When Does in Nyc Become Warm Again
The Winter of 2021-2022 is likely to brainstorm with a colder and more than wintry pattern than normal in NYC. The second half of the winter, however, is expected to exist warmer and less snowy than normal. NYC's xxx year average annual snowfall is 28.ix″, and nosotros expect slightly higher up normal snowfall this season.
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We say it every year, simply it is worth repeating: Seasonal weather condition forecasting is one of the most challenging aspects of meteorology. It is the production of several months of intensive research, which often begins in the prior Jump. We have been piecing together ideas for this upcoming winter since and so, and we are excited to finally have a finished production.
Instead of focusing on private numerical indexes and values, we are going to endeavor to paint a picture of the atmosphere and what it'll be doing over the side by side few months based on several global and hemispheric oscillations, weather condition, and phenomena. This volition atomic number 82 us to conclusions which we believe will be the guiding forces for u.s. during the seasons ahead.
The role of ENSO
Anticipated ENSO Conditions: Moderate or strong La Nina
The El Niñdo-Southern Oscillation (ENSO) is "an irregular periodic variation in winds and ocean surface temperatures over the tropical eastern Pacific Ocean." ENSO weather condition are 1 of they key drivers to the Wintertime pattern, and can often be broadly referenced as "tropical forcing". Tropical forcing more specifically refers to concentrated areas of showers and thunderstorms, otherwise referred to equally convection, in meteorological regions of the tropics. This convection, nigh frequently observed in warm and moist climates, releases latent heat that and then rises up into the atmosphere, forming ridges of college atmospheric air pressure.
The equatorial waters of the Pacific ocean that comprise the ENSO regions brood a peachy bargain of thunderstorm action, which then accordingly results in atmospheric ridging and later moves downstream. This balances the atmospheric regime. In a general sense, the more dissonant the positive body of water surface temperatures, the more convection that can so exert a stronger forcing mechanism on the adjacent regions of the atmosphere, reverberating throughout the globe.
Almost all forecast model guidance now agrees that we will experience weak La Nina conditions during the upcoming winter. La Nina conditions are observed when colder than normal temperature anomalies exist in the aforementioned tropical regions of the Pacific Sea.
La Nina events tin exist broken downward into subcategories split up from their force, based on location. The most frequently observed types of La Ninas are "central based", when the coldest anomalies are in the central Tropical Pacific and "east based", when the coldest anomalies lean due east, closer to Primal and South America in the eastern tropical Pacific. This year, colder than normal sea surface temperatures extend across both the Cardinal and Eastern ENSO regions, with a slight lean towards the eastern regions closer to South America.
Using a weighted analog set featuring a lean towards eastern-based La Nina events of at least moderate forcefulness, we are able to compile an analog gear up of the SST anomalies in the Tropical Pacific. This analog set up matches quite closely with ongoing and expected conditions.
This analog ready is of import. It helps the states to sympathize where we are heading during the winter ahead and how global circulation patterns may behave. Having confidence in the orientation of SST anomalies in the Tropical Pacific is a central function of the winter forecast and serves as a foundational slice of the forecast as a whole.
The Quasi-Biennial Oscillation (QBO)
Prediction: Easterly descending QBO
The QBO is a very important atmospheric index which monitors the quasi periodic oscillation between the equatorial zonal current of air – from easterlies to westerlies. A negative (easterly) QBO ofttimes supports higher latitude blocking and ridging, while a more positive (westerly) QBO supports some resistance to loftier breadth blocking in those areas.
Recently, an easterly QBO has been observed. This is an important factor in the Winter ahead, especially given the understanding that La Nina events tend to feature Southeast US ridging overall. Recall of information technology this way – if ridging is favored by tropical forcing, this propensity for high latitude blocking to develop could deed to mitigate information technology.
With an easterly QBO in identify, at that place is a greater likelihood of loftier latitude blocking – and we will have to closely monitor the stratospheric polar vortex to see how the higher latitudes might bear.
The N Atlantic Oscillation (NAO)
Prediction: Neutral to Negative (-) NAO on average
The N Atlantic Oscillation (NAO) is an index based on the surface sea-level force per unit area difference between the Subtropical (Azores) High and the Subpolar Low. The positive phase of the NAO reflects below-normal heights and pressure across the high latitudes of the North Atlantic and to a higher place-normal heights and pressure over the central North Atlantic, the eastern Us and western Europe. The negative phase reflects an opposite pattern of height and pressure anomalies over these regions.
A negative NAO is associated with colder, more active conditions in NYC during the wintertime months. A positive NAO is correlated with warmer weather overall. This yr, we are expecting the NAO to average nigh neutral, but negative during the first half of the winter and more positive during the second one-half of the winter.
