How do the weather guys do it

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
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west Texas
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Dave Taylor
It is Monday afternoon. In 48 hours we are supposed to see a very strong cold front here. I am looking at the current surface analysis and winds aloft and it is not obvious to me how the meterologists perform their craft. Here is a map of the US with my location annotated, plus a sketch of what the typical cold front looks like when it gets here.
Can anyone show me a NWS chart that has telltale indications of the approaching cold weather?

1.jpg
 
I think forecasting is as much science as it is art.. I think that's part of the reason why "they get it wrong" so often because even the most advanced modelling doesn't always predict it right

Looking at the chart below though (not sure if you already had this up) but it shows low pressure cold front just north of you with high pressure behind it. The symbols just over Texas would suggest that at least part of that front is moving, the but east and west of you it is stationary.. looking at this chart I think it is safe to assume that the high pressure north and west of you will eventually continue to push that low pressure cold front towards you

But again, I generally look at these enough to "become familiar" but will defer to the weather guys and FSS briefer for hard go/no go decisions

upload_2017-12-4_15-10-25.png
 
Well, that poorly defined cold front running over NM and up to MN (see photo above) has firmed up and started moving faster in this direction. The big high that you can see over the PacNW has combined forces with others inland to push in behind the cold front.

Looking at the nearest strong L which was west of the Great Lakes, I would have expected the cold air to move that direction but apparently this is driven by other things. The steering winds at 30K are mostly W to E behind the front.

Current situation below.
The cold air over the east side of the rockies is plunging south towards me as they predicted.
I would like to be better able to look at the charts 3 days ahead and see what they are seeing.

3.jpg
 
Not sure about your question, but it looks like it'll be bumpy as f in SoCal. Just look at that bad boy!
 
My uncle gave me some great advise when I was studying Economics. <-- yah, what does it have to do with anything I do now.

He said, "Forecast often, and only discuss your forecasts when you were right."
 
the 500mb chart is considered the "steering current" level.

so take a look at a current surface analysis, look at the 500mb chart and then try to guess what the surface analysis chart will look like in 12/24 hrs and then look and see what the 12/24 hr charts look like.
 
Ravioli said:
My uncle gave me some great advise when I was studying Economics. <-- yah, what does it have to do with anything I do now.

He said, "Forecast often, and only discuss your forecasts when you were right."
Click to expand...
Remember Harold Taft from KXAS Channel 5? Sounds like something he would say
 
jaybee said:
the 500mb chart is considered the "steering current" level.
so take a look at a current surface analysis, look at the 500mb chart and then try to guess what the surface analysis chart will look like
Click to expand...

Yes, that's what didn't work for me and I don't know why. See post #4. Must be interpreting it wrong.
 
Let'sgoflying! said:
Yes, that's what didn't work for me and I don't know why. See post #4. Must be interpreting it wrong.
Click to expand...

Sorry totally missed that.

Coriolis and surface friction have to be taken into account also as well as whats on the other side of the cold front, there was a High in Mexico for example. Just kind of got to guess and with time your guesses will get better.

Maybe sign up for - https://www.avwxworkshops.com/index_guest.php

or this is a link I really like that I hadn't visited in quite some time but I'm kind of a weather geek... - http://forecast.weather.gov/jetstream/matrix.htm in particular - http://forecast.weather.gov/jetstream/synoptic/ll_analyze.htm
 
jaybee said:
Coriolis and surface friction have to be taken into account also as well as whats on the other side of the cold front, there was a High in Mexico for example. Just kind of got to guess and with time your guesses will get better.
Click to expand...
Include Eötvös too
 
Ok, it is the 15th and since yesterday the wx gurus are calling for 12°F here on the 24th.
(10 days if you consider this has been out since yesterday)
What specifically are they looking at; use any charts or data to point this magic out to me.
 
Let'sgoflying! said:
Ok, it is the 15th and since yesterday the wx gurus are calling for 12°F here on the 24th.
(10 days if you consider this has been out since yesterday)
What specifically are they looking at; use any charts or data to point this magic out to me.
Click to expand...

A whole crap ton of computer generated models.

Which spit out charts like this.

64661f284a8ca4e617321f9f7a81cfee.jpg


They talk about their models a lot. And fondly. Like here...

http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html
 
Thanks.
So, no one is looking at these charts and giving the prediction.
A computer is doing it.
The ordinary pilot is hoping for too much if he thinks he can learn something this complex; something which a computer is generating.
(PS I compared the above text to the chart and do not see the first 3 things described)
 
Let'sgoflying! said:
Thanks.
So, no one is looking at these charts and giving the prediction.
A computer is doing it.
The ordinary pilot is hoping for too much if he thinks he can learn something this complex; something which a computer is generating.
(PS I compared the above text to the chart and do not see the first 3 things described)
Click to expand...

Oh lord no. The weather bureaucracy is massive. There’s all sorts of people looking at tons of models. And people writing models. And people debugging models. And people making charts from model raw data. And ...

Pretty much any pilot can look at the frontal map / surface analysis and decide if it’s going to be hot or cold, windy or calm, and flyable or not, with practice.

You seemed to want to know how they came up with temperature probabilities down to specific temperatures, and that’s a whole lot different than just looking at the map for a general weather pattern.
 
denverpilot said:
You seemed to want to know how they came up with temperature probabilities down to specific temperatures,
Click to expand...
oh, no. I can see what the weather is doing tomorrow or the next day from the charts, to some degree. I wanted to extend that out to 5 days - I thought there might be some simple techniques to use to accomplish that. But it's looking more like a complex calculation or algorithm is used.
 
Let'sgoflying! said:
oh, no. I can see what the weather is doing tomorrow or the next day from the charts, to some degree. I wanted to extend that out to 5 days - I thought there might be some simple techniques to use to accomplish that. But it's looking more like a complex calculation or algorithm is used.
Click to expand...

Yeah, definitely. My nephew had us over to his pad recently, he’s a mechanical engineer and doing the millennial thing of having a pile of roommates and a really really nice townhouse with lots of bedrooms, and a shared living area. Way nicer than my first apartment.

Got to talking to one of his roommates, and he writes the math papers that get the models written by the software people. He’s moving next year to go do some work at Norman, OK at the NSSL. Obviously a brilliant guy. His thesis work was on supercooled water droplets and in flight icing.

Very cool that the smart nephew hangs out with other super smart people, and has a pad with them. They all spend some of their savings in co-habitation on nicer cars than I could afford at that age, too. LOL. Pretty proud of that young guy. He’s doing well for himself, and does neat engineering projects in his job, too. He’s into robotics but it’s not his primary day job. If I was building a robot, I’d probably bend his ear a lot. ;)
 
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