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Another Pacific Northwest Heatwave This Week

Thursday Morning Heatwave Update —

As the Portland / Vancouver metro area prepares to reach near record setting triple digits over the next two days, there is another record that could be in jeopardy. Unlike Portland’s nearly record cold and wet of June (-2.4 degrees below average and 4+ inches of rain), August is on track to be the hottest on record at the Portland International Airport (1940-Present) if the current trend continues for the remainder of the month. With the heatwave that is upon us, these numbers are certain to increase over the next few days. However, the average at the end of the month is what matters for the record books. The current pattern of warm and dry weather appears to be on track to continue for the foreseeable future.

Here is a look at the hottest Augusts on record at the Portland International Airport through yesterday (August 15th) —

YEAR / AUGUST AVE TEMP

2012 73.5 (as of 8/15)

1967 72.9
1986 72.3
1981 72.1
1972 71.7
1977 71.7
1971 71.6
1997 71.5
2004 71.5
1998 71.0

The last time PDX had two separate heatwaves (separated by at least 7 days or more), of 100 degrees or higher, in the the month of August, was 1990! Then 1987 before that. Then 1967 before that. That’s it! Nothing else all the way back to 1938 at the airport. So, if we hit 100 or higher today or tomorrow this will only the 4th such occurrence in 70+ years. It also marks only the 75th time in Portland Airport history to reach 100 or greater. Here are all of them, sorted by date —

Date / High Temp

8/4/2012 102
7/29/2009 106
7/28/2009 106
7/27/2009 103
8/15/2008 100
8/14/2008 102
6/28/2008 100
7/10/2007 102
7/23/2006 101
7/21/2006 104
6/26/2006 102
6/25/2006 101
7/24/2004 100
7/23/2004 103
7/29/2003 100
8/13/2002 102
7/28/1998 101
7/13/1996 100
7/21/1994 101
7/20/1994 103
7/19/1994 102
8/11/1992 101
7/30/1992 101
7/17/1992 100
6/22/1992 100
7/23/1991 100
8/11/1990 101
8/4/1990 100
9/2/1988 105
8/23/1988 101
7/25/1988 100
8/31/1987 102
8/8/1987 101
8/26/1986 100
7/19/1985 101
7/24/1984 100
5/28/1983 100
6/18/1982 100
8/10/1981 107
8/9/1981 105
8/8/1981 107
8/7/1981 103
7/21/1980 101
7/17/1979 102
7/16/1979 104
8/8/1978 101
8/7/1978 101
8/17/1977 105
8/16/1977 102
8/12/1977 104
8/11/1977 102
8/10/1977 100
8/7/1972 104
8/6/1972 102
8/11/1971 100
8/10/1971 101
8/9/1971 100
7/15/1970 102
8/28/1967 102
8/9/1967 102
7/31/1965 102
7/30/1965 107
7/12/1961 102
7/11/1961 104
8/8/1960 100
7/27/1958 102
7/19/1956 102
7/20/1946 102
8/5/1945 100
7/18/1944 104
7/2/1942 102
7/1/1942 105
6/30/1942 100
7/21/1938 101
7/20/1938 100

Dry Stretch Continues

The last measurable rainfall (more than a trace) at the Portland International Airport was on July 20th, which is nearly a month ago. If you look even further back, Portland has picked up less than a quarter of an inch of rain since July 1st. That is below normal. With the end of La Nina and the potential for the emergence of El Nino this fall, we may end up staying warm and dry for some time to come. At this point, no record dry streaks are being threatened in Portland.

Wednesday Morning Heatwave Update —

“It’s all systems go for a classic Pacific Northwest heatwave beginning today and lasting through Saturday. Computer model guidance continues to show a strong ridge of high pressure is forecast to build over the Pacific Northwest. Temperatures today (Wednesday) will top out in the 90’s across western Oregon and SW Washington. Today will be day number two of what could be as many as four to five days at or above 90 degrees at most locations from Medford, Oregon north to Longview, Washington along the I-5 corridor.”

“On Thursday, a thermal trough (heat low) will build north along the coast. This, combined with low level offshore (easterly) flow at the surface will boost temperatures even higher. Both Thursday and Friday have the potential for hitting triple digits in the Willamette Valley. Just how hot will it get? This will have a lot to do with exactly how much offshore flow develops. Looking back at Saturday, August 4th, models underplayed the amount of heating that resulted from the offshore flow. Models indicated high temperatures that day would top out about 97-98 degrees in Portland. Actual high temperatures ended up between 102-103 degrees. At the present time, forecast models are indicating highs of about 100 degrees on both Thursday and Friday. Either way you slice it, it will be very hot for the next few days and likely the longest stretch of heat in more than three years. Temperatures will cool over the weekend into the 80’s.”

