JamieOber Posted December 6, 2013 Share Posted December 6, 2013 VIsibility just dropped pretty substantially in Johnstown. They're still reporting freezing rain, but I wonder if maybe snow is mixing in. Doesn't look like much on 511 traffic cam. Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Just went outside. Mostly rain again, a bit of sleet mixed in. Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Doesn't look like much on 511 traffic cam. They're reporting light snow now: http://www.wrh.noaa.gov/mesowest/getobext.php?wfo=sew&sid=kjst&num=60&banner=on Link to comment Share on other sites More sharing options...
Wmsptwx Posted December 6, 2013 Share Posted December 6, 2013 Uhhoh rain and sleet here...thinking that layer might have some staying power! Link to comment Share on other sites More sharing options...
phil882 Posted December 6, 2013 Share Posted December 6, 2013 700mb is at -1c http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=16# Check it out yourself. 850mb 0c is just barely north of SC. And they don't plot 800mb, which is probably +1C (but falling), hence the rain/sleet mix instead of a rain/snow mix. Keep in mind the SPC fields are just the 1 hour forecast from the RAP. Its not always 100% accurate. Per RAP soundings near State College look to still have a warm nose between 850 and 700 hPa. The good news is that despite the fact that its a pretty thick layer its only about 1-2 deg C deep, which will easily be overcome by melting snow (as long as the precipitation rates ramp up) Link to comment Share on other sites More sharing options...
JamieOber Posted December 6, 2013 Share Posted December 6, 2013 Just went outside. Mostly rain again, a bit of sleet mixed in. Getting a bit of a bad feeling about this. Link to comment Share on other sites More sharing options...
F5TornadoF5 Posted December 6, 2013 Share Posted December 6, 2013 850mb 0c has passed State College now...about 30 miles south now. Come on!! 20min!!! Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Thinking that band moving into SW PA right now is the one that's going to push us over to snow here in State College. Looks awesome! Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 6, 2013 Share Posted December 6, 2013 Getting a bit of a bad feeling about this. Agreed...shouldn't be still liquid at this point... Link to comment Share on other sites More sharing options...
JamieOber Posted December 6, 2013 Share Posted December 6, 2013 Keep in mind the SPC fields are just the 1 hour forecast from the RAP. Its not always 100% accurate. Per RAP soundings near State College look to still have a warm nose between 850 and 700 hPa. The good news is that despite the fact that its a pretty thick layer its only about 1-2 deg C deep, which will easily be overcome by melting snow (as long as the precipitation rates ramp up) That's just it. Seems like, at the moment, the best rates are passing to our south. Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Getting a bit of a bad feeling about this. I'm not worried. Models didn't have the changeover 'til 00z plus or minus an hour or so. Johnstown and Clearfield are already over to snow and they weren't supposed to be for another hour or two yet. We'll be good. Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Agreed...shouldn't be still liquid at this point... Yes it should. Supposed to be liquid or a mix through about 7PMish. Surface temperatures aren't supposed to be 34F 'til around then either. Link to comment Share on other sites More sharing options...
JamieOber Posted December 6, 2013 Share Posted December 6, 2013 I'm not worried. Models didn't have the changeover 'til 00z plus or minus an hour or so. Johnstown and Clearfield are already over to snow and they weren't supposed to be for another hour or two yet. We'll be good. Ah, gotcha. That's good. Also, seems like it's going to precip a long time. Link to comment Share on other sites More sharing options...
jm1220 Posted December 6, 2013 Share Posted December 6, 2013 Getting a bit of a bad feeling about this. I'm not worried. Models didn't have the changeover 'til 00z plus or minus an hour or so. Johnstown and Clearfield are already over to snow and they weren't supposed to be for another hour or two yet. We'll be good. Exactly. I think State College is in a great spot for some of the best snow from this. It should be a fun 4-6 hours. I don't think UNV was the jackpot/lollipop once in all the time I lived there!! Just have to bear some patience. Link to comment Share on other sites More sharing options...
F5TornadoF5 Posted December 6, 2013 Share Posted December 6, 2013 Here comes all the negative posts haha. Relax guys it wasn't suppose to turn over until like 7-8pm. Link to comment Share on other sites More sharing options...
NeffsvilleWx Posted December 6, 2013 Share Posted December 6, 2013 Here comes all the negative posts haha. Relax guys it wasn't suppose to turn over until like 7-8pm. No one here is negative, you're just being a weenie and people don't like that. Arguing with a met's analysis is generally poor form. You remind me of wmsptwx from a few years ago. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 6, 2013 Share Posted December 6, 2013 Yes it should. Supposed to be liquid or a mix through about 7PMish. Surface temperatures aren't supposed to be 34F 'til around then either. Well, you are the met...hope you're right. Link to comment Share on other sites More sharing options...
