May 2017 Observations and Model Discussion for the Pacific Northwest

[Phil]

Both Tim and Jesse would like the ECMWF monthlies.

 

Depicts an Aleutian ridge/PNW trough, but it's more of a northerly flow than a westerly one, so the end result is widespread cooler than average temperatures across the region, but below average precipitation as well. Almost looks like a winter wavetrain, very low WHEM wavebumber.

[Phil]

Well what do you know, the 12z EPS actually followed the progression of the bias-corrected 12z GEFS for d11-15, though it's a few days slower with the progression. They both consolidate the EHEM forcing as well, which wasn't the case before. Has the circus show finally ended?

[Front Ranger]

1995 had a nice stretch there of 22 consecutive days without measurable rain at PDX from May 13 to June 3.

 

A wet July and the wettest winter in PDX history soon followed.

 

Yeah, but mainly due to a couple days that had heavy rain. That month was still quite summery. Tim-approved.

[Front Ranger]

I'm not going to bother critiquing you or your weaknesses as a forecaster, however, maybe you should put your money where your mouth is and make a seasonal forecast of your own. Then we can compare when the summer is over.

 

I've participated in plenty of seasonal forecasts/contests. If you want to make a forecast thread, contest or whatever for this summer I'll be happy to play.

[Guest happ]

...NORTHWEST WASHINGTON...
    Seattle
    PTCLDY   PTCLDY   SUNNY    SUNNY    SUNNY    SUNNY    SUNNY   
      /63         49/69        52/76         55/81       57/82        58/81       57/80   
      

Very La La Land   overdue
 

[Phil]

I've participated in plenty of seasonal forecasts/contests. If you want to make a forecast thread, contest or whatever for this summer I'll be happy to play.

Just lay out your anticipated month-to-month progression and final result. That would tell me more than spitting out numbers than could be achieved via multiple different patterns.

[Jesse]

It's working for me. What browser are you using?

Just the one on my iPhone.

[Front Ranger]

Just lay out your anticipated month-to-month progression and final result. That would tell me more than spitting out numbers than could be achieved via multiple different patterns.

 

Sure, I'll play by whatever rules you want. Just as we did last summer.    

 

Where's yours?

[Front Ranger]

Just the one on my iPhone.

 

I have a droid, but have been getting a weird error on that site recently. "No Certificates Found". But if I hit cancel a few times, it loads.

[Phil]

Analogs compared to reality so far. I'd call this a win, could even match better when all is said and done.

 

Analogs for May:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/3AE86314-906B-4DA4-9891-3AF563A6FE91_zpsz33l2ymt.png

 

Versus May 2017 so far:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0133D660-2832-4311-9C80-7CBDABBC1222_zps3wgxmabm.png

[Phil]

Fast forwarding to June. I could see the actual result shifted eastward a bit compared to the analog mean.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/ADA890BA-00FF-4C59-81CA-B6AEE565962F_zps7wbjbz1y.png

[BLI snowman]

Yeah, but mainly due to a couple days that had heavy rain. That month was still quite summery. Tim-approved.

 

Very few Julys in Portland and Seattle have more than 5 days with rain. 

[Front Ranger]

Very few Julys in Portland and Seattle have more than 5 days with rain. 

 

This is true. But 1983 and 1993 both did. 

 

1993 had 13 with measurable precip at SEA.

[Front Ranger]

Fast forwarding to June. I could see the actual result shifted eastward a bit compared to the analog mean.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/ADA890BA-00FF-4C59-81CA-B6AEE565962F_zps7wbjbz1y.png

 

Maybe best to put this in the summer predictions thread? 

[Phil]

Sure, I'll play by whatever rules you want. Just as we did last summer.

 

Where's yours?

Let's get real with it. Detailed format.

 

My thoughts are based on historical progressions of the tropical NPAC thermo-convective gradient under descending QBO easterlies and dominant EHEM/Indo forcing:

 

June: Cool month overall for PNW. Ridging builds offshore early in the month, setting up downstream trough in western US including PNW. Second half of June is a more classic Niña pattern with ridges in the NPAC and SE US, trough axis centered a bit west of the continental divide.

 

July: Normal to slightly warm month in the PNW with a possible warm stretch early or mid month. Poleward shifted NPAC ridge and a -NAO will drive a more meandering flow over NW North America, could be more of a GOA-centered ridge that licks AK/EPO area and forces a few ULLs offshore for a few bouts of westerly/southwesterly flow. Late month flips +EPO.

