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Chief Joseph
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PostSat Mar 02, 2019 10:03 am 
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I might believe in Global Warming as it relates to the Biblical Prediction that the Human Race will be destroyed by fire, just as it was the first time by the Great Flood. But, to believe that will happen takes a Leap of Faith, which many people lack. Only time will tell.

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Go placidly amid the noise and waste, and remember what comfort there may be in owning a piece thereof.
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RichP
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PostSun Mar 03, 2019 9:22 am 
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Tonight is predicted be the coldest night of the year in these parts. -3 or -4f but windchill will be far below that.

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Without obsession, life is nothing. John Waters
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treeswarper
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PostSun Mar 03, 2019 9:37 am 
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RichP wrote:
Tonight is predicted be the coldest night of the year in these parts. 3 or 4f but windchill will be far below zero.

My neighborhood does not reach the lows predicted.  Temps are usually 8 to 10 degrees warmer.  The weather service has their station in a more exposed location.   Last week, when they predicted a high of 32, it it 44.  I am thankful for this.

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What's especially fun about sock puppets is that you can make each one unique and individual, so that they each have special characters. And they don't have to be human––animals and aliens are great possibilities
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Chief Joseph
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PostSun Mar 03, 2019 10:45 am 
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Got down to 0 here last night, 8 below less than a mile away and a few hundred feet lower. 20  degrees now, heat wave!

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Go placidly amid the noise and waste, and remember what comfort there may be in owning a piece thereof.
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RichP
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PostMon Mar 04, 2019 9:20 am 
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Coldest March temp records broken or tied in several locations.

https://komonews.com/weather/scotts-weather-blog/frozen-cougars-pullman-shatters-record-for-coldest-march-temperature-on-record

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Without obsession, life is nothing. John Waters
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gb
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PostThu Mar 07, 2019 5:15 pm 
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rossb wrote:
I think this is a great example of how unreliable long term forecasts are, and how important it is to not place too much faith in them. Meteorologists know this, which is why no professional would make the following statement:

gb wrote:
This amazing stretch of cool to cold weather finally looks like it will end around February 26th and then all the more so by March 2nd or so with temperatures going well above normal for at least several days. The cold weather will be replaced by warmer air and the promise of one or more of my other all-time favorite things, another blooming Pineapple Express.

What is striking is not the forecast itself, or even how wrong it was, but the confidence with which it was stated. Not "there is a good chance" of warm weather or wet weather, but that it was going to happen. We were gong to have temperatures well above normal by now, and the promise of a Pineapple Express. This didn't happen. Or rather, I feel confident enough to boldly claim that it won't happen. The period you mentioned ends tomorrow (so technically there is still a chance) but I know enough about the short term forecast to proclaim -- with similar confidence -- that your forecast will be a bust.

Not just by a little bit, either. It is striking how wrong your forecast was. You predicted much warmer and wetter than average temperatures, but it has been much colder and drier of late. Your prediction could not have been more wrong. A random forecast would have been more accurate. You called for one extreme and we had the other. Obviously some of this was bad luck, but it is still striking how bad the prediction was.

What bothers me about such predictions is that they imply that weather forecasting in general is just as bad. That simply isn't the case. Short term forecasts are remarkably accurate. Short term forecasts combined with a reading of the forecast discussions are extremely accurate. If you read a forecast and the NWS forecaster says all the models agree (i. e. there is no issues with the forecast) then you can pretty much bank on it. That is why I feel confident that tomorrow's weather will not be warmer or wetter than that typically found on March 2.

Let me get specific here. The forecast for Seattle is for a high of 43 tomorrow, with no rain. Average high for Seattle on March 1st is 53 degrees. Above average is a judgement call, but I will add only a couple degrees, and call it 55. Therefore, I will make the bold claim that we will not have temperatures above 55 tomorrow. I would not have made that prediction a month ago, but based on the forecasting, I'm ready to make that prediction. I would even give you ten to one odds that we won't crack 55 tomorrow. I would bet $100 to your $10 that we won't hit 55 degrees. That is how confident I am in the short term forecast, and this is typical.

Of course I could be wrong. But if I made similar bets a dozen times, I would probably end up with 20 bucks in my pocket. Forecasts of this sort are that accurate. Not 99 times out of a 100, but somewhere around 95 out of a 100.

But that simply isn't the case with long term forecasts. Do that with long term forecasts a dozen times and you are likely to be in whole hundreds of dollars.

