Pacific NW Weather

 Tuesday, April 1st Low pressure remains… North Puget Sound Highs in the upper 40s/low 50s Lows in the low 40s Showers Gusts in the teens South Puget Sound Highs in the low 50s Lows in the upper 30s Showers Gusts in the teens North Willamette Valley Highs in the mid 50s Lows in the upper 30s Showers Gusts in the teens South Willamette Valley Highs in the low 50s Lows in the upper 30s Showers Gusts in the teens Wednesday, April 2nd High pressure tries to fight its way in… North Puget Sound Highs in the low 50s Lows in the upper 30s Showers Little wind South Puget Sound Highs in the low 50s Lows in the upper 30s Showers  Little to no wind  North Willamette Valley Highs in the low 50s Lows in the upper 30s Showers Little to no wind  South Willamette Valley Highs in the low 50s Lows in the mid 30s Showers  Little to no wind

 Update: No longer looking like as steady of rain will occur in the evening, just expect showers in the afternoon and evening. Thanks.

 Sunday, March 30th Another low pressure system begins to dive towards the coast… North Puget Sound Highs in the low to mid 60s Lows in the mid 40s Mostly dry day until a band of rain moves through in the late evening hours Very minuscule chance of a lightning strike with the heavy rain band Gusts in the 30s South Puget Sound  Highs in the low 60s Lows in the low 40s Dry until a band of rain moves through in the evening hours Slight chance of a lightning strike with the heavy rain band, however not very likely  Gusts in the 20s during the rain band North Willamette Valley Highs in the low 60s Lows in the low 40s  Mostly dry until rain moves through around 2 or 3 PM Chance of lightning with the rain band Gusts in the 30s  South Willamette Valley Highs in the upper 50s Lows in the upper 30s Dry until about noon, when a band of rain moves through A couple lightning strikes likely with the rain band Gusts in the upper 30s Monday, March 31st Low pressure remains… Nor...

 Friday, March 28th A low pressure center continues to spin off our coastline… North Puget Sound: Highs in the low 50’s Lows in the low to mid 40’s Mostly steady rain until 3 PM with a few holes in the precipitation. Showers following rest of the day. Gusts in the 20’s South Puget Sound Highs in the low 50’s Lows in the low/mid 40’s  Mostly steady rain with a couple breaks until about 4 PM, heavy showers will follow. Gusts in the upper 20’s North Willamette Valley: Highs in the low 50’s Lows in the low 40’s Steady rain until about 8 AM, heavy showers for the rest of the day Gusts in the low 30’s South Willamette Valley: Highs around 50 degrees  Lows in the upper 30’s Heavy showers all day Gusts in the low 30’s Saturday, March 29th Low pressure continues to hang around the region… North Puget Sound Highs in the low 50’s Lows in the mid 30’s Sparse showers Gusts in the 20’s in the morning and decreasing throughout the day South Puget Sound: Highs in the low to mid 50’s Lows...

 Severe Thunderstorm confidence increasing… Severe thunderstorms are likely to impact portions of western Oregon and Washington tomorrow. To the right is the convective outlook for Wednesday. The “slight” designation across the region is rarely issued in this part of the country, and will likely have severe impacts. The probability of having severe thunderstorms is higher than slight however. Expect frequent lightning, slight chance of 1-2 inch hail, and very gusty winds. Highest chances of severe weather is east of the Puget sound during the late afternoon and evening hours. No tornadoes are expected, however there is a slight chance of some rotation in the strongest cells, and a slim chance of a funnel cloud or two. Heaviest cells will probably become super-cellular. Slight chance of a mini round of showers in the morning before the main event later in the day. Storms will be moving from south to north, moving slightly eastward. The various Storm prediction center outlooks as pub...

 Tuesday, March 25th Ridging stays in control, but over the Pacific, low pressure begins to trek towards the PNW… North Puget Sound: Highs in the mid 60’s, but lower closer to the water Lows in the upper 40’s No rain Little to no wind South Puget Sound Highs in the upper 60’s Lows in the low 50’s No rain Little to no wind North Willamette Valley Highs in the low to mid 70’s Lows in the mid 50’s No rain  Little to no wind South Willamette Valley Highs in the low 70’s Lows in the mid 50’s No rain Little to no wind Wednesday, March 26th Low pressure sets up off the coast, creating a negative tilt in the atmosphere, and some active weather… *Will likely put out another update on Wednesday’s weather tomorrow, as this has potential to be a widespread severe thunderstorm event* North Puget Sound: Highs in the low 70’s Lows in the mid 40’s Slight chance of heavy showers in the morning, and then a break until heavy lines of showers return in the evening Moderate chance of numerous ligh...

