Watches

Flash Flood Watch: [FF.A]

• Potential for flash flooding due to non-convective causes (e.g., dam or levee failure or ice jam), or the possibility of flash flooding and debris flows caused by excessive rainfall on burn scars or in debris flow- and landslide-prone areas.

Flood Watch: [FA.A]

• Conditions are favorable for flooding caused by excessive rainfall and runoff. As of 2021, this combines what was formerly (convective) Flash Flood Watches and Areal Flood Watches.

River Flood Watch: [FL.A]

• Issued for river forecast points when river flooding is possible, but flooding is not expected to begin within the next 24 hours.

Warnings

Flash Flood Warning: [FF.W]

• Short duration (usually less than six hours), flash flooding resulting from storms with rainfall rates of 1 to 2 inches per hour or greater. Also issued when a dam has failed or when a dam failure is imminent.

(Areal) Flood Warning: [FA.W]

• Long duration (slow to evolve), flooding resulting from steady stratiform rain with rates typically less than 1 inch per hour. Most common during long duration spring rains resulting in widespread flooding.

River Flood Warning: [FL.W]

• River flooding is occurring or is forecast for a point. Normally issued when flooding is forecast within 24 hours based on accumulated rainfall.

Advisories

Flood Advisory: [FA.Y]

• Localized flooding resulting from heavy rain. Water may start to threaten homes and businesses, and minor flooding of roads is possible

Watches

Winter Storm Watch: [WS.A]

• Potential for a blizzard, heavy snowfall, or ice storm within the next 18 to 48 hours. Issued when there is a 50% confidence or greater of at least 6 inches of snow and/or a ¼ inch of ice.

Extreme Cold Watch: [EC.A]

• Potential for reach Extreme Cold Warning criteria (see below) within the next 18 to 48 hours.

Warnings

Winter Storm Warning: [WS.W]

• Snow accumulations 6 inches or greater; Freezing rain accumulations ¼ inch or greater.

Blizzard Warning: [BZ.W]

• Sustained winds 35 mph or greater AND falling/blowing snow reducing visibility to less than ¼ mile for at least three hours.

Ice Storm Warning: [IS.W]

• Freezing rain accumulations ¼ inch or greater resulting in significant, widespread power outages, tree damage, and dangerous travel.

Lake Effect Snow Warning: [LE.W]

• Lake effect snow accumulations 6 inches or greater in 12 hours (8 inches or more in 24 hours). This is issued only for northernmost portions of our area.

Snow Squall Warning: [SQ.W]

• A short-duration (less than 1 hour), polygon-based warning issued when strong snow squalls and flash freezing will cause dangerous and life-threatening conditions, especially for roadways. Usually issued when ground/road temperatures are sub-freezing and visibility is less than ¼ mile.

Extreme Cold Warning: [EC.W]

• Lowest of either air temperature or wind chill that is -20ºF (-25ºF for Mercer/Venango/Forest Counties) or colder with wind speeds 5 mph or greater for at least 3 hours.

Advisories

Winter Weather Advisory: [WS.Y]

• Snow accumulations of 3 inches, any freezing rain accumulations less than ¼ inch, or a high impact snow/ice event.

Cold Weather Advisory: [CW.Y]

• Lowest of either air temperature or wind chill that is -10ºF to -20ºF (-15ºF to -25ºF for Mercer/Venango/Forest Counties) for at least 3 hours.

Watches

High Wind Watch: [HW.A]

• Conditions are favorable for development of sustained winds of 40 mph or greater and/or gusts of 58 mph or greater within the next 24 to 48 hours.

Freeze Watch: [FZ.A]

• Potential for the first freeze of the fall season or for a late spring freeze within the next 18 to 24 hours. Product is discontinued for the season following the first fall "killing" freeze.

Excessive Heat Watch: [HT.A]

• Potential for heat index values of 105ºF or hotter within the next 24 to 48 hours.

Warnings

High Wind Warning: [HW.W]

• Non-convective sustained wind speeds 40 mph and greater and/or wind gusts 58 mph and greater.

Freeze Warning: [FZ.W]

• When temperatures will be at or below 32ºF over a large area for a significant time during the growing season.

Excessive Heat Warning: [HT.W]

• Heat Index of 105ºF or greater.

Red Flag/ Fire Weather Warning: [FW.W]

• Dangerous fire behavior expected within the next 12-24 hours based on weather conditions and dry fuels.

Advisories

Wind Advisory: [WI.Y]

• Non-convective sustained wind speeds 30-39 mph with wind gusts 46-57 mph.

Frost Advisory: [FR.Y]

• When frost is expected during the growing season.

Heat Advisory: [HY.Y]

• Heat Index of 100ºF to 104ºF.

Dense Fog Advisory: [FG.Y]

• Fog reducing visibilities to a ¼ mile (0.4 km) or less for at least 3 hours.