I'm not trying to pick on you for your prediction. If you want to put a lot of faith in long term forecasts, or where you think the stock market will be in a year, be my guest. But it bothers me when it gives the impression that forecasting in general is inaccurate, when it is only long term forecasting that is.

What you are suggesting is that I made the forecast up, rather than watching forecast models. Each successive model run after whatever date it was pushed the Pineapple Express further south from SW Washington/Oregon border to eventually end up for that period in Northern California where it was a major Pineapple Express that also had a significant effect to Bend Oregon as well with Bachelor recording 48" of new snow in 48 hours.

But that is not to say the Cleveland forecast 6-10 days out was not correct. Cleveland yesterday was 16-21F below normal and is similarly below normal today as the extended models and guidance verified. It will still be below normal tomorrow and then will moderate for 36 hours before falling significantly below normal again on Saturday. Thus the 6-10 day period will have been much bellow normal, and the Indiana/Ohio area is anomalous as the models correctly forecast a warm front followed by a cold front. And it was not me that suggested Cleveland; it was foist. I said from the Dakotas through the Great Lakes.
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gb
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PostThu Mar 07, 2019 5:45 pm 
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At this point now, and with cold air thinning in BC and Eastern Washington as is typical as we draw nearer spring, the "end" will show up somewhat and briefly for a day or two around the 12th, but return with a vengeance beginning about March 17th. For several days following a currently forecast Pineapple Express, a warm long wave Pacific Ridge will move over us and put an end to this amazing bout of cold weather. Where the Pineapple Express strikes may change, but the dome of high pressure with freezing levels by the 20th rising to above 8000' to perhaps 11,000' looks pretty likely. It will affect the entire West and Intermountain Basin. The ridge at present appears transitory and around the 23rd we may go back to a "normal" late March Pattern. The CPC suggests as much, particularly for California.

Not surprisingly, this is based on weather models that have been pretty consistent for several days and, of course, the CPC talks about this in general detail in their Monthly Outlook Discussion which was originally released February 21st and revised February 28th.

But it is not me that is forecasting this swing and finally major change, it is the forecast models. Ironically, some who don't believe in weather forecast models likely believe in Angels and such.

Why do I follow the forecast models? For short and long term trip planning. Yesterday we scheduled Mountaineer trips based on these expectations and with data on snowpack. For me, I will ski in California this spring, but will watch consolidation based on temperatures and the significance of storms as we go into spring. I don't want too high of freezing levels, nor cool and windy, and certainly not significant snowstorms in the high country.

I have successfully used long term forecast models for extended trip planning since the early 1980's when model charts were posted in a room on the 6th floor of the Atmospheric Sciences building on campus. I had a number of skiing and climbing friends who were working on PHD's in meteorology and glaciology and helped me learn the mostly rather simple interpretation of these outputs.

There are times and sets of conditions where the models can be very accurate for ten day or longer periods and times when they cannot. But that is obvious if one looks successively for several forecasting periods for a certain time period and location and supplement that readily available resource with current and extended Weather Service Office Forecast Discussions.

For instance, to have reliable weather in late May/early June at City of Rocks, look for zonal flow with 500mb heights of around 570 DCM. I won't be too hot nor too cold by and large, and the weather will generally be good.

Or one can stumble blindly and rely on Angels and such to have a successful trip....
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rossb
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PostFri Mar 08, 2019 12:43 pm 
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gb wrote:
rossb wrote:
I think this is a great example of how unreliable long term forecasts are, and how important it is to not place too much faith in them.

What you are suggesting is that I made the forecast up, rather than watching forecast models.

Nonsense. Nowhere did I say "you made things up". I only said that you place way too much faith in long term forecasts. You don't seem to get it. Even meteorologists don't place that much faith in long term forecasts. Again, they are very confident in the short term forecasts. When they aren't confident, it shows up in the discussion. This means that lots of people (myself included) have great confidence in the short term forecasts when combined with the discussions. For good reason! They are almost always right. I would say 95% of the time, if not higher (thus my decision to give you ten to one odds). Are you really saying you would give ten to one odds on the long term forecast being correct? Seriously?

The lack of confidence explains why it is difficult to even find long term forecasts, or why meteorologists consider "long term" to be about a week, not a month. Even a week out the folks who make forecasts are a bit wary. It is not their focus. Why waste a lot of energy, when you know the models simply aren't that accurate?

