snowlurker Posted February 15, 2013 Share Posted February 15, 2013 Guys, check the description on those products: http://www.hpc.ncep.noaa.gov/pwpf/about_pwpf_products.shtml They aren't the final probabilities; they are a 28 member "auto ensemble" that includes all 21 sref members, 7 of the latest operational runs (in this case the ECMWF is the prior run), along with the HPC WWD's deterministic snowfall forecast that is sent internally to the WFOs for guidance. The reason why HPC doesn't go public with their deterministic snow/ice accum graphics is because the WFOs (and thus NDFD) have final say on accums and we don't want to add confusion or conflict within NWS products. So, the WFOs (and RFCs) can see that deterministic output from HPC via an internal webpage, usually by 0630 and 1830Z so they can have enough time to use those grids as guidance if they choose to. The deterministic accumulations (which is prism or elevation adjusted) serve as a baseline guidance for the field offices, while also serving as a member along with the 28 member autoensemble probabilistic forecast. Ah, but it is an important lone member in that it serves as the "mode" for those probabilistic calculations that you see linked from the HPC website. The forecaster-adjusted "final" probabilities are manually edited for the 4, 8, 12 inch 10, 40, 70 percent probabilities. They come out between 8-9 and 20-21Z. One other thing about those autoensemble probabilities: 21 of 28 members are the SREF components, i.e. 7 WRF members, 7 NMM members, and 7 NMMB members. In other words: very SREF heavy. So, if the SREF is out to lunch...guess what...so will the autoensemble. These adjustments should show up in the HPC final 4/8/12" probabilities, though we don't edit the 1, 2, or 6" inch probs. Thanks - this is very informative. Link to comment Share on other sites More sharing options...
mitchnick Posted February 15, 2013 Share Posted February 15, 2013 new srefs, fwiw,are unimpressive with only around .25"+ qpf in the DCA/BWI area Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 new srefs, fwiw,are unimpressive with only around .25"+ qpf in the DCA/BWI area Based on 18Z data. Let's clear the deck with 00Z. I think we can sink to new depths of ineptitude. Link to comment Share on other sites More sharing options...
Kmlwx Posted February 15, 2013 Share Posted February 15, 2013 Based on 18Z data. Let's clear the deck with 00Z. I think we can sink to new depths of ineptitude. Let's aim for light rain Link to comment Share on other sites More sharing options...
SlowerLowerDE Posted February 15, 2013 Share Posted February 15, 2013 From Mt Holly at 8:51pm: THE BIG PLAYER IN THE LONGTERM PERIOD IS THE POSSIBLE WINTER STORMSTARTING FRIDAY NIGHT THROUGH A BETTER PART OF THE DAY ON SATURDAY.MID-LEVEL TROUGHING, DEPENDING ON HOW DEEP IT BECOMES, WILL DICTATEHOW FAR OR CLOSE TO THE COAST THE SURFACE WAVE MOVES. SURFACECYCLOGENESIS IS VERY LIKELY TO OCCUR JUST AHEAD OF THE COLD FRONTALPASSAGE FRIDAY EVENING AND MOVES OFF TOWARDS THE NORTHEAST. DID NOTBUY INTO A WHOLE-SALE CHANGE WITH OUR SNOWFALL TOTALS AND USED AMORE CONSERVATIVE APPROACH. LOOKS LIKE A SOLID 2-4 FROM PHILADELPHIASOUTH AND EAST WHICH WOULD PUT THEM CLOSE TO HEADLINECRITERIA...JUST DID NOT HAVE THE CONFIDENCE BASED ON ONE MODEL RUN. It's looking better. Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 NAM has a little burst with the first wave. Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 Burst of rain. Surface is toasty. Link to comment Share on other sites More sharing options...
Quasievil Posted February 15, 2013 Share Posted February 15, 2013 NAM has a little burst with the first wave. Wait... wait... really... oh boy!!! Burst of rain. Surface is toasty. Oh yeah. Reality check. My bad. Link to comment Share on other sites More sharing options...
Bob Chill Posted February 15, 2013 Share Posted February 15, 2013 Burst of rain. Surface is toasty. Kenny nailed it Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 Might be time to shut her down, boys. Link to comment Share on other sites More sharing options...
Quasievil Posted February 15, 2013 Share Posted February 15, 2013 Might be time to shut her down, boys. Honestly, in this 2011-2013 Winturd, why do we keep turning it on? Wonder if we can get any flakes on Saturday afternoon? Link to comment Share on other sites More sharing options...
ravensrule Posted February 15, 2013 Share Posted February 15, 2013 Might be time to shut her down, boys. I will hang in until the NAM ensembles come in, those will save us. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted February 15, 2013 Share Posted February 15, 2013 Might be time to shut her down, boys. Well, shoot...guess our fake punt on this system was foiled! Onside kick attempt for the lakes cutter event next week?? (Edit: Oh, wait, we have to actually score first before attempting an onside kick. Nevermind!!) Link to comment Share on other sites More sharing options...
Amped Posted February 15, 2013 Share Posted February 15, 2013 NAM on instantweathermaps through 35h shows no snow for basically the entire area. Link to comment Share on other sites More sharing options...
