Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

Thanksgiving Week Nor'easter Discussion


Zelocita Weather

Recommended Posts

  • Replies 769
  • Created
  • Last Reply

The one on weather underground shows something like that except move the snow line 50 miles NW

If you look at the zoomed in maps that I have, almost no precipitation is falling where it would be cold enough for snow. I suspect that if it comes down heavy enough, dynamic cooling will become a factor and we could snow with the surface in the mid 30's. The 00z Euro has a period of greater than 0.75" per hour water equivalent rates from KMMU south and east.

Link to comment
Share on other sites

I agree that I'd be happy with an inland runner because the dry conditions are starting to become very concerning. We are probably on the cusp of a lot more serious problems and every week of little rain causing increasingly lower stream flows, dry soils, and lessening reservoirs. A nice soaking rainstorm would be very helpful right about now and getting at least an inch to an inch an a half of rain is a good start.

 

The 06z gfs backed off though and we're still dealing with a progressive pattern so I fear this storm will slip OTS. 

Link to comment
Share on other sites

Thanks for your observations everyone. I don't know whether this is the best place to ask. Apologies if the question is lame. Amateurish of amateur here.

 

But how the rain/snow line is determined? Or how do we know from the model maps that precipitation is rain or snow ? Is it based on the 0 line in the 500mb map?  All I understood from these forum was that it is not a single factor which determines that. Water temperature in Atlantic, surface temp or even just being Oct or Nov has been some reasons I've seen.

 

For example, in this model run for this storm ( http://www.instantweathermaps.com/GFS-php/showmap-conusncep.php?run=2013112018&var=PCPPRSTMP_850mb&hour=177 ), how do I know that the 0.1in precipitation is going to be snow or rain over central NJ?

 

Please delete/move it to a different if not appropriate here. Thanks.

Link to comment
Share on other sites

Thanks for your observations everyone. I don't know whether this is the best place to ask. Apologies if the question is lame. Amateurish of amateur here.

 

But how the rain/snow line is determined? Or how do we know from the model maps that precipitation is rain or snow ? Is it based on the 0 line in the 500mb map?  All I understood from these forum was that it is not a single factor which determines that. Water temperature in Atlantic, surface temp or even just being Oct or Nov has been some reasons I've seen.

 

For example, in this model run for this storm ( http://www.instantweathermaps.com/GFS-php/showmap-conusncep.php?run=2013112018&var=PCPPRSTMP_850mb&hour=177 ), how do I know that the 0.1in precipitation is going to be snow or rain over central NJ?

 

Please delete/move it to a different if not appropriate here. Thanks.

The best way to get an idea is by looking at the 850mb maps. In most cases that's a good start because it tells you what the temps are going to be in the mid-levels and if that's above freezing it's going to be hard to get frozen precip. So on the map you looked at, that blue line labeled 0c is the 850mb freezing line. You also have to take into account lower level temps as well. These lower level temps or 2m temps you may have to hunt for more with particular models. As you gain more knowledge you may start looking at the other levels as well. For example, the 2m temps and the 850mb temps might be below freezing but a warm punch occurs at the mid-levels, that could be a setup for sleet. If 2m temps are below freezing but 850mb temps are not, that could be an indicator of possible freezing rain. To put it all together, a lot of factors go into determining precipitation type and it's not as cut and dry as looking at 850mb freezing line on a map.

Link to comment
Share on other sites

It's back to showing the double barreled lows. I still think that the models are having a very hard time resolving that initial burst of heavy convection down south. The GFS wants to form a low there in despite of the trough still being hung up over Alabama.

 

We have to wait until both streams can be better sampled to know for sure.

Link to comment
Share on other sites

Main difference I see so far is that the southern stream is weaker this run.

The models are showing more energy and moisture in the southern stream with each shortwave than there's likely to be for the time-being and near-term future. Down the road, eventually, we will probably see closer to what the models are now showing but this will likely be an extremely gradual change.

WX/PT

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...