Rainshadow Posted January 26, 2013 Share Posted January 26, 2013 I thought this would be an interesting case because of the strong winds aloft and low temperatures. I would have liked to have had a heavier event to level the field a bit better. But you'll notice that just because you are colder (north), doesn't mean the ratios are necessarily better. I don't know if I'll be able to get a bufkit crosshair sounding, but the best ratios were right around PHL. There were only two CoCoRahs reports from PHL proper, but there are a boatload from Montgomery County. There were no CoCoRahs reports from Delaware County this morning. In this event dendritic growth was >>>>>> strong winds aloft. Snow/Water Equivalent Ratio Berks 19:1 Bucks 26:1 Carbon 18:1 Chester 22:1 Lehigh 14:1 Monroe 10:1 Montgomery 30:1 Northampton 20:1 Philadelphia 27:1 Kent De 15:1 New Castle De 13:1 Sussex De 11:1 MD Ern Shore 11:1 Atlantic 18:1 Burlington 21:1 Camden 20:1 Cape May 15:1 Cumberland 13:1 Gloucester 20:1 Hunterdon 17:1 Mercer 18:1 Middlesex 16:1 Monmouth 16:1 Morris 13:1 Ocean 14:1 Salem 12:1 Somerset 15:1 Sussex 18:1 Warren 14:1 Link to comment Share on other sites More sharing options...
eastonwx Posted January 26, 2013 Share Posted January 26, 2013 Tony, what role does elevation play in ratios? Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 Tony, what role does elevation play in ratios? From a cloud microphysic perspective, it doesn't. But because they are colder, less is loss to melting and I suppose in more marginal moisture situations they also lose less to evaporation on the way down. Link to comment Share on other sites More sharing options...
tombo82685 Posted January 26, 2013 Share Posted January 26, 2013 you might get another shot next friday to test the ratio theory with a clipper. Link to comment Share on other sites More sharing options...
eastonwx Posted January 26, 2013 Share Posted January 26, 2013 From a cloud microphysic perspective, it doesn't. But because they are colder, less is loss to melting and I suppose in more marginal moisture situations they also lose less to evaporation on the way down. Thanks for the explanation. I was just wondering because a reporting station about 10 miles from me had a slightly higher ratio, 20:1 vs. 17.5:1) but the station is about 400' higher. It could also be a slight inaccuracy in measuring? Link to comment Share on other sites More sharing options...
chubbs Posted January 26, 2013 Share Posted January 26, 2013 Tony - Interesting. The northern areas could have been too cold. Also wonder if the better bands also produced a higher snow ratio. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 Thanks for the explanation. I was just wondering because a reporting station about 10 miles from me had a slightly higher ratio, 20:1 vs. 17.5:1) but the station is about 400' higher. It could also be a slight inaccuracy in measuring? The snowfall was light, so a .01 here or there can account for that difference. In this instance elevation should not have mattered. One of the reasons I wish the snow was heavier, would have removed some of the background noise. There is another non-Cocorahs person who e-mails in a report from Pocono Summit Monroe County and he also had a straight 10:1. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 Tony - Interesting. The northern areas could have been too cold. Also wonder if the better bands also produced a higher snow ratio. I believe so. I remember that Jan 2005 event where we had 10:1 & 20:1 ratios during different parts of the same storm. Link to comment Share on other sites More sharing options...
AlexD Posted January 26, 2013 Share Posted January 26, 2013 The ratios in Sussex were only 11-1? That surprises me, the snow that I witnessed was very powdery Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 The ratios in Sussex were only 11-1? That surprises me, the snow that I witnessed was very powdery There were five reports, they all were about the same ratio. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 you might get another shot next friday to test the ratio theory with a clipper. Maybe Sunday too. Link to comment Share on other sites More sharing options...
am19psu Posted January 26, 2013 Share Posted January 26, 2013 Denominator precision is making a bigger difference than actual weather differences for the 17.5 vs. 20 question Link to comment Share on other sites More sharing options...
Dsnowx53 Posted January 26, 2013 Share Posted January 26, 2013 Could heavier precipitation rates lead to more evaporational cooling aloft, thus bringing the snow growth regions down to ideal dendritic growth temperatures? Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 Could heavier precipitation rates lead to more evaporational cooling aloft, thus bringing the snow growth regions down to ideal dendritic growth temperatures? I dont know if I can, but I'll check the profile with this one to see if that occurred. Link to comment Share on other sites More sharing options...
famartin Posted January 26, 2013 Share Posted January 26, 2013 I dont know if I can, but I'll check the profile with this one to see if that occurred. Here was the initialization sounding from TTN... isothermal in the perfect spot. Link to comment Share on other sites More sharing options...
famartin Posted January 26, 2013 Share Posted January 26, 2013 Mercer 18:1 I wonder if the fact many CoCoRaHS observers may wait til the next morning to measure may artificially lower ratios. (Parents had 22:1, 0.06" liquid for 1.3" snow) With snow so fluffy, compression probably happened fairly quickly. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 26, 2013 Author Share Posted January 26, 2013 I wonder if the fact many CoCoRaHS observers may wait til the next morning to measure may artificially lower ratios. (Parents had 22:1, 0.06" liquid for 1.3" snow) With snow so fluffy, compression probably happened fairly quickly. Post # 12. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 27, 2013 Author Share Posted January 27, 2013 Could heavier precipitation rates lead to more evaporational cooling aloft, thus bringing the snow growth regions down to ideal dendritic growth temperatures? In this case it wasnt. A lot going on with this image. Time goes right to left in this image. Max omega and temp cross hairs occurred about 21z at PHL (apologies the time stamp was cut off). About 55 kts of wind in there too. Link to comment Share on other sites More sharing options...
tombo82685 Posted January 29, 2013 Share Posted January 29, 2013 bump for the possibility of doing this again this friday. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 29, 2013 Author Share Posted January 29, 2013 bump for the possibility of doing this again this friday. Do I have to post that the winds in the snow growth region will knock down the ratios again? Link to comment Share on other sites More sharing options...
tombo82685 Posted January 29, 2013 Share Posted January 29, 2013 Do I have to post that the winds in the snow growth region will knock down the ratios again? yes and also the mountains will eat the moisture up. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 30, 2013 Author Share Posted January 30, 2013 You know what, if ends up interesting, I'll re-do the same analysis on the weekend. Oh, the wind field will shatter the crystals and the ratio will be 9:1 and the mountains are going to destroy the snow like Gallagher at a fruit stand. Link to comment Share on other sites More sharing options...
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