Thanks to another strong high pressure system bringing dry air and pleasant temperatures, we will enjoy awesome weather for outdoor activities this weekend.
As we head into Saturday evening, clear skies will prevail with light winds. Because of the dry air in place, our atmosphere will cool down quickly after sunset. As a result, expect chilly temperatures overnight with lows in the upper 40s to lower 50s.
Sunday will also have pleasantly warm temperatures with highs in the mid 80s under mostly sunny skies.
Sunday night into Monday, another batch of Gulf moisture will stream our way ahead of yet another cold front. This system will bring a decent chance of showers and thunderstorms as we head back to work and school next week.
Interestingly, an upper level low pressure system is expected to stall over the deep south next week. If this occurs, we will have a continued chance of showers and possible thunderstorms for much of next week. This would be great news for our drought situation.
Now, you may wonder, "what is a cut off low"? Well, this is a situation when a storm system becomes detached from the jet stream. The jet stream is a fast section of wind in our upper atmosphere. It is the dividing line between cold air masses and warm air masses. When a storm system remains a part of the jet stream pattern, the fast flowing winds of the jet stream keep the storm system moving along. This is illustrated by the following picture below. Notice the "U" shape in the black lines of this upper atmosphere chart. This "U" shape is called a Trough of Low Pressure. The entire flow pattern of blue color on this chart following the black lines from west to east, including the "U" shaped trough, is the jet stream.
As you will see on this next chart below, notice how the black lines become a circle over the Southern Plain States and the Lower Mississippi River Valley. This "circle", called an upper level low pressure system, is now detached from the main flow of the jet stream pattern. Since this upper level low pressure is going to become detached from the main flow of the jet stream, the upper level low will stall and sit over the deep south for the next few days.
As a result, this upper level low will keep our atmosphere unsettled bringing us an extended chance of scattered showers or thundershowers. As long as this upper level low pressure system remains stalled, or "cut-off" from the jet stream pattern, it will remain over the deep south with a continued chance of rain.
If this forecast does come true for us, it will be great news regarding our drought situation with the extended chance of rain for much of our work week beginning on Monday 10/22/07.
Stay with CBS 42 as we keep you up to date with the latest forecast.
1 comment:
Thank you for your explanation of an upper level low. I learned something new. You do an outstanding job teaching. Keep up the good work.
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