Kmlwx Posted February 15, 2013 Share Posted February 15, 2013 Kenny nailed it Seems easy this winter I'm going to maintain that I will be happy to see a little white. Although maybe even that's a stretch. Link to comment Share on other sites More sharing options...
usedtobe Posted February 15, 2013 Share Posted February 15, 2013 Kenny nailed it How much rain, looks quite bit drier through 06Z and that may be why it's so warm. Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 How much rain, looks quite bit drier through 06Z and that may be why it's so warm. I am sorry for doubting you. Link to comment Share on other sites More sharing options...
swimmatte Posted February 15, 2013 Share Posted February 15, 2013 Might be time to shut her down, boys. So we're ignoring the GFS huh? Link to comment Share on other sites More sharing options...
Deck Pic Posted February 15, 2013 Share Posted February 15, 2013 Might be time to shut her down, boys. So much for your cheerleading. Why shut it down now? Maybe the models aren't catching onto a feature that will give us a 20" snow downburst. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 15, 2013 Share Posted February 15, 2013 You really do have to admire the way every possible snow threat gets ripped away from our area. It has it's own kind of awesomeness. Link to comment Share on other sites More sharing options...
PhineasC Posted February 15, 2013 Author Share Posted February 15, 2013 So much for your cheerleading. Why shut it down now? Maybe the models aren't catching onto a feature that will give us a 20" snow downburst. Not sure why you are coming after me. You are one of the most emotional and manic posters here (as shown by your post). Link to comment Share on other sites More sharing options...
sonickteam Posted February 15, 2013 Share Posted February 15, 2013 i just sold my snow shovel on ebay Link to comment Share on other sites More sharing options...
Deck Pic Posted February 15, 2013 Share Posted February 15, 2013 You really do have to admire the way every possible snow threat gets ripped away from our area. It has it's own kind of awesomeness. It was never a snow threat. It was a model threat that the models picked up on 5 minutes ago and people ran away with. Vinyl even came out of retirement to talk about a Hecs. This is going to be the deepest sharpest trough anyone has ever seen in history. Maybe we'll get the usual. Rain, cartopper. 1-2" for Ji. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted February 15, 2013 Share Posted February 15, 2013 So much for your cheerleading. Why shut it down now? Maybe the models aren't catching onto a feature that will give us a 20" snow downburst. I'm holding out hope for the rare snow derecho. Link to comment Share on other sites More sharing options...
NOVAForecaster Posted February 15, 2013 Share Posted February 15, 2013 I knew this would end poorly after we started the thread.... Link to comment Share on other sites More sharing options...
Quasievil Posted February 15, 2013 Share Posted February 15, 2013 I knew this would end poorly after we started the thread.... No more "storm threat" threads. Please. No. Link to comment Share on other sites More sharing options...
Amped Posted February 15, 2013 Share Posted February 15, 2013 Nam did tick west with the surface low and front off of cape cod. Won't help us though. Edit: second batch of fools gold in Central Virgina at 48 hrs Probaly OTS but well west of 18z. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 15, 2013 Share Posted February 15, 2013 It was never a snow threat. It was a model threat that the models picked up on 5 minutes ago and people ran away with. Vinyl even came out of retirement to talk about a Hecs. This is going to be the deepest sharpest trough anyone has ever seen in history. Maybe we'll get the usual. Rain, cartopper. 1-2" for Ji. Well, models are emotionless, so when models put out systems whether they be snow or rain, there's something there that's causing them to do that. Weenies dont cause a model to show snow solutions. For whatever reason, they have a knack of showing us a picture that we want to see, and then retracting it. And this isn't just happening in one or two models, it's across the board. The "cold" light snow we had around the 25th of Jan is a great example. That looked great on everything, especially the beloved Euro, only to wilt and die as we got closer. It seems lately, every event, if you can call them that, goes through the exact same progression. Link to comment Share on other sites More sharing options...
Scarlet Pimpernel Posted February 15, 2013 Share Posted February 15, 2013 It was never a snow threat. It was a model threat that the models picked up on 5 minutes ago and people ran away with. Vinyl even came out of retirement to talk about a Hecs. This is going to be the deepest sharpest trough anyone has ever seen in history. Maybe we'll get the usual. Rain, cartopper. 1-2" for Ji. It is true the "threat" suddenly showed up today. Or, more appropriately, "re-appeared" today. However, the models did indicate a good storm signal around the 18th. There were some weird solutions, yes, but overall it looked like a real possibility in many ways, and I know a lot of the more knowledgeable mets on here were saying the same thing about the overall pattern. Then it more or less evaporated, a sharp trough with the energy farther north (or something like that), which took the thermal gradient too far east. And since then, that's been the predominant solution. Seems that kind of thing has happened every time this year, a good signal and good overall pattern shows up, but nothing pans out. Link to comment Share on other sites More sharing options...
stormtracker Posted February 15, 2013 Share Posted February 15, 2013 Post 45 hour...don't do it. Don't one person in here do it. Fool's gold II. Link to comment Share on other sites More sharing options...
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