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June 2017 Observations & Discussions Thread


bluewave

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6 minutes ago, bluewave said:

This paper describes how they do it.

https://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/documentation/temperature-methodology.pdf

This report describes the methodology used to compute daily, monthly, seasonal, and annual normals for numerous temperature-related variables at about 7,500 weather stations for the 1981-2010 Normals period. A climate normal is typically defined as a 30-year average of an atmospheric quantity, such as maximum temperature. However, advanced statistical techniques are used to account for missing data values, inhomogeneities, station moves, etc. and therefore the normals presented here are much more than 30-year averages. This report offers a preliminary description of all procedures used to compute the new normals for temperature-related variables. We intend to submit a journal article on this matter which, if and when accepted, would replace this report as the authoritative reference for the computations done on temperature-related variables for the 1981-2010 Normals. For information regarding precipitation-related normals or hourly normals (including hourly temperature normals), please review the accompanying documentation.

As described by Menne and Williams (2009) and Menne et al. (2009), NCDC provides monthly temperature data values that have undergone robust quality control and standardization at the monthly timescale. For the 1981-2010 Normals, the approaches described in these papers were applied to monthly maximum and minimum temperature values that were in turn computed from GHCN-Daily values. Monthly values were computed for station-months for which no more than nine missing or suspect daily values were present in GHCN-Daily. The standardization procedures account for both documented and undocumented station moves and other changes in observing practices. Therefore, we give precedence to normals computed from monthly temperature data.

raw numbers should be compared to raw numbers...Not smoothed numbers...

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24 minutes ago, bluewave said:

Not if the raw numbers are corrected for errors. Not sure what you mean by smoothed.

fa martin called it smoothing the numbers...I take my numbers from the national weather service or ncdc (thanks for the link)...the monthly and annual page for NYC are raw numbers?...the monthly climate from the ncdc are raw also?...where are the errors that were fixed and are they figured into the monthly average temp they post on their sight?...

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Just now, uncle W said:

fa martin called it smoothing the numbers...I take my numbers from the national weather service or ncdc (thanks for the link)...the monthly and annual page for NYC are raw numbers?...the monthly climate from the ncdc are raw also?...where are the errors that were fixed and are they figured into the monthly average temp they post on their sight?...

That's a good question. I don't think the NWS homepage reflects any changes that the NCDC might make after the fact for quality control. Even NASA GISS has raw temperature plots for NYC that get revised in later versions.

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18 minutes ago, bluewave said:

That's a good question. I don't think the NWS homepage reflects any changes that the NCDC might make after the fact for quality control. Even NASA GISS has raw temperature plots for NYC that get revised in later versions.

my only beef is we are comparing what the June average is for a certain place and then compare it to a smoothed number...I looked up Newark's climate reports for all the Junes since 1981...I took the average that was there for each year...after the math it came to an average of 73.0...Now noaa has a June mean in its climate page of 72.4...That's a big difference...

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49 minutes ago, uncle W said:

my only beef is we are comparing what the June average is for a certain place and then compare it to a smoothed number...I looked up Newark's climate reports for all the Junes since 1981...I took the average that was there for each year...after the math it came to an average of 73.0...Now noaa has a June mean in its climate page of 72.4...That's a big difference...

Yeah, but those monthly climate reports may have been amended by the NCDC so the actual corrected average is 72.4. Remember during that 30 year period new ASOS units were installed.

https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/climate-normals/1981-2010-normals-data

Automated Surface Observing System (ASOS) stations were implemented in the mid-1990s. As a result, there are inhomogeneities in the 1981–2010 underlying data records due to changes in observing practices. These inhomogeneities are accounted for to the extent possible by quality control and the standardization of monthly temperature values. See Menne et al. (2009) and Menne and Williams (2009) for more information.

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Marginal severe threat today especially northern parts of the area with great lapse rates.

 

 ...Eastern New York/Southern New England...
   An upper-level trough will move across the lower Great Lakes and
   Mid-Atlantic today. At the surface, a cold front will advance
   eastward across the Northeast. Ahead of the front, a narrow corridor
   of maximized low-level moisture is forecast to set up across western
   parts of southern New England this afternoon where surface dewpoints
   should be in the 50s F. This will allow a corridor of instability to
   develop around midday with thunderstorms initiating along the front.
   This convection is forecast to move eastward across southern New
   England this afternoon. Forecast soundings at 21Z in southern New
   England show 0-6 km shear around 45 kt with steep low to mid-level
   lapse rates. This may be enough for storm rotation within the
   stronger cells. Hail and strong wind gusts will be the primary
   threats.

SND.thumb.png.94aac0aa9674b20c666204404eaf9482.png

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36 minutes ago, gravitylover said:

Looks like another line of wetness is on the way.  Bummer...  We can't seem to go more than 36 hours at a time without rain, it's getting tiresome :unsure:

That line is decaying pretty quickly... probably won't be much left of it when it reaches us. I'm not too sold on storm coverage later so maybe most of us can stay dry for the balance of the day.

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2 hours ago, Cfa said:

Nasty accident involving two trucks on the LIE. Always a crash in the rain.

Rainy days always pissed me off.  The traffic was always worse because you'd get a bunch of people who normally walk to the LIRR or walk to the bus stop, maybe they live a 1/2 mile or mile from the station or stop.  On rainy days though they'd all drive instead and you end up with 10-20% more cars.  

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17 minutes ago, bkviking said:

Thunderstorms just North or Port Jefferson. Had great outflow wind blast here. Beautiful 

IMG_4738.PNG

For a time I could see the t storm moving near Stamford CT and over the Sound.  Big billow clouds just ENE. 

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Looks like a cool night is on the way for the Northwest burbs.  My forecast low is 54°

From Mt. Holly:

Quote

Thereafter, large-scale descent should begin in earnest, with skies rapidly clearing out and the low levels drying out through the rest of the night. With relatively light winds, temperatures should fall well below average overnight. Lows are forecast to be near 50 in the Poconos and near 60 on the coast and in the urban corridor.

 

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Updated thoughts from Mt. Holly:

Quote

Skies are already starting to clear out and we should see some drying occur as a more westerly flow is in place overnight.  Some low level moisture may linger a bit in areas where rain fell through this evening, and some light patchy fog might develop towards daybreak.

Light winds overnight combined with the clearing skies will allow for good radiational cooling to take place. Already starting to see some indication of this with 9pm temperatures already falling in Millville (65) and Somerville (63) and Andover (61).

 

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