nw baltimore wx Posted August 11, 2015 Share Posted August 11, 2015 Nice article by Jason S. in Washington Post about it. I have been on this for decades with little to no support until a while ago when a former state chief met got involved. It cast me a friendship but the head in the sand had to stop. Looks like at least 2 degrees during the day and sometimes up to 4 and no night values but those generally run 4 to in some more extreme radiational events 10 degrees. The idea that a small patch of earth where the sensors are could overcome tons of atmosphere, winds, snow cover, rain, was always weak. Some of the really nasty detractors and disclaimers can begin thier mea culpas right now. I'd like to see how it plays out over the next few months and even longer. But I'm glad that you feel somewhat vindicated. Link to comment Share on other sites More sharing options...
MN Transplant Posted August 11, 2015 Share Posted August 11, 2015 Nice article by Jason S. in Washington Post about it. I have been on this for decades with little to no support until a while ago when a former state chief met got involved. It cast me a friendship but the head in the sand had to stop. Looks like at least 2 degrees during the day and sometimes up to 4 and no night values but those generally run 4 to in some more extreme radiational events 10 degrees. The idea that a small patch of earth where the sensors are could overcome tons of atmosphere, winds, snow cover, rain, was always weak. Some of the really nasty detractors and disclaimers can begin thier mea culpas right now. The problem with declaring victory here is that there is no indication that the equipment has been inaccurate for "decades". DCA simply by geography should be warmer than most places, and the built environment makes it even warmer. That's the way it is. It has only been quite recently that it has been anomalously warm and that's why they swapped out the sensor. Link to comment Share on other sites More sharing options...
WEATHER53 Posted August 11, 2015 Share Posted August 11, 2015 The problem with declaring victory here is that there is no indication that the equipment has been inaccurate for "decades". DCA simply by geography should be warmer than most places, and the built environment makes it even warmer. That's the way it is. It has only been quite recently that it has been anomalously warm and that's why they swapped out the sensor. They fixed something that they had been loath to acknowledge even existed. There is equally no indication that the equipment has not been inaccurate for decades. You could see the correction in effect today as DCA/IAD/BWI on westerly breezes were all within 3 degrees of each other, DCA tops at 87 at the observed time of 2pm. 2 days ago it would have registered 90. It may still be erred as the site appears to be an old macadam surface that was left to deteoriate and now is mostly grass growing up through the old debilitated surface. In light of the parties referenced in the article is is surpising that you were unable to divorce yourself from "All is Ok at DCA" Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted August 11, 2015 Share Posted August 11, 2015 DCA is back up to 88F now. I don't think this is going to make a huge difference. Link to comment Share on other sites More sharing options...
Ian Posted August 11, 2015 Share Posted August 11, 2015 They fixed something that they had been loath to acknowledge even existed. There is equally no indication that the equipment has not been inaccurate for decades. You could see the correction in effect today as DCA/IAD/BWI on westerly breezes were all within 3 degrees of each other, DCA tops at 87 at the observed time of 2pm. 2 days ago it would have registered 90. It may still be erred as the site appears to be an old macadam surface that was left to deteoriate and now is mostly grass growing up through the old debilitated surface. In light of the parties referenced in the article is is surpising that you were unable to divorce yourself from "All is Ok at DCA" Did you even read the article? On June 9 the sensor was half a degree off from the test equipment. After two days of temps not sure we know anything for sure other than it was replaced. It does seem like its a little closer aligned to wxbug temps today though for the most part it has been in the past. There have been a handful of odd days in recent times... Link to comment Share on other sites More sharing options...
Inverted_Trough Posted August 11, 2015 Author Share Posted August 11, 2015 Today's highs: IAD: 89 BWI: 89 DCA: 90 How about that!? DCA was within one degree of the other airports today. That has been a VERY rare occurrence this summer. We'll need a lot bigger sample size, of course, but hopefully the new sensor corrects the divergence that was the original topic of the thread. Link to comment Share on other sites More sharing options...
