LordBaltimore

fresh, powdery snow has the highest albedo of any surface. Light gets almost completely scattered. Ice and sleet are a bit more translucent if you look at them closely

ice has a slightly lower albedo than snow. I don't believe slight variations in albedo based on snowpack quality are something most models handle, it's usually snow-covered/not snow-covered

I'd imagine besides the depth of freezing layer there's also variability based on if the drops contain ice nucleating particles which then becomes a matter of if they were homogenously nucleated in the first place. Probably no way to tell

somewhere out there the gortons fisherman is about to get his dinghy stuck on a sandbar, covered in freezing spray, blasted by a winter storm, and then capsized by gale force winds

Could see the draw if you're holed up inside. But if I remember right from college there is literally nothing worse than underdressing for a jebwalk stoned

I'm coming around to this event. It's not a big dawg. It's not a cold powder blizzard. But it is a good old fashioned deep winter beat down. Even the best 15+ ratio storms get depressing the next day when they compact. This nasty, sleet hardened mf will be looking the same on Feb 5th that it does early Monday morning just with some extra soot and maybe a few more snowfalls on top

I'm telling you guys, the bay *will* freeze up this year. Maybe not 1977 style but as close as we can get with modern climo. Get ready for bay bridge ice-jam pics Best part is when that happens places near the coast will decouple from their normal water moderated lows

fortran has to be the single most underrated language of all time. It's the perfect mix of low-level enough to do resource management and easy enough to not require someone who is purely a software engineer. And I say this as someone who grew up with python, matlab and c++ lol

I'm exaggerating a little. Obv the model is important, but DA is more important. It was a stupid idea to take on a DA system written in c++ and coded mainly by people outside the field. Most people in this profession are old, they aren't going to learn that shit. And it was effort and money that could've just gone into adding more ensemble members or doing an ensemble of 4dvars like the Euro. But they had to have the shiny object oriented gamer software

The GFS isn't really even a shit model. The model itself is the least important part of prediction. The problem is that years ago everyone decided to take some French guys hair-brained idea and adopt what's unfortunately known as "JEDI" which has become an absolute black hole for man-hours and resources that would otherwise be spent tuning and incrementally improving

2-4 inches of sleet guy knew what's up

Warming up my 6mg wintergreen velo's for the 00Z GFS. Will pair nicely with my gas station disposable mango flavored vape

when I was at UMD for grad school we'd have weekly department meetings and sometimes Louis Uccellini - or as I call him - Louis Uccellini - would show up. I gave a research update one time and he told me, and I quote, "good job"

For the cold outbreak following the storm, at least on the GFS I've noticed a consistent pattern where the VA and even NC piedmont gets sub-zero lows and we're stuck in the single digits. This isn't elevation dependent since it's placing them in low elevation areas to the south and snowpack is high everywhere. Instead it looks like it's because of low-level winds that are calm down south but present at 925mb above Maryland. I've seen this same thing in forecasts after snow events last year and I still can't understand the dynamical reason for it. Is Emporia VA and thereabouts really a better place for vodka cold following a storm pass than MD?

This would be in PREPBUFR no? I'm almost bored enough to check

Anyone know if other models are getting extra data sampling the baja low or just GFS? Sometimes good observations outweigh model accuracy and I'm unsure if this is something that would require knobs to be turned at other met centers who probably don't care as much about a CONUS event

I'd rather have no snow at all than a 10" Noreaster. There's a curve where below 2" of snow sucks for obvious reasons, 2-4" is nice scenery, but then there's really no difference above that until you get to the big dawgs. It's all the world of difference getting 10" vs 18"+

SST's on the bay are already pretty cold from December, and depending on how cold the 1"+ QPF that falls on it is it should start icing up quicker than people would think

RIP anyone who lives in North Carolina. That would be total infrastructure destruction

The names people call models in casual discussion is sort of confusing. The CMC is the GEM model, run by the CMC (met center). Hence RGEM is regional GEM. Similarly the ECMWF isn't really the ECMWF, it's the IFS run by the ECMWF AKA the Euro Center for medium range weather forecasting

our goat is washed :(

The PNA dipping and trough persisting is more or less a tautology. If the models end up spitting out a new solution w/o trough by definition the PNA will not dip further negative.