Here, let me give you an example. Here is the main Northwest National Weather Service website (hosted by the UW). You can see gobs of information here. You can also see a ton of forecasts; most (if not all) are for a week or less.  Here is the zone forecast for the Northwest. Notice that it doesn't go out farther than a week. Sometimes it doesn't even go that far. This is the only period in which they have confidence. Now read the discussion. In the discussion they talk about the various models, and how they are basing their forecast on them. Then they talk about "Long Term", which they consider to be three days from now. They break up the forecast into two different periods, based on confidence. But anything over a week and they don't even bother. Sure, there are models in which they can base a forecast, but they don't bother, because they know they are ridiculously unreliable.

Yet you seem to think that some long term model (or models) is extremely accurate, with little to no evidence to support it. Your only anecdotal example -- the basis of this post -- was completely wrong.
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gb
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PostSat Mar 09, 2019 8:07 am 
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rossb wrote:
gb wrote:
rossb wrote:
I think this is a great example of how unreliable long term forecasts are, and how important it is to not place too much faith in them.

What you are suggesting is that I made the forecast up, rather than watching forecast models.

Nonsense. Nowhere did I say "you made things up". I only said that you place way too much faith in long term forecasts. You don't seem to get it. Even meteorologists don't place that much faith in long term forecasts. Again, they are very confident in the short term forecasts. When they aren't confident, it shows up in the discussion. This means that lots of people (myself included) have great confidence in the short term forecasts when combined with the discussions. For good reason! They are almost always right. I would say 95% of the time, if not higher (thus my decision to give you ten to one odds). Are you really saying you would give ten to one odds on the long term forecast being correct? Seriously?

The lack of confidence explains why it is difficult to even find long term forecasts, or why meteorologists consider "long term" to be about a week, not a month. Even a week out the folks who make forecasts are a bit wary. It is not their focus. Why waste a lot of energy, when you know the models simply aren't that accurate?

Here, let me give you an example. Here is the main Northwest National Weather Service website (hosted by the UW). You can see gobs of information here. You can also see a ton of forecasts; most (if not all) are for a week or less.  Here is the zone forecast for the Northwest. Notice that it doesn't go out farther than a week. Sometimes it doesn't even go that far. This is the only period in which they have confidence. Now read the discussion. In the discussion they talk about the various models, and how they are basing their forecast on them. Then they talk about "Long Term", which they consider to be three days from now. They break up the forecast into two different periods, based on confidence. But anything over a week and they don't even bother. Sure, there are models in which they can base a forecast, but they don't bother, because they know they are ridiculously unreliable.

Yet you seem to think that some long term model (or models) is extremely accurate, with little to no evidence to support it. Your only anecdotal example -- the basis of this post -- was completely wrong.

From Howard Specter the impact on California issued March 8th.

Quote:
Winter seems to be wrapping up with the present offshore trof that will bring snow showers and light amounts of snowfall accumulations. The two key periods seem to be Sunday as the off shore upper low settles south, and a deformation zone sets up over the Sierra and western Nevada. I would not expect much more than 1 to 3 inches from a pattern like this for Mammoth. There is another colder system headed our way as the long wave trof shift east for Tuesday into Wednesday. 1 to 3 inches…After that, high pressure aloft will begin to do its job the second half of next week. The ridge may not be strong enough to keep all the short wave energy out of the area, but it will keep any major storms out. Over time as we go through the third week of March….it appears to build even stronger.  Looking at the MJO, many of the models circle it around phases 3 and 4.  Phase 4 typically is dryer out west this time of the year while 3 can still produce some storminess. The Euro want to take it through and past the circle of death back into phases 8/1. That is the area of undercutting and that would typically brings us a warmer latitude storm track which California does not need. The timing for that should it occur is around the 20th.  BTW, The GFS does not not agree….it is more “Ridge City” as far as the eye can see….

However, the American Global Forecast System, ”GFS”, does really warm us up week 2 and that is concern enough because of the tremendous snow pack over the Sierra, especially in the mid elevations between 6000 feet and 8000 feet.  Flooding looks to become an issue at some point….

in the meantime, enjoy this weekend’s skiing and boarding at its finest, as spring skiing is on the way later this month.
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rossb
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PostMon Mar 11, 2019 6:15 pm 
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I have read your last post over and over and still don't know what your point is. Obviously there is great disagreement over what the long term forecast is for California (e. g. "The GFS does not not agree"). So much so that this forecaster can't commit to a forecast, obviously. He thinks there is a possibility of flooding, which makes sense, given the huge amount of snow that fell just recently, and the fact that it is California, and we are couple weeks away from Spring. He is doing his job, and raising the possibility that it might be a problem, but of course he hasn't called for a flood alert, the way he would if this were a short term forecast and the models agreed. California might flood. It might not. It might be stormy. It might be dry. This isn't exactly a revelation.
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Jumble Jowls
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PostMon Mar 11, 2019 6:39 pm 
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You've got to love REM.

