A strong Atmospheric wave is emerging from the Tropics. It is expected that it will influence weather patterns in the Pacific Ocean and North America. It could even play an important role in the development of tropical storms early in the month.
Global weather is complex. There are thousands of factors that influence its development at different scales. However, weather is connected globally regardless of where it occurs.
We will be looking at one of these global weather elements, which is now emerging in the tropics as an atmospheric wave. It will be explained to you and how it will affect weather development as the meteorological summer officially begins.
ATMOSPHERIC WAVES
Invisible tropical wave-like features in our atmosphere are responsible for a lot of global variability. The Madden-Julian Oscillation (or simply known as) is the largest and most dominant source for short-term variability in the tropical regions. MJO.
What is an MJO Wave? It is an eastward-moving disturbance that causes thunderstorms, clouds and rain, as well as pressure anomalies. It can travel around the entire planet at the equator in 30-60 days.
It also has the ability to influence weather patterns further north than the North Hemisphere due to the strong connection between the global weather and the tropics.
The MJO is made up of two parts. One is the Wetter rainfall is more commonPhase and the other is Suppressed rainfall (dry) phase. The graphic below, from NOAA Climate, shows two main components to this wave: higher storms and more rainfall (lower pressure), and lower storms and drier conditions (higher pressure). Image by NOAA Weather.
As you can see, the air is converging (moving towards each other) over the wet and the dry phases. This horizontal movement of air can be called the Velocity PotentialIn the tropics.
How can we track an MJO Wave? These larger-scale air movements can be viewed and the areas that are rising and falling.
The graphic below illustrates exactly that. The horizontal movement of air at the upper levels (12-13km), where lower pressure and wetter weather are indicated by cold colors, while warm colors indicate dry weather with fewer clouds or precipitation.
The movement of the wave can be seen as a series of phases. Each has its own influence, so we need track of how it is moving around. This allows us to easily identify the location of each wave and the influence it has on the weather patterns.
During the Atlantic Hurricane Season, monitoring is crucial. This is because the MJO wave’s enhanced/wet phase can provide favorable conditions for tropical system formation over the Atlantic Ocean. It also supports the intensification and growth of tropical systems so it is important to keep track.
Below is a great visualization showing the MJO phases moving across the globe. The animation shows the cloud patterns during wave activity. Blue is associated with more clouds and more rainfall. Brown areas are dryer and have fewer clouds.
To help put things in perspective, we have also produced a video animation displaying the global atmospheric humidity as precipitable waters. We can see how the tropical regions connect with the mid-latitudes, providing “atmospheric rivers” and playing into the global weather system.
A WAVE EMERGING
The latest analysis shows that the convective phase is emerging over the western Pacific Ocean. The Atlantic Ocean is currently experiencing the dry/suppressed phase. This corresponds to phase 6.
We can see a completely different picture if we look ahead a week. The Atlantic Ocean and North/South America are both in the wet/enhanced phases. The dry phase is located over the Indian Ocean, the West Pacific, a combination of phase 7/8.
MJO WEATHER FUTURE
Now we know what the MJO wave looks like and how it moves around the globe. Below is a diagram showing the ECMWF ensemble forecasts for the MJO phases. It is easy to read as we can see which phases it is in and which days.
We are currently in phase 6, then moving into phase 7, and finally into phase 8. Below are the NOAA temperature composites. These represent temperatures across the United States during the warm season. Each phase can show temperature anomalies.
Phase 6 shows a warm tendency in the eastern United States. Phase 7 is cooler in the east, and warmer in the west. However, phase 8 favors negative anomalies more than the eastern United States.
We will now examine the weather forecast for the next two week, looking for MJO signals from the Pacific Ocean and the Atlantic.
GROWING WEATHER EFFECT
Below is the Phase 6 pressure anomaly composite. It covers the Spring season. It suggests a high pressure ridge over the North Pacific, and the eastern United States. We also have a low pressure system over the western United States of America and western Canada. NAO is currently in the negative mode.
These composites are based on historical data from each phase during different seasons. It attempts to find a signal that each MJO Phase produces at a particular time of the years. It is a guideline on how to interpret these waves’ influence.
The pressure anomaly forecast for late May shows the low-pressure region over western Canada and western United States. High pressure is observed over the eastern United States, and there is a ridge in North Pacific. This is in good agreement with the phase 6 signal.
The temperatures are the first to show a strong warm anomaly within the Polar regions. This is not related to the MJO. However, we do have a typical phase 6-type pattern across North America. It ranges from west cold to east anomalies.
This stark contrast can be seen in North America. We see stronger negative anomalies across much of the west United States. In the warm southerly flow, warmer than usual weather is expected in the northeastern United States.
According to the ECMWF phase forecast, phase 7 will play a major role in June.
