BTRWx Posted November 27, 2013 Share Posted November 27, 2013 This is the precip that may legitimately be snow on the 12z NAM. Seems like the column is supportive of snow by 17-18z or so for DC/Balt and points west. The dca sounding is not all that great though. We're going to need some high rates. http://www.twisterdata.com/index.php?sounding.lat=38.9796&sounding.lon=-77.0523&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=09¶meter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false Link to comment Share on other sites More sharing options...
yoda Posted November 27, 2013 Share Posted November 27, 2013 This looks to me as a snow sounding completely by 18z. This is SW of Dale City in PW County http://www.twisterdata.com/index.php?sounding.lat=38.6629&sounding.lon=-77.2940&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=06¶meter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted November 27, 2013 Share Posted November 27, 2013 light snow falling here now. Link to comment Share on other sites More sharing options...
BTRWx Posted November 27, 2013 Share Posted November 27, 2013 This looks to me as a snow sounding completely by 18z. This is SW of Dale City in PW County http://www.twisterdata.com/index.php?sounding.lat=38.6629&sounding.lon=-77.2940&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=06¶meter=TMPF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false Sterling looks similar for that time period. http://www.twisterdata.com/index.php?sounding.lat=39.1289&sounding.lon=-77.5647&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=06¶meter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false Link to comment Share on other sites More sharing options...
WxUSAF Posted November 27, 2013 Share Posted November 27, 2013 The dca sounding is not all that great though. We're going to need some high rates. http://www.twisterdata.com/index.php?sounding.lat=38.9796&sounding.lon=-77.0523&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=09¶meter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false That sounding is perfectly fine for snow. It won't accumulate, but it will snow. Edit...you linked the 21z sounding, at which point the precip is done or very nearly done. At 18z it's more of a borderline sleet/snow sounding with a warm layer around 750-800mb that has temps near freezing. Link to comment Share on other sites More sharing options...
BTRWx Posted November 27, 2013 Share Posted November 27, 2013 That sounding is perfectly fine for snow. It won't accumulate, but it will snow. What is the highest altitude on a sounding that can correlate to precip-type at the surface? Link to comment Share on other sites More sharing options...
yoda Posted November 27, 2013 Share Posted November 27, 2013 The dca sounding is not all that great though. We're going to need some high rates. http://www.twisterdata.com/index.php?sounding.lat=38.9796&sounding.lon=-77.0523&sndclick=y&prog=forecast&model=NAM&grid=221&model_yyyy=2013&model_mm=11&model_dd=27&model_init_hh=12&fhour=09¶meter=SNOWIN&level=SURFACE&unit=none&maximize=n&mode=singlemap&sounding=y&output=image&view=large&archive=false Thats snow though. Yes, its not a great accumulating one, but its snow all the way Link to comment Share on other sites More sharing options...
mappy Posted November 27, 2013 Share Posted November 27, 2013 Oh good, so it should snow between 1-2 and last until 5, not stick, so I will miss it sitting at work. Awesome. Link to comment Share on other sites More sharing options...
Ian Posted November 27, 2013 Share Posted November 27, 2013 FLIZZARD TIME!!!! Link to comment Share on other sites More sharing options...
Ian Posted November 27, 2013 Share Posted November 27, 2013 Oh good, so it should snow between 1-2 and last until 5, not stick, so I will miss it sitting at work. Awesome. FLIZZARD!!!! Link to comment Share on other sites More sharing options...
clskinsfan Posted November 27, 2013 Share Posted November 27, 2013 Snow here. Lets see how long it lasts. Link to comment Share on other sites More sharing options...
mappy Posted November 27, 2013 Share Posted November 27, 2013 FLIZZARD!!!! you hitting the booze early? Link to comment Share on other sites More sharing options...
lsukev Posted November 27, 2013 Share Posted November 27, 2013 Thundersnow! Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted November 27, 2013 Share Posted November 27, 2013 Snow here. Lets see how long it lasts. Neither of us have to worry about shoveling. Link to comment Share on other sites More sharing options...
H2O Posted November 27, 2013 Share Posted November 27, 2013 Thundersnow! Where? Link to comment Share on other sites More sharing options...
mitchnick Posted November 27, 2013 Share Posted November 27, 2013 this has <insert date here> written all over it JI! Link to comment Share on other sites More sharing options...
yoda Posted November 27, 2013 Share Posted November 27, 2013 FLIZZARD!!!! SN-----? Link to comment Share on other sites More sharing options...
mitchnick Posted November 27, 2013 Share Posted November 27, 2013 I may actually be in a good spot for this....for once Link to comment Share on other sites More sharing options...
mitchnick Posted November 27, 2013 Share Posted November 27, 2013 nice radar DCA-BWI in line for some qpf; heavy stuff might speed up the cooling process too http://www.marylandwx.com/radar/klwxstate_br.php Link to comment Share on other sites More sharing options...
