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Winter 2019-2020: Modified Modoki


40/70 Benchmark
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https://easternmassweather.blogspot.com/2019/11/winter-2019-2020-modified-modoki.html

City

Predicted Snowfall

Actual

Forecast Error

Boston, MA

45-55”

?

?

New York, NY

20-30"

?

?

Philadelphia, PA

17-27"

?

?

Baltimore, MD

15-25”

?

?

Washington, DC

15-25”

?

?

Albany, NY

65-75”

?

?

Hartford, CT

50-60”

?

?

Providence, RI

40-50”

?

?

Worcester, MA

70-80”

?

?

Tolland, CT

60-70"

?

?

Methuen, MA

65-75”

?

?

Hyannis, MA

20-30”

?

?

Burlington, VT

80-90"

?

?

Portland, ME

70-80”

?

?

Concord, NH

65-75”

?

?

 

 

 

Index Value

Predicted '19-'20 DM   Value Range

Actual  '19-'20 DM Value

Forecast Error

Pacific Decadal Oscillation (PDO)

0 to .30

?  

?   

Perennial North American Pattern (PNA)

.15 to .45

?   

?    

ENSO

Weak Modoki El Nino   (0.3 to 0.5C ONI) (NDJ)

 

0.5C NDJ ONI

.50 Modoki    

 

?

 (J-M) East Pacific Oscillation (EPO)

-.15 to -.45

?    

?    

Arctic Oscillation (AO)

0 to -.30

?   

?    

North Atlantic Oscillation (NAO)

-.15 to .15

?

 

?

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3 hours ago, SnoSki14 said:

Wow was that well thought out.

Good luck this season, hopefully it verifies a little more optimistic than you have particularly further south. 

Like I just said in mid atl forum, it was difficult for me to communicate the potential of the second half, while concomitantly conveying that it was lower confidence due to the reliance upon the onset of blocking.  I am more confident in the PNA period.

I feel at least some blocking materializes second half....but it will suck if it doesn't. Should be some NAO in Dec, too, but transient.

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9 minutes ago, Isotherm said:

@40/70 Benchmark, great, detailed work as per usual. You are colder and blockier than me overall, but we concur that late season has the highest probability of inducing such action centers.

Thanks, Tom. I have learned alot from your work, as always.

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Take it or leave it but -

1) When you evaluate your forecasts, you should use (observed-forecast)/(observed) as your metric. You somehow have last year's call for 80"+ as only a 60-something percent error, when Boston only had 27". The math should be (80-27)/(27), i.e. your forecast was around +200% (triple) observed. Observed is the anchor, not the forecast.

2) I suspect December will be a lot warmer than you have in the North/East. Nino 4 is around 1.0C warmer than your composite. Even years with a lot of blocking aren't that cold in December when Nino 4 is that warm. My composite in my forecast had Nino 4 too cold too, so I mentioned I expected the East and North to be 2-3F warmer than depicted by the raw analogs. 

3) It does amuse me that despite pretty different background states in some ways, you essentially forecast the same thing nationally two years in a row. Doesn't mean your wrong this time, just amuses me.

 NqzPGYa.png

4) A lot of your very cold analogs for the East had much higher solar than this year: 1958, 1969, 1989, 2014. I think 1958 and 1989 are literally around 255 sunspots/month and 200 sunspots/month for July-June. This July-June is probably...3? Maybe 4? If you take out those four years, the cold signal is gone in December for the East.

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1 hour ago, raindancewx said:

Take it or leave it but -

1) When you evaluate your forecasts, you should use (observed-forecast)/(observed) as your metric. You somehow have last year's call for 80"+ as only a 60-something percent error, when Boston only had 27". The math should be (80-27)/(27), i.e. your forecast was around +200% (triple) observed. Observed is the anchor, not the forecast.

2) I suspect December will be a lot warmer than you have in the North/East. Nino 4 is around 1.0C warmer than your composite. Even years with a lot of blocking aren't that cold in December when Nino 4 is that warm. My composite in my forecast had Nino 4 too cold too, so I mentioned I expected the East and North to be 2-3F warmer than depicted by the raw analogs. 

3) It does amuse me that despite pretty different background states in some ways, you essentially forecast the same thing nationally two years in a row. Doesn't mean your wrong this time, just amuses me.

 NqzPGYa.png

4) A lot of your very cold analogs for the East had much higher solar than this year: 1958, 1969, 1989, 2014. I think 1958 and 1989 are literally around 255 sunspots/month and 200 sunspots/month for July-June. This July-June is probably...3? Maybe 4? If you take out those four years, the cold signal is gone in December for the East.

Thanks, but I'll leave it. Forecast error for me is the percentage that verified seasonal snowfall totals deviated from my forecast range. Regardless, the forecast and verified totals are there to see. It was bad in sne. I focus most on snowfall, and its much less in the northeast than last season's forecast. Additionally, the forecast is not as cold as the composite maps...I specified that. Last season, I forecast an epic second half..this season, its onky salavagable with blocking. It wasn't that warm in the east last year.

