Topic: New ASOS Temperature/Dewpoint System

[CW7491]

For those interested in such things and from a hint from a fellow forum member, I was able to find this PowerPoint of the replacement to the ASOS HO-1088 and DTS1. Replacement looks to be next fiscal year after operational testing this summer. Looks like they will use the Vaisala HMP155 in a passive shield for dewpoint and the HMP155’s optional remote temp probe in a RM Young aspirated shield for temperature.

https://fpaw.aero/sites/default/files/163/2-boutin-decadal-look-asos-lifecycle-upgrades.pdf

[TheBushPilot]

Wonder why it's taken them so long to adopt commercially available instrumentation? Red tape?

Also curious to know if they chose the HMP155 due to it's stability over longer periods since the gov't struggles with maintenance schedules.

But in all seriousness finding out they are rolling out with ASOS SLEP made my day. Thanks for keeping us in the loop.


Cheers

ASOS 2.0 before Davis VP3

[ValentineWeather]

Vaisala HMP155 in a RM Young aspirated shield for temperature and another in a passive shield for dewpoint.

https://fpaw.aero/sites/default/files/163/2-boutin-decadal-look-asos-lifecycle-upgrades.pdf

Interesting they decided to use commercially available instruments.

[jerryg]

Anyone besides me see that the instruments in the picture are located over gravel, not exactly a good example of how to set up a station.

[ValentineWeather]

It could be worse here is Sky Harbor's own heat island in Phoenix. There isn't even a weed around, just hard-packed ground and crushed rock next to the runway tarmac and maintenance road. With jets blowing hot exhaust out taking off and landing every few minutes. Not even the desert is this barren.   

[ValentineWeather]

Here's the aerial view, there is so much concrete and blacktop it's crazy.  It's actually much bigger than this, the Phoenix airport is just huge, and it's literally a heat island.
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[ASOSWX]

There was a requirement to have 1x1 or 2x2 (can't remember) patch of grass under the 1088, I always chuckled at that.  Previous to the ASOS,  the HO83 was usually sited with the F-420 winds and LBC, all separately (no array), and usually had "vegetation".

[CW7491]

The program manager has been responsive and updates this website: https://www.weather.gov/asos/CurrentEvents.html

The new TRH sensor will be deployed at select operational test and evaluation sites on 1 November with the rest of the ASOS sites being upgraded in 2024 and into 2025. The program manager said he will update the website with the specific OT&E sites when they are operational.

[ASOSWX]

The OT&E sites have been picked and the kits are being put together.  The ASOS Wind sensor replacement is about half complete.

[CW7491]

I assume they will replace the HO-1088 and the DTS1 at the OT&E sites, or will they run concurrently for a time?

[ASOSWX]

1088 and DTS1 go away on install.

[CW2274]

The OT&E sites have been picked and the kits are being put together. 

Would you be privy to where and when?

[CW7491]

Some install dates now made public. First one tomorrow in Annapolis, MD …
https://www.weather.gov/asos/CurrentEvents.html

[drew1021]

Thanks for the update!

[CW7491]

After a significant delay, they are back on track with the OT&E. KNAK is up and running with the remaining sites scheduled here …
https://www.weather.gov/asos/CurrentEvents.html

[txagwx]

Difference between ATL and FFC has changed since the new ASOS temp sensor was replaced.  FFC (Peachtree) reads colder!

[drew1021]

Are there any updates on the install progress of the new temp/dewpoint system that anyone may be aware of? NWS update page hasn’t indicated any since August 2023.
https://www.weather.gov/asos/CurrentEvents.html

[CW7491]

There had been an update on 5 September 2024 listing all the sites that had been updated to the new TRH equipment and the dates they were installed. It had also stated that that data would be analyzed for a 30 day period after the last installation making a recommendation to go to full deployment. Why that update as removed with no further update seems a bit odd. From following it over the past year plus, they’ve seemed to run into continual delays. Not sure if another delay accounts for it?

[drew1021]

You are likely correct that there have been unforeseen delays for whatever reason. Also the last update I saw didn’t mention the RM Young shield. I wonder if they’re still going to use it?

[CW7491]

From what I've read, I don't think there is any question to what equipment will be used. It is the Vaisala HMP155 with a remote temperature sensor option. The remote temperature sensor will be placed in an aspirated RM Young shield and the HMP155 humidity/dewpoint sensor will be placed in a separate passive shield. The government contracts have been awarded and it seems even the shields and sensors have been procured. From what I understand, they are simply testing the reliable incorporation of the new equipment in the existing ASOS system at select sites before they proceed with full implementation. Mr. Boutin is the program manager and is the one who updates the current events site as I understand it. He's even replied to me personally in the past, but they seemed to have tightened it up a bit recently not only with in the information on the current events page but also with contact info. A member here, ASOSWX, might have additional information if he is able to share given the sensitivities involved.

[CW7491]

Looks like the full installation will be completed in 2025 from the current events page.

An excel file has been created to track the installation status of the new TRH sensors. Once in the file select the TTd tab at top of the page …

https://www.weather.gov/media/asos/ASOS%20Sites%20by%20Equipment%20As%20Of%201_27_2025%20(1).xlsx

[ValentineWeather]

The aspiration shield at the KVTN site hasn't changed, but I have noticed the daily high and lows with my own setup using the Davis SHT31 and custom fan are very similar, so they may have changed sensors out here.
I can't tell by the PDF link what stations have been changed out. Maybe just don't understand how to read it. I have also noticed the ASOS humidity will reach 100% now, before it never reached or exceeded 96% even in fog, so have a feeling something has changed.

Here is the synoptic viewer of both sites, you can see highs yesterday 81 high both, low was -1 cooler at airport 39f. This is a huge difference from the way it used to be.

https://viewer.synopticdata.com/map/data/now/air-temperature/summary/E3958,KVTN/basic-weather/?layers=#map=9.76/42.9103/-100.413&sort=STID,asc

[CW7491]

Yeah, unfortunately they haven’t updated the excel file since Jan 27 despite saying it would be updated monthly. Excel isn’t always the cleanest display for sure. If you open the file, there are a row of tabs at the very top. The file opens with the ACU tab selected. If you slide scroll across the top row until you see the TTd tab. Select it and then slide scroll back on the file and you’ll see two columns: one is the 1088/DTS-1 column and an HMP-155 column. The file currently shows only 22 stations that have converted to the HMP155, but I know it’s more than that because I know KLAS has been completed but it shows it hasn’t been done. The file also displays the date the sites were converted. Hope this helps for when they actually update it

[ValentineWeather]

Thanks, they've only done one here in Nebraska, it looks like.

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[Wooks61]

Here is the synoptic viewer of both sites, you can see highs yesterday 81 high both, low was -1 cooler at airport 39f. This is a huge difference from the way it used to be.

https://viewer.synopticdata.com/map/data/now/air-temperature/summary/E3958,KVTN/basic-weather/?layers=#map=9.76/42.9103/-100.413&sort=STID,asc

That`s a useful link I didn`t know about. Thanks.
I didn`t realise it would show the sites this side of the pond as well.