CartoSky - Interactive Weather Viewer * Lots of Updates *

hawkstwelve · June 11

(Update 7/9/26: A lot of features outlined in the below post are now live and many improvements have been made since the initial launch. Thread updates below with further details.)

CartoSky Public Beta is Live

https://cartosky.com

After several months of development, I'm excited to have you all check out CartoSky.

CartoSky is a map-first weather platform focused on interactive model, forecast, and observation analysis. Everything is built around a fast weather viewer - I originally started building it because I wanted a faster, cleaner, more modern way to analyze weather data without constantly switching between multiple sites.

The current model lineup includes HRRR, GFS, NAM (which will soon be replaced by the RRFS), ECMWF, NBM, AIFS, and AIGFS, plus GEFS and EPS on the ensemble side. Forecasts include NDFD, SPC, CPC, and WPC. Obs coverage includes MRMS radar and precip, satellite, NWS hazards, and current analysis. There's also a Forecast page where you can pull hourly, 7-day, and extended forecasts as well as NWS AFDs for any location.

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TWF Integration

One of the key features that helped inspire CartoSky was tighter integration with The Weather Forums. You can share directly to any forum thread straight from the map - current view, model, and forecast hour included. No screenshots to upload, and you can draft your post directly in the share dialog. You'll need a CartoSky account and your TWF account linked under Integrations in your account settings. Takes about a minute to set up.

What's Coming

The beta is about getting the core experience solid but over the next couple months here are some things I plan to add:

* Near term: NWS warnings overlay on radar, expanded satellite bands, extended SPC and CPC outlooks, additional models

* Medium term: GIF/animation export, model comparison tools, model consensus and probabilities, meteograms

* Longer term: Advanced event analysis tools, expanded sharing options, and additional forecast products

Feedback

This is a beta release. While I've spent a lot of time testing, there will undoubtedly be bugs and things I haven't thought of, especially on mobile as the site was designed with desktops in mind. As the solo developer on this, your feedback is genuinely what I need to polish things up before the busy season starts this fall/winter. If you run into issues, have performance concerns, or want to suggest a feature, please let me know either in this thread or hit the Feedback button available throughout the site. Any feedback is welcome - positive or negative!

https://cartosky.com

hawkstwelve · June 11

Already caught and fixed a bug with the satellite product stalling on animation that someone ran into.

Thanks to those of you who are checking out the site!

Rubus Leucodermis · June 11

Just took a quick look and that is an impressively polished web site.

hawkstwelve · June 11

44 minutes ago, Rubus Leucodermis said:

Just took a quick look and that is an impressively polished web site.

That's nice to hear, thank you. A ton of time and work went into this over the past six months so I appreciate that feedback!

Chewbacca Defense · June 11

Yeah, I've been checking it out as well and I really like what I am seeing! Nice work!

hawkstwelve · June 12

50 minutes ago, Chewbacca Defense said:

Yeah, I've been checking it out as well and I really like what I am seeing! Nice work!

Really appreciate it, glad you are enjoying it! Let me know if you run into anything or have suggestions.

T-Town · June 12

It’s super cool. I’m always on my phone instead of a desktop and so far it looks pretty good in mobile. The city labels are an exception though, when I zoom in they don’t really align to the dots on the map.

A handy feature for the viewer would be the ability to speed up or slow down the maps.

Im interested in the meteograms, which I believe you said are a roadmap item.

hawkstwelve · June 12

3 minutes ago, T-Town said:

It’s super cool. I’m always on my phone instead of a desktop and so far it looks pretty good in mobile. The city labels are an exception though, when I zoom in they don’t really align to the dots on the map.

A handy feature for the viewer would be the ability to speed up or slow down the maps.

Im interested in the meteograms, which I believe you said are a roadmap item.

Great feedback, thanks! Nice to hear mobile is holding up. I developed it with a desktop view in mind but have been working hard over the recent weeks to make it more mobile friendly. I will definitely file a bug report for the city labels not aligning and look into getting that fixed.

The animation speed is already noted as I completely agree - I'll get that implemented very soon.

I'm excited to start work on the meteograms. I'm hoping to develop something similar to WB's and a lot of the background data/processes are already in place, so hopefully it will all work out well.

