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bluewave

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  1. 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.
  2. 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.
  3. 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.
  4. Yeah, there have been several events like that. I believe it was last summer or the one before that that big 5"+ dump fell over the Sound and brushed the North Fork.
  5. IMHO the 2005-2007 period pretty much reset the whole Arctic background state. Arctic amplification really took off at that time when the September avg extents started regularly falling below 6 million sq km on NSIDC. We didn't even need a 2012 record minimum the last few years to set the extreme Arctic warmth records.
  6. Not if the raw numbers are corrected for errors. You can probably write the NCDC and ask them directly.
  7. 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.
  8. The NCDC sets the 30 year average after they correct for any bad data in the raw numbers. That's why the 30 year means might not be an exact average of the 30 years of raw numbers.
  9. NOAA adjusts the raw 30 year means to take out any errors.
  10. We would need a solid dipole pattern to lock in to have a chance of challenging 2012. Otherwise, it's going to be another year that the 2012 record holds. Seems like the really extreme Arctic conditions for the most part since 2012 have been during the winters instead of the summers from 2007-2012.
  11. The current +0.8 at Newark is in line with June having the least top 10 warmth of the summer during the 2010's. Newark top 10 warmest months on record during the 2010's: Jun...2010...#2....2011....#10 Jul....2011...#1....2010....#3....2013...#5....2012...#6.....2016....#10 Aug..2016...#2....2015...#7.....2010...#10
  12. The highest average temperature at LGA is between July 13-28. But the record highest temperature for each of the local stations is between 7/3 and 7/22. EWR....7-22-11...108....NYC....7-9-36...106....LGA....7-3-66....107....JFK....7-3-66...104...BDR...7-22-11....103...ISP....7-3-66...104
  13. If this cooler pattern continues, then it might not really matter if we know the exact volume for sure. 2012 and 2011 weren't all that different on volume in August and September. But the 2012 record warmth with the weather pattern made all the difference between the two extent finishes in September. This June is continuing the post 2012 stronger polar vortex pattern vs the 2007-2012 raging dipole regime. We would need a July 2015 rapid reversal to really accelerate the melt. But that kind of reversal isn't showing up in the longer range guidance as of yet. Even Greenland is enjoying a below average melt compared to recent years.
  14. PIOMAS actually pulled back closer to the pack the last few weeks.
  15. Yeah, we look to continue the theme of most weekends since mid-April featuring at least some measurable rainfall.