Monday, December 31, 2012

Friday, December 28, 2012

Thursday, December 27, 2012

Monday, December 24, 2012

Christmas 2012 Storm

Windy over Eastern Lowlands (Black Diamond, etc). Snow SE of Olympia, light snow possible around Seattle in the morning.

Friday, December 21, 2012

Thursday, December 20, 2012

Water Level Recently

Extreme high tide + low pressure system = high water levels. Global warming not really involved at this point.

Sunday, December 16, 2012

Very Windy Storm Coming

Sunday night through Monday afternoon, 40-60 mph winds possible in the SW of Washington. High winds will come to Seattle throughout the day. Be careful!

Saturday, December 15, 2012

Windy on Monday

It will be windy in Bellingham Sunday night & in the Puget Sound on Monday. 30-40 sustained.

Friday, December 14, 2012

Cliff Mass Lost His Calendar

Cliff Mass has been reading history books again. Turns out it was wet in 1805. Still is. Go figure.

Wednesday, December 12, 2012

Monday, December 10, 2012

NWS Revamping

The NWS is broken & needs to be fixed. Lots of problems, big issue, long hard path to success.

Thursday, December 6, 2012

Tuesday, December 4, 2012

Rain Reality

It rains roughly 15-20% of the time during the winter in Seattle if you count at the hourly level.

Saturday, December 1, 2012

Smartphone Observations

Smartphones enable more observations. More observations enable better forecasts. Hurray!

Friday, November 30, 2012

Heavy rain in CA and snow in mountains

Its going to rain a lot in California & most of the Cascades will get a foot or more of snow.

Tuesday, November 27, 2012

Windy, Rainy, but no Snow

Its going to get windy on Wednesday & a little wet, but more south of us. Too warm for snow unless you get to BakerCrystalWhistler level height.

Sunday, November 25, 2012


Rainbows often have secondary rainbows. Sometimes they have reflective rainbows as well! Reader found one:

Friday, November 23, 2012

Technology May Reduce Accidents

Technology can warn when rain, smoke, dust, or other conditions may impact busy freeways, helping to prevent accidents.

Wednesday, November 21, 2012

Convective Cloud

A convective cloud line came through Seattle at 1:30PM on Tuesday, bringing a dark rain patch that faded quickly to sun.

Tuesday, November 20, 2012

High Winds on Coast

High winds on the coasts of WA & OR were seen during the Monday storm. Forecast for Thanksgiving looks decent & Friday outlook is improving, but still wet.

Monday, November 19, 2012

Heavy Rains

Very heavy rains Monday morning. We've already had close to 2" over the city in the last 48 hours, many rivers are at flood stage already, & the rain is not going away. Be careful.

Sunday, November 18, 2012

Rain shadows we have

Depending on where the rainfall comes from, at least one local area is usually in a fairly deep rain shadow.

Rain Sunday Monday Friday

Heavy rains on Sunday & Monday. Rainy all week. Bigger storm possible Thursday or Friday. Flood conditions possible, be prepared & stay alert.

Thursday, November 15, 2012

Monday, November 12, 2012

Improvements Past and Present

Hurricane Sandy proves we have improved a lot in forecasting ability. We can still do much better.

Sunday, November 11, 2012

Saturday Cold Sunday Rain

It got really cold Saturday. Sunday warmed up so we get rain not snow. Cliff Mass studied under Carl Sagan, helping CM learn how important public communication of science is.

Wednesday, November 7, 2012

Winter 2012 La Nada

Winter 2012 looks to be La Nada (neither El Nino or La Nina). La Nada tends to yield bigger storms. Seattle has made great strides, including road temperature sensors. We still can't predict snow well.

Monday, November 5, 2012

Stampede Pass Weather Station

NWS is considering closing the Stampede Pass weather station. It has great observational value & a long record in that location. Contact Dr. Brad Colman ( to urge NWS to keep it.

