Cool Gravity Waves over the Gulf this Morning

[Sam Sagnella]

Randomly checking satellite images of the tropics this morning and stumbled across these cool gravity waves over the GoM; the time of this image is 1445UTC on November 17.

 

[Glen Romine]

Where in the Gulf are you looking? All I see are cloud streets.

Glen

 

[HAltschule]

Aren't gravity waves normally much smaller in size than what is seen on that satellite picture. Something like 1/10th the size of those cloud streets?

I haven't really studied much gravity wave meteorology for many years and last I knew, they were still very difficult to find/forecast. It was usally after a svr event or big snow enhancement that a g-wave was found. Are there any webpages or models that forecast or observe g-waves better nowadays?

 

[Jeff Snyder]

There are several common sources for gravity waves, including the oscillations of an intense updraft. The features in the pic that Sam posted are cloud streets / boundary layer rolls. If I'm not mistaken, gravity waves tend to have little preference for wind direction -- they spread out from a source in all directions (at least initially). BL rolls, on the other hand, are aligned in the same direction as the low-level flow. Looking at the surface map (and RUC analysis) across the Gulf region this morning, we see pretty strong north-northeast surface winds, which align very well with the north-northeast orientation of the cloud (streets). In addition, convective rolls/cloud streets tend to be rather stationary, since they are aligned with the boundary layer flow. If you loop that vis sat image, you'll see that the more prominent rolls are indeed quasi-stationary -- they do not propagate out as a gravity wave would.

 

[Sam Sagnella]

Obviously I don't know what the hell I'm talking about :lol: . I should have looped the image but it appeared from the still that, along an E-W line from roughly north of Brownsville to south of Tampa, there's an area in which these features "bow away" from each other, which I took to be an indicator of 'outward' motion. Thanks for the corrections, and though I misidentified them they're still pretty cool.

 

[Jeff Snyder]

I see what you're saying... There's an area of enhanced Cu aligned pretty close to where the quasi-stationary cloud streets are kinked. It's cool to see the kinks propagate to the south-southwest, much like what would happen if you layed out a long piece of string, then snapped your wrist to iniatiate a wave on that string (which then travels down that string). Cool image nonetheless.