Supercells: Labeling (as viewed from the SE) the...
Transcript of Supercells: Labeling (as viewed from the SE) the...
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front-flank downdraft
rear-flank downdraft
front-flank gust front
rear-flank gust front
rotating updraft
upper-levelwinds overhanging
anvil
Supercells: Labelingthe Parts
(as viewed from the SE)
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- Remember: supercells form in high-shear environments
The Supercell Updraft and Tornadoes
When a tornado forms, it's usually part of the supercell's rotating updraft. So why does the updraft rotate in the first place?
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The shear in the environmental winds provides a source of background rotation. (Think of rolling a pencil between your two hands....)
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shear in the environment
The end result is an environment favorable for tornado formation (Roughly 20-25% of supercells produce tornadoes.)
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a rotating wall cloud at the base of a supercell updraft
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and another, this time with tornado
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this one also had a tornado, shortly before the (clearly photoshopped) picture was snapped
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Favorable supercell conditions (and storm conditions in general) are when warm, humid air off the Gulf is drawn northward below an upper-level disturbance with strong shear, often as part of a developing cyclone.
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Conditions for the April 15, 2011 Tornado Outbreak
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EF0
EF1
EF2
EF3
EF4
EF5
64-85 mph
86-110 mph
111-135 mph
136-165 mph
166-200 mph
> 200 mph
The Enhanced Fujita (EF) Damage Scale
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Frequency of tornado occurrence(average number per year by state)
Where are tornadoes most likely?
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Number of tornadoes by month in the US
What time of year are tornadoes most likely?
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Number of tornadoes by time of day in the US
What time of day are tornadoes most likely?
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● Finally, large collections of individual storms (including any of the three types) often organize themselves into much larger systems, called mesoscale convective systems (MCS)
● The classic MCS types include:
● Squall lines usually form form in environments with significant shear
Collections of Storms
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Collections of Storms
● MCCs tend to form in environments with weaker shear
● The classic MCS types include:
● Finally, large collections of individual storms (including any of the three types) often organize themselves into much larger systems, called mesoscale convective systems (MCS)