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John Homenuk

Anomalous cold’s swan song, moderation lies ahead

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Welcome to Five Minute Drill, our new segment where we discuss the weather without bias or favoritism on a local, regional, and national scale as the weather suggests. In the week ahead, we’re discussing the movement of bitter cold away from the Northeast states, but the prevalence of a few weak atmospheric disturbances that may lead to wintry precipitation on Monday evening. We touch on where we’ve been over the past few days, why things are changing, and briefly discuss a Northern Plains winter storm later in the week.

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Steven Copertino

Brutal Cold Grips Northeast, Changes Are Coming Next Week

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Good Evening! 

Yesterday we saw an extremely impressive Nor’easter impact much of the Northeast with heavy snow, highs winds, and extremely dangerous coastal flooding for the majority of the day. Snow totals varied quite a bit from west to east, but the highest totals for the region occurred from portions of eastern New Jersey, Long Island, Connecticut, and into New England, where amounts in the 10-20″ range were common. Totals over central and western New Jersey were lower, with numbers generally in the T-8″ range, as was common in PA and SNY. Overall, this was a very impressive and possibly historic storm due to its ferocity and sheer amount of power. Conditions came together in the atmosphere in just the right way to let this storm go from a rather weak 1010mb system off of Florida, to a monster 951mb blizzard off of the Delmarva coast. This extreme pressure drop contributed to the very strong winds we saw over the entire east coast and continue to see today and this evening.

As the storm pulled away last night, a deep Arctic airmass dove down from northern Canada and has caused temperatures to once again drop into the lower to middle teens across much of the tri-state area. Much colder reading were seen over portions of New England, with some locations staying 10-12 degrees below zero! A strong pressure gradient will continue to exist between the Arctic area of high pressure over southern Canada and our blizzard that continues to move over portions of southeast Canada. Winds tonight will continue to gust into the 15-30 mph range and when coupled with lows in the only a few degrees above zero in the immediate NYC metro area, wind chills will become very dangerous. Wind chills will likely drop into the -15 to -25 range for NYC and the immediate north/west suburbs and -20 to -30 for locations in Southern New York and Northeastern PA. These kinds of readings can cause frostbite within 20-30 minutes of exposure, so please use caution if you must go outside late tonight and into the overnight hours and make sure to layer-up!

Animation showing the progression of tonight's expected wind chills from the HRRR model. Readings will be at their lowest around 6-8am Saturday

Animation showing the progression of tonight’s expected wind chills from the HRRR model. Readings will be at their lowest around 6-8am Saturday

This Weekend 

Saturday looks to be yet another brutally cold and well-below normal day across the Northeast as Arctic high pressure builds into the region. Conditions should start off very cold and cool as mid-low level dry air takes over and limits any potential for any clouds besides upper-level cirrus. Winds may attempt to subside a bit during the day, but will likely still gust into the 20’s, which will still bring brutal wind chills in the -20 to -10 range during the early morning and afternoon hours. Highs across the NYC metro area will likely struggle to get out of the single-digits, with lower to middle teens expected to the south over portions of Pennsylvania and New Jersey. Frigid and dry conditions will last into the evening and overnight hours as we see lows drop off once again in the 5 to -10 range. Winds will continue to diminish, but wind chills will still be able to stay in the -10 to -20 range pretty much area-wide. Again, take the necessary precautions if you have to head outside tonight and Saturday night.

Sunday will be another cold and dry day across the Northeast as the Arctic high pressure system is directly overhead. Mid level dry air should ensure that conditions stay mostly sunny, with only a few passing high clouds expected. Despite the Arctic high being overhead, mid level flow will begin to modify ahead of a developing system in the Plains. This should cause temperatures to not be as brutally cold, with highs in the upper teens to middle 20’s expected across the entire area. Lows will likely not fall all that much as the high pressure system begins to exit off the Mid Atlantic coast and the entire region sees return flow from the south.

Animation showing the last of the brutal cold moving through the Northeast tonight and Saturday

Animation showing the last of the brutal cold moving through the Northeast tonight and Saturday

Major Changes Likely By Next Week

After one of the most impressive and longest cold-spells in recent memory for the Northeast, one would think that things would eventually have to break down. Last week I asked this same question, but now it seems like the brutal cold will indeed gradually fade to relatively warmer conditions across the east. After the Arctic high pressure system exits the country by Sunday night, the upper level flow will become more east to west based, which is a strong departure from the highly amplified pattern we have been accustomed to over the previous 10 days. This pattern should allow for multiple shots of warmer air from the south and west to overtake the Northeast, with highs in the 30’s and 40’s likely to make a return. As of right now, there does seem to be a chance that we could get temperatures into the upper 40’s and possibly lower 50’s, but this is around a week away and will likely need to be revisited next week. Regardless, while we may see slightly above-normal temperatures at times, we do have to keep in mind that this is still January and the potential for snow will always remain present. Would could see a rather active period with above normal precipitation through the middle of January as deep tropical moisture may occasionally try to nose its way into the country. We will be watching this potentially warmer and wet period closely over the next couple of days and will provide updates when they are available!

This afternoons ECMWF ensembles showing the potential for above-normal temperatures next week across the central and eastern US

This afternoons ECMWF ensembles showing the potential for above-normal temperatures next week across the central and eastern US

Have a great weekend!