Saturday, November 3, 2012

Another Storm for the NE

Wednesday & Thursday, another storm will bring strong winds, heavy rain, & inland snow to the Northeast. It is not currently expected to be a hurricane, but sustained winds of 40-50 knots are expected.

Tuesday, October 30, 2012

Drought No More My Son

We have almost completely made up the rainfall deficit of this summer in the last 2 weeks. Be careful, river flooding is possible.

Sunday, October 28, 2012

Hurricane Sandy III

Hurricanes are powered by a warm core of air. Midlatitude storms are powered by a cold core of air. Monday night, Hurricane Sandy will transition to a cold core.

Friday, October 26, 2012

Hurricane Sandy II

Hurricane Sandy is shaping up to be quite a storm. Many models are converging to show Sandy making landfall in New England on Tuesday. Very dangerous - pay attention to the forecasts if you're going anywhere near the East Coast next week.

Wednesday, October 24, 2012

Hurricane Sandy

Some models suggest Hurricane Sandy will make landfall in New England. Some don't. Be prepared.

Monday, October 22, 2012

El Nino No More

Forecast is for neutral ENSO year. Higher odds for severe windstorms, snowstorms, floods - be prepared.

Sunday, October 21, 2012

Water Funnels

Very nice photos of water funnel near Everett, thanks to Chris Evans. The funnels were apparent on radar between 4 & 4:15PM.

Friday, October 19, 2012

Wednesday, October 17, 2012

Tuesday, October 16, 2012

Sunday, October 14, 2012

Its Raining

Its finally raining and the radar is impressive. This week is expected to be more normal weather for this time of year - rainy and windy. Probably not as much rain as this weekend.

Wednesday, October 10, 2012

50th Anniversary of Columbus Day Storm

In 1962 there was a massive storm. Likely the biggest cyclone to hit the lower-48 this century. It was really, really windy, damaging, & 46 people died.

Monday, October 8, 2012

Saturday, October 6, 2012

Friday, October 5, 2012

Debate Weather

Atmospheric pressure probably didn't affect Obama. Big temperature drop occurred during debate. Related? [TLDR Editor - I almost didn't bother with this one...]

Thursday, October 4, 2012

First Cold Front

Cold front came through. It got cold. August-September was the driest on record at Seatac.

Tuesday, October 2, 2012


Winds from the N & NW are blowing the smoke from the fires to the east away from us, increasing visibility. Really impressive change in the photos of Rainier from a local webcam (images are 4 days apart).

Saturday, September 29, 2012

Weak El Nino Sort Of

It looks to be a weak El Nino year. Probably slightly warmer, drier, and milder. Very close to normal though.

Wednesday, September 26, 2012

Dry and slightly colder

It has been dry. It will stay dry (for a few weeks, barring minor sprinkles). Its getting colder with longer nights. Yawn.

Friday, September 21, 2012

Fire not Drought

Air quality is bad near Wenatchee. Also, we're not in a drought as the cumulative precipitation for the year is actually slightly above normal.

Wednesday, September 19, 2012

Still dry

If we're more lenient in what counts as "rain" (0.01" to 0.02") we are now breaking a record. Its still dry. No, really.

Monday, September 17, 2012

Smoke but not Russian

Smoke from fires east of Seattle is affecting Seattle. Russian fires aren't affecting us anymore.

Saturday, September 15, 2012

Smoke cools and warms

During the day, smoke blocks solar radiation from reaching the surface, cooling things below it. At night, it acts as an insulating layer, warming things below it.

Friday, September 14, 2012

Wind moves smoke

This just in, wind can move smoke. Winds from Eastern Washington move smoke from fires there to Western Washington.

Wednesday, September 12, 2012

Super Mirages

Super mirage - objects near surface are raised or stretched. Caused by temperature inversion (warm over cold). We have cold water & warm air (sometimes). Thus, we have super mirages.

Monday, September 10, 2012

Saturday, September 8, 2012

Rain cometh

Sunday night will break the dry streak, short of 51 days. Careful driving Sunday PM / Monday AM - oil from roads mixed with rain = dangerous.

