Northern Indiana Watch, Warning and Advisory Criteria

BLIZZARD

Potential for Sustained wind or frequent gusts > 35 mph and visibility ¼ mi < in S/BS for > 3 hrs in the next 12 to 48 hours

WINTER STORM WATCH

Sustained wind /frequent gusts > 35 mph and visibility < ¼ mile in snow/blowing snow for > 3 hours

BLIZZARD WARNING

NOT ISSUED

BLOWING DUST

NOT ISSUED

NOT ISSUED

Widespread visibility < ¼ mile

BLOWING SNOW

Address potential in HWO and other notification methods.

NOT ISSUED

Widespread visibility < ¼ mile

WINTER WEATHER ADVISORY

FIRE

Potential for ten hour fuels <= 8%, sustained winds >= 20 mph for 3 hours or more, RH <= 25% for 3 hours or more

FIRE WEATHER WATCH

ten hour fuels <= 8%, sustained winds >= 20 mph for 3 hours or more, RH <= 25% for 3 hours or more

RED FLAG WARNING

NOT ISSUED

FOG

NOT ISSUED

NOT ISSUED

Widespread visibility < ¼ mile

FREEZE

Potential for Temperatures < 32° F and  >= 29° F  between May 1 and October 20

FREEZE WATCH

Temperatures < 32° F and >= 29° F   between May 1 and October 20

FREEZE WARNING

NOT ISSUED

HARD FREEZE

Potential for Temperatures  < 28° F between May 1 and October 20

HARD FREEZE WATCH

Potential for Temperatures  < 28° F between May 1 and October 20

HARD FREEZE WARNING

FROST

Address potential in the HWO and other notification methods.

NOT ISSUED

Formation of frost between May 1 and October 20 (Temperatures less than or equal to 36).

FROST ADVISORY

FREEZING RAIN

Potential for freezing rain with significant /damaging ice accumulations (usually ≥ ¼")

WINTER STORM WATCH

Ice accumulation ≥ ¼" on all surfaces

ICE STORM WARNING

Light ice accrual generally  < ¼" of an inch on all surfaces

WINTER WEATHER ADVISORY

FREEZING FOG

Address potential in HWO and other notification methods.

Ice accrual covering all surfaces with ice accumulation < ¼"

Very light ice accumulation from freezing fog

HEAT INDEX

HI > 105° F and the minimum heat index of at least 75° F for a 48 hour period.

Consider a HI warning if Heat advisory conditions are met for 4 consecutive days

HI around 100° F and/or
Max temperature  > 95° F

ICE STORM

Potential within 24-72 hours for ice accums greater than or equal to 1/4 inch.     

WINTER STORM WATCH 

Ice accumulation greater than or equal to 1/4 inch with damage.
 

WINTER STORM WARNING

NOT ISSUED

SLEET

Sleet ≥ ½" accumulation

WINTER STORM WATCH

Sleet Accumulation > ½"

WINTER STORM WARNING

Sleet Accumulation < ½"

WINTER WEATHER ADVISORY

HEAVY SNOW

(also used for snow and blowing snow)

Snow accumulation ≥ 6" avg in 12 hrs
or ≥ 8" in 24 hrs

WINTER STORM WATCH

> 6 " in 12 hours
> 8 " in 24 hours

WINTER STORM WARNING

3 to 5 inches
2 to 4 inches(forecaster discretion)

WINTER WEATHER ADVISORY

LAKE EFFECT SNOW

(also used for lake effect snow and blowing snow)

Potential for snow

accumulation: ≥ 6" in 12 hrs or ≥ 8" in 24 hrs

LAKE EFFECT SNOW WATCH

Snow accumulation ≥ 6" avg in 12 hrs or ≥ 8" in 24 hrs

LAKE EFFECT SNOW WARNING

3 - 5 inches of lake effect snow in 12 hours (forecaster discretion 2 - 4 inches)

LAKE EFFECT SNOW ADVISORY

WIND

(HIGH WIND)

Sustained non-convective wind > 40 mph
or > 1 hour and/or gusts > 58 mph

HIGH WIND WATCH

Sustained non-convective wind > 40 mph for > 1 hour and/or gusts > 58 mph

HIGH WIND WARNING

Sustained non-convective wind between 30 and 39 mph for > 1 hour and/or gusts between 45 - 57 mph

WIND ADVISORY

WIND CHILL

Potential for WC ≤ -25° F

WIND CHILL WATCH

WC < -25° F

WIND CHILL WARNING

WC -15° F to -29° F

WIND CHILL ADVISORY

WINTER STORM

Potential for snow accumulation: ≥ 6" in 12 hrs or ≥ 8" in 24 hrs , Combination of Snow, Sleet and Freezing Rain Meeting Warning Criteria, and/or Blowing and Drifting Snow Approaching Blizzard Conditions; Mixed Precipitation (lesser amounts if mixed precipitation)

Wind Chill ≤ -25° F

WINTER STORM WATCH

Combination of any winter warning hazards, including significant blowing and drifting snow below blizzard conditions (lesser amounts may be warranted especially if significant mixed precipitation in an early or late season event)

 

WINTER STORM WARNING

WINTER WEATHER

Combination of any winter advisory hazards

WINTER WEATHER ADVISORY