Tanis Leach · June 12

This is a great site so far! Also looks more YouTube-friendly for a frugal me (so no ads appear). Is this going to be integrated for easy sharing on other sites?

hawkstwelve · June 12

4 hours ago, Tanis Leach said:

This is a great site so far! Also looks more YouTube-friendly for a frugal me (so no ads appear). Is this going to be integrated for easy sharing on other sites?

Thanks! That's an interesting use case I hadn't thought about - glad the clean interface works well for that.

On the sharing, it was developed as a sort of sister-site to TWF so that's where I put the initial focus for sharing. That said, you can already share direct links to any map view and download the generated screenshot, and expanding easy sharing to other platforms is on the roadmap. I'll probably try FB and X initially. Let me know if there's another platform you'd like and I'll make a note!

Tanis Leach · June 12

5 hours ago, hawkstwelve said:

Thanks! That's an interesting use case I hadn't thought about - glad the clean interface works well for that.

On the sharing, it was developed as a sort of sister-site to TWF so that's where I put the initial focus for sharing. That said, you can already share direct links to any map view and download the generated screenshot, and expanding easy sharing to other platforms is on the roadmap. I'll probably try FB and X initially. Let me know if there's another platform you'd like and I'll make a note!

We do have a PDX based weather group in discord. That could be another.

Also from that, I was told to relay the message for feedback: they thought the basemap was a little weird but wouldn't explain why it was wierd.

hawkstwelve · June 12

50 minutes ago, Tanis Leach said:

We do have a PDX based weather group in discord. That could be another.

Also from that, I was told to relay the message for feedback: they thought the basemap was a little weird but wouldn't explain why it was wierd.

Discord is a good call I hadn't thought of. I'll add it to the list for when I get to expanding sharing platforms.

For the basemap - I did push some rendering improvements this morning so it may already be better. If they're still seeing something off after that, having them hit the Feedback button on the site would really help me nail down what they're seeing. Hard to chase down without knowing exactly what looked off.

SeattleSmokeLayerFan · June 12

I think the website is really nice. Just a few suggestions.

I noticed the time frame slider for the model output is a bit laggy until everything loads/caches, and there is a desync between the value tooltips and the map coloring itself (e.g. surface temps). The animation is smooth, so I think the same performance could be achieved for the slider as well. I also noticed a bug that if I slide too early, sometimes it freezes on the old frame and never updates until I slide again.

If I switch between a model, it would be useful for it to land on the same/nearest timeframe (for quick comparisons). Or even cooler, I think a side by side comparison view would be nice. Also, run to run deltas would be useful as well.

As for technical aspects, I would suggest using Page Insights to identify performance improvement opportunities: https://pagespeed.web.dev/analysis/https-cartosky-com-viewer/q2c2xhqq1b?form_factor=desktop

In the future, adding more chart styles (like the spaghetti ones Shawnigan posts) as well as other things like SSTs (ENSO monitoring), MJO, PNA, etc. would make this a one stop shop for all weather analysis.

SeattleSmokeLayerFan · June 12

Also I might be wrong, but the screenshot seems to be generated on the server side, hence the couple seconds of wait. But I think it can be achieved much more efficiently using client-side APIs to take a direct screenshot of the `<canvas>` used to render the map. I tried it via inspect element, and it instantly generated the screenshot from the browser itself.. though this would not include the key/branding which needs to be appended programmatically.

hawkstwelve · June 12

1 hour ago, SeattleSmokeLayerFan said:

I think the website is really nice. Just a few suggestions.

I noticed the time frame slider for the model output is a bit laggy until everything loads/caches, and there is a desync between the value tooltips and the map coloring itself (e.g. surface temps). The animation is smooth, so I think the same performance could be achieved for the slider as well. I also noticed a bug that if I slide too early, sometimes it freezes on the old frame and never updates until I slide again.

If I switch between a model, it would be useful for it to land on the same/nearest timeframe (for quick comparisons). Or even cooler, I think a side by side comparison view would be nice. Also, run to run deltas would be useful as well.

As for technical aspects, I would suggest using Page Insights to identify performance improvement opportunities: https://pagespeed.web.dev/analysis/https-cartosky-com-viewer/q2c2xhqq1b?form_factor=desktop

In the future, adding more chart styles (like the spaghetti ones Shawnigan posts) as well as other things like SSTs (ENSO monitoring), MJO, PNA, etc. would make this a one stop shop for all weather analysis.

