Spring season 2022 is fast approaching, with forecasts showing that the weakening La Nina will influence the jet stream pattern over North Pacific and Atlantic. A high-pressure system in Pacific will determine the dynamic weather over North America. Meanwhile, Europe is seeing a westerly flow.
When trying to understand any weather season and the forecasts, we must realize that there are many “drivers” that can shape it. Global weather is complex. There are many small and large climate influencers.
Some of these drivers are strong enough to forecast to a fair extent even over a longer range. This can give us an indication of the prevailing weather patterns for a few weeks or months ahead.
We don’t have the ability to see actual temperatures or precipitation between cities. However, we can examine the large-scale pressure system and the position of jet stream over the Northern Hemisphere. Spring 2022 seasonal forecast.
WINTER 2021/2022 SO EARLY
We are now at the end of half of the meteorological Winter season. We will quickly review the evolution of the winter season, including monthly temperature anomalies as well as the pressure patterns that have influenced the winter weather. The meteorological winter season covers the December-January-February period, so we will look at December and half of January so far.
Below is the pressure pattern for December 1st through January 17th. What stands out is the strong semi permanent high-pressure system in North Pacific. We also have a wide low-pressure area that covers western Canada. This includes Alaska and the northwestern United States.
This pattern drives the jet stream to the east and north of the United States. This helps to create and sustain a ridge in the southeastern United States that brings milder/warmer weather.
A ridge is visible over Europe, from the West to the North Atlantic. This means that the east side of the ridge is low-pressure, which brings colder weather to Scandinavia.
Below are the global temperatures for December 2013. There are a lot of cold anomalies north of the 60N latitude in the Polar and subpolar regions. Greenland is an exception, which is located under a high-pressure system.
If we look closer at the United States in December, we can see strong warm anomalies throughout the country. The south-central states have the highest temperatures, with the north border being the coldest. The northwestern United States received cold fronts from the cold air of western Canada.
Europe sees colder conditions in Scandinavia, while the warmer conditions prevail over most of central and west Europe. A notable anomaly in the rest of the globe was the colder than usual conditions over eastern Australia, and the warmer than average conditions over large parts of central and west Europe.
The situation is slightly different for January. The colder temperatures are extending into the northeastern and south-central United States. The jet stream is dropping further over the United States and removing the ridge above the southeast.
The pattern in Europe was different from last month. Warmer than normal weather prevailed over central regions, while normal to colder conditions prevailed over the west.
The pressure pattern forecast for February is below, based on the United States CFSv2 Model.
The main driver of North American weather is a strong high-pressure system in North Pacific. Low-pressure is maintained over Canada as a response. This bends the jet stream to the northwestern United States and then into eastern Canada.
The strong cold pool over Canada is evident in the global temperature forecast. This is due to the presence of a low-pressure area in the region and a northerly stream.
The central and southern United States appear to be much warmer than usual, while the Midwest and northwest will experience cold outbreaks. This weather pattern supports cold outbreaks in the east and central United States, as we’ve seen this winter.
High pressure over the west will bring temperatures higher than usual to Europe. However, it also supports a cooler northwesterly stream into parts of central or southeastern Europe.
GLOBAL OCEANS & SEASONAL WEETHER
La Nina, a tropical Pacific Ocean event, has been one of the main drivers of this cold period.
Below is the latest global ocean temperature anomaly. The tropical Pacific region’s surface water is much colder than normal. This is a mature La Nina phenomenon, which stretches far across equatorial Pacific Ocean. The trade winds are responsible.
The La Nina cold pattern has been a key feature in weather development since Fall and will continue into Spring.
La Nina is simply another name for the cold ocean temperatures of the tropical Pacific ocean. ENSO is actually the ocean-atmosphere system.
ENSO is short for “El Niño Southern Oscillation”. This is a tropical Pacific Ocean region that alternates between warm and cold phases.
The tropical trade winds, which circle the Earth close to the Equator, usually initiate or stop a phase as they mix the ocean surface with the ocean currents.
The image below, taken by NOAA Climate, shows a typical circulation pattern during cold ENSO ocean events. Air descends in eastern Pacific, creating stable, dry weather conditions. Contrarily, air rises to the west Pacific, creating lower pressure, frequent thunderstorms and a lot more rainfall in the west Pacific.
ENSO has a large impact on tropical convection patterns and the ocean-atmosphere network. It spreads its influence worldwide through this delicate system.