-Steve Copertino 

Steven Copertino

Another Round of Records May Fall, Any Chance of Warmer Weather Soon?

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Good Afternoon! 

We hope everyone out there has been bundled-up over the past couple of days as we continue to endure a record-breaking temperatures across much of the Northeast. Today was a little warmer than yesterday, but warmer in this sense is still relative. Temperatures were stuck in the upper teens to middle twenties across the entire New York Metro area, with some middle to lower teens further north and west of the city. The same stout northwesterly flow in the mid levels of the atmosphere are still prevalent across the entire northern tier of the country, which continues to pump dry, Continental polar air into the country. Mainly dry conditions can be expected for the rest of the afternoon and into the evening hours before a weak shortwave trough begins to move into the Ohio Valley later tonight. This system looks to be too weak and too far west to really bring any precipitation into the region, but we should see an increase in mid to upper level clouds during the overnight hours. These clouds will work to dampen the maximum amount of radiational cooling we can achieve, but lows tonight will still be downright frigid once again. Middle to lower teens are expected tonight for the immediate NYC area, with single digits likely just to the north and west.

This afternoon high resolution visible satellite imagery, regional radar mosaic, and surface observations showing yet another bitterly cold day across the entire Northeast.

This afternoon high resolution visible satellite imagery, regional radar mosaic, and surface observations showing yet another bitterly cold day across the entire Northeast.

Light Snow Possibly Saturday

The weak shortwave trough that we mentioned earlier will continue to move east overnight and into the early morning hours on Saturday, likely bringing some very light snow to portions of the Mid Atlantic states. This system will be seriously moisture-starved, but any snow that falls will be high-ratio snow. This means that even if you see around .1″ of liquid, you could still manage to see about 1.5″ of fluffy snow. Scattered light snow should begin to overspread portions of eastern PA and NJ by the early morning hours tomorrow, with more concentrated bands possible over MD/DE. Light snow should then move over the rest of the area by the late morning and afternoon hours as a secondary low begins to develop just off of the Mid Atlantic coast. Once this secondary low begins to mature, snow should be ending over much of NJ and points west, with trace to maybe an inch of snow possible. Our secondary low should have more of an impact further east over portions of Long Islands and Connecticut where it should act to rejuvenate snow over those areas and possibly add a boost to the intensity. Slightly higher accumulations may be possible in these areas, with 2-4″ possible before the low quickly races off to the east and precip shuts down by 8-10pm. Note: Due to the extensive dry air ahead of this system, we could see prolonged periods of virga over the area leading to the possibility of little to no snow at all in some places. 

The rest of the night looks to be very cold, with scattered snow showers possible over much of the Northeast as another shot of Polar air moves into the region overnight. Lows will drop down into the middle to lower teens around the city, with single-digits likely to the north and west.

This afternoons RPM model showing a light area of snow overspreading the region on Saturday morning

This afternoons RPM model showing a light area of snow overspreading the region on Saturday morning

Sunday will compete to be the coldest day of the year on the last day of the year as Polar high pressure builds into the Northeast during the morning hours. Highs during the day will be bitterly cold, with readings likely in the middle teens to right around 20. Strong northwesterly flow should keep enough dry air in the column to keep any clouds at a minimum. Dry and cold weather can be expected to last into the evening hours, just in time for New Years Eve. This should be one of the colder New Years Eve’s in recent memory, with the potential for quite a few records to fall across the Northeast. NYC may come very close to breaking a record low minimum temperature of around 9F.  Readings across the entire area will be exceedingly cold, around the low teens to single digits area, with wind chills a good 5-10 degrees colder. We would seriously advise against being out for a prolonged period of time in this kind of cold, but if you are planning on it, make sure to wear multiple layers of clothing and cover up any exposed skin. Bare skin will be very susceptible to frost-bite during the evening hours!

National Weather Service forecasted lows on New Years Eve, with the circles representing possible records being tied or broken!

National Weather Service forecasted lows on New Years Eve, with the circles representing possible records being tied or broken!

New Years Day & Beyond! 

We look to start off 2018 with another frigid and potential record-breaking day as very strong northerly flow dumps the remaining Polar air right into the Northeast. Most locations near the City will likely not be able to reach the 20’s, with middle to upper teens likely as highs during the day. Locations even further to the north and west will also struggle to see highs come out of the single-digits, making Monday an excellent day to just stay inside and enjoy a nice warm beverage!

Will things improve and warm up later next week? The short answer is absolutely not. We could see temperatures briefly come back into the upper 20’s, but most of the Northeast may be stuck below-freezing for at least the next 10 days or so! To further complicate things, a coastal storm may past to the east of the region on Wednesday, which would bring down another extremely cold airmass from deep in Canada. At this time, this system appears to have a low chance of impacting the East, but we will be monitoring this system very closely since some of yesterdays guidance did show the potential for a rather high-impact storm if all the pieces come together at just the right time and place (thread the needle type of system)

This afternoons ECMWF model showing a reload of the cold weather with a shot of true Arctic air next week.

This afternoons ECMWF model showing a reload of the cold weather with a shot of true Arctic air next week.

Have a great weekend and we’ll see you in 2018!

Steve Copertino