Tag Archives: Rainfall

Kitsap weather shifts to unusual patterns over past three months

“Average, very average.” That’s how things were going for the first quarter of Water Year 2019, which began in October and ran through the end of last year (Water Ways, Jan. 4). But the second quarter, which began in January, presented an uncharacteristic upheaval, as various portions of the Kitsap Peninsula went their own way.

We’ve talked before about how Southwest Kitsap typically has twice the rainfall as North Kitsap. But even the patterns of rainfall have been different the past three months, and you can’t compare these areas to anywhere else. Let’s take them one at a time:

Hansville: Representing the north end of the peninsula, Hansville received 2.5 inches of precipitation in January, well below the 4.4-inch average for the month. February followed with a little below average, 2.8 compared to 3.2 inches. Like January, March was quite low, with 1.1 inches compared to a 3.5-inch average. In the first chart (click to enlarge), you can see this water year’s rainfall total (blue line) slipping below average (pink line).

Silverdale: Representing Central Kitsap, Silverdale received 5.9 inches of rain in January, somewhat below the 7.2-inch average. The gap widened in February, when 3.4 inches of rain fell — below the average 4.9 inches. In March, the 0.8 inches of precipitation was even below dry Hansville’s 1.1 inches and way below 5.6 inches — the March average for Silverdale. In the second chart (click to enlarge), this water year’s rainfall has fallen below the average (pink line) and even below last year’s below-average precipitation (orange line).

Holly: Representing Southwest Kitsap, Holly was about average for January, with 11.6 inches of rain compared to an average of 12.8. But if the gap was wide between February’s rainfall and the monthly average in Silverdale, it was wider in Holly, where the 4.2 inches of rainfall was just half of the 8.3-inch monthly average. And rainy Holly just about dried up in March, when the area seemed more like the north end during a drought. The 1.2 inches of precipitation that fell on Holly in March was just 13 percent of the average 9.1-inches. The chart (click to enlarge) shows the drop from about average to well below average in just two months.

I can’t easily describe the mixed pattern across the Kitsap Peninsula, but the lack of rainfall is part of an overall picture for Western Washington, which has been officially declared “abnormally dry” on the Drought Monitor managed by the Natural Resources Conservation Service. As you can see on the map, the entire region was below 50 percent of average rainfall for March.

The drought picture could change quickly with anticipated April showers — actually RAIN — that should arrive late tonight or tomorrow morning throughout the region, according to the latest forecast by the National Weather Service. Rain is expected through Saturday, when the weather changes to mostly cloudy with a continuing chance of showers through next Tuesday.

Weak El Nino conditions are expected to continue in our area throughout the spring and into summer, bringing warmer- and drier-than-average conditions to the Northwest, according to the National Oceanic and Atmospheric Administration’s ENSO Adviser and the State Climatologist’s Office.

The word is ‘average’ for the first three months of Water Year 2019

Average, very average. That was my first reaction as I looked over the rainfall data for the first quarter of Water Year 2019, which began Oct. 1.

The point was driven home when I looked at the rainfall totals for Silverdale on the website of the Kitsap Public Utility District. October’s rainfall total was 3.23 inches, compared to a median average of 3.74 inches. November’s total was 5.51, compared to a 6.83 average. And December’s total was 9.31, lining up perfectly with a 9.31 average. (Exactly the same! What’s the chance of that happening?)

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Hansville sees record rains coming down during November

Hansville is the driest area in Kitsap County, but in November the skies opened up with more rain than we’ve seen there in the past 27 years. In November, enough rain fell in Hansville — 8.7 inches — to break the record for that location.

Hansville // Graphic: Kitsap PUD

Longtime residents of our region realize that the amount of precipitation goes up dramatically as one travels south out of Hansville. For Silverdale, November 2017 was the sixth wettest November in 26 years, with a total of 11.0 inches. Holly experienced its fourth wettest November, with 22.9 inches, all based on rainfall data compiled by Kitsap Public Utility District.

The one glitch for Hansville is that three years of rainfall data are missing — specifically 2007, 2008 and 2009 — and 2007 was a particularly wet year in some parts of the county. In fact, record November rains were seen in 2007 in Holly but not in Silverdale. We may never know where 2007 would have fit into the records for Hansville, but November 2007 was only average in Port Gamble — the closest station. It’s very likely that Hansville really did break the record for November this year.

Silverdale // Graphic: Kitsap PUD

Consistent with those geographic differences, in Holly it rained 27 out of 30 days in November, compared to Silverdale with 22 out of 30 days and Hansville with 20 out of 30 days. This came after a fairly average October.

As you can see from the charts on this page, November rains pushed the lines up to begin tracking the wettest years in the record books from one end of the county to the other. But, as I discussed last month, anything can happen during the coming winter and summer. Last year started out well ahead of the wettest years on record. But, starting in mid-December, the rains did not keep pace with the record years, and then came a very dry summer. See Water Ways, Oct. 27.

Holly // Graphic: Kitsap PUD

Let me take a moment to further emphasize the difference in rainfall from north to south on the Kitsap Peninsula. Holly’s nonrecord precipitation of 22.9 inches in November is more than half of Hansville’s rainfall for the entire record year of 1999, when a total of 43.8 inches came down. Holly’s annual record is 127.5 inches set in 1999.

The average annual rainfall for Hansville is 30.7 inches, compared to Silverdale with a 42.8-inch average and Holly with 79.2 inches.

Looking forward, the rains are likely to continue, according to NOAA’s Climate Prediction Center (PDF 5.3 mb). La Nina conditions emerged in October and are predicted to continue through the winter in the Northern Hemisphere. The likely result will be below-average temperatures and above-average precipitation across the northern part of the contiguous U.S. — and the opposite across the southern tier of states, as shown in the map below.

Green shows above average precipitation; brown is below average.
Graphic: National Climate Prediction Center