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Showing content with the highest reputation since 12/25/2019 in all areas

  1. 10 points
  2. 7 points
    850s below freezing will always produce snow during the day in early March despite above freezing surface temps. Always use snow maps with the most questionable of p-type algorithms so long as it yields more snow. Say a forecast caved by pointing to another forecast. Ignore warmer temps or lower qpf shown on short-term models if they wreck your final call made the night before a storm. If the Euro is the only model showing snow, justify a snow forecast because even in 2020 "Euro is the king".
  3. 7 points
    Downpouring sleet and freezing rain in Towamencin. Never got enough snow to cover the grass tips, but it was slick enough for the kids to go sledding and have fun. My husband's ballcap was covered in a glaze of ice.
  4. 7 points
    Got about 2.5” or so. Looks beautiful out there.
  5. 5 points
    You don't want to be in the jackpot zone 5 days before
  6. 5 points
    Merry Christmas to all my fellow weather geeks! Here’s to a snowy winter!
  7. 4 points
  8. 4 points
    Ended up with 0.3" of snow from the snow squall that blew through temp dropped to 30 with it's passage
  9. 4 points
    NOAA replied with the below feedback: -------------------------------------------------------------- Hi William, Our GHCN-Daily POC Matt Menne has provided the following feedback in italics to your questions regarding Neshaminy Falls, PA's and other stations' data values and GHCN-Daily's QC of them: ************************************** ************************************** "Please see my responses to the questions below (in italics): 1. Did NOAA really run a spatial consistency test on the TMIN value on October 2 for Neshaminy Falls? Yes, the checks are run daily on all data automatically. As long as the minimum data requirements are met for a QC test, the test is applied a) If the answer is no, why not? 2. If a spatial consistency test was done and it passed QA does this mean regardless of the fact the value had a difference from nearby weather stations that exceeded 8 degrees Celsius is this due to the way the math behind the spatial consistency tests (both regression and corroboration) are structured? As noted in Durre et al. 2010, (Table 4), the absolute value of the residual for the spatial regression check needs to exceed 8 deg C and the normalized residual must exceed 4.0 standard deviations using neighboring values for the day before, the day of and the day after the value being tested in order to fail the test. Likewise the spatial collaration test compares anomalies on the day before, the day of and the day after the value in question and the anomalies must differ by 10 deg C. If these conditions are not met, the value will pass the test. a) In light of the examples above would it make sense to modify the math behind the spatial consistency tests? The spatial checks are conservative by design to avoid flagging valid observations. Altering the thresholds would inevitably lead to an increase in legitimate values failing the checks. While we would like to catch only errors, the nature of these observations is such that no set of checks can be assured to flag only errors. The spatial consistency checks are particularly susceptible to flagging too many legitimate values, which is why the thresholds are set to be conservative. 3. Why did the July 11 example from South Jersey Regional airport fail the spatial consistency test yet the similar October 2 example from Neshaminy Falls did not? It is all a question of exceeding or not exceeding the thresholds described in Durre et a. 2010 (Table 4), assuming the criteria for having the minimum number of neighboring observations are met. 4. Do you think since the eastern United States had hot 90 degree plus Fahrenheit afternoon temperatures on October 2 that somehow that TMIN of 52 by Neshaminy Falls should have been caught by some test since it so "obviously" wrong? We would certainly like to flag all errors, however the observational day for COOP observers is sometimes somewhat irregular if the observer is unable to read the thermometers at exactly the same time each day. This is why many of the daily quality checks consider a 3-day window centered on the day in question. Note in this example, that a front was nearby separating the very warm air in the mid-Atlantic from a cooler air mass in New England, and that much cooler temperatures followed on Oct. 3, which was likely a factor in the value passing the spatial check. In a case like this, NOAA's Datzilla process can be used to flag a value based on additional scrutiny and forensics. 