National Weather Service Weather Forecast Office

THUNDERSTORM EVENTS

THRESHOLDS

SEVERE THUNDERSTORM WARNING - SVR

Winds of 50 kts (or implied by damage), and/or hail 3/4 inch (size of a dime)

TORNADO WARNING - TOR

Spotter report and/or radar indicated a tornado

FLASH FLOOD WARNING - FFW

Life/property threat within 6 hrs

FLOOD WARNING - FLW

Life/property threat beyond 6 hrs

FLOOD STATEMENT- FLS

Inconvenience flooding (urban and small stream flooding)

MARINE WEATHER

THRESHOLDS

SPECIAL MARINE WARNING - SMW

Tstm winds of 34 kts for 2 hrs; marine weather stmnt (mws) is issued for thunderstorm winds < 34 kts

GALE WARNING - ARBGLFLS (NSH)

Sustained winds 34 to 47 kts for many hours

STORM WARNING - ARBGLFLS (NSH)

Sustained winds of at least 48 kts

LAKESHORE WARNING - (CFW)

Significant lakeshore flooding, erosion, ice jam, or a seiche

SMALL CRAFT ADVISORY - (NSH)

Average Winds and/or frequent gusts of 22-33 kts and/or average waves of 4 ft

COLD-SEASON WEATHER

THRESHOLDS

WINTER STORM WARNING - WSW

Winter storm with more than one predominant hazard- heavy snow 6" or more within 12 hrs, or 8" or more within 24 hrs, or combination of wind-driven snow, sleet and/or freezing rain (1 pcpn type must meet warning criteria)

HEAVY SNOW WARNING- WSW

Heavy snow 6" or more within 12 hours or 8 “ or more Within 24 hours

LAKE EFFECT SNOW WARNING - WSW

Lake-effect snow of 6" or more within 12 hrs, or 8" or more within 24 hrs

BLIZZARD WARNING - WSW

Sustained winds or frequent gusts $ 35 mph and falling or blowing snow with visibilities < 1/4 mile for $ 3 hrs (only blowing snow for ground blizzard)

SLEET WARNING - WSW

Sleet accumulations $ 1/2 inch

ICE STORM WARNING - WSW

Ice accumulations $ 1/4 inch

WIND CHILL WARNING - WSW

Wind chills < -40 with winds > 10 mph

WINTER WEATHER ADVISORY - WSW

More than one predominant hazard- snow, sleet, freezing rain/drizzle; at least one hazard must meet advisory criteria

SNOW ADVISORY - WSW

Widespread snowfall >3 “ to 5" within 12 hrs or 5" to 7" within 24 hrs

LAKE EFFECT SNOW ADVISORY - WSW

Lake-effect snow - 3" to 5" in 12 hrs or 5" to 7" in 24 hrs

SLEET ADVISORY- WSW

Sleet accumulates < 1/2 inch

FREEZING RAIN ADVISORY - WSW FREEZING DRIZZLE ADVISORY - WSW

Light freezing rain or freezing drizzle With ice accumulations < 1/4 inch

WIND CHILL ADVISORY - WSW

Wind chills # -25 with winds > 10 mph

BLOWING SNOW ADVISORY - WSW

Wind driven snow, visibilities occasionally # 1/4 mile

LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY- WSW

Wind or gusts 25-34 mph with falling and blowing lake effect snow; Vsbys occasionally 1/4 mile

SNOW AND BLOWING SNOW ADVISORY- WSW

Wind or gusts 25-34 mph with falling and blowing snow; vsbys occasionally 1/4 mile

FREEZING FOG ADVISORY- NPW

Dense fog with freezing temps

NON-PRECIP EVENTS

THRESHOLDS

HIGH WIND WARNING - NPW

Sustained winds $ 40 mph for 1 hr or more, or gusts $ 58 mph

EXCESSIVE HEAT WARNING - NPW

During a 24 hour period, heat index $ 115 daytime for $ 3 hrs and $ 80 nighttime

FREEZE WARNING- NPW

In growing season, generally temperatures # 32 f

AIR STAGNATION ADVISORY - NPW

Major buildup of air pollution, smoke, dust, gases

CIVIL EMERGENCY- CEM

Nuclear or other hazardous materials emergency; Issued at the request of emergency management, sheriff

WIND ADVISORY - NPW

Widespread sustained winds $ 30 mph for 1 hr or more, Or gusts 45 to 57 mph

HEAT ADVISORY - NPW

During a 24 hour period, heat index = 105-114 daytime and $ 80 at night

DENSE FOG ADVISORY/DENSE SMOKE ADVISORY - NPW

Visibilities < 1/4 mile for 2 or more hours in dense fog/dense smoke

FROST ADVISORY - NPW

In growing season, light wind, clear skies plus widespread temperatures of 35F or less

FREEZING FOG ADVISORY - NPW

Ice accumulation from predominantly freezing fog.

FIRE WEATHER

THRESHOLDS

RED FLAG WARNING- MN

1-MIN WIND of 25 mph, MIN RH < 25% and TEMPS of 75F

RED FLAG WARNING- WI

1-MIN WIND of 25 mph, MIN RH < 25% and TEMPS of 75F and Critically dry fuels