[gradsusr] Confusiong about WEASDSFC, GFS

[Christopher Gilroy]

Ahh, yea I just do the programming for a degree'd met. He wanted to base a
formula around 2m tmp, 700mb temp and 850mb temp. That's an interesting
link too.



On Tue, Sep 29, 2015 at 9:21 AM, Stephen McMillan <smcmillan at planalytics.com
> wrote:

> Chris,
>
> I suppose there are a number of vertical-temperature based
> formulas/algorithms out there, one of which is the Kuchera method which
> uses an algorithm based, in part, on the max temperature between 500mb and
> the surface  It seems to work fairly well for most scenarios.   Here's a
> link for more information:
> http://www.wxcaster.com/gfssnow.txt
>
> Hope that helps--
> Stephen Mc
>
> On Tue, Sep 29, 2015 at 9:11 AM, Christopher Gilroy <
> chris.gilroy at gmail.com> wrote:
>
>> Hey Stephen,
>>
>> Thanks for your response I figured that out after the fact. I appreciate
>> the help you've given me with this the past few days. One last question I
>> have to throw out there, what would your thoughts be on having a "dynamic"
>> ratio based on vertical temperatures? Do you think it'd be wildly
>> inaccurate or? I seen Ryan Maue make a comment one time about it causing
>> confusing and/or being great for certain areas but terrible for other areas.
>>
>> On Tue, Sep 29, 2015 at 9:07 AM, Stephen McMillan <
>> smcmillan at planalytics.com> wrote:
>>
>>> Chris,
>>>
>>> If you want to convert amounts in mm to in, you need to divide by 25.4,
>>> not 2.54 (or, multiply by the 0.03937 you had in your example).    To go
>>> the other way (in to mm), multiply in. amounts by 25.4.
>>>
>>> However, if you are converting mm to in. and using a 10:1 snow-liquid
>>> ratio, then simply dividing the weasdsfc amounts by 2.54 should achieve the
>>> same result as dividing by 25.4 (multiplying by 0.03937) then multiplying
>>> result by 10.  Result would be in inches.
>>>
>>> Stephen Mc
>>>
>>>
>>>
>>> On Tue, Sep 29, 2015 at 8:41 AM, Christopher Gilroy <
>>> chris.gilroy at gmail.com> wrote:
>>>
>>>> Alright, I have two primary questions, and if the answers are yes to
>>>> both, the follow-up makes no sense to me.
>>>>
>>>> 1.) weasdsfc is water equivalent based in mm, correct?
>>>> 2.) weasdsfc has no "default" liquid:water ratio, correct? A
>>>> meteorology friend of mine said 'typically' 10:1 is a good standard, so I'm
>>>> unsure if the model is based around that or not?
>>>>
>>>> I'm fairly certain I'm correct on #1. I'm unsure on the other 2 though,
>>>> but here's my current situation. If I use the expression below:
>>>>
>>>> 'd
>>>> const((sum(maskout(weasdsfc-weasdsfc(t-1),weasdsfc-weasdsfc(t-1)),t=2,t='%i%')/2.54),
>>>> 0, -u)'
>>>>
>>>> I get an identical looking map as another well known sites 10:1 snow
>>>> accum, in inchs. The confusion part of that equation should be converting
>>>> (/2.54) IN to MM, no?
>>>>
>>>> Now, if on the other hand I do the (if I'm understanding this right)
>>>> "correct" calculation to convert mm to in:
>>>>
>>>> 'd const((sum(maskout(weasdsfc-weasdsfc(t-1),weasdsfc-
>>>> weasdsfc(t-1)),t=2,t='%i%')*0.039370), 0, -u)'
>>>>
>>>> I get very, very, very little snow plotted.
>>>>
>>>> Now, I am using the sflux files instead of the pgrb2.0p25 files, which
>>>> I thought the flux files maybe used different units or something but they
>>>> don't, weasdsfc is still [kg/m^2] which should mean (unless my
>>>> expression is more of a hack than I would have imagine) I should be getting
>>>> the opposite outputs of what each expression is actually producing?
>>>>
>>>> I don't know if I'm missing a parenthesis group somewhere and I'm
>>>> somehow getting an inches, 10:1 snow accum plot with my code by "accident"
>>>> or what? :-/
>>>>
>>>> _______________________________________________
>>>> gradsusr mailing list
>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> -Chris A. Gilroy
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>


-- 
-Chris A. Gilroy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20150929/e79af5ff/attachment.html