Anomalous DCA anomalies?

[WEATHER53]

On September 17, 2015 at 9:03 AM, Ellinwood said:

Which is why it is dumb for anyone to claim a definitive victory one way or the other at this point. 1-2 summer/summer-like months is not a complete enough dataset.

How about a year? How  many more years would you and yours like?

Some of you are so caught up in decade old personality clashes that you cannot acknowledge data from several independent entities even when it slaps you right in the face

[RodneyS]

1 hour ago, MN Transplant said:

Here is the long-term chart of DCA vs IAD temps.

 

A most interesting chart, particularly for 1976 and 2009.  The former featured the greatest yearly temperature differential between the airports -- 5.9 degrees -- whereas the latter featured the smallest yearly temperature differential between the airports -- 1.7 degrees.  Could it be that a sensor problem at one of the airports can also explain each of those extremes?  

[MN Transplant]

54 minutes ago, RodneyS said:

A most interesting chart, particularly for 1976 and 2009.  The former featured the greatest yearly temperature differential between the airports -- 5.9 degrees -- whereas the latter featured the smallest yearly temperature differential between the airports -- 1.7 degrees.  Could it be that a sensor problem at one of the airports can also explain each of those extremes?  

I'm working on something that includes some of the other coop sites (primarily Beltsville since the Arboretum and Dalecarlia have problems of their own).  If we are to be skeptical (justifiably) of the 2014-15 temps at DCA because of the difference with IAD, the same has to be true then for the big heat in 1980. 

[WEATHER53]

1 hour ago, MN Transplant said:

I'm working on something that includes some of the other coop sites (primarily Beltsville since the Arboretum and Dalecarlia have problems of their own).  If we are to be skeptical (justifiably) of the 2014-15 temps at DCA because of the difference with IAD, the same has to be true then for the big heat in 1980. 

Speaking of the great heat of 1980 we broke that record of 32 consecutive nights not  below 70 at  DCA during our recent run with 35 in a row 

[BTRWx]

I can't believe there are eight pages about the dca weather sensor since last summer!  It makes me feel special.

www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/11/21/inside-washington-d-c-s-urban-heat-island-effect/

[Ellinwood]

9 hours ago, Tenman Johnson said:

How about a year? How  many more years would you and yours like?

Some of you are so caught up in decade old personality clashes that you cannot acknowledge data from several independent entities even when it slaps you right in the face

A year is a good amount of data. 1-2 months is not. I agree that the old sensor was running too warm based on the data we now have. I haven't been on the forums for a decade. All I wanted was a sufficient amount of data before reaching a conclusion. We now have a sufficient amount of data. I was being a good scientist, not a naysayer.

[WEATHER53]

On August 9, 2016 at 6:36 PM, RodneyS said:

As today marks the end of a year since the new temperature sensor was installed at DCA, here is an update comparing how many degrees (F) higher the temperature averaged at DCA than at IAD during the same calendar month (fractions of a month for August) immediately before and after installation of the new sensor:

Before                                  After    

August 10-31, 2014: 6.0     August 10-31, 2015: 4.1 

September 2014: 6.4          September 2015: 3.9    

October 2014: 6.1               October 2015: 3.7  

November 2014: 6.2           November 2015: 3.4  

December 2014: 5.4           December 2015: 2.5   

January 2015: 5.9               January 2016: 3.4     

February 2015: 4.9              February 2016: 2.9    

March 2015: 5.1                  March 2016: 2.9            

April 2015: 4.7                     April 2016: 2.8 

May 2015: 4.3                     May 2016: 2.0 

June 2015: 4.7                    June 2016: 3.1         

July 2015: 5.5                      July 2016: 3.2      

August 1-9, 2015: 6.3          August 1-9, 2016: 4.1      

Overall, for the year ended August 9, 2015, DCA averaged 5.4 degrees higher than IAD, whereas for the year ended August 9, 2016, DCA averaged 3.2 degrees higher than IAD.  Breaking these averages into maximum and minimum differentials, for the year ended August 9, 2015, DCA's average maximum was 3.7 degrees higher than IAD's and its average minimum was 7.2 degrees higher.  In contrast, for the year ended August 9, 2016, DCA's average maximum was 1.1 degrees higher than IAD's and its average minimum was 5.2 degrees higher. 

