Rain Continues Wednesday, Then Another Warmup

FastCast--Wednesday, Oct. 11 to Saturday, Oct. 14:

Rain will continue across Western Washington on Wednesday, with storm totals across the lowlands ranging from 0.4-1.3", most from Everett southward. Highs on Wednesday will be in the mid to upper 50s, with lows in the low 50s. There is a chance of isolated thunderstorms on the coast and in the South Sound on Wednesday as well. Rain will clear out on Thursday, with morning clouds turning to afternoon sun, with highs in the mid 60s. Clouds, and temperatures, will increase on Friday, with highs likely reaching the upper 60s to low 70s. Lows on Thursday and Friday mornings will be in the mid to upper 40s. Showers will return on Saturday, with highs dropping back to the upper 50s to low 60s. With weather systems nearby and abundant clouds, it is unlikely anyone in Washington or Western Oregon will have a good view of the annular solar eclipse on Saturday.

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Rain will continue to move through Western Washington on Wednesday, but a warmup is likely on Thursday and Friday. Let's take a look at the forecast!

We'll start with the European Ensemble forecast (EPS), showing total rain from Tuesday morning to Wednesday night (some has already fallen).

This forecast, which includes rain that fell on Tuesday, gives a total of 0.5-1.4" from Everett southward, with a broad rain shadow on the N/NE side of the Olympic Peninsula. This forecast gives the coast and mountains 1.2-3", and gives areas from Chehalis southward into the Willamette Valley up to 1-1.5". Eastern Washington will be largely rain shadowed, with most areas outside of Douglas County getting 0.1-0.4".

Let's compare this to the GFS forecast, showing rain from midday Tuesday to Wednesday night.

This forecast includes some rain that has fallen on Tuesday, mainly Tuesday morning. The GFS shows less rain for the lowlands, with storm totals of 0.6-0.9" for areas from Everett to Chehalis, 0.8-1.2" from Chehalis southward, and 1-1.5" for the coast and mountains, except up to 2.5" for the southern Cascades. This forecast also shows less rain in Eastern Washington.

Now, let's take a look at the NAM high-resolution forecast, showing rain from Tuesday night to Wednesday night.

This forecast shows that most remaining precipitation will fall from Olympia southward and on the coast. The lowlands could get an additional 0.1-0.4" in this forecast, with the coast and mountains getting 0.5-1" in heavy showers, and areas from Olympia southward getting 0.5-1.2". One thing to keep in mind is that this forecast tends to overdo mountain precipitation amounts, so amounts of 3-5+" aren't likely in the Cascades & Olympics.

Now, let's take a look at temperatures. There will be a considerable warmup by Friday across Washington.

Let's start with the European model forecast for Wednesday's highs, seen below.

On Wednesday, expect highs west of the Cascades in the upper 50s to low 60s. Eastern Washington will reach the low to mid 50s around Spokane to the low to mid 60s in the Columbia Basin.

Temperatures will begin increasing on Thursday, as seen in the European model forecast below.

On Thursday, expect sunnier conditions with lowland and coastal highs increasing to the low to mid 60s. The Willamette Valley will reach the mid to upper 60s, and Eastern Washington will reach the upper 50s to upper 60s.

Friday will be the warmest day west of the Cascades, as more weather systems and cooler conditions will arrive on Saturday. Below is the European model forecast for Friday's highs.

Friday will be a noticeably warm day in the lowlands (but not even close to last Saturday's warmth). Lowland highs will reach the upper 60s to low 70s, with the Willamette Valley reaching the upper 60s to low 70s, the coast reaching the mid to upper 60s, and Eastern Washington reaching the upper 60s to low 70s.

However, as we'll see in the EPS extended forecast below, the warmth will be very short lived. Below is the EPS 15-day temperature forecast for Seattle.

As you can see, Friday stands out as the only 70°+ day in the next 2 weeks. Temperatures will cool dramatically on Saturday, and will likely remain in the upper 50s to low 60s for the foreseeable future. Low temperatures will remain in the low 50s, but could reach the upper 40s at times. Notice that the trend for Seattle is slightly above average high & low temperatures for the foreseeable future.

Let's compare Seattle's forecast to the EPS forecast for Spokane, seen below.

In Spokane, warmth will be limited to Friday and Saturday, with temperatures cooling next week and beyond. Spokane's highs will be below average for most of this week, but will remain slightly above average from Friday onward. Low temperatures are cooler than Seattle, with readings in the upper 30s possible. Lows in the upper 30s to upper 40s are relatively near average for Spokane, with readings in the mid 40s or higher being above average.

