OceanStWx
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Everything posted by OceanStWx
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RAP says you're snowing in 1 hour 30 minutes...
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Schroeter. Those maps are sneaky, because they're going to lump sleet in and make it look like snow. I personally am less bullish but I'm not going to micromanage someone's forecast and warnings are already up for generally awful weather during the commute.
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I'm leaning closer to 10:1 for the meat of it.
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Mind you I hate the P&C wording, but I could see someone pulling 20s. That banding could support 1+ an hour for much of the event. Probably the only limiting factor is that I'm not sure we're going to have the fluffiest ratios.
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Less than 1/4SM vis here at GYX... ...with fog.
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I'm expecting not much more than 1-3" and much of that could be sleet. But I may drive into a pounding snow on my way to GYX tomorrow morning. ALB is nearly due east of the radar. A hair north if getting technical. But it's south of the melting layer for sure.
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No CC on the regional radar, but you can see the change in reflectivity subtly marking the mixing aloft. This line would push north some in Maine as the WAA increases later tonight, but it will be pretty fixed where I drew the line.
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The way I would play it right now is take a look at regional radar. The correlation coefficient is showing up nicely with a flattened NW edge at BGM and ENX, showing the mid level melting layer. According to model forecasts those should be a relatively straight line. I would draw that line through Maine and south of that is where you're looking at the most sleet/freezing rain. Models don't really budge that front aloft until that low slips out towards the Cape.
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HRRR has a temp of 41 and NW winds at ALB at 21z. It's currently 41 with NW winds at 2043z. Tossed.
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And this is kind of anafrontal (for the frozen stuff) and flash freeze.
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Actually love how the NAM sharpens the gradient with time. That's a trend I can believe in. Whether it's in the right location is a different story.
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Scooter below freezing before Kevin.
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If I had full control of the forecast today I would not be congratulating Dendrite. I would bring the sleet up that far for a time. There an old rule of thumb that the heaviest snow is along the 850 mb -4C isotherm. That is pretty consistently around a LEB-Skowhegan line.
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I think it will be, but it isn't going to go from double digits to zero. More like this relatively wide swatch of 2-4 types stuff with a lot of sleet contribution before you jump into the big totals. But given how stable the forcing is aloft, just north of the mid level front is going to pound town.
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It probably will be too. The forcing is intense but incredibly stable in location. Whoever gets under it will be several hours of 1"+/hr. I think most model sites are going to include sleet as snowfall because it is frozen. So naturally Kuchera or 10:1 will be way too high. Pivotal tries to separate out sleet and so the gradient is sharp but not quite as extreme.
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The only thing I know for sure is that the NAM 3km does incorporate a riming factor when outputting snow. Not quite explicit pytpe forecast, but close to it.
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Not sure what their definition of shallow is, because this cold may not be that shallow, but I'm most concerned with the underestimating warm layers aloft. Because what makes the GFS appealing right now is not the surface cold (all guidance more or less gets most of the area below freezing), it's the barely kissing freezing aloft that could support snow. Right now I'm leaning that the barely snow supporting soundings are more figment than fact.
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Model Eval Group just gave a presentation on the GFS and the gist... I was on a separate call about a new road surface temp forecast tool, but I plan to dig into this Fri/Sat when they post the recording. Seems like the new GFS has some predictable biases still.
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Wouldn't shock me if the low level cold is faster than modeled, especially if it can wrap "around" the mountains and surge down the coast. That amount of sleet will be a mess. Hard to melt that even with "warm" roads too.
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Well "we" is New Hampshire not North Haven. That far south, most likely you see a little ice a little sleet. Probably not enough of either to be screwed.
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NAM is nearly 1 inch QPF just sleet. Average ratio is about 2:1, so a half inch of sleet is quite a bit.
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I think that's the highest confidence part of the forecast. Things really go to shit in the morning.
