JamieOber Posted February 4, 2014 Share Posted February 4, 2014 NWS upped UNV's snow amounts in the warning text. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted February 4, 2014 Share Posted February 4, 2014 RGEM was a sleetfest for UNV. I don't know, 4-6" may actually sound reasonable or even a tick too high... Link to comment Share on other sites More sharing options...
Santa Clause Posted February 4, 2014 Share Posted February 4, 2014 Sleet has me bummed, but I do hear it causes horrible travel which at least would be interesting. Link to comment Share on other sites More sharing options...
canderson Posted February 4, 2014 Share Posted February 4, 2014 So, tips on how to properly clear this mess? We made a bunch of mistakes on VD07 and I don't want to repeat them. Essentially then I shoveled the snow only to have sleet and zr create icecubes that couldn't be broken. Do I let everything sit until the event is done? Link to comment Share on other sites More sharing options...
JamieOber Posted February 4, 2014 Share Posted February 4, 2014 Sleet has me bummed, but I do hear it causes horrible travel which at least would be interesting. Yeah, especially when you're home listening to the scanner on the radio. That's a funny thing about being a weather nerd for me. If I'm home, and say we get a huge squall, I'm all "this is GREAT". If I'm driving, "this is GREAT" gets into a pitched battle with "I don't want to ****ing die". Link to comment Share on other sites More sharing options...
Hoar_Frost Posted February 4, 2014 Share Posted February 4, 2014 So, tips on how to properly clear this mess? We made a bunch of mistakes on VD07 and I don't want to repeat them. Essentially then I shoveled the snow only to have sleet and zr create icecubes that couldn't be broken. Do I let everything sit until the event is done? The key, if you ultimately want the sleet removed from whatever surface, is to do something with it before the temperature falls too far below freezing. But, it's hard. When I lived in Illinois, on 19 December (I think) 2008, we got four inches of sleet. It was godawful to remove, and most people just gave up. Link to comment Share on other sites More sharing options...
Santa Clause Posted February 4, 2014 Share Posted February 4, 2014 Hahaha I agree Jamie! This storm is going to be a huge impact basically all through the state... Long time since that's happened. Link to comment Share on other sites More sharing options...
Hoar_Frost Posted February 4, 2014 Share Posted February 4, 2014 NWS upped UNV's snow amounts in the warning text. More in line with the grid text. Link to comment Share on other sites More sharing options...
canderson Posted February 4, 2014 Share Posted February 4, 2014 The key, if you ultimately want the sleet removed from whatever surface, is to do something with it before the temperature falls too far below freezing. But, it's hard. When I lived in Illinois, on 19 December (I think) 2008, we got four inches of sleet. It was godawful to remove, and most people just gave up. It was 13 overnight and the plow pile at the end of my driveway isn't moving so essentially we're all f'd huh. Link to comment Share on other sites More sharing options...
Hoar_Frost Posted February 4, 2014 Share Posted February 4, 2014 Another thing to consider -- and I know PennMan mentioned this earlier in response to one of my posts -- is that precipitation rates will be quite high during much of this event. The morning AFD really hits this point hard. When precip rates are high like that, dynamic cooling (I hate that term, by the way) could be sufficient to drive a vertical column that might normally be marginal between sleet and snow (or freezing rain and sleet, etc.) toward the colder p-type (so, toward more snow in the snow/sleet question zone). This is a factor that models do not always (or really even usually) pick up too well on. Link to comment Share on other sites More sharing options...
Santa Clause Posted February 4, 2014 Share Posted February 4, 2014 Good lord is GFS close to a huge thump up here.. Tons of precip while 850 straddles I 80. Link to comment Share on other sites More sharing options...
