Model Parameter Guide

Forecast air temperature about 6 feet above the ground.

The warmest or coldest temperature over the previous 24 hours.

How the air feels once wind or humidity is factored in.

How much moisture is in the air near the ground.

How close the air near the ground is to saturation.

A combined measure of the air's heat and moisture.

Surface pressure with high and low centers, isobars and wind.

The strongest expected short bursts of wind.

Rain, snow, sleet, or freezing rain, and how hard it is falling.

Liquid precipitation expected over a chosen window.

What the model expects radar to look like.

How much of the sky each cloud layer covers — low, middle and high.

How much of the sky is clouded over when every layer is added together.

Total moisture in the air column.

How far you can see near the ground.

How unusual temperature or moisture is compared with normal.

What an infrared satellite image could look like at the forecast time.

The total amount of smoke in the atmospheric column above a location.

The modeled concentration of smoke close to the ground.

Snow total assuming every inch of liquid makes 10 inches of snow.

Snow total using a temperature-based snow ratio.

How much the snow on the ground grows from the start of the run.

Model estimate of snow on the ground.

Freezing rain totals, as raw liquid or as estimated ice on surfaces.

The warmest temperature in the lower atmosphere, and the matching snow ratio.

The model’s estimate of lightning activity per unit area, averaged over a forecast interval.

Energy available to rising air.

The cap — energy holding rising air back.

A quick instability check comparing a rising parcel with the air at about 18,000 ft.

Height of cloud bases for rising surface air.

How fast temperature drops with height.

Change in wind from the surface to about 20,000 feet.

Rotation potential in the lowest 3 km.

Combines instability, shear and helicity into one supercell index.

Multiplies CAPE by helicity.

Instability shading with small wind-profile plots across the map.

Compares low-level and upper-level wind directions.

Simulated radar with rotating-storm tracks overlaid — only on convection-allowing models.

The pattern of ridges, troughs and wind at a chosen level.

Location and strength of the jet stream.

How much 500 mb heights rise or fall over 12 hours.

Air temperature above the ground at a chosen level.

How unusual heights or temperatures aloft are versus normal.

How moist the air is at a chosen level.

Low-level moisture above the ground.

Spin in the flow at a chosen level.

Where air is rising or sinking.

Warm or cold air being blown into an area.

Where temperature contrasts are tightening.

The height of the tropopause, shown as pressure or temperature.

How warm or cold the lower half of the atmosphere is.

A combined index of CAPE, shear, SRH, and LCL height.

Rotating storm updrafts simulated by high-resolution models.

A vertical slice of temperature, moisture, and wind at one point.

Average of all ensemble members.

How much members disagree, or the chance of exceeding a threshold.