Unseasonably cold and relatively calm conditions have dominated through the first half of this week. Temperatures look to rise only a few degrees through Friday before we have to watch for our next rain threat later on this weekend!
As we promised last week, much of the Northeast is now firmly entrenched in a cool and relatively quiet pattern that looks to stick around until at least the later half of this week.We kicked off the work week fitting that mold quite well as area of weak high pressure began to build in from Canada and over into portions of New England. This high pressure system ushered in a reinforcement of very dry lower to mid-level air that originated all the way from portions of the Arctic. With this very dry airmass in place, virtually the entire day has been clear across the Northeast, with the exception of a few spotty clouds further off to the north and west of the city. Given the already cold airmass in place, we saw high temperatures once again come in below the climatological average for this time of year, with highs ranging from the middle to upper 30’s during the afternoon hours. This evening will be yet another in a long-running series of cold nights as light winds and a dry/cold airmass allow for very efficient radiational cooling to take place.
Lows should be able to sink down into the middle to upper 20’s for most of Northeast NJ, Southern New York, and portions of Connecticut -with locations well to the north and west possibly slipping into the teens tonight.
Otherwise, lows in the city and along the coast should be a little warmer, with temperatures staying in the upper 20’s to lower 30’s
This evenings hi-res NAM model showing lows getting well-below freezing once again tonight for much of the area
Those waking up for the AM commute Tuesday morning should expect more of the same, with very clear but also cold weather expected. Morning temperatures in and around the New York City area will likely be in the middle to upper 20’s-with lower 30’s likely in the city.
Yet another moisture-starved shortwave trough will be moving through portions of southeast Canada during the early afternoon hours, which should help to keep very dry/stable conditions over the Northeast. This dry air will allow for much of the region to stay mostly sunny, with the usual spotty clouds expected well off to the north and west over portions of New York state and Pennsylvania. Highs tomorrow afternoon will be quite similar to today, with temperatures staying in the middle 30’s for the majority of the region. Some readings closer to the coast may approach the lower 40’s, but it will still feel quite cool. As we head into the early evening and overnight hours, the weak shortwave trough that was previously located over portions of southern Canada will quickly move through the Great Lakes and into the Northeast. While this system is very dry and limited in its precipitation potential, there may be an outside chance at some flurries or light snow showers for locations to the north and west of the city. Lows tomorrow night will once again range from the middle to upper 20’s for the majority of the area, with the typical colder readings for locations to the north and west.
Wednesday should be another uneventful day across the Northeast as the area of high pressure that has been in control of our weather begins to gradually head to our east over eastern Canada. Stout northwesterly flow will be in place for the morning and afternoon hours which will allow for the same mostly sunny and cool conditions. Highs will likely be somewhat warmer during the day Wednesday when compared to Monday and Tuesday, but should still be slightly below-normal for this time of year with middle to upper 30’s likely for much of the area. The area of high pressure located over eastern Canada will begin to sink to the south and over New England on Wednesday night, which should provide another great chance at substantial radiational cooling. Expect lows dip down into the middle to upper 20’s for the area, which teens for inland locations.
As high pressure continues to sink to our east Thursday morning, another sneaky shortwave trough will be rapidly moving through the Great Lakes and into the Northeast. While this shortwave trough is relatively small and dry compared to its surrounding environment, the high pressure edging off the New England coast may be able to give this system a “boost” as the mid-level flow will be coming from the Southeast US instead of Canada. This could allow enough warm air advection to creep into the Northeast/Mid-Atlantic and interact with the dynamics of this shortwave to produce some light rain/snow showers (or even graupel) over the area on Thursday afternoon/evening.
Right now this solution isn’t set in stone and will have to be reviewed, but it’s something to keep an eye on in an otherwise boring pattern. With the aforementioned return flow coming from the south during the day on Thursday, we should see temps finally get into the upper 30’s and lower 40’s area-wide, though if the shortwave trough trends stronger/more moist, we could really put a cap on just how “warm” temperatures get Thursday afternoon.
This evenings NAM model showing the small, but energetic “clipper” system approaching the Northeast on Thursday followed by a larger system taking shape in the South
As we head into late Thursday/Friday, a shortwave trough from the Pacific Northwest will drop into the Rocky Mountain region and begin to phase with another piece of energy over northern Mexico. The overwhelming majority of this afternoons model guidance indicates that the result of this interaction of these two systems will yield another large area of rain breaking out over the South just in time for this weekend. As this system continues to the east during the day on Friday, it will likely “cut off” from the main jet stream, which will allow it to slowly make progress over the Southeast US while dumping very heavy rainfall. Things get interesting on Saturday as we see a similar pattern to this past weekend, with confluence in southeast Canada, and a storm to the south.
