What was the weather during the Titanic’s fateful voyage?

Posted on April 16, 2012 by Weather Guys Editor

There were northerly winds over North Atlantic in the months before the RMS Titanic left port. These winds likely played a role in pushing icebergs farther south than normal and into the Titanic’s path.

When the Titanic left port in Queenstown, Ireland, on Thursday, April 11, 1912, it sailed under brisk winds from the north-northwest at 15-20 knots and a temperature of about 50 degrees.

Two days earlier, well to the west in Boston, a few thousand fans shivered in the cold and snow flurries as the Red Sox beat Harvard University 2-0 in the first game ever played at Fenway Park.

On April 12, the winds were from the west-southwest at about 15 knots and the noon temperature was about 60 degrees. As the ship continued west, the skies got cloudier as a weak cold front approached. The noontime temperatures on Saturday, April 12, were still around 60 degrees, but another cold front (associated with the previous Fenway flurries) was to the west and north of the ship.

As the Titanic passed through the second cold front on Sunday, April 14, the winds switched to northwest at 20 knots. The noon temperature was around 50 degrees, but by 7:30 p.m., the temperature was 39 degrees.

On Sunday, nighttime temperatures dropped below freezing, and the skies cleared and the winds calmed. A large Arctic air mass was over the area on the clear, star-lit night with subfreezing temperatures and calm winds that resulted in a sea “like glass.”

Icebergs were known to be in the region, but the calm winds made spotting them difficult. To spot icebergs during the night, lookouts searched for wind-driven waves breaking around their bases.

The ship struck an iceberg at 11:40 p.m. Sunday, April 14.

On Monday morning, after the sinking, one survivor reported a breeze that came up around dawn to add to the morning chill. Photographs of the rescue that morning show small waves on the ocean surface, confirming that report.

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What is dual-polarization Radar?

Posted on April 9, 2012 by Weather Guys Editor

The next generation of weather radars, which are currently being installed throughout the United States, will improve observations of the interior of storm systems. These radars are called dual-polarization radars.

Radar, an acronym for Radio Detection And Ranging, consists of a transmitter and a receiver. The transmitter emits pulses of radio waves outward in a circular pattern.

Precipitation scatters these radio waves, sending some energy back to the transmitting point where it is detected by the radar’s receiver. The intensity of this received signal, called the radar echo, indicates the intensity of the precipitation.

A radio wave is electromagnetic energy. That means it has electric and magnetic fields, which are oriented perpendicular to one another. The orientation of these oscillations is referred to as polarization.

It’s the same principle at work in a polarizing filter for a camera, or polarizing sunglasses. Rotate the filter, or glasses, while looking through them at a portion of the sky away from the sun; at a certain orientation, the intensity of the sky’s light will be reduced. This is because the filter is removing polarized light that is not aligned with the filter.

Typical weather radars transmit and receive radio waves with a single orientation of the electric field. Dual-polarization radars emit radio waves that alter their transmitted pulse between horizontal and vertical polarizations. The additional information on polarization improves the precipitation rate measurement as well as determining the type of precipitation (snow, rain, freezing rain and hail).

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How did this recent warm March impact maple sap harvesting?

Posted on April 2, 2012 by Weather Guys Editor

Tapping maple trees usually occurs in late winter and early spring. In Wisconsin, March is a prime month for tapping sugar maple trees and this is when the sap is sweetest. But, only about 2 percent of the sap is sugar, so it has to be boiled down to remove the water and increase the sugar concentration.

Weather is a crucial factor for a good harvest of maple sap for syrup. Good weather conditions for syrup production are nighttime temperatures in the 20s and sunny days with temperatures in the 40s. This alternate freezing and thawing temperature cycle causes pressure changes inside the tree that makes the sap flow. If the nighttime temperatures are too cold, it takes a longer for the sap to warm up and “run” in the daytime. If the temperatures are very cold, the sap may not run at all. If the nighttime temperatures are too warm, the sap will not flow.

