Good morning everyone,
The day begins with fog and low clouds across all of Kansas City this morning Low clouds that spread across the sky are called stratus clouds. Fog is a stratus cloud that is on the ground. You can see the extensive low clouds on the 2-4 satellite picture that can be seen at this link: The 2-4 Satellite picture Here is an explanation of the shortwave minus long wave IR:
- Shortwave minus longwave IR:
Shortwave IR images only scratched the surface of the importance of the shortwave IR channel data. It was stated that the shortwave IR channel is sensitive to both reflected AND emitted IR energy at about 3.9 microns. While the sun is illuminating clouds, a very large portion of the measurements MAY be contributed by reflected energy. I use the word may because it depends on many things. The amount of reflected energy depends upon the relative angle between the sun, clouds, and satellite. It also depends upon the reflecting material: ocean, land, sandy deserts, snow-covered ground, ice particles and water droplets in clouds. It is these last 3 items which we care about most. These data have potential to discriminate clouds composed of water versus those composed of ice particles. A general rule of thumb: clouds composed of water REFLECT much more shortwave IR energy than clouds composed of ice or snow-covered ground. The amount of reflection is dependent upon the size of the water drops and ice particles. At night, reflection is not contributing to the measurements and any differences between water and ice/snow are purely emission. The water drops EMIT less energy at 3.9 microns than at 11 microns whereas ice particles EMIT nearly the same amount at the two wavelengths. Therefore subtracting the shortwave IR data from the longwave IR data produces negative values for clouds composed of water and near-zero values for ice/snow clouds. So what? Well, if you work on aircraft icing problems like we do, this data can be a goldmine. These data are also useful in detecting low stratus clouds and fog.
The dark colors show where the low clouds are located and the KC KSHB-TV viewing area is pretty much all encompassed by these clouds.
Kansas City Weather Time-Line:
- This morning: Cloudy with fog. The stratus deck will stay thick through around noon. Temperatures near 50°
- This afternoon: A south breeze increasing to around 10-15 mph will help move the clouds north and the sun should “burn” them off. The sun should come out with a high around 71°
- Friday: Mostly sunny and becoming humid with south winds 10-25 mph. High: 83°
- Saturday: Periods of clouds with a chance of thunderstorms. The chance is 20% during the morning increasing to a 90% chance during the late afternoon or evening. High: 81°
- Sunday: Decreasing clouds with northwest winds 10-20 mph and decreasing by evening. Dry for the Kansas City Chiefs and Sporting KC games. High: 60°
There has been a trend on all of the models for the storm moving across the middle of the nation on Saturday to just zip by very quickly. This map above shows this trend well. The cold front will have already passed KC by around 6 or 7 PM and it would be moving fast. This would limit the chance of thunderstorms to a short window from 4 PM to 8 PM with the severe weather risk a bit lower due to the surface low forecast to be way up in Wisconsin. Let’s see if these models continue this trend today.
We will look into the pattern and the thunderstorm risk in tomorrows blog and on 41 Action News tonight. Thank you for sharing in this weather experience and let us know if you have any questions. Go to the Weather2020 blog to join in the conversation.