Winter forecast.... (12-13 February 2012)

[Brian Davidson]

So the local weather says snow after midnight on Sunday "monday morning". I'm looking at the models and I think snow wont start to fall till Monday morning around 5am". I know this is after midnight but you would think they would leave out Sunday Night getting snow and just add Monday morning. I know I'm not the NWS but i'm just confused in what the models are telling me.

Here is the 2am run:

Are you can see on the left image, the dewpoint is a good 10 degrees colder than the air temp.





Here is the 5am run:

as you can see, you have complete saturation around -5. I'm guessing this wont be complete snow but a wintery mix. The reason for this is that around 10,000 feet the air temperature is above the freeze line.


Please help, thanks!

 

[Brian Davidson]

bah, I just noticed there is a winter weather section. If a mod sees this, sorry! Your also free to move it to the right section.

 

[rdale]

I notice your timeline is off by an hour, 12Z = 6am CST. You'll need to adjust that. Also realize that is just raw model output, they may not agree with the timing of precip initiation.

Regarding ptype - at no place, especially at 10000ft, is the temperature above freezing.

 

[Brian Davidson]

Thanks for the reply. There are two times at the bottom. One time tells you the model run "left side" and the other tells you local time "right" "2am/5am":
Here is a larger image of the two runs from last night. Also, the temp at the bottom is in Celsius "I think? This is based of local temps being around the freezing mark"

1. 2am "no snow"

2. "5am/ snow/wintery mix?!"

....




I'm looking at the new runs and they have not changes a lot. The only thing they did was bump up my prediction an hour to 4am.













I'm still new to forecasting so if I'm wrong, let me know and why. Thanks!

 

[rdale]

Again you are off by an hour, you need to go to the profile page and fix your time.

The 0 is the freezing line (0* C) but it goes up and to the right. The red line is always to the left (below freezing.)

I think the bigger issue is that you're trying to decode model data before you understand the weather behind it... Check https://www.meted.ucar.edu/training_module.php?id=225

 

[Brian Davidson]

ahh, I see that now... thanks!

Also, I think my time is correct. I went into settings and it says west by 6hours. Is this not correct for central time?

 

[Patrick Marsh]

ahh, I see that now... thanks!

Also, I think my time is correct. I went into settings and he says west by 6hours. Is this not correct for central time?

It is, but check to see if you have a Daylight Savings Time issue. Because 10Z is 4AM in Central Standard Time. (10 - 6 = 4).

 

[GPhillips]

Also, I think my time is correct. I went into settings and he says west by 6hours. Is this not correct for central time?

Make sure "DST in Effect" is not checked in the setup screen. For help in the interpretation of skewT diagrams, you should definitely go through the training module rdale linked.

Edit...Patrick beat me to it.

 

[Brian Davidson]

I don't have a "DST in Effect" option =/ I guess I will just have to wait a few weeks for it to be right lol

 

[rdale]

On the profile screen go to the last tab where you can adjust the time.

 

[Andrew Francis]

Pretty decent precip. shield moving through TX right now.

Currently 33F here in N OKC and the sun just came out. Looks like the timing of precip entering into C OK will be right about sunset when we fall back to 31-32. If the precip keeps filling in like it is right now, I would suspect slightly higher amounts than what was forecast here. This storm's precip bulb is fairly healthy looking for how weak it is/was forecast to be.

 

[Brian Davidson]

Theses are my options,

I don't see anything about DST =/

thanks again for the help!

 

[rdale]

That's not the overview screen. Please load up the overview view, and on the last tab is a section to adjust time. There is no DST setting in the program itself.

 

[GPhillips]

That's not the overview screen. Please load up the overview view, and on the last tab is a section to adjust time. There is no DST setting in the program itself.

There is in the latest version. I assumed he had that but was obviously mistaken.

http://wdtb.noaa.gov/tools/BUFKIT/

 

[rdale]

You're right and I misspoke - I meant to push him towards the overview window where he can change the time. That's where his issue lies, regardless of DST setting.

But good catch, I see from his snapshot that he's on an old version.