WEATHER53 Posted August 12, 2015 Share Posted August 12, 2015 Today's highs: IAD: 89 BWI: 89 DCA: 90 How about that!? DCA was within one degree of the other airports today. That has been a VERY rare occurrence this summer. We'll need a lot bigger sample size, of course, but hopefully the new sensor corrects the divergence that was the original topic of the thread. The effect was immediate. Vindication for me with intense push back from parties regarding this for years in several venues. There is more to the bent fins than has been reported. Sorry some found it necessary to muck up the other thread but for those of you who totally trashed me year after year about this I would now accept your mea culpas. Link to comment Share on other sites More sharing options...
Inverted_Trough Posted August 13, 2015 Author Share Posted August 13, 2015 Today's highs: IAD: 84 BWI: 85 DCA: 85 Two days in a row with very close agreement. Seems like the effect was significant - the next few months of data should quantify how much of an effect this had. Unfortunately, I'm now convinced that the count of 90-degree days at DCA for this summer is complete garbage. I don't know what the number truly should be - nobody does - but it's clearly not 39. Whatever we end up with at the end of this summer should have an asterisk next to it. Link to comment Share on other sites More sharing options...
Ian Posted August 13, 2015 Share Posted August 13, 2015 Both the last two days were the type that should give the area fairly uniform readings. It will be interesting to see going forward as we gather more data points. Howard should name names as he is being too indirect to know who he wants apologies from. I think plenty of us have questioned DCA at one time or another. Others also understand that things like UHI are real etc. I still have enough data points to believe that it hasn't been way off forever and the reading having it off this week may have just been a random snapshot toward the more extreme end. Databases as a whole are awful when it comes to specificity. It's usually more about subtle trend lines over time and the like. Little doubt a whole lot of weather stations are reporting bad readings at one time or another IMO. The whole subject is rather soft and it's one of the more concrete areas of weather records. I agree it does call into question the number of 90-degree days.. perhaps the May record.. etc. Though again we have a June datapoint where the temp was very close and within a rounding error. So.. hard to say a lot I suppose. Arboretum is rather close.. PHL has like 25. I doubt it's the Dulles number heh. Link to comment Share on other sites More sharing options...
CAPE Posted August 13, 2015 Share Posted August 13, 2015 Heard the on-air met with WTOP today say that the DCA temp sensor was recalibrated over the weekend. Can anyone confirm? Wonder what they calibrated? I would assume the sensor type is a platinum RTD. The sensor itself can be tested, but there is nothing really to calibrate. The calibration would involve the measurement instrumentation that is used to actually measure the resistance change. Any connecting lead wire would introduce errors (higher resistance) depending on the type of measurement circuit used, and would have to be factored into the calibration, as well as self heating effects. etc. All this is well understood and "easy" to compensate for. Still seems any anomalous temperature readings would more likely be due to sensor location. Link to comment Share on other sites More sharing options...
RodneyS Posted August 13, 2015 Share Posted August 13, 2015 Still seems any anomalous temperature readings would more likely be due to sensor location. One way to test that hypothesis would be to follow Ian's proposal and add a second sensor at another DCA location. Then, after say a year, reverse the location of the two sensors. If, for example, Sensor A were to record higher temperatures than Sensor B in both Year 1 and Year 2, that would indicate a sensor issue. If, on the other hand, Sensor A were to record higher temperatures in Year 1, but then Sensor B records higher temperatures in Year 2, that would indicate a location issue. Link to comment Share on other sites More sharing options...
famartin Posted August 13, 2015 Share Posted August 13, 2015 DCA ASOS is in the middle of a big grassy field. Runways are well to the west (over 500 feet I believe). Potomac River is to the east about the same distance. Given its elevation and location near water, peak heating daytime readings at DCA should be somewhere in between DMH and NYG. Link to comment Share on other sites More sharing options...
uncle W Posted August 13, 2015 Share Posted August 13, 2015 do they have a mercury max/min as a back up to spot check the calibration of the aos censor?...if not they should... Link to comment Share on other sites More sharing options...
