Wednesday, April 13, 2011

Spring vs Winter

The battle rages on around most of the country. This is the time of year where complaints start to roll in. Too much rain in Oregon. Too much heat in the Southwest. Too much snow in the Northeast! I have been hearing plenty of them and I am sure you have them too! Here in the Northwest, March left us with plenty of wet weather and April hasn't been too stellar either. Take a look at this map which was used on the Fox 12 Weather Blog (those guys do a really good job over there) that really sums up the wet Spring:

How about the Great Plains? They had a record-breaking winter and now spring and winter are REALLY going at it. The topography of the United States allows for a perfect set up for this battle. Cold air from Canada filters down the east side of the Rockies at the same time warm air pushes up the Midwest from the Gulf of Mexico. With no mountain chains to block either air mass, they clash and the result is awesome but very dangerous and deadly.

Essentially, warm air and cold air don't get along. The result causes instability in the atmosphere and can result in any number of severe weather events. Here is a look at the clashing of air masses on weather maps. These maps reflect a severe weather outbreak from last week that stretched from Minnesota to Michigan.

Note the map in the upper left-hand side. This is the temperature of the air at about 5,000 feet. Notice the warmer air pushing from the south to the north and the contrasting cold air moving down from the north. Check out this radar image from one of the storms that moved through Wisconsin.
The National Weather service receives reports of damage from these storms, anything from wind damage to tornado and hail damage. This is a map from the same event:
This sort of weather is my dream job! To forecast it. To capture it. To live it! I sit at work and do my best to forecast severe weather across the country each day. The spring is the best time for this across most of the United States. In fact, as I look at the maps today, the Midwest is in store for another round of potentially severe weather Thursday and Friday!

Look at the bulls-eye of low pressure showing up over Nebraska, Oklahoma, Missouri and Arkansas. Notice the warm air and cold air mixing? The black arrows indicate wind direction and speed. Lots of mixing of warm and cold air, so this is an area of concern for severe weather on Thursday and Friday. My thoughts are echoed by the Storm Prediction Center:

Great set-up for the next few days for severe thunderstorms and tornadoes! Gotta love this time of year.

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