That's great, it starts with an earthquake
Birds, snakes, and aeroplanes
Lenny Bruce is not afraid
Eye of a hurricane, listen to yourself churn
World serves its own needs, dummy serve your own needs
Feed it off an aux speak, grunt, no, strength
Ladder start to clatter with fear, fight down height
Wire in a fire, representing seven games
A government for hire and a combat site
Left of west and coming in a hurry
With the furies breathing down your neck

Team by team reporters baffled, trumped, tethered, cropped
Look at that low playing! Fine, then
Uh oh, overflow, population, common food
But it'll do
Save yourself, serve yourself
World serves its own needs, listen to your heart bleed
Dummy with the rapture and the revered and the right
Right
You vitriolic, patriotic, slam, fight, bright light
Feeling pretty psyched

It's the end of the world as we know it
It's the end of the world as we know it
It's the end of the world as we know it, and I feel fine

Six o'clock, TV hour
Don't get caught in foreign towers
Slash and burn, return
Listen to yourself churn
Locking in, uniforming, book burning, blood letting
Every motive escalate
Automotive incinerate
Light a candle, light a votive
Step down, step down
Watch your heel crush, crushed, uh-oh
This means no fear cavalier
Renegade steer clear!
A tournament, tournament, a tournament of lies
Offer me solutions, offer me alternatives and I decline

It's the end of the world as we know it
It's the end of the world as we know it
It's the end of the world as we know it, and I feel fine

It's the end of the world as we know it
It's the end of the world as we know it
It's the end of the world as we know it, and I feel fine

The other night I dreamt of knives
Continental drift divide
Mountains sit in a line, Leonard Bernstein
Leonid Brezhnev, Lenny Bruce and Lester Bangs
Birthday party, cheesecake, jelly bean, boom!
You symbiotic, patriotic, slam book neck, right?
Right!

It's the end of the world as we know it
It's the end of the world as we know it
It's the end of the world as we know it, and I feel fine

It's the end of the world as we know it
It's the end of the world as we know it
It's the end of the world as we know it, and I feel fine
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gb
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PostFri Mar 15, 2019 5:16 pm 
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rossb wrote:
gb wrote:
rossb wrote:
I think this is a great example of how unreliable long term forecasts are, and how important it is to not place too much faith in them.

What you are suggesting is that I made the forecast up, rather than watching forecast models.

Nonsense. Nowhere did I say "you made things up". I only said that you place way too much faith in long term forecasts. You don't seem to get it. Even meteorologists don't place that much faith in long term forecasts. Again, they are very confident in the short term forecasts. When they aren't confident, it shows up in the discussion. This means that lots of people (myself included) have great confidence in the short term forecasts when combined with the discussions. For good reason! They are almost always right. I would say 95% of the time, if not higher (thus my decision to give you ten to one odds). Are you really saying you would give ten to one odds on the long term forecast being correct? Seriously?

The lack of confidence explains why it is difficult to even find long term forecasts, or why meteorologists consider "long term" to be about a week, not a month. Even a week out the folks who make forecasts are a bit wary. It is not their focus. Why waste a lot of energy, when you know the models simply aren't that accurate?

Here, let me give you an example. Here is the main Northwest National Weather Service website (hosted by the UW). You can see gobs of information here. You can also see a ton of forecasts; most (if not all) are for a week or less.  Here is the zone forecast for the Northwest. Notice that it doesn't go out farther than a week. Sometimes it doesn't even go that far. This is the only period in which they have confidence. Now read the discussion. In the discussion they talk about the various models, and how they are basing their forecast on them. Then they talk about "Long Term", which they consider to be three days from now. They break up the forecast into two different periods, based on confidence. But anything over a week and they don't even bother. Sure, there are models in which they can base a forecast, but they don't bother, because they know they are ridiculously unreliable.

Yet you seem to think that some long term model (or models) is extremely accurate, with little to no evidence to support it. Your only anecdotal example -- the basis of this post -- was completely wrong.

