Weather Issues

Weather Advisories and Warnings - Descriptions

TYPE OF ISSUANCE WHEN ISSUED FOR SOUTHERN NEW ENGLAND

WINTER WEATHER ADVISORY
When the following expected in the next 24-36 hours:
Any accretion of freezing rain or freezing drizzle on road surfaces
Blowing/drifting snow occasionally reducing visibility to <= 1/4 mile
Snow or snow and sleet combination:
3, 4, or 5 inches averaged over a CT, MA, RI forecast zone in 12 hours.
4 or 5 inches averaged over a NH forecast zone in 12 hours

WINTER STORM WARNING
When the following expected in the next 24-36 hours:
1/2 inch accretion of freezing rain in any zone
Snow or snow and sleet combination:
6 inches averaged over a forecast zone in 12 hours
8 inches averaged over a CT, MA, RI forecast zone in 24 hours.
9 inches averaged over a NH forecast zone in 24 hours

BLIZZARD WARNING
At least 3 hours, falling and/or blowing snow frequently reduces visibility to < 1/4 mile AND sustained winds or frequent gusts >= 35 mph

WIND CHILL ADVISORY
Wind chill index between -15F and -24F for at least 3 hours using only the sustained wind (except -20F to -29F southern NH)

WIND CHILL WARNING
Wind chill index<= -25F for at least 3 hours using only sustained wind (except -30F southern NH)

WIND ADVISORY
Sustained winds 31-39 mph (27-34 kts) for at least 1 hour; OR any gusts to 46-57 mph (40-49 kts)

HIGH WIND WARNING
Sustained winds 40-73 mph (>= for at least 1 hour; OR any gusts >= 58 mph (>= 50 kts)

INLAND HIGH WIND WARNING FOR HURRICANE FORCE WINDS
Sustained winds >= 74 mph

DENSE FOG ADVISORY
Widespread visibility <= 1/4 mile for at least 3 hours

SMALL CRAFT ADVISORY
Sustained wind 25-33 knots AND/OR Seas >= 5 feet within 12 hours

GALE WARNING
Sustained wind 34-47 knots within 24 hours from a non-tropical system

STORM WARNING
Sustained wind >= 48 knots within 24 hours from a non-tropical system

TROPICAL STORM WARNING
Sustained winds of 39-73 mph (34-63 knots) within 24 hours

HURRICANE WARNING
Sustained winds >= 74 mph (64 knots) within 24 hours; implies dangerous storm surge

SPECIAL MARINE WARNING
Brief/sudden occurrence of sustained wind or frequent gusts >= 34 knots, usually associated with thunderstorms; also issued for waterspouts

SEVERE THUNDERSTORM WARNING
Thunderstorms with wind gusts >= 58 mph AND/OR hail >= 3/4" in diameter

TORNADO WARNING
Likelihood of a tornado within the given area based on radar or actual sighting; usually accompanied by conditions indicated above for "Severe Thunderstorm Warning"

FLASH FLOOD WARNING
A flood that occurs within a few hours of heavy rainfall, a dam or levee failure, or water released from an ice jam

FLOOD WARNING
Expected inundation of a normally dry area near a stream or other watercourse; OR unusually severe ponding of water expected

RIVER FLOOD WARNING
Expected flooding of main stem rivers (such as the Merrimack, Charles, Connecticut, etc.)

COASTAL FLOOD WARNING
Widespread coastal flooding expected within 12 hours; more than just typical overwash.