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Weather Question

PostPosted: Sun Sep 16, 2018 12:59 pm
by Perry
How does the dew point increase rapidly when there's not much wind bringing in new air? Where is all that water coming from? Sprinklers and grass? This happened today and last Sunday. ... m=72&raw=0

Date(PDT) Temp (F) Dew Point (F) Relative Humidity(%) Wind Direction Wind Speed(MPH) Visibility(miles) Clouds Station Pressure(inches) Sea Level Pressure (mb) Altimeter Setting (inches)
16 Sep 10:53 am 93 66 41 _ _____ 10.00 CLR 29.43 1011.0 29.87
16 Sep _9:53 am 91 55 30 N CALM 10.00 CLR 29.43 1011.1 29.87
16 Sep _8:53 am 90 39 17 N CALM 10.00 CLR 29.42 1010.7 29.86

Re: Weather Question

PostPosted: Sun Sep 16, 2018 2:24 pm
by zippetydude
Here's a graph of the last 7 days:


You raise an interesting question. It seems that sometimes the dew point and relative humidity spike somewhere shortly after sunrise, which would lead me to believe that the sun was adding sufficient energy to the condensed water on the surface to cause it to evaporate and add moisture to the air. But this only seems to happen about half of the time, with the opposite happening just after sunrise on other days...?