December 08, 2018 09:21 PM
They can offer some relief from the heat on a sunny day, they can trap in heat overnight... they can also ruin a forecast. What are we talking about? Clouds. They're a tricky part of the forecast to forecast as there's many different parameters meteorologists can look at to possibly determine whether or not clouds will be in the forecast.
One way that meteorologists can look is by looking at the current water vapor in the low, mid and upper levels. Since clouds are made of moisture and satellite and radar loops show the current status of the atmosphere, meteorologists often look at these to first to build their forecast. Meteorologists will also look at the low, mid and upper levels individually to see if there's any moisture forecasted to move in (or out) by different models. Layers that are a bit more important than others to look at include the 700 mb layer (about 10,000 feet above the surface) and the 850 mb layer (about 5,000 feet above the surface). Particularly, the 850 mb layer is a good layer to look at if there's low level moisture advecting, or moving, into/out of a forecast area. This layer is also one that meteorologists look at to see whether a warmer or cooler airmass is moving in.
Another parameter than meteorologists look for is an inversion. Mostly limited to the lower layers of the atmosphere, an inversion, whether it's big and apparent or small and hidden, can help keep low level clouds. In short, an inversion is when there's warmer air above a layer in the atmosphere and the air in layer 1 can't lift into layer 2, so it "stays put" and remains condensed. That's what has been occurring over the ABC 6 forecast area; Saturday there was a small inversion just above the surface and the inversion may continue to linger into the day on Sunday.
Warmer air is continuing to make its way northwards from the southwest at 850 mb. The air in layers of the atmosphere beneath 850 mb can't lift upwards... so clouds may continue to remain. The only thing that would help open up the skies is if we can get some drier air to mix downwards and dry up the lower levels but with light, southerly winds... it may not be possible.
Updated: December 08, 2018 09:21 PM
Created: December 08, 2018 09:20 PM
Copyright 2018 - KAAL-TV, LLC A Hubbard Broadcasting Company