MN Transplant Posted August 14, 2015 Share Posted August 14, 2015 DCA 66, IAD 56 Link to comment Share on other sites More sharing options...
famartin Posted August 14, 2015 Share Posted August 14, 2015 On a radiational night, I'd expect that. DMH was even a little warmer. Link to comment Share on other sites More sharing options...
MN Transplant Posted August 14, 2015 Share Posted August 14, 2015 On a radiational night, I'd expect that. DMH was even a little warmer. Definitely. I'm often 6-10 degrees warmer than a mile or two away on these types of nights just due to drainage away from my slightly higher elevation street/neighborhood. My low is 63.2 today. I was just posting to catch Tenman's attention. 10 degrees difference or more can and should be expected. Link to comment Share on other sites More sharing options...
RodneyS Posted August 14, 2015 Share Posted August 14, 2015 DCA 66, IAD 56 The minimums were reached a little while later, at 64 for DCA and 53 for IAD. Link to comment Share on other sites More sharing options...
Ian Posted August 14, 2015 Share Posted August 14, 2015 You have a list of days you hit 90+ this year MN? Link to comment Share on other sites More sharing options...
MN Transplant Posted August 14, 2015 Share Posted August 14, 2015 You have a list of days you hit 90+ this year MN? 20, though 5 are due to rounding up (89.5 to 89.9). We have straddled the 90 line all year. Based on any instrument-related inflation, it could be anywhere between 14-20. Link to comment Share on other sites More sharing options...
CAPE Posted August 14, 2015 Share Posted August 14, 2015 do they have a mercury max/min as a back up to spot check the calibration of the aos censor?...if not they should... Yes they should. In order to verify the accuracy of a measurement, it should be checked against another measuring device (sensor) or test unit calibrated and traceable to a known standard. Link to comment Share on other sites More sharing options...
Deck Pic Posted August 17, 2015 Share Posted August 17, 2015 At least the heads are out of the sand and the FAA versus NWS stuff got put aside long enough to replace the sensors with the bent fins. It's probably a tip of the iceberg and really the daytime maxes have been off 2-4 and the nights 5-10+ for a long time so even the acknowledgment of the 2-2.5 during the daytime calibration comparisions is a step in the right direction. Now those who said I wore a tin foil hat will be very reluctant to change their stances but the cats out of the bag, thank you Jason and Mr Lee for your efforts to get this fixed. I'll offer a half-apology .I've probably been too hard on you and I am glad they replaced the sensor...The problem is the absurdities you still assert...like DCA has been off by 5-10+ degrees at night (that is an absurd statement I have proven wrong repeatedly).....I think you're not going to be very happy when the new sensor doesn't vindicate all the silly assertions you have made over the years.....last night Andrews was 67 and DCA 72....we are going to see even bigger spreads during serious UHI nights....whenever you have gotten specific over the last few years, you have done yourself a disservice, and fact checking you got annoying for everyone...You were on to something. No question. But I can understand why you lost a friend, as this issue has made you irrational....But I am happy they replaced the sensor.... Link to comment Share on other sites More sharing options...
Deck Pic Posted August 17, 2015 Share Posted August 17, 2015 Did you even read the article? On June 9 the sensor was half a degree off from the test equipment. After two days of temps not sure we know anything for sure other than it was replaced. It does seem like its a little closer aligned to wxbug temps today though for the most part it has been in the past. There have been a handful of odd days in recent times... Howard has been evangelical about this issue, and any facts that counter his assertions do not matter to him at all....He is not interested in facts when it comes to this. He has never ever been interested in a good faith fact based debate about these things...ever...we have been over it for years...and now he wants us all to kiss his ass after he has crapped on us for years when trying to engage him in a fact based debate....it's too bad, because the sensor has probably been reading too high the last couple years...and underneath all his vitriol was some merit.... Link to comment Share on other sites More sharing options...