You change the goal posts here. The discussion earlier was that forecasts basically could not be accurate beyond 4-5 days. Simply not true. But it depends on how realistic/unrealistic you are about long term forecasts. If there are the possibility of weather systems, they may be over or under forecast or may come in earlier or later than forecast. But in the above comments by you, you speak of both three days and seven days as being either the beginning of long term or the end of the ability to forecast. Of course, all of what you say above is essentially untrue. For one, depending on what exactly you expect the accuracy of forecasts to be, be it either long or short term, one to two day forecasts are not necessarily 95% accurate. It just depends on the synopsis and the dynamics involved. For an explicit example, Seattle got an initial unforecast snow storm - that would have been February 3rd, then it got another snowstorm of about 8" around February 9th. But, finally, the great fear of Seattle getting a snow depth of 16" after a third significant snowstorm, advertised for one by Cliff Mass, never happened. Of course, that was a very difficult forecast that became untrue because the Low Pressure area to our SW dug further offshore and put Seattle under warmer onshore flow, lifting the snow level to 1000-1500'. In fact anytime, summer or winter, that we are dealing with (threatened by in summer) semi-stationary or cut of Upper or Lower Level areas of Low Pressure, the exact track of the Low is largely unpredictable. This lead, with this third possible snowstorm, with successive forecasts expecting or not expecting snow in Central Puget Sound. In this situation, forecasts short or long term are very difficult.

However, as to the warming taking place today on March 15 and ramping up especially March 16 and 17 was pretty accurately forecast by March 8th and was even indicated to happen for this time period in the CPC discussion of February 21st and the update on February 28th. The only differences from March 8th to the current short term forecasts through the 17th are that Saturday will see a minor dip in the jet stream but with the only effect being increased clouds. Temperatures for the 17th, 18th, and 19th for 850 mb (which is what I look at) still look to be in the same range of +3 to +9 Celsius (rising through the period) - or freezing levels of approximately 7000 to 9500'. Sound familiar? By the 20th there is a one day weak front that did not initally appear, but temperatures rebound again for another 24-36 hours, before the weather will change in a way that is not yet obvious because of complexity by the 22nd or 23rd.

I agree wholeheartedly that for short or long term forecasts that watching the Forecast Discussions is the only way to go if you want an accurate forecast, no matter the length.

But yes, I am confident in long term forecasts to 7 days or even extrapolating beyond ten days in certain situations; this current transition representing a major jet stream repositioning, being one of them.

Another example, I know I left for Colorado on September 15th, so the last day I would have looked at models was September 14th. I was afraid of two things, monsoonal flow, and forest fire smoke primarily from the Northern California and SW Oregon wildfires, which remained active in this period. The monsoon seemed to remain confined to Arizona in this period although in Southwestern Colorado winds were forecast light southerly on nearly all of the days of my trip. The airflow at 5000' and 10,000' was Westerly in the Northern third of Colorado and across the Southern half of Wyoming and remained pretty consistent for the period. When I left, the 500mb pattern showed a slight dip and a small chance of precipitation in extreme Northern Colorado on what would have been September 23rd and September 24th +-. In fact, that system was stronger than forecast ten days out, and it rained for about 18 hours to just about the Southern 1/3 of Colorado. On a driving day it rained; that evening near Crested Butte it cleared.

When I left, the southerly flow along the Western Mountains of Colorado was forecast to remain Southerly most all the time, but it looked like there would be a short period around the time of the Crested Butte part of the trip that winds would switch to Westerly and could bring in smoke from fires mainly in Central Utah. In fact that happened. On the 26th at Telluride, it was the only day of the trip (and the end also) that there was appreciable haze visible.

I'd call that a pretty good forecast and it informed us on where to hike and what to expect in Colorado. The tools were initially Forecast Discussions and GFS Forecast models (at that time through Unisys out ten days), and the Windy website (for smoke), corroborated and extrapolated beyond the seven day forecast period of that site with, and just a bit beyond, the ten day forecasts of the GFS on Unisys. ( I currently use a different site that has forecast maps to 384 hours out).

So, contrary to your statements, short term and long term forecasts even to ten days or beyond can be very accurate in situations where you are dealing with significant jet stream patterns, in the absence of potentially important more small scale features, and when model forecasts indicate consistency over time.

Of course, all of this is esoteric at present. But it certainly wasn't on my trip last September to Colorado. If things did not look fairly reliably favorable, I would not have gone at all - at least not on an extended hiking trip.