WxUSAF Posted November 27, 2013 Share Posted November 27, 2013 What is the highest altitude on a sounding that can correlate to precip-type at the surface? I'm not entirely sure I understand the question, but any altitude in which clouds and precip particles are forming is temperature dependent. Precip typically forms in winter storms below 500mb (about 1 mile altitude), but in summertime thunderstorms can form higher. Even in summer, rain droplets typically start as snow at those altitudes unless you're in the tropics but then warm as they fall. For winter precip type determination, it gets more complicated because the vertical temperature profile can waver back and forth above and below freezing with altitude. The 18z NAM sounding for DC, for example is borderline sleet or snow as I mentioned. The reason is that the snow might melt in that warm layer near 750-800mb if temps are above freezing, but then the column is below freezing from about 800mb-950mb. Then the rain droplets would refreeze into sleet. From 950mb to the surface it's not warm enough (and the warm layer isn't deep enough) to remelt those sleet pellets. FLIZZARD TIME!!!! SNOVEMBER! Link to comment Share on other sites More sharing options...
mitchnick Posted November 27, 2013 Share Posted November 27, 2013 pivot baby....well, sorta' http://www.ssd.noaa.gov/PS/PCPN/DATA/RT/na-wv-loop.html Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted November 27, 2013 Share Posted November 27, 2013 At this point I think you guys out east have the best chance. I hope you get it. Link to comment Share on other sites More sharing options...
BTRWx Posted November 27, 2013 Share Posted November 27, 2013 I'm not entirely sure I understand the question, but any altitude in which clouds and precip particles are forming is temperature dependent. Precip typically forms in winter storms below 500mb (about 1 mile altitude), but in summertime thunderstorms can form higher. Even in summer, rain droplets typically start as snow at those altitudes unless you're in the tropics but then warm as they fall. For winter precip type determination, it gets more complicated because the vertical temperature profile can waver back and forth above and below freezing with altitude. The 18z NAM sounding for DC, for example is borderline sleet or snow as I mentioned. The reason is that the snow might melt in that warm layer near 750-800mb if temps are above freezing, but then the column is below freezing from about 800mb-950mb. Then the rain droplets would refreeze into sleet. From 950mb to the surface it's not warm enough (and the warm layer isn't deep enough) to remelt those sleet pellets. SNOVEMBER! Thanks, the inability for the falling precipitation to fully melt near the surface is what confused me. Link to comment Share on other sites More sharing options...
snowdude Posted November 27, 2013 Share Posted November 27, 2013 Impressive temps early this morning on my way to work. 68 degrees at 4am and a few hours later, 20 degrees cooler. I'm not going to enjoy the winter here am I? #easternshoreproblems Link to comment Share on other sites More sharing options...
mappy Posted November 27, 2013 Share Posted November 27, 2013 Impressive temps early this morning on my way to work. 68 degrees at 4am and a few hours later, 20 degrees cooler. I'm not going to enjoy the winter here am I? #easternshoreproblems sbyobs.jpg Nope! PS. no contest today Link to comment Share on other sites More sharing options...
mitchnick Posted November 27, 2013 Share Posted November 27, 2013 Impressive temps early this morning on my way to work. 68 degrees at 4am and a few hours later, 20 degrees cooler. I'm not going to enjoy the winter here am I? #easternshoreproblems sbyobs.jpg my daughter just moved there; I like SBY and am pretty familiar with it as an old law school bud lives there and have visited him quite often in the last 30 years as you know, there have been more than a few storms over the years that we saw the sun through cirrus or had spits of snow while SBY had 6-12" that area seems to be on a roll the last few years too so I wouldn't count yourself out by any stretch Link to comment Share on other sites More sharing options...
lsukev Posted November 27, 2013 Share Posted November 27, 2013 12z GFS still showing light accumulations around the 95 corridor, with what looks to be decent rates for a time around 18z. Edit: I meant around 00z, not 18z Link to comment Share on other sites More sharing options...
lsukev Posted November 27, 2013 Share Posted November 27, 2013 Nevermind. Dang it. Some of you are probably asking how I can see the 12z GFS? I can't. Looking at the old one... Link to comment Share on other sites More sharing options...
usedtobe Posted November 27, 2013 Share Posted November 27, 2013 FLIZZARD TIME!!!! 36 or 37 degrees at DCA at 1PM......sort of a slushy flizzard. Link to comment Share on other sites More sharing options...
snowfan Posted November 27, 2013 Share Posted November 27, 2013 you need a timeout. Nevermind. Dang it. Some of you are probably asking how I can see the 12z GFS? I can't. Looking at the old one... Link to comment Share on other sites More sharing options...
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