 

August: Cool month in coastal PNW, more GOA trough, NPAC ridge shifts westward, ridging develops over intermountain west. Could be a stronger UV200 jet compared to normal. Should be a stronger -NAO, too.

 

So, what are your thoughts?

[Front Ranger]

Let's get real with it. Detailed format.

 

My thoughts are based on historical progressions of the tropical NPAC thermo-convective gradient under descending QBO easterlies and dominant EHEM/Indo forcing:

 

June: Cool month overall for PNW. Ridging builds offshore early in the month, setting up downstream trough in western US including PNW. Second half of June is a more classic Niña pattern with ridges in the NPAC and SE US, trough axis centered a bit west of the continental divide.

 

July: Normal to slightly warm month in the PNW with a possible warm stretch early or mid month. Poleward shifted NPAC ridge and a -NAO will drive a more meandering flow over NW North America, could be more of a GOA-centered ridge that licks AK/EPO area and forces a few ULLs offshore for a few bouts of westerly/southwesterly flow. Late month flips +EPO.

 

August: Cool month in coastal PNW, more GOA trough, NPAC ridge shifts westward, ridging develops over intermountain west. Could be a stronger UV200 jet compared to normal. Should be a stronger -NAO, too.

 

So, what are your thoughts?

 

Cool, I'll post mine in the summer thoughts thread tonight.

[TT-SEA]

This is true. But 1983 and 1993 both did. 

 

1993 had 13 with measurable precip at SEA.

 

Huge differences in the tangible weather between July 1993 and July 1995.

 

A wet summer month does not mean much... August of 2015 was very wet here and was still a very summery month.   It depends of course on the nature and persistence of the rain.    July of 1993 was about as bad as it gets around here while July of 1995 was a great summer month overall even though it was wetter in some places.  

[TT-SEA]

Fast forwarding to June. I could see the actual result shifted eastward a bit compared to the analog mean.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/ADA890BA-00FF-4C59-81CA-B6AEE565962F_zps7wbjbz1y.png

 

A slight eastward shift would be awesome.  

[TT-SEA]

Analogs compared to reality so far. I'd call this a win, could even match better when all is said and done.

 

Analogs for May:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/3AE86314-906B-4DA4-9891-3AF563A6FE91_zpsz33l2ymt.png

 

Versus May 2017 so far:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0133D660-2832-4311-9C80-7CBDABBC1222_zps3wgxmabm.png

 

 

That is a great match... easily call that a win.

 

In the end... I think the PNW will be warmer than the current map which is more in line with the analogs as well.  

[TT-SEA]

Just the one on my iPhone.

 

Works for me on my computer... although it did not load when I first checked after you reported the problem.   There have been intermittent issues so maybe you are just hitting it at the wrong time.

[TT-SEA]

The 12Z ECMWF control run and the EPS mean both bring in some troughiness after about day 13 (around June 6th).

 

Both were also more ridgy warm for all of next week compared to their 00Z runs... similar to the operational ECMWF.

[Jesse]

Works for me on my computer... although it did not load when I first checked after you reported the problem. There have been intermittent issues so maybe you are just hitting it at the wrong time.

Working now!

[Timmy Supercell]

Gusty today in my area. KLMT read a gust of 30 recently. Probably 35-40 up the hill.

[Jesse]

Really nice day.

[TT-SEA]

00Z GFS shows a ULL breaking off later next week from the massive Bering Sea low with some rain for us before turning very warm again as we get into the first weekend in June and beyond.

 

00Z GEM just stays warm and is getting even warmer at day 10.   

[Jesse]

GFS ensembles definitely starting to look better in the long range.

[IbrChris]

Tonight's ensembles throwing out some fairly impressive numbers for PDX suggesting ~3 days at or above 90. GFS ensembles the hottest with potential for mid 90s Sun-Mon. Mid-late next week looks more seasonable with low-mid 70s, more in the way of AM clouds. Potential for some Cascade thunderstorms at least toward central Oregon Mon-Tue though moisture looks pretty marginal. Overall message is hot (mean +15) fading to weakly above normal (mean +2) and continued below avg precip as we enter the first week of June.