MillvilleWx Posted February 4, 2014 Share Posted February 4, 2014 Short Range models continue to paint Southern Pa in the cross hairs of an Ice storm. RGEM is basically a killer for LSV up to Reading. These temps today are slowly rising, but the areas that can't make it to 30 degrees today south of say 76 might be in trouble for tomorrow morning. At campus, the snow is basically caked on trees and cars. Adding sleet and freezing rain on top will just make it a brick. If you are prone to losing power around the southern area, I would probably prep up, just my 2 cents. Can never be too prepared for ice really. Those of you up north, enjoy the snow, although some sleet might mix in which would really be a bummer. Soundings for these present runs should be interesting to look at Link to comment Share on other sites More sharing options...
djr5001 Posted February 4, 2014 Share Posted February 4, 2014 I have a question for a red tagger or anyone in the know. I am looking at the text output from the 12Z Nam for LNS and notice the temperatures are given in 50mb increments in the upper levels. What do you look for to deferentiate sleet from freezing rain? Obvoiusly snow would be below 0C through all levels down to 1000mb and rain would be above 0C through all levels down to 1000mb. What temperature profile creates sleet and what profile creates freezing rain. Thanks. sleet occurs when there is a warm layer aloft and cold layer to freeze the precipitation before it reaches the ground... freezing rain has warmer air near the surface to melt the frozen precipitation and then freezes at the surface... the shallower the warm layer at the surface the more supercooled the droplet will be when it reaches the surface so with a sounding or upper level data I would look for where the warm layer is and how thick it is first and then look to see profile near the surface to see if it will likely freeze before reaching the surface or not Link to comment Share on other sites More sharing options...
Hoar_Frost Posted February 4, 2014 Share Posted February 4, 2014 It was 13 overnight and the plow pile at the end of my driveway isn't moving so essentially we're all f'd huh. Yep -- I was sure to extricate my car from the snow yesterday before sunset. This freezing of precip into a block of ice could be a problem whether it's mainly sleet or mainly snow since the snow will be low-ratio snow. Link to comment Share on other sites More sharing options...
Santa Clause Posted February 4, 2014 Share Posted February 4, 2014 Anyone know what rgem qpf looked like? Link to comment Share on other sites More sharing options...
NortheastPAWx Posted February 4, 2014 Share Posted February 4, 2014 GFS is really close to a big event here. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 4, 2014 Share Posted February 4, 2014 RGEM was a sleetfest for UNV. I don't know, 4-6" may actually sound reasonable or even a tick too high... This will be very close for places north of a line from Altoona to Harrisburg in central PA tonight. Most of the precip comes in a heavy WAA burst, and often times if the precip rate is intense enough, the combination of convective cooling and CAD can hold the precip to snow or at least a snow/sleet mix enough for an extra couple hours, and in those bands that is enough to be the difference between 3 and 7" for example. It will depend on meso scale issues that are almost impossible to predict that precisely ahead of time. Just something to watch tonight. It would help if the precip comes in fast and intense though, that is for sure. NAM/RGEM trend this morning was not great. Link to comment Share on other sites More sharing options...
MillvilleWx Posted February 4, 2014 Share Posted February 4, 2014 Anyone know what rgem qpf looked like? Very wet for much of Pa. Over an inch from HBG up to NEPA into NJ. WIlliamsport was around an inch with pretty much all snow and a touch of sleet. Sleet and ZR galore south of Reading Link to comment Share on other sites More sharing options...
psuhoffman Posted February 4, 2014 Share Posted February 4, 2014 So, tips on how to properly clear this mess? We made a bunch of mistakes on VD07 and I don't want to repeat them. Essentially then I shoveled the snow only to have sleet and zr create icecubes that couldn't be broken. Do I let everything sit until the event is done? Having lots of experience from my days in northwest VA in the 90's, it is much easier to remove if you wait until the storm is over and leave whatever layer of snow falls beneith the ice layer. Then use a garden shovel and you can punch through to the softer snow below and scrape from the bottom up. This only works if you get more then about 2" of snow. Less then that and the snow will just saturate and add to the solid ice. Link to comment Share on other sites More sharing options...