Our March weather has been terrible for harvesting sap for syrup. Minimum temperatures throughout Wisconsin were 10 to 15 degrees above normal, and maximum temperatures soared into the 70s and 80s.

Tree species have adapted to different climate conditions, particularly temperature and moisture. Sugar maple trees don’t live in geographic regions where summer temperatures frequently reach 100 degrees or where the winter temperatures regularly drop below 0 degrees. In the United States, the best climate conditions for sugar maple trees are found in the northeastern and north central regions of the country. Unfortunately for maple syrup lovers, the Northeast has also experienced warm weather this March.

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How unusually warm has the March weather been?

Posted on March 26, 2012 by Weather Guys Editor

What an amazing warm spell! March 14 was the first day of five consecutive days in which record-high temperatures were set in Madison. This matches the longest consecutive-day streak for setting record highs in our city’s history (the other two times were in the 1950s).

Had it not been for the thundershower we received on the morning of March 19, we would certainly have set the all-time record on that day as well. We then went on to shatter the record on March 20 (81 degrees when the record had been 77), followed by another record-setter on March 21 (83 degrees for the warmest March day ever in Madison). All told, seven of eight days on which an all-time record high temperature was set — and it could have been eight straight days

During this streak, Madison also doubled the number of times the temperature has reached 80 degrees or higher in March. Before March 2012, this had happened only five times, never earlier than the 29th of the month. March 2012 has seen five such days all by itself (all in one week!)

This month has also seen the warmest average daily temperature for a March day of all-time (70 degrees on March 17, a figure that comes from the average of the daily high temperature, which was 80 degrees, and the low, which was 60 degrees).

There are those who remain unconvinced of the fact that changes in the atmospheric composition have had a discernible effect on the behavior of the atmosphere and climate systems. Some of these skeptics are major party candidates for the presidency. In the face of this recent, absolutely unprecedented, prolonged extreme weather event it is hard to consider this a reasonable position.

Were there a general suspicion among college basketball experts that the NCAA tournament officiating was not honest, even those resistant to believing this might reconsider their positions if one or two or three No. 1 seeds lost (for the first time in the history of the tournament) in the first weekend. There is a reasonable analogy here to what we have recently experienced in our weather. The room for reasonable skepticism is fast disappearing.

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How unusual is this current warm spell?

Posted on March 19, 2012 by Weather Guys Editor

Our high temperature of 78 degrees Farenheit on March 14 set the all-time record for the date and established a new record for the first 78-degree F temperature of the year, breaking the standing record of March 23, 1910 — over a century ago.

The fact that daily records have not been broken every day during this warm spell testifies to the fact that such warm mid-March days are not unprecedented in Madison’s weather history. One of the unusual aspects of this particular spell of warmth, however, is the prolonged nature of it. Based upon departures from normal (normal being the 30-year average from 1981-2010), this warm spell really began on March 10 when our present streak of days with daily temperatures at least 10 degrees above normal began. It is likely that the streak will not end at least for the next seven or more days, so it will end up being nearly two weeks long.

As warm as it has been, coming so close to 80 degrees last Wednesday made us wonder when Madison’s earliest day at 80 degrees occurred. Turns out this warm spell provided a record in that category, too.

On March 15, Dane County Regional Airport, the official reporting station for Madison, recorded a high temperature of 82 degrees Farenheit — breaking the record for all-time earliest 80-degree day by two full weeks.

Prior to last week, the record was March 29 when, in 1986, the high temperature for the day was 82 degrees Farenheit (the monthly record also recorded on March 31, 1981).

Prior to last week, only five times in the last 43 years had the temperature made it to 80 F in Madison during March (1978, 1981, 1986, 1991 and 2010). In none of those cases did the warm temperatures last nearly two weeks without interruption. Thus, we are in the midst of a truly unusual warm spell.

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