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Category Archives: Seasons
How do we measure an official snowfall for Madison?
Accurate and precise measurement of snow accumulation is a difficult task.
The measurement tools are simple: a ruler or yardstick that measures in inches and tenths of an inch. Continue reading
What forces a mid-latitude cyclone to develop?
Our storm on Wednesday night and Thursday of last week was the first strong storm of the autumn/winter season. As you found yourself caught in the strong winds, you may well have wondered how do storms like this one come to be.
That has been the central motivating question in meteorological science for most of the past 100 years. Continue reading
Why are cold snaps in autumn so short-lived?
Over the past weekend, southern Wisconsin experienced its first cold snap of the season with widespread morning lows in the upper 20s on Friday and Saturday mornings.
Often, cold snaps in autumn are short-lived, as this recent example was, affecting usually one or two nights at most. Continue reading
What does El Nino mean for southern Wisconsin’s winter this year?
El Nino is an atmosphere/ocean phenomenon in which the waters of the eastern equatorial Pacific Ocean are warmer than normal for an extended period of time.
This unusual warmth forces changes in the distribution of deep convective thunderstorms over the tropical ocean which, in turn, affect the position and strength of the jet stream. Since the jet stream acts a conduit of winter storms and can regulate intrusions of cold arctic air, changes in jet stream characteristics can have a profound influence on our winter weather. Continue reading
Category: Meteorology, Phenomena, Seasons
Comments Off on What does El Nino mean for southern Wisconsin’s winter this year?
Comments Off on What does El Nino mean for southern Wisconsin’s winter this year?
When is the autumnal equinox?
On Wednesday morning, we will officially enter fall as the autumnal equinox occurs at 3:20 a.m.
On Wednesday, in common with every location on Earth, we will enjoy exactly 12 hours of daylight and 12 hours of night.
Of course, 12 hours of daylight in Madison (latitude 43N) is substantially different from 12 hours of daylight at the North Pole (latitude 90N) where the sun will barely be visible above the horizon for the 12 hours of “daylight.” On the very next day, the sun will not appear above the horizon at the Pole and will not come back for six months. As the days march on, the same fate will gradually overtake other latitudes in the Northern Hemisphere until by Dec. 21, the sun will not rise even at 66.5N. Continue reading
