brettjrob

Checking in for my annual-ish update: we've just added FREE Euro data for select surface/precipitation fields at 6-h intervals! This also includes new city-focused zooms across the country for the Euro maps with population centers labeled, something I don't think you'll find elsewhere (free or otherwise). We've also revamped the website a bit and added RTMA, NDFD, and various other non-model maps in the same web framework as our models. You can switch between model and non-model products while staying on the same zooms. We are planning to add looping/animated GIF capabilities to RTMA in the next few weeks. I hope everyone enjoys the new products, and feel free to leave feedback here (or through our contact form). To address a likely question upfront: there are currently no plans to turn Pivotal Weather into a subscription service, aside from commercial licensing for business-oriented users (people using our site routinely to make money or make business decisions). We are hoping that ad revenue, combined with support from the community, will sustain the new products and even allow us to add more Euro data in the future. If you'd like to see this happen, there are two things you can do to help: 1. Use Pivotal Weather to view as much of your preferred model data as we have available, Euro or otherwise! 2. If you can afford it, consider donating to our Patreon here: https://www.patreon.com/pivotalweather

Thanks for the feedback! In UI design, there's often some tradeoff between powerful features and simplicity of presentation. We try to strike the right balance, but probably lean more toward packing in extra features where possible, even if it sometimes makes the UI more complex. I know several of the other popular NWP graphics sites use a loop presentation by default, and that's something we've resisted to this point, out of concern for mobile users' bandwidth (e.g., if a 384-hour GFS loop is the first thing that loads when you hit the site, you may be pulling down 5-10 MB of data right away). We're continuing to evaluate that and may change the default mode in the future, though. If you or anyone else here has a specific suggestion on how the interface or experience could be improved, don't hesitate to let us know. If we get consistent feedback about a specific aspect of the site, there's a good chance we'll take it into account in future updates.

This is available on our Loop animation mode. We just reshuffled our UI a bit earlier this week in an attempt to make all our looping and animation options more visible. Under "Animation," the option "Forecast Loop" is similar to what several other sites offer (preloading all hours of a forecast with a slider). You can also view a Trend Loop (dProg/dt) in the same format. Here's an example: http://www.pivotalweather.com/model.php?m=nam&p=snku_acc&fh=loop&r=conus&dpdt=&mc=

It's been awhile since I've updated this thread, but quite a few new features have been added to PW in recent months: Soundings for Canadian (GDPS and RDPS) and GFS-FV3 (I believe we are currently the only free site with these) Soundings now available globally (GFS, GFS-FV3, and GDPS) NWS Advisories/Warnings, NDFD, WPC, CPC, and QPE/snow analysis maps available under "OTHER MAPS" tab on main site menu Data value readout on mouse hover now available in animations Model Comparison mode: toggle between forecasts from all models on our site for the time and product you're viewing without flipping tabs! You can also generate animated GIFs comparing the models this way. Example: http://www.pivotalweather.com/model.php?m=nam&p=snku_acc&rh=2019011018&fh=72&r=us_ma&dpdt=&mc=bl Just wanted to highlight some of these as more winter threats appear on the horizon. As always, feel free to respond here or DM me if you have any questions, comments, or suggestsion!

The current 7-10 day period is looking pretty grim to me. This week's string of southwest flow days is highly flawed, with Saturday at least offering some legitimate potential given CI. Then the pattern goes back to pure ugliness for at least 4-5 days heading through Memorial Day weekend into mid next week. Hurts, coming on the heels of perhaps the biggest waste of a late May longwave western trough I've seen (last week).

Wednesday is definitely worth watching. It's a flawed synoptic setup, but rejoice ye all, for it is May and such things can be overcome! If morning crapvection persists across the warm sector into the afternoon, as suggested by the Euro and GFS, then the most interesting threat may be confined to the Red River and NW TX. The NAM's idea opens the whole dryline up to SW KS for fun, but I don't trust its handling of CI, especially at this range. Either way, low-level shear appears to be the main limiting factor right now, primarily due to a weakness around H7 (not surprising for a closed low). Again, though... it's mid May now, and nothing with adequate moisture and 35 kt of bulk shear can be written off.

Although we've seen most of the Plains drought-free by late spring the last two years, what's most striking on those DM maps is that the most significant drought nationwide is in the Southeast. I can't recall seeing that since 2007.

The crappy closed low next Tue-Wed reminds me in a really vague sense of 15 May 2013. Mind you, there wasn't a massive east coast trough then. But it is evidence of how these barotropic-ish closed lows whose shear profiles leave something to be desired can still get the job done in May.

00z 4 km CAMs unanimous on an intense but slightly elevated supercell streaking across south central OK tomorrow evening. I can recall an event around this time last year with some similarities and a similar consensus (over NW OK and S KS) where the CAMs said "just kidding" by late morning the day of, so nothing's assured. The SBCINH is awfully formidable even right at 00z, and I have little doubt it will require a mesolow with localized enhanced convergence to pop off a storm at all. Fingers crossed for a nice mothership at sunset dumping some baseballs and putting on a highly visible light show for awhile after dusk.

Unfortunately, the 12z NAM and ECMWF both now support the idea of wave timing ~6 h too early, resulting in veered and anemic flow around H85 along the dryline. Leaning more and more toward a primary large hail threat for now.

Not my intention at all. Would note the GFS and Canadian have been relatively steadfast in depicting veered H85 as an issue, though. Euro has been more encouraging on several recent runs.

dProg/dt on the GFS for 00z Mon shows a tendency toward a less negative tilt with the trough axis, and associated more zonal flow at H5. I already don't like low-amplitude waves this early in the season on the Plains, and this is only raising my concerns. In my experience, H85 flow as veered as what the 06/00z GFS shows verbatim along the dryline in OK is nearly a dealbreaker for meaningful tornado potential in this part of the country. For the most part, when you have low-amplitude waves traversing a Plains dryline in the early season, the shortwave timing has to be absolutely impeccable - where you get your LLJ to back and intensify right around 21-00z. If that isn't the case, as is currently modeled Sunday, you either get (1) a cap bust, or (2) if you're fortunate enough to get CI, tornado potential is limited, even if other factors (e.g., good moisture return) are in place. Still time for 6-12 h timing shifts, so not throwing in the towel by any means - just commenting.

Feel free to bump troll this tomorrow, but I really doubt CI will be a problem by 5-6pm. With this kind of compact, neutral/negative tilt shortwave and a generally NNW-SSE dryline, you aren't often going to lack for storms unless moisture is truly nonexistent. This is also a classic setup where the model consensus (and especially the NAM with its convective scheme) is too bearish on CI during the afternoon hours. Junky storms? Very possible, but that's probably the least exciting plausible scenario.

Generally positive trends on the guidance the last 24 h, for what they're worth given the baseline. I'm liking the nudge back toward a negative tilt on this wave, and the (somewhat related) more rapid moisture return Sunday afternoon. Moisture will almost certainly put the event ceiling somewhere below a multi-storm tornado outbreak, but intense supercells with some low-end evening threat are more plausible now.

Tuesday is looking more and more like the best shot to start pulling real moisture up more than 2 hours before showtime - something Sunday is sorely lacking on most of today's runs.