< p >我将提出一个解释。从经验中我想说它与美国气象系统(空气质量系统)活跃1980年5月18日,一周后(s)。< / p > < p >的背景:可以高压气团(酷,稳定)或低压(暖,更多的能量,更加不稳定,不稳定)。下一个图显示在红色低不稳定和温暖的系统,和蓝色的冷静,稳定的系统。(< a href = " http://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/highs-and-lows/pressure " rel = " nofollow noreferrer " >完整网站< / >)< / p > < p > < img src = " https://i.stack.imgur.com/FrlMU.jpg " alt = "空中系统" / > < / p > < p >进一步,我们考虑到俄克拉何马州的自然气象——作为一个地区一个不稳定的行业,在墨西哥湾的温暖潮湿的空气质量与冷相撞,干燥质量从西部和北部地区的一部分,大致知道是什么< a href = " http://en.wikipedia.org/wiki/Tornado_Alley " rel = " nofollow noreferrer " >龙卷风巷< / >。wiki页面上我们看到一个典型的系统条件有利于不稳定的天气。绿色质量是温暖的,蓝色是冷的和红色的行动是可能发生的。< / p > < p > < img src = " https://i.stack.imgur.com/GJdy2.png " alt = "龙卷风巷" / > < / p > < p >龙卷风频繁或其他恶劣天气事件的结果之间的冲突广泛不同的空气质量、温度、湿度和压力往往导致风暴细胞或其他不愉快的风/暴风雨的情况。< / p > < p >现在让我们回到我们的火山。我发现那些< a href = " https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps " rel = " nofollow noreferrer " >每天从NOAA气象地图< / >。当进入正确的日期,假设1980年5月18日和周之后,我们看到了各种系统。为简单起见,我选择5月18日,21日。 
The 18th of May there was a low pressure system about right over the volcano - which was ideal to transport and displace a lot of ashes very far. The 20th, at 7:00 am, there was a Low in formation over Oklahoma which would become full fledged the 21st (see figure) and there was bad weather that day over Oklahoma City because of clashing cell. Eventually causing precipitation (rain and ash?).
I am not a climate-meteo-specialist, but I have good confidence that this scenario could explain a part of the reason why there is ash in Oklahoma.