5. Furthermore, not counting the unarchived November 1 TMAX of 73 and the December 11 TMIN of 15 for Neshaminy Falls that are obviously wrong I have 2 other recent archived examples from Neshaminy Falls. September 15 TMIN of 54 Fahrenheit (not sure about this one since it did rain). October 1 TMIN of 53 degrees Fahrenheit (that is obviously wrong for the same reasons stated above for October 2). For September 15 and October 1 for Neshaminy Falls the difference from the 2 nearby Trenton Mercer airport and South Jersey Regional airport weather stations was only 7-9 degrees Fahrenheit. Would it make "prudent" sense to make the test threshold even tighter or will this lead to more false positives/more workload/not feasible with budget constraints/etc. ? Based on extensive testing and years of user feedback, we have opted for the thresholds in place that prevent over-flagging the data but require the occasional need to submit a "Datzilla" data ticket to requiring us to flag or unflag a particular value. 6. Also in regards to (4) note as stated there were two days in a row (October 1 and October 2) that the TMIN values were obviously wrong for Neshaminy Falls yet that was not enough to cause either the spatial regression or the spatial corroboration check tests to fail for at least one of those days? As the response noted for the first question (3), is all a question of exceeding or not exceeding the thresholds described in Durre et a. 2010 (Table 4), assuming the criteria for having the minimum number of neighboring observations are met. 7. Finally note for South Jersey Regional airport the inaccurate TMIN of 28 degrees Fahrenheit on September 27 appropriately failed the spatial consistency test. (Neshaminy Falls and Trenton Mercer airport were 47 degrees and 50 degrees Fahrenheit respectively). However the South Jersey Regional airport inaccurate TMAX of 94 degrees Fahrenheit on July 23, 2019 DID NOT fail the spatial consistency test. It is an inaccurate value -- Neshaminy Falls And Trenton Mercer airport reported respectively 76 and 75 degrees Fahrenheit on that day (and thus the difference is at least 10 degrees Celsius for both cases). Notice too no hourly temperature values were reported for that entire day for this ASOS station so there must have been some issue going on: https://www7.ncdc.noaa.gov/CDO/cdoselect.cmd Regardless, since a TMAX of 94 was submitted why did it not fail the spatial consistency test? Again, it is all a question of exceeding or not exceeding the thresholds described in Durre et a. 2010 (Table 4), assuming the criteria for having the minimum number of neighboring observations are met. ************************************** ************************************** In Matt's reply to your Question #4 and #5, he has mentioned that we (NCEI) have the ability to flag (or unflag if it applies) a data value; doing so has to be based on supporting evidence to do so. For more recent data values such as these for the past data-year of 2019, we very much depend on the National Weather Service (NWS) and its Forecast Office at NWS-Mt. Holly, NJ (WFO-PHI) to inform us via the proper channels of whether these actions are necessary. We're going to depend on their expertise in the case of these stations' questioned data temperature values to do so, if needed. We (NCEI) very much depend on NWS to verify and properly document via Station-Level Metadata Updates that the equipment and observing practices at each station meets the standards of the well established NWS Directives pertaining to the data observing network in question (COOP, ASOS, etc.). Having said that, overall issues with the data observing practices with the COOP Site at Neshaminy Falls, PA (GHCND ID: USC00366194; COOP ID #366194) and the other stations in this general local area that you've mentioned here should be further discussed with NWS-Mount Holly, NJ (WFO-PHI) and NWS Eastern Region HQ all of whom are cc'd on this email reply. I hope Matt's answers to your questions and our further advisement help your understanding of GHCN-Daily's QC of NCEI's archived data. We greatly appreciate your email inquiry and have a great day! Best Regards, Bryant Korzeniewski
  10. 4 points
    Merry Christmas and Happy Hanukkah everyone!
  11. 3 points
  12. 3 points
    Self-proclaimed chief weather weenie of the PhillyWx board, SusquYawn, is desperately clinging to hope for frozen precip somewhere in our forum area this weekend. In the midst of a developing atrocious mid-winter pattern, a perfect alignment of weather patterns could lead to a redeveloping, slow moving coastal. As of now, SusquYawn proclaims a 2.8% chance of snow at PHL this weekend. Stay tuned for irrational hope, highlighting the 1 ensemble member of each guidance suite showing frozen, and fluctuating odds between 0-5%. I need a new hobby.
  13. 3 points
    2” of snow topped by IP then freezing rain is fine by me with LP in the Lakes setup and Barney on the way. I just need it white. Cold and brown is the WORST
  14. 3 points
  15. 3 points
  16. 3 points
    Something to also point out, which will help with snow accumulation. Strongest lift right in the DGZ so nice fatties falling
  17. 3 points
    Thank goodness my daughter woke me up st 1145!!
  18. 3 points
    Merry Christmas!!! Hopefully Things turn around come January!
