The Weather Guys

Was the Blizzard of 2016 forecasted well in advance?

Posted on January 27, 2016 by WeatherGuys Editor

A wide corridor of snow can be seen in this stunning nighttime view of the U.S. east coast in the wake of the winter storm from Suomi NPP VIIRS Day/Night Band at 0647 UTC, 24 Jan 2016, courtesy of CIMSS/SSEC at UW-Madison

The blizzard that affected over 80 million Americans from the Deep South to New England over the weekend was a historic storm in many ways.

Perhaps most obviously, the snowfall totals that it delivered in the so-called Megalopolis (the stretch of cities from Washington, D.C., northeast to Boston) equaled or surpassed records in many locations.

Final snowstorm totals varied across major cities on the East Coast, the National Weather Service reported, from 22.4 inches at Philadelphia International Airport, to 27.9 inches at LaGuardia International Airport and a staggering 36 inches in Maugansville, Maryland.

Other locations that don’t often see large snowfall totals — such as eastern Kentucky, which received more than 15 inches of snow — were also hammered by this storm. Additionally, Weather Storm Jonas was the largest snowstorm on record for Harrisburg, Pennsylvania and Baltimore, Maryland and at JFK Airport in New York City.

The fact that the storm was so accurately predicted many days in advance is also noteworthy. Though not the first such accurate forecast in history, it is a high-profile example of the quiet revolution in weather forecasting that has taken place over the last 30 or so years.

The combination of increased observing capabilities (much of that increase in the form of satellite data), increased understanding of the physical processes that produce the weather, and increased computing power has greatly improved the weather prediction enterprise that now informs so much of our decision making in advance of, and in the face of, such extreme weather emergencies.

Such forecasts are the fruits of sustained commitment and investment in basic research in satellite meteorology (of which UW-Madison is both the originator and the world leader), dynamic meteorology and computer technology provided by research grants over decades.

Category: Meteorology, Severe Weather, Weather Dangers

Comments Off

Are hurricanes in January typical occurrences?

Posted on January 19, 2016 by WeatherGuys Editor

This photo, taken from video provided by NASA on Friday, shows Hurricane Alex seen from the International Space Station. The rare January hurricane in the Atlantic closed in on the Azores on Friday with authorities in the Portuguese islands warning of waves up to 60 feet high, wind gusts up to 100 mph and torrential rain.

While rare, there have been other hurricanes in the month of January. This is the fourth storm since record keeping started in 1851. Before Alex, the most recent January hurricane, Alice, was in 1955. Another unique aspect of Alice was that it formed on Dec. 30, 1954 and lasted until Jan. 6, 1955.

Why are January hurricanes rare?

Hurricanes form over warm waters. The evaporation of the warm ocean waters condenses to form clouds and precipitation releasing latent heat energy that helps to maintain the storm. A general rule of thumb is that hurricanes will not form unless the water temperature is at least 80 degrees.

Evaporation is a function of the temperature difference between the air and water. The larger the temperature difference the greater the evaporation. The Northern Atlantic Ocean is typically not that warm in January.

Alex formed over waters whose temperatures were about 68 degrees, certainly below our rule of thumb. But, about 6 miles above, the air was very cold, at minus 76. The 144-degree difference between the air and water temperature, along with small vertical wind shear, helped the storm to develop into a hurricane.

Unfortunately, this early storm does not allow us to make a forecast about the upcoming season.

Category: Meteorology, Phenomena, Severe Weather

Comments Off

What’s really going on in that slush puddle?

Posted on January 11, 2016 by WeatherGuys Editor

Though a slush puddle may look like a static, unchanging, boring and ugly mixture of dirty ice and water, it is actually an extremely dynamic cauldron of various phases of the magical water substance, constantly undergoing all manner of phase changes. Photo credit: Steve Apps, State Journal archives.

The recent snow and ice followed by a bit of melting filled sidewalks and some city streets with puddles of slush — that wondrous winter concoction of liquid water and ice.