Here is a look back at the heatwave of July 2009 at the Portland airport —

July 2009
25th = 90
26th = 93
27th = 103
28th = 106
29th = 106
30th = 96
31st = 94

Aug 2009
1st = 95
2nd = 94
3rd = 91

Monday Original Post —

Mother nature is planning to open up the oven door on the Pacific Northwest for the second time in the past two weeks. Confidence is growing in another three day heatwave where temperatures will rise above 90 degrees and peak around 100 degrees across western Oregon and SW Washington this week. Locations from Medford, Oregon north to Longview, Washington will be under the gun for hot weather. A large area of high pressure over in the inner mountain west will shift westward over the Pacific Northwest beginning Wednesday and last into the weekend. The peak of the heat will likely arrive Thursday and Friday with temperatures very close to 100 degrees. Most residents west of the cascades consider three days or more above 90 degrees as a “heatwave.” After two years without a single temperature above 100 degrees, the Portland International Airport reached 102 degrees on Saturday, August 4th, which set a new record for the date, besting the former record high for the day of 100 set back in 1990. To date, August is running 2.5 degrees above normal at the Portland airport with no measurable precipitation recorded so far this month. This was the first time the Portland airport had reached 100 since July 29th 2009. On average, August 20th is the approximate date where 100 degree record daily high temperatures begin to fall off the record books at the airport. The Portland International Airport has been as high as 105 degrees on September 2nd 1988. This is the only 100+ high temperature on record after September 1st at the Portland airport (1940-current) and is the highest temperature on record for this late in the year.”

Here is a look at the record daily high temperatures at the Portland International Airport (1940-Current) for the coming few weeks —

Stay tuned!
Steve Pierce, President
Oregon Chapter of the American Meteorological Society (AMS)
http://www.ametsoc.org/chapters/oregon

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Steve Pierce

Steve Pierce

Steve Pierce is widely known as Oregon and Washington's "go-to-guy" when it comes to fast, accurate historical meteorological research and forecasts. Steve is currently the President of the Oregon Chapter of the American Meteorological Society (AMS). Steve is also recognized as a regional weather commentator and blogger who can be heard on local radio stations and seen in print media outlets across the Pacific Northwest. His Weather Blog is hosted by the Columbian Newspaper in Vancouver. Check it out! He is a third generation resident of Vancouver, Washington and holds a degree in Communications. Both sets of Steve's grandparents migrated to Vancouver during World War II. One set traveled from Lenox, Iowa to work in the Kaiser Shipyards supporting the war effort. The other set came to Vancouver from Olympia, Washington to work as educators for the rapidly expanding Vancouver School District. When the war was over, both sets of grandparents decided to stay in Vancouver and continue raising their families, as did thousands of other families at the time. Those who are most familiar with Steve can attest to the fact that weather is his true passion. His love for "all things weather" began at the age of 7 when Mt. St. Helens erupted in 1980. He was fascinated with which direction the ash plumes were headed. Then came the very powerful windstorm of Friday, November 13, 1981, also referred to as the "Friday the 13th" storm. This was the strongest storm to hit the Portland / Vancouver area since the great Columbus Day Storm of 1962! At age 11, he was asked to publish an extended weather forecast for his elementary school's weekly newsletter. In the 1980's, at age 14, Steve was the youngest of KGW-TV's local "weather watchers" and would phone in his daily Vancouver weather stats to then television meteorologist Jim Little for use on-air. Steve has lived through all of the major Pacific Northwest weather events of the past 30 years, and then some. The most notable events include; the bitterly cold winter of 1978-1979, the record setting snow storms of January 1980, the summer heat wave of August 1981, the windstorms of November 1981 and December 1995, the severe arctic blast of February 1989, the record flood of February 1996, the historic ice storm of January 2004, the Vancouver tornado of January 2008 and the record setting snow storm of Christmas 2008. Not to mention every Mt. St. Helens volcanic eruption in between. With access to the most extensive set of historical weather records available to date, Steve has personally designed and integrated a proprietary system that gives him the ability to quickly locate and manipulate weather data as far back as the 1800's. As one local Meteorologist put it, "Steve has fast access to historical weather data that is needed for media, agriculture, business, personal, historical and other climatological needs. He can quickly manipulate the data in many different ways. His forecasts are also quite accurate, especially at longer lead times." Steve also provides local storm assessments, narratives and weather presentations to the general public, as requested. In his spare time, Steve enjoys spending time with his family, the outdoors, vacationing at his family's coastal cabin and just relaxing! By the way, do you like your weather on the "extreme" side? So does Steve! Whether it is collecting damage assessment data & photos after record setting 125 mph winds at the coast in December 2007, being one of the first on the scene after the January 2008 Vancouver tornado, or feeling (literally) the awesome power of 100 mph wind gusts at Oregon's Crown Point in January 2010, Steve has experienced it all! As Steve says, "don't just love weather, live weather!" Check out Steve's personal weather website at: http://www.piercevideo.com/weather.shtml