{"id":629,"date":"2013-09-05T20:19:23","date_gmt":"2013-09-06T03:19:23","guid":{"rendered":"http:\/\/www.luterra.com\/blog\/?p=629"},"modified":"2013-09-05T21:41:09","modified_gmt":"2013-09-06T04:41:09","slug":"and-then-it-rained","status":"publish","type":"post","link":"https:\/\/www.luterra.com\/blog\/?p=629","title":{"rendered":"And then it rained"},"content":{"rendered":"

Update:\u00a0 <\/strong>Albany rain total now up to 3.73″.\u00a0 That may well be an all-time summer season record for them.\u00a0 Still only 1.60″ here.
\n<\/strong><\/p>\n

Summer weather here can be pretty boring.\u00a0 Either the wind blows off the land, in which case we have hot days, cool nights, lots of sun, and no rain; or the wind blows off the sea, in which case we have cooler days, milder nights, partly cloudy skies, and still no rain.\u00a0 That is all a function of the ocean being cooler than the land and the air above it.\u00a0 (In the winter, when the ocean is warmer than the land and the air, we see lots of evaporation and convection, with rain becoming the dominant pattern.)<\/p>\n

There are two ways we can get rain in the summer, and they are about equally common.\u00a0 First, we can get an unseasonably cool air mass dropping down over the ocean from the north, which essentially revives the winter pattern in a half-assed way.\u00a0 This brings cool, gentle rains with little to no thunder, and we last saw this happen in the summer in July of 2011.<\/p>\n

Second, we can have a low pressure system set up to our southwest over the ocean, which is pretty much the only way we get summer thunderstorms.\u00a0 In the Midwest, there is a fairly frequent northward flow of moist air from the Gulf of Mexico.\u00a0 In the Southwest, a similar pattern happens in the summer creating the monsoon season.\u00a0 Here, because we are so close to the cold, non-storm-inspiring ocean, we need a very specific pattern to bring moist air up from the south or southeast.\u00a0 With a low offshore to the southwest, moister air from over the ocean off California is pulled onshore and northward over the southern Oregon mountains.\u00a0 There it is heated by the warm land, triggering convection and thunderstorms.\u00a0 If the flow is just right, these storms then continue to move northwestward over the Willamette Valley.\u00a0 The pattern itself occurs several times each summer, but usually the moisture is too limited and the storms peter out soon after drifting away from the mountains.<\/p>\n

This time the flow over California tapped the remains of a tropical system, bringing moisture in the atmosphere to 2-3 standard deviations above normal.\u00a0 A east-west band of storms developed, moving northward into our area and being stretched westward out over the ocean by the circular flow.\u00a0 It arrived with a bang just after 2 pm, bringing more lightning than I’ve seen since a similar event on June 4, 2009.\u00a0 That storm, which also came from the southeast, was stronger but passed over quickly, dropping a quick inch of rain.\u00a0 In this storm, the lightning kept up for two hours, striking five times within a mile of the library where I was working and once just down the block (or possibly hitting the building itself).\u00a0 The center of the low-pressure circulation moved overhead shortly after the rain arrived, essentially trapping the band in place.\u00a0 Instead of moving, it began to rotate around us, keeping us under moderate to heavy rain for 4.5 hours.\u00a0 It has finally stopped now, leaving us with 1.59″ for the day.\u00a0 That is admittedly not high by Minnesota standards, but it is above our monthly average of 1.43″, more than double the daily record of 0.70″, and the third-highest one-day total in September since 1889.\u00a0 Albany got hit by a stronger cell in addition to the stalled band, bringing totals there to around 2.5″ which is probably an all-time September record.<\/p>\n

With the soil parched from three months of little to no rain, there was almost no runoff.\u00a0 Just two hours of thunder to warm a Minnesotan’s heart and almost two inches of rain to moisten the earth and spark off fall mushroom season.<\/p>\n","protected":false},"excerpt":{"rendered":"

Update:\u00a0 Albany rain total now up to 3.73″.\u00a0 That may well be an all-time summer season record for them.\u00a0 Still only 1.60″ here. Summer weather here can be pretty boring.\u00a0 Either the wind blows off the land, in which case … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/629"}],"collection":[{"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=629"}],"version-history":[{"count":3,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/629\/revisions"}],"predecessor-version":[{"id":631,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/629\/revisions\/631"}],"wp:attachment":[{"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=629"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=629"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=629"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}