HRRR and similar CAM's are literally the one thing we do better than the Europeans.

Surprised I haven't seen much if any mention of this lurking around the forums. As everyone knows NoVa and specifically Ashburn, VA is *the* hub of the AI data center boom going on right now. And as everyone also knows, data centers use a ton of water and electricity - most of which ultimately ends up in the atmosphere as waste heat and water vapor. Thinking about this from an urban heat island perspective, you could chalk it up as typical development in an area that's been sprawling for decades, except you'd be way off on scale. These things are unprecedented in terms of energy and water throughput density, they compare absolutely none to any other type of development we've seen before ever and I highly suspect if people looked closely we'd already see some unique effects on regional climate that will continue to grow as more of these things come online in a very concentrated area. How do data centers compare to other sources of UHI? Scale - around 6 GW of capacity used for existing data centers in Loudon county alone, future plans might require upwards of 20. Roughly 2 billion gallons water consumption. Total VA build out, most of which is in NoVA would consume 66 to 100 TWH per year, which is comparable to the state of Tennessee. This isn't normal sprawl. It is the energy usage of entire states, concentrated into waste heat and moisture in a few square miles. It dwarfs the energy consumption of DC proper. The water usage otoh is about 5% of what DC consumes - not off the scale - but consider how it's used. Interaction w/ Environment - New build data centers tend to be built using closed-loop cooling systems, featuring roof-top cooling towers that use airflow + evaporation to chill an internally circulated coolant. I can't find an actual source, but chat GPT suggests that roughly 80% of the waste heat handled by these systems is offset by latent cooling, with about 20% remaining in sensible heat to the atmosphere. All of that water is for the most part being output to the atmosphere rather than being flushed to the bay like most urban water supply - so that 5% figure is actually quite significant. And since these cooling towers are quite low/not that hot, unlike the direct cooling towers on power plants, the moisture output is all going into the PBL rather than the free atmosphere. Long story short, gigawatts and gigawatts of energy is being used to humidify the lower atmosphere in NoVA. It's important to note that this waste heat and humidity is being output in a suburban area, so it will express itself in unfamiliar ways compared to traditional urban UHI. From most studies I've seen, daytime urban UHI is primarily SW albedo + transpiration effects, whereas nightime UHI is attributed to radiative inefficiency (urban canyon + higher heat capacity of surfaces) and waste heat from buildings and vehicles. The night-time effects notoriously combine in various ways, and so for waste heat in a suburban areas you may not see the dramatic increase in over-night minimums that are usually the hallmark of UHI, since there aren't the same kinds of surfaces to trap spatially and temporally varying fluxes of waste heat and dispense them out evenly over the AM hours, and the fluxes from data centers are not as uniform in the first place as cars and buildings that ring every block of a city. Questions Do observations so far indicate anything odd around NoVA? Temperature wise, but also dewpoints How widespread would any effects be? Would it be hyper-local within NoVA or would we get significant downstream transport? If the waste heat and moisture output of data centers is significant, will it express itself in changes to regional convective season climo? This seems reasonable since PBL moisture distribution is a huge factor I plan to dive through the data at some point and post updates, but right now I thought I'd get some input to make sure it's not crazy Here are some articles on NoVA data centers and their electricity/water usage: https://www.businessinsider.com/virginia-data-center-construction-boom-amazon-2025-10 https://www.visualcapitalist.com/map-network-powering-us-data-centers/ https://www.itbrew.com/stories/2024/08/26/northern-virginia-s-data-center-alley-is-thirstier-than-ever

If a Miller A with 30" streaks happens and pier 32 isn't playing in the background then is it even really a big dog?