supercells: labeling (as viewed from the se) the...
TRANSCRIPT
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)
- 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?
The shear in the environmental winds provides a source of background rotation. (Think of rolling a pencil between your two hands....)
shear in the environment
The end result is an environment favorable for tornado formation (Roughly 20-25% of supercells produce tornadoes.)
a rotating wall cloud at the base of a supercell updraft
and another, this time with tornado
this one also had a tornado, shortly before the (clearly photoshopped) picture was snapped
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.
Conditions for the April 15, 2011 Tornado Outbreak
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
Frequency of tornado occurrence(average number per year by state)
Where are tornadoes most likely?
Number of tornadoes by month in the US
What time of year are tornadoes most likely?
Number of tornadoes by time of day in the US
What time of day are tornadoes most likely?
● 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
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)