SKEW T Pt. 2 Calculations and Indicies 330 Final Exam

Define an index

Shortcuts and estimates

why should you be careful using indexes

they dont show the entire picture

the lcl is where a parcel

becomes saturated (RH = 100%) and clouds beging to form

How to find the LCL

indentify the temp and td of your starting level, Follow DA up from temp, follow MRL from Td, point where these two cross = LCL

For LI you start at the __ and for SSI you start at

surface, 850mb

Find the lifted index (LI)

From lcl, follow the mA up to 500mb, red the temp of the parcel, indentify the actual temp of the env a 500, LI = T500 - Tp

Calculate the SSI

Follow the MA from the LCL up to 500, red parcel temp at 500, S = T500 - Tp

if the LI or SSI is ___ there is a possibility of severe WX (very unstable)

< -6

CAPE meaning

convective availiable potential energy

CAPE definition

the positive area between the parcel path and the environmental air

How do we measure cape

from the Level fo free convection (LFC) to the equilibruim level (EL).

higher values of CAPE mean

stronger convection >1000J/kg = severe wx

CIN meaning

convective inhibition / negative cape

CIN acts as a

cap to limit storm potential

0-20 j/kg is a

weak cap

21-50 j/kg is a

mod cap

51-99 j/kg is a

strong cap

LFC

level where a parcel first gains positive buoyancy.

LFC only exists when

the parcel become warmer than its environment

How to determine LFC

lift the parcel starting dry, then moist after LCL). the LFC is where Tp line crosses to the right of the T ENV temp profile.

The EL is

point where the parcel is no longer buoyant bc its temp is now less than the evironmental temp (T parcel < T env)

How to determine the EL

Continue following the MA upward from the LFC. the EL is where the parcel line crosses back to the left of the environmental profile.

how to find CCL = convective condensation level

Find surface Td, follow MRL up till it itersects w the T ENV

Tc is (convective temp)

the surface temp required for clouds to form due to heating alone. if reached, CIN bvecomes 0.

How to find Tc

from ccl follow the DA back down to surface pressure.