Usually, we observe a shift in global pressure patterns with the emergence of ENSO phases. Each phase has a unique impact upon the weather globally.
A particular phase (warm/cold), usually occurs around late summer/early autumn and can last up to next summer or even two years in certain cases.
The cold phase is called La Nina The warm phase is also known as El Nino. Each ENSO phase can be determined by the temperature anomalies in the ENSO3.4 region in tropical Pacific. The image below shows the results.
A high-resolution animation of the development of a cold sea phase is the best way to visualize it.
The video below shows cold ocean anomalies that emerged in the tropical Pacific around the month of July. Notice the “waveforms” across the region, as the surface waters are being pushed west by the trade winds.
Below is a forecast and analysis image from several long-range North American models. It shows the La Nina of last year weakening and a new one emerging during Fall.
The forecast for 2022’s first half shows that the cold phase will be at its coldest in winter. It will slowly diminish in the following months but its influence will still be felt well into spring 2022.
Below you will find the ocean temperature forecasts for the Spring season based on multiple global long-range models. It shows a very weak cold ocean phase in equatorial Pacific Ocean.
It is weakly present in the ocean, but has a strong influence in atmosphere, as we will see below in the forecast.
WEATHER AND JET STREAM
The changing jet stream is often the first sign of the ocean anomalies’ influence. The jet stream is a powerful stream of air (wind), at an altitude of around 8-11km (5-7mi).
It flows in a west-to-eastMotion in the entire Northern Hemisphere affects pressure systems and their strength. This influences our weather on the surface.
Below is an example illustrating the jet stream in winter at 300mb elevation (9km/5.6mi). The jet stream is seen in this example being quite deformed as it descends over the United States. This brings colder air down from north.
It curves upwards above northwestern Europe. This formation brings colder temperatures to the eastern United States, while it is stormy in Iceland and the British Isles.
The strongest effect of a cold ENSO Phase is historically a strong blocking high–pressure system in North Pacific. The image below shows an average pattern for the last few winters that had a cold tropical Pacific Ocean event.
We can see the strong high pressure system in the North Pacific as well as the low-pressure region over Canada and southwestern Europe. It is difficult to determine the ENSO influence in Europe, as the Atlantic plays a significant role.
The strong high pressure system encourages the development a low-pressure area over Alaska and western Canada. It bends the jet stream downwards between the pressure systems. This is exactly the weather pattern we have been seeing this winter.
The image below shows the average position of jet stream during La Nina winters and the resulting weather patterns across the United States and Canada.
The shifting jet stream brings cooler temperatures and storms from the north into the northern and the northwest United States. This creates warmer and drier conditions in the southern and eastern states.
The jet stream can divide the United States into two weather poles. The northern region of the country is more prone to cold and wetter events, because the jet stream directs the storm systems and cold weather there.
This can, however, lock out the southern United States because it creates more stable weather and less frequent storms.
After passing Canada and the United States the polar jetstream moves out into North Atlantic. La Nina may lose its direct influence on Europe here, as the Atlantic region’s weather systems play a large role.
It can still have an important influence on the position of the North Atlantic jet stream. The Atlantic systems can be merged with the jet stream, creating a new weather pattern in Europe.
The problem is that the end result is much more unpredictable than in North America. North America feels a more direct weather influence.
SPRING 2022 – FIRST SEASONAL FORECAST
Now we know what La Nina actually is and how it can affect the jet stream and weather. We will now examine the global long-range models and how they see the Spring 2022 season.
We decided to concentrate on the three main (or most commonly used) seasonal models. The ECMWF from Europe and the UKMO from the United States, respectively. Graphics are from Copernicus Climate EU project, and the CPC/NCEP.
These forecasts provide an average picture of the weather over three meteorological spring months (March, April, and May) and show the prevailing patterns. Even if the forecasts were accurate, it does NOT mean that such weather conditions would last 3 months. It is only an indication of how weather patterns might look 40-60% most of the time.
ECMWF SPRING SEASON EARLY
The ECMWFModel is often referred to most frequently as the most reliable model, at the least in the long-range category. The actual reliability of the model depends on the year/season. However, the ECMWF model is the most reliable.
But no long-range/seasonal forecast can ever be deemed “reliable“We are only looking at trends, and how weather patterns are changing over longer periods of time.
