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NNE Spring 2013 Thread


klw

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Pretty chilly past couple morns: 41F yesterday and 40F this morning.  Not bad for solstice time.  ;)

 

Great shots of Mt. Cardigan, hypatia--always a fun mountain to hike.

 

I'll be those wind turbines are the new ones in Groton, NH, near Plymouth.  They're up in the hills above the Polar Caves and are visible from Rt. 25 around Rumney and again in Plymouth.

 

http://www.iberdrolarenewables.us/groton.html

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I was just trying to find some records and the Tupper Lake, NY (not quite as cold as SLK, but much longer period of record) in the Adirondacks has a record low of 29F on the 19th and 26F on the 20th.  Period of record is 1899 to present.  So yeah, nothing that would threaten records I would assume given mid/upper 20s records in the Adirondack cold spots this time of year.

 

Interesting to note though that these two dates are the last two days with record lows in the 20s at that station... starting the 21st, all the records are in the lower 30s.

 

Morrisville 4S (which I think must be MVL) has a record low tomorrow morning of 36F and MPV has 40F.   The MPV record seems odd though as the record on the 19th is 33F and the 20th is 40F.  That just looks like a vulnerable day based on the surrounding records in the 30s.

 

Farmington COOP, records back thru 1893, shows 3 early summer frosts:  32 on 6/21/1918, 31 on 6/26/1979, and a truly freaky 32 on 7/8/1969.  Earliest for 1st frost is 32 on 8/22/1982.

 

No frost in my area this morning - was 1-2F milder than yesterday's 39 unless the bottom was pre-dawn.

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Pretty chilly past couple morns: 41F yesterday and 40F this morning. Not bad for solstice time. ;)

Great shots of Mt. Cardigan, hypatia--always a fun mountain to hike.

I'll be those wind turbines are the new ones in Groton, NH, near Plymouth. They're up in the hills above the Polar Caves and are visible from Rt. 25 around Rumney and again in Plymouth.

http://www.iberdrolarenewables.us/groton.html

Thanks for the link! I'm glad to know a little bit more about them. Cool stuff!

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hypatia - Cardigan looks pretty nice with all that open ledge. Hvy hvy sunburn potential :sizzle: And as freak noted, pics of beautiful NNE vistas are welcome :)

Thank you! I love seeing your hiking photos and I always look forward to your posts. You've inspired me! :)

And I hear ya about the sunburn... I made sure I had SPF 100 on my face and 50 on my arms and shoulders. I burn easily. :sizzle:

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So here's a question maybe Dendrite might know more about as he's good with temperature things..  so MVL put up a 37F ob this morning but the low is listed on the climo sheet as 38F.  The min temp map also shows 38F. 

 

Does this have to do with rounding or something given the METARS are in Celsius?  I just found it curious that there's a 37/37 observation and the overnight low was 38F. 

 

Same thing with SLK... several 30F observations with varying degrees of fog, yet the low is listed as 31F?  Anyway, SLK was the coldest temp east of the Rockies this morning, which really isn't all that uncommon.

 

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Such as how does this list of observations end up with an overnight low of only 31F and not 30F?

 

attachicon.gifSLK.jpg

We noticed that as well. However upon further checking, when it did touch 30F when the SPECI went out, it apparently did not hold at 30F for a five minute average. So while it says 30F at 4:38AM, the assumption is on the 5-minute obs (4:40AM, 4:45AM) the 5-minute average was still 31F.

 

Something like this:

4:36- 31

4:37- 30

4:38- 30

4:39- 31

4:40- 31

 

Would still give you the 5 minute average of 31F for the observation.

 

It appears that this occurred much of the time between 4:30AM-5:30AM but never holding at 30F long enough to make the 5-minute average 30F.

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We noticed that as well. However upon further checking, when it did touch 30F when the SPECI went out, it apparently did not hold at 30F for a five minute average.

 

Very interesting... I could see that for the one MVL ob of 37F, but does seem odd given that there's 5 of them at SLK that had 30/30F. 

 

Or when a new METAR is sent out with a changed visibility (appears that's the reason for the multiple obs) does it not update the temperature, too?

 

I do see that the normal, hourly update came out at 31F though.

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Very interesting... I could see that for the one MVL ob of 37F, but does seem odd given that there's 5 of them at SLK that had 30/30F. 

 

Or when a new METAR is sent out with a changed visibility (appears that's the reason for the multiple obs) does it not update the temperature, too?

 

I do see that the normal, hourly update came out at 31F though.

Not sure if you saw the added part to my post, so I'll repost it again.

 

 

 

We noticed that as well. However upon further checking, when it did touch 30F when the SPECI went out, it apparently did not hold at 30F for a five minute average. So while it says 30F at 4:38AM, the assumption is on the 5-minute obs (4:40AM, 4:45AM) the 5-minute average was still 31F.

