The Last 80 Degree Day?

What a day!  But was this it?  The last taste of Summer?  There’s a good chance it was if you look back at history.  The average last 80 degree day of the season here in Portland is September 27th.  We’ve gone through 5 Octobers (since 2004) without seeing that 80 degree mark.  In fact last year we only had two days above 70, the year before only 3!  71 degrees was the best we could do in October 2009.

This points out how quickly our weather cools (and turns wet) during the month of October.  It’s the fastest changing month in our area.  Average high temps cool from around 70 on the 1st to upper 50s by Halloween.  No other month sees the temperature change so quickly.   The quickly decreasing sun angle, long nights, and cooling continent finally catch up and overcome the warm late summer atmosphere.

I dropped a bunch of the 7 Day forecast numbers because I felt they were just too warm for this time of year and the weather pattern.  For example, it’s obvious that we’ll be socked in a westerly flow and saturated atmosphere below 5000′ on Sunday.  On October 3rd that’s well down into the 60s…maybe ONLY 60.  Tomorrow too, I think 79 is way too warm.  It took great effort (offshore flow) to get us into the mid 80s today.  Flow goes onshore tomorrow, so a 10 degree drop seems reasonable.

Chief Meteorologist Mark Nelsen

142 Responses to The Last 80 Degree Day?

  1. 00Z GFS – Very heavy rain in la la land showing up. Over 4″ of rain from the 17th to the 20th and highs around 50. Looks like some weather action is only a couple of weeks away

  2. W7ENK says:

    If this boring nothingness weather keeps up, at this rate my pointless daily weather numbers will be the only thing posted on here… for days! :yawn:

    Only 8 days until the 48th anniversary of one of the PNW’s most epic wind events of modern times… FWIW. 😀

    [Milwaukie] 10/4/2010
    61.9°F High
    48.0°F Low
    WNW 9.6 mph at 2:45p
    Trace

  3. Karl Bonner says:

    Today we had a really strong west wind in The Dalles. Didn’t check stats but I bet it was roughly 20-30 mph, more during gusts. And it happened after the weekend storm had largely departed toward the east.

    I’d think that by early October, any strong west winds would disappear very quickly when the system shifts off to the east. Even in a stormy pattern, the amount of wind we had today ought not to get the wind speeds this fast.

    I wonder what caused it?

  4. W7ENK says:

    *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets* *crickets*

    • Boydo3 500' North Albany says:

      Isn’t interesting how in the spring we have the ribbet, ribbet, ribbet, and in the fall we have the cricket, cricket, cricket!!!

  5. Rob "Wrath" S.E. Portland says:

    Watch Storms Live!!!

    St. George, Utah
    http://skywireusa.com/hotspot/VernonWorthenPark.php
    Several thunderstorms migrating northeastward out of Nevada and Arizona are now moving into southwest Utah. Seeing plenty of flashes. In case anyone is mildly interested or feels t-storm deprived.

  6. Oct 4 2010 Oregon Temperature Extremes

    Warmest:
    High 74 at Beulah
    Low 59 at Nyssa & Blalock

    Coolest:
    High 42 at Pine Mtn
    Low 32 at Timberline Lodge

    Largest Diurnal Change: 27 degrees
    Dallas (66/39)

    Heaviest Rainfall: 1.31″ at Moon Hill (Steens Mtns)

  7. Boydo3 500' North Albany says:


    Maybe this?

  8. Boydo3 500' North Albany says:

    Shot this pic the other day in my front yard.

    [IMG]http://i53.tinypic.com/2rfe91k.jpg[/IMG]

  9. WEATHERDAN says:

    Henry Margusty at Accu-Weather has just came out with his winter forecast. He has us down as very cold and 200% snowfall. In Salem’s case that would give us about 15 inches of snow. Take it for what it’s worth, but there is another forecast for a cold and snowy Winter. There are none for a mild Winter. It felt like Autumn out there today.

    • Garron near washington square says:

      No kidding WEATHERDAN. I have yet to see (1) forecast for a mild winter ahead. Amazing! We will see, I hope that 200% ends up being 2000% snow fall of normal.

    • PaulB/Eugene says:

      I think 3-6F below normal temps over the Dec-Feb period possible, with Jan/Feb representing most of the cold anomalies. March likely on cold side as well.

      When talking about snowfall…200% overall may not be a bad guess, but that is with GREAT uncertainty. Some may get normal amounts of snow, which is not very much, or others may get 400%…hard to say.

      We have a long way to go. Never have I seen so many long range forecasts for PacNW being cold to the point that they are getting old.

    • Andrew Johnson says:

      There is such a buildup for a cold winter that people will be screaming bust by mid november if we haven’t had a cold snap yet lol.

