UAMS Blog: 2019
What's been happening in our weather world.
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4/3/19: something cool
4/3/19: something cool
A nor'easter rapidly intensified over the Atlantic last night and currently looks spectacular. I made some animations of the storm to start your day. Enjoy!
Shout-out to Satellite Liaison Blog (https://satelliteliaisonblog.com/). The people who run it are NOAA & NASA scientists and NWS forecasters, and so they know much more than I do about the GOES satellites and storm prediction. If you're interested in weather forecasting, I really recommend their page since it highlights how meteorology from different satellite perspectives.
-Jimmy
20190931236_GOES16-ABI-eus-GEOCOLOR-1000x1000_1.avi3/23/19: Happy World Meteorological Day!
3/23/19: Happy World Meteorological Day!
Formed on this day in 1950, the World Meteorological Organization (WMO) is an intergovernmental agency now a part of the United Nations and is the leading scientific voice for international cooperation on any matters related to climate, weather, and their related impacts.
This year's theme is The Sun, the Earth, and the Weather: "The Sun delivers the energy that powers all life on Earth. It drives the weather, ocean currents and the hydrological cycle.
It shapes our mood and our daily activities. It is the inspiration for music, photography and art." The WMO held a competition for photos of the sun and its related phenomena - you can view the winners here: https://worldmetday.wmo.int/en/2019-photo-calendar-competition.
To celebrate, get out and enjoy some sun today! In Miami, we're extremely fortunate that we can do this all year round. For example, you could take a walk around campus while listening to MIT's new podcast called TILclimate ("Today I Learned: Climate") at https://climate.mit.edu/users/tilclimate-podcast. They're really interesting and accessible ~10-minute interviews featuring leading climate professors at MIT on niche parts of climate change. So far, they did pieces on how planes impact the global temperature, and how chemical particles affect clouds.
-Jimmy
3/20/19: Cyclone Idai, US "bomb" cyclone, looking back on March 2018 nor'easters
3/20/19: Cyclone Idai, US "bomb" cyclone, looking back on March 2018 nor'easters
Cyclone Idai strikes the southeastern African nations of Mozambique and Zimbabwe and may be the worst ever tropical cyclone to affect the Southern Hemisphere.
Cyclone Idai strikes the southeastern African nations of Mozambique and Zimbabwe and may be the worst ever tropical cyclone to affect the Southern Hemisphere.
Rain and storm surge caused catastrophic inland flooding and mudslides, displacing hundreds of thousands of people and killing over 400. The full extent of the impacts is not known, and the President of Mozambique said that it could be as large as 1,000.
The port city of Beira, which has a population of around half a million people, was reported 90% destroyed by flooding, according to the International Federation of Red Cross and Red Crescent Societies (IFRC), which has called it the "worst humanitarian crisis in Mozambique’s history." Various organizations including the United Nations and Doctors Without Borders are on the ground but are cannot provide relief to many affected areas due to flooding.
Our Severe Weather Outreach Day in April will include a fundraiser to the IFRC.
Last week: A "bomb" cyclone creates blizzard conditions in the central United States.
Last week: A "bomb" cyclone creates blizzard conditions in the central United States.
Hurricane-force winds were experienced in Colorado, where all-time low pressure records were broken. Low-pressure records were also broken in Kansas and New Mexico.
Warm weather that followed the storm produced rainfall and melting snow, currently causing massive floods along the Missouri River and in the Midwest. UM's Vanessa Alonso is reporting on this, so follow her on Facebook or Twitter for real time updates.
What are bomb cyclones and are they a recent phenomena or just media hype?
The word "bomb" is used to describe a type of mid-latitude or nor'easter, which are different systems from hurricanes.
Explosive cyclogenesis or bombogenesis technically doesn't have anything to do with how strong a storm ultimate becomes, but instead how fast it develops - it occurs when air pressure decreases on average by 1 hPa per hour over 24 hours at 60°N.
In other words, bombogenesis is simply the most extreme case of the formation of nor’easters, like rapid intensification in hurricanes.
What are they key ingredients to form nor'easters or bomb cyclones?
Compared to hurricanes, nor'easters form off strong horizontal temperature differences. This usually occurs when a cold continental/polar air mass collides with a warm ocean air mass.
The strongest nor'easters therefore typically occur during October-March, when the land-ocean temperature differences are biggest. It's also therefore pretty unusual for one to develop over the Rockies like last week's storm.
There also needs to be divergence, the spreading apart of air, in the jet stream in the upper atmosphere. This occurs in areas along the jet stream known as jet streaks where winds are being concentrated in a smaller area and accelerating.
When air moves apart at the top of the atmosphere, lower level air must rise to replace it. This gives us the unstable rising motion needed for severe weather and the dropping air pressure at the surface.
Air at the surface rushes to the low pressure, and the Coriolis force creates a cyclone! The more the pressure falls, the more intense the cyclone.
The January 2018 blizzard shown below, which was called a bomb cyclone by almost every American news outlet, sparked the popular buzzword we have today. However, scientists have been using "bomb" to describe storms since the mid 20th century.
A year ago: Four nor'easters in three weeks impact the US eastern seaboard.
A year ago: Four nor'easters in three weeks impact the US eastern seaboard.
Notice how all the storms are comma-shaped with a cold front tail. Check out a 1080p time lapse of these storms from March 2018, courtesy NOAA Satellites, below.
-Jimmy
2/24/19: Tropical and extratropical: what's the difference?
2/24/19: Tropical and extratropical: what's the difference?
The Pacific Ocean is vorticity city! Typhoon Wutip threatened Guam earlier this weekend as the strongest February typhoon on record which peaked 24 hours ago at 155 mph sustained winds!
Farther north is a quintessential extratropical cyclone, often called mid-latitude cyclones. Both are intense low pressure systems, but are dynamically very different and form under much different circumstances. The below NOAA graphic will explain some of those disparities.
-Jimmy
2/5/19: Double cyclones spinning off the US east coast
2/5/19: Double cyclones spinning off the US east coast
A strong extratropical cyclone from yesterday has degenerated this morning, leaving behind two smaller vortices in its wake. They are likely too weak to have any noticeable Fujiwhara effect (when two vortices orbit each other), but it is still something you don't see very often!
-Jimmy
What the storm looked like 24 hours prior.
1/30/19: Extreme cold temperatures in the Midwest
1/30/19: Extreme cold temperatures in the Midwest
It might have been colder than usual this week in Florida, but at least we're not in the Midwest! In Chicago, the air temperature is -15F, which is about an 80F difference from the temperature here. This is excluding the wind chill, which is as low as -50F (and even lower in states like WI and MN)! This morning, steam was literally rising off of Lake Michigan:
You might hear a lot about the "polar vortex" causing this extreme cold, a common weather buzzword. Like all weather jargon, it is often misleading. The folks at the Capital Weather Gang at the Washington Post explain the phenomenon better than I ever could:
-Jimmy
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