Meteorology Question

This is certainly appropriate query / post for the general Section.

I regret I can't provide answer.

Milo

I tried to find a legend for GOES water vapor loop you show, the only information I could find concerning the colors is here: http://www.goes.noaa.gov/enhanced.html

I tend to think it is what they call dry air now that I have studied some of the other images. I am just not sure if that is what keeps the hurricanes from growing larger.

Sooner or later someone with a meteorologoical background will stumble in on this thread.

Thank you.

Thank you. There are so many images and all of them have some kind of acronym behind them. I am just looking for a simple layman's explanation of the images.

netmaker,

You don't give the type of weather image - there are several different types of sensor used and simple or composite images are generated to look at weather systems in different ways. That includes IR, visible, topographic etc. and combinations of the above. See the list for example on this index page.

I usually look at the IR image, like this one, similar to what you posted. Notice at the bottom, the color scale is given for temperature. The "eye" of a storm is generally very cold: orange, red or nearly black. Set the selection back 24 or 48 hours and watch Hurricane Earl unfurl up the east coast. The grey, orange and red colors are temperatures below zero and they are correlated with moisture laden systems for sure. On these maps the temperatures above zero are shades of green - probably what is represented in the brown on your image. Whether that is an exact match for "dry" I wouldn't be too sure.

You can also see Earl in the "visible" satellite image if you replay from 48 hours. The data is a bit patchy, but you can see there's a lot more "cloud" stuff happening than what is contrasted in IR. On the basis of comparing the two, I would say, if your image is a 'visible' type, then the brown is cloud-free or dry, but if it's a IR type image, then the brown area is warm not actually dry.

Also I don't recognize the abbreviations TS and TD - what do they stand for?

The images came from STORM PULSE .

TS is Tropical Storm

TD is Tropical Depression

I am just looking for an explanation on some of the images and forecasts that are given.

The Link helps a lot!

Hopefully this image will appear larger the the originals (BTW, the image DID appear in the original post for me (on a Mac using Firefox). If you look at the lower right of the image, you can see the interpretation of the colors. Clearly the light brown is the low end of the scale, meaning drier air. It is unfortunate that they don't provide units or numbers. One logical interpretation would be 0% RH at the left and 100% RH at the right, but since Relative Humidity is highly temperature dependent, it could be some other unit such as grams per cubic meter.

Aha, now I see it is water vapour that's being imaged. So the brown areas are obviously the dry air, as netmaker suggested.

I know that hurricanes and other storm systems pick up strength when passing over warm water. They usually lose intensity over land, and also over cold water, (which is why hurricanes are no more than tropical storms when they get to Newfoundland.) This suggests that the strength of the storm system comes from sucking up warm water vapour rising by convection, whereas warm dry air rising from the land does not feed the system: they always lose strength over land. Warm air will rise, so dry warm air over land is creating some currents that might affect the motion of the system as suggested by the OP - I don't know how strong an effect that would be.

You can toggle between the water vapor loop and the RH (relative humidity) loop and see that they correspond, but you would think there would be a legend for the color scale.

It all makes sense now. The BROWN is dry air and that is what the meteorologists suggest keeps the storms from growing in intensity.

It just took me a little while to grasp the images. Thank you all, its why I always come here to this forum for my answers.

Lets hope the BROWN stays in place until the GOM itself cools down enough to not feed these monsters.