However, this time around there is no injection of cold air ahead of the storm and the confluence over Canada isn’t nearly as strong as it was this past weekend. This should allow for the upper-level low to very slowly move to the east and cause an impressive low-level jet streak to develop over the Southeast US and extend into the Northeast by Friday night. This low-level jet will be capable of transporting a very moist maritime tropical airmass from the Caribbean along the East Coast by Saturday morning, which will likely result in very heavy rainfall-and possibly even some flooding concerns. The evolution of the storm then becomes a bit more uncertain as we head into late Saturday and Sunday-with the potential for this upper-level low to linger in the East, which could prolong the rain/shower threat until Sunday.
12z ECMWF model showing a very healthy and moist low level jet extending from the Southeast US and into portions of the Northeast (AccuWx Pro)
We’ll be keeping an eye on this potential system over the next few day’s to monitor any potential hazardous weather that may accompany it, so make sure to check back soon for further updates!
Have a great night!
Steve Copertino
Good afternoon!
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Things have once again turned quite calm over much of the Northeast today after a weak upper level disturbance moved through last night and produced some light snow well to the north and west of the New York City metro. Strong northwesterly flow behind this system has cleared out remaining moisture in the atmosphere and has replaced it with cold, dry Arctic air. Despite the cold mid level temperatures, clear skies have allowed for temperatures to rise into the middle to upper 30’s over much of the Northeast, with lower 40’s showing up in the city and portions of southern New Jersey.
The remainder of this afternoon will feature much of the same, with mostly sunny skies and light winds. There may be a chance at some more isolated snow showers if you’re traveling to eastern Pennsylvania and southern New York, but these should be quite tame. As we head into the evening hours and overnight, yet another Arctic shortwave will be passing to our north, which will provide a fresh injection of very dry and very cold air. Additionally, an area of high pressure will be edging it’s way into the Ohio Valley and Northeast. Given the dry air, fresh cold mid to upper level, and light winds, we fully expect radiational cooling conditions to be near-ideal tonight. This should allow overnight lows to drop well into the 20’s and teens over much of the Northeast, with even some single-digit readings possible. If you’re heading out tonight, definitely bring a heavy coast as it will feel more like January than December!
This afternoon’s ECMWF model showing surface temperatures 12-20 degrees below normal Saturday morning (AccuWx Pro)
Snowstorm passes well to the south later this weekend
As we talked about back on Wednesday and earlier this week, the storm we have been watching for the better part of the last ten days now appears to slide well to the south of the Northeast during the day on Sunday and into Monday. The models have trended even stronger with the confluence over eastern Canada over the past couple of cycles, which has caused an even greater shift to the south.
It now appears that places like Washington DC are unlikely to see any meaningful precipitation from this storm, while locations in southern Virginia and North Carolina may face a very impactful winter storm, with substantial snowfall and dangerous ice accretion. As of this update, the National Weather Service is forecasting snowfall totals of up to 12-18″, with locations in the mountains of NC likely to see over two feet of snow by Monday. Those who live in this region should be prepared to have normal operations and routines severely disrupted at least through Monday night-if not longer.
Back up north in our neck of the woods, Sunday should remain cold and clear, with a chance of increasing clouds towards sunset. Both Saturday and Sunday should feature highs in the middle to upper 30’s, with lows well into the 20’s. Locations well to the north and west should even be able to dip back down into the teens Saturday night.
Loop of this afternoons 3km NAM model showing the significant storm passing well to the south of the region this weekend. Heavy snow will be likely for portions of the Mid-Atlantic and Southeast
Quiet conditions and below normal temps persist into next weekend
After this weekend’s storm exits off the Southeast coast Monday night, we should see very quiet and cool conditions for the majority of the next week. Temperatures will likely remain 5-15 degrees below normal along the east through Wednesday, with lows sticking well-below freezing for the Northeast.
However, by the time we get to around Wednesday/Thursday, a large and energetic upper level disturbance will be moving into the Rocky Mountains. This upper level disturbance could be our next shot at some precipitation by the time we get to next weekend. At this time the models are showing an area of low pressure developing over the Midwest, which would bring a significant amount of moisture and warmer air up through the southern states and eventually into the Northeast. This would likely result in an increased chance for rain for the NYC area next weekend, but we’ll certainly be keeping an eye on this potential system during the course of next week.