Other Factors & Analog Years
Analog years are an of import component of wintertime forecast development. Looking dorsum to past years that featured similar atmospheric progressions and weather condition can offer the states a peek into how things may evolve in the winter ahead. We tin appropriately weight these based on our agreement of the atmosphere during those years and how it compares to electric current conditions.
The importance of analogs in a Winter Forecast has been long debated and discussed. How much should a forecaster weigh what happened in the past confronting what is happening currently? How can we utilize past events when the atmosphere is almost certain to behave differently each time, especially given the difference in global weather when compared with weather events from the 1950'southward and 1960'southward?
For the states, each winter is dissimilar. This yr in particular, the number of analog years that fit the prepare of conditions and the overall progression of the atmosphere is very slim. There are simply very few years that featured a variable La Nina land with moderate to strong intensity andbesides fit the design across the rest of the globe.
With that in listen, we decided to weight the analog years in our forecast very carefully, taking but the stronger year(s) and blending quickly down toward the weaker analogs. We're comfortable with our analog composites that were presented and have factored them into our forecast every bit we typically do. Recollect of them as a piece of a much larger forecast puzzle.
When we take the individual pieces of research and compile them into one organized forecast, we can begin to see the ebbs and flows of the winter ahead, as they should be, according to our very best analogs and subset of current and past conditions. This winter, we are confident in our month-to-calendar month composites and take indicated moderate to high confidence on each month.
Beneath, nosotros pause downwardly each month'due south temperature and anticipated precipitation trends. While atmospheric precipitation maps aren't included (lower confidence), we do discuss atmospheric precipitation patterns and potential within each individual calendar month'due south breakdown. Please keep in listen that this forecast is focused on NYC, but national trends are discussed as well.
December 2021
The calendar month of Dec is once once more expected to offering the most wintry intrigue of the season in the Northeast United States. High breadth blocking appears likely to develop equally a result of a weaker than normal stratospheric polar vortex and easterly QBO.
In uncomplicated terms, nosotros wait colder air which ordinarily resides in the Arctic and Canada to exist dislodged southward into parts of the United States. The core of this should remain over the Keen Lakes, but colder than normal temperatures can also be expected across the Northeast.
The potential for wintry weather should be especially during the first one-half of the month. This may initially begin the interior and college elevations, merely the potential for early season snow is also predictable in the NYC Metro.
January 2022
January is expected to be a month that is largely defined by volatility. While the first one-half of the month could be colder and remain active, a mid month transition is predictable. Loftier latitude blocking is expected to oscillate, leading to periods of warmth followed by shots of cold, but no real sustainability to thee pattern. A larger mid month storm could signal a change to the pattern overall.
The 2d half of the month is expected to trend warmer across the Southern and Eastern parts of the country, with that warmth eventually working into the NYC Metro Area besides.
Feb 2022
It is relatively rare to have relative agreement among a series of analogs. While all of our analogs characteristic slightly unlike hemispheric conditions, at that place is one thing that they all agree upon: A Southeast Ridge volition expand in February.
High latitude blocking is expected to retreat during this time menstruation, with a positive NAO and amplified Pacific patter. This will help facilitate troughing in Western North America, and upshot in ridging in the Eastern US. Warmer than normal temperatures are likely in the Eastern U.s.a. as a result.
While February has been active during the past few winters, nosotros expect this one to be relatively quiet in regards to wintry weather condition. Warmer than normal temperatures are expected in NYC as well.
NYC Winter Forecast 2021-2022 Highlights
Temperatures: Slightly warmer than normal (0 to +2)
Precipitation:Wetter than normal
Snow: Slightly above normal (27-33″)
Winter 2021-2022 is expected to be off to a fast kickoff, with colder than normal and more wintry than normal atmospheric condition in the NYC Metro during Dec. Afterward a transitional month in January, warmer and less wintry than normal weather condition are anticipated in February. While temperatures will boilerplate slightly above normal, we do anticipate snowfall to average slightly higher up normal as well.
We wanted to take the fourth dimension to thank yous for reading our Winter Forecast. It is not lost on u.s. how special it is that so many folks take the time to read what we accept to say. Each year, we are fortunate enough to produce and release a Winter Forecast both to clientele and to the public. We are grateful for the opportunity to share our forecast with every bit many people every bit we tin can, and we hope to have delivered a forecast that provides detail, information and clarity.
The forecast was compiled at Empire Atmospheric condition, LLC and New York Metro Conditions, LLC in Fanwood, New Jersey from May of 2021 through November of 2021. The graphics were compiled by John Homenuk. Analog work and composition was completed by John Homenuk, Ed Vallee, Doug Simonian and Steve Copertino.
Cheers to a wonderful Winter ahead!
Source: https://www.nymetroweather.com/2021/11/05/nycwinterforecast2021/