eduggs Posted December 12, 2013 Share Posted December 12, 2013 Still some concerns for ENY and WMA about being between storms. Best lift initially to the SW and then transferring to the SE. This has frequently been the case in recent years. Best case: 30 hours of light snow beginning Sat morning, ending midday Sun. High fluff factor with occasional moderate intensity. Snowfall 8"+ Worse case: initial overrunning underperforms and is eaten by dry air. Fluff factor not utilized. Accumulating snow stays to the south and west until evening and quickly slides east. Coastal tracks too far SE for any impact and everything to the west quickly dries up. Snowfall 1-3" Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted December 12, 2013 Share Posted December 12, 2013 HPC current SLP is over BM, fwiw. Link to comment Share on other sites More sharing options...
powderfreak Posted December 12, 2013 Share Posted December 12, 2013 Lol...kuchera standard 10:1. Well then something is wrong because that map approaches 10" on the GFS and I'll tell you it doesn't come close to an inch of QPF. Link to comment Share on other sites More sharing options...
RobbieL241 Posted December 12, 2013 Share Posted December 12, 2013 HPC current SLP is over BM, fwiw. 9jhwbg_conus.gif That's still NW from where they had it yesterday I think. Link to comment Share on other sites More sharing options...
Brian5671 Posted December 12, 2013 Share Posted December 12, 2013 I actually think it's trended much better for you in fairfield.. never was looking like more than a few inches at the sw ct shore.. now i think 4-6" down there is a really good bet.. even the city.. We tend to do ok in these setups...granted we'll have sleet or even rain at the end, but by the time that comes, the storm is 80-90% over Link to comment Share on other sites More sharing options...
CoastalWx Posted December 12, 2013 Share Posted December 12, 2013 Well we are still 3 days out. I don't think the track is sold quite yet. Still may drift SE a bit. Link to comment Share on other sites More sharing options...
bobbutts Posted December 12, 2013 Share Posted December 12, 2013 Well then something is wrong because that map approaches 10" on the GFS and I'll tell you it doesn't come close to an inch of QPF. I did the kuchura algorithm map for NAM, the GFS just says Accumulated snow, I am not sure how it's calculated, but there is another separate link 10:1 so I suspect there is more to the one I posted. edit: looks like that one is kuchura too. Contact: Evan Kuchera0.5 degree isobaric GFS GRIB data from NCEP. The snowfall accumulation algorithm used on these charts is as follows: 1) Find the maximum temperature in the lowest 500 hPa in degrees K (MAXTMP) 2) If MAXTMP is greater than 271.16K, then the liquid equivalent ratio (RATIO) is 12.0 + 2.0*(271.16-MAXTMP) 3) If MAXTMP is less than 271.16K, then the liquid equivalent ratio (RATIO) is 12.0 + (271.16-MAXTMP) The 3-hourly snowfall (SNOW) is RATIO multiplied by the three hour liquid precipitation total. The accumulated snowfall (ACCUM_SNOW) is the sum of all the SNOW values up to that projection time. Link to comment Share on other sites More sharing options...
RUNNAWAYICEBERG Posted December 12, 2013 Share Posted December 12, 2013 I don't think they look all that bad right now. Thats what it seems most of pros are saying. Just curious if its slightly warm thermal profile bias is in play. Link to comment Share on other sites More sharing options...
weathafella Posted December 12, 2013 Share Posted December 12, 2013 Yeah that's the thing folks need to get I their heads. Most of the qpf for the majority will be the snow on the front end. By the time mids warm , rates start to slow drastically. Link to comment Share on other sites More sharing options...
Sn0waddict Posted December 12, 2013 Share Posted December 12, 2013 wow! on second thought.. looking at the gfs extractions.. the surface torches quick for the shore. 26 at onset of precip for BDR. by 18z its 31 degrees after .24" QPF. but by 00z sunday its already 42 degrees? Have a hard time believing it gets that warm that quick. I would be shocked if we got that warm. We will hit above 32 but this airmass is very strong and I just don't see it budging so easily. It's going to be impressive to see a temp gradient of up to 20F from S-N though. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted December 12, 2013 Share Posted December 12, 2013 WPC 12z Model Discussion. http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdhmd Link to comment Share on other sites More sharing options...
eduggs Posted December 12, 2013 Share Posted December 12, 2013 Well then something is wrong because that map approaches 10" on the GFS and I'll tell you it doesn't come close to an inch of QPF. I think it includes a tenth or two from lake enhanced snow showers up north. But you're right, that would still be well below 1". It looks more like a hi res version of the GFS, which would account for terrain and arctic frontal lake enhanced snow preceeding the weekend event. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted December 12, 2013 Share Posted December 12, 2013 Well we are still 3 days out. I don't think the track is sold quite yet. Still may drift SE a bit. ya don't say? Link to comment Share on other sites More sharing options...
