RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Its actually the pv that is acting like a 50/50. And because its being somewhat locked in by a weak block over davis straight, its forcing the system more E then N. So really, the flow isnt as progressive as some have stated. BUT, because the pv still has to slide to through se canada still, guidance will adjust some more today into tonight. Honestly we arent THAT far off from a bigger solution. Link to comment Share on other sites More sharing options...
eyewall Posted December 31, 2013 Share Posted December 31, 2013 Game over for BTV on this one and then ptype problems with the cutter next week. Link to comment Share on other sites More sharing options...
shawnmov Posted December 31, 2013 Share Posted December 31, 2013 Any chance this starts ticking west again or does everybody feel this is a done deal now, moderate event. Link to comment Share on other sites More sharing options...
nutmegfriar Posted December 31, 2013 Share Posted December 31, 2013 I find it odd how some here stay up to all hours for days on end following models and then rejoice when storms fizzle or move out to sea. Link to comment Share on other sites More sharing options...
78Blizzard Posted December 31, 2013 Share Posted December 31, 2013 Toaster sales seem to be on the rise this morning........lol. Plowable snow still looks probable. Chances of something more significant decreasing. I saw cars lining up on the Tobin this morning. Link to comment Share on other sites More sharing options...
wx2fish Posted December 31, 2013 Share Posted December 31, 2013 6z ensemble individual members look pretty decent. Most are a solid moderate event for SNE with a couple fairly amped members. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 Could someone explain this? I hate these probability maps. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Any chance this starts ticking west again or does everybody feel this is a done deal now, moderate event. Not a done deal but this also can escape further E too. Link to comment Share on other sites More sharing options...
snowman21 Posted December 31, 2013 Share Posted December 31, 2013 Could someone explain this? I hate these probability maps. BDL has a 90% chance of at least a 2-4 inch snowfall, an 80% chance of 4-8 inches, and 60% chance of 8-12. Usually you don't use ranges, just probability of exceeding thresholds (i.e. the probability of getting at least 4 inches, at least 8 inches, and so forth like the SREF snowfall probability maps). Link to comment Share on other sites More sharing options...
dabize Posted December 31, 2013 Share Posted December 31, 2013 DT thinks most of us are getting crushed, apparently Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Could someone explain this? I hate these probability maps. U have a 90% chance at 2-4" and a 40% chance at 12-16". So there is still hope for your front porch. Link to comment Share on other sites More sharing options...
moneypitmike Posted December 31, 2013 Share Posted December 31, 2013 Lesson learned for stations who had offered high accumulation ideas yesterday?? Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 U have a 90% chance at 2-4" and a 40% chance at 12-16". So there is still hope for your front porch. Whoever developed these probability ideas made it far more confusing than it needs to be. Just put one map out with what your forecast is Link to comment Share on other sites More sharing options...
moneypitmike Posted December 31, 2013 Share Posted December 31, 2013 U have a 90% chance at 2-4" and a 40% chance at 12-16". So there is still hope for your front porch. Has me with 90% for 2". At least my brown would be white again. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Lesson learned for stations who had offered high accumulation ideas yesterday?? If They haven't learned already, they never will. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Frankly, probability maps should be used across the board instead of snowfall forecast maps. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 Frankly, probability maps should be used across the board instead of snowfall forecast maps. Violently disagree. Vehemently Link to comment Share on other sites More sharing options...
powderfreak Posted December 31, 2013 Share Posted December 31, 2013 Frankly, probability maps should be used across the board instead of snowfall forecast maps. Yeah...much easier way to convey confidence levels in snowfall amounts through probability. Link to comment Share on other sites More sharing options...