Festus Posted February 4, 2014 Share Posted February 4, 2014 URGENT - WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE STATE COLLEGE PA 1022 AM EST TUE FEB 4 2014 PAZ056-057-059-063>066-050130- /O.EXT.KCTP.WS.W.0004.140205T0000Z-140205T2100Z/ PERRY-DAUPHIN-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER- INCLUDING THE CITIES OF...NEWPORT...HARRISBURG...HERSHEY... LEBANON...CARLISLE...GETTYSBURG...YORK...LANCASTER 1022 AM EST TUE FEB 4 2014...WINTER STORM WARNING NOW IN EFFECT FROM 7 PM THIS EVENING TO4 PM EST WEDNESDAY... * SNOW ACCUMULATIONS...2 TO 4 INCHES.* ICE ACCUMULATIONS...0.10 TO 0.25 INCHES.* TIMING...SNOW WILL BEGIN LATE TONIGHT AND CHANGE TO SLEET AND FREEZING RAIN DURING THE PRE-DAWN AND EARLY MORNING HOURS ON WEDNESDAY. A TRANSITION TO RAIN OR FREEZING RAIN IS EXPECTED BY NOON WEDNESDAY. THE WINTRY PRECIPITATION WILL END BY WEDNESDAY AFTERNOON.* IMPACTS...DANGEROUS TRAVEL CONDITIONS DUE TO SNOW/ICE COVERED ROADS AND REDUCED VISIBILITY. SNOW AND ICE ACCUMULATION ON TREES AND UTILITY LINES MAY CAUSE POWER OUTAGES. THE WEDNESDAY MORNING COMMUTE WILL BE SEVERELY IMPACTED. PRECAUTIONARY/PREPAREDNESS ACTIONS...DANGEROUS WINTER WEATHER CONDITIONS ARE EXPECTED OR OCCURRING.USE EXTREME CAUTION IF PLANNING TO TRAVEL. FOR THE LATEST WEATHER INFORMATION...GO TO WEATHER.GOV/CTP OR STAY TUNED TO NOAA WEATHER RADIO. REPORT SNOW AND ICE ACCUMULATION TO THE NATIONAL WEATHER SERVICE STATE COLLEGE BY SENDING AN EMAIL TO [email protected]... POSTING TO THE NWS STATE COLLEGE FACEBOOK PAGE...OR TWEET @NWSSTATECOLLEGE WITH THE HASHTAG #CTPWX. This seems like it's missing some qpf? Maybe less accretion if rain rates are heavy? Link to comment Share on other sites More sharing options...
Hoar_Frost Posted February 4, 2014 Share Posted February 4, 2014 Given the issues regarding precip rate and induced cooling, I would say the GFS might be closer to a big event for the I-80 corridor (including State College) than you think. I'm sticking with my call of 8" for now. Link to comment Share on other sites More sharing options...
djr5001 Posted February 4, 2014 Share Posted February 4, 2014 Another thing to consider -- and I know PennMan mentioned this earlier in response to one of my posts -- is that precipitation rates will be quite high during much of this event. The morning AFD really hits this point hard. When precip rates are high like that, dynamic cooling (I hate that term, by the way) could be sufficient to drive a vertical column that might normally be marginal between sleet and snow (or freezing rain and sleet, etc.) toward the colder p-type (so, toward more snow in the snow/sleet question zone). This is a factor that models do not always (or really even usually) pick up too well on. 12z GFS sounding for around Harrisburg would be a good case of this... has profile that supports snow until right before 12z tomorrow morning, but is during the peak of the event... if this dynamic cooling delays the changeover the Harrisburg region may manage to stay all snow a little longer... if not this region will be in the battle ground for the snow/sleet changeover line at the height of the storm Link to comment Share on other sites More sharing options...
Vogan Posted February 4, 2014 Share Posted February 4, 2014 sleet occurs when there is a warm layer aloft and cold layer to freeze the precipitation before it reaches the ground... freezing rain has warmer air near the surface to melt the frozen precipitation and then freezes at the surface... the shallower the warm layer at the surface the more supercooled the droplet will be when it reaches the surface so with a sounding or upper level data I would look for where the warm layer is and how thick it is first and then look to see profile near the surface to see if it will likely freeze before reaching the surface or not That makes sense. How deep does the freezing layer at the surface have to be create sleet? Link to comment Share on other sites More sharing options...
