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Isotherm

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Everything posted by Isotherm

  1. Agree, and I'd argue the once per day observation is the least accurate of all for sure. The clearing/vs maximum depth should be fairly similar in most storms that aren't > 32F at the surface.
  2. It's definitely a mess now. I'm not sure why there aren't clearer instructions disseminated.
  3. Correct. This is per Matt G who works with the State Climatologist. "One final thing regarding this past event. We did receive a 31.0" storm total snow report in Kinnelon (Morris County, NJ) that no doubt got at least a little attention, as it would represent, as far as I know, the largest event total in NJ from the storm. I checked in with the observer, and he confirmed that he cleared the board 3 times mid-storm to reduce the effects of compression. Unfortunately, that makes his inflated measurement invalid, at least in the context of the current guidelines (though even with the 6 hour rule, this must have been more like 1 hour clearings), so we've nixed the value. BTW, I'll personally be working on crafting a NJ snowfall map tomorrow based on hundreds of reports received. I post it here when complete."
  4. Prior to 1998, it was max-depth unless instructed. I think max depth would maintain more congruence w/ historical record. I've previously provided reference to the current NWS guidelines. I checked with the NJ State Climatologist, who specializes in snow cover and was very much involved in the crafting of the guidelines. What he was able to explain to me was that traditionally, the six hour option has only been available to professional observers at airports. However, back in about 1998 the NWS rules were revised and the six hour option was added for Coop observers*.
  5. Per the NJ state climatologist: "When things were reconsidered in 2012, the 6-hour option was removed except for "when instructed." Now, I'm not sure of the frequency of this usage, but apparently the 6-hour option is not in use, only when instructed to do so by the NWS (usually airport).
  6. They're not supposed to as per official guidelines. They should be taking intermediate depth measurements to capture maximum depth. Unfortunately, there is a ton of miscommunication on this issue. NWS airports do use it sometimes when advised (See last post).
  7. Just as an FYI, the latest NWS/COOP guidelines for measuring snowfall are to take the maximum accumulation of new snow in a 24 hour period. The 6 hour clearing method is no longer in effect, unless specifically instructed to by a NWS office (airports sometimes). See the following: section 3.1 and onward http://www.nws.noaa.gov/os/coop/reference/Snow_Measurement_Guidelines.pdf The following is courtesy of Matt G. who operates with the New Jersey State Climatologist, regarding the official guidelines: I've previously provided reference to the current NWS guidelines. I checked with the NJ State Climatologist, who specializes in snow cover and was very much involved in the crafting of the guidelines. What he was able to explain to me was that traditionally, the six hour option has only been available to professional observers at airports. However, back in about 1998 the NWS rules were revised and the six hour option was added for Coop observers*. This was despite the protest of several people on the committee, as a higher up (I won't name names, but any snow weenie will know the name well) overrode them. When things were reconsidered in 2012, the 6-hour option was removed except for "when instructed." The same fellow who brought about the 6-hour allowance, oddly enough, signed off on the removal of the 6-hour option. All that said, the biggest debate on the committee related to the snow->melt-> snow in a single day situation, the same occurrence that has been argued about here. Ultimately, the compromise was made to simplify the guidelines and call daily snowfall the maximum accumulation achieved during a day, period. There's arguments to made both ways (and it sounds like there were among the experts on the committee), but ultimately, the guideline is objective, consistent, and most in line with historical practices. All that said, from what I've seen as a heavy user of Coop data and a state coordinator for CoCoRaHS, far and away the most common "problem" with snow measurements is that many observers (and from what I've seen, perhaps the majority of non-airport Coop) take their measurements once daily at ob time without making any attempt to capture the maximum accumulation. This is probably not a new issue, as I bet it's been relatively common through the years. But sometimes the differences between maximum accumulation and ob time measurement can be significant, so this is something I gently remind volunteers about, with the understanding that many are unable (e,g., at work or sleeping) or