The tools are there; the Forecast Discussion helps with guidance, and it takes practice but it is entirely possible to use forecasts for longer term forecast planning. With the resolution of the University of Washington MM5 short term models it is even possible to know one to two days out when rain will begin down to the hour. Overall, these are remarkable tools - and not that difficult to learn to use. I would not go on a longer trip if expectations were not for good weather, and in this day and age, also for avoidance of forest fire smoke.
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PostFri Mar 15, 2019 6:27 pm 
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I am not moving the goal posts. I have been very clear from the beginning, yet you keep making up stuff about what I'm saying. Read my comments again, and it should be clear. I don't know how else to say it, but I'll try again.

1) Official short term forecasts (a day or two away) are remarkably reliable.
2) Forecasts a week or so out are a bit less reliable, but still pretty good.
3) In both cases, reading the discussion that goes along with the forecast can lead to very reliable forecasts (95% or so).
4) Long term forecasts (about two weeks out) are generally unreliable.
5) Long term forecasts don't have much in the way of discussion, because they are unreliable (forecasters might mention the conflicting models, but even when they agree the forecasters aren't willing to put much faith in them).

I didn't want to get into Seattle snow forecasts, because my comments are long enough. But Seattle snow forecasting is simply an example of how important that third item is. If you read discussions of snow forecasting, you can see that. Just look at this thread: http://www.nwhikers.net/forums/viewtopic.php?t=8029099. That is the part of this that you seem to be missing. I never said that I could always make a good forecast. I only said that at various times, after looking at the forecast discussion and the official forecast, I can make a forecast with 95% (or better) accuracy. The forecast for that day was not one of those times.

In contrast, you have failed to make a good long term forecast, and the one time you went on a public blog, and put your reputation on the line, you failed. No one asked you what the weather was going to be like, but you felt confident enough to make a prediction.

And you were wrong. You didn't just miss, you missed by a mile. You missed by the longest amount possible! You said it would be much warmer than usual, and it was much colder than usual. You said we would have a pineapple express, and we didn't even have a papaya. As I have said repeatedly, I'm not trying to make fun of your ridiculously bad prediction, I simply want to point out that your methodology for making the prediction is ridiculously bad. You seem to latch on to one particular long range model and then just run with it. Any hesitation made by professionals seem to be ignored.

As I said before, the problem with that attitude, and spreading that attitude, is that it implies that other methodologies -- like the one using steps 1-3 above -- are similarly inaccurate. That is the part that is frustrating. I've only made one prediction, and it turned out to be quite accurate. I can make another prediction, which is that the weather really is changing. It will be warm this weekend, and into the beginning of next week. Want something more substantial? OK, here goes. I predict that temperatures on Monday will exceed 60 degrees, with no rain. This is much higher (and drier) than normal, thus well outside of climate norms (for this time of year). This would be a bold, risky prediction a couple weeks ago, but one that I feel confident giving right now. As before, I would give you ten to one odds for it being correct. If it rains, or never gets up to 60, then I would fork over $100, but if we have warm, dry weather, I win $10.

The thing is, I can make predictions like this quite often. Not all the time (sometimes the models disagree or there has been some change that makes the forecasters hesitate, and shows up in the discussion). But several times a month I can make a forecast like that, and I would be right around 95% of the time. How often do you really think you can make the same prediction for a long term prediction?
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PostSat Mar 16, 2019 12:55 pm 
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rossb wrote:
I am not moving the goal posts. I have been very clear from the beginning, yet you keep making up stuff about what I'm saying. Read my comments again, and it should be clear. I don't know how else to say it, but I'll try again.

Yes you have. Read your own post above - but go back a ways and you will see (must have forgotten what you and foist said - that forecasts beyond 4-5 days are not worthwhile.) In your last post you specifically said that forecasts beyond seven days are not reliable. In this post you say that that forecasts a "week or so out" are still pretty good". Below, you now pretend we are talking about forecasts two weeks out being "generally unreliable". Now we have the term "generally" inserted. You are covering here.

Quote:
1) Official short term forecasts (a day or two away) are remarkably reliable.
2) Forecasts a week or so out are a bit less reliable, but still pretty good.
3) In both cases, reading the discussion that goes along with the forecast can lead to very reliable forecasts (95% or so).
4) Long term forecasts (about two weeks out) are generally unreliable.
5) Long term forecasts don't have much in the way of discussion, because they are unreliable (forecasters might mention the conflicting models, but even when they agree the forecasters aren't willing to put much faith in them).