PHASE 7 WEATHER PACKET
The composite for phase 7 during the May-July period shows high levels of pressure over the United States. Low pressure is bound to North Pacific and likely eastern United States. NAO remains in negative mode.
This is exactly what the ECMWF pressure forecast shows, with a ridge above the United States. A large area of low pressure is found over North Pacific, while an outgoing low-pressure system is located over eastern United States.
The temperature composite shows that the eastern end has negative anomalies and the west has warmer temperatures. However, the actual weather is always changing due to other factors.
The phase 7 MJO pattern is evident in the 850mb temperature anomaly of early June. We now have cold anomalies to the east and warm anomalies to the west, as opposed the previous phase.
Below is a forecast for North America’s surface temperature anomaly. The forecast predicts that colder than usual air will spread into the Midwest and northeastern United States. This pattern is expected to be in the range of the phase 7 influence of MJO wave.
NOAA FORECAST 6-10 DAYS
The weekly forecasts of the United States are also released by NOAA regularly. Below you will find the temperature forecast for the next 6-10 days. They call for colder temperatures in the Midwest, and parts of the northeastern United States. The west and far south will experience warmer weather.
The changes in the tropics are just beginning to be fully understood by the forecasts. We can expect more adjustments over the coming days.
Below is the official precipitation outlook, which predicts more precipitation along the east and west coasts. However, the east half of the United States will see less precipitation due to the cooler northerly air.
INFLUENCE OF THE MID-MONTH WEATHER
The MJO forecast phase chart can be seen again. Phase 8 will be active within the range of 10-15 days. The evolution from this point onwards is uncertain and requires close monitoring. The MJO will likely return less activity and disperse.
Phase 8 of the warm season is a low-pressure zone that occurs in the North Pacific and southern United States. This phase usually sees a high pressure anomaly over Canada.
This forecast is based on the ECMWF ensemble forecast. Canada’s high-pressure remains stable, while the North Pacific is experiencing low-pressure anomalies. Over the United States, we don’t have a clear pattern, but it does trend towards lower pressure anomalies in the northern or eastern part of the country.
The temperature pattern of phase 8 in the summer is typically warmer in western Canada. It is trending cooler in the USA than normal over the northeast and the far east.
The ensemble forecast shows that the northeastern United States has a trend that is cooler than usual. The Western United States is also warmer than average, as is Canada.
NOAA 8-14-DAY WEATHER OUTLOOK
This process is captured in the official NOAA temperature outlook for the 8-14-day timeframe. NOAA forecasts cooler than normal conditions in the northeastern United States, and the pacific Northwest. Warmer weather prevails in the central and south United States.
The changes in the tropics are just beginning to be fully understood by the forecasts. We can therefore expect the NOAA forecast to expand both the normal and the colder areas further into central and northeastern region.
NOAA’s precipitation outlook also predicts wetter weather in the northwestern United States. However, we’ve seen that cooler anomalies can also mean less precipitation for the eastern half.
Officially, the Atlantic Hurricane Season begins on June 1. We will examine the possible impact of this MJO wave on early tropical activity.
MJO WAVE AND TROPICAL EXPECTATION
First, we can see that the forecast predicts a strong wet/enhanced storm over the Caribbean and Atlantic oceans early in June. This pattern is generally supportive of any tropical development. However, we are still in the very early stages of hurricane season so its impact on us is not as great.
The ocean surface temperatures are much higher than normal in the Caribbean and Gulf of Mexico. Tropical development is supported by the ocean temperatures.
Looking at the actual forecast, the ECMWF ensemble indicates that a low-pressure system is developing. The forecast suggests that a system could form in Gulf of Mexico and move towards Florida.
The precipitation anomaly forecast indicates that there will be more rainfall, which suggests that a low-pressure system may develop.
The operational ECMWF forecast indicates a tropical storm in Gulf of Mexico, moving towards Florida in the first weeks of June. These forecasts are subject to rapid change, so we will be closely monitoring the situation.
The overall synoptic environment is favorable for the early development and establishment of tropical systems. It could be a support factor for significant hurricane development if a strong MJO waves appeared in the middle of or late Hurricane Season.
The National Hurricane Center has already issued an area watch, with a 20% chance of a tropical system developing in the next five days. This shows the legitimate potential for the first tropical system to form in the 2022 hurricane season.
As new forecasts and data become available, we will publish regular weekly and monthly updates. Bookmark our page. Also, if you have seen this article in the Google App (Discover) feed, click the like button (♥) there to see more of our ForecastsFind the latest articles from us Weather Nature in general.
SEE ALSO
Atlantic Hurricane Season 2022 will be the 7th straight above average activity. There is a higher chance of major hurricanes hitting the coast of the United States.
Source: Severe Weather