Tuesday, September 4, 2012

Dry Spells

Longest ever dry-spell for Seatac is 51 days. We're at 45. Expected to at least make 48, making 2nd place. 52 is entirely possible. Cliff is excited.

Monday, September 3, 2012

Olga 2E

Olga 2E is a weather data point active for 122 years. It shows slight warming in the minimum temperatures, probably PDO related.

Friday, August 31, 2012

Dry August

Probably the driest August ever. Ever. Less than 0.01" of precipitation. Probably dry for 4-7 days & warming.

Monday, August 27, 2012

Sunday, August 26, 2012

First Frost And Isaac

Some areas saw first frost last night, mostly higher elevations east of the Cascades. Isaac will mostly miss Tampa & land along Gulf shoreline.

Friday, August 24, 2012

Urbanization of Temperature Sites

Urbanization leads to inconsistent temperature readings (Seatac is showing warmer than it probably is).

Wednesday, August 22, 2012

Warmer Water Offshore

Wind keeps warm southern water south, Coriolis force pushes water out to sea & cold water comes up to replace it. Also, survey!

Tuesday, August 21, 2012

Dry but not drought

It has been dry but we are not in a drought. It should be colder and drier than normal for the next 7-10 days.

Saturday, August 18, 2012

Friday, August 17, 2012

More Wildfires Possible

After heat wave come possible thunderstorms with lightning but little surface rain, followed by high winds. Be prepared!

Wednesday, August 15, 2012

Tuesday, August 14, 2012

Winds down heat up

Winds plaguing fire fighters east of the Cascades should die down as the heat wave arrives overnight.

Sunday, August 12, 2012

Lost Cats in Heat

Warm weather correlates with more cats at shelters.

Announcement: Columbus Day Storm 50th Anniversary Gala at the UW: Oct. 11, 7:30 PM

Friday, August 10, 2012

Thursday, August 9, 2012

Recent News Makes Cliff Mad

James Hansen published a study that Cliff Mass feels misrepresents the data & the story. Cliff sees global warming happening but sees most of the cause of extreme events as natural variation. Rabble rabble rabble.

Wednesday, August 8, 2012

Awesome Clouds

There was a neat mammatus cloud system visible from across much of the state. The underside of the cloud showed the upside-down convection effect (mammatus).

Monday, August 6, 2012

Line of Clouds

The thermal trough moving on, heat wave ending. East-West trough moving north causing line of clouds & mid-level convection. Rainfall not reaching ground due to earlier heat. No heat wave next weekend.

Saturday, August 4, 2012

Algebra is Important

Algebra is important. Kids failing it does not mean they don't need it, but that we should teach it better.

Friday, August 3, 2012

Its going to get hot

High pressure from the south, then offshore flow, lots of warmth that builds over the next few days. Mid 80s, maybe 90s.

Tuesday, July 31, 2012

Boring Weather

Summer weather on the west coast is boring due to static ocean temperatures & jetstream aiming elsewhere.

Sunday, July 29, 2012

Careful what you claim

Recent extreme weather is just that - extreme weather. Natural variation in weather is far more likely to be the cause than global warming. Future issues (think century scale) will be linked to global warming, which is a serious issue to be addressed.

Monday, July 23, 2012

Saturday, July 21, 2012

Lots of Rain

Seattle got more rain Thursday/Friday than a normal July from a deep trough pulling tropical moisture up to us. Closed low settling in for cooler but still wet weather Sunday/Monday.

Thursday, July 19, 2012

Thunderstorms and Flash Floods

Lots of thunderstorms & a few flash floods lately. Flash flood watch for much of Eastern Washington. Be careful!

Wednesday, July 18, 2012

Lightning is dangerous

Stay safe around lightning! Stay inside away from plumbing & electronics. Stay in car. If outside, find low spot, crouch (don't lay down!), cover ears. Be careful!