    • Ryan (Walnut Grove) says:

      3-6 degrees down on average would be a pretty epic departure all told. My guess is about 1-2 degrees below average for November/December. Maybe 2-3 for the Jan-Feb time frame.

      Overall 75% to 110% average snowfall in the valley. I would tend to agree with 150%+ average snowfall in the foothills and mountains.

      La Nina typically doesn’t bode well for the valley and snow fall… It does increase the likelyhood of 250′ or higher snow events that drive all us weather nerds nuts.

    • Chuck on MT Scott says:

      I’ll take 250′ 🙂 should be fun up here this year.

  10. Andrew Johnson says:

    The 12z shows some crisp weather out in la la land. Still pretty dry.

    • Ryan (Walnut Grove) says:

      It looks fairly typical for October… Slow ramp up to wetter and cooler weather.

      I like the current models.

  11. Here are a few low temps from the Portland CWA list this morning:

    32 Timberline Lodge
    35 Timber Junction
    39 Brush Prairie, Yacolt & Hillsboro. (and many more)

  12. Low of 42.6 here at BG lake with fog this morning. This was the coldest morning since August 20th when I hit 42.4.

    • Garron near washington square says:

      This was surely a change from the humidity of last week. Even a few 30’s popping up at Mc Minnville, and HIO. Now back to a balmy 49 D/F.

  13. Coldest am here in quite a while….44.5°

  14. Tyler in Hazel Dell says:

    Surprisingly clear and cool morning. There are clouds streaming in from the SW, but so far, the sun is shining and temps are in the mid 40s, one of our cooler mornings so far.

  15. RopWaltemate says:

    Got down to 43.7 and looking SW looks like we might get some rain today.

    • Garron near washington square says:

      Thanks Mike,

      I lived in the middle east for 5 years and can attest to those evil winds that heat the air like a blast furnace. We lived 2 blocks from the Arabian gulf. In the mornings, before the wind got going, your sunglasses would steam up, and you’d literally have to peel your clothes off from the humidity. Then the wind would go off shore in the afternoon, and sand blast you with 120+ degree heat. As the evening wore on, the onshore effect would replace the dry air again with 80% humidity from the gulf and the temps not dropping much below 100 D/F at night.

  16. eugene in vancouver says:

    I figure I lost about 80 percent of my tomatoes this year due to the weather and the slugs. Yuck! Let’s hope for some excitement this winter to make up for it my lack of BLTs

    • RobWaltemate says:

      My fathers corn is only about 2 feet tall and the ears are small. Most of the garden didn’t do anything, but the beans are ok. Just not warm enough! Not much sun at all down here 3 miles north of Long Beach WA. OH, but the weeds seem to be doing real good! LOL

  17. Kyle says:

    I have a microclimate question that’s bothered me:

    Does Lake Quinault get the high winds Aberdeen WA gets since Lake Quinault has 2000+feet mountains to the south and east?

  18. Karl Bonner says:

    I have another nerdy question, one concerning the microclimates on south-facing hillsides. If Mark makes another blog entry before anyone has a chance to answer, I may repost in the next entry’s comment section so that people get a chance to see it.

    It has to do with the East Gorge. There’s a place called Catherine Creek on the north side of the river, a nature trail about 5 or 6 miles east of Bingen / White Salmon and directly across from the Memaloose rest stop. (Rest stop is about 4 miles east of Mosier) You have to go off of highway 14 and up a side road to get to it. It has a moderate slope to the hillside though there are no really steep hills anywhere behind it. There are, however, plenty of high spots due west of the park since the river bends to the north at Mosier.

    I’m wondering if the combination of steep hills/mountains to the west and gradual hills to the north would have any kind of appreciable effect on air temperatures there during a sunny day in spring or, especially, fall. I recall many crisp and contrasty October days in the Gorge where shaded spots have much lower afternoon air temperature than spots in the sun. If shade keeps the heat out, will a south-facing incline affect temperatures to a similar degree? (key word is similar degree!)

    Another question is whether places in The Dalles that are out of the immediate path of the Gorge (the curve in the river means the town itself is a good 2-4 miles south of the airport, which is directly in the path of the west wind. Would this translate into any significant temperature disparity in the AVERAGE summer temps, meaning that The Dalles has more growing heat units than Dallesport?