Good luck-

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Your percentage listed for Boston is 80-27/80. Comparing the error to the theoretical total (80") doesn't make any sense. If I told you your kid was going to be 8 feet tall and the kid ended up 3 feet tall would you call that a 60% error? That's what you did. It's closer to a three fold error. I had 35" in my blend last year, and even that is a 30% error for Boston if you use real math.

You picked average snow this year, so mathematically you don't have to worry anyway, it's more or less impossible to be as wrong as last year for Boston, so in that sense at least I'm sure you have a much better forecast.

I don't really care what people forecast, but if you are going to grade yourself, you need to do (expected-actual)/(actual). You did (expected-actual)/(expected) which doesn't mean anything.

 

 

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34 minutes ago, raindancewx said:

Your percentage listed for Boston is 80-27/80. Comparing the error to the theoretical total (80") doesn't make any sense. If I told you your kid was going to be 8 feet tall and the kid ended up 3 feet tall would you call that a 60% error? That's what you did. It's closer to a three fold error. I had 35" in my blend last year, and even that is a 30% error for Boston if you use real math.

You picked average snow this year, so mathematically you don't have to worry anyway, it's more or less impossible to be as wrong as last year for Boston, so in that sense at least I'm sure you have a much better forecast.

I don't really care what people forecast, but if you are going to grade yourself, you need to do (expected-actual)/(actual). You did (expected-actual)/(expected) which doesn't mean anything.

 

 

Gotcha. I'm not a big math guy....social worker by trade. :lol:

I can do that in the future, but the forecast amounts vs actual are there for everyone to see.

I'm quite happy with my level of success overall, last year not withstanding.

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7 hours ago, 40/70 Benchmark said:

Gotcha. I'm not a big math guy....social worker by trade. :lol:

I can do that in the future, but the forecast amounts vs actual are there for everyone to see.

I'm quite happy with my level of success overall, last year not withstanding.

I think the most meaningful thing for this would actually be to grade yourself vs. climatology. This applies to everyone of course, not just you. The whole point of this exercise should be to get skill over climatology in the long hall. 

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8 hours ago, 40/70 Benchmark said:

Gotcha. I'm not a big math guy....social worker by trade. :lol:

I can do that in the future, but the forecast amounts vs actual are there for everyone to see.

I'm quite happy with my level of success overall, last year not withstanding.

BOS should not even be used. There are other sites nearby, (myself, Hingham, and I'm sure some nearby north shore areas you can use as a proxy with what fell relative to normal). 

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1 hour ago, CoastalWx said:

BOS should not even be used. There are other sites nearby, (myself, Hingham, and I'm sure some nearby north shore areas you can use as a proxy with what fell relative to normal). 

The kids must know by now not to bother daddy after the news reports the official BOS snowfall. :lol:

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Last year's BOS total was unusable. There's really no other way to spin it. We're not just talking about the old weenie "But Logan isn't representative of the city!!"....I'm talking about versus normal Logan airport measurements..... last year's snow measurements were sometimes late, measured after events ended, and apparently out at the water treatment plant on deer island. The fact that Hingham on the water had 43.3" while BOS had 27" is enough evidence on how bad last year's total was. It was the first year of using the new observer and observation location....

 

Show me which year doesn't "look like the others":

 

Year..............BOS.....Hingham

2014-2015....110.6....117.7

2015-2016....36.1......37.4

2016-2017....51.7......47.6

2017-2018....60.2......59.9

2018-2019....27.4......43.3

 

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Just now, CoastalWx said:

No kidding....lol. It's telling. And the funny thing about this, is that Hingham does it more the traditional once a day I believe, vs every 6 hrs like KBOS should do. 

I only listed the past few years....but its the same going back much further....that 27.4 vs 43.3 is by far the biggest discrepancy....and it's not getting fixed either. That awful 27.4 value is going to stay there unless NWS BOX wants to try and jump through 10 million hoops to change it.

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8 minutes ago, ORH_wxman said:

I only listed the past few years....but its the same going back much further....that 27.4 vs 43.3 is by far the biggest discrepancy....and it's not getting fixed either. That awful 27.4 value is going to stay there unless NWS BOX wants to try and jump through 10 million hoops to change it.

Yeah they usually aren't far off. Last year though, yeesh. And he is not far from the water either. For all intents and purpose, the climo in both places is fairly similar. I know you know this, but just speaking to the wider audience. There is no excuse for that difference in snow.

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2 hours ago, ORH_wxman said:

I only listed the past few years....but its the same going back much further....that 27.4 vs 43.3 is by far the biggest discrepancy....and it's not getting fixed either. That awful 27.4 value is going to stay there unless NWS BOX wants to try and jump through 10 million hoops to change it.

Not disagreeing, but isnt there a reliable site closer to Winthrop than Hingham?

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