WxUSAF Posted February 21, 2011 Author Share Posted February 21, 2011 http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html RGEM looks very nice...if I'm doing my mm to inches conversion right (with 10:1 ratios), most of central/northern MD, far NVA, and WV panhandle would be 6"+, with probably 4" for DC. RGEM says only a brief period of light rain/drizzle before changeover and heavier precip arrives. Snow falls at about 1"/hour. Link to comment Share on other sites More sharing options...
usedtobe Posted February 21, 2011 Share Posted February 21, 2011 Surprised at how low the bufkit ratios are for the 06z GFS/NAM runs. Only generally 6 to 8:1 at the heaviest snow. That's because of the temperature in the warm layer, they are below freezing but are in the temp range where lots of riming typically is found. At 700 mb the temp is minus 1.1. Not that far from freezing. ratios are dependent on the temps where the snow is being formed not surface temps. Essentially bufkit is saying w're not going to see dendrites at that time and that the flakes might be rimed. 5 800 1843 -2.8 -2.8 100 0.0 -2.8 212 22 288.2 288.9 281.1 299.4 3.89 6 750 2357 -1.1 -1.1 100 0.0 -1.1 234 46 295.4 296.3 285.1 309.3 4.72 7 700 2907 -2.2 -2.2 100 0.0 -2.2 246 58 300.1 300.9 286.8 314.0 4.65 8 650 3495 -4.4 -4.6 98 0.3 -4.5 254 67 304.0 304.8 287.7 316.8 4.17 Link to comment Share on other sites More sharing options...
mappy Posted February 21, 2011 Share Posted February 21, 2011 Missed this post For you+BWI I'll say 4-7" with local amounts hitting 8" Thanks Mark! Link to comment Share on other sites More sharing options...
Ian Posted February 21, 2011 Share Posted February 21, 2011 after wes posts move here: Link to comment Share on other sites More sharing options...
usedtobe Posted February 21, 2011 Share Posted February 21, 2011 i dunno, im going to leave it for now.. it's a fine line in some instances I've certainly underplayed this but during the events last year and the JAn 26 event, think my guesses were pretty good. I don't balme the mets for being conservative. It's pretty easy for enthusiasts (not you) to forecast heavy snow for each event that a model shows as having potential for heavy snow. It's tougher when you are making public forecast. I got killed after the boxer day non-storm and the CWG forecasts were the least bullish in the area. Now people are complaining about forecasts that haven't yet verified for this event when the models except for the Euro were not very bullish until the 00Z run. Link to comment Share on other sites More sharing options...
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