Sunday, July 15, 2012

Texas Global Warming Article Problems

Recent study of 2011 Texas heat wave/drought is flawed but produces hyperbolic media statements on global warming, reducing scientific credibility.

Friday, July 13, 2012

Its called Thunder apparently

Low pressure system over Olympia blocked onshore flow (which kills thunderstorms here). Thus, thunderstorms!
Image shows recent tweets referencing thunder in our area (by UW Atmospheric Sciences Grad Student Luke Madaus)

Monday, July 9, 2012

Friday, July 6, 2012

Wednesday, July 4, 2012

Wet Past Dry Future

Tuesday was weird. Otherwise NW has been more wet than normal, soil has been more wet, & that keeps us cooler and more humid longer.

Monday, July 2, 2012

Thursday, June 28, 2012

Wet and cold

It's been colder than normal here due to a trough over the eastern Pacific and a ridge over the rockies (atmospheric in both cases). 4th should be overcast / showers & mild temperatures.

Tuesday, June 26, 2012

Melting Snow

Mountain snowpacks are melting later lately. Global warming is occurring but our region isn't as strongly affected, yet.

Change in winter temperature from 1980 to now.

Saturday, June 23, 2012

Rain rain rain

It rained a lot. Some records were broken. It rained more towards Portland. Less rain tomorrow.

Lots of Rain

Very strong low pressure for this time of year causes lots of rain in unpredictable distribution.

We Do Need Some Education

Discovery math is bad. Singapore or Saxon math is good. We can make the switch if we push hard.

Cold Water Along Coasts

Winds from the north & the coriolis effect push surface water away from the coast, bringing cold water up from below.

Wednesday, June 13, 2012

June Gloom

The cloud cover in June affects most of the Pacific & West Coast. Get 3-5K' above ground or east of Cascades to avoid.

Monday, June 11, 2012

NWS Troubles

The NWS used funds to cover things without getting permission. Some people retired. No real scandal beyond the underfunding of the NWS.

Sunday, June 10, 2012

Seasonal rainfall patterns

It rains in different seasonal patterns in different regions of the US due to the jet stream. Specifically:
West Coast - 80+% of rain from October to March
Eastern Montana and North Midwest - 50+% of rain from April to June
Inland Southwest - 50+% of rain from July to August
East Coast - Almost uniform rain amounts year round

Friday, June 8, 2012

Wednesday, June 6, 2012

Clouds Inland

Rising air tends to cause clouds. Cold air off water hits sun-warmed air over land & rises. Strong offshore winds hit slow air over land & rises. Air hits hills & mountains & rises. Thus clouds inland.

Tuesday, June 5, 2012

Venus Transit Final

Head to the coast to see Venus's transit. Downstream of Vancouver Island mountains or Olympia & beyond.

Monday, June 4, 2012

Saturday, June 2, 2012

Coal Trains

Coal trains produce coal dust in transit, worsen anthropogenic global warming, & send pollution from Asia to the NW. Just say no!

Tuesday, May 29, 2012

Forecasting Skill

Forecasting skill - 2-3 days - excellent | 3-4 d - moderate but useful | 5-6 d - marginal | 7-10 d - occasional

Sunday, May 27, 2012

Saturday, May 26, 2012

Friday, May 25, 2012

Ellensburg Winds

Ellensburg has strong winds due to Snoqualmie Pass & high pressure ridges in the west. Fri/Sat sunny 60s. Sun/Mon overcast sprinkles 60.

Wednesday, May 23, 2012

Monday, May 21, 2012

Saturday, May 19, 2012

Clouds block annular eclipse

High chance of clouds blocking views of annualar eclipse in the NW. Views would have been partial as we're too far north.

Sunday, May 13, 2012

Large Temperature Swings

Clear skies, no-to-light winds, and compressional heating lead to large mood temperature swings in the NW this weekend.

