{"id":1179,"date":"2021-01-01T14:03:01","date_gmt":"2021-01-01T22:03:01","guid":{"rendered":"http:\/\/www.luterra.com\/blog\/?p=1179"},"modified":"2021-01-01T14:03:02","modified_gmt":"2021-01-01T22:03:02","slug":"2020-weather-summary","status":"publish","type":"post","link":"https:\/\/www.luterra.com\/blog\/?p=1179","title":{"rendered":"2020 Weather Summary"},"content":{"rendered":"\n
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This year will not be remembered primarily for its weather\nin most parts of the world.<\/p>\n\n\n\n

That said, 2020 did bring a record-breaking hurricane season\nand a continuation of worldwide weather extremes that are almost certainly\nlinked to climate change.<\/p>\n\n\n\n

Here in western Oregon, we mostly saw a continuation of the\nprotective bubble that has been over us for the past few years, with muted\nheadlines and no major floods, storms, heat waves, or cold snaps.  The one notable exception arrived late on\nSeptember 7 and continued for the next 48 hours.  Interrupting a month of late-summer sunshine\nwith warm days and gentle winds, a cold and dry airmass came barreling down\nfrom the Canadian tundra,  generating\nunprecedented northeasterly winds and single-digit humidities.  Had this happened in October \u2013 when such\nevents are more common \u2013 crews would have simply spent a few days cleaning up\nfallen trees and restoring power to outlying areas.  But ahead of the first fall rains and following\non weeks of dry heat, the winds proved catastrophic, fanning existing small\nfires to hundreds of thousands of acres overnight and igniting many new ones\nfrom sparking power lines.  Four\nunstoppable conflagrations raced down the valleys of the Clackamas, North\nSantiam, McKenzie, and North Umpqua rivers, obliterating small towns and\nplacing most of the eastern Willamette Valley on some level of evacuation\nnotice until the winds died down.  <\/p>\n\n\n\n

Farther west, away from the fire threat, the easterly winds\ncarried vast plumes of smoke over the Pacific, first dropping ash under ominous\norange skies and later leaving the valley in a cool gray stagnant smog, thick\nenough to block summer sunshine and create winter-like inversion conditions and\nongoing hazardous air quality.  At its\nthickest, the smoke knocked nearly 30 degrees off of daytime temperatures,\ngenerating a strange and short-lived dystopian November in between summer and\nfall.  Blessed rain arrived in quantity\non September 18, clearing the air, mostly extinguishing the fires, and putting\nan end to the 11-day pyrogenous climatic aberration.  Those in California would not be so lucky;\ntheir historic fire season began months earlier and their rains would not\narrive until much later.<\/p>\n\n\n\n

Temperature trends<\/em><\/p>\n\n\n\n

The year\u2019s highest temperature \u2013 exactly 100.0\u00baF at our place\n\u2013 arrived without much fanfare on August 15: a one day blip with a couple of\n90-degree days on either side.  With\nseventeen days above 90\u00ba, the summer was substantially warmer than mild 2019\nbut on par with other recent years.  The\ncoldest temperature of 22.4\u00ba was also reached without much notice on both\nNovember 9 and December 29, though the low of 22.7\u00ba on October 26 flirted with\nearliest-coldest records and brought a resounding close to a long growing\nseason.  The entire year remained within\nthis 77.6\u00ba range, somewhat remarkable considering that some individual summer\ndays covered nearly 2\/3 of that distance between morning and afternoon.  We had no real intrusions of arctic air; low\n20s are about the limit of normal dry winter days absent advection of colder airmasses\nfrom the northeast.  With no arctic air,\nwe also had no snow to speak of; only a few flurries from the coldest\nlate-winter showers.  We did have a total\nof 76 days with lows below freezing \u2013 the same number as 2019 but well above recent\naverages.  This reflects a recent trend \u2013\nperhaps exacerbated by climate change \u2013 of a greater proportion of clear fall\nand winter days with frosty mornings and comparatively fewer days of clouds and\nrain.  Overall, the year averaged 0.5\ndegrees above long-term averages \u2013 in keeping with the previous three years\nthat have been unremarkable in their temperature normalcy.<\/p>\n\n\n\n

