General changes to BMJ convection (1 of 2)

• Triggering of deep and shallow convection

  • Integrated buoyancy (“CAPE”) >0 throughout parcel ascent, including below cloud base
    • “CAPE” ≡ ∫ B dp (B = parcel buoyancy)
    • B = (T+0.61qv-qt)parcel/(T+0.61qv)env – 1 (T = temperature, qv = vapor, qt = condensate)
  • Above criterion applied to all levels in the lowest 40% (was 20%) of atmosphere (p ≥ 0.6psfc; was ≥ 0.8psfc)
  • Most unstable parcel (MAP) => largest CAPE; MAP was the (θe)max , but intervening dry, stable layers could shift greatest parcel instability to higher levels (e.g., elevated CU decoupled from PBL)