Friday, May 11, 2012

Wednesday, May 9, 2012

Windy Coastal Oregon

Southern Oregon (Brookings) / northern California (San Francisco) coast often has 30mph sustained winds during the warm season due to pressure & temperature differentials.

Monday, May 7, 2012

Surface Temperature <> Air Temperature

Surface temperature can be up to 40 degrees F warmer than air temperature. Seeds require specific temperatures to grow.

Saturday, May 5, 2012

Return of the Warmth

Sunday - warm & sunny. Monday - more so - high in 70s. We had large convergence zones recently.

Wednesday, May 2, 2012

Monday, April 30, 2012

Unanswered Questions

Funnel clouds appear in Skagit County around April (explanation missing from original post). Monday, April 30th was windy.

Tuesday, April 24, 2012

Monday, April 23, 2012

Let's not overreact

Manmade climate change is not causing the extreme weather of late (but will likely cause extreme weather in the latter half of this century).

Wednesday, April 18, 2012

Monday, April 16, 2012

Wednesday, April 11, 2012

Monday, April 9, 2012

Might be warmer...

It's been warm lately & might continue some. This weekend should be good for hiking east of the Cascades.

Thursday, April 5, 2012

Big Cloud Action

Big cloud action due to large temperature difference between ground & sky. 40 years ago (1972) - F3 tornado in Vancouver, WA.

Tuesday, April 3, 2012

Crossover - Like Passover for Weather?

Sometimes its warmer west of the Cascades (winter). Sometimes its not (late spring, summer, fall). This is Crossover! Also, east of the Cascades there are fun things to do (if you don't mind the lack of trees).

Friday, March 30, 2012

It rained. A lot. More to come.

Record rainfall east of Cascades & greater than normal elsewhere. Late Monday / early Tuesday are going to be very wet. Lots of water vapor headed our way over Pacific (see image). Support public radio.

Wednesday, March 28, 2012

Tuesday, March 27, 2012

More Sun (with caveats)

Big jump in sun from January-March, slower increase to July peak. Clouds interfere, but we do alright for our latitude.

Handing over the rains

Starting today, I'm handing over the reins to a new TLDR'er, Ben. Just one of dozens of applicants, Ben passed a very rigorous screening process. So I leave you in good hands.

Ben is a local mathematician who knows a bit about forecasting (energy use, not weather) and follows the weather as a hobby. He loves big storms (snowy and otherwise), enjoys German board games, roughhousing with his dogs, and enjoying life with his partner, Kim.

Everybody set aside your Seattle Freeze for a minute and give Ben a warm welcome. If he does things right (which I'm sure he will), this will be the longest post on the blog for a while.

Sunday, March 25, 2012

Does someone want to take over this blog for me?

CliffMassTLDR got a little too busy to handle his duties as TLDRifier. Anyone want to take over this blog? Low wages, bitter cold, long hours of complete darkness. Safe return doubtful. Honor and recognition in event of success.

Thursday, February 23, 2012

Rainy lake

Some lake north of Gold Bar got lots of rain.

In other snowy news, there's an enhanced chance of light snow in some lowland locations on Sunday. No big storm though.

Wednesday, February 22, 2012

Snow less likely

It will get cold over the weekend, but a major lowland snow event does not look likely. Lots of snow in the mountains, so play it safe up there.

Monday, February 20, 2012

Snow over the weekend?

There's a good chance we'll get colder temps at the end of the week, but we must wait a few days to have a good idea what will happen. Lowland snow is a possibility, but far from certain.

Thursday, February 16, 2012

Prediction for spring

Now that all those prognosticating animals are done, let's look at what the prognosticating scientists have to say.

Spring is predicted to be warmer than normal for the Northwest, making this a far better spring than the last two years.

Tuesday, February 7, 2012

Thursday, February 2, 2012

Animals predict the weather

The frog predicts good NW weather for the rest of the winter. The hog predicts 6 more weeks of winter on the East Coast.

I agree with both animals.

Friday, January 27, 2012

Where weather data comes from

We get the most weather data from weather satellites, but also from weather buoys, commercial ships, and airplanes.

