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It's the Wind Not the Heat

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There has been a lot of talk about the warmth of this weekend, but the REAL story is about the winds, not the temperatures.  Unusually strong easterly winds. Today was a warm, but pleasant day for many, with Seattle getting up to the mid-80s away from the water, while highs hit around 90 from Olympia down into the Willamette Valley. But the warmth was mitigated by a wonderful breeze in many locations, with the high winds today reaching around 20 mph over western Washington/Oregon and 30-35 mph east of the Cascades.   The weather situation today and tomorrow are very different from the major heatwave events and that explains the winds. Considering the upper level (500 hPa) pattern, one notes an elongated ridge of high pressure/heights to our north, which is NOT the canonical location/shape to give the Northwest a major heatwave.  A further non-standard feature is a low center to our south.   All of this is VERY different than the situation in June 2021. This pattern is producing an inte
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Heatwaves, Duststorms, and More

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 We have some interesting weather ahead. The key features will be the development of a strong upper-level ridge over British Columbia and a low sliding westward across southern Oregon (see upper-level map for 8 PM Sunday). Predicted 500 hPa Height at 8 PM Sunday There are some suggestions in the media and a few blogs that this situation is like June 2021.  This is not correct.  The shape, size, intensity and location of the high are different (and much less intense) and the low center was absent in 2021.  Subtle differences are everything. So let's go through the next few days in detail. Today (Thursday) has been near perfect, with low 70s around the region at 3 PM. The predicted temperatures at 5 PM Friday are shown below.  Cooler along the coast and Northwest Washington.  Just reaching 80F in Seattle, but warmer (low to mid-80s) over southwest Washington and the Willamette Valley.  Also low 80s in the lower Columbia Basin. 5 PM Friday On Saturday at 5 PM, high temperatures will
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The Upcoming Spring Heatwave

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During most Mays in the Northwest, there is a several-day period of warm weather, driven by the strengthening sun and a favorable atmospheric circulation (high pressure and offshore-directed winds). During such periods, the western lowlands can surge well into the 80s, while the Columbia Basin warms well into the 90s. Such a period is ahead starting this weekend. Just to give you some perspective, below is a plot of the warmest temperature each year in Seattle for the period 5-25 May.  Most but not all years have a least one May day above 80F, with a number of years seeing temperatures surge about 85F.    Interestingly, there is no upward trend in warm days over the period of record. The latest forecast from the NOAA/NWS National Blend of Models, which combines the forecasts of many modeling systems statistically, predicts the mid-80s over the weekend in Seattle, surging to 90F on Monday. The Tri-Cities will be firmly in the 90s starting on Friday and will stay there for days (see the
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How Does the Strengthening El Nino Influence Summer Weather in the Northwest?

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NOTE:  Last Day to Register for the NW Weather Workshop (see bottom of blog for information. ______________________________ I have gotten a number of emails wondering about the impacts of the developing El Nino on our summer weather.   And several media outlets have already suggested that El Nino will cause enhanced heatwaves around the world...so folks are a bit worried (some samples below)   The Bottom Line:    The correlation of El Nino (warmer than normal water in the central and eastern tropical Pacific) on Northwest summers is quite weak.   The El Nino signal tends to increase after January 1. NOAA provides a number of graphics and studies that have taken on this question. For example,  below is the correlation between summer (July-August temperatures) and the temperature in the central/eastern tropical Pacific (the Nino3.4 area).   A positive value would be consistent with El Nino causing the summer temperatures to warm. Interestingly enough, El Nino results in COOLING over mos
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The Northwest Has Been Having a Thunderfest! Why We Can Blame this on California Low Pressure.

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Thousands of lightning strikes have hit the Pacific Northwest during the past several days.   A stormfest of lightning! Lightning over the Kitsap Peninsula Picture courtesy of Adam Sapek For the 24-h ending at 1 AM this morning (Friday), lightning was widespread over the entire region (each + or - sign is an individual lightning stroke) During the previous day, eastern Oregon and Washington enjoyed the lightning shows Wednesday had a strong band crossing northern Idaho and more over southwest Oregon While Tuesday had lightning filling southwest Washington and western Oregon. So why has the Northwest enjoyed this flashy period?   Every Northwest resident instinctually knows the answer: Blame California! And they would be right. During the past several days, a low center has been parked along the California coast (see the 500hPa chart--for about 18,000 ft--from Tuesday afternoon).  The winds are also shown, indicating southerly winds over the U.S.  southwest and southeasterly (from the s
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A High-Amplitude Atmospheric Wave Threatened Aviation at Sea-Tac Airport

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You would not have wanted to land at Seattle-Tacoma Airport between 2 and 4 AM on Tuesday morning.  (observations shown below) At 1:53 AM, the winds were from the south at 9 knots (10 mph).  At 2:42 AM the winds switched to north-northeast with gusts to 37 knots 9 minutes late (2: 51 AM) the winds turned back to the south, with gusts to 37 knots. At 3:43 AM the winds switched to the northeast at 27 knots At a station near the airport, winds gusted to 63 mph. An aircraft either landing or taking off could have had a dangerous wind reversal and loss of lift.  Fortunately, this is the quietest portion of the day at the airport. The strong winds did result in hundreds of power customers losing power and a number of trees downed. A street scene on Tuesday morning near SeaTac, courtesy of Michael Snyder These strong winds were highly localized near SeaTac (see maximum gusts on Tuesday morning below) The winds were not only localized in space but were short-lived in time, as shown by a plot o
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