While the above comparisons are not absolute proof that the DCA sensor was reading too high for a long period of time prior to its August 10, 2015 replacement, I think any other explanation is pretty implausible.  Of particular interest in this regard may be the fact that the DCA May 2015 average temperature of 73.2 degrees set a record high for that month.  However, that temperature barely broke the previous DC  May record of 73.0 established in 1991. Had the DCA sensor been replaced on May 1, 2015, I think it's safe to say that the 1991 record would still stand.    

All 12 months and all 1.5 to 3 so not even a small margin 

[WEATHER53]

Interesting development. Annapolis was the station I often used to rebuke claims of DCA accuracy over issues like "around a body of water" as Annapolis usually did not display the same temperature and humidity aberrations that Dca did

Annapolus now is no longer included in the "other local weather stations" section that still does include BWI, Dulles, Andrews.

Interesting 

[Ellinwood]

Must be a conspiracy. I suggest you look into this further.

[WEATHER53]

3 hours ago, Ellinwood said:

Must be a conspiracy. I suggest you look into this further.

I am right about everthing else so very well may do. Let me know when assertions that you have made for over a decade are confirmed and we will throw a party for your sorry ass.

[Ian]

This thread is also fairly conclusive for which posters have the biggest heads. 

The CWG station is tracking pretty close to DCA so far. Sensor was probably running too warm for a while. Only a dummy doesn't understand UHI tho. As one example both DCA and the Post have 7 80-degee or higher lows this year. Which according to some is impossible because DCA reads 10 degrees too warm at night.

[MN Transplant]

Here's maybe the most telling graph.  Monthly max temps only (little UHI contamination).  IAD and Beltsville are generally close, and combining them reduces the chance for bias with one or the other.  We can indeed see that 2014-15 was anomalous and you could make a good case for sensor problems.  However, prior to that, and back to the mid-80s there is a general consistency, so Tenman's statement above that he has been talking about this for over a decade means that he was wrong that entire time.  Now, the interesting question is prior to 1985, how much of that is instrument/location/UHI, etc?

 

[WEATHER53]

6 hours ago, Ian said:

This thread is also fairly conclusive for which posters have the biggest heads. 

The CWG station is tracking pretty close to DCA so far. Sensor was probably running too warm for a while. Only a dummy doesn't understand UHI tho. As one example both DCA and the Post have 7 80-degee or higher lows this year. Which according to some is impossible because DCA reads 10 degrees too warm at night.

Only tiny little people can't admit when they were wrong

its not the facts that have been revealed that you are denying, it's the personalities that have gotten your goat 

[WEATHER53]

4 hours ago, MN Transplant said:

Here's maybe the most telling graph.  Monthly max temps only (little UHI contamination).  IAD and Beltsville are generally close, and combining them reduces the chance for bias with one or the other.  We can indeed see that 2014-15 was anomalous and you could make a good case for sensor problems.  However, prior to that, and back to the mid-80s there is a general consistency, so Tenman's statement above that he has been talking about this for over a decade means that he was wrong that entire time.  Now, the interesting question is prior to 1985, how much of that is instrument/location/UHI, etc?

 

Gobbledegook bull****

[WEATHER53]

On August 9, 2016 at 6:36 PM, RodneyS said:

As today marks the end of a year since the new temperature sensor was installed at DCA, here is an update comparing how many degrees (F) higher the temperature averaged at DCA than at IAD during the same calendar month (fractions of a month for August) immediately before and after installation of the new sensor:

Before                                  After    

August 10-31, 2014: 6.0     August 10-31, 2015: 4.1 

September 2014: 6.4          September 2015: 3.9    

October 2014: 6.1               October 2015: 3.7  

November 2014: 6.2           November 2015: 3.4  

December 2014: 5.4           December 2015: 2.5   

January 2015: 5.9               January 2016: 3.4     

February 2015: 4.9              February 2016: 2.9    

March 2015: 5.1                  March 2016: 2.9            

April 2015: 4.7                     April 2016: 2.8 

May 2015: 4.3                     May 2016: 2.0 

June 2015: 4.7                    June 2016: 3.1         

July 2015: 5.5                      July 2016: 3.2      

August 1-9, 2015: 6.3          August 1-9, 2016: 4.1      

Overall, for the year ended August 9, 2015, DCA averaged 5.4 degrees higher than IAD, whereas for the year ended August 9, 2016, DCA averaged 3.2 degrees higher than IAD.  Breaking these averages into maximum and minimum differentials, for the year ended August 9, 2015, DCA's average maximum was 3.7 degrees higher than IAD's and its average minimum was 7.2 degrees higher.  In contrast, for the year ended August 9, 2016, DCA's average maximum was 1.1 degrees higher than IAD's and its average minimum was 5.2 degrees higher. 

