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.

The 500 mb pattern progged over the next two weeks right now is nothing short of insane, especially by the standard of recent years. Nonstop intense shortwaves dropping into the Rockies and carving across the central CONUS, one after another, with no end in sight. It's been at least since 2011 since we saw a similar pattern in the springtime, and maybe 2008 for the Plains. Really, the first half of May 2003 is what comes to mind, looking at this morning's GFS. It's just happening 30-45 days too early to take full advantage with these short wavelengths, from a severe perspective. But we'll probably get our first headline-making tornado event of the year (outside the Gulf coast) out of this period somehow, regardless.

I don't think I've ever seen one of these quick hitting, compact shortwaves pan out in the Plains early in the spring, but that doesn't mean it can't happen. Last night's GFS and Euro both raise an eyebrow for Sunday. I will say that, as currently progged, I wouldn't be especially worried about mixing as a main failure mode. Rapid cyclogenesis and strong moist advection in the final 12-24 h should minimize the impact there. I think it's more an issue of shortwave timing and whether we can actually pull the preexisting juice to our south up in time.

Bleh. Everything out through D+10 looks like the wavelengths are too short for anything big. Nothing unusual this early, but it sure has been awhile since we saw a half decent March setup in the southern Plains (3/18/12, perhaps?). At least there are some indications of a continued favorable base state heading into the beginning of April.

As Tyler mentioned, we have clickable soundings available on pivotalweather.com. To my knowledge, we're the only site offering this for the HRRR or the 4-km NAM CONUS nest. The load times for GFS and NAM soundings should also be as fast or faster than comparable sites (under 4 sec. in most cases). On our Skew-T Log-P panel, you can find dew point (heavy green line) and wet bulb temp (light blue line). We use SHARPpy for the sounding graphics, which features numerous panels that can be swapped out in the code. Note that while there is a lot of information pertinent to severe weather, we have a simple algorithm that determines whether a sounding profile is "wintry" and will automatically swap out some of that in favor of info like Precip Type, snow growth efficiency, etc. That information is found at the bottom right of the sounding image. If you have any questions or comments/requests, feel free to PM me here!

Another quality tornado (and awesome structure to boot) just E of OMA this afternoon in a MRGL risk with no tornado probs. 2016...

No doubt. Once again, as with every year after 2010 so far, a significantly flawed Plains chase season with a few nice bright spots. The good, well-rounded year with a few obvious big days and several more localized gems still eludes us. I will say, thanks to late May, that it was at least a decent chase season (for everyone who made it out that week). That's more than can be said for the overall severe weather season across the country.

lol and right on cue, our last hope for the season S of I-80 has taken a dive since I last posted. Wave mistimed for good Plains action, and also flattening out more on recent guidance. Tomorrow is pretty marginal, and this morning's CAMs are not optimistic at all, but I'm still considering giving it a shot along the CO/KS border (if not farther W... sigh). Otherwise, my first chaseless June will be quite possible. Tuesday is similarly lukewarm for IA/MO. On the plus side, at least the medium range progs have stopped giving us false hope? That's about the best that can be said for the past 2 weeks.

Last night's Euro looked awfully impressive for KS on Tuesday. Nice surprise that's popped up over the last couple days after it had become easy to assume we were done S of I-80 for the year. Given how well the late May setups performed aided by excellent ET/near surface moisture on the High Plains, I'm already excited about the possibilities for this one, even if some details are less than optimal.

Seems like something respectable almost has to come out of Sun and/or Mon, regardless of whether get a MDT/HIGH caliber day. The biggest question in my mind is whether the Tue-Thu period will offer a second round of potential. The ECMWF tonight changed the North American H5 pattern considerably after the first shortwave ejection, so that's really up in the air. Definitely concerned about this becoming more of an anafrontal flow/shear situation after Sunday, along with the relatively weak anvil level flow over much of the Plains during the whole period. As much as I love just seeing persistent SW flow over rich ET-enhanced moisture in late May, the ECMWF tries to throw every wrench it can into that formula; it also hints at morning convection as a potential problem both Sunday and Tuesday. One would have to think the southern High Plains still hold mesoscale potential several days in almost any scenario, at least. I don't disagree with you, though. From an enthusiast's standpoint looking for a big outbreak to track, things aren't great, and the clock is really ticking climatologically if next week falls flat. From a chaser's standpoint, I still feel pretty good about next week, with the understanding that late May 2004/2008 is probably out of reach. But it can be a fine line between quality late season mesoscale setups vs. just grasping at straws, admittedly.

Euro does look pretty impressive Sun-Tue timeframe. We're finally late enough in the spring that suboptimal timing of shortwave ejections usually won't completely hose a setup, but instead can take a potential outbreak and spread it thinner into multiple localized days - this is the primary reason I enjoy late season chasing about 50x more than March and April, when everything usually has to line up perfectly. Moisture quality for Sun-Mon looks slightly shady on the Euro, while the GFS has been more gung-ho about flooding the Plains with tropical moisture in the medium range. I'm cautiously optimistic that the Euro will trend upward, based on experience. The pattern depicted for the Sun-Wed timeframe isn't anything spectacular - sort of reminiscent of some late season periods in 2013 (May 27-29) and 2014 (early June?) - but the key difference here will be ET, and the likelihood of much better low level moisture than those years ever saw on the High Plains. With quality BL moisture throughout the warm sector in late May, it just doesn't take much at all. I'd be pretty excited for this period as a chasecationer. It would be awesome if something like Bowdle fell out of this pattern, which seems possible - but as long as the trough ejects into the Plains, which looks increasingly likely, a string of localized tornado days should be on tap, for sure. Finding the best storms may not be trivial, but it's hard to beat several consecutive days with hope and opportunity. I'm keeping expectations for any big synoptically-evident days low, given the uncertainties about downstream blocking. But taking the 17/12z Euro verbatim says Monday could actually be that kind of day.