Below is the forecast pressure pattern from ECMWF. It shows the typical La Nina high pressure system in the North Pacific. The Greenland region and western Canada are dominated by the low-pressure area. As we saw in the previous segment of the video, the jet stream is moving between the high-pressure and low pressure systems.
We also see the North Atlantic positively North Atlantic Oscillationmode, which refers to an amplified stream of jets over the British Isles into Scandinavia. This setup is positive NAO, but it is weaker. A positive NAO usually means milder/warmer conditions in Europe and the southeastern United States.
Below is North America’s airmass temperatures forecast. The forecast for Western Canada is to be colder that normal. The jet stream means that there is a high likelihood of colder air moving south to parts of the northern United States. The Southern United States will be warmer than normal.
Europe also has temperatures that are higher than the average. Although a more dominant westerly flow scenario is suggested, the pressure pattern allows for a break in flow. It is possible to have occasional cold flows from the northwest Europe down into the central region.
Europe’s surface temperatures are generally higher than normal when we look closer. The eastern regions are more likely to experience warmer temperature anomalies and milder weather. The northwest may occasionally bring cold fronts to the west, and there will be occasional pattern swings in the central and western regions.
The ECMWF forecasts that Noth America will see colder than normal temperatures shows that much of Alaska and western Canada are colder than usual. There is a sign of colder weather intruding into the Midwest and the northwestern United States. For the southern regions, warmer temperatures than usual are expected.
Despite being warmer than usual, the northeastern and central parts of the United States get snow and colder weather in the early spring due to these jet stream patterns.
Below is the precipitation anomaly forecast. It shows a more typical La Nina type pattern for Canada and the United States. The mainland United States is forecast to have wetter conditions in the northeast and east, and dry conditions in the southwest.
Europe is seeing more precipitation than its northern regions, which are home to most of the low-pressure system. The high-pressure system is forecast to bring western Europe dryer conditions.
UKMO SPRINGSEASON FORECAST
The second choice model is the UKMOmodel, taken directly from the United Kingdom Met-Office. This has also been a good performer in the past years, so we tend to include it in our standard “package” of early model forecasts.
The UKMO has a slightly more complex pattern than the ECMWF. It is what one would expect from this range. It shows that the strong La Nina blocks high-pressure in Pacific. It does have a stronger Canadian low pressure zone and a stronger North Atlantic low-pressure area. This can also be explained by the lower ensemble spread of the model.
This positive NAO pattern is stronger and creates an amplified jet stream to northern Europe and a longer-lasting high-pressure zone above Europe.
However, the temperature forecast is still similar to that of the ECMWF. Over North America, the cold pool extends from western Canada and Alaska to the northwestern United States. The UKMO model predicts that the southern and eastern United States will be warmer then normal.
Europe is experiencing mostly warmer than average conditions with a storm track higher up in northern Europe.
Europe is more focused on the northeastern and central regions of Europe. The UKMO suggests that there is little room for cold air intrusions. We have seen cold air outbreaks every year. Each year, the number of these outbreaks changes.
The double weather pole can be seen over North America. It is colder in the north of Canada and warmer in the south. The exception is in the Midwest and the northwestern United States. They have colder than average temperatures. This is where cold air can also flow down from Canada to the eastern United States.
The precipitation forecast clearly shows the drier conditions in the Southwest United States. The jet stream can bring more rain to the eastern and northern parts of the United States. Europe has higher precipitation than the northern regions due to storms moving more frequently over this area.
CFSv2 SPRING SEASON FORECAST
Contrary to European models, we prefer to use the main North American long range model, the CFS version 2The United States NOAA/NCEP.
CFS model is closer than the ECMWF. It has a strong high-pressure area in the Pacific and a separate low-pressure area over western Canada. This creates a pressure/temperature differential between Canada and the United States. The jet stream then passes over the north United States.
The North Atlantic jet stream bends northeastward over the British Isles, and Scandinavia. This is a typical positive NAO-type pattern with warmer than average weather in Europe.
The North American airmass temperature is most interesting, with a cold anomaly in Western Canada and warmer air in Southern America. Europe is warmer than normal. This is due to storms moving further out in northern Europe, which locks out the colder air.
Europe is showing temperatures that are significantly higher than normal across much of the continent, particularly in the northern regions. This forecast is similar to the two seasonal models mentioned above. It seems to be a consolidated (high reliability) forecast at this point.
Below is the North American forecast. It shows a dipole-type temperature pattern. The northwest United States and western Canada are experiencing colder temperatures than normal.