1) Short term forecasts are generally reliable, but also may not be. I gave an explicit example in my last post: "For an explicit example, Seattle got an initial unforecast snow storm - that would have been February 3rd, then it got another snowstorm of about 8" around February 9th. But, finally, the great fear of Seattle getting a snow depth of 16" after a third significant snowstorm, advertised for one by Cliff Mass, never happened. Of course, that was a very difficult forecast that became untrue because the Low Pressure area to our SW dug further offshore and put Seattle under warmer onshore flow, lifting the snow level to 1000-1500'. In fact anytime, summer or winter, that we are dealing with (threatened by in summer) semi-stationary or cut of Upper or Lower Level areas of Low Pressure, the exact track of the Low is largely unpredictable. This lead, with this third possible snowstorm, with successive forecasts expecting or not expecting snow in Central Puget Sound. In this situation, forecasts short or long term are very difficult." Furthermore, the University of Washington MM5 has generally been very reliable for me in forecasting rainfall, but it missed quite a bit in January on days I was out. For instance, I was out on January 26th at Redmond Watershed and the MM5 showed rain until 10 am and then not after. I told my students that forecast. Rather what happened was that rain begin around noon and continued, though light. I was also out near Darrington February 2nd and it was supposed to be mostly cloudy but was clear by 8AM. I don't disagree that short term forecasts are usually quite accurate, but the MM5 missed several times for me in January.

2) Long term NWS forecasts and the models themselves may or may not be accurate depending on the synopsis and dynamics involved. For instance, today beyond Tuesday (day 4) they are not reliable.

3) 95% is bs drawn out of a hat. The real situation is much more nuanced. But the Discussions are a good gauge of likely reliability because the Forecasters who do this for a living look at multiple models that are produced several times a day. When concerned or planning I might look twice a day, or when not active I might skip two three days. I might go with 60% for greater than 2-3 days but like you, that is also drawn out of a hat.

4) Long term, which you have now decided, to be 14 days, are of course, not generally reliable -but this depends on what you mean by reliable (as I said in my post), and it depends on the synopsis and dynamics in play. I gave two examples in my last post (which you chose to ignore) that on March 8th 2019 (and even before), the GFS model has proven very reliable for the forecast through March 19th, missed a week trough (still uncertain effects) on March 20th, but still shows reasonable accuracy March 21st and 22nd (ridge dominated, at times dirty). Overall, that is pretty dam good. I also gave you an explicit example in my last post of planning my trip to Colorado beginning September 15, 2018 for which I started studying about two weeks before. My last view of the model forecasts was September 14, 2018 and it was accurate (save for a weak trough that was 150 miles further south than forecast on September 24th, but was otherwise accurate to September 27th, including wind forecasts for smoke. That is again pretty dam good. So, the accuracy of long term forecasts - greater than 7 days or really 4-5 days is far more nuanced and is purely situational. Sometimes it is possible to have reasonable reliability and sometimes it is not. For instance, right now, I wouldn't bet a lick on a forecast (even crude) beyond March 22nd. In general, it will be cooler than present and may trend cooler until late in the month, and may be pretty wet or pretty dry, depending. It is too complex for accurate forecasting because of the positioning and shape of the trough and the tendency for higher pressure east.

5) Long term forecasts are only seldom mentioned in Forecast Office Discussions because in general they are not reliable, but also for most consumers they are not important. However, longer term CPC discussions, which are more generalized in geography and detail, include the opinions of a group of forecasters. I mentioned the CPC discussion of February 21, 2018 (updated but with little changes February 28,2018) that predicted a major jet stream switch the third week of March with the West Coast becoming significantly warmer and a long wave trough in the Midwest. It also hinted that it could get wetter the 4th week of March. You ignored that inconvenient detail.

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I didn't want to get into Seattle snow forecasts, because my comments are long enough. But Seattle snow forecasting is simply an example of how important that third item is. If you read discussions of snow forecasting, you can see that. Just look at this thread: http://www.nwhikers.net/forums/viewtopic.php?t=8029099. That is the part of this that you seem to be missing. I never said that I could always make a good forecast. I only said that at various times, after looking at the forecast discussion and the official forecast, I can make a forecast with 95% (or better) accuracy. The forecast for that day was not one of those times.

You didn't want to get into discussing the "snow forecast" because I gave the explicit example in my last post that only one of three snow events were accurately forecast as I repeated in number 1 above. It was not convenient for you to address this because it disproved your 95% rule. And a similar situation (as I stated in my last post)) summer or winter will not be accurately forecast either. It is far more nuanced and is situational. (Upper and Low Level Low Pressure especially when Cut-Off from the jet stream.)

Quote:
In contrast, you have failed to make a good long term forecast, and the one time you went on a public blog, and put your reputation on the line, you failed. No one asked you what the weather was going to be like, but you felt confident enough to make a prediction.