While the above comparisons are not absolute proof that the DCA sensor was reading too high for a long period of time prior to its August 10, 2015 replacement, I think any other explanation is pretty implausible.  Of particular interest in this regard may be the fact that the DCA May 2015 average temperature of 73.2 degrees set a record high for that month.  However, that temperature barely broke the previous DC  May record of 73.0 established in 1991. Had the DCA sensor been replaced on May 1, 2015, I think it's safe to say that the 1991 record would still stand.    

Rodney-thank you for your excellent work and please do not let the detractors ruin your efforts. I probably was too celebratory in the confirmation of my ideas but I  took a lot of hammering over the years and with the info staring them in the face they cannot handle it so they resort to personal attacks, data distortion and attempted introduction of other data methods not already in evidence nor part of your work .

[mattie g]

15 minutes ago, Tenman Johnson said:

Gobbledegook bull****

DT...that you?

[WEATHER53]

3 minutes ago, mattie g said:

DT...that you?

No he was run off of here like many other knowledgeable contributors because he too elected to vigorously defend his concepts and experiences

[Ian]

6 hours ago, Tenman Johnson said:

Only tiny little people can't admit when they were wrong

its not the facts that have been revealed that you are denying, it's the personalities that have gotten your goat 

You are the Donald Trump of the forum. 

[RodneyS]

19 hours ago, Tenman Johnson said:

Rodney-thank you for your excellent work and please do not let the detractors ruin your efforts. I probably was too celebratory in the confirmation of my ideas but I  took a lot of hammering over the years and with the info staring them in the face they cannot handle it so they resort to personal attacks, data distortion and attempted introduction of other data methods not already in evidence nor part of your work .

I present data, you decide.  However, I do think that there is a consensus that the DCA sensor began to malfunction long before it was replaced last August.  Which raises the question of how often does something like that happen, not only here but all over the world. 

[wxdude64]

32 minutes ago, RodneyS said:

I present data, you decide.  However, I do think that there is a consensus that the DCA sensor began to malfunction long before it was replaced last August.  Which raises the question of how often does something like that happen, not only here but all over the world. 

That is an interesting question. I'd like to see some data on that myself, and then get figures on which way it leans, warmer vs colder than actual.

My personal guess is 80-90% read high that do malfunction, but the data would answer those questions.

[Ian]

1 hour ago, RodneyS said:

I present data, you decide.  However, I do think that there is a consensus that the DCA sensor began to malfunction long before it was replaced last August.  Which raises the question of how often does something like that happen, not only here but all over the world. 

Big can of worms. My guess is there are tons of places that are off. I know it's supposed to be a specific reading but people would generally be better off focusing on trends rather than specifics in a lot of cases. I know that's a lot easier said than done and I like specifics myself. But I suspect these issues are endemic. That's partly why the whole DCA thing never got me in a major tizzy.

[WEATHER53]

3 hours ago, RodneyS said:

I present data, you decide.  However, I do think that there is a consensus that the DCA sensor began to malfunction long before it was replaced last August.  Which raises the question of how often does something like that happen, not only here but all over the world. 

I would agree and have maintained for decades that there was something wrong with the DCA sensor but the "consensus" you mentioned still has some adamant opposition

if you have never been by it it's not like next to the Willard, all pavement and buildings for blocks.  There is water to the east north and south, a tree laden parkway almost right through it, and pavement and buildings to the sw-nw  so not really the UHI megalith that some portray it to be-a location at the Willard Would  be  right in the middle of UHI. Annapolis is a great comparison and deflector of the "body of water" defense that is offered but interestingly it has now been removed as one of the "other local weather" stations on NOAA site for DCA  

Good work on your part and thank you for presenting it 

 

 

[MN Transplant]

7 minutes ago, Tenman Johnson said:

