April Weather in the Pacific Northwest

[TT-SEA]

The hot, ridgy summers of recent years probably nullified any water-table increases from the rainy winters. Those hot, sunny days really accelerate the evaporation rate. It’s more complicated than adding/subtracting a few numbers.

 

Your climate seems to have a long term, seasonal yin/yang aspect to it. It’s pretty balanced. For example, in the paleoclimate record, warm periods like the MWP featured lots of winter rainfall, but very warm/dry summers. Cold climate periods, on the other hand, featured the opposite tendency, with much colder/drier winters, but wetter summers. So the effects on the water table and ecosystems were somewhat softened.

2015-16 was the wettest winter on record and then we had a relatively normal to slightly cool summer in 2016 across the region.

 

Then 2016-17 became the wettest winter on record and last summer was only really hot in August and the entire year was WAY above normal for precipitation.

[Phil]

(OT) A statistical shame we had a midnight here, or today would have been record breaking for daytime highs.

 

The temperature at 12pm was 39.6*F despite peeks of sunshine, and has been hovering just above 40*F all afternoon with intermittent snow flurries. If we clear tonight, we should drop into the low/mid 20s.

[Deweydog]

(OT) A statistical shame we had a midnight here, or today would have been record breaking for daytime highs.

 

The temperature at 12pm was 39.6*F despite peeks of sunshine, and has been hovering just above 40*F all afternoon with intermittent snow flurries. If we clear tonight, we should drop into the low/mid 20s.

We had a midnight here too. First one in a while.

[Timmy]

Did this wind thing already happen or what?

[MossMan]

Not windy.

[seattleweatherguy]

Forecast busted?

[Phil]

2015-16 was the wettest winter on record and then we had a relatively normal to slightly cool summer in 2016 across the region.

 

Then 2016-17 became the wettest winter on record and last summer was only really hot in August and the entire year was WAY above normal for precipitation.

Don’t even try...A/M/J 2016 was much warmer and drier than normal with two heatwaves. Also, the summers of 2013, 2014, 2015, and 2017 were all record breakers for heat/ridging. It was easily the ridgiest period since at least 1850 on ESRL reanalysis. Huge anomaly.

 

If you’re well-versed in hydrodynamics, then you know the increasing efficiency through which evaporation occurs under persistent insolation/low cloud cover, as the water table is drawn down and more work goes into surface heating rather than evaporation/latent heat absorption.

 

Remember all that wildfire smoke last summer? What causes fire to spread? Hint: It’s not excessive moisture and a high water table.

[MossMan]

Don’t even try...A/M/J 2016 was much warmer and drier than normal with two heatwaves. Also, the summers of 2013, 2014, 2015, and 2017 were all record breakers for heat/ridging. It was easily the ridgiest period since at least 1850 on ESRL reanalysis. Huge anomaly.

 

If you’re well-versed in hydrodynamics, then you know the increasing efficiency through which evaporation occurs under persistent insolation/low cloud cover, as the water table is drawn down and more work goes into surface heating rather than evaporation/latent heat absorption.

 

Remember all that wildfire smoke last summer? What causes fire to spread? Hint: It’s not excessive moisture and a high water table.

Most of the fires started last year were courtesy of dumb a** morons.

[Phil]

In fact, from 2013-17, the PNW was under the highest 500mb height anomaly of anywhere in the world.

 

I’m not even sure why this is being debated..2013-17 was the farthest thing from “normal” you could possibly see.

[FroYoBro]

It was a bit windy around 11:30. Nothing since.

[TT-SEA]

Don’t even try...A/M/J 2016 was much warmer and drier than normal with two heatwaves. Also, the summers of 2013, 2014, 2015, and 2017 were all record breakers for heat/ridging. It was easily the ridgiest period since at least 1850 on ESRL reanalysis. Huge anomaly.

 

If you’re well-versed in hydrodynamics, then you know the increasing efficiency through which evaporation occurs under persistent insolation/low cloud cover, as the water table is drawn down and more work goes into surface heating rather than evaporation/latent heat absorption.

 

Remember all that wildfire smoke last summer? What causes fire to spread? Hint: It’s not excessive moisture and a high water table.

 

 

 

There are wildfires every year.   Last year it was enhanced by an unusual dry period... followed by late season heat.   

 

Don't even try?   You spent most of summer of 2016 telling me how it was cool across the PNW and I kept pointing to the area slightly above normal area near the Sound.  

 

And then we followed that up with the wettest winter ever once again and extremely healthy snow pack.   

[Deweydog]

I can't believe there aren't damaging winds verifying with that low being so close to us!

[Phil]

Most of the fires started last year were courtesy of dumb a** morons.

But there are dumba** morons every year, probably a similar number every year. The super dry vegetation and low ambient moisture is what allowed the fires to spread.

[TT-SEA]

In fact, from 2013-17, the PNW was under the highest 500mb height anomaly of anywhere in the world.