Stay tuned to upcoming blog posts for more information about the weather conditions around the Pacific Northwest for the annular solar eclipse on Saturday.

Cool & Rainy Start to the Week

FastCast--Monday, Oct. 9 to Friday, Oct. 13:

After a record-breaking Saturday and cooler Sunday, a return to rainy weather is expected for the Northwest. Showers are expected at times on Monday, with a trace to 0.15" possible across the lowlands. Highs will drop to the low to mid 60s in the lowlands. Tuesday will be much wetter, with totals of 0.5-0.75" expected for the lowlands. It will also be cooler, with highs dropping to the mid to upper 50s. An additional 0.3-0.75" is possible on Wednesday, with highs remaining in the mid to upper 50s. Temperatures will rise with decreasing clouds on Thursday as rain departs the area. Highs will reach the mid 60s, increasing to the upper 60s on Friday, though high clouds are possible. Through the week, expect low temperatures in the mid 40s to low 50s, coldest on Friday morning.

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After a few nice & warm days, rain will return to Western Washington over the next few days, with the most rain on Tuesday and Wednesday. Let's take a look at the forecast!

Let's start with the forecast for total rain through Wednesday night, from the European Ensemble (EPS) forecast.

Through Wednesday night, expect 0.5-1.3" of rain from Everett southward, with 0.4-0.6" from Everett north & west, due to the rain shadow. The Cascades will receive 1-1.5", the Olympics will get 1.5-3", and the coast will get drenched with 2-3" of rain through Wednesday.

Little rain will fall on Monday, with the majority of the rain on Tuesday & Wednesday.

Let's compare this to the GFS forecast, also through Wednesday night.

The GFS shows a similar forecast. It shows a smaller rain shadow (mainly from Port Angeles to Oak Harbor), with the rest of the lowlands getting 0.7-1". The Cascades will get 1-3", the Olympics will get 3-5", and the coast will get 1.5-2.5". As with the EPS, most rain falls on Tuesday & Wednesday.

Now, let's take a look at temperatures. There will be a noticeable cooldown, especially given the record-breaking temperatures on Saturday. Let's start with the European model forecast for Monday's highs.

On Monday, expect lowland highs in the low to mid 60s, coastal highs in the upper 50s to low 60s, Willamette Valley highs in the low to mid 60s, and Eastern Washington's highs in the mid 70s to low 80s, as heat slowly moves east and out of the area.

Noticeable cooling is expected area-wide on Tuesday, as seen in the European model forecast below.

On Tuesday, expect lowland highs to plummet to the upper 50s to low 60s. The coast will reach the mid to upper 50s, the Willamette Valley will reach the low 60s, and Eastern Washington will cool 15-25° to the upper 50s to mid 60s. The mountains will stay cool, with mountain towns remaining in the mid 40s to mid 50s.

Continued cooler weather is expected on Wednesday, as seen in the European model forecast below.

On Wednesday, expect lowland and Willamette Valley highs in the low 60s. The coast will also reach the low 60s, and Eastern Washington will reach the mid 50s near Spokane to the upper 60s near the Tri Cities.

To round out the blog, let's take a look at confidence in precipitation forecasts for Seattle and the coast. Below is the 24-hour precipitation forecast from the European Ensemble (EPS) forecast.

From top to bottom, each left-to-right bar is one of 50 "members" of the ensemble forecast. The dates are across the bottom, with the ensemble mean (most likely forecast) below the dates in the bottom bar. Rule of thumb: if all the members show rain, it'll rain.

This forecast for Seattle shows light rain possible on Monday, with heavier rain on Tuesday and Wednesday, with many ensemble members showing 0.8-1.2" of rain in 24 hours!

Let's compare the Seattle forecast to the Hoquiam forecast, seen below.

The Hoquiam forecast shows more rain overall, with up to 1.5-2.5" of rain in a 24-hour period on Tuesday & Wednesday.

Notice in both the Seattle and Hoquiam forecasts that there are many ensemble members showing heavier rain next week and through mid October...so stay tuned for more updates over the coming days & weeks!

Record Temperatures on Saturday, Pattern Change Ahead

FastCast--Saturday, Oct. 7 to Tuesday, Oct. 10:

After mostly sunny & pleasant days on Thursday and Friday, record-breaking temperatures are ahead for the lowlands on Saturday. Seattle's record of 77° is likely to be broken, with lowland highs in the upper 70s to low 80s (with areas near the water remaining in the low to mid 70s). Mostly sunny conditions will continue on Sunday, with highs dropping to the low to mid 70s. Clouds will return on Monday, with substantial cooling. Highs will drop further to the low to mid 60s, with 0.2-0.4" of rain expected. A stronger weather system is expected on Tuesday, with highs dropping to the upper 50s to low 60s, and 0.4-0.75" of rain likely. Expect overnight lows in the upper 40s to low 50s through Tuesday, and stay tuned for more information on the upcoming pattern change.

