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March 12/13/14 Blizzard/Winter Storm/WWA etc


Bostonseminole
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000
NOUS41 KBOX 141250 CCA
PNSBOX
CTZ002>004-MAZ002>024-026-RIZ001>008-152000-

Public Information Statement
National Weather Service Taunton MA
827 AM EDT Wed Mar 14 2018

...BLIZZARD OF MARCH 13 2018...

Blizzard conditions were reached at many locations across
southeastern New England during the storm on March 13.

The definition of a blizzard is that falling and/or blowing snow
reduces visibility to below 1/4 mile along with sustained winds or
winds that frequently gust to 35 mph or more...and that these are
the predominant conditions for a period of 3 consecutive hours.

When reviewing whether a particular observation location had
blizzard conditions, we counted visibilities equal to 1/4 mile,
since that is quite low for an automated visibility sensor to detect.
We also made some subjective decisions. For example, at Marshfield,
MA, there were significant wind sensor outages, but mesonet data
from Duxbury Bay were used as a proxy and indicated nearly
continuous gusts at or above 35 mph during that time period.
At Martha`s Vineyard, there was a 3-hour wind data outage, but
mesonet data at Vineyard Haven indicated continuous gusts at or
above 35 mph during that period. At Plymouth, blizzard criteria was
met just before a complete data outage occurred, lasting most of the
day, which made the duration undeterminable.

The following observation sites were determined to have had a
blizzard...

HYANNIS, MA............10 Hours 35 Minutes...from 730 AM to 605 PM
MARSHFIELD, MA......... 9 Hours..............from 855 AM to 555 PM
FALMOUTH, MA........... 8 Hours 40 Minutes...from 715 AM to 1055 AM
                                        and from 1155 AM to 455 PM
MARTHA`S VINEYARD, MA.. 8 Hours 22 Minutes...from 800 AM to
                                             approximately 422 PM
BOSTON, MA..............6 Hours..............from 840 AM to 240 PM
NEWPORT, RI.............4 Hours 20 Minutes...from 850 AM to 110 PM
PLYMOUTH, MA............>2 Hours 53 Minutes from 732 AM to 1025 AM
                                             but then power outage

$$
Field
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57 minutes ago, donsutherland1 said:

An individual who, along with Eric Fisher, who were "asleep at the switch" during the storm, didn't see the prolonged/intense banding on radar that extended across Wilmington (or didn't properly understand how to read the radar) and decided to take it upon themselves to tweet to the general public questioning Ray's (40/70 Benchmark) snowfall total.

https://twitter.com/ncoramwx/status/973752308914892800

Neither of them was in Wilmington at any time during the storm. Neither of them undertook any degree of due diligence to verify the snowfall amount. They didn't even make a minimal effort. They simply and rashly  threw it out without even bothering to understand the measurement (i.e., examine the radar loops during the day, consider mesoscale effects, etc.) and went public about it. Ray deserved far better.

For all my time here at AmericanWx (and EasternWx before it), Ray has been dedicated and meticulous. He doesn't cut corners or inflate snowfall amounts.

Ray is a real asset to this Board and to the New England weather community. I very much hope he won't get discouraged by what happened yesterday.

Couldn't have said it better. Having met Ray before at the Eastern conferences and reading his posts for 10+ years now, I have zero doubt that his measurement was legit. He's as huge a weenie as any but seriously one of the best amateur mets on the entire board(along with yourself). I trust his measurement much more than any john q public report that stuck a ruler in the grass at the end of the storm and called it a day. Now if this total was coming from a certain mountain in Tolland, CT, I'd be skeptical ... ;) :P

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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!). 
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1 hour ago, dendrite said:

The thing is you have weenies like us clearing huge amounts of fluff every 6hrs and then the general public sticking the yardstick into the driveway at random times. When the PNS is showing a handful of reports a bit over 20” for the high range in a populated county and then a report comes in of over 30” it definitely stands out. That Wilmington 22.5” cocorahs report is just as fishy with about 3.00” of liquid reported. They reported 21.4”/2.75” for 7a-7a....I don’t think so. The other Wilmington cocorahs only reported 17.8”/1.22” for 7a-7a so the obs are all over the place. 

But you’re going to have trouble with people actually believing it since even the highest cocorahs reports are 20-25”. It’s simply just differing methods and that’s the nature of the beast. You’ll just have to deal with the skepticism. :lol:

We're those two day records? I had 2 /.25 before my reporting time at 6 am

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4 hours ago, donsutherland1 said:

With yesterday's 14.5"snow, March 2018 is now the 7th snowiest March on record in Boston. The most March snowfall is as follows:

1. 38.9", 1993
2. 33.0", 1916
3. 31.2", 1956
4. 22.9", 1967
5. 22.3", 1960
6. 21.9", 1906
7. 21.5", 2018

Hi Don-thanks as usual for your wonderful insight.   For the record, BOS added 0.3 after midnight so Logan is 0.1 away from 1906 and 0.5 from 1960...indeed 1.1 from 1967.  Top 3 are big mountains to climb but I think we move into 4th place without much effort.

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Just now, OceanStWx said:

If the mets are dedicated posters/lurkers on the board they know the slant stickers from the good obs. 

Some of you are so neurotic about snowfall measurements that I know you wouldn't artificially inflate your totals. 

The Lunenburg slant-sticker donated money to Eric Fishers campaign to smear Rays measurements.

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7 minutes ago, CoastalWx said:

Don't first order stations clear the board every 6 hrs?

 

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).

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2 minutes ago, Isotherm said:

 

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.

I thought OceanSt was saying many first order stations clear the board or what have you, every 6 hrs.  And what the heck defines intermediate depth measurements? every hr? every 6 hrs? 

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3 minutes ago, Isotherm said:

 

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.

Yeah there can be significant differences in max depth and regular clearing amounts. Like was mentioned in that writeup, 30" was out of line. 

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1 minute ago, CoastalWx said:

I thought OceanSt was saying many first order stations clear the board or what have you, every 6 hrs.  And what the heck defines intermediate depth measurements? every hr? every 6 hrs? 

 

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).

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2 minutes ago, Isotherm said:

 

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).

Cocorahs

Snowfall is the maximum accumulation of fresh snow during the past day prior to melting or settling.

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its interesting to come in here and see this discussion, because I'm debating snow totals with my group of friends in an IM that don't really do weather stuff... 

anyway, I'm saying that I maxed here in Ayer at my place at 14.5" and it doesn't jive with the 18 to 21" being reported around me.  Either: someone ended up in a weird nadir total; someone doesn't know how to measure snow depth; someone is lying... 

Not sure which of those, but I just measure the stack depth ... I didn't clear anything every 6 hours.  I just have a perfect snow board region that is out of the wind and it lain with 14.5" new as of midnight when I crashed, and there was no evidence of accumulation when I awoke this morning. 

So, I am left with a quandary as to how much really fell:  my 14.5" ..or, the average of 18 to 20" ... I really don't believe the latter, however.  I suppose it is possible that there was a 4 to 6" gap that shielded just my street, if not my yard...from the rest of the town...but somehow I find that less likely too - heh

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4 minutes ago, Isotherm said:

 

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).

Its also referred to in here at least a couple times: http://www.nws.noaa.gov/os/coop/reference/Snow_Measurement_Guidelines.pdf

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