Either reading skills or honesty - don't know which - is not your strong suit. I gave two examples (Current and in Sept 2018) in the previous post and even used the word "Explicit example", and repeated them here under 4)


Quote:
And you were wrong. You didn't just miss, you missed by a mile. You missed by the longest amount possible! You said it would be much warmer than usual, and it was much colder than usual. You said we would have a pineapple express, and we didn't even have a papaya. As I have said repeatedly, I'm not trying to make fun of your ridiculously bad prediction, I simply want to point out that your methodology for making the prediction is ridiculously bad. You seem to latch on to one particular long range model and then just run with it. Any hesitation made by professionals seem to be ignored.

I said we could have a Pineapple Express and models show we could have have one again around March 26-28 (forecast but?). The Pineapple Express ended up being in Central Oregon to just North of the Bay area. Later models drifted it south day by day. You are obviously very angry in your last paragraph with all sorts of adjectives and adverbs. Get a grip. Did I miss because of model forecasts a forecast for early March, yes? But so what! I gave you two of accurate long term examples in the last post that I repeated in 4) above.

Quote:
As I said before, the problem with that attitude, and spreading that attitude, is that it implies that other methodologies -- like the one using steps 1-3 above -- are similarly inaccurate. That is the part that is frustrating.

What attitude? I use forecasts for my own use in planning and communicate them when they are interesting in my view. Why do you find that objectionable? This thread was begun with a song for entertainment and also because the recent cold period was so amazing and topical.

Quote:
I've only made one prediction, and it turned out to be quite accurate. I can make another prediction, which is that the weather really is changing. It will be warm this weekend, and into the beginning of next week. Want something more substantial? OK, here goes. I predict that temperatures on Monday will exceed 60 degrees, with no rain. This is much higher (and drier) than normal, thus well outside of climate norms (for this time of year). This would be a bold, risky prediction a couple weeks ago, but one that I feel confident giving right now. As before, I would give you ten to one odds for it being correct. If it rains, or never gets up to 60, then I would fork over $100, but if we have warm, dry weather, I win $10.

The thing is, I can make predictions like this quite often. Not all the time (sometimes the models disagree or there has been some change that makes the forecasters hesitate, and shows up in the discussion). But several times a month I can make a forecast like that, and I would be right around 95% of the time. How often do you really think you can make the same prediction for a long term prediction?

Good for you. But think about your ardent rhetoric and need to try to criticize. Your "bold" prediction for Monday was actually accurately forecast March 8th in models (to within 1-2 degrees C at 850 mb) I looked at, and broadly forecast/suggested in CPC Discussions February 21st.

The other purpose for this original post is to demonstrate to other more open-minded hikers/skiers/snowshowers/climbers that the tools are available for planning and that it is not that hard to use them. It just takes practice.
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PostSun Mar 17, 2019 1:16 pm 
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You seem more concerned with trying to find inconsistencies with what I've been saying, as opposed to actually understanding my claim. Meanwhile, you keep making things up, and twisting around what I say. I keep rephrasing it, and you keep returning to the same straw men (e. g. snow forecasts, which have nothing to do with anything I've said).

It is fairly simple. I can't always tell what the weather will be like, but quite often I can. Not 100% -- no one is perfect -- but around 95%. This is because I tend to focus on short term forecasts, and the discussion that surrounds them. Again, that does not mean I can always tell what the weather will be like. There are times when the weather is too unpredictable. But this shows up in the forecast discussions. So don't expect me to make a forecast every single day. But what I'm saying is that if I make a forecast, it is highly likely that it will be right. (Highly likely means 95% or better).

But I have no confidence in the least that you -- or anyone else for that matter -- is very good at making forecasts like the original one made in this post. You claimed that you knew what the weather was going to be like two weeks out. You had such extraordinary confidence that you posted it on this blog. This was not an "it might", but an "it will" forecast. Otherwise, why make it? Why come on the blog and say something like that, unless you have a lot of confidence. So either you simply didn't read the discussion about the long term forecasts (wherever that was), or you are putting way too much faith in them. Of course the long term forecasts are bound to be on target sometimes. They may even be better than simply flipping a coin. But you have given no evidence to support your case that you are capable of making those long term predictions with any reliability. In fact, you stumbled upon the opposite. You could have made a prediction at any time, and the one time you chose, it was a complete failure.

You also haven't answered my question about long term forecasts. How often do you think you can nail a long term forecast? 9 out of 10? 6 out of 10?
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