PennMan Posted February 4, 2014 Share Posted February 4, 2014 Another thing to consider -- and I know PennMan mentioned this earlier in response to one of my posts -- is that precipitation rates will be quite high during much of this event. The morning AFD really hits this point hard. When precip rates are high like that, dynamic cooling (I hate that term, by the way) could be sufficient to drive a vertical column that might normally be marginal between sleet and snow (or freezing rain and sleet, etc.) toward the colder p-type (so, toward more snow in the snow/sleet question zone). This is a factor that models do not always (or really even usually) pick up too well on.Might see the sleet/snow line move northward pretty quickly to a point and then stall for awhile...I'm hoping somewhere south of Centre County.We had an event here in early December 2009 where we were forecast to go over to sleet after an inch or two of snow, but thanks to very heavy precip rates we remained heavy snow for a few extra hours and ended up near 7". On the flip side, I've also seen us flip to sleet hours before forecast. I know I'll be anxiously reading posts from our Johnstown-Altoona posters overnight to see where things stand. Also being 9.5 miles NNE of State College won't be a bad thing. Link to comment Share on other sites More sharing options...
djr5001 Posted February 4, 2014 Share Posted February 4, 2014 That makes sense. How deep does the freezing layer at the surface have to be create sleet? I think it would depend on how much the droplet warms aloft before reaching the colder air... a shallow warm air aloft that is warm just enough to melt may not need a very thick layer above the surface to refreeze before impact with the surface Link to comment Share on other sites More sharing options...
psuhoffman Posted February 4, 2014 Share Posted February 4, 2014 12z GFS sounding for around Harrisburg would be a good case of this... has profile that supports snow until right before 12z tomorrow morning, but is during the peak of the event... if this dynamic cooling delays the changeover the Harrisburg region may manage to stay all snow a little longer... if not this region will be in the battle ground for the snow/sleet changeover line at the height of the storm Not sure about this, the profile supports snow for sure at 1am, but by 4am there is a pretty substantial warm layer from 850 up to 750. I doubt that would still be snow, maybe sleet in heavier precip. Looks like the first .2 or so is definitely snow, then after that sleet to frz rain. All the guidance I saw trended worse at 12z. Nothing was a huge jump but even a slight north trend is no good when you were already right on the line between snow and ice. The primary seems to want to hang on just a little bit longer on todays runs and that is a killer for places between 80 and the turnpike that were on the fence. I would lean more ice vs snow right now, especially down towards the turnpike. Link to comment Share on other sites More sharing options...
Vogan Posted February 4, 2014 Share Posted February 4, 2014 I think it would depend on how much the droplet warms aloft before reaching the colder air... a shallow warm air aloft that is warm just enough to melt may not need a very thick layer above the surface to refreeze before impact with the surface Ahaa, that makes sense as well. Thanks. Link to comment Share on other sites More sharing options...
Santa Clause Posted February 4, 2014 Share Posted February 4, 2014 I'm just glad it's soo juiced up. No matter what precip we get its going to be very ugly. Link to comment Share on other sites More sharing options...
heavy_wx Posted February 4, 2014 Share Posted February 4, 2014 The 12z GFS actually looks a bit colder with UNV completely below freezing at 09z Wednesday. It has about 0.7" QPF in the 6 hours preceding that time. Link to comment Share on other sites More sharing options...
djr5001 Posted February 4, 2014 Share Posted February 4, 2014 Not sure about this, the profile supports snow for sure at 1am, but by 4am there is a pretty substantial warm layer from 850 up to 750. I doubt that would still be snow, maybe sleet in heavier precip. Looks like the first .2 or so is definitely snow, then after that sleet to frz rain. All the guidance I saw trended worse at 12z. Nothing was a huge jump but even a slight north trend is no good when you were already right on the line between snow and ice. The primary seems to want to hang on just a little bit longer on todays runs and that is a killer for places between 80 and the turnpike that were on the fence. I would lean more ice vs snow right now, especially down towards the turnpike. I took a look again and the grid point to the north of Harrisburg supports my previous post but the gridpoint south shows exactly what you described for 4am... I must have been thinking it was colder than what it is for the southern grid point but you are right Link to comment Share on other sites More sharing options...
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