39 minutes ago, SeattleSmokeLayerFan said:

Also I might be wrong, but the screenshot seems to be generated on the server side, hence the couple seconds of wait. But I think it can be achieved much more efficiently using client-side APIs to take a direct screenshot of the `<canvas>` used to render the map. I tried it via inspect element, and it instantly generated the screenshot from the browser itself.. though this would not include the key/branding which needs to be appended programmatically.

This is really great stuff!

For the bugs - I will look into making the scrubber/slider more performative, as well as the desync issue between value tooltips and map coloring. Similar to animation, it's a tradeoff between making the user wait for a bit for a proper warm cache to load vs allowing quick scrubbing right when they start. I'll try to lean it more towards the former. I'll also file a bug report on GitHub for the sliding too early and freezing one. I ran into that earlier but thought I had it mostly ironed out. Definitely worth another look.

For the performance insights - I use a mixture of a custom-built admin dashboard which provides various performance metrics as well as some third party tools. Most of the metrics look pretty good but as is always the case, it's hard for them to tell the whole story and find edge cases.

For the recommended features - Completely agree on having it land on the same forecast hour when switching models/products. I ran into issues since some models don't support variables that others do but there is probably a happy medium I can find. Side-by-side comparison as well as deltas are on the roadmap, as are meteograms and possibly Skew-T diagrams. I like the mention of those other charts too and they might fit well on a new page. Good recs!

Finally, for the screenshot - I actually started with client-side capture and it was nearly instant with legend and branding included. The issue I ran into was viewport consistency. To try and mitigate differences between mobile/desktop I tried forcing a fixed output resolution but that caused the generated screenshot to differ from what was actually on the screen at the time of sharing, which felt like a trust issue for showing what the user wants to share. Server-side was the more reliable path for now but if I could find a way to make client-side work with differing viewports I definitely will revisit it.

hawkstwelve · June 15

Quick update

Been a busy few days since the beta went live. Between session replays, your reports in this thread, and my own testing, here's what's been fixed/added/improved so far:

Added animation playback speed control
Fixed multiple animation playback issues, including continuous loop behavior and stall conditions that were cutting playback short
Fixed a bug where the forecast hour would reset to F00 when switching models or variables - it now holds your current hour or jumps to the closest available one
Fixed city labels showing wrong values during animation and scrubbing
Significantly improved forecast hour scrubbing performance - less lag and fewer freezes when moving fast
Fixed an issue where SPC outlook data could be stale and not reflect the latest update
Fixed the share screenshot to correctly generate legends for CPC and SPC products
Improved contour line load times via caching improvements
Various basemap improvements for smoother zooming, rendering, and city label display
Improved the mobile control panel layout on iPhones, including a fix to the region selector that was getting cut off
Improved location search functionality on forecast page and map viewer

Keep the feedback coming. This is exactly the kind of stuff the beta is for. If something looks off, feels slow, or just doesn't behave the way you'd expect, drop it here or hit the feedback button on the site. Additional features as outlined in the top post will start to be added soon.

hawkstwelve · June 21

Side note: I am doing a full refactor of the city values. Things might be a bit funky until I iron out the issues.

Rubus Leucodermis · June 21

On 6/12/2026 at 11:17 AM, SeattleSmokeLayerFan said:

If I switch between a model, it would be useful for it to land on the same/nearest timeframe (for quick comparisons). Or even cooler, I think a side by side comparison view would be nice. Also, run to run deltas would be useful as well.

I’ve noticed this when switching between models, too. What I think is going on is that a given frame is just N frames back in the model run (for whatever value of N). So if the most recent versions of some models differ (which is pretty common, as some come out faster than others) the time jumps around by the difference in model initiation time. This is contrary to what WeatherBell does and thus contrary to what I (and presumably most users) would expect. Hopefully not too hard to fix.

Also, if @hawkstwelve needs coding help, that is my career background.

hawkstwelve · June 21

3 hours ago, Rubus Leucodermis said:

I’ve noticed this when switching between models, too. What I think is going on is that a given frame is just N frames back in the model run (for whatever value of N). So if the most recent versions of some models differ (which is pretty common, as some come out faster than others) the time jumps around by the difference in model initiation time. This is contrary to what WeatherBell does and thus contrary to what I (and presumably most users) would expect. Hopefully not too hard to fix.

Also, if @hawkstwelve needs coding help, that is my career background.