 

I’m not even sure why this is being debated..2013-17 was the farthest thing from “normal” you could possibly see.

 

Phil is changing the argument again and going off on a tangent.    

 

The last 4 years have been warmer than normal and very wet.     Who said it was normal?    Where is that being debated?

[SilverFallsAndrew]

Phil is 100% spot on. When I think of the 2013-2017 period the persistent West Coast ridge is what stands out.

[Phil]

Maybe the colder Pacific SSTs at this time of year are allowing for a slightly more isothermal lower boundary layer to develop over the area? I haven’t been following this storm so I don’t know the exact mesoscale dynamics in play.

[seattleweatherguy]

Maybe the colder Pacific SSTs at this time of year are allowing for a slightly more isothermal lower boundary layer to develop over the area? I haven’t been following this storm so I don’t know the exact mesoscale dynamics in play.

Well there is no storm, but good points on the ridge that caused all those hot summers

[Phil]

Phil is changing the argument again and going off on a tangent.

 

The last 4 years have been warmer than normal and very wet. Who said it was normal? Where is that being debated?

Let me get this straight. Are you actually claiming that adding up yearly rainfall totals and finding the departure will tell you the *actual* moisture deficit/surplus?

 

Oh lordy.

[Deweydog]

Maybe the colder Pacific SSTs at this time of year are allowing for a slightly more isothermal lower boundary layer to develop over the area? I haven’t been following this storm so I don’t know the exact mesoscale dynamics in play.

This storm's trajectory is not favorable for particularly strong winds away from the coast. The convective mixing thanks to the late inversion season sun angles are the x factor in seeing more formidable gusts than you'd expect from a low on this trajectory.

[TT-SEA]

Let me get this straight. Are you actually claiming that adding up yearly rainfall totals and finding the departure will tell you the *actual* moisture deficit/surplus?

 

Oh lordy.

 

Ohhhh lordy lordy lordy!   

 

Conversely... the ground is throughly saturated here for probably 8 months of every year with rain on the majority of days and very little evaporation or even sunshine. 

 

We desperately need to have rain on most days for 8 months so we can survive our brutally hot and desert-like summers.   

 

We have been dumping water into the rivers and ocean here since November... ground can't take more.    This is normal. 

 

The reality is we have about 8 weeks a year to survive where evaporation is high.   The other 44 weeks are in preparation for those 8 weeks!    

[Phil]

Don't even try? You spent most of summer of 2016 telling me how it was cool across the PNW and I kept pointing to the area slightly above normal area near the Sound.

For the record, I predicted a cool J/A/S, not a cool J/J/A.

 

That actually verified over ~ 90% of the PNW. That stupid warm bubble around Puget Sound was a minor s**t stain.

 

And then we followed that up with the wettest winter ever once again and extremely healthy snow pack.

Followed by yet another top-5 all time hot/ridgy summer, after three consecutive blast furnaces in 2013-15. See the picture that’s emerging?

[seattleweatherguy]

Will that warm bubble go away?

[SilverFallsAndrew]

Last summer was like a nightmare I had seen before!

[Phil]

Ohhhh lordy lordy lordy!

 

Conversely... the ground is throughly saturated here for probably 8 months of every year with rain on the majority of days and very little evaporation or even sunshine.

 

We desperately need to have rain on most days for 8 months so we can survive our brutally hot and desert-like summers.

 

We have been dumping water into the rivers and ocean here since November... ground can't take more. This is normal.

 

The reality is we have about 8 weeks a year to survive where evaporation is high. The other 44 weeks are in preparation for those 8 weeks!

Which is what your regional ecosystem requires. Any deviation from that can change the overall moisture balance.

 

For instance, warm winters with heavy rains will dump less snow in the foothills and have a higher runoff percentage (and a lower absorption percentage). When followed by extended hot/dry summers, more of the ambient moisture is evaporated, and you can easily finish with a large moisture (deficit relative to average) as a result. All that despite a positive rainfall anomaly. Who woulda thunk it?

[SilverFallsAndrew]

Many people don't understand the relationship between soil moisture and summer temperatures, and also the role vegetation plays in ambient temperature. 

 

I learned this during Oklahoma summers. Though early summer is hot in Tulsa, there is usually not extreme heat until the soil dries out and the vegetation browns. The reason why 100+ temps are fairly rare before mid-July. 

[TT-SEA]

Which is what your regional ecosystem requires. Any deviation from that will change the equilibrium point.

 

For instance, warm winters with heavy rains dump less snow in the foothills and increase runoff/reduce absorption. When followed by extended hot/dry summers, more of the ambient moisture is evaporated, and you end up with a moisture deficit relative to average.

 

All that despite a positive rainfall anomaly. Who woulda thunk it?

Statistically speaking... we are due for a couple drier than normal years. Or our rainfall average just jumped way up.

