Understanding Summer Weather In Alabama

| May 29, 2017 @ 8:04 am

Meteorological summer begins this week, and here is a reminder about how it goes on summer days in Alabama…

*THE WEATHER RARELY CHANGES DURING JUNE, JULY, AND AUGUST: If you say “hot and humid with widely scattered afternoon storms”, then you will be correct 95 percent of the time.

*IT RAINS JUST ABOUT EVERY DAY IN SUMMER: The combination of a moist airmass and the intense daytime heating process usually leads to “scattered, afternoon and evening showers and thunderstorms”. These are rather random in nature, don’t move very quickly, and are very much hit and miss. Mostly miss. About the only way we get a really widespread rain event around here in the summer is the result of a tropical system moving into the Central Gulf Coast.

Nobody, and I mean nobody, knows where the storms will fire until we actually see them on radar by early afternoon. We might have a general idea where the best chance of thunderstorm initiation will be, but it is one of the great challenges of summer weather forecasting in Alabama. Most of these storms form between 2:00 and 10:00 p.m. But, on occasion, with a small scale boundary or other feature, you might have a late night or morning shower.

So many times people ask in the morning if it will rain in their town later that day during the afternoon, and the correct answer is that WE DON’T KNOW. Even when you see the storms forming on radar in the afternoon, they are usually widely spaced, and move erratically. One part of your town might see one inch of rain, but the other side of town is bone dry. Such is life with “scattered afternoon thunderstorms”.

*THE DREADED POP: “Probability of precipitation” is pretty much worthless in summer around here. Most days, the chance of any one spot getting wet is 20 to 30 percent. Of course, if you happen to be underneath one of the storms that form, you immediately think anyone that says the chance of rain is 20-30 percent is an idiot since you have no way of knowing the rain is only over you. Just to blow your mind, the chance of a storm forming on any summer afternoon in Alabama is actually around 80 percent, but due to the very scattered nature of the storms, the chance of your neighborhood getting one is only 20 percent or so. Confusing? You bet, and we do our best to stay away from “chance of rain” on summer days. It just doesn’t work.

*AFTERNOON STORMS CAN PRODUCE PROBLEMS: The greatest threat from a summer afternoon thunderstorm in Alabama is lightning; one storm can produce hundreds of very dangerous ground strokes. And, they can produce localized areas of damaging winds called “wet microbursts”. These often last for only a few minutes, and sometimes happen toward the end of a storm’s life cycle as the cell begins to collapse. Severe thunderstorm warnings are issued when this is a high probability.

*TORNADOES ARE VERY RARE IN SUMMER: Wind fields are light and variable from the surface to the tropopause on most summer days, and it is almost impossible for a tornado to form. The only time we see them is in spiral bands associated with landfalling tropical storms or hurricanes. And, when that happens, the tornadoes are usually very small and short lived.

*AFTERNOONS ARE HOT: We live in strange times. National media outlets on hot days will declare it to be some kind of emergency, breaking news or unprecedented. That is lunacy. Hot weather is the norm here from June through August, and often through much of September. Highs usually are in the 90s, but when an intense upper high forms over the state, we can hit triple digits. It has been as hot as 112 degrees in Alabama… recorded on September 25, 1925 in Bibb County. Note the month was September, and the year was 1925. Intense heat is nothing new here. And, it can come well before and well after meteorological summer.

*SOIL MOISTURE IS IMPORTANT: This is one factor many people don’t consider, but it is very important when it comes to the amount of heat we experience. When soil moisture is high, some of the sun’s energy is used to evaporate that moisture, which takes away from the amount of solar energy used to heat the ground, which in turn heats the air. You rarely ever see 100 degree days when the soil is moist. On the other hand, with dry soil and brown grass, temperatures can easily reach the triple digits.

*MOST BACKYARD THERMOMETERS DO NOT WORK WELL HERE ON HOT SUMMER AFTERNOONS: Almost every hot day, we hear from someone reporting a high of anywhere from 105 to 115 degrees. To properly measure air temperature, you need a thermometer in an instrument shelter, about six feet off the ground over grass. The shelter should have easy and free air movement, and it needs to be painted white. Needless to say, most backyard thermometers are not set up this way, and they wind up measuring the temperature of the instrument casing instead of the air. You really need an aspirating fan if you don’t have a shelter. Few “backyard” reports are accurate this time of the year.

I should also mention car thermometers are very inaccurate on hot summer days as well.

Hot weather in Alabama during the summer is just a way of life. Use you common sense and stay cool as best you can. On the blog here we won’t insult your intelligence with “heat tips” like “go into an air conditioned room”… we are well aware you know what to do if you begin to overheat.

The one “tip” that is urgent is this… look before you lock!

*HURRICANES BREAK THE ROUTINE: The core of the hurricane season comes in August, September, and early October, but the season itself runs from June through November. This keeps us on our toes.

So there you go. The weather in Alabama on a summer day will be hot, humid, hazy, and it will rain somewhere in the afternoon. We just don’t know where until we see the colored blobs on radar during the heat of the day. Welcome to the hottest season of the year…


Category: Alabama's Weather

About the Author ()

James Spann is one of the most recognized and trusted television meteorologists in the industry. He holds the AMS CCM designation and television seals from the AMS and NWA. He is a past winner of the Broadcast Meteorologist of the Year from both professional organizations.

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