Looking at peak 850 mb temps there's a range generally from 19c to 21c...GFS and GEFS on the lower end and Euro/EPS on the higher end. 20c H8 should be good enough for highs around 33-34c at the surface in late May assuming fairly flat to lightly offshore gradients...with 35c in the realm of possibility.

[Phil]

Quite the SSTA difference between now & last year at this time:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/736C2B36-E95E-4674-A4F7-111A3D27C651_zpsgs0ifao2.pnghttp://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/D3CF5ADA-C66B-4D44-A12F-080015CFD18C_zpsazc3ojih.png

[Timmy]

GFS ensembles definitely starting to look better in the long range.

I'm trying to remember if your "better" during spring and summer is "warm" or "cold". I'm pretty sure I am not going to like the answer

[TT-SEA]

I'm trying to remember if your "better" during spring and summer is "warm" or "cold". I'm pretty sure I am not going to like the answer

 

You won't.

 

"Better" is always cold and preferably wet for him.    Most of us switch sides depending on the season.  

[Jesse]

Tonight's ensembles throwing out some fairly impressive numbers for PDX suggesting ~3 days at or above 90. GFS ensembles the hottest with potential for mid 90s Sun-Mon. Mid-late next week looks more seasonable with low-mid 70s, more in the way of AM clouds. Potential for some Cascade thunderstorms at least toward central Oregon Mon-Tue though moisture looks pretty marginal. Overall message is hot (mean +15) fading to weakly above normal (mean +2) and continued below avg precip as we enter the first week of June.

 

Looking at peak 850 mb temps there's a range generally from 19c to 21c...GFS and GEFS on the lower end and Euro/EPS on the higher end. 20c H8 should be good enough for highs around 33-34c at the surface in late May assuming fairly flat to lightly offshore gradients...with 35c in the realm of possibility.

Three days 90+ over the long weekend seems pretty bullish. Especially considering a relatively small clout of ensemble members are advertising such a possibility, at least in the last few runs. But who knows, I guess.

[Jesse]

You won't.

 

"Better" is always cold and preferably wet for him. Most of us switch sides depending on the season.

It really annoys you doesn't it? I can't help my opinion. Better yet my opinion has no affect on the weather. And the preferably wet part is inaccurate.

[TT-SEA]

It really annoys you doesn't it? I can't help my opinion. And the preferably wet part is inaccurate.

 

Honestly does not bother me at all... you can't help what you like.

 

Wet is usually cold in the warm season so I think you prefer that... and then dry/cold in the cold season.  

[Jesse]

Honestly does not bother me at all... you can't help what you like.

 

Wet is usually cold in the warm season so I think you prefer that... and then dry/cold in the cold season.

Sounds great.

[Phil]

The 12z GFS just shifted equatorward w/ the descending branches of all major NH Hadley Cells by 72hrs except the East Asian one.

 

Suspicious.

[Phil]

Interesting stats from Phillip Klotzbach on Twitter. Through 5/25 this year, we have yet to observe a hurricane in the NH. Since 1950, the only other years to feature zero hurricanes through May 25th are 1973, 1977, 1984, 1993, 1995, and 2013, and all of these years (except 1984 and 2013) featured significant periods of -NAO during the month of May.

 

So maybe this says something as to the legitimacy of analogs featuring -NAOs in May, and the forcing homogeneity involved in such years.

[TT-SEA]

The 12z GFS just shifted equatorward w/ the descending branches of all major NH Hadley Cells by 72hrs except the East Asian one.

 

Suspicious.

 

Continues the idea of a trough extending eastward over the PNW later next week... and the 12Z GEM agrees.

 

That actually makes sense... it does not stay warm and dry at this time year here.

[Phil]

Continues the idea of a trough extended eastward over the PNW later next week... and the 12Z GEM agrees.

 

That actually makes sense... it does not stay warm and dry at this time year here.

Residual +AAM effects lagging the tropical forcing? If the jet extension is real, I don't think it lasts long before a ridge develops in the GOA. Tropics scream GOA ridge in early June followed by a shift further west (towards the Aleutians) during mid/late June.

[seattleweatherguy]

So if thar info is correct, we wont have a hot summer like the past few years? We are due for at least a avg summer or below in terns of temps

[TT-SEA]

So if thar info is correct, we wont have a hot summer like the past few years? We are due for at least a avg summer or below in terns of temps

 

Last summer was not hot at all.   Just slightly above average locally and cooler than normal for the region.