Two weeks is too soon: long-range forecast vs. reality

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Hurricane Gert is currently southeast of the North Carolina coast (at 9:00 am on Tuesday, August 15, 2017). She is a Category 1 hurricane with sustained winds at 75 miles per hour. Expect her to turn toward the northeast today and strengthen a little before she becomes a post-tropical storm in the North Atlantic later this week. At this point, the only effect our coast will feel will be from swells and rip tides. As a friend of mine put it, “She’s a good surfing storm.”

satellite image

August 15, 2017 satellite image of Hurricane Gert off the southeastern U.S. coast.

What a difference two weeks has made! When I first started watching the forecast models and how they were handling the would-be tropical system, the GFS showed Gert slamming into the coast of Georgia at about 2 AM Thursday.  According to the National Hurricane Center’s 5 AM advisory today, by early Thursday morning, Gert should be far from land in the North Atlantic – still a hurricane, but not a threat to anything but transportation lanes on and over the ocean.

So, what did I learn or confirm from this little exercise?

A forecast two weeks in advance may have some hint of what is to come, but the details are far from exact. On Thursday, there will be a hurricane in the Atlantic, but the positioning, strength, and direction were all wrong. While I suspected as much, I wanted to prove it to myself and my readers with documentation.

Hurricanes aren’t the only events people ask about, tempting meteorologists to forecast several weeks in advance. The weather for the solar eclipse on Monday is another example. I’ve been asked how the weather will be on that day at certain locations since last month. It was difficult to hold my snarky replies in check. Anyone forecasting weather a month in advance is either looking at climatology, or she’s rolling the dice, throwing a dart, or guessing randomly. There is a chance to be right, but more than likely, she won’t be. So, I didn’t even try it, especially for an event inspiring such anticipation.

I have a sweet cousin getting married in upstate New York on August 26. Sure, I looked at what the models are predicting this morning while I was making the Wake Forest and Butner-Creedmoor forecasts. I didn’t like what I saw. Her outside wedding could end up wet. Of course, I could tell you that part anyway because that is the nature of planning an outdoor ceremony. Will I urge her to move it inside based on a long-range forecast model 12 days in advance? Heck no! I’m not even going to mention the possibility of another hurricane being just off the east coast that weekend.

Hopefully, she doesn’t read this blog. (Wink. Wink.)

NHC forecast

The 5 AM, August 15, 2017, National Hurricane Center forecast track for Hurricane Gert.