Watch, Warning & Advisory Criteria For NWS Morristown TN

Dangerous Heat in the Central and Eastern U.S.; Severe Thunderstorms in the Central U.S. and Northeast; Critical Fire Weather in the Four Corners

Dangerous, record-breaking heat will intensify across most of the central and eastern U.S this week. Heat indices will likely exceed 100 degrees. Severe thunderstorms are forecast from parts of the central High Plains into the Upper Midwest, and across parts of the Northeast. Critical fire weather conditions will continue across portions of the Four Corners and Great Basin. Read More >

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

Snow

1" to 3” in 12 hours*

Freezing Rain & Sleet

Ice accumulation < 0.25”

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

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

Extreme Heat Warning

Heat Advisory

Red Flag Warning

for TN/NC

Red Flag Warning

for VA

Cold Weather Products

Daytime Heat Index

> 110°F

Temperature

> 105°F

Daytime Heat Index

> 105°F

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%

See map and description of criteria below

Cold Weather Advisory and Extreme Cold Warning: Replaces Wind Chill Products October 1, 2024

*Based on wind chill values AND/OR actual air temperature

Dangerous Heat in the Central and Eastern U.S.; Severe Thunderstorms in the Central U.S. and Northeast; Critical Fire Weather in the Four Corners

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

WINTER WEATHER

NON-PRECIPITATION HAZARDS

NON-PRECIPITATION HAZARDS