unwilling to take these extra measurements (some Coop sites, for instance, are businesses or municipal operations centers, thus not manned all day). It sucks, but we live with it. As for frequent board clearing, I suspect it's a relatively rare occurrence, though people still assert that the 6-hour clearing rule is the standard. I would not be surprised if even some NWS employees are not aware of the current guidelines (hopefully most are). It just won't die. One final thing regarding this past event. We did receive a 31.0" storm total snow report in Kinnelon (Morris County, NJ) that no doubt got at least a little attention, as it would represent, as far as I know, the largest event total in NJ from the storm. I checked in with the observer, and he confirmed that he cleared the board 3 times mid-storm to reduce the effects of compression. Unfortunately, that makes his inflated measurement invalid, at least in the context of the current guidelines (though even with the 6 hour rule, this must have been more like 1 hour clearings), so we've nixed the value. BTW, I'll personally be working on crafting a NJ snowfall map tomorrow based on hundreds of reports received. I post it here when complete. This is a good debate to have! Thanks for sharing your thoughts. * A note about Coop stations. There seems to be some confusion about what constitutes an "official" report, which is subjective in the first place. The airports are first-order stations that also double as Coop stations. The remainder of Coop sites are manned by volunteer observers, and their data also constitute "official" records in my mind, in that they make up the permanent climate record of the US and are quality controlled and archived in NOAA's NCEI GHCN-Daily dataset. For that matter, so now are CoCoRaHS data (if you are a CoCoRaHS observer, your data are a part of the weather/climate records archived at NCEI!).
  8. Not seeing it. The NAO dipped to -1 SD a couple days ago, but will be oscillating up to +1 SD for the next week or so. By December 15th, the Dec 1-15th NAO mean is likely to be near neutral, or possibly even ever so slightly positive. So far, it's not a propitious indication of an ensuing moderate to strongly negative NAO winter.
  9. Turned out much better than it seemed it would a couple weeks ago. Maples are mostly past peak here now, but still holding great color, and oaks are now peak. I think we'll see major leaf drop with the CAA event at the end of this week.
  10. Still going to end up a bit high on NYC/LGA/TTN, pretty close on PHL/EWR. Happy with the call overall.
  11. I like Hurricane Bonnie of 1998 as a potential analog. Could be a coastal NC scrape followed by fairly sharp recurve to the northeast given the synoptic scale pattern.
  12. There is also the possibility, albeit low probability, that Jose propagates sufficiently southwest such that it acts as a capture instrument, drawing Maria toward the coast. This will only occur if the mid level ridge forces Jose at or west of the east coast's longitude. Prior runs of the EC and other models had suggested that possibility. Both Jose's eventual demise and movement will be critical.
  13. Cooling degree days have been the lowest probably since 2009 for our area. I only have 766 CDD's for year thus far, quite low comparatively after the past couple summers.
  14. Agreed on all counts. Those numbers will almost certainly be too high. And yeah, definitely feeling much more fall like in terms of sun intensity now. Really noticing the lengthening nights.
  15. 16 here now. We're pretty much done given the upcoming pattern. Might be able to make the average of 18 for around here.
  16. I like where I stand with my pre-season predictions; might even end up a tad aggressive for some areas: PHL: 28 EWR: 25 NYC: 16 LGA: 19 TTN: 21
  17. 3, 5, and 7 here for May, June, and July respectively. Total 15. So far nothing in August, and it looks like nothing for awhile.
  18. 94F and day 14 for the season here.
  19. I'm tied with Newark (doubt that will last) at 12 90 degree days here.
  20. Up to 22 days here, above the normal of 17-18 I think. I had 38 in 2010. We should manage some more days in Sept.
  21. Stuck at 12 here, but I've had at least 6 days of near misses at 88-89F over the past few months. If the next two months are very warm/warm as I expect, my backyard should be able to surpass 20 days.
  22. Interior areas and urban locations already near normal for annual 90s. 20 at New Brunswick is impressive. Coastal sites like NYC still need another 7 or so. But we're really only half-way through the summer as far as the heat goes.
  23. Still stuck at 1 here (91.5 on May 28th), with 1 89F and a couple 88s as well. So far my high for June of 88 is less than May, and only 8 degrees warmer than March! Talk about a pattern reversal.
  24. I would strongly doubt that is the reason.
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