Radders Posted December 12, 2013 Share Posted December 12, 2013 Still some concerns for ENY and WMA about being between storms. Best lift initially to the SW and then transferring to the SE. This has frequently been the case in recent years. Best case: 30 hours of light snow beginning Sat morning, ending midday Sun. High fluff factor with occasional moderate intensity. Snowfall 8"+ Worse case: initial overrunning underperforms and is eaten by dry air. Fluff factor not utilized. Accumulating snow stays to the south and west until evening and quickly slides east. Coastal tracks too far SE for any impact and everything to the west quickly dries up. Snowfall 1-3" Agree on this post, definitely could go either way in ENY.. Link to comment Share on other sites More sharing options...
heavy_wx Posted December 12, 2013 Share Posted December 12, 2013 Still some concerns for ENY and WMA about being between storms. Best lift initially to the SW and then transferring to the SE. This has frequently been the case in recent years. Best case: 30 hours of light snow beginning Sat morning, ending midday Sun. High fluff factor with occasional moderate intensity. Snowfall 8"+ Worse case: initial overrunning underperforms and is eaten by dry air. Fluff factor not utilized. Accumulating snow stays to the south and west until evening and quickly slides east. Coastal tracks too far SE for any impact and everything to the west quickly dries up. Snowfall 1-3" Dry air doesn't seem to be much of a problem with a decent period of isentropic lift well ahead of the main storm. That should saturate the column pretty well and the 12z GFS shows the sounding near ALB getting saturated all the way up to 250 mb by 12z Saturday. It also has a large area near around -12C which would be very favorable for dendritic snow growth given the lift that will be present. I think 3" is probably on the low end for that area right now; the CIPS analogs as well have been keying in on a snowfall of around 6" for ENY. Link to comment Share on other sites More sharing options...
eduggs Posted December 12, 2013 Share Posted December 12, 2013 Well we are still 3 days out. I don't think the track is sold quite yet. Still may drift SE a bit. As modeled we are about 42 hours from snow arrival and 58 hours from when the coastal is east of the NJ coast. I agree there is still plenty of time to shift. Link to comment Share on other sites More sharing options...
weatherwiz Posted December 12, 2013 Share Posted December 12, 2013 Current thinking Obviously have to probably fine tune this once we have a much more clear idea of where the heaviest totals will reside. While no strong banding signals, there is an impressive burst of really strong VV's which traverse the region which should yield to some impressive rates for a brief period. Link to comment Share on other sites More sharing options...
Stash Posted December 12, 2013 Share Posted December 12, 2013 I certainly understand your concerns and it is possible. I'd actually be a bit more concerned if the secondary was stronger/bombing out that far SE of us. Still some concerns for ENY and WMA about being between storms. Best lift initially to the SW and then transferring to the SE. This has frequently been the case in recent years. Best case: 30 hours of light snow beginning Sat morning, ending midday Sun. High fluff factor with occasional moderate intensity. Snowfall 8"+ Worse case: initial overrunning underperforms and is eaten by dry air. Fluff factor not utilized. Accumulating snow stays to the south and west until evening and quickly slides east. Coastal tracks too far SE for any impact and everything to the west quickly dries up. Snowfall 1-3" Link to comment Share on other sites More sharing options...
moneypitmike Posted December 12, 2013 Share Posted December 12, 2013 I'll bite NAM: GFS: I'll take my 12-15 on the GFS, please. Still some concerns for ENY and WMA about being between storms. Best lift initially to the SW and then transferring to the SE. This has frequently been the case in recent years. Best case: 30 hours of light snow beginning Sat morning, ending midday Sun. High fluff factor with occasional moderate intensity. Snowfall 8"+ Worse case: initial overrunning underperforms and is eaten by dry air. Fluff factor not utilized. Accumulating snow stays to the south and west until evening and quickly slides east. Coastal tracks too far SE for any impact and everything to the west quickly dries up. Snowfall 1-3" Yeah--the qpf demons raring their heads. Link to comment Share on other sites More sharing options...
