Irrational Exuberance?
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- Tropical Depression
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Irrational Exuberance?
I've seen several forecasters here predicting 6-10" of snow in the NYC area, which I am considered part of, generally (I live ~25 miles SW of NYC and tend to get very similar snowfalls as NYC, since our being a little south is often offset by us being a little more inland; similar, near sea level elevations in both; unlike points that are 25 miles west, NW or N of NYC that get a fair amount more, on average than NYC, due to being further from the ocean and at higher elevation). However, so far the NWS, most of the NYC media outlets and, most importantly for me, Gary Grey, do not agree and have NYC being more in the 2-6" range. See Gary's current (4 pm) map in the link below, which has NYC and my town firmly in the 1-2" range and about 50 miles from the 2-4" range, let alone about 100 miles from the 4-8" swath (AC is exactly 90 miles from my house - I play poker there enough to know that mileage).
http://www.millenniumweather.com/gifs/snowtot.gif
While I hope the much greater amounts fall here, I'm skeptical of such forecasts, especially as I've been following Mr. Grey for about 3 winters now and he has clearly been the best forecaster of snowfall amounts in the NYC area, and as far as I can tell, he looks to be pretty darn good for the northeast, in general, although I don't track forecasts for other areas as closely as I do my area. Now, I'm not a meteorologist, but I do have an advanced degree in chemical engineering, which has many commonalities with meteorology (heat/mass transfer, energy balances, physical chemistry, advanced mathematical models, etc.) and I do follow the weather pretty closely (I may not know how to forecast, but I certainly know how to measure forecast accuracy - it's not hard) and I was wondering what some of the pros think of him. I also know there's no "right" forecast until the weather verifies, but his track record has been excellent.
http://www.millenniumweather.com/gifs/snowtot.gif
While I hope the much greater amounts fall here, I'm skeptical of such forecasts, especially as I've been following Mr. Grey for about 3 winters now and he has clearly been the best forecaster of snowfall amounts in the NYC area, and as far as I can tell, he looks to be pretty darn good for the northeast, in general, although I don't track forecasts for other areas as closely as I do my area. Now, I'm not a meteorologist, but I do have an advanced degree in chemical engineering, which has many commonalities with meteorology (heat/mass transfer, energy balances, physical chemistry, advanced mathematical models, etc.) and I do follow the weather pretty closely (I may not know how to forecast, but I certainly know how to measure forecast accuracy - it's not hard) and I was wondering what some of the pros think of him. I also know there's no "right" forecast until the weather verifies, but his track record has been excellent.
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- S2K Analyst
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Re: Irrational Exuberance?
RU848789,
It should be noted that FLguy is an outstanding forecaster. He nailed the December 5-6 blizzard well before its occurrence.
At this time, there is still much uncertainty with respect to the computer guidance--e.g., the "war of ideas" between the dry GFS and wet ETA. If the ETA proves closer on this event--and it has fared well, lately--given the snow:liquid ratios, 6"-10" could well be realized: e.g., 0.35"-0.50" could translate into the 6"-10" range.
FWIW, at this point, I'm erring on the side of conservatism and favoring 3"-6" for NYC. Even with confluence, I find it somewhat difficult to believe that NYC will substantially less than let's say 3". These ideas are still preliminary and tomorrow's runs should be decisive.
It should be noted that FLguy is an outstanding forecaster. He nailed the December 5-6 blizzard well before its occurrence.
At this time, there is still much uncertainty with respect to the computer guidance--e.g., the "war of ideas" between the dry GFS and wet ETA. If the ETA proves closer on this event--and it has fared well, lately--given the snow:liquid ratios, 6"-10" could well be realized: e.g., 0.35"-0.50" could translate into the 6"-10" range.
FWIW, at this point, I'm erring on the side of conservatism and favoring 3"-6" for NYC. Even with confluence, I find it somewhat difficult to believe that NYC will substantially less than let's say 3". These ideas are still preliminary and tomorrow's runs should be decisive.
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- Tropical Depression
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Bumping this back up to the top for two reasons. One, I'm just curious why it got very little response 2 days ago and why another post I made yesterday similarly talking about Mr. Grey downplaying the first storm in the NYC area (too dry) and the second storm (too warm for snow) got no response at all. Is it because I'm new to the board? Too many people forecasting with their hearts and not their heads (-removed-) and don't want to discuss possibilities of much less snow? People don't like Gary Grey for some reason?