Precipitation trends<\/em><\/p>\n\n\n\n

The Willamette Valley was in drought status for all of 2020,\nat times and in places listed as severe, after inheriting a significant\nshortfall from October-December 2019.  This\nwas an odd sort of hydrologic drought: more a result of long-term shortages\nthan short-term patterns and so with limited effects on farmers and\ngardeners.  Total rainfall for 2020, at 36.42\u201d,\ncame in at 90% of normal \u2013 higher than 2018 and 2019 but not yet enough to\nbreak the longer-term drought.  With\nperiods of dry clear weather seemingly becoming the wintertime norm, it is\nbecoming more important to win the atmospheric river lottery; to end up beneath\nthose stationary bands of intense rainfall dropping inches at a time and\nbringing us closer to our precipitation quota. \nMore often than not in 2020 those bands took aim at western Washington,\nbut deluges from November 13-18 and December 16-21 put dents in the hydrologic\ndeficit.  As I write this, the near- and\nlong-term winter forecasts look moist, with a La Ni\u00f1a pattern directing the\ndominant storm track toward the Pacific Northwest.  With luck this will be enough to end our\ndrought status moving into the 2021 growing season, with snowpack, streamflows,\nand aquifers recharged.<\/p>\n\n\n\n

Monthly notes<\/em><\/p>\n\n\n\n

January<\/strong>was an exceptionally wet and dreary\nmonth, even by Oregon standards. \nFlooding rains stayed to the north, and we never received more than 0.76\u201d\non any one day, but rain fell on 27 of the month\u2019s 31 days as we were locked in\nan onshore flow pattern with a continuous parade of Pacific fronts.  The monthly total of 8.93\u201d was the highest of\nthe year, but coming on the heels of a dry fall and followed by a dry February\nthrough April it was not enough to offset the year\u2019s overall droughtiness.  January averaged 5.2 degrees above normal \u2013\nthe year\u2019s largest departure thanks to the monthlong pattern of warm-ish clouds\nand rain.<\/p>\n\n\n\n

February<\/strong> saw a\nswitch to unseasonable sunshine, with rain on only 11 of 29 days totaling 1.96\u201d,\nor 39% of average.  The remaining days brought\nfrosty mornings and sunny afternoons, exceeding 60 degrees by the end of the\nmonth despite a below-normal monthly mean.<\/p>\n\n\n\n

March <\/strong>brought a\ncontinuation of the same mostly-dry, mostly-sunny pattern up until the equinox,\nwhen the pattern finally shifted to cool and wet.  That was too late to make up for a monthly\nrainfall deficit (3.07\u201d, or 69% of normal), and the continued frosty mornings\nled to a -2.4\u00ba temperature departure for the month despite a feeling of late\nwinter warmth.<\/p>\n\n\n\n

The brief cool-and-wet interlude ended April<\/strong> 5, ushering in an above-normal, mostly-sunny month of 60s and\neven low 70s for daily highs.  A low of\n27.1 on the 3rd<\/sup> gave orchardists heartburn \u2013 though in general\ntemperatures did not drop as low as feared and blossoms and young fruits were\nspared.  The 14th<\/sup> brought the\nseason\u2019s last frost at 31.1\u00ba, and drying conditions allowed farmers and\ngardeners to get crops in on schedule. \nThe beautiful spring weather was largely overshadowed by the early days\nof the COVID-19 pandemic and the associated statewide shutdown that even\nincluded closures of beaches and outdoor recreation.<\/p>\n\n\n\n

May<\/strong> brought\nabove-average precipitation, much-needed but not exactly welcomed by those\nwishing to till and plant.  Dry windows\nfrom the 7th<\/sup>-11th<\/sup> and 24th<\/sup>-29th<\/sup>\nbrought highs in the 80s and an early taste of summer, though some days in the\nmid-month wet spell struggled to reach 60 degrees, keeping bees in their hives\nand putting a damper on dreams of a bumper honey crop.<\/p>\n\n\n\n

