Here's a method I use and it involves the program called BUFKIT. The easiest way is to look at the overview of relative humidity the model forecasts over time. Here's an example of the GFS:
Read this from right to left which starts with this morning. Relative humidity values at lower levels according to the GFS computer model increases from Sunday through next week. Upper level moisture really ramps up from Monday through early next week too. Just at a quick glance, the cloudiest weather is going to be on Monday. We'll see a lot more puffy clouds in our future and even some mid and high level clouds too.
Clouds form at different layers of the atmosphere. If you have moisture at upper levels of the atmosphere you might see cirrus clouds develop. If there is a lot of moisture at low levels, you'll probably see more cumulus clouds or even stratus. So it's important to examine moisture at all levels of the atmosphere to get a clue as to the types of clouds that may form on a particular day and just how thick they might become.
Here's a basic cloud chart:
To help understand basic cloud formation, let’s take a look at a patch of land at sunrise.
- In the morning, the land is relatively cool.
- The sun begins to heat up the ground, and throughout the day, the ground becomes warmer and warmer.
- Certain areas of the ground may begin to heat up more quickly than others due to the terrain or surrounding conditions (for example, bare soil heats up more quickly than vegetation). When this happens, a thermal (also known as an updraft) can form. A thermal can be thought of as a rising “blob” of warm air due to unequal heating of the earth’s surface.
- When the thermal forms at the surface, it is warmer than the surrounding air. Warm air has a tendency to rise while cold air sinks, and since the thermal is warmer than the air around it, the air in the thermal will rise.
- As it rises, it will begin to expand and cool, and will continue to do so until its temperature is the same as the surrounding air temperature.
The lifting mechanisms associated with cloud development are:
* Surface heating and free convection
* Convergence of surface air
* Uplift along fronts
* Convection (thermal development)
The cloud formation process has already started today, actually it began only a few hours after sunrise once the land heated up and there is enough moisture at low levels for fair weather cumulus clouds to form. Based on the forecast model above, I expect a repeat performance tomorrow.
Hope this helps give you an idea as to how some meteorologists might forecast clouds.
Have a great day!
If you have any additional questions, feel free to contact me via Twitter: @jillgilardi, www.facebook.com/JillGilardiMeteorologist or email: firstname.lastname@example.org.
Jill Gilardi Fox 6 Meteorologist