Ian Posted August 17, 2015 Share Posted August 17, 2015 Howard has been evangelical about this issue, and any facts that counter his assertions do not matter to him at all....He is not interested in facts when it comes to this. He has never ever been interested in a good faith fact based debate about these things...ever...we have been over it for years...and now he wants us all to kiss his ass after he has crapped on us for years when trying to engage him in a fact based debate....it's too bad, because the sensor has probably been reading too high the last couple years...and underneath all his vitriol was some merit.... I don't know if there is evidence it has been running way warm for a long time or in all conditions. Their measurement in June was basically on target (slightly warm). Plus these are just point measurements. Not sure why they don't have a secondary system even if cheap to back up the main obs though. With about a week of evidence now it does seem that the new sensor has changed things to some degree... still not sure we can tell how much though. Obviously we all -- as weather geeks -- want it to show the most accurate thing possible. Plenty of us were arguing DCA should be warmer than other spots for legit reasons that still stand as you know. Link to comment Share on other sites More sharing options...
Ellinwood Posted August 17, 2015 Share Posted August 17, 2015 it does seem that the new sensor has changed things to some degree... I see what you did there. Link to comment Share on other sites More sharing options...
Ian Posted August 18, 2015 Share Posted August 18, 2015 I see what you did there. 90 at DCA, 85 at IAD. :o Link to comment Share on other sites More sharing options...
MN Transplant Posted August 18, 2015 Share Posted August 18, 2015 90 at DCA, 85 at IAD. :o On a south wind. If we ever went west again the whole improvement might be out the window. Link to comment Share on other sites More sharing options...
AvantHiatus Posted August 18, 2015 Share Posted August 18, 2015 DCA is simply a hotspot. No broken sensors, no missing link. Just gotta accept it for what it is. Link to comment Share on other sites More sharing options...
famartin Posted August 18, 2015 Share Posted August 18, 2015 The fact there was a shower at IAD at 11AM probably had some influence on its lower reading today. Link to comment Share on other sites More sharing options...
WEATHER53 Posted August 18, 2015 Share Posted August 18, 2015 The fact that a major metro area news agency ran the article and described who had been involved in the project and what was done was vindication for me. The immediate results thereafter also further vindication. Matt unfortunately demonstrated an inability to reconsider his position he has taken. DCA will upon occassion still be +5 to +10 on the nightime mins, it happens a considerable amount of time, and based on the circumstances I do not have a quarrel with that at times. However, in full snowcover and a frozen Potomac there is NO mechanism for that to occur as any potential heat producing resource would be blanketed. Does anyone really believe that a 15'X15' area can overwhelm cubic tons of atmosphere, snow cover, frozen river? Also, DCA is not at the corner where the Williard sits. It's surrounded by water to the ne/e/se/s and tree lined minimally travelled parkway to the west, and granted considerable urbanization further west . However, under the old measurment regime under the conditions I described DCA would be at 19, Andrews at 9, IAD at 7, BWI at 10 and Annapolis(bigger body of water for those who tote that) 12. That was always incorrect and will very likley no longer be occurring. So my decades long assertions, often childishly ridiculed here, have in fact proven to be true and for all of you who still think not I guess you must be concluding that everyone and everything in that article is "just as dumb as I am" Link to comment Share on other sites More sharing options...
WEATHER53 Posted August 18, 2015 Share Posted August 18, 2015 Howard has been evangelical about this issue, and any facts that counter his assertions do not matter to him at all....He is not interested in facts when it comes to this. He has never ever been interested in a good faith fact based debate about these things...ever...we have been over it for years...and now he wants us all to kiss his ass after he has crapped on us for years when trying to engage him in a fact based debate....it's too bad, because the sensor has probably been reading too high the last couple years...and underneath all his vitriol was some merit.... Bitter little man. I thought you had it on the ball, now with overwhelming evidence and actions contrary to your opinion and supportive of mine you resort to this. Your fact based debate defense was in fact absent of any fact as it has now turned out. I do not expect you to kiss my as* but I would suggest you get your head out of yours. Link to comment Share on other sites More sharing options...
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