June<\/strong> had rain on\nevery day from the 6th<\/sup> through the 16th<\/sup>, largely washing\nout blackberry blossom nectar at peak bloom and leading to an anomalous beekeeping\nyear in which the early-season bigleaf maple honey was a large proportion of\nthe harvest.  The rain only totaled 1.61\u201d,\nslightly above normal but enough to delay the onset of summer drought and\nprolong blooms and green lawns. <\/p>\n\n\n\n

After a sprinkle on the first day for 0.01\u201d July<\/strong> was completely rain-free with\nwarming temperatures.  The first third of\nthe month had highs in the 70s, then mostly 80s in mid-month with five days in\nthe 90s at month\u2019s end.<\/p>\n\n\n\n

August<\/strong> can be hot\nand sticky but not this year, with highs around 85\u00ba on most days and only a\nbrief and mild mid-month heat wave topping out at exactly 100\u00ba on the 15th<\/sup>.  One brief shower \u2013 0.04\u201d on the 6th<\/sup>\n\u2013 provided minimal disruption to drying grains and seed crops.<\/p>\n\n\n\n

September <\/strong>started\nout in the 90s with more of the same in the forecast, but the smoke beginning\non the 8th<\/sup> dimmed the sun sufficiently to lower daytime highs by\nover 20 degrees.  The respite from the\nheat made it easier to stay indoors out of the smoke, though clean air became a\nrelative term as ash seeped in around doors and windows.  Were it not for the fires the month would\nhave been historically warm; as it was September finished slightly above\naverage.  After an inch of fire-quenching\nrain on the 18th<\/sup>, additional rains after the equinox brought the\nmonthly total above average and paved the way for an early fall re-greening.<\/p>\n\n\n\n

Aside from rain on the 9th<\/sup>-14th<\/sup>, October<\/strong> was mostly dry, continuing the\npattern from the previous two years and a boon for late seed harvests delayed\nby the days of smoke.  Total rainfall at\n1.58\u201d was just 50% of normal.  After no frost\nthreats through September and mid-month, a killing frost on the 22nd<\/sup>\nwas followed by a low of 22.7\u00ba on the 26th<\/sup>, ensuring that even\ntarp-covered tomatoes and peppers grew no more. \nAs a gardener I must say I prefer to have a clear end to the season, as\nopposed to those years where we harvest increasingly flavorless peppers until\nThanksgiving.  <\/p>\n\n\n\n

We managed to \u2013 just barely \u2013 exceed normal rainfall in November<\/strong> \u2013 thanks to a mid-month\natmospheric river.  With dry soils and\nlow streamflows, this rain didn\u2019t cause the flooding concerns that a similar\nevent would create later in the season. \nOverall the month brought a wide variety of weather \u2013 warm sun at the\nbeginning, warm rain, cold frosty mornings, a rare sunny Thanksgiving, and\nfinally some cold inversion fog, and averaged a bit below normal\ntemperature-wise.<\/p>\n\n\n\n

Early December<\/strong>\noften brings the year\u2019s coldest temperatures in a dry spell; the dry spell\narrived on schedule in 2020 but not the cold, with highs reaching over 55\u00ba and\nlows only around 25\u00ba.  Mid-month through\nthe solstice brought another atmospheric river, followed by occasional rain\nthrough month\u2019s end but not enough to reach the 7.14\u201d average for the wettest\nmonth of the year.  After a foggy and\nrainy Christmas, bright sunshine on the 27th<\/sup> and 28th<\/sup>\nbrought hope for longer days ahead and brighter times in 2021.<\/p>\n","protected":false},"excerpt":{"rendered":"

This year will not be remembered primarily for its weather in most parts of the world. That said, 2020 did bring a record-breaking hurricane season and a continuation of worldwide weather extremes that are almost certainly linked to climate change. … 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\/1179"}],"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=1179"}],"version-history":[{"count":1,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1179\/revisions"}],"predecessor-version":[{"id":1182,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/1179\/revisions\/1182"}],"wp:attachment":[{"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1179"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1179"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.luterra.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1179"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}