National Weather Service United States Department of Commerce

Regional Outbreaks of Severe Weather Through Early Next Week; Early Season Heat Wave across the South

Active spring pattern across the center of our nation with several episodes of severe weather and heavy rainfall expected into next week. The potential for very large hail, long track tornadoes, severe wind gusts, frequent cloud to ground lightning strikes and flash flooding are in the outlook. Furthermore, dangerous early season heat wave continues for the Gulf Coast states into early next week. Read More >

 

 

 


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)