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NNE Spring


mreaves

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So just using another example, the F6's list Saint Johnsbury's ASOS May temperature of 55.4F, or -0.9F below the normal of the COOP Site.

 

But in reality, it was really +0.8F above the normal of 56.3F because the COOP site came in with 57.1F.

 

More comparative now with the rest of the May numbers from around the state:

 

BTV: +2.6

MVL: +1.6F

ST. J: +0.8F

MPV: +0.4F

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You can access both the Saint Johnsbury and Saint Johnsbury ASOS data sets on NCDC (just type in Saint Johnsbury in the search, and they should both come up).

 

But again just showing the big differences that exist:

 

COOP/ASOS

Jan- 16.9/15.3

Feb- 17.8/16.3

Mar- 21.2/19.0

 

And they use the COOP site for normals.

 

Now it takes NCDC a few months to continually update the data, so the Saint Johnsbury (non-ASOS) automatically defaults to Saint Johnsbury ASOS, until they go in and correctly certify it. So on the site its showing April and May as identical, but I'm looking at hard data from the COOP site, and can assure you they are very different as I mentioned for May. Within a couple of months, that will change on the NCDC site as well.

 

 

 

Lol @ the whole thing, but I hope my explanation makes a little sense, even though the process doesn't.

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So just using another example, the F6's list Saint Johnsbury's ASOS May temperature of 55.4F, or -0.9F below the normal of the COOP Site.

But in reality, it was really +0.8F above the normal of 56.3F because the COOP site came in with 57.1F.

More comparative now with the rest of the May numbers from around the state:

BTV: +2.6

MVL: +1.6F

ST. J: +0.8F

MPV: +0.4F

Ah ha! Great posts dude and yes that helps. You're talking about a nearly 2F increase in departures from the May data...and fits much more evenly.

That makes a ton of sense now. They are using the 4pm-4pm normals and comparing them to midnight-midnight data which is colder. You figured it out, haha. So for one, the climate isn't the same as BTV, but since they use a 4pm cut-off, the normals are biased warm.

I still have a minor questioning of the MVL vs MPV as I firmly believe MPV should average 1-2F colder than MVL, but that's not as big of a deal...there are days like today where MVL goes 67/39 and MPV is 66/40 so it's the same. Do you know if they switched sites at MPV? Like MPV used to be down at 700ft near the actual city, instead of up at almost 1200ft at the airstrip? Or has it always been up at a higher elevation?

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Ah ha! Great posts dude and yes that helps. You're talking about a nearly 2F increase in departures from the May data...and fits much more evenly.

That makes a ton of sense now. They are using the 4pm-4pm normals and comparing them to midnight-midnight data which is colder. You figured it out, haha. So for one, the climate isn't the same as BTV, but since they use a 4pm cut-off, the normals are biased warm.

I still have a minor questioning of the MVL vs MPV as I firmly believe MPV should average 1-2F colder than MVL, but that's not as big of a deal...there are days like today where MVL goes 67/39 and MPV is 66/40 so it's the same. Do you know if they switched sites at MPV? Like MPV used to be down at 700ft near the actual city, instead of up at almost 1200ft at the airstrip? Or has it always been up at a higher elevation?

 

Correct haha.

 

As far as MVL versus MPV, I did some digging and it looks like MVL may be the problem site as it was relocated twice, and has actually not even been around for the full 30 year normal period (so I don't know how we even have normals?) lol. Hence why we don't use that as an official climate site.

 

According to NCDC, from 1986-1987 it was operational as a COOP site in a location 2.3 miles northeast of its current location (it was at the Post Office), then shifted to 40 feet from its current location in 1987 at the site of the future airport and operated until 1990. It was then taken out of commission between 1990 and 1995, and reinstated at the newly built airport at its current location in 1995, with the site slightly shifted by 40 feet (elevation remained consistent).

 

So a few things could be shady with respect to the normals there... the siting changed, and its not a full 30 year normal.

 

 

However all is not perfect at MPV either, but does look better. In the normals period (1980-2010), the elevation started at 1126 feet when it was a COOP site and then was moved to 1165 feet in 1993 when they added an ASOS, so about 40 feet in elevation change.

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