 

Something like this:

4:36- 31

4:37- 30

4:38- 30

4:39- 31

4:40- 31

 

Would still give you the 5 minute average of 31F for the observation.

 

It appears that this occurred much of the time between 4:30AM-5:30AM but never holding at 30F long enough to make the 5-minute average 30F.

 

 

 

But yeah it does seem quite odd that each SPECI went out at one of the minutes it happened to be 30F.

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Such as how does this list of observations end up with an overnight low of only 31F and not 30F?

 

attachicon.gifSLK.jpg

The SPECI's are only in whole degrees C. That's why you get a jump from 30F in the SPECI's to 31F at the hourly METAR, and back down to 30F in the SPECI's again. So the automated METAR decoding sites are converting -1C to 30F when the actual temp was actually 31F (-0.6C). They should just add the T group in all of the SPECI obs since this kind of thing happens a lot. I think the SPECI's report the 5min running avg the same as the hourly METARs do.

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The SPECI's are only in whole degrees C. That's why you get a jump from 30F in the SPECI's to 31F at the hourly METAR, and back down to 30F in the SPECI's again. So the automated METAR decoding sites are converting -1C to 30F when the actual temp was actually 31F (-0.6C). They should just add the T group in all of the SPECI obs since this kind of thing happens a lot. I think the SPECI's report the 5min running avg the same as the hourly METARs do.

Could be that too.

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Could be that too.

 

 

The SPECI's are only in whole degrees C. That's why you get a jump from 30F in the SPECI's to 31F at the hourly METAR, and back down to 30F in the SPECI's again. So the automated METAR decoding sites are converting -1C to 30F when the actual temp was actually 31F (-0.6C). They should just add the T group in all of the SPECI obs since this kind of thing happens a lot. I think the SPECI's report the 5min running avg the same as the hourly METARs do.

 

 

And yes, the same thing happened with MVL. 37F (2.8C) and 38F (3.3C) both would be reported as +3C in a SPECI, but when that 3C gets converted back to degF the result is 37.4F which rounds to 37F.

 

Didn't even cross my mind that it could be as simple as that. I even went back through and checked each SPECI directly though the ASOS. Each 5 minute average was 31F or higher.

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Ahhh that makes a ton of sense now.  Thanks for the clarification Dendrite and Nittany. 

 

I thought I had heard issues like this with rounding of Celsius to Fahrenheit...  and makes sense why the SPECI obs were all the same 30F while the normal hourly one was 31F.  Same with MVL with the 4:54am ob being 38F, then the SPECI came out 3 minutes later rounding down and causing the 37F.

 

Great info.

 

So one would then assume that basing temperature assumptions off SPECI can be sort of dangerous as its not nearly as exact as the hourly?

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Didn't even cross my mind that it could be as simple as that. I even went back through and checked each SPECI directly though the ASOS. Each 5 minute average was 31F or higher.

 

So the temp may have never even been 30F, even for a minute or two,... as the 30F SPECI is just due to a rounding issue and only reporting whole degrees C.  That's what I'm hearing then?

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So the temp may have never even been 30F, even for a minute or two,... as the 30F SPECI is just due to a rounding issue and only reporting whole degrees C.  That's what I'm hearing then?

If it was 30F it would have made it in the 12z 6hrly max/min grouping and it didn't.

 

METAR KSLK 201151Z AUTO 00000KT 10SM SCT001 09/08 A3025 RMK AO2 SLP247 T00890078 10089 21006 51011

 

That's a low of -0.6C or 31F.

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So the temp may have never even been 30F, even for a minute or two,... as the 30F SPECI is just due to a rounding issue and only reporting whole degrees C.  That's what I'm hearing then?

Well it may have been 30F for a minute or two, but it needs to be for 3 minutes of the 5 minute running average in order to register.

 

So in official terms, yeah its a rounding error.

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The raw, unaveraged 1-minute data is available on NCDC somewhere. Of course that isn't "official" since the 5min running mean is used for official 1-minute temps. There can be some big swings in the raw numbers though.

 

That's something I also didn't know... that the highs and lows are 5 minute averages.  It makes sense but I just hadn't really considered it.  I previously thought time didn't factor into it...and it was just the highest/lowest reading of the day, even if only for 1-minute. 

 

Always fun to learn something.  Again, thanks for the explanation Dendrite and Nittany.  I posted it to BTV's facebook prior to here, so sorry Nittany if you had to repeat the answer there as well.

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I love how the last trace of sunlight along the horizon doesn't fade out until about 10:05

I note that too Scott. Interestingly I am posting this right now from SW Conn. (Danbury on the NY line). I am driving to Baltimore for the weekend. I noticed that although I am further west it was totally dark by 9:45pm this evening. On the first day of summer daylight really increases as you move straight north it seems!

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