Is SKEW-T still important to soaring pilots ?

At 13:35 01 March 2016, wrote:
Papa3, what is HRRR ???

High Resolution Rapid Refresh - A browser for viewing weather data
in a graphical form

On Monday, February 29, 2016 at 8:33:35 PM UTC-5, Papa3
wrote:
Well... the SKEW-T logP is one of the most information rich
diagrams one
=
can find. If you know how to really "read" one, you can figure out
lift
st=
rength, height, cloudbase, and winds from a single view at a
glance. It
ta=
kes me about 5 seconds to look at one to decide if it's a good day
or not.
=
That said, the modern interfaces in XCSkies, DrJack, etc. allow
you to
ge=
t a broader view of weather at a macro level including fantastic
trend
info=
rmation. "North looks like it should have higher bases and more
Cu than
S=
outh" or "it's obvious that the models think the encroaching front
shuts
th=
ings down by late afternoon." HRRR is becoming incredibly useful
for my
fo=
recasting as well. =20
=20
So, the answer for me is "Yes, it's still very important." But
since
the=
y are a point forecast, they aren't the only thing I look at.

Not just a "browser" but a fundamentally different model. It's been exceptionally useful in task setting giving resolution down to very fine level. UI takes some getting used to, but you only care about a couple of values anyway.

http://ruc.noaa.gov/hrrr/

I've been using skew-T to get better at 'reading the sky'.

1)Look at sky. Imagine what skew-T should look like. Look at skew-T.

2)Look at Skew-T. Imagine what sky should look like. Look at sky.

Fun and fascinating.

A quick look shows a resolution of the whole USA...Will try to find finer resolution after work. Dan
On Tuesday, March 1, 2016 at 2:28:53 PM UTC-5, Papa3 wrote:
Not just a "browser" but a fundamentally different model. It's been exceptionally useful in task setting giving resolution down to very fine level. UI takes some getting used to, but you only care about a couple of values anyway.

http://ruc.noaa.gov/hrrr/

Yes, being able to read a Skew-T is still important
IF
you want to do a reasonably accurate job of Forecasting for cross country or competitive flights.
IF
all you want to do is fly around the airport, or decide to make instructional flights, looking at the pretty colors is good enough.
Why?
Well XC Skies only generates the pretty colors every three hours. That makes it pretty hard to predict the beginning, and end of the day with reasonable accuracy. Model Update times on the sites with pretty colors lag what's available directly from http://rucsoundings.noaa.gov/. If you make an early morning forecast on the east coast, update time is important, and having one available every hour is important if you want to know when to launch and when to land. Model selection...All the models are lying to you, too some degree. The question is which one of them is lying to you the least? The most reliable model for this air mass, today, may not be available on the sites with the pretty colors.
I have not tried Topmeteo, but plan on doing so this spring. If the only model it uses is the NAM, we may have problems with it on the east coast. On the day of the flight the NAM is not your usual best choice of weather model to look at. Its pretty much all you have looking three days out (along with the GFS), but it's not known to be all that accurate for this afternoon.

Looking at the pretty colors is better than doing nothing, combine that with a quick look at the satellites for clouds, and the mixing height, and winds on the NOAA tabular forecast, and you will have something reasonably OK.



SF

HRRR
At the top is Domain: Full.
Choose your region there.
Jim


On Wednesday, March 2, 2016 at 10:13:51 AM UTC-8, wrote:
A quick look shows a resolution of the whole USA...Will try to find finer resolution after work. Dan

Looks very impressive indeed. What typical values do you use for your task setting ? Dan
On Tuesday, March 1, 2016 at 2:28:53 PM UTC-5, Papa3 wrote:
Not just a "browser" but a fundamentally different model. It's been exceptionally useful in task setting giving resolution down to very fine level. UI takes some getting used to, but you only care about a couple of values anyway.

http://ruc.noaa.gov/hrrr/

Not comprehensive, but:

- Planetary Boundary Layer (PBL) height
- Total cloud cover
- Low level cloud cover
- Lifted condensation level (LCL)
- Winds (10M, 850MB)

In particular, the HRRR seems to do an excellent job of handling clouds, both convective and upper air. For instance, if you're worried about a forecast cirrus shield moving in (or out), I've found that the Total Cloud cover really helps develop that situational awareness. "Looks like the north area might get shut down later, let's task the fleet there early and get them back to the south before it starts shutting down". Also very useful to use the cloudbase calculations from XCSoar or DrJack. On ridge days provides detailed view of wind field.

P3

P3, have you found Windyty or ye olde Nullschool useful on ridge days?
Jim

WindyTy is very "pretty", and it gives a great synoptic view of winds and the associated system. In fact, the UI is probably as good/better than anything out there for wind depiction over time. But, it's limited by the fact that the underlying model is only the GFS. Hopefully Walt Rogers will chime in here, but if someone ever wanted to do a project to create the ultimate forecasting tool for gliding, I think it would include meso-scale visualizations (like WindyTy, Dr.Jack) with point-forecast SkewT and related parcel analysis across models (like Bufkit or Bill Moninger's parcel analysis tools) as a point-and-click drill down. The way I think about forecasting for gliding is:

- Big picture/synoptic. Do I even need to dig deeper (along the lines of Doc's Weather forecasting rock if you recall: Rock is wet - it's raining, Can't see rock - it's snowing, Rock is gone -it's windy). Once I know whether it's worthwhile then...

- Meso-scale visualizations. I use Dr. Jack (NAM), HRRR, etc. to get a more detailed picture (lift strength and heights, clouds/cloudbase,wind direction and strength which quadrants look better, etc.)

- Point analysis: If I'm serious about the day, I look at Bufkit or just use the Moninger (Rucsoundings) sight to see what the underlying SkewT looks like, often comparing models. That last bit is important, as we are seeing more and more days here in the east where the models (GFS, NAM, RAP, HRRR) are diverging in one or more critical parameter. So, being able to compare and check for consistency also help instill confidence in the forecast.

Long answer to a short question.

p3