I would agree and have maintained for decades that there was something wrong with the DCA sensor but the "consensus" you mentioned still has some adamant opposition

if you have never been by it it's not like next to the Willard, all pavement and buildings for blocks.  There is water to the east north and south, a tree laden parkway almost right through it, and pavement and buildings to the sw-nw  so not really the UHI megalith that some portray it to be-a location at the Willard Would  be  right in the middle of UHI. Annapolis is a great comparison and deflector of the "body of water" defense that is offered but interestingly it has now been removed as one of the "other local weather" stations on NOAA site for DCA  

Good work on your part and thank you for presenting it 

 

 

 

Annapolis either malfunctioned or stopped sending data on the 13th after the 6am ob.

[mattie g]

2 hours ago, MN Transplant said:

 

Annapolis either malfunctioned or stopped sending data on the 13th after the 6am ob.

You need to get checked for chemtrail poisoning, because HAARP has definitely gotten to your head.

[Inverted_Trough]

I agree that this issue is pervasive.  But I also think some airports are worse than others.  DCA deserves all the skepticism they get.

DCA has continued running 2-3 degrees hotter (for daily maxes)  than all nearby ASOS sites for the past couple months.  That's a stark change from the prior several months, where it was running very close to other ASOS stations for highs.  It could be a microclimate that's developed over the past couple months....or maybe their sensor has "drifted" and needs recalibration.  The longer this continues, the more I suspect it's the latter.

[RodneyS]

12 hours ago, Inverted_Trough said:

I agree that this issue is pervasive.  But I also think some airports are worse than others.  DCA deserves all the skepticism they get.

DCA has continued running 2-3 degrees hotter (for daily maxes)  than all nearby ASOS sites for the past couple months.  That's a stark change from the prior several months, where it was running very close to other ASOS stations for highs.  It could be a microclimate that's developed over the past couple months....or maybe their sensor has "drifted" and needs recalibration.  The longer this continues, the more I suspect it's the latter.

The only two airports that I have historical data for are DCA and IAD, but the average difference in temperature this summer at those airports has actually been slightly less than the average difference since Dulles opened in late 1962.  Specifically:

June 2016: 3.1 degrees higher at DCA vs. 3.6 degrees higher June historical average difference.

July 2016: 3.2 degrees higher at DCA vs. 3.6 degrees higher July historical average difference.

August 1-19, 2016: 3.4 degrees higher at DCA vs. 3.4 degrees higher August historical average difference.

 

[winterymix]

Isn't it disappointing that snowfall and temperature measurements

seem to have had multiple intervals of quality control issues at DCA?

This is not the Manhattan Project, it shouldn't be difficult at all to have

sustained high quality data.

[WEATHER53]

1 hour ago, winterymix said:

Isn't it disappointing that snowfall and temperature measurements

seem to have had multiple intervals of quality control issues at DCA?

This is not the Manhattan Project, it shouldn't be difficult at all to have

sustained high quality data.

This can be difficult to attain if there is the operating platform that it's an FAA facility and nobody other that weather weenies really care if 22 or 15" of snow fell or if the low was 19 versus 10

[MN Transplant]

More interesting data about 1980.  While DCA had their hottest August on record and racked up the 90 degree days, IAD's August was only the 9th hottest on record and BWI's 7th.  Similar pattern for Sept.  Makes me question the # of 90 days record.  Could be that 2010 is the clear winner.

[RodneyS]

10 hours ago, MN Transplant said:

More interesting data about 1980.  While DCA had their hottest August on record and racked up the 90 degree days, IAD's August was only the 9th hottest on record and BWI's 7th.  Similar pattern for Sept.  Makes me question the # of 90 days record.  Could be that 2010 is the clear winner.

1980 meteorological summer average difference in DCA/IAD temperatures was 5.4 degrees, 4th all-time.  1976 meteorological summer had highest average difference of 6.2 degrees, followed by 1970 at 6.1 and 1983 at 5.8 (2010 was 3.5).  August 1980 had a difference of 5.7 degrees, tied for third with 1983, behind 1970 at 6.8 and 2014 at 5.9 (2010 was 3.1).  September 1980 had a difference of 6.3 degrees, third behind 1983 and 2014, each at 6.4 degrees (2010 was 4.2).