Forecasts have become much more accurate over the past few decades. This chart shows how much (higher "anomaly correction" = better forecasts):

Wednesday, January 25, 2012

Napavine = Weird

Napavine, WA (just south of Chehalis) has some weird weather:

  • 25.5 in. of snow last week
  • the only place in western Washington to be hit by a tornado last year
  • experienced flooding that closed the nearby Interstate for days
  • the warmest temperatures in western Washington during the July 09 heat wave (114F)

Speaking of weird, check out what last week's winds did to some waterfront homes in Oregon:

Monday, January 23, 2012

Saturday, January 21, 2012

Friday, January 20, 2012

It's over...for now

Warmer temperatures today. But forecast models for next week indicate some heavy rains, strong windstorms, and the arrival of frigid arctic air...

Thursday, January 19, 2012

Oops I accidentally the weather

I forecasted a little freezing drizzle in the South, not that the precipitation would move so far north, so fast. We have several hours more of this snow/sleet/freezing rain event. By tomorrow morning, there should be warmer temps.

Freezing rain/sleet storm

In case you haven't noticed, we're having a rare freezing rain/sleet storm everywhere south of Everett. It's caused by a temperature inversion near the surface, where warm air pushes up above a sub-freezing air mass. Some of this rain is freezing on the way down into ice pellets (sleet), but a lot of it is staying liquid and hitting the ground as freezing rain (freezes on contact with the cold surface).

Today there will be a wintry potpourri: freezing rain, sleet, snow, and rain, until the air warms up enough to turn it all into rain.

Wednesday, January 18, 2012

Sn'over by 1PM

It's gonna stop snowing around 1PM. More snow tomorrow, but only for Olympia and south. Rain and warmer on Friday, washing the snow away.

Tuesday, January 17, 2012

Meet our new weatherman

Mr Spock, please hold up fingers to show us how many inches of snow there will be tomorrow:


Newer, more reliable weather models agreeing with the "less snowfall" prediction. Stay tuned for more detail after 9pm tonight.

Less snow predicted for tomorrow

Predictions are now calling for less snow over Seattle tomorrow, probably only 2-5 inches. From Everett to Olympia, there will be less and less more and more snow as you head south.

Update: as some astute readers pointed out, CliffMassTLDR got the prediction of snow intensity backwards. Thanks for catching that.

Monday, January 16, 2012

I am exhausted thinking about all this weather action

There's gonna be some snow Tuesday, but the main event is Wednesday. The next few days have been hard to predict because two airstreams are battling it out up there.

The biggest snowstorm in years

Maybe. You know how those models are, always so fickle. But it looks like everything is going to be delayed by a day. In other words, there was obviously no snow event today; and Wednesday's slush might actually be lots more snow. Details tonight, after these models make up their beautiful minds.

More importantly, my lost dog was just spotted in Mountlake Terrace!

Saturday, January 14, 2012

Time for a nowcast!

Nowcast: lucky Everett, they got the Convergence Zone. It's snowing there now. Elsewhere, the snow level is 500ft. Snow showers in the mountains, of course.

Colder temperatures and more widespread snow tomorrow, up to a few inches.

More snow late Monday, and then wet snow early Wednesday, turning into rain.

Cliff Mass academic paper: TLDR

I published an academic paper about Nowcasting. "Nowcasting" is awesome because instead of requiring a prediction of what the weather will be like in the days ahead, all I need to do is describe the current weather on my blog. Oh, and it creates synergy.

Wednesday, January 11, 2012

SNOW, er, I mean "snow?"

This increasing threat of snow SHOULD NOT BE OVERHYPED! Repeat: do not OVERHYPE the increasingly threatening forecast models, which predict colder temperatures and lowland snow from Sunday through Wednesday.

Tuesday, January 10, 2012

I'm going to use the word "snow"...

We'll have several dry days, but past Friday, there could be...


We'll know by Thursday.