  Today’s rain shadow is most certainly occurring. These are rainfall totals since midnight last night. Notice the significantly lower amounts to the east of the Olympics, and the higher amounts across the higher terrain, (see my post on mountainous terrain’s impacts of rainfall totals). Also pictured below is wind gusts today, which should slowly begin to increase.

 Sunday, March 23rd A ridge of high pressure continues to build over the region… North Puget Sound: Highs in the low 50’s Lows in the upper 40’s Steady rain until around noon, with intermittent rain the rest of the day. Potential rain shadow east of the Olympics  Gusts in the 30’s  South Puget Sound Highs in the low to mid 50’s, cooler as you get closer to the sound Lows in the low 50’s Steady rain before 2 PM, becoming intermittent the rest of the day, however, may experience some rain shadow effects Gusts in the 30’s North Willamette Valley Highs in the upper 50’s, possibly reaching the low 60’s Lows in the low 50’s Potential for steady rain starting from 5 to 9 AM, showers later in the day Gusts in the upper 20’s/low 30’s South Willamette Valley: Highs around 60 degrees  Lows in the upper 40’s  Consistent showers in the morning, more scattered in the afternoon hours Gusts in the 20’s Monday, March 24th High pressure persists over the region… North Puget Sound...

 Friday, March 21st Lower pressure continues to persistently stay over the region… North Puget Sound: Highs in the mid to upper 40’s Lows around 40 degrees  Heavy showers starting around 11 AM, lasting the rest of the day Gusts in the low 20’s South Puget Sound: Highs in the mid to upper 40’s Lows in the upper 30’s Showers before 9 AM, and then a mix of steady rain and heavy showers the rest of the day Gusts in the upper 20’s North Willamette Valley: Highs in the low 50’s Lows in the upper 30’s Steady rain all day turning to showers in the evening Gusts in the 30’s South Willamette Valley: Highs in the low 50’s Lows in the low 40’s Steady rain until 6 PM, showers following Gusts in the 30’s Saturday, March 22nd A ridge of high pressure moves into the region… North Puget Sound: Highs in the upper 40’s Lows in the low 40’s Scattered showers until the evening, with slight chance of light rain ensuing. Slight chance of heavy rain later in the night. Gusts in the teens South Puget ...

 The rain that I had previously predicted for today was largely nonexistent. This was due too most of the precipitation evaporating before it reached the surface, (see weather topic on evaporative cooling). As a result of this, precipitation was showing on the radar, but not falling to the ground. Precipitation may start later tonight, but there will not be very much. Also, wind gusts are beginning to increase around the region, largely into the 30’s. Shown on the map are max wind gusts today as of 6 PM, they will continue to increase.

Wednesday, March 19th Our Transient ridge of higher pressure moves out of the region… North Puget Sound: Highs in the upper 40’s to low 50’s Lows in the lower 40’s Light showers from 5 to 8 AM, changing to mostly steady rain for the remainder of the day, with a small break in the precipitation possible around 5 PM Gusts in the 30’s South Puget Sound: Highs in the low to mid 50’s Lows in the upper 30’s to low 40’s Showers starting around 7 AM, turning to steady rain by 10 AM. Possible that a couple hour break in the rain may occur in the evening, but not guaranteed. Gusts increasing throughout the day, getting into the upper 30’s by the evening North Willamette Valley Highs in the mid to upper 50’s Lows around 40 degrees  Steady rain from 9 AM until noon, with a break in the precipitation until around 3 PM, when steady rain returns. Changing to heavy showers around 6 PM. Very slight chance of an isolated lightning strike in the late evening Gusts in the upper 30’s to mid 40’s possib...

 Monday, March 17th Low pressure moves through the region… North Puget Sound:  Highs in the mid to upper 40’s Lows in the mid 30’s, hovering a couple degrees above freezing  Scattered showers in the morning, increasing in frequency in the afternoon hours Outside chance of a lightning strike or two, not very likely Light breeze  South Puget Sound: Highs in the upper 40’s, possibly reaching 50 degrees  Lows in the low to mid 30’s, hovering a degree or two above freezing  Mostly dry in the morning, scattered showers in the afternoon  Slight chance of a lightning strike accompanying the heaviest showers, but not too likely Calm in the morning, gusts increasing into the low 20’s in the afternoon/evening North Willamette Valley: Highs around 50 degrees  Lows in the mid 30’s Heavy showers starting around noon, lasting the rest of the day Outside chance of a lightning strike Gusts increasing into the the teens South Willamette Valley: Highs in the upper 4...

