1. Stratocumulus Regime
Extremely shallow moist layer and extreme capping; no mechanism to remove the cap; large scale subsidence strengthens the cap

2. Trade Wind Regime
Moist layer a little deeper, but very dry aloft; no mechanism to remove the cap.

3. Indo/Pacific Warm Pool
Marginally conditionally unstable through depth of troposphere. LCL low. Warm moist sfc air can get above LCL and have slight buoyancy to great heights, deep clouds, but relatively weak updrafts.

4. Indo/Pacific Warm Pool
Can’t generate large buoyancy—get weak vertical velocity
Marginally conditionally unstable through depth of troposphere. LCL low. Warm moist sfc air can get above LCL and have slight buoyancy to great heights, deep clouds, but relatively weak updrafts.

5. Oceanic sounding: at Gan in AMIE
Undiluted parcel

6. Jordan’s (1958) mean sounding for the West Indies
West Pacific
Similar to
Plot from Montgomery et al. 2006

7. “Hot Tower” Hypothesis
Riehl & Malkus 1958

8. What’s going on here?
Theta-e is reduced by entrainment in low levels, but fusion heating restores it back to PBL values in upper troposphere
The famous Riehl & Malkus “undilute hot tower” sounding,
Undilute ascent—classical assumption

9. Global Lightning Occurrence
Many deep Cb over tropical oceans have extensive glaciated anvils but do NOT exhibit lightning & thunder.
Christian et al. 2002

10. Updrafts in 100’s of aircraft penetrations of convective updrafts
Continental
flights
Ocean flights
Why?
T profiles?
Entrainment?
Zipser and Lutz 1994

11. West African Squall Line
No cap whatsoever. Very unstable all levels. LCL and LFC are elevated because air dry at lower levels. Once air gets above LFC, it can have very large buoyancy, strong updrafts, graupel, hail, lightning.

12. Continental sounding: West African Squall Line
Can generate huge T-Td
large w at low-mid levels
 super cooled water, graupel, lightning
~10°
No cap whatsoever. Very unstable all levels. LCL and LFC are elevated because air dry at lower levels. Once air gets above LFC, it can have very large buoyancy, strong updrafts, graupel, hail, lightning.

13. Tornado Soundings

14. Oklahoma Severe Thunderstorm
Extremely CU both above and below the cap. Cap is not so extreme that it can’t be removed by trough or front. Moderately moist aloft, so easily saturated.

15. Average Oklahoma Tornado Sounding
Fawbush and Miller 1951

16. Development of an Oklahoma Tornado Sounding
Cools
Warms
Lifting removes the negative area
Moist Adiabat
Newton 1963

17. Hurricane Soundings

18. Hurricane Erin (2001)
Halverson et al.

19. Hurricane Soundings and Jordan Sounding
Sheets 1969