Jump to content
  • Member Statistics

    17,600
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

PHL Jan 11-12 Regional Obs Thread


blue sky

Recommended Posts

  • Replies 850
  • Created
  • Last Reply

The only word of caution about the CoCoRaHS gauge is that once you get more than about 6" of snow you can start to decrease catch, since it tends to pile up more on one side of the gauge much of the time thanks to the wind. I was glad that the snow was split almost evenly around midnight back home, so my parents could just swap out the gauge at midnight, let it melt, and then swap them back again in the morning to allow the other one to melt.

Link to comment
Share on other sites

The only word of caution about the CoCoRaHS gauge is that once you get more than about 6" of snow you can start to decrease catch, since it tends to pile up more on one side of the gauge much of the time thanks to the wind. I was glad that the snow was split almost evenly around midnight back home, so my parents could just swap out the gauge at midnight, let it melt, and then swap them back again in the morning to allow the other one to melt.

so you recommend having a spare?

Link to comment
Share on other sites

The only word of caution about the CoCoRaHS gauge is that once you get more than about 6" of snow you can start to decrease catch, since it tends to pile up more on one side of the gauge much of the time thanks to the wind. I was glad that the snow was split almost evenly around midnight back home, so my parents could just swap out the gauge at midnight, let it melt, and then swap them back again in the morning to allow the other one to melt.

Oh, and with snow, unless you will just wait til its all done, having a second gauge helps a lot.

Link to comment
Share on other sites

Absolutely. Makes it much easier in the winter. I have two here in Elko, and my parents have two. At the NWS office we also have a two of the 8" gauges, so we just swap them out when we go measure.

for the snowfall in tenths, couldnt you just use a drafters ruler? Im pretty sure they have a 1/10th scale.

Link to comment
Share on other sites

It depends. Sometimes the heated gauges do better than other times, but not necessarily due to wind. TTN ASOS's heated tipping bucket only recorded 0.27", about half what my parents melted down.

I recorded 0.59" to 7.3" today, 2.2" to 0.14" on Friday's event. Worked great. In the Blizzard, not so much! 0.45" != 31.8" snow.

Link to comment
Share on other sites

for the snowfall in tenths, couldnt you just use a drafters ruler? Im pretty sure they have a 1/10th scale.

The measuring stick I have is 36" divided into tenths. It is made of a thin metal which allows it to slide into the snow with little disruption to the snow pack. It also makes it easier to break through a hard crust layer. Got if from a friend who is a NWS Coop Observer a number of years ago.

Link to comment
Share on other sites

The measuring stick I have is 36" divided into tenths. It is made of a thin metal which allows it to slide into the snow with little disruption to the snow pack. It also makes it easier to break through a hard crust layer. Got if from a friend who is a NWS Coop Observer a number of years ago.

Just a note:

If the hard crust layer ever gets too hard that you really can't get the stick into it, it's better to bring a screw driver and/or hammer with you, and break some of the ice, rather than bending your stick.

Link to comment
Share on other sites

The only word of caution about the CoCoRaHS gauge is that once you get more than about 6" of snow you can start to decrease catch, since it tends to pile up more on one side of the gauge much of the time thanks to the wind. I was glad that the snow was split almost evenly around midnight back home, so my parents could just swap out the gauge at midnight, let it melt, and then swap them back again in the morning to allow the other one to melt.

For all-snow situations, we (NJ CoCoRaHS) always suggest taking a core sample versus gauge-caught snow. Of course, when there's rain mixing in or melting of the snow that fell, all bets are off.

Link to comment
Share on other sites

The boldened is why I don't advocate that a whole lot.

Well, another option is to try both the gauge-caught and core methods, and then use the larger value. Sometimes those gauge-caught reports when there's some wind involved are surprisingly low.

Link to comment
Share on other sites

when taking a core sample, how do you handle old snow vs. new snow?

Use a snowboard (a piece of plywood painted white) to measure new snow. Each day (well, if we were so lucky to get snow each day), you clear it and only measure new snow on it.

Regarding the "each day" part, there are some who clear their boards more often (every 6 hours, for example) during a storm, but I prefer letting it accumulate.

Link to comment
Share on other sites

Use a snowboard (a piece of plywood painted white) to measure new snow. Each day (well, if we were so lucky to get snow each day), you clear it and only measure new snow on it.

Regarding the "each day" part, there are some who clear their boards more often (every 6 hours, for example) during a storm, but I prefer letting it accumulate.

so you suggest taking a core sample from the snowboard (which I use) as opposed to taking it from the snow accumulated in the outer portion of the gauge

Link to comment
Share on other sites

so you suggest taking a core sample from the snowboard (which I use) as opposed to taking it from the snow accumulated in the outer portion of the gauge

It depends. For a snowfall in calm conditions, you'd probably do just fine using what fell in the gauge (assuming it didn't overflow). When you start introducing wind, it gets tougher to get a reasonable measurement from the gauge. Often what I'll do is melt both the gauge-caught and core sample, see how they compare, and then go with what seems more realistic. But if you use a core, you want to be sure that the snow on your board is representative of what fell (I guess the same can be said for where the gauge is located). And again, when there's suspected melting of snow off the board or mixing with rain, your gauge-caught sample is your best bet.

Just my opinion, which was largely formed from guidance from my colleague who is a snow measuring expert. Ultimately, the observer uses his/her discretion to decide what's best!

Link to comment
Share on other sites

It depends. For a snowfall in calm conditions, you'd probably do just fine using what fell in the gauge (assuming it didn't overflow). When you start introducing wind, it get's tougher to get a reasonable measurement from the gauge. Often what I'll do is melt both the gauge-caught and core sample, see how they compare, and then go with what seems more realistic. But if you use a core, you want to be sure that the snow on your board is representative of what fell (I guess the same can be said for where the gauge is located). And again, when there's suspected melting of snow off the board or mixing with rain, your gauge-caught sample is your best bet.

Just my opinion, which was largely formed from guidance from my colleague who is a snow measuring expert. Ultimately, the observer uses his/her discretion to decide what's best!

thank you for taking the time to explain. I value your expertise. I just want to make sure I "follow proper protocol" when measuring!

Link to comment
Share on other sites

Well, another option is to try both the gauge-caught and core methods, and then use the larger value. Sometimes those gauge-caught reports when there's some wind involved are surprisingly low.

It helps to have a nice sheltered location to measure (both snow and precip). There are some places where you probably just simply shouldn't be measuring. Sadly, the NWS office here is probably among those, seeing as we are on an exposed hill...

Link to comment
Share on other sites

I just got a note from someone in the Philly media (I know the name and affiliation but won't share here to protect their innocence ;) ) saying

"I was following the storm posts last night, and yours were dead-on. Nice work."

So at least someone enjoyed what I had to say :thumbsup:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...