Forecast Blogs

Record Breaking Weekend, Then Some Weak “Storms”

Current Radar 

We hit 73° today, three shy of the record 76° set in 2007.

Not seeing any rain on the radar tonight, although we can’t rule it out. Radar looks pretty clear to our SW.

Saturday – Record High Temps – Early 61°, High 74°

The cloudy, muggy December pattern remains. No rain expected, but a little drizzler can’t be ruled out.

74° would be a record for December 12. The record is 70°, set in 1873. Eighteen seventy three!

MIT Class of 1873:

We aren’t the only ones expecting a record high; these circled cities are too:

We can do it!

More Record Heat Sunday? High 76°

Most of Sunday should by like Saturday. But hotter! High 76°!

That would break the record temp for December 13, which was 75°, set in 1927.

Storms Late Sunday Night: Why It Won’t Be A Big Deal

A squall line will cross the Mississippi River Sunday night, then weaken as it pushes into Middle Tennessee.

ETA

Bedtime Sunday night, maybe a bit later. Here’s the data:

The GFS model

The Euro Model generally agrees with the GFS model, except a bit slower,  by three hours or so.

The NAM4 Model

Severe?

We don’t think so.

Reason 1 – The Tilt

All the models have this thing weakening on arrival.

Reason 2 – No CAPE

Gotta have at least some Convective Available Potential Energy (CAPE) to make severe weather.

You don’t care about the science of this. We’d need CAPE, got no CAPE.

Reason 3 – Weak Lapse Rates

Reason 4 – There are other reasons, but let’s just end with: Smart People Say So

The Storm Prediction Center has excluded us from its severe weather outlook:

Analogs aren’t impressed:

And our NWS is all “meh.” This afternoon, they wrote:

“Overall, the potential for thunderstorms looks even much less than this time yesterday, and even then it was not great. Lightning strikes with this convection will be few and far between due to [a lack of] instability.… This event almost has no CAPE associated with it, but good low level shear, so gusty winds are the main concern.”

So Why Are You Even Talking About It?

It’s what we do.

72 hours ago, models suggested supercells strafing Middle Tennessee Sunday night. But, those were just one set of models, they were so far away, and they sounded kinda unbelievable at the time. Turns out, it was not be believed.

To be fair to this system, there will be impressive storm-making ingredients, namely, the shear – winds increasing/turning with height. Storm Relative Helicity values are 451 m2/s2 up to 1km, 595 m2/s2 to 3km. Shear is 47kn to 1km, 63km to 3km. (Fellow weather nerds: that’s from the GFS). That’s a looot of shear.

But it’s got nothing to work with.

So, maybe a big wind gust with this thing — that’s the worst we expect so far.

Rain?

Yeah. It’ll rain a lot.

After All That, We Cooling Off?

LOL no. What? You think it’s December or somet…wait.

After 61° Monday, we’ll ease into the 50°s by mid-week, then likely a lot colder next weekend. Stay tuned.

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Categories: Forecast Blogs