 Models have begun to show the steady rain I mentioned in the forecast arriving later today than expected. Below are the new approximate times that the weather will change from showery to constant. South Willamette Valley: 1 PM North Willamette Valley: 3 PM South Puget Sound: 8 PM North Puget Sound: 11 PM As a side note here is some data from so far today:                                                                                                                     Precipitation Totals                                       Max wind gusts (will continue to increase)         ...

 Saturday, March 15th An atmospheric river will be pointed at the Oregon Coast, bringing active weather… North Puget Sound: Highs in the upper 40’s, with temperatures temporarily dropping during the heaviest showers. Lows around 40 degrees  Showers all day, with a particularly strong band possible around 9 AM. Changing to steady rain around 8 PM. Chance of scattered lightning strikes, particularly in the early afternoon. Gusts in the 20’s South Puget Sound Highs in the mid 40’s, with temperatures dropping during heavy showers. Lows in the upper 30’s Heavy showers all day until steady rain returns around 2:30 PM, lasting the rest of the day. Scattered fairly weak thunderstorms Gusts in the upper 30’s, and maybe even reaching up to 40 until around noon. Gusts in the 20’s for the remainder of the day. North Willamette Valley: Highs in the mid to upper 40’s Lows in the upper 30’s Dense heavy showers until steady rain returns around 1 PM, changing back to showers around 8 PM Scatte...

 Thursday, March 13th An area of lower pressure will move inland… North Puget Sound: Highs in the low to mid 40’s turning colder in the afternoon due to heavy showers Lows in the mid 30’s Steady rain in the morning hours, ending by 6 AM, and then heavy showers beginning around 9 AM lasting the rest of the day. Slight chance of some snowflakes mixing in for the higher hilltops during the heaviest showers. No accumulations expected. Scattered thunderstorms in the evening and nighttime hours Gusts in the 20’s South Puget Sound Highs in the low 40’s with temperatures dropping locally into the upper 30’s during heavy showers Lows in the mid 30’s Steady rain ending around 5 AM, with scattered heavy showers following that the rest of the day. Chance of some snowflakes mixing in during the heaviest showers, especially in the later evening. Very small to no accumulations expected.  Scattered thunderstorms  Gusts in the 20’s North Willamette Valley: Highs in the mid 40’s Lows in th...

 Mountainous terrain and its impact on Precipitation totals Impact #1 Yearly, the Western slopes of the Cascade mountain range receives up to 50 inches more rainfall than the Puget sound region. Why is this? This is due to its terrain features, and proximity to large bodies of water. As warm, moist air at the surface moves over the Puget sound region, it is forced to rise upwards as it smacks into the western slopes of the Cascades. This causes the relatively moist air to condense and change from a vapor to a liquid/solid during its path as an upslope wind climbing in order to get over the cascades. It condenses because as it is forced upwards, it enters cooler air, and freezes. This extra liquid falls in very heavy downpours, and has mostly all fallen by the time it reaches the Cascade crest. This phenomenon is known as Orographic lifting .  Impact #2 The second impact of mountainous terrain is an effect of orographic lifting, and it is the rain shadow effect. The rain shadow...

 Tuesday, March 11th A low will drop down from the gulf of Alaska, and begin to push toward the region… North Puget sound: Highs in the upper 40’s Lows in the lower 40’s Showers starting around 6 AM, lasting till noon. Steady precipitation beginning around 4 PM, lasting the remainder of the day Gusts in the 20’s with maybe a gust up towards 30 in the evening hours South Puget sound: Highs around 50 degrees Lows in the low to mid 40’s Rain starting around 3 PM, continuing for the rest of the day  Gusts in the 20’s, maybe low 30’s North Willamette valley Highs around 50 degrees Lows in the mid 40’s Showers starting around noon, transitioning to steady rain by 3 PM Gusts in the upper 20’s South Willamette valley Highs around 50 degrees Lows Lows in the low 40’s Rain starting around 5 PM, lasting the remainder of the day Gusts in the 20’s Wednesday, March 12th Our low pressure system moves in towards our coastline… North Puget sound: Highs in the upper 40’s Lows in the upper 30’s ...

 Today may not be a large wind maker, but it may catch a few people by surprise. Winds are looking like they will build to around 30-40 MPH for the south and central Puget sound, with higher gusts on the coast, Whidbey island, and portions of the San Juans. Gusts are already increasing, as shown by the recorded wind gusts as of 11 AM on the right. Gusts around 50 have already begun around the northwest interior, as shown. The atmospheric river is currently sliding south as seen on the following satellite imagery below (College of DuPage). The pressure gradient preceding this is what is causing these medium force winds. As these winds will not be too strong, no significant damage is expected.

