International Falls, Minnesota: Frigid Begets Super-Frigid

By: 24hourprof, 9:48 PM GMT on December 12, 2013

The temperature at International Falls, Minnesota, plummeted to minus 33 degrees Fahrenheit early Tuesday morning (Climate Summary for December 10). The low occurred between 4 and 5 A.M. CST on December 10, but, if you were a rookie forecaster working during the evening of December 9, you might not have predicted such an extreme minimum.


A portion of the 00Z surface analysis on December 10 (6 P.M. CST on December 9). Full analysis. Courtesy of WPC.<...

Weather Forecasting Microphysics

Updated: 2:48 PM GMT on December 13, 2013

Ice Storm over the Southern Plains: A Case of Differential Temperature Advection

By: 24hourprof, 5:04 PM GMT on December 07, 2013

I'm sure some readers have heard professional forecasters allude to differential temperature advection. well, the ice storm over the Southern Plains on Friday (December 7) is an example of one of the impacts of this process.


The meteogram at the Dallas-Fort Worth Airport from 20Z on December 5 to 21Z on December 6, 2013. Courtesy of the University of Wyoming.

For starters, check out the meteogram above, which shows conditions at the Dalla...

Synoptic Meteorology Short Blog

Updated: 1:38 PM GMT on December 08, 2013

Final Thoughts on Supertyphoon Haiyan

By: 24hourprof, 4:32 PM GMT on December 05, 2013

Note: Some of the following text was written for Edition 6 of my book, A World of Weather: Fundamentals of Meteorology.

Like the outbreak of tornadoes over the Middle West on November 17, I have some final thoughts about Supertyphoon Haiyan (Yolanda), which ravaged the Philippines on November 8. Specifically, my general goal here is to update readers on the science of the eye of hurricanes/typhoons and the processes by which tropical cyclones intensify. <...

Hurricane Tropical Forecasting

Updated: 8:35 PM GMT on December 09, 2013

Final Thoughts about the Tornado Outbreak on November 17

By: 24hourprof, 10:08 PM GMT on November 25, 2013

In my previous blog, I asserted that tornado outbreaks during November are not rare, even the prolific ones like the one that struck the Upper Middle West on November 17. At the same time, I recognize that there were facets of this outbreak that were indeed rare. According to Jeff Masters, "Pretty strange to see November tornadoes here in Michigan; there had been only six prior to Sunday, dating back to 1950, and now the tally is increased by four."


Severe Weather Synoptic and Mesoscale Analysis

Updated: 1:13 PM GMT on November 27, 2013

November Tornadoes: My Two Cents

By: 24hourprof, 8:40 PM GMT on November 20, 2013

We live on a very old planet whose natural forces remain untamed. The ground still shakes beneath our feet. Volcanoes spew ash and lava. And, because the sun shines unevenly on a nearly spherical Earth, it is normal for the weather to be extreme.

I wrote this characterization in the third edition of A World of Weather: Fundamentals of Meteorology. I still believe that it applies, so I am usually very cautious about using the word, "rare," in the context o...

Tornado Statistics Mesoscale Forecasting

Updated: 1:18 PM GMT on November 27, 2013

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About 24hourprof

Retired senior lecturer in the Department of Meteorology at Penn State, where he was lead faculty for PSU's online certificate in forecasting.