What role did Wisconsin play in establishing the National Weather Service?

Posted on November 6, 2023 by WeatherGuys Editor
Portrait of Increase Lapham (Photo credit: Wisconsin Historical Society archives)

Wednesday was the 153rd anniversary of the first day of operation of what has become the National Weather Service. On Nov. 1, 1870, the first organized set of observations around the country were taken under the auspices of the Army Signal Service.

On Feb. 9 of that same year, President Ulysses S. Grant, fresh from his own experiences during the Civil War, enthusiastically signed the service into existence. Its purpose was “to provide for taking meteorological observations at the military stations in the interior of the continent and at other points in the States and Territories … and for giving notice on the northern (Great) Lakes and on the seacoast by magnetic telegraph and marine signals, of the approach and force of storms.”

Within a week of its first day of operation, the first official weather forecast from a United States government agency was made by Professor Increase Lapham, through the Chicago office. It was a successful forecast of strong winds and significant waves on the Great Lakes, and its issuance may well have saved lives and property, exactly as intended.

Lapham, of course, was perhaps the most famous professor during the early years of the University of Wisconsin-Madison. It was he, in fact, who petitioned U.S. Rep. Halbert Paine, of Milwaukee, himself a Civil War veteran, in the immediate post-war era regarding establishment of a national weather service.

Thus, Wisconsin, and in particular UW-Madison, played a prominent role in the establishment of our National Weather Service.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

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Are hurricanes intensifying more quickly?

Posted on October 31, 2023 by WeatherGuys Editor

Hurricane intensities are classified using the Saffir–Simpson scale, which rates hurricanes on a scale of 1 to 5 based on the damage their winds would cause upon landfall. Major hurricanes are those classified as Category 3 and higher on this scale.

Category 3 hurricanes have one minute of sustained winds between 111 mph and 130 mph. The one-minute sustained winds in a Category 5 hurricane are greater than 155 mph.

Forecasting hurricane intensity is a difficult task, and forecasting how rapidly they might intensify is particularly difficult. Rapid intensification is when a tropical cyclone strengthens dramatically in a short period of time. The National Hurricane Center (NHC) defines rapid intensification as an increase in the maximum sustained winds of a tropical cyclone by at least 35 mph in a 24-hour period.

Intensification of a hurricane requires the right environmental conditions. One is water temperature. If water in the ocean beneath the hurricane is warm enough, it releases large amounts of energy as it evaporates, creating a dip in air pressure that generates powerful winds.

Otis, a storm that struck the southern coast of Mexico, was initially forecast to be a weak tropical storm (one-minute maximum sustained winds between 39 and 73 mph) at peak intensity. Instead, Otis underwent rapid intensification, reaching peak winds of 165 mph when it made landfall near Acapulco, Mexico, at 1:25 a.m. Wednesday. Otis strengthened from a tropical storm to a Category 5 hurricane in only 12 hours. This rapid intensification occurred over a patch of ocean with sea surface temperatures approaching 88 degrees. It came ashore as the strongest storm on record to hit Mexico’s Pacific coast.

Hurricane Otis prior to landfall. Click for an animation. Credit: CIMSS

While forecasts of intensification have improved, challenges remain. A recent paper in Nature found that rapidly intensifying storms that are within 240 miles of coastlines are now significantly more common than they were 40 years ago.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison Department of Atmospheric and Oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: Meteorology, Phenomena, Tropical

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What is the status of sea ice this year?

Posted on October 23, 2023 by WeatherGuys Editor

The surface waters of our polar oceans freeze seasonally, forming a layer of sea ice that varies in thickness from centimeters to meters. The era of polar orbiting satellites has enabled the monitoring of sea ice distribution for more than four decades.

Seasons are reversed between the Northern and Southern hemispheres, so the sea ice maximum and minimum occur at different times of the year. Generally speaking, around mid-September the extent of the sea ice at the south pole is reaching a maximum, while in the Arctic it is approaching a minimum in September as our Northern Hemisphere summer comes to an end.

Arctic sea ice extent for September 19 2023, was 4.23 million square kilometers (1.63 million square miles). The orange line shows the 1981 to 2010 average extent for that day.  (Image Credit: National Snow and Ice Data Center)

This year, the sea ice amount around Antarctica has fallen to a record low. Satellite observations indicate the sea ice extent around Antarctica peaked on Sept. 10. At that time, sea ice covered 6.55 million square miles, which is the lowest winter maximum since satellite records began in 1979. That’s about 386,000 square miles less ice than the previous winter low, set in 1986. The extent of the summer’s Antarctic sea ice also hit a record low in February, breaking the previous mark, set in 2022.

