Skew T

What is a skew-T diagram?

• Diagram used to plot vertical profiles through the atmosphere

• Determine atmospheric stability

WHAT MAKES UP A SKEW-T DIAGRAM ?

Isobars

• Horizontal lines • From 1050 hPa up to

100 hPa• Plotted every 50 hPa

Isotherms

• Lines of constant temperature

• Straight, solid lines from the lower left to upper right

Dry Adiabats

• Lines of constant potential temperature

• Solid, slightly curved lines sloping from the upper left to the lower right

• Rate of temperature change in a parcel of dry air rising/descending adiabatically

• (no loss or gain of heat by the parcel)

Saturation/Moist Adiabats

• Lines of constant equivalent potential temperature

• Curved dashed lines – slope and spacing varies with height and temperature

• Becomes parallel to dry adiabats as pressure moisture, and temperature decrease

ws = Mv / Md

Ratio of mass of water vapor to mass of dry air at saturation

Saturation Mixing Ratio

• Lines represent constant values of water vapor capacity

• Labeling of the lines is not uniform because vapor capacity of air varies non-linearly with temperature

A) ISOBARB) DRY ADIABATC) SATURATION ADIABARD) ISOTHERME) SATURATION MIXING-

RATIO

Wind

• Plain end of staff points in the direction that the wind is blowing toward

• Speed is plotted with barbs and flags:

flag = 50 knotsFull barb = 10 knotsHalf barb = 5 knots

55 kt250° / WSW

35 kt135° / SE