As I said, he's easily been the most accurate in these parts for the 3 years I've been reading him and he appears to be on target so far for the first storm, which he always had C NJ and NYC in the 1-2" and at most 2-4" range. In fact, the NWS in Philly downgraded the first event significantly for Central Jersey, as yesterday's WS watches were forecasting 4-7" of snow, but now we're in a WW Advisory with just 2-4" forecast in Middlesex/Somerset Counties and only 1-2" north of there. Plus, the NYC/Upton office is saying only 1-2" for NYC and only flurries in the NW and NE suburbs of NYC from the first event.
http://www.millenniumweather.com/winter/cast2.html
And, unfortunately, for the Tuesday event, he has the coastal areas of C NJ, NE NJ, NYC and LI as receiving very little snow from the 2nd storm - maybe only a couple of inches - it's a little hard to tell, as he has the whole 2-3 day event on one total snowfall map, but his discussion makes it clear he expects enough warmth to come into these areas to lead to sleet or freezing rain or even just rain. But then again, he also hedges somewhat, saying his confidence is not that high on the 2nd event and it would only take some small changes to bring our areas into the snow region, such that we could still see significant snow from the 2nd impulse.
As much as I've been impressed with his performance, I sure hope he's wrong on both systems this time, as his current forecast leaves me with maybe 2-4" total from both systems, plus some sleet and freezing rain and rain making a messy soup on the sreets. Manhattan gravy.
donsutherland1 - for the record, he also nailed the 12/6 storm this year, as well as last week's two storms, plus last year's Preesident's Day blizzard (and others) which is why I'm posting his predictions here.
As I said, he's easily been the most accurate in these parts for the 3 years I've been reading him and he appears to be on target so far for the first storm, which he always had C NJ and NYC in the 1-2" and at most 2-4" range. In fact, the NWS in Philly downgraded the first event significantly for Central Jersey, as yesterday's WS watches were forecasting 4-7" of snow, but now we're in a WW Advisory with just 2-4" forecast in Middlesex/Somerset Counties and only 1-2" north of there. Plus, the NYC/Upton office is saying only 1-2" for NYC and only flurries in the NW and NE suburbs of NYC from the first event.
http://www.millenniumweather.com/winter/cast2.html
And, unfortunately, for the Tuesday event, he has the coastal areas of C NJ, NE NJ, NYC and LI as receiving very little snow from the 2nd storm - maybe only a couple of inches - it's a little hard to tell, as he has the whole 2-3 day event on one total snowfall map, but his discussion makes it clear he expects enough warmth to come into these areas to lead to sleet or freezing rain or even just rain. But then again, he also hedges somewhat, saying his confidence is not that high on the 2nd event and it would only take some small changes to bring our areas into the snow region, such that we could still see significant snow from the 2nd impulse.
As much as I've been impressed with his performance, I sure hope he's wrong on both systems this time, as his current forecast leaves me with maybe 2-4" total from both systems, plus some sleet and freezing rain and rain making a messy soup on the sreets. Manhattan gravy.
donsutherland1 - for the record, he also nailed the 12/6 storm this year, as well as last week's two storms, plus last year's Preesident's Day blizzard (and others) which is why I'm posting his predictions here.
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- Tropical Storm
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- Scott_inVA
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After the TOR watch went up last night and the convective line formed I began talking about the possibility of convection robbing moisture. Zip, zero, nada comments b/c the mention of anything opposed to big snow is not welcomed by most.
The low tops are now waning given limited instability but dry wedge in KY/TN is already there. I am fascinated by this and eager to see if the wedge makes it into W NC/SW VA ahead of additional moisture transport coming up later this afternoon. If so, folks, we have a decent bust on our hands.
Scott
WREL Radio
Lexington, VA
The low tops are now waning given limited instability but dry wedge in KY/TN is already there. I am fascinated by this and eager to see if the wedge makes it into W NC/SW VA ahead of additional moisture transport coming up later this afternoon. If so, folks, we have a decent bust on our hands.
