How is MI used in a METAR report?

MI (Shallow) appears in the weather phenomena section of a METAR. Examples include: MIFG, MI FG, MIFG VV001. It falls under the "Descriptor" category.

What METAR codes are related to MI?

Codes related to MI (Shallow) include: FG (Fog), BC (Patches), PR (Partial). These are often seen together in METAR weather observations.

Descriptor

MI—Shallow

Q: What does MI mean in a METAR?

MI stands for "Shallow" in a METAR weather report. Indicates a weather phenomenon that extends only a short distance above the surface, generally less than 6 feet deep. Most commonly used with fog (MIFG) to describe shallow fog that obscures the runway surface but allows visibility above the fog layer. Shallow fog can make taxiing hazardous while flight visibility may be adequate.

METAR weather code reference for MI (Shallow)

What Does MI Mean?

Indicates a weather phenomenon that extends only a short distance above the surface, generally less than 6 feet deep. Most commonly used with fog (MIFG) to describe shallow fog that obscures the runway surface but allows visibility above the fog layer. Shallow fog can make taxiing hazardous while flight visibility may be adequate.

Examples in METAR Reports

Here are common ways MI appears in real METAR observations:

MIFG

MI FG

MIFG VV001

Related Codes

These METAR codes are commonly seen alongside MI or describe related weather phenomena:

Fog

A visible aggregate of microscopic water droplets suspended at the earth's surface that reduces visibility to less than 5/8 of a statute mile. Fog is one of the most common causes of IFR conditions and flight delays. When visibility improves above 5/8 mile, the observation changes from FG to BR (mist).

Patches

Describes a weather phenomenon occurring in irregular patches across the observation area rather than uniformly. Most commonly seen as BCFG (patches of fog), meaning fog covers some areas of the airport but not others. Patchy conditions can create unpredictable visibility changes during taxi, takeoff, and landing.

Partial

Indicates that the weather phenomenon covers a significant portion of the airport but not all of it. PRFG (partial fog) means fog obscures part of the airport, such as one end of the runway, while other areas remain clear. This can create significant challenges for approach and landing operations.

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