The southern regions of the United States experience warmer than average weather. The warm anomaly has a gap that indicates a possible path for spring cold to the northeastern United States from the Midwest.
The global precipitation forecast shows that the southwest United States will experience drier conditions than usual. The jet stream moving over these areas will likely bring more precipitation to the Northwestern and eastern United States.
We see drier conditions in Europe’s central, western, and southern regions. The main storm track is in northern Europe and the forecasts for weather conditions are favorable.
SPRING EARLY FORECAST – SUMMARY
We have created a simple summary of the Spring 2022 forecast because sometimes reading descriptions and images can be confusing.
EuropeIt is expected to experience temperatures that are higher than average for most of the continent. However, this does not mean there will be no cold fronts or colder days. This simply means that cold fronts and colder intrusions into the air will be less common in the region.
The North Atlantic pattern is close to the agreement of the models. The main difference is in the strength of the low pressure over Iceland/Greenland. The average image from all three models shows lower pressure in this area, which limits the cold air intrusions into Europe.
Over northern Europe, expect normal to wetter weather. As the jet stream moves over these areas, it could bring with it more stormy weather. Mainland Europe will experience a normal to drier spring with drier trends towards the west.
North America spring forecastLooks solid enough to be a typical extension of winter. The majority of Canada’s western and central regions can expect to see snowier and colder conditions than Alaska.
The Northern United States will experience a normal-to-cold spring winter with more precipitation. This increases the probability of spring snowfall events. This is more common in the Midwest and the northwestern regions, but less in the northeastern United States.
The Southern United States is likely to experience warmer and more dry than normal spring weather. This does not mean that no cold fronts can reach the south. This simply means that it is less likely to receive frequent cold fronts to the south in a La Nina-type pattern.
The main channel for spring cold air outbreaks seems primarily to be from the Midwest and northwestern United States. It then flows into the central and east United States. Similar to what we have seen so far this winter.
Below is the NOAA official Spring temperature forecast for the United States. It shows the temperature probabilities, with lower to equal chances in northern United States. The models above show that the probability of warmer than average weather in the northeast and the southern half of the United States is higher than the likelihood of normal weather.
The official precipitation forecast also matches the model forecast. We see an equal-to higher probability of more precipitation for the easter and northwestern United States. The southwest will see a drier spring season than usual in the south.
The main problem with rainfall in any La Nina season is the persistence of drought conditions to the south and west. Below is the latest drought graphic from NOAA. It shows the current drought conditions within the United States.
Most of the western United States are in drought conditions. The south-central and northwestern United States are the areas with the driest conditions. The severe drought conditions are not affecting the majority of the country’s eastern halves.
Spring usually means warmer temperatures returning. However, with warmer temperatures comes severe weather season. This article will conclude with a look at the historical severe weather patterns during a La Nina Spring.
We will include a more in-depth look at severe weather seasons when more forecast data becomes available in the forecast update next months.
2022 USA SEVERE WEATHER SEASON
History has shown that La Nina can also have a significant impact on the Spring tornado season of the United States. And it’s usually not a good thing.
Below is an interesting image from NOAA climate. It shows how frequent hailstorms and tornadoes occur in the spring season of the United States between El Nino-La Nina years.
It is interesting to note that there is a significantly higher frequency of tornadoes and hailstorms in La Nina spring seasons. The United States’ southern and southeastern regions have the highest hailstorm and tornado frequency.
This clearly outlines Tornado Alley. This is a nickname for an area in central America that experiences severe weather events every year.
Why are there more severe weather events and tornadoes in southern United States during La Nina?
This is due to the weather pattern that we saw earlier during a typical La Nina, which promoted a high-pressure system within the North Pacific. This is usually due to the pressure drop in the northwestern United States and western Canada.
This can act as a source area for frequent coldfronts, which move south from the United States to west Canada. The Gulf of Mexico is where the cold front meets the warm, moist air.
The shifted jet stream creates a highly volatile combination with lots of thermal and wind power, which can cause storms to become severe.
The image below shows the April-May–June pressure forecast by ECCC. The lower pressure can be seen over western Canada and extending into the northwestern United States. This keeps the cold pool in western Canada afloat, which fuels frequent cold fronts during spring.
Below is a graph showing the annual tornado counts in the United States between 1954 and 2014. We can see that of the top 5 most active years for tornadoes, 4 were La Nina.
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Source: Severe Weather
