Rex Block is here for the holiday weekend and he brought the thunderstorms. A “rex block” weather pattern is when a high pressure develops to the north or “above” an area of low pressure. Known as a blocking pattern, this setup results in a stagnant weather pattern in and around where the rex block sets up. The current block is out in the eastern Pacific which is resulting in Montana being in a cool, wet weather pattern. The jet stream is diving down from Canada, keeping a monsoon high from forming over the southwest United States. This high pressure would normally create heat and dry weather in Montana. The rex block will continue through this weekend. Independence Day will start out mostly sunny and pleasant but isolated thunderstorms will develop for the afternoon and evening. By the time fireworks displays kick off around 10pm, most of the thunderstorms will start fizzling out. There still is a chance for an isolated storm that could interfere with a fireworks display. Highs will be in the 70s. Friday will be partly cloudy with a few thunderstorms popping in the afternoon and evening, pretty much across the state. Highs again will be below average in the 70s. Warmer temperatures are likely Saturday and Sunday, as highs climb through the 70s and into the low 80s. However, scattered strong to potentially severe thunderstorms will develop in the afternoon and spread through the state into the evening hours. If you plan on being outside, be prepared for thunderstorms capable of producing powerful wind, large hail, heavy downpours and lots of lightning. Although there will be storms this weekend, there will be extended periods of sunshine and great weather as well. It’s not all gloom and doom! Scattered afternoon thunderstorms will stick around in the state through next week. The chance for thunderstorms could continue into the end of July, which would be great for diminishing fire danger.
Have a great day!
Curtis Grevenitz