F5TornadoF5 Posted December 6, 2013 Share Posted December 6, 2013 No one here is negative, you're just being a weenie and people don't like that. Arguing with a met's analysis is generally poor form. Yes I'm being a weenie, but I'm not arguing the analysis. Was a former Met student myself at PSU. Things are interpreted based off one's perspective. I was not trying to be disrespectful in any matter. Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Well, you are the met...hope you're right. me too Link to comment Share on other sites More sharing options...
irvingtwosmokes Posted December 6, 2013 Share Posted December 6, 2013 I'm all steady sleet in J'town Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 I'm all steady sleet in J'town Make sure to let us know when you start seeing snowflakes! Link to comment Share on other sites More sharing options...
F5TornadoF5 Posted December 6, 2013 Share Posted December 6, 2013 Make sure to let us know when you start seeing snowflakes! Well I was wrong haha . Since it's not snowing in Johnstown yet. I still think we have another hour or so to go. Link to comment Share on other sites More sharing options...
phil882 Posted December 6, 2013 Share Posted December 6, 2013 in the 700-800mb layer it is not like 1000-900 where precip falling though it can help cool.... the 700-800mb layer can hurt snow growth in the clouds... hence the sleet The snow growth region is based upon where temperatures are between ~12-18 deg C. This can oscillate quite a bit between different systems or even during the same event. In this case its up around 550-450 hPa. Ice melting is always an endothermic reaction which extracts heat from the atmosphere. The net impact is cooling of the surrounding atmosphere where ice particles are melting. The reason why there is sleet is because below this above freezing layer (in which ice crystals are melting) the precipitation is refreezing in the 1000-850 hPa cold pool. Refreezing water is an exothermic reaction which releases heat. However, this is not resulting in rising temperatures near the surface because there is CAA near the surface (note the NW winds advecting colder low-level temperatures from further NW). Thus in marginal thermodynamic cases such as this, the precipitation rate plays a key role in modulating the vertical profile of the atmosphere. If you get heavy enough precipitation, the melting in the warm nose can modify this portion of the profile to isothermal, allowing snow to exist all the way to the surface. Link to comment Share on other sites More sharing options...
irvingtwosmokes Posted December 6, 2013 Share Posted December 6, 2013 Now heavy rain Link to comment Share on other sites More sharing options...
F5TornadoF5 Posted December 6, 2013 Share Posted December 6, 2013 Now heavy rain What's your temperature? Is that 29 correct? Link to comment Share on other sites More sharing options...
Mallow Posted December 6, 2013 Share Posted December 6, 2013 Now heavy rain Ya, the airport went back to ZR. Hmm... Link to comment Share on other sites More sharing options...
Rick G Posted December 6, 2013 Share Posted December 6, 2013 sleet in Wilkes-Barre, Temp is 34.5 I have a theory of how sleet forms: the snowflakes are the daddies (because they are sooooo cool) and the rain drops are the mommies (how many of you saw your mommy shed tears), they get together and baby sleets are born. Again I am not a met and I could be wrong.... Link to comment Share on other sites More sharing options...
irvingtwosmokes Posted December 6, 2013 Share Posted December 6, 2013 What's your temperature? Is that 29 correct? Right around freezing. I'm sitting roughly at 1400 ft elev Link to comment Share on other sites More sharing options...
djr5001 Posted December 6, 2013 Share Posted December 6, 2013 The snow growth region is based upon where temperatures are between ~12-18 deg C. This can oscillate quite a bit between different systems or even during the same event. In this case its up around 550-450 hPa. Ice melting is always an endothermic reaction which extracts heat from the atmosphere. The net impact is cooling of the surrounding atmosphere where ice particles are melting. The reason why there is sleet is because below this above freezing layer (in which ice crystals are melting) the precipitation is refreezing in the 1000-850 hPa cold pool. Refreezing water is an exothermic reaction which releases heat. However, this is not resulting in rising temperatures near the surface because there is CAA near the surface (note the NW winds advecting colder low-level temperatures from further NW). Thus in marginal thermodynamic cases such as this, the precipitation rate plays a key role in modulating the vertical profile of the atmosphere. If you get heavy enough precipitation, the melting in the warm nose can modify this portion of the profile to isothermal, allowing snow to exist all the way to the surface. yea i re-read what i posted and tried to delete before anyone saw lol Link to comment Share on other sites More sharing options...
NortheastPAWx Posted December 6, 2013 Share Posted December 6, 2013 We got to get this rain out of here. Link to comment Share on other sites More sharing options...
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