Overcast, wet and why leaves change color in the fall
This morning it is overcast with a chance of a thunderstorm and a chance of rain. High of 81F. Winds less than 5 mph. Chance of rain 50%.
Tonight it will be overcast with a chance of a thunderstorm and rain showers, then a chance of a thunderstorm and a chance of rain after midnight. Low of 64F. Winds from the South at 5 to 10 mph. Chance of rain 60% with rainfall amounts near 0.6 in. possible.
The readings from my own instruments are:
The humidity is 88% with a Dew Point of 66.1ºF and a wind chill of 69.8ºF.
The temperature Is 69.8ºF.
We have East Southeast winds barely puffing between 0.0 mph and 1.0 mph.
Our Barometric pressure is 29.73 HPA 1006.7 and falling with a weather graphic indicating rainn.
The UV rating is 0 out of 16, sunset will be at 7:16 PM with Moon Rise at 1:20 a.m. and the moon phase is waning crescent.
For the pilots out there, Raw Metar readings are:
METAR KAUG 311153Z AUTO 00000KT 7SM BKN003 BKN100 OVC110 18/18 A2982 RMK AO2 SLP097 60004 70051 T01830178 10183 20172 53005
Visibility is 7.0 miles/11.3 kilometers with mostly cloudy conditions between 300 ft / 91 m., and 10,000 ft / 3,048 m. and overcast to 11,000 ft / 3,352 m.
We've had 0.73 inches of rain here in the past 24 hours Around here, that came last night when the clouds opened up.
We're coming up on fall folks, so as we begin the run-up to leaf-peeping season you may ask yourself : "Why Do Leaves Change Color in the Fall?"
From Anne Marie Helmenstine, Ph.D., on About.com
Answer: When leaves appear green, it is because they contain an abundance of chlorophyll. There is so much chlorophyll in an active leaf that the green masks other pigment colors. Light regulates chlorophyll production, so as autumn days grow shorter, less chlorophyll is produced. The decomposition rate of chlorophyll remains constant, so the green color starts to fade from leaves.
At the same time, surging sugar concentrations cause increased production of anthocyanin pigments. Leaves containing primarily anthocyanins will appear red. Carotenoids are another class of pigments found in some leaves. Carotenoid production is not dependent on light, so levels aren't diminished by shortened days. Carotenoids can be orange, yellow, or red, but most of these pigments found in leaves are yellow. Leaves with good amounts of both anthocyanins and carotenoids will appear orange.
Leaves with carotenoids but little or no anthocyanin will appear yellow. In the absence of these pigments, other plant chemicals also can affect leaf color. An example includes tannins, which are responsible for the brownish color of some oak leaves.
Temperature affects the rate of chemical reactions, including those in leaves, so it plays a fpart in leaf color. However, it's mainly light levels that are responsible for fall foliage colors. Sunny autumn days are needed for the brightest color displays, since anthocyanins require light. Overcast days will lead to more yellows and browns.
Enjoy Fall Leaf Color
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