McWeather or Not


Mild Here, But Not in Tornado Alley

Dennis McTighe

From today through Sept. 10 the sun will set at 7:15 p.m. or later. Our latest sunset occurs on June 21 at 8:08 p.m. and sets at that time until July 7.
On this date in 1997 the ocean temperature in Laguna was already 72 degrees thanks to a very strong El Nino event. On April 5 of that year the water temperature reached 70 degrees and didn’t drop below 70 until Nov. 20! What an incredible run that was.

Also on April 11, one of the biggest Southern Hemisphere swells of all time rocked Southern California beaches.

April is the time when severe weather really comes on anywhere east of the Rockies. After exiting the Pacific Northwest a low pressure and its associated cold front plow through the Rockies and set their sights on the Great Plains and points beyond. Meanwhile a flood of warm moist air is streaming northward from the Gulf of Mexico sending temperatures into the 70s and 80s with lots of humidity and high dewpoints up into the low 70s. Once that cold front clears the Continental Divide with its cold west and northwest winds, it collides with the warm southerly flow out of the Gulf of Mexico. With a low level jet stream from the west and a surface low connecting the warm and cold front at a 90 degree angle the dynamics are in place for an outbreak of really dangerous weather as witnessed over the past couple of weeks.

The cold front blasts east out of the Rockies and crosses the dry line in eastern Colorado and Wyoming and merges with the giant pool of warm humid air and the explosion begins. Within minutes clear sunny skies suddenly become very dark and foreboding as huge cumulonimbus clouds begin to mushroom rapidly toward the heavens, reaching as high as 50,000 feet above the ground. Now we have what is called a super cell thunderstorm, the most violent of storms. Frequent intense lightning and ear piercing thunder, then baseball size hail, torrential rain capable of dropping two or even three inches of rain in just one hour, and with all the wind coming in all directions both at the surface and aloft, strong rotation begins and a mile wide F-4 tornado drops out of the wall of clouds with winds in excess of 200 mph.
These weather events are fascinating yet extremely dangerous. McWeather has witnessed such events as he volunteered to go storm chasing while in the U.S. Air Force weather school in Amarillo, Tex., in the heart of “tornado alley”.  Running out of room, Happy Easter, everyone, ALOHA!
Dennis McTighe served as a meteorologist at Hickam Air Force Base, Hawaii from 1969 to 1972, and was an NOAA forecaster  and earned a degree in Earth Sciences from UC San Diego and has been keeping daily weather records since 1958.

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