WINTER WEATHER VERIFICATION STATISTICS
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Joe Dellicarpini, Storm Data/Storm Verification Program Leader
This section contains preliminary verification statistics for all winter storm and high wind watches, warnings, and advisories issued by NWS Taunton during the cool season (essentially October through May) for its County Warning Area.
Reports used in verification are typically received from trained Skywarn spotters, amateur radio operators, and law enforcement agencies. In some cases, reports from the media and public are also used. Verification for High Wind Warnings and Advisories is usually more difficult to obtain, since fewer spotters have access to reliable wind speed measurements. Automated stations such as ASOS (the Automated Surface Observing System, implemented at many airports nationwide as part of the NWS Modernization) are used heavily, and are supplemented by those spotters who have equipment approved by NWS Taunton.
The criteria used in verifying each type of Watch, Warning, or Advisory is as follows:
Winter Storm Watch/Warning: 7" or more of snow (or snow and sleet combined), or 0.5" or more accretion of freezing rain.
Warning: expected to occur within 24 hrs
Watch: may occur in 12-24 hrs
Winter Weather Advisory: Criteria varies slightly by state.
MA/CT/RI: 4,5, or 6" of snow in 24 hours
NH: 5 or 6" of snow in 24 hours.
Also for any accretion of freezing rain or freezing drizzle on road surfaces, a mix of snow and sleet totaling 4,5, or 6", or blowing/drifting snow occasionally reducing visibility to less than a quarter mile.
High Wind Warning: Sustained wind of 40-73 mph for at least one hour, or any gusts of 58 mph or greater.
Wind Advisory: Sustained wind of 31-39 mph for at least one hour, or any gusts of 46-57 mph.