Morristown, TN

Weather Forecast Office

Watch, Warning & Advisory Criteria For NWS Morristown TN

NWS Morristown TN - Advisory and Warning Criteria

The following are the criteria used by the National Weather Service office in Morristown, TN to issue Advisories & Warnings.

Watches are generally issued with longer lead times in expectation of meeting Advisory and/or Warning criteria.

SEVERE WEATHER

Severe Thunderstorm Warning

Tornado Warning

Hail

> 1.00”

AND/OR

Wind

> 58 mph (50kts)

AND/OR

Significant Wind Damage, i.e., Trees down, large tree limbs down, structural damage to buildings.

Tornado

A violently rotating column of air in contact with the ground,

indicated by either radar or report.

WINTER WEATHER

Winter Weather Advisory

Ice Storm Warning

Blizzard Warning

Wind Chill Warning

Wind Chill Advisory

Snow

1" to 3” in 12 hours*

OR

Freezing Rain & Sleet

Ice accumulation < 0.25”

OR

at the forecaster's discretion

Ice accumulation

> 0.25” in 12 hours

Visibility

< ¼ mile

AND

Sustained Winds or Frequent Gusts

> 35mph for at least 3 hours which is accompanied by either snow or blowing snow

Wind Chill

< -15°F

with Winds

>10 mph for at least 3 hours

Wind Chill

-5°F to -14°F

with Winds

> 10 mph for at least 3 hours

NON-PRECIPITATION HAZARDS

High Wind Warning

Wind Advisory

Dense Fog Advisory

Dense Smoke Advisory

Freeze Warning

Frost Advisory

Sustained Winds

> 40 mph for at least 1 hour

AND/OR

Wind Gusts

> 58 mph for any duration

Sustained Winds

26 to 39 mph for at least 1 hour

AND/OR

Wind Gusts

between 40 and 57 mph for any duration

Visibility

< ¼ mile over a large area

Visibility

< ¼ mile over a large area

Temperature

< 32° for areas still in Freeze program

Temperature

33° to 36° during defined growing season

NON-PRECIPITATION HAZARDS

Excessive Heat Warning

Heat Advisory

Red Flag Warning TN/NC

Red Flag Warning for VA

Daytime Heat Index

> 110°F

OR

Temperature

> 105°F

Daytime Heat Index

> 105°F

OR

Temperature

> 103°F

Sustained winds (2 minute average) > 18 mph

AND

relative humidities < 25%

AND

rainfall < 0.25" over the past 2 days.

Sustained winds (2 minute average) > 20 mph

AND

relative humidities < 30%

AND

10 hour fuel moisture observed or expected < 7%