Severe Thunderstorms Possible across the North Sunday

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 Storm Prediction Center Day 2 Outlook for May 26th
The Storm Prediction Center (SPC) Day 2 Thunderstorm Outlook for Sunday, May 26th.  The yellow shaded area represents where SPC believes there is a slight risk of severe thunderstorms Sunday.  The green represents where SPC believes where thunderstorms will generally occur Sunday.

A potent upper low across the Pacific Northwest Saturday afternoon will impact the Cowboy State through much of the upcoming week.  This system will send daily disturbances across the area with a nearly stationary front oscillating between central Wyoming and extreme eastern Wyoming. This front will separate a moist and unstable air mass to the east and north, and a relatively dry and stable air mass west and south. In the moist and unstable atmosphere isolated to scattered thunderstorms are expected, and some of these storms could become severe with large hail and strong damaging winds.  Also enough wind shear will be in place at times that isolated tornadoes cannot be ruled out.   The area of greatest concern for severe thunderstorm development Sunday will be across the Big Horn Basin and Johnson County.  Thunderstorms are also expected across western Wyoming Sunday afternoon and evening, but are expected to weaker.  Dry and warm conditions are
expected across much of Wind River Basin, Natrona County and southwest Wyoming. On Memorial Day much of the area will have a chance for thunderstorms with the strongest activity across the north and east.  Thunderstorms remain in the forecast through at least Thursday of next week...and the potential for strong to severe thunderstorms will persist at times.

 Weather map for Sunday afternoon  Closer view on where severe weather might occur Sunday
The weather map for Sunday afternoon.
A strong upper low will be over the Pacific Northwest.  A warm and dry atmosphere is expected across southern Wyoming ahead of a weak cold front over western Wyoming, and a nearly stationary front across northern Wyoming.  North of the stationary front and east of the weak Pacific cold front, a moist and unstable atmosphere and good wind shear will result in the potential for severe thunderstorms.
A closer view on where severe thunderstorms could occur Sunday afternoon and evening.  The Big Horn Basin and Johnson County will have the best chance of seeing severe thunderstorms with large hail and damaging winds possible.  An isolated tornado cannot be ruled out.   


Do you know what the term "slight risk" means? As this graphic explains, it's all about the coverage of storms and number of expected severe weather reports. Is that what you thought you meant?

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