One more mostly dry day

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Main Threats

Today: The heat this afternoon.

Summary

Look for a mostly dry day today. Just be aware that we could see an isolated afternoon/evening storm. Again, most of us will stay hot, humid, and dry.

Over the weekend, a slow-moving cold front will make its way into our area. This will bring widespread showers and storms, especially Saturday evening/night and into Sunday. We may squeeze in a mostly dry day Saturday, but Sunday is certainly looking wet. Those rain chances look to hang out with us through at least Tuesday.

While we may see some storms over the next several days, widespread severe weather does not look likely at all. Just be aware that some of the storms could produce very heavy rainfall, frequent lightning, and gusty winds.

Discussion

It looked dark and threatening outside for the better part of our Thursday evening, but those heavier storms were just to our west. Normally, we would have looked for them to move our direction, but the flow was opposite what we would expect and the storms were moving toward Nashville. I noticed several flood advisories were issued for those storms around Sparta and Cookeville. Today, we shouldn’t see that kind of activity, but we could see heavy downpours over the weekend and into next week.

Tropics

The big tropical headline now is Tropical Storm Florence. That storm continues to track westward and models are beginning to insist that we keep our eyes on her. The tricky thing is that she’s an odd storm. First, she strengthened this week into a cat 4 when not one single model or forecaster thought that was possible. Now, she’s weakened back to a tropical storm, but you have to keep an eye on these storms that have been that powerful at one point in their life. They seem to more easily restrengthen.

And that’s just what we think Florence will do. In fact, it looks like she will restrengthen into a major hurricane.

As for climatology, well, it does not favor a landfall from Florence. Since hurricane records have been kept, 33 storms have been within 100 miles of Florence’s current position. None of them made landfall in the U.S. Unfortunately, Florence may defy climatology and make a run for the East Coast next week. Stay tuned. The map below was produced by @philklotzbach, showing the 33 storms that have been near Florence’s position.

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WeatherTAP’s wind model suggest Florence may defy climatological odds and threaten the East Coast next week.

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Don’t forget that we still have two more disturbances that are likely to become named storms. They are those red areas you see over near Africa. Those will be Helene (heh-LEEN) and Isaac (EYE-zik).

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Meanwhile, it’s looking like Hurricane Olivia may threaten Hawaii next week. Fortunately, it looks like she will weaken into a tropical storm before impacting the islands.

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Records

The relentless and historic heat wave of 1925 continues. On this date, Clarksville (just northwest of Nashville) recorded a high temperature of 112 degrees. This nearly tied the hottest all-time temperature ever recorded in Tennessee (113 on Aug. 9, 1930). Numerous other locations across the state surpassed the century mark for high temperatures.

On this date in 1970 a lightning bolt hit a group of football players at Gibbs High School in Saint Petersburg, Florida. Two players were killed instantly. All 38 players and four coaches were tossed into the air and off their feet when the bolt hit. Always be mindful of those skies if you’re out and about during the afternoons. Those pop-up storms can blow up quickly!

News

As I’ve been mentioning, the tropics are on fire. They were so quiet for so long but they have certainly woke up now. I wrote an article last week for the papers about hurricanes. It was published this week, and I will share that with you here. I hope you enjoy the article, and I hope you have a great weekend!

Hurricane

The month of September brings the peak of hurricane season. This is a good time to review our hurricane knowledge!

The peak of the hurricane season comes as the summer sun has finally warmed ocean temperatures enough to support tropical storms. Water is slow to heat up and cool down, so it takes time for the sun to heat the water up.

Hurricanes form when ocean temperatures warm to at least 80 degrees. That is the temperature the water must reach for evaporation to put enough water vapor in the air to feed these storms. Hurricanes are like our afternoon summer thunderstorms here on the plateau that thrive on heat and humidity.

Once tropical storms form, they need something to help them rotate about a single point. This is where the earth’s spin comes into play. The rotation of the earth gives rise to the Coriolis Effect, which helps these big storm complexes develop rotation.

Once that rotation reaches a maximum sustained wind of 74 mph, the storm is classified as hurricane. The strongest storms are then found around the eye of the storm. The eye is a calmer region found at the center of the storm.

Now that an eye has formed, the hurricane will undergo what we call eyewall replacement cycles. These are poorly-understood cycles that the hurricane undergoes. The storms intensify around the eye and stay strong up to several hours. Then, the storms begin to weaken and the eye collapses. The storm is at its weakest during an eyewall replacement cycle. The hurricane is at its most intense just as an eyewall replacement cycle is completed.

While this hurricane season has thus far been a quiet one, we can’t let our guard down. The Atlantic hurricane season ends November 30th, giving us plenty more time for concern.

 

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