Arctic sea ice reached its minimum extent for this year on Sept. 19, covering 1.63 million square miles. This 2023 minimum extent is the sixth-lowest in the nearly 45-year satellite record. For reference, the combined surface area of the Great Lakes is 94,250 square miles.

The satellite data show a trend in sea ice extent over the Arctic that is decreasing annually at a rate of 4%, plus or minus 1%, per decade. The reduction of Arctic sea ice is rapid, as the northern polar region is warming four times faster than the global average. Over the Southern Hemisphere, satellite data shows no significant trend in sea ice extent. The climate change associated with global warming contributes to melt glaciers in Antarctica, which impacts sea ice extent around the continent.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: History, Seasons

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Is there a typical season for waterspouts?

Posted on October 16, 2023 by WeatherGuys Editor

A waterspout is a whirlwind that forms beneath a cumulus cloud over water. Before you see the waterspout, you may see a funnel-like cloud hanging from the cloud base. The Florida Keys, Gulf of Mexico, and Chesapeake Bay are common regions for waterspouts.

The Great Lakes also have waterspouts, though seasonally. August and September are the most common months for Great Lakes waterspouts to develop, with the full season considered to run from the end of July into October.

Life cycle of fair weather waterspouts (Image credit: NOAA/NWS Sullivan)

There are two types of waterspouts: fair weather waterspouts and tornadic waterspouts associated with severe thunderstorms. The fair weather variety of waterspout is more common than the tornadic and is the most common over the Great Lakes. A fair-weather waterspout is a whirlwind that forms beneath a cumulus cloud and over water and is generally not associated with thunderstorms. A fair weather waterspout develops on the surface of the water and moves upward.

Lake Michigan Waterspout offshore Racine, Wisconsin. Credit: Phil Moeller

Fair weather waterspouts form when cold air moves across warm water. They form when a large temperature difference between the warm water and the overriding cold air exists. Fair weather waterspouts develop in light wind conditions, so they tend to stay in one place or move slowly. They typically have weak circulations and winds, although the bigger spouts can produce wind gusts that can exceed 50 mph and can flip a small boat or damage a dock if they come ashore. Fortunately, these types of waterspouts move relatively slowly and are most often visible from a great distance over the flat expanse of lake waters, so there is ample time to get out of their way.

The International Centre for Waterspout Research is an international organization that monitors and studies waterspouts from all over the globe.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

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Atmospheric and Oceanic Sciences turns 75

Posted on October 9, 2023 by WeatherGuys Editor
The rooftop of the UW–Madison Atmospheric, Oceanic and Space Sciences building. (Photo credit; UW-Madison)

On Friday, the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison celebrated its 75th anniversary.

When the department was founded in June 1948, the modern science of meteorology was arguably just a few years old, and even basic understanding of the nature of the mid-latitude cyclones that batter us from October to May was truly in its infant stages.

The scholarship within our department over this three-quarters of a century has made enormous contributions to our science and, in turn, to the protection of lives and property through improved forecasts of both tropical and mid-latitude cyclones.

Some of the highlights include the launching of the first weather satellites in the late 1950s and early 1960s. These tools now contribute a huge amount of data to global weather forecasting models, and the UW-Madison remains at the very forefront of the research efforts dedicated to remotely sensing the atmosphere and oceans of Earth.

Developments in the computer models that make such forecasts also has a strong Wisconsin pedigree. The recently retired director of the National Weather Service got all three of his degrees from UW-Madison. The Space Science and Engineering Center, or SSEC, originally developed as an outgrowth of the department, has been at the heart of improved forecasts of tropical weather systems, fire detection and severe storms research for decades.

Clearer understanding of both tropical and extra-tropical weather systems, the global oceans and their interactions with sea ice, the complex climate system and many other important, fundamental issues in the atmospheric and oceanic sciences are being generated every day in our dynamic and diverse department. We are grateful to the citizens of the state of Wisconsin for their support of our endeavors, and those of all of our colleagues at our great University of Wisconsin-Madison.

On, Wisconsin!

Steve Ackerman and Jonathan Martin, professors in the UWMadison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at stevea@ssec. wisc.edu or jemarti1@wisc.edu.

Category: History, Meteorology

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