Though it is not possible to see, surrounding any puddle of slush is also a cloud of countless invisible water vapor molecules. In fact, of all the many chemical constituents of the Earth’s atmosphere, only the water substance can naturally occur in all three of its phases – solid, liquid and gas – at Earth temperatures.

And, to add an even greater level of grandeur to this fact, the ice and the liquid water in the slush puddle are constantly subject to sublimation (transitioning from ice to vapor) and evaporation, respectively, while the invisible vapor is constantly liable to deposition (transitioning from vapor to ice with no intermediate liquid stage) and condensation.

So even though the slush puddle looks as if it is a static, unchanging, boring and ugly mixture of dirty ice and water, it is actually an extremely dynamic cauldron of various phases of the magical water substance, constantly undergoing all manner of phases.

These phase changes involve substantial amounts of energy transfer as well. In fact, for a gram of liquid water to evaporate to vapor, 600 calories of energy are required from the environment. When a gram of water vapor condenses, that same amount of energy is given back to the environment.

A scientist’s view of the world need be no less lyrical than a poet’s — we hope you will never see slush puddles the same again.

Category: Meteorology, Seasons

Comments Off

What improvements in weather forecasting can we expect in 2016?

Posted on January 4, 2016 by WeatherGuys Editor

There are three fundamental ways to improve weather forecasting: better observations of the atmosphere, improvements in computer models and a better physical understanding of the atmosphere.

The fall of 2016 will see the launch of the next generation of U.S. weather satellites. These satellites, referred to as the GOES-R series, will view Earth with 16 wavelengths, compared to the five wavelengths of the current satellite.

The satellite data will track and monitor cloud formation, atmospheric motion, development of convection, land surface temperature, ocean dynamics, atmospheric water vapor, volcanic ash plume, aerosols and air quality, and vegetative health.

It will continuously take images of the Western Hemisphere every 5 minutes.

It also has an alternative mode of observing where it can make a hemispheric image every 15 minutes along with an image of the continental U.S. every 5 minutes, and smaller, more detailed images of areas where storm activity is present, as often as every 30 seconds.

The National Weather Service’s primary computer was upgraded in 2015, increasing its previous computing capability by nearly a factor of 10.

This has enabled the weather forecast models to reduce the spatial and temporal resolutions, which lead to better predictions.

The improved computer power should also help with using the new satellite observations in initializing the computer model runs with better current weather data.

Improved physical understanding of the atmosphere comes about through research.

Current research directed at challenging problems includes seasonal predictions, tornado development, severe weather warnings and hurricane intensification.

We can expect to see improvements in these topics as well as how the atmosphere and ground exchange energy and the complicated details of how precipitation forms.

Such efforts represent a continuation of research programs that have lead, and will continue to lead, to improvements in weather forecasting.

Category: Meteorology

Comments Off

Is our December abnormally warm?

Posted on December 21, 2015 by WeatherGuys Editor

Cooper Armstrong of Madison works on his chipping game on Dec. 9 before a round at Odana Hills golf course, which reopened so golfers could take advantage of this month’s warm temperatures. Photo credit: John Hart, State Journal archives.

The mildness of the first half of December in southern Wisconsin has probably not escaped anyone’s attention.

Despite the first visit of relatively cold air we just experienced over the weekend, both Madison and Milwaukee have already recorded the second warmest first halves of December in their respective records. Through Dec. 16, Madison’s average temperature for the month was 39.7 degrees, a full 14.4 degrees above the average.

How rare is such a warm first half of December? Of the 10 record-warmest such periods in Madison history, five have occurred since 1998 (the record-warmest year). That is a rather alarming observational fact that strongly supports the myriad other observations that document the reality of global warming.

And since we are likely to record above normal temperatures for a majority of the remaining 10 days of this December, it is likely we will end up with one of the warmest Madison Decembers of all time. This follows a warm November where average temperatures in southern Wisconsin were 5-6 degrees above normal.

This warmth will ensure that the freeze of Lake Mendota will be delayed well into January, perhaps long enough that we will make a run at the latest freeze ever, which is Jan. 30. Stay tuned for more updates on what may be taking shape as a strange, record-setting winter.