 

And the ground is thoroughly saturated right now. And the mountains in BC and WA are doing just fine.

 

Not sure what your point is... but it's been statistically wet since 2014 and water is dumping out into the ocean at this point. It's roaring down our ridge right now (heading for the Pacific).

 

Hard to say we are in a drought.

 

But I am sure it's very dire despite all of this.

[WeatherArchive]

So how do you like your big "windstorm"?  Some huffs but not any puffs.

[Phil]

Many people don't understand the relationship between soil moisture and summer temperatures, and also the role vegetation plays in ambient temperature.

 

I learned this during Oklahoma summers. Though early summer is hot in Tulsa, there is usually not extreme heat until the soil dries out and the vegetation browns. The reason why 100+ temps are fairly rare before mid-July.

Exactly. It’s also why Phoenix sees 115*F-120*F heat relatively often, while places like Birmingham/Atlanta seldom reach 100*F. Lots of latent heat absorption in the evaporative process, and a significant portion of the insolation will be “invested” in said evaporative work.

 

As the antecedent moisture content is drawn down, a larger quantity of insolation is available for heating.

[WeatherArchive]

So how do you like your big "windstorm"?  Some huffs but not any puffs.

 

Off and on torrential downpours here all day but nary a gust of wind to speak of. Not even a breeze.

We had some huffs but not really any puffs!

[Phil]

Statistically speaking... we are due for a couple drier than normal years. Or our rainfall average just jumped way up.

 

And the ground is thoroughly saturated right now. And the mountains in BC and WA are doing just fine.

 

Not sure what your point is... but it's been statistically wet since 2014 and water is dumping out into the ocean at this point. It's roaring down our ridge right now (heading for the Pacific).

 

Hard to say we are in a drought.

 

But I am sure it's very dire despite all of this.

For the record, I never said it was “dire”. I don’t live there but I’m guessing that’s an exaggeration.

 

That said, I’d would bet a large sum of money that you’ve been running an overall moisture deficit (relative to your regional averages) since 2013. Probably a moderate one, nothing “dire”.

 

And I would also argue that you’re due for a string of cooler, wetter summers, and drier, more continental winters.

[TT-SEA]

Many people don't understand the relationship between soil moisture and summer temperatures, and also the role vegetation plays in ambient temperature. 

 

I learned this during Oklahoma summers. Though early summer is hot in Tulsa, there is usually not extreme heat until the soil dries out and the vegetation browns. The reason why 100+ temps are fairly rare before mid-July. 

 

There has been some brutal evaporation around here since last October.   

 

 

http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/Figures/daily/curr.w.full.daily.gif

[Jesse]

Has this discussion really been continuing all day?

 

Anyway, we are in Bend now. Doing an overnighter here. Apparently it was very windy earlier today (the official station here reported gusts over 50) but it appears to be dying down now. Partly sunny, breezy and 52 atm.

[SilverFallsAndrew]

Check out this monster!

 

[Dave]

It has been really windy down here since about mid morning.  NWS says our peak gust was 50mph. There's a bit of a lull right now.

[Phil]

There has been some brutal evaporation around here since last October.

 

 

http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/Figures/daily/curr.w.full.daily.gif

Should I post a running sum of soil moisture *anomalies* in response to this?

[TT-SEA]

For the record, I never said it was “dire”. I don’t live there but I’m guessing that’s an exaggeration.

 

That said, I’d would bet a large sum of money that you’ve been running an overall moisture deficit (relative to your regional averages) since 2013. Probably a moderate one, nothing “dire”.

 

And I would also argue that you’re due for a string of cooler, wetter summers, and drier, more continental winters.

 

Just looking at the last 2 years... precipitation has been way above normal for most of the area and only 1 degree above normal.     I don't believe that WA state is trouble in terms of water right now.    

 

Seattle was approaching 20 inches above normal for rainfall in 2016 and 2017 combined.      

 

 

 

 

 

[TT-SEA]

Should I post a running sum of soil moisture *anomalies* in response to this?

 

Link me.   

 

I would love to know the deficit in Western Washington since 2016.   

 

Either way... the ground is 100% saturated now.   Can't get any more full.   You can't fill the gas tank beyond its capacity.    Mountain snow is the back up tank and that is doing just fine in BC and WA.      

[Phil]

The current soil moisture anomaly (year to date) is pretty close to normal, and since January 31st, the anomaly has actually decreased a bit.

 

 

[Phil]

I was right. The soil moisture surplus following the “wettest winter on record” in 2016/17 was completely erased by the scorching summer that followed.

 

June-October 2017, watch the running soil moisture anomaly:

 

 

 

 

 

[TT-SEA]

Meaningless Phil... normal is fully saturated here in the winter and early spring.     You can't really be above normal for soil moisture in western WA... its like having more gas in the tank than its capacity.

 

Show me the soil moisture accumulated deficit for 2016 and 2017 for western WA.