning for four today. A low pressure system moving into the Great Lakes is bringing warm and and plenty of moisture with it, and the result will periods of showers throughout the morning today. These are expected to continue for the majority of the morning hours.

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