Jump to content
  • Member Statistics

    17,586
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

January 24th-26th potential winter storm part 2


Hoosier

Recommended Posts

  • Replies 777
  • Created
  • Last Reply

The 12z suites had major struggles organizing heights properly. Everything comes in to far east from where it should if you allign it to the northern stream, which makes the northern stream act as a "kicker