National Weather Service United States Department of Commerce

Strong Bering Storm Impacting Portions of Alaska; Critical Fire Weather Conditions in the Great Basin and Northern Rockies

A strong Bering Sea storm will continue to impact the Aleutian Islands and parts of southwestern Alaska through Friday. High Wind Warnings have been issued for the entire Aleutian Island chain. Across the Great Basin and northern Rockies, strong winds and dry conditions will lead to critical fire weather conditions Friday as a strong Pacific system moves inland. Read More >

Seattle, WA

Center Weather Service Unit

ZSE SIGMETs

Weather.gov > Seattle, WA > ZSE SIGMETs

 

 

 


Text of all SIGMETs Around Contiguous Western US
None Found
Description of Convective and Non-Convective SIGMETs

SIGMETs are Inflight Weather Advisories for Significant Meteorological hazards. A SIGMET is "widespread" in that it covers an area of at least 3,000 square miles. Note that the particular hazard may be present in only a small portion of the area at any particular time. SIGMETS are issued for:
  • Severe Icing (not associated with thunderstorms -- otherwise, it is a Convective SIGMET)
  • Severe Turbulence (similarly, only if not associated with thunderstorms)
  • Duststorms and sandstorms lowering visibility to less than three miles
  • Volcanic Ash

Convective SIGMETs are issued for severe convective activity, which implies severe turbulence, severe icing, and low-level wind shear. Specifically:
  • Embedded thunderstorms
  • A line of thunderstorms
  • Thunderstorms with heavy precipitation affecting 40%+ of an area at least 3,000 square miles
  • Surface winds 50+ knots due to severe thunderstorm
  • Hail 3/4+ inches in diameter
  • Tornadoes


Map of SIGMETs (including International)

 

Follow us on Twitter  Follow us on Twitter
Follow us on Facebook  Follow us on Facebook
Follow us on YouTube  Follow us on YouTube
ZSE RSS Feed  ZSE RSS Feed