 Sunday, March 9th The remnants of the atmospheric river will sag south, as higher pressure moves out… North Puget Sound: Temps in the mid upper 40’s before noon, and then dropping into the low 40’s in the afternoon hours Lows around 40 Potential for light showers around 6 AM, followed by a break in precipitation and then steady rain will begin around noon, lasting until 9 PM, and that will be followed by showers Gusts in the 40’s in the morning, dropping to the 20’s in the afternoon  Slight chance of a lightning strike or two in the evening South Puget Sound: Temps in the mid 50’s before 3 PM, then dropping into the low 40’s Lows in the mid to upper 30’s Rain starting around 1:30 in the afternoon, ending by 11 PM Gusts in the mid 30’s North Willamette Valley: Highs in the mid to upper 50’s Lows in the upper 30’s Rain starting around 6 PM, ending by 3 AM Gusts 20-30 MPH South Willamette Valley: Highs Around 60 degrees Lows in the low 40’s Rain starting around 10 PM Gusts in th...

 Friday, March 7th A ridge of high pressure moves into the region… North Puget Sound:  Highs around 50 Lows in the mid 40’s No precipitation throughout the day, however, may start in the late evening to nighttime hours Gusts 10-20 MPH South Puget Sound Highs in the low 50’s Lows in the upper 30’s Possibly a shower or two after 8PM, not too much rain Gusts in the low teens North Willamette Valley: Highs in the mid 50’s Lows in the mid to upper 30’s No precipitation  Very slight breeze, nothing more South Willamette Valley  Highs in the mid 50’s Lows in the mid 30’s No precipitation  Very slight breeze Saturday, March 8th High pressure begins to move out of the region, and spotty rains return for some… North Puget Sound:  Highs in the low 50’s Lows in the mid 40’s Precipitation in the early morning hours ending by around 8 AM and then rain potential will resume in the afternoon hours Gusts ranging from 10-40 MPH  South Puget Sound Highs in the mid 50’s L...

 Snow in the Puget sound lowlands Section 1: Why it is hard to get Puget sound snow Sometimes in the Puget sound lowlands, we can go very long periods of time without snowfall, even during winter. This is because of multiple terrain features that are nearby, and these features make it very difficult to get cold air down to surface level at lower elevations. The first of these features is the Puget Sound itself. Water is a temperature moderator, because it stays at a relatively stable temperature. Due to this, typically the further you get from a large body of water, the more variability there is in temperature. A personal experience of this phenomena taking place was when I drove from the Tacoma area to Portland. It was 36 degrees and raining by the Puget sound in Tacoma, but during the portion of the drive just south of Chehalis, the temperature dropped to 29 degrees, and heavy snow was falling. This was because Chehalis was further from a large body of water to act as a moderator...

 Tuesday, March 4th In the afternoon, low pressure will move ashore… North Puget sound: Highs in the upper 40’s Lows around 40 A front will move through bringing rain from about 10AM to noon, with showers following that event Gusts 20-30 MPH South Puget sound: Highs in the upper 40’s Lows in the upper 30’s Front will bring rain from about 9 AM to around 2 PM, with showers following Gusts 10-25 MPH North Willamette Valley: Highs around 50 Lows in the mid to upper 30’s Weak front with rain from about 8 AM to 1 PM, with showers following that Gusts around 20 MPH South Willamette Valley:  Highs in the upper 40’s Lows in the low 40’s A weak front will bring rain from 7-11 AM, with showers following after Gusts 10-20 MPH Wednesday, March 5 Low pressure hangs around the PNW… North Puget Sound: Highs in the upper 40’s to low 50’s Lows in the low 40’s by the sound, dropping to the low 30’s as you go inland  Possibly some light showers in the early afternoon hours Little to no wind...

 Sunday, March 2nd An area of low pressure will be moving over the Oregon region… North Puget sound: Highs in the upper 40’s, lows in the mid 40’s, very little to no rain, wind up to 10 MPH, maybe a little fog, but shouldn’t be too much. South Puget sound: Highs in the mid 40’s, lows in the low 40’s, Showery precipitation, mainly south of federal way, spotty dense fog. North Willamette valley: Highs around 50, lows in the low to mid 40’s, Steady precipitation in the morning hours ending before dawn and then showers resuming by 2-3 PM, spotty medium level fog. South Willamette valley: Highs in the mid 40’s, lows in the low 40’s to upper 30’s, steady rain before 3AM with rain lingering longer on the coast before showers resume by 1-2 PM, spotty fog. Monday, March 3rd A band of high pressure returns over the area…  North Puget Sound:  Highs around 50, lows in the low 40’s, possibly a few showers, spotty fog in the morning hours. South Puget Sound: Highs around 50, lows in th...