Clinch Leatherwood Posted December 12, 2013 Share Posted December 12, 2013 Well we are still 3 days out. I don't think the track is sold quite yet. Still may drift SE a bit. That was a pretty significant change in the mid levels on the euro. Hpc is still tracking it over the bm. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 12, 2013 Share Posted December 12, 2013 I'll take this, based on the 60 hour GFS forecast. Link to comment Share on other sites More sharing options...
SnowMan Posted December 12, 2013 Share Posted December 12, 2013 Current thinking Obviously have to probably fine tune this once we have a much more clear idea of where the heaviest totals will reside. While no strong banding signals, there is an impressive burst of really strong VV's which traverse the region which should yield to some impressive rates for a brief period. Interesting. I would have thought more from outside of 495 up into SNH and ME Link to comment Share on other sites More sharing options...
Radders Posted December 12, 2013 Share Posted December 12, 2013 Dry air doesn't seem to be much of a problem with a decent period of isentropic lift well ahead of the main storm. That should saturate the column pretty well and the 12z GFS shows the sounding near ALB getting saturated all the way up to 250 mb by 12z Saturday. It also has a large area near around -12C which would be very favorable for dendritic snow growth given the lift that will be present. I think 3" is probably on the low end for that area right now; the CIPS analogs as well have been keying in on a snowfall of around 6" for ENY. Novice question - How would you look for good lift in the model output to determine this? Relative humidity and Vertical Velocity? Link to comment Share on other sites More sharing options...
NEK_VT_Upslope_Event Posted December 12, 2013 Share Posted December 12, 2013 I'll take this, based on the 60 hour GFS forecast. These guys must've never learned about shadowing... Link to comment Share on other sites More sharing options...
weatherwiz Posted December 12, 2013 Share Posted December 12, 2013 Interesting. I would have thought more from outside of 495 up into SNH and ME Certainly plausible but right now it's not really sold on the exact track of the sfc low and given how there is still room for this to slide back further SE I didn't want to bite on anything higher up there...yet. Typically I would also wait until 0z tonight or 12z tomorrow to make a map but I have a Chem II final tomorrow then Wolf Pack game so I should be spending my time studying...I can't wait to be done with Chem II Link to comment Share on other sites More sharing options...
eduggs Posted December 12, 2013 Share Posted December 12, 2013 Dry air doesn't seem to be much of a problem with a decent period of isentropic lift well ahead of the main storm. That should saturate the column pretty well and the 12z GFS shows the sounding near ALB getting saturated all the way up to 250 mb by 12z Saturday. It also has a large area near around -12C which would be very favorable for dendritic snow growth given the lift that will be present. I think 3" is probably on the low end for that area right now; the CIPS analogs as well have been keying in on a snowfall of around 6" for ENY. I agree with you. But in the back of my mind I can recall several instances when the GFS sounding looked amazing before an event... deep layer, saturated column, good lift in the snowgroth zone... only to have the morning sounding show a huge unmodeled dry layer and then subsequent poor reflectivities. I just don't trust the GFS forecast soundings. Link to comment Share on other sites More sharing options...
NorthShoreWx Posted December 12, 2013 Share Posted December 12, 2013 Ed, you're welcome in here. Thanks! I do feel welcome here. Link to comment Share on other sites More sharing options...
OceanStWx Posted December 12, 2013 Share Posted December 12, 2013 These guys must've never learned about shadowing... Well it's based on the top 15 analogs, so not every event will have a strong shadow signature. Link to comment Share on other sites More sharing options...
ORH_wxman Posted December 12, 2013 Share Posted December 12, 2013 I'll take this, based on the 60 hour GFS forecast. The general zones looks pretty good on that. The mid-level features are going to be good for CNE I think...SNE has the really strong thump potential, but that can be a bit more precarious. The temperatures in this one are going to be on the cold side of the analogs just taking a quick look at the actual analog dates....so I would lean a bit more enthusiastic for SNE Link to comment Share on other sites More sharing options...
eduggs Posted December 12, 2013 Share Posted December 12, 2013 Dry air doesn't seem to be much of a problem with a decent period of isentropic lift well ahead of the main storm. That should saturate the column pretty well and the 12z GFS shows the sounding near ALB getting saturated all the way up to 250 mb by 12z Saturday. It also has a large area near around -12C which would be very favorable for dendritic snow growth given the lift that will be present. I think 3" is probably on the low end for that area right now; the CIPS analogs as well have been keying in on a snowfall of around 6" for ENY. A little off topic, but almost everyone from outside the area always over forecasts snowfall for ALB. People think it's a snowier place than it really is. But I agree with you that this storm looks like a solid moderate snowfall at this point. Link to comment Share on other sites More sharing options...
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