500mb height anomalies from this afternoons ECMWF model showing an unusually deep closed upper level low over the south, with an area of ridging over the East.
Have a great weekend!
Steven Copertino
Good Evening!
The snowstorm that we have been discussing for the past week has finally exited the region after dropping light to moderate snow for most locations. Due to onshore flow, precipitation mainly started out as rain over portions of New Jersey and southern New York, but colder air associated with the frontal system over Pennsylvania gradually made its way south. This caused the rain to flip to snow over much of the area, with coastal sections of New Jersey and Connecticut seeing plain rain. Rain was also quite common over the majority of Long Island this afternoon, as winds from the east kept temperatures in the middle to upper 30’s. Snow totals around the New York city metro area were generally light with a trace to three inches common for most locations. Totals over the southern half of New York state were a bit higher, with 6-10″ being reported due to snow from the frontal system as well as the weak coastal low. All major NYC airports reported less than one inch of snow as of 4pm, so travel likely will not be impacted all that much tonight.
This evenings latest RTMA 2m temperature analysis, surface observations, and regional radar mosaic showing the snowstorm exiting off the coast
Conditions this evening and into the overnight hours will be generally calm as drier air begins to work in at all levels of the atmosphere. This should pretty much kill any chance of residual snow showers, but there could be a brief flurry or two mainly to the north of NYC. Winds will begin to increase from the north and northwest as another coastal low begins to strengthen well to our south. This system will have absolutely no impact on our weather this evening outside of some occasionally gusty winds. The northwesterly flow in the mid levels of the atmosphere combined with the fresh snow pack over much of the Northeast will lead to some pretty cold temperatures overnight, with lows getting down into the upper teens and low 20’s across the immediate NYC area, with locations to the north and west likely seeing lows well into the teens and single digits. This will cause a chance for some of the snow that melted this afternoon to quickly refreeze on untreated roads, so please use caution when traveling.
Snow totals from around the immediate NYC area courtesy of the NWS in Upton, NY
Warmer and Calm Conditions Through the Weekend
Thursday will be the last cold day across the Northeast for a bit of time as mid level ridging begins to build quite a bit over the central part of the United States tomorrow. Highs will likely remain below freezing during the day, with readings staying in the middle to upper 20’s for northern locations, with lower to middle 30’s possible south of New York City. A weak shortwave trough looks to pass through portions of southern Canada by
Friday afternoon, and this could spark some light snow over portions of northern New England, mainly over ski country. Otherwise, mid level flow from the west should cause temperatures to rise quite a bit, with locations south of New England seeing highs into the 40’s. Conditions will likely remain pretty quiet for the end of the work week south of New England as well as zonal flow begins to setup in the mid levels of the atmosphere.
Mid level heights will rise substantially on Saturday morning, leading to a mainly calm and warmer day. Temperatures should be able to reach into the lower to middle 40’s during the day, with some locations south of the city likely getting into the 50’s! These temperatures will be quite a bit above-normal for the middle of winter, so enjoy them while they last!
More dry and warm conditions are expected to hold on for Sunday as a large storm begins to gather over the Rocky Mountains that will likely impact us early next week. Regardless, temperatures should be in the middle to upper 40’s once again, with mainly clear conditions expected, making it another great day to get some things done outside like getting rid of the last of the holiday decorations!
This afternoons NAM model showing a drastic change in mid level temperatures over the East during the next three days
Large Plains Snowstorm and What It Means For Us
A large trough will be digging deep into the Rockies and southern Plains by Sunday night, which will trigger a surface low to develop over portions of Kansas and Nebraska. This system will have rich tropical moisture feeding into it from the Gulf of Mexico and as a result, a very expansive area of precipitation will fan out with the help of an impressive upper level jet. Heavy snow will likely fall over the northern Plains, with heavy rain and some thunderstorms likely across the Ozarks and Gulf Coast. This system will likely then begin to weaken a bit, but the strong moisture feed will continue to pump northward as the low moves east towards the Great Lakes. By this time the entire East coast should be in the warm sector of this system, with temperatures likely reaching into the well-above normal category once again. By Tuesday evening, we could be looking at a large cold front moving through the Northeast with associated heavy rainfall and potentially some embedded thunderstorms. There is strong model support for this system almost a week out, but we will certainly be monitoring it over the next few days, so be sure to check back for more updates!
This afternoon European ensembles showing a pretty impressive signal for heavy rain next week across much of the Northeast
Have a great night!
Steve Copertino