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Wet snow Monday Dec 14, 2020?


wdrag
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24 minutes ago, wdrag said:

Ditto this part of Wantage Nj ~740'MSL  1PM 6 hourly...deck cleared for new snow after the first 6 hr total was 0.9"  Pavement 1/3rd" wet slushy. 33.4F   gentle 1 to 1.5Mi s-. 

Is that the official way to measure snow depth, clear measuring area every 6 hrs? I usually just stick a yardstick  in it at the end.

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4 minutes ago, IrishRob17 said:

This is always a big debate each winter, whether to clear the board every 6 hours or at the end of the event or 24 hours, whichever comes first. 

Have you tried both methods on the same board? 1/2 of the board one method and the other 1/2 the other method?

that might be interesting too see the results with different snow ratios and P type changes thru different events.

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7 minutes ago, sussexcountyobs said:

Is that the official way to measure snow depth, clear measuring area every 6 hrs? I usually just stick a yardstick  in it at the end.

I say that you are doing it correctly and @NorthShoreWx  would agree, hoping Walt chimes in on this.  Here are the guidelines: https://www.weather.gov/media/coop/Snow_Measurement_Guidelines-2014.pdf

5 minutes ago, hudsonvalley21 said:

Have you tried both methods on the same board? 1/2 of the board one method and the other 1/2 the other method?

Same brain, I have two boards so I'm going to try this.  

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21 minutes ago, hudsonvalley21 said:

Have you tried both methods on the same board? 1/2 of the board one method and the other 1/2 the other method?

that might be interesting too see the results with different snow ratios and P type changes thru different events.

Unfortunately the NWS eliminated the clear the board every 6 hours.  If it stops accumulating and then melts, does that mean we measured nothing?  I understand with a continuous heavy snowfall, not clearing the board measures the actual snow depth, compression and all.  I'm okay with that.  Otherwise you can "measure" 35" of what actually fell, and only have 26" on the ground (for example).

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11 minutes ago, Dark Star said:

Unfortunately the NWS eliminated the clear the board every 6 hours.  If it stops accumulating and then melts, does that mean we measured nothing?  I understand with a continuous heavy snowfall, not clearing the board measures the actual snow depth, compression and all.  I'm okay with that.  Otherwise you can "measure" 35" of what actually fell, and only have 26" on the ground (for example).

No, per the document Rob linked to:

"This measurement should reflect the greatest accumulation of new snow observed (in inches and tenths, for example, 3.9 inches) within the past 24 hours even if this total occurs at a time preceding the regularly scheduled observation time."

So the goal is to get as close as possible to maximum depth from the event, OR to clear and measure after 24 hours, if required.

That said, everyone seems to have their own methodology. I follow the above guideline except (for my personal records) in situations where additional snowfall is expected to follow a temporary p-type change. So if I get 3", then a period of rain, then another 3", with depth never exceeding 4", I'll record it as 6" instead of 4". Again, though, I adhere to the standard protocol more closely when reporting to the NWS.

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33 minutes ago, IrishRob17 said:

I say that you are doing it correctly and @NorthShoreWx  would agree, hoping Walt chimes in on this.  Here are the guidelines: https://www.weather.gov/media/coop/Snow_Measurement_Guidelines-2014.pdf

Same brain, I have two boards so I'm going to try this.  

I've been doing the max depth thing, although I will wipe a board once a day in the AM , even during a continuing storm.  That's the number I provide in spotter reports.  I double it for posting here.

To be fair that doc leaves open the possiblity for 6 hour wipes (i.e., at airports), so the issue remains confusing,  I'm not sure if it is the latest and greatest however.

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20 minutes ago, NorthShoreWx said:

I've been doing the max depth thing, although I will wipe a board once a day in the AM , even during a continuing storm.  That's the number I provide in spotter reports.  I double it for posting here.

To be fair that doc leaves open the possiblity for 6 hour wipes (i.e., at airports), so the issue remains confusing,  I'm not sure if it is the latest and greatest however.

Typically CO-OP stations and CoCoRAHS sites measure 1x/day...max depth on the board since the prior morning ob.

 

However,  more accurate snowfall that limits settling-drifting etc is taken every 6 hours with a snowboard wipe. 

Snowfall:

Measure and record the greatest amount of snowfall that has accumulated on your snowboard (wooden deck or ground if board is not available) since the previous snowfall observation. This measurement should be taken minimally once-a-day but can be taken up to four times a day, (every 6 hours) and should reflect the greatest accumulation of new snow observed (in inches and tenths, for example, 3.9 inches) since the last snowfall observation.

Here's the link. https://www.weather.gov/gsp/snow

 

Hope this helps.  Walt

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19 minutes ago, wdrag said:

Typically CO-OP stations and CoCoRAHS sites measure 1x/day...max depth on the board since the prior morning ob.

 

However,  more accurate snowfall that limits settling-drifting etc is taken every 6 hours with a snowboard wipe. 

Snowfall:

Measure and record the greatest amount of snowfall that has accumulated on your snowboard (wooden deck or ground if board is not available) since the previous snowfall observation. This measurement should be taken minimally once-a-day but can be taken up to four times a day, (every 6 hours) and should reflect the greatest accumulation of new snow observed (in inches and tenths, for example, 3.9 inches) since the last snowfall observation.

Here's the link. https://www.weather.gov/gsp/snow

 

Hope this helps.  Walt

I'd just add that this page is a bit outdated, since it allows for 6-hourly board clearings. Current NWS guidelines have removed that option, unless specifically requested from your local WFO (e.g., airport stations). See pages 6-9 here: 

https://www.weather.gov/media/coop/Snow_Measurement_Guidelines-2014.pdf

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49 minutes ago, NorthShoreWx said:

I've been doing the max depth thing, although I will wipe a board once a day in the AM , even during a continuing storm.  That's the number I provide in spotter reports.  I double it for posting here.

To be fair that doc leaves open the possiblity for 6 hour wipes (i.e., at airports), so the issue remains confusing,  I'm not sure if it is the latest and greatest however.

You're doing it perfectly right. This is the same that we advocate in CoCoRaHS (I coordinate the NJ program). And yes, also doubling for posting here. 

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Yeah that 24 hour number is going to be wrong too often around here. Sure maybe if it's 16 degrees with no wind and perfect antecedent conditions it will give you a close enough reading but here that will frequently leave you with half or less compared to what actually fell. I don't make official reports but will continue to use the max depth numbers for myself and my entertainment and will modify the timing on checking that depth as the temp and p-type fluctuates throughout a storm because it's almost never consistent here.

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