snowman21 Posted December 31, 2013 Share Posted December 31, 2013 Whoever developed these probability ideas made it far more confusing than it needs to be. Just put one map out with what your forecast is The probability based forecasts make it easier to accurately gauge forecast skill. If you just go by hard ranges, then you're either right or wrong, and your forecast skill is either 0% or 100%. If you say BDL has a 50% chance of reaching 6 or more inches, then you're going to be half right or wrong depending on whether 5.5 or 6.5 inches falls. The math in the skill scores is slightly more complicated than that, but that's the general idea behind them. Also when you consider forecast models that run let's say 50 simulations every time, you will get some distribution of forecasts (a range of predicted high temperatures, for example, with some outliers and then a tighter cluster in the middle), and probability is another way to express the composite model output. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Violently disagree. Vehemently Of course you do. you see it from just your perspective as usual. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 Of course you do. you see it from just your perspective as usual. Doesn't everyone see things from their own perspective? Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 The probability based forecasts make it easier to accurately gauge forecast skill. If you just go by hard ranges, then you're either right or wrong, and your forecast skill is either 0% or 100%. If you say BDL has a 50% chance of reaching 6 or more inches, then you're going to be half right or wrong depending on whether 5.5 or 6.5 inches falls. The math in the skill scores is slightly more complicated than that, but that's the general idea behind them. Also when you consider forecast models that run let's say 50 simulations every time, you will get some distribution of forecasts (a range of predicted high temperatures, for example, with some outliers and then a tighter cluster in the middle), and probability is another way to express the composite model output. It seems to me though that is the easy way out. It means you can never be wrong. To me anyway..it's kind of a way of saying..i really don't know how much we're going to get.. Link to comment Share on other sites More sharing options...
nutmegfriar Posted December 31, 2013 Share Posted December 31, 2013 Violently disagree. Vehemently Agree with you. DT's map shows a 90% chance of having an 80% chance of 2 inches. Seems a bit much for this layman. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted December 31, 2013 Share Posted December 31, 2013 Its actually the pv that is acting like a 50/50. And because its being somewhat locked in by a weak block over davis straight, its forcing the system more E then N. So really, the flow isnt as progressive as some have stated. BUT, because the pv still has to slide to through se canada still, guidance will adjust some more today into tonight. Honestly we arent THAT far off from a bigger solution. There is also an upstream kicker that's beating down the riding out W. Still looks good for the SE MA/ CC areas. Nasty couple days with the cold, wind, and snow. May not meet the "blizzard" criteria due to lower winds but visibilities will be low, Link to comment Share on other sites More sharing options...
CoastalWx Posted December 31, 2013 Share Posted December 31, 2013 Yeah to me it's upstream that is more the issue. Without the PV this thing is over our fannies. Hopefully things tick north today. 06z looked decent to me. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 There is also an upstream kicker that's beating down the riding out W. Still looks good for the SE MA/ CC areas. Nasty couple days with the cold, wind, and snow. May not meet the "blizzard" criteria due to lower winds but visibilities will be low, Good note about the kicker I didn't see that tbh. Link to comment Share on other sites More sharing options...
Damage In Tolland Posted December 31, 2013 Share Posted December 31, 2013 If you just see it that way good luck in life. I have a great life. How about you? Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 31, 2013 Share Posted December 31, 2013 Yeah to me it's upstream that is more the issue. Without the PV this thing is over our fannies. Hopefully things tick north today. 06z looked decent to me. A little more Northeast PV back to weenie probabilities? Link to comment Share on other sites More sharing options...
40/70 Benchmark Posted December 31, 2013 Share Posted December 31, 2013 Change the thread title. Big snow threat is gone. Moderate snow threat looks good. Should be a nice bitter cold, protracted 7" over 36 hours, with manageable .5"/hr rates in heavier bursts. Can't wait to discuss oes contribution prospects for my favorite beach in Duxbury. Link to comment Share on other sites More sharing options...
snowman21 Posted December 31, 2013 Share Posted December 31, 2013 It seems to me though that is the easy way out. It means you can never be wrong. To me anyway..it's kind of a way of saying..i really don't know how much we're going to get.. You're right in that it allows the forecaster to hedge a bit, but if you don't use probabilities scoring forecast skill becomes dependent on where you set arbitrary discrete break points on a continuous scale. For example, I could always just say the snowfall forecast for BDL is 0-12 inches and I would pretty much have a perfect forecast every time there is a storm. What if I'm the forecaster that refuses to use something other than 3 inch ranges, but there is high spatial variability such that you can't use 3-6, 6-9, 9-12, and so on without being wrong? Then what? Just keep on widening your ranges? Or try to pin down every last town's exact snowfall? That's not realistic or practical. A probabilistic forecast avoids all of that nonsense. If you want to translate a probabilistic forecast into the traditional one you're used to seeing, take the thresholds from say 75 down to 40% and that's your range. If a probabilistic forecast has 20% of reaching 12 inches, 40% of reaching 8 inches, 60% of reaching 6 inches, 80% of reaching 4 inches, and 100% of reaching 2 inches, your forecast range would be 4-8 inches as a rough way to translate between the two types of forecasts. Using a probabilistic forecast by the way implies that you're wrong at least a little most of the time, so it's hardly a way to say you're never wrong as a forecaster. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.