Forecast Blogs

Fourthcast! USA! USA! (Rain Likely)

Wednesday – Showers/Thunderstorms Possible, High 83

(7 am 66 . 10 am 77 . 1 pm 82 . 4 pm 84 . 7 pm 81 . 10 pm 74).

Our NWS gives us 40% chance for showers and thunderstorms. Those rain chances increase later Wednesday night.

Fourthcast – Rain Likely (but don’t panic…yet), High 81

(7am 68 . 10am 76 . 1pm 80 . 4pm 81 . 7pm 79 . 10pm 74)

The weather pattern is shifting. The giant meandering low pressure center which gave us our cool temps will finally get a job and move out. In its place, a “Bermuda High.”

No, not that. This:

When winds start blowing from out of the south, it transports higher temps, humidity, and a lot of rain-making moisture. This process begins Wednesday, continues through the Fourth and into the weekend.

The good news is temps will start warming after the Fourth. Here’s your afternoon temperature Fourthcast (4 p.m.), with temps at or just under 80:

The bad news: Rain is likely on the Fourth, y’all. As we near the 4th, our NWS has increased rain chances to 70%, but there is hope, depending on the weather model you believe:

American (GFS) weather model has it raining from I-65 to East Tennessee.

This is how much rain this GFS thinks will fall between 10 a.m. and 1 p.m. on the 4th:

GFS rainfall between 4 p.m. and 7 p. m.:

Rain lines up along and east of I-65 for fireworks:

Since it’s the 4th, let’s ask another American model, the NAM: Will it rain on the 4th?

The NAM sends the rain along and east of I-65, in general

agreement with the GFS. Here’s the NAM at 7 a.m.:

By 1 p.m., the NAM moves the rain east of us:

Rain my try and sneak back in for fireworks, but the bulk of the rain is gone by 7 p.m., so says the NAM:

The WRF model really isn’t in range yet (it’s better 48 hours in), but it appears to favor a rainier day than the GFS and NAM, above.

The Europeans make a good weather model, but the last time I checked, we won the Revolutionary War (and, if you’re keeping score, the War of 1812, WW1, and WW2)*, so as far as I’m concerned the European model is invalid on the Fourth of July. The Euros predictably rain us out for most of the Fourth, so I retaliate with this:

Bottom Line: rain is “likely” but not “definite.” Our NWS (real live forecasters who actually live here, read all the models, and show their work — which is everything your crap app does not do) thinks we’ll get under 0.50″ of rain.

Note that we are right on the “border” of the rain/no rain line, and models are rarely if ever so precise 48 hours away. So, a wobble 30 miles west or east could rain us out or keep us dry all day.

This sums it up best:

*Attention history nerds: there are technical problems with calling some of these wars “wins” vs. “Europe” because many European countries were our allies. I was a History major. I get it. Just roll with me here. Thanks!


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