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A very warm and potentially record-breaking October day is expected on Saturday, with lowland highs approaching daily records. Let's take a look at the forecast, and the significant cooling expected over the ensuing days.

We'll start with the European model's forecast for highs on Saturday.

On Saturday, expect lowland highs in the upper 70s to low 80s (likely cooler near the water). The Willamette Valley will reach the upper 70s to low 80s, the coast will reach the upper 60s to mid 70s (due to offshore flow), and Eastern Washington will reach the mid to upper 70s.

Scroll to the bottom of the blog to see the power of offshore flow, which brought 80-85° temperatures to the Washington & Oregon coasts...in October!

Next, let's take a look at the GFS forecast, showing highs on Saturday. This forecast often is slightly different from the European model, a good illustration of potential forecast solutions.

The GFS shows a hotter forecast, with the lowlands in the low 80s from Seattle south (isolated mid 80s), and areas from Seattle north in the mid 60s to upper 70s. The GFS shows coastal highs in the mid 60s to mid 70s, Willamette Valley highs in the low to mid 80s, and Eastern Washington's highs in the low 70s to low 80s.

Regardless of exact temperatures, a noticeably hot day is expected for areas west of the Cascades on Saturday. How far above average will Saturday's highs be? Let's take a look at the European model's forecast for temperature departure from average at 2 PM Saturday, seen below.

Temperatures in the lowlands and Willamette Valley will likely be 15-20° above average! That's significant for any time of year, but especially October! Parts of the Coast Range, Cascades, and Cascade foothills could be up to 25° above average.

Let's continue looking at high temperatures for the coming days, as seen below in the European model forecast for Sunday's highs.

On Sunday, expect to notice cooling in the lowlands, with highs dropping to the low to mid 70s. The coast will cool significantly to the upper 50s to mid 60s, with the return of onshore flow. The Willamette Valley will cool to the mid 70s, while Eastern Washington will peak, with highs in the mid 70s to low 80s.

Next, let's take a look at Monday's highs, also from the European model.

Notice major cooling in the lowlands and Willamette Valley on Monday, with highs dropping to the upper 50s to mid 60s. The coast will remain in the upper 50s to low 60s, while a huge contrast will be found by driving across the Cascades. Expect Eastern Washington's highs to remain in the mid 70s to low 80s.

The storm track will return to the Pacific Northwest early next week, with systems on Monday and Tuesday. Let's take a look at expected rainfall, starting with the European EPS forecast through Tuesday night (for some reason, no city values are showing up currently).

The EPS forecast shows 0.5-0.75" for most of the lowlands, with rain shadowing from Everett to the San Juans. The coast and Olympics will get 1-3", with the Cascades getting 0.75-1.5".

We'll compare this to the GFS forecast, also showing total rainfall through Tuesday night.

The GFS forecast shows a similar picture, with 0.5-0.75" for most of the lowlands (with a rain shadow from Whidbey Island to Victoria BC). The coast and Olympics will get 1-3", and the Cascades pick up 0.75-1.5". These forecasts are very similar, but we'll continue watching and comparing over the next few days to see if disagreements develop.

Before we get to Friday's astounding coastal temperatures, let's take a look at the extended forecast for Seattle and Yakima, using the European EPS forecast. We'll start in Seattle, seen below.

In Seattle, expect a hot day on Saturday (highs in the upper 70s-low 80s), with significant cooling to the upper 50s to low 60s for Monday to Thursday. There is a hint of a warmup late next week. Through the extended forecast, highs and lows look to remain above average (except Tuesday & Wednesday's highs).

Let's take a look at the same forecast for Yakima, seen below.

In Yakima, temperatures will be in the 70s through Monday, hottest on Sunday. A cooldown is expected next week, but shorter and to a lesser extent than Seattle. Both forecasts show a potential for another warmup late next week. Yakima's highs and lows will remain above average, except for a brief period to near the middle/end of next week.

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Astounding Coastal Temperatures on Friday!

Friday was a hot day on the Washington & Oregon coasts! Offshore flow (which brings compression and therefore heating of air), brought high temperatures in the upper 70s to mid 80s for areas from Cannon Beach to Forks & La Push! It's relatively rare for the coastal regions to reach the 80°+ mark in summer, but in October!! That is quite rare!