Today has been quite a pleasant way to end the workweek across the entire New York City metro area as highs rose into the middle 50’s to lower 60’s! These mild conditions will be short-lived as we turn our attention to two areas of low pressure that have the potential to bring some wintry weather to the area.
Good Afternoon!
Welcome to December folks! Today was a relatively cool and calm day as another area of high pressure has edged its way into the Northeast after a cold front passed through the region last night and brought some light rain to most locations. This area of high pressure has ushered in some cooler temperatures aloft and at the surface, in addition to some drier air that allow temperatures today to drop to near-normal levels, with most of the Northeast staying in the middle to upper 40’s, with locations closer to the coast getting into the 50’s. Despite the near-normal temperatures, the air did have some bite to it this afternoon as winds gusted up to 20 mph in some locations, which certainly made conditions feel a little cooler than they actually were. Regardless, this was a rather beautiful start to December with mainly clear skies area-wide. With high pressure still in control as we head into the evening hours, conditions will be quite favorable for radiational cooling to take place across the entire northeast. There may be come high clouds from some weak remnant upper level energy passing by, but we expect temperatures to drop into the low 30’s and upper 20’s for the immediate New York suburbs, with middle to lower 20’s possible for locations to the north and west of the area.
A look at the RTMA this evening showing cooling and clear conditions over the entire Northeast. Lows tonight are expected to fall sharply into the 20’s and 30’s across much of the area (Courtesy of Simuawips)
This Weekend
Saturday should start off quite clear and cool in the morning hours, as the area of high pressure begins to move up and out of the Northeast. As the high gradually shifts east during the day, surface winds should begin to respond and shift to a more southerly/southeasterly component. This should allow slightly warmer temperatures to move in tomorrow for the southern portions of New England and the Mid Atlantic states where highs in the upper 40’s to lower 50’s will be possible closer to the coast. Highs in the northern and western locations of the Northeast should stay in the low to middle 40’s as more stubborn cold air holds its ground. Tomorrow looks rather pleasant as the entire nation is stuck in this progressive west to east flow that has dominated the pattern of the past few weeks. A weak shortwave trough will be embedded in this fast west to east flow tomorrow, and should pass over the Northeast by the early afternoon hours. This shortwave trough will be highly sheared and moisture starved, so only some high clouds are expected from this system. Calm and clear conditions will extend into the evening and overnight hours as the aforementioned shortwave rockets off the east coast. With light winds, dry mid levels, and cool mid level temperatures, conditions will once again be supportive of efficient radiational cooling to take place. Expect lows to once again drop down into the low 20’s for locations well removed from the coast, with upper 20’s and lower 30’s as you get closer to the New York City metro area.
Sunday also looks to be another nice and quiet day across much of the Northeast. Previously, there was a chance at some light rain showers from a weak disturbance moving through Canada, but since Wednesday model guidance has been trending weaker and drier with that system, so at best this system may be able to increase clouds throughout the afternoon hours. With the zonal flow still in place and no real airmass change in site, we expect temperatures to remain generally right around average for this time of year, with highs in the lower to upper 40’s across much of the area. some locations closer to the coast may once again be able to nudge into the lower 50’s if sunnier conditions and offshore winds persist. High clouds may last into the evening and overnight hours on Sunday, but this should have relatively little impact on the overall sensible weather. Expect lows to drop into the low to middle 20’s north and west, with upper 20’s to low 30’s likely across the New York Metro area. Overall, this weekend looks to be a quiet one with seasonable temperatures, so if you’re planning to get the holiday decorations up, this weekend would be an excellent time to do so!
This afternoons ECMWF model showing the zonal flow pattern that the CONUS has been stuck in for a while now. The west to east flow does not allow for systems to slow down and strengthen, leading to relatively dry and quiet conditions across s the country
Big Changes In the Pattern Moving Up In Time
We are still on track for a substantial and total change in the overall synoptic pattern across the Northern Hemisphere starting as early as next Wednesday. By this time, a massive area of mid level ridging will balloon over the west coast and up into the Yukon territories of Canada. As this ridge goes up, we’ll also see another area of anomalous riding go up near Greenland. As these features build and establish themselves during the middle of next week, we should see the atmosphere respond in a rather big way. A large storm system should take shape in the central part of the country, and then move north into Canada. Large storm systems that cut up the central part of the country are usually tell-tale signs that change is coming to the pattern. As the low pressure area quickly heads up into Canada, Arctic air will rush down on the western side of the low thanks to the aforementioned area of ridging that will be established over the west coast. This blast of colder air will move quickly behind a strong cold front associated with the decaying low pressure that will move well into the northern portions of Canada by the end of next week. This cold front may have some significant precipitation associated with it as the mid level trough accompanying it is able to dive all the way down into the Gulf of Mexico.