  19. 2 points
  20. 2 points
    The media refers to these as "bombs" now or frankenstorms.
  21. 2 points
    I'd say just shadow heisy, probably could get atleast 10 weenie outputs
  22. 2 points
  23. 2 points
  24. 2 points
    YES! A perfect exercise to distract the morose forum members for the next 2 weeks while we await the promised land! I will most assuredly dig into this in the coming days and look forward to other comments
  25. 2 points
    Yeah, I don’t buy the GEFS cold pattern around the 5th with the vortex and -pna. But the eps and Geps look good (fingers crossed) We even see the central Canada ridge move towards Greenland.
  26. 2 points
    What’s funny is it hasn’t be one dominant pattern that has screwed us. It’s been a combination of a few different things that has worked against us. I’m all set with a weak nino enso state. I would love to roll the dice on something else please lol
  27. 2 points
    FWIW for those who follow the rmm plots, the bringing out into phase 5 is them jumping on a kelvin wave that froms in 5 then quickly moves through 6-7 and into 8. Main forcing though is in phase 8 with another wave gaining traction in phase 2
  28. 2 points
    We have a long shared driveway that drops 50'...encased in ice. Had to park up top and walk down. My son wiped out, epic fail on his part lol. Trees glazed, wish I could see it during daylight but probably will melt. 31.8. The burst of snow before sleet was awesome. The hours of freezing rain came as a surprise. Thought the column would be cold enough for sleet but that only lasted about 1 hour.
  29. 2 points
    Just scraped about 3/8" of sleet off the driveway. It was a LOT easier to shovel the snow earlier. Time for a nice Woodford Reserve old fashioned, no measuring of course, sit back and watch some TV.
  30. 2 points
    I've seen a few papers papers in the past month or two that indicate the pattern is key vs SST or sea ice. Of course that begs the question of what did cause the pattern to form and persist.
  31. 2 points
    One thing with the cfs though, look at it's mjo forecast, doesn't have the sling back to phase 6 it plows into phase 8. Granted the cfs mjo forecast makes more sense to me cause that where the main forcing is. But thats why it's pretty colder than everything right now
  32. 2 points
    From an event perspective, yeah I was telling co workers last Saturday. For details, I’d go to a different supermarket.
  33. 2 points
    Your main concern should be how much precip. falls. If it’s ~0.40” liquid and a snow/sleet mix then you’re destined for 2-4”, probably. I think south of 78, anyone seeing over 3” would be a miracle with this event (and winter).
  34. 2 points
    Was that post during my backswing??? I would just say the GFS 2M temps are not very good.
  35. 2 points
    System won't be onshore till tomorrow eve, could get a bit better or worse. Southern edge is most sensitive to small changes.
  36. 2 points
    Lets see what the ENS do - less interested in the OP member If the ENS shift south that's encouraging
  37. 2 points
    Improving snow odds - I95 in the light green 12 hours ago
  38. 2 points
    Dr. NO for at least one run says yes.
  39. 2 points
  40. 2 points
    KU snow storms - 1/20-21/78, 2/4-5/95, 1/19-20/61 Would have been KU (after book came out) - 2/10-11/07
  41. 2 points
    Yep, 1032 @tombo82685 high waiting for it. Ends up redeveloping and slams sne. It’s quicker then the gfs but definitely a trend colder before the storm
  42. 2 points
    As far as stormy goes, snow wise, it’s bland the next 7-10 days, but individuals say things pic back up if the eps are handling the H5 pattern correctly. through day 10 almost , the mean is atrocious. But then it gets better: and then, finally the indies:
  43. 2 points
    Very similar to the 2 previous snow "events". Collected 0.13"
  44. 2 points
    welp, think only one thing left to do at this point
  45. 2 points
    TT's near 50 with a squall line on the HRRR...guidance for past 3 days has been more aggressive than normal keeping the squalls intact farther SE than normal. We'll see...
  46. 2 points
  47. 2 points
    EPS kind of held firm last night, didn't get better but didn't get worse. Truly think if we are going to shift towards a better pattern it's going to be towards or after the 20th. Till then....
  48. 2 points
    You too bud, lets hope for a better Jan!
  49. 1 point
    I see nothing wrong with either of those looks. That actually looks damn good. You have pna ridge split flow and active southern stream there.
  50. 1 point
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