I've Been Thunderstruck

I recently “discovered” on the local NWS website the Satellite Water Vapor Imagery data for our area, and I’m quite fascinated by it! The official description of this data is as follows:

Water vapor satellite imagery depicts moisture content in the middle and upper layers of the atmosphere. Lower level moisture is not depicted in these images. Moisture transport over large distances generally happens through the middle and upper layers of the atmosphere. Hence these images will depict moisture coming into the Southwest from the Gulf of Mexico or across Texas. Additionally, weak disturbances from the east are best tracked through water vapor imagery.

The imagery looks like this when viewed online. The is a screen capture of one frame of data:

Water Vapor Imagery

Basically, what this shows is the amount of moisture that is in the upper atmosphere. This may be in the form of clouds that you see, but often it is not. Water vapor literally surrounds the earth, but is unevenly distributed due to things like oceans, lakes, rivers, deserts, arid areas, etc. For instance, in the image above, you can see a lot of water vapor coming up from the southwest into places like Arizona and New Mexico, which are traditionally dry regions. Areas like the Pacific Northwest, which are usually wet, have much less than normal. This is all due to seasonal shifts in winds and weather patterns, which change the flow of moisture around the planet. By looking at an image like this, you can get an idea of how much moisture is available in your area…moisture that could turn to rain or snow!

When I drove to work this morning, around 9AM, the sky was almost perfectly clear.  A few high cirrus clouds, but nothing aside from that…just blue sky. Below is a snapshot from my phone on what the sky looked like around 1:30PM today:

Quick Storm Development

Since this picture was taken, our area has seen multiple Severe Thunderstorm alerts, along with several Flash Flood warnings! It absolutely amazes me how quickly the weather can turn in our area of the wood, and why it’s always important to keep an eye on weather when outside doing fun things. Dry washes and rivers can turn into raging torrents without a single drop falling in your particular area. Always know the weather!