This afternoons EPS showing the difference between the zonal flow we have been stuck in compared to the much more amplified pattern we’re heading into
After the initial cold shot by the end of the week, we should begin to see a near-constant feed of Arctic air into the central and eastern portions of the country, with the possibility of numerous northern stream disturbances diving down from Canada. Since we should have an established block by this period, we may have to watch as these systems will have the chance to slow down, and strengthen close to the east coast. This is an idea that is supported by this afternoons latest model guidance and fits the pattern of years past as well. Regardless, we are going to be moving into a much more winter-like pattern by the end of next week, with the initial setup taking place by the middle of next week. This cold and potentially active pattern should last at least into the middle of December, with the potential for the pattern to reload and strengthen throughout the rest of the month. We will have more updates early next week on this pattern!
This afternoons GFS model showing the initial cutter that kicks off the pattern change and brings in much colder air into the CONUS with a potentially active storm track across the country over the next few weeks
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Have a great night!
Steve Copertino
Good Evening!
The storm that bombarded portions of the Northeast over the past day is quickly moving out over eastern Canada, but the storm certainly left its mark. Most of the Northeast saw heavy rainfall totals in the range of about 2-5″, but the main event from this system were the winds that roared in overnight last night. As the low pressure area rapidly deepened and moved ashore over NJ and eventually progressed into New York state, it carried a large an impressive area of high winds just above the surface over portions of Long Island, Connecticut, Rhode Island, Massachusetts, Vermont, and Maine. As the storm began to fill in with warmer air and weaken, these winds just above the surface were able to rapidly crash down to the ground and cause an impressive amount of tree damage. Hundreds of thousands of folks are still without power in many of the states above, with over 400,000 customers without power in Maine alone. While these winds were rather impressive, the main story west of the immediate area of low pressure were the torrential rains that fell. Deep tropical moisture streamed northward into the Mid Atlantic and Northeast states, and when this moisture was met with the strong dynamics aloft, heavy rain became focused over New Jersey and portions of New York for several hours. Some locations were able to rack up rain totals in the 4-5″ range when all was said and done, with some minor street and river flooding noted. As we stated last week, the reason that these rains were not a bigger story was because an existing minimal drought muted out the overall impacts.
Sunday nights radar near the peak of the coastal storm that brought heavy rains and high winds over the region
As day broke today, a strong westerly jet associated with the backside of the low pressure system was working its way over the Northeast. Due to more mixing of dry air in the atmosphere, this low level jet was able to bring gusts down to the surface in the range of 30-40 mph, which brought some additional tree damage to the region. It also made for a cooler and more classic fall day as cooler Canadian air was briefly tapped. With partly sunny skies and cooler temperatures aloft, highs were able to make it into the middle 50’s across much of the region, but cooler conditions to the north and west kept highs down in the low to upper 40’s-with some stations in New York state even reporting snow showers! As the massive low pressure system continues to pull away this evening, wind have shifted from northwest to southwest as high pressure begins to build in from the south. As the winds shift, the gusty 20-30 mph conditions will begin to die down as the pressure gradient from the two opposing systems weakens with time. Given the clear skies and low humidity, conditions will be marginally supportive for radiational cooling to occur tonight which should knock temperatures down into the upper 30’s and lower 40’s across the area.
High resolution visible satellite imagery and surface observations over the northeast showing cooling and windy conditions
Tuesday and Beyond
The area of high pressure just south of the area will continue to build north throughout the day tomorrow, which will allow for dry conditions and generally clear skies. Highs will likely be limited to the middle to upper 50’s during the day tomorrow despite winds coming from southwest winds at the surface, but cooler Canadian air continues to work in at the lower levels of the atmosphere. Winds will also likely die down completely by tomorrow afternoon, so as we work our way into the evening hours, we should see ideal conditions for radiational cooling to take place over the entire area. Low level temperatures will likely be below freezing already, so expect lows to drop into mid to upper 30’s, with some of the more interior locations possibly even dropping below-freezing and into the upper 20’s. With little to no winds, frost will be increasingly likely the farther away from the coast you move.
By Wednesday some changes will be in the works as a large area of low pressure begins to move towards the Great Lakes region. As this low heads northeast, it will bring a surge of warmer air along a warm front over the area, which should work to bring highs back into the upper 60’s and lower 70’s once again. Given the breadth of this system, we will likely be in between the cold front and warm front until Friday, when the cold front will finally pass, bringing a marginal chance of showers during the afternoon hours. Highs will likely remain in the upper 60’s to lower 70’s through this period, before the cold front knocks temperatures back down to more seasonable levels.
By this weekend temperatures should once again cool down with northwesterly flow returning from Canada, but we may have to watch for a threat of showers once again later in the weekend as a potential wave of low pressure rides north along a stalled cold front over the area. There is still considerable uncertainty with this solution and we’ll have more details by Wednesday as the model guidance converges on a more clear solution.
Snapshot from the 12z ECMWF model showing slightly above normal temperatures during next weekend with the return of higher heights in the east
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Have a great night!
Steve Copertino