Northern Indiana Watch, Warning and Advisory Criteria

PARAMETER	WATCH	WARNING	ADVISORY
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