    • Mountain Man says:

      I live in the gorge and I am not familiar with the micro climates over by The Dalles. I can say that the basic rules of micro climates work for anywhere in the Gorge. There is the obvious which is elevation. Then there is sun exposure and wind exposure. There are major contrasting micro climates in my neighborhood. I did live on the south slope of Mt. Pleasant for quite a few years at 850 ft. I have property on the north slope of Mt Zion (next hill to the east opposite side from Cape Horn.) I currently live at 1,150 ft. on the west side of Archer Mountain (20 mi. E of Washougal). The low end of my property on Mt Zion is only 650 ft. My property is almost always 6-9 degrees colder/cooler then my old house. On a hot summer day when we would hit 95 at my old house on the south slope, it is only about 86-88 at my property on a north slope even though the two locations are only 2 miles apart. Obviously the angle of the sun on a north vs. south slope makes a difference. I would imagine as a general rule that the Oregon side of the gorge facing the river is also somewhat cooler then the Washington side of the gorge facing the river due to sun exposure.
      The other factor is wind. Obviously both sides of the gorge are exposed to wind which helps suppress extremes. My property which is protected from the wind pools cold are in winter. I can’t count on all my fingers and toes how many times it was 38 degrees and either windy or raining at home or even up at 1,200 ft on Mt. Zion, yet on the wind protected side at my property (Canyon Creek) it was calm and frozen or snowing. In-fact I think I even get less snow at home now at 1,150 ft. then my property on that north slope at 650 ft. I think the answer to your question is yes. There can be a combination of factors but in general if conditions are relatively calm there can be a significant difference between a north facing slope and a south facing slope.

  19. PaulB/Eugene says:

    Sun PM model review…not much to speak of for the coming week. Minimal precip in the next 24 h…then looks dry with temps not straying too far from norms during the next week…another wet system heads into BC/Vanc Is around day 7/8, clips WA with some rain…bet it stays mostly dry here…then dry again early next week. ECMWF, Canadian, JMA, Canadian, Ensembles suggest this (GFS this evening suggested a bit of precip day 7/8 in OR, although that is an outlier).

    Things will inevitably change…Nov will be wetter…Oct on dry side through mid month. Low blogginess to continue.

    • Mike (Orchards 255') says:

      Main stormtrack continues to be to the north of us. Been consistant the past few weeks now.

      Still a pretty active “Gulf”.

      54°

    • RobWaltemate says:

      Oct seems to me that it is always somewhat dry, and we don’t really start to see rain until the 31. Then here at the coast when someone say Nov. I think 38 and rain (because I work outside). Good time to go to Hawaii if ya can, but got to be back before the 2nd half for the storms!

  20. W7ENK says:

    [Milwaukie] 10/3/2010
    67.1°F High
    55.6°F Low
    WNW 5.8 mph at 9:51p
    Trace

  21. Kyle says:

    Karl see reply.

  22. …ahhh you yunguns …why i can remember back in ‘ought 7 during dull spells when this blog used to be as quiet as fog on a dark night……

  23. High 59
    Low 54

    Cloudy, cool day. So far a dry day as well.

  24. Karl Bonner says:

    I wish that during the periods where Mark doesn’t post for several days, that more of us would make an effort to keep the conversation on the nerdy side – topics like the sun angle, inversions, averages vs records, and anything more than simple temperature/wind home weather reports and hoping for exciting storm activity.

    I’m not trying to whine or expect others to agree with me on this or in general sound negative. However if nobody else is going to step up to the plate on this one, I will do so myself. I ask for nothing more than modest respect on this one.

    • pappoose in scappoose says:

      I respect what you like Karl, but I like to hear home weather reports. Also like to put in my hope for a GRANDIOSE LOW and maybe a Siberian Express or perhaps a Pineapple Express. (or any other exciting storm activity) Hahaah!

    • Runrain says:

      Well, the river is really low. Thats kind of interesting. Lots of people burning yard debris. And the farmers markets are real light on supply as a result of the cool weather. Any predictions for Halloween weather this year?

    • Karl Bonner says:

      I don’t dislike weather reports, on the contrary I love reading them. It’s when there’s NO nerdy commentary that I get anxiety.

    • pappoose in scappoose says:

      Sorry Karl, had some trouble analyzing your comment.

    • Karl Bonner says:

      I’m hoping that this is the year we get 65+ sunshine on Halloween, and it stays balmy well into the night. Oddly enough a warm and dry Halloween seems more spooky to me than a wet or cold one, though I really loved 2003 when it was in the upper 20s for the drunken party and the local punk rock bands around midnight in Eugene.

    • Kyle says:

      I have to agree with you as this blog won’t get into name calling/almost non stop insults on page 2 or 3 when it comes to ‘nerdy’ comments.

  25. W7ENK says:

    All quiet on the Fox 12 Weather Blog…

    We really need some definite prospects for some exciting weather, and soon. The chirping of the crickets in here is almost overwhelming!

  26. Timmy_Supercell (Hillsboro) says:

    Now we are coming more towards Fall weather, light sprinkles/mist out this AM with occasional light breezes… Still feels comfortable though

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