Yesterday afternoon around 3pm Central, a violent tornado touched down near Newcastle, OK, about 20 miles south of Oklahoma City. The massive, mile-wide tornado traveled northeast for nearly 20 miles and remained on the ground for approximately 40 minutes. Included in its path were two schools--Plaza Towers and Briarwood Elementary--as well as the city's hospital, Moore Medical Center, all of which were destroyed.

Damage survey teams are currently conducting surveys of the Newcastle, Moore, and south Oklahoma City areas. As of this afternoon, their findings confirm the tornado's rating as a strong EF5 (200+ mph (322+ km/h) winds). In fact, scientists estimate that the amount of energy released during the storm's life span was several times that of the power of the Hiroshima bomb.

It's looking more and more likely that Monday's tornado may make weather history as the third deadliest tornado in the Oklahoma City area, and possibly one of the top 5 most damaging tornadoes in U.S. history. The last time a tornado of this magnitude tore through the Moore community was on May 3, 1999. That storm, which also rated an EF5, caused 36 fatalities. The current death toll stands at 24.

For the latest updates on the Newcastle/Moore tornado and the ongoing May 18-21, 2013 tornado outbreak, follow this link to the NWS Norman, Oklahoma WFO page.

At the start of the week, temperatures across Minnesota, Wisconsin, and Iowa soared into the triple digits. For many cities, including Omaha, NE (which hit 101°F) and Minneapolis, MN (which hit 98°F), it was the earliest in the year they've ever experienced such high temperatures. The hottest temperature of all--108°F--occurred in Tekamah, NE, with Sioux City, IA coming in a close second at 106°F.

Not even 2 weeks ago, many of these same cities were 50-70°F colder and blanketed by 1-12+ inches of snow, thanks to a very rare May winter storm. The May 1-3 snowstorm set all-time snow records for the month of May, including for the cities of:

• Rochester, MN--it received 7" of snow (previous record 2" on May 4-5, 1944);
• Sioux Falls, SD--it received 1.5" of snow (previous record 0.1" on May 1, 1967) ;
• Omaha, NE--it received 3.1" of snow (previous record 2" on May 9, 1945);
• and Osage, IA--it received 13" of snow. This is also the most snowfall to occur anywhere in the state of Iowa during the month of May.

Topeka, KS, Kansas City, MO, and Des Moines, IA received 1 inch, 2.5 inches, and 6.9 inches of snowfall, respectively. Only once before (May 3, 1907) have these three cities experienced a May snowstorm. (That storm's snow totals were 3.2" at Topeka, 1.7" at Kansas City, and 1.2" at Des Moines.)

Back-to-back extreme and opposing events like these have led to the phrase "weather whiplash" being tossed around in recent weather news, but what exactly does it mean?

The official start of hurricane season in the Eastern Pacific was yesterday, May 15, and the basin's tropical weather is arriving right on cue. The season's first tropical depression spun up yesterday morning several hundred miles southwest of Acapulco, Mexico and by early afternoon was named Alvin, the season's very first tropical storm.

However, it looks unlikely that Alvin will go on to become the EPac's first hurricane. Vertical wind shear has already begun to weaken the storm and will continue to affect it during the next 3-5 days.

No watches or warnings are currently in effect, as Alvin is tracking west-northwestward out to sea.

Our nation's weather radar just got "tricked out."

At the end of April, the NOAA National Weather Service completed a major software and hardware upgrade to its 122 weather radar sites. The upgrade, which cost approx. $50 million USD ($225,000 per radar site) to complete, enhanced the current fleet of WSR-88Ds from their conventional Doppler technology to that of dual-polarization ("dual-pol").

So, what's the difference? Unlike conventional Doppler radar which works by sending and receiving signals in the horizontal, dual-pol radar sends and receives both horizontal and vertical pulses of energy--in essence giving meteorologists a 2-dimensional picture of whatever is in the air. Another advantage of dual-pol radar is that it makes it possible to identify real precipitation from birds, bugs, and other non-weather related airborne objects. It can also specify the type of precipitation (rain, snow, hail, etc.) that's occurring.

Ultimately, this technology means timlier and more accurate forecasts for the public. For example, with the use of dual-pol images, forecasters will be able to do things like tell what locations may be experiencing all snow in comparison to those seeing a wintry mix, and detect/identify flying debris from tornadoes (and therefore the presence of a tornado) without first having to confirm it through spotter accounts.

To learn more about dual-pol technology and this recently completed project, read through this list of FAQs put together by the NOAA.