09.08.10

TD Hermine: Rain, Flooding, and…Tornadoes?

Posted in Tropical Weather, Weather News at 11:35 am by Rebekah

The rain from Tropical Depression Hermine made it up to Oklahoma this morning. Yesterday, Hermine began to cause some major flooding problems in Texas, and the rain is still coming down in some parts of Texas.

At the moment, Norman is experiencing a lull, as we’re in between a couple of the rain bands. However, we’re expected to get much more rain by tomorrow morning.

Here’s a look at the Hydrometeorological Prediction Center’s (HPC) rainfall forecast.

Yes, that’s right, 7.58 inches of rain forecast for central Oklahoma from this morning through tomorrow morning! According to the Oklahoma Mesonet, only 0.23 inches of rain has fallen so far in Norman (since midnight). Southern Oklahoma has already received almost 3 inches of rain.

But that’s not all Hermine may bring…the Storm Prediction Center (SPC) has a 5% risk out today for tornadoes from central Oklahoma down into north central Texas. Shear profiles are very favorable for supercells and tornadoes, thanks to Hermine, so the biggest problem will be instability. The SPC believes the greatest threat for supercells and tornadoes is in northern Texas, as that’s where the greater instability is likely to be. Tropical tornadoes tend to be difficult to see (wrapped up in all the rain) and predict (not coming from a traditional Plains supercell). However, these tornadoes are often quite weak (EF2 or less).

I’ve never chased a tropical system or tropical tornadoes before, but I am considering going out this afternoon to give it a try. I’ll give another look at some weather maps and decide this shortly.

In other news, Tropical Storm Igor (9th named storm so far) formed in the far eastern Atlantic this morning. It appears that Igor will become a hurricane in a few days, and possibly a major hurricane. However, Igor will likely recurve before it gets close to land. Models show that Tropical Storm Julia may also form in the next few days.

The 9th Atlantic tropical storm typically forms around October 4th, so we are already a month ahead of schedule, in what the NHC and Colorado State predicted would be an above average year for Atlantic tropical activity…

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