Yeah, that's a part of it. I think another aspect is different forecast hour cadences between models. HRRR, for example, has hourly forecast increments, while GFS is 3-hourly through 240 and then 6-hourly after that, so switching models does not always have a clean 1:1 forecast hour match.

I had done some work to help alleviate this issue where it should preserve the valid time as closely as possible when switching models, then fall back to nearest available forecast hour when there isn't an exact match (with accompanying toast notification). But if it's still jumping around more than expected that's definitely something I'll work to tighten up.

And I appreciate the offer. Always open to any help. The repo is public here. Feel free to poke around, open an issue, or submit a PR if you spot something you want to tackle. I'm currently working on refactoring the city value pipeline, adding to the new Climate page (thanks to @SeattleSmokeLayerFan for the suggestion), and ironing out the new comparison tool (especially on mobile).

hawkstwelve · June 23

Lots of ongoing development:

Added a side-by-side comparison tool directly from the map viewer
Added a difference mode inside the comparison tool, making it easier to see deltas between models, variables, and run times
Added NWS warnings to the radar product
Expanded satellite products with Mid-Level Water Vapor, Upper-Level WV, and Visible bands
Expanded SPC outlook support to days 4-8 when available
Expanded CPC outlook support to week 3-4, monthly, and three month
Added a live radar preview card to Forecast page
Refactored the city value pipeline; many more cities now show corresponding values, including higher zoom levels
Improved screenshot generation speed and added additional resiliency so shares are less likely to fail or capture incomplete frames

Still on deck: meteograms, GIF/trend export, additional model support, and more screenshot improvements. The Forecast page is being expanded into a fuller analysis hub - model charts, consensus tools, and probability products are all planned. This work will take a while but as long as my server resources can support it, I'm looking forward to getting this built out.

Side note: the new comparison tool (both side-by-side and difference modes) is still undergoing polish, logic, and layout improvements, especially on mobile/tablet. Please let me know if you run into anything that isn't working right.

hawkstwelve · June 26

Added model charts/meteograms to the Forecast page. This includes a compare mode, for comparing ECMWF/GFS/AIFS/NBM for a searched location, as well as a model detail mode, for getting data from a particular model. Please let me know if you run into any issues with this new feature set.

Ensemble charts are up next but first I'll be taking a breather for a few days to take my sons camping. Ensemble work will begin next week!

hawkstwelve · June 30

Heads up: I'm going to be doing some fairly large refactoring of the backend pipeline in order to better support ensemble members and associated meteograms, among other things. This may cause some sporadic issues over the next 24-48 hours as I get any bugs ironed out.

hawkstwelve · July 9

Quick CartoSky beta update. I’ve pushed quite a few improvements and features over the last couple weeks.

Biggest additions:

Added ensemble meteograms, including mean and per-member charts
Added ensemble percentile and probability maps
Added GIF export for both forecast-hour animations and run-to-run trends
Redesigned the share modal to make image/GIF/link sharing easier, including options that do not require a CartoSky account or TWF integration
Added a new Today tab on the Forecast page with additional current-day forecast details, recent observed precip, etc.
Added roads to the basemap for better map context and visibility
Improved loading/performance across the viewer, including faster animation behavior
Fixed several comparison tool logic issues in both split and difference modes
Made a lot of behind the scenes pipeline improvements to improve efficiency and reliability

With these additions a good chunk of the OP roadmap is now live. Next items up will be replacing NAM with RRFS (once upstream data feed from NOAA is reliably available), adding AIFS ensembles, expanding meteogram charts and percentile/probability maps to additional variables, exploring Skew-T diagrams, adding additional items on the Climate page, and refining all the new features since beta launch.

Some example screenshots below:

Thanks to those that have used the site and provided feedback - some of the stuff added since beta was a direct result of recommendations from all of you. As always, additional feedback is welcome. If anything looks off, feels slow, or behaves weirdly, let me know.

hawkstwelve · Tuesday at 03:26 PM

Heads up: two issues from recent infrastructure work are fixed and recovering as of this morning. Recent precipitation (MRMS 6h/24h/72h) layers were unavailable for part of today but they're back as of now. Current Analysis temporarily shows a shorter history than usual. The full ~11-hour timeline rebuilds automatically over the next 12 hours as new analyses come in. Radar, satellite, and all forecast models were unaffected.