Scott
WREL Radio
Lexington, VA
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- Chris the Weather Man
- Category 2
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- S2K Analyst
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RU848789,
Several points:
1) I had not intended to criticize GG nor is there any reason for me to dislike GG. In general, I do not criticize those making forecasts, though I might disagree with forecasts from time to time. Informed and knowledgeable people can hold different opinions on various scenarios.
2) With respect to the snow events, I'm still comfortable with 3"-6" total for NYC. Unfortunately, where my error--and yes, it was an error as there was some model guidance for such a situation--was that I assumed the Sunday night-Monday event would provide most or all this snow.
Now, it is increasingly clear that there will be a proverbial tale of two events. Light snow for the first one will be the rule and GG deserves credit on this. A better snowfall for the second should occur. There's still much uncertainty pertaining to the second event.
Nevertheless, I do believe the combined total for the two events will be at least 3"-6" in NYC (probably at least 3"-5" for the second one) but the potential does exist for more depending on the development of the coastal secondary for Tuesday into Wednesday. Eastern New England, including Boston, should see a significant snowfall (more than 6") from this latter system.
3) Please continue to post GG's predictions. Although I read his site daily, others might not, so your providing info. on GG's predictions is quite useful. All said, as far as I'm concerned, the more opinions and analysis offered, the better.
Several points:
1) I had not intended to criticize GG nor is there any reason for me to dislike GG. In general, I do not criticize those making forecasts, though I might disagree with forecasts from time to time. Informed and knowledgeable people can hold different opinions on various scenarios.
2) With respect to the snow events, I'm still comfortable with 3"-6" total for NYC. Unfortunately, where my error--and yes, it was an error as there was some model guidance for such a situation--was that I assumed the Sunday night-Monday event would provide most or all this snow.
Now, it is increasingly clear that there will be a proverbial tale of two events. Light snow for the first one will be the rule and GG deserves credit on this. A better snowfall for the second should occur. There's still much uncertainty pertaining to the second event.
Nevertheless, I do believe the combined total for the two events will be at least 3"-6" in NYC (probably at least 3"-5" for the second one) but the potential does exist for more depending on the development of the coastal secondary for Tuesday into Wednesday. Eastern New England, including Boston, should see a significant snowfall (more than 6") from this latter system.
3) Please continue to post GG's predictions. Although I read his site daily, others might not, so your providing info. on GG's predictions is quite useful. All said, as far as I'm concerned, the more opinions and analysis offered, the better.
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- S2K Analyst
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Chris,
While I believe such an event might occur in February given the evolution of the synoptic pattern and past years with similar patterns, I do not believe NYC will see such a snowfall from the Tuesday into Wednesday event. A reasonable chance does exist for more than 10" but I believe the best snows will probably be further north.
All will depend on the development of the secondary and timing when it becomes the primary system--to pull in sufficient cold air and also provide sufficient QPF. Let's see what later model runs offer.
While I believe such an event might occur in February given the evolution of the synoptic pattern and past years with similar patterns, I do not believe NYC will see such a snowfall from the Tuesday into Wednesday event. A reasonable chance does exist for more than 10" but I believe the best snows will probably be further north.
All will depend on the development of the secondary and timing when it becomes the primary system--to pull in sufficient cold air and also provide sufficient QPF. Let's see what later model runs offer.
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- Tropical Depression
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don - didn't mean to imply that you, specifically, had problems with GG, or his forecasts, just that some folks, in general, might. I was also not referring to you, specifically in my comments about overdoing the snow - without naming people, it just seemed like there were an awful lot of folks predicting large snowfalls for the first event without necessarily reading what the "experts" were saying (which is all I can do, as I'm not a meteorologist - for me it's far easier to track others' performance than to actually put my expertise on the line and perform). Especially when people (not you, at all) simply post that X or Y is going to happen without qualifying such statements with some sort of error bars, as it doesn't take a met to know that these are very complex models that only partially capture the far more complex nature of real weather and that these are dynamic models that depend greatly on the underlying physical principles being properly considered and just as greatly on the simplifying assumptions made and the initialization input data. The old "garbage in, garbage out." I dabble a bit in computational fluid dynamics as it applies to mixing and heat/mass transfer in chemical reactors, and defining systems even on that small of a scale is fraught with model error and bias (although throwing in chemical reactions adds a level of complexity not encountered in the physics and physical chemistry of meteorology - unless you're doing ozone depletion or smog formation) - I can't even imagine how complex these atmospheric models must be. Some day I need to sit down with a meteorologist to learn what these models really entail and how they're used. Maybe it's time to take a course - I'm only 10 minutes from Rutgers (went to school there for 9 years, all through the 80s).
Oh, and the NWS just returned several southern NJ counties to WS Warnings and bumped Middlesex County back to an advisory for 2-4" by tomorrow. Funny thing is Upton still has Union County, 5 miles to my north, as only getting a dusting. Someone didn't cross-check. Plus, issuing forecasts at the county level isn't granular enough - need finer details - I'd prefer they issue maps, like many media outlets and mets on sites like this do - allows for more logical gradation.
P.S. Gary looks to be pretty close on the first event, but if the 2nd system is colder and deeper and we get hammered, he will have been pretty far off, although I give him credit for pointing out how iffy his forecast was, plus it was almost 48 hours out and I'm sure error rates for 48 hour forecasts are pretty big.
Oh, and the NWS just returned several southern NJ counties to WS Warnings and bumped Middlesex County back to an advisory for 2-4" by tomorrow. Funny thing is Upton still has Union County, 5 miles to my north, as only getting a dusting. Someone didn't cross-check. Plus, issuing forecasts at the county level isn't granular enough - need finer details - I'd prefer they issue maps, like many media outlets and mets on sites like this do - allows for more logical gradation.
P.S. Gary looks to be pretty close on the first event, but if the 2nd system is colder and deeper and we get hammered, he will have been pretty far off, although I give him credit for pointing out how iffy his forecast was, plus it was almost 48 hours out and I'm sure error rates for 48 hour forecasts are pretty big.
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- S2K Analyst
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RU848789,
These systems can sometimes be extremely complex. Obviously, the confluence helped limit the northern extent of the snowfall with the system now winding down.
The next storm is also offers much uncertainty. Miller B systems (where a primary system in the TN or OH Valleys transfers energy to a secondary coastal storm) can lead to large forecasting busts. Even the computer guidance can be subject to large errors with such systems.
As <b>noted</b> last night, I believe that some areas could see a significant snowfall tomorrow night into Wednesday.
This morning's model guidance reinforces this idea, which was developed based on not just the computer guidance but a look at some past synoptic setups similar to the current one. So far, to some extent, the models have trended in the direction of a weaker primary system-stronger secondary system.
Consequently, I have growing confidence that the thicknesses will crash as the secondary begins to bomb out and any sleet will change to all snow in NYC, for example, between 8pm and 11 pm tomorrow night, perhaps a little earlier. Also bear in mind that the surface and mid-level readings are running below those forecast yesterday, so this might also mean a somewhat earlier changeover and/or less in the way of sleet relative to snow.
Given some of the latest guidance, some refinements to the early ideas might be in order e.g., if the storm deepens more quickly than anticipated and depending on its location where this happens, a dry slot could be swept across Philadelpia and southern New Jersey. At the same time, amounts from Northern NJ to southern New England might need to be bumped up somewhat.
These systems can sometimes be extremely complex. Obviously, the confluence helped limit the northern extent of the snowfall with the system now winding down.
The next storm is also offers much uncertainty. Miller B systems (where a primary system in the TN or OH Valleys transfers energy to a secondary coastal storm) can lead to large forecasting busts. Even the computer guidance can be subject to large errors with such systems.
As <b>noted</b> last night, I believe that some areas could see a significant snowfall tomorrow night into Wednesday.
This morning's model guidance reinforces this idea, which was developed based on not just the computer guidance but a look at some past synoptic setups similar to the current one. So far, to some extent, the models have trended in the direction of a weaker primary system-stronger secondary system.
Consequently, I have growing confidence that the thicknesses will crash as the secondary begins to bomb out and any sleet will change to all snow in NYC, for example, between 8pm and 11 pm tomorrow night, perhaps a little earlier. Also bear in mind that the surface and mid-level readings are running below those forecast yesterday, so this might also mean a somewhat earlier changeover and/or less in the way of sleet relative to snow.
Given some of the latest guidance, some refinements to the early ideas might be in order e.g., if the storm deepens more quickly than anticipated and depending on its location where this happens, a dry slot could be swept across Philadelpia and southern New Jersey. At the same time, amounts from Northern NJ to southern New England might need to be bumped up somewhat.
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