Scattered Severe Thunderstorms Across the Northern Plains; Fire Weather Concerns in the Western U.S.

Scattered severe thunderstorms are forecast across central and eastern North Dakota, as well as far northwest Minnesota Saturday (Slight Risk level 2 of 5). Damaging wind gusts are the primary threat. Elevated to critical fire weather conditions will persist through the weekend across the Western U.S. Isolated dry thunderstorms could lead to new fire starts over portions of the northern Rockies. 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)

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Scattered Severe Thunderstorms Across the Northern Plains; Fire Weather Concerns in the Western U.S.

ZSE SIGMETs