The first weather class I took in college, Introduction to Meteorology, explained many basic features that a weather geek like myself found fascinating. One process that has been covered numerous times in many different geoscience areas is orographic uplift.

When I initially heard the term in World Geography, I was intimidated by the phrase. However, I later learned over and over again the way a mountain acts as a weather maker. The word “orographic” refers to a mountain while “uplift” addresses the motion that mountains force air to take. It all begins with a parcel of traveling air. Once this parcel reaches a significant obstruction (like a mountain), it is forced upward. One foundation of meteorology is that warm air can hold more moisture, water vapor, than cold air can. Therefore, the parcel of air can hold less moisture as it is forced upward into cooler air. This causes condensation and precipitation on the windward side of the mountain. Once air passes the apex, it warms as it travels down the mountain. The parcel is exhausted of excess moisture at this point, causing dry weather on the leeward side. This process occurs in the western United States because of the Sierra Nevada and Rocky Mountain ranges. For example, parts of California receive adequate rainfall each year while the Midwest, or leeward sides, are desert. The same occurs in western Europe. Although an easy lesson in Meteorology, orogarphic uplift can be a major element in weather.

By the way: For those of you trying to validate the weather folklore from Monday, I have two answers for today.

1) When clouds appear like towers, the Earth is refreshed by frequent showers. These towers refer to a cumulonimbus cloud, a cloud associated with severe weather.

2) Rain foretold, long last. Short notice, soon will pass. I do not claim that this is the original explanation, but the phrase applies for the present day. When there are “popcorn” showers, they are not forecasted days in advance like long-lasting meso complexes are. Keep reading for more explanations!

The Monday afternoon map discussion video is on the server:

http://beta.abc3340.com/weather/video.hrb

I know the summer solstice was last week, and you can sure confirm that by looking at the maps today. All of the good action in the mid-latitude westerlies is way up north; over the northern U.S. and Canada. The weather here will be very slow to change over the next seven days.

Late June in Alabama means very warm and very humid weather, and there will be sufficient moisture for scattered showers and storms on a daily basis. A weak upper air circulation center is north of the state now, and should meander around while weakening through mid-week. The WRF still suggests the best chance of a shower tomorrow will come along and south of I-59, while the NAM wants to paint the best coverage of showers over the southeast part of the state, generally southeast of Montgomery.

There simply isn't enough evidence to make us vary much from the typical summer forecast for the rest of the week and into the holiday weekend.

TROPICS: Watching the mass of storms over the Gulf of Mexico; there seems to be a 40 to 50 knot speed max in that region at 300mb (jet stream level), not what you want to see for tropical development. Elsewhere the tropics are quiet....

I have about 10 people in line waiting to get into the office to see me about various issues (I hope nothing bad... I will keep this short today and watch the video for the long story...

The ABC 33/40 Podcast for Monday afternoon, June 27 is now being served by our RSS feed.

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The Monday morning map discussion video is on the server:

http://beta.abc3340.com/weather/video.hrb

Good to be back after a week off. Thanks to my associates for covering all the bases during the vacation... we crank out plenty of weather products and the daily schedule can make you dizzy.

We have an upper low showing up this morning just west of here, and both the WRF and the NAM show the circulation over central Mississippi this afternoon. This should generate a few scattered showers or storms later today, and both models agree the best coverage of showers will be along and north of U.S. 278, or north of a line from Hamilton to Cullman to Gadsden. Once again, I caution you trying to tell you exactly when and where it will rain on a summer afternoon is very, very hard to do. We will struggle with this issue for the next two months, and you will hear the words "scattered, mainly afternoon thunderstorms" often in the forecast.

Tomorrow, the models suggest the best coverage of showers will be along and south of I-59, or south of a line from Tuscaloosa to Birmingham to Gadsden.

The models lose the upper low later in the week, and with warmer temperatures aloft we figure the summer showers will thin out by Thursday and Friday.

HOLIDAY WEEKEND: There seems to be some hint of a surface front north of us this weekend, but I am not sure that will affect the weather here. Bottom line is that we are looking at pretty typical summertime weather for the Independence Day weekend. Hot, humid, a partly sunny sky, and the risk of a passing afternoon storm in spots. Afternoon highs not too far from 90 degrees.

TROPICS: Lots of clouds in the Gulf of Mexico, but nothing organized this morning. Elsewhere the Atlantic basin is quite and tropical storm formation doesn't seem very likely for a while...

Will have the afternoon map discussion video posted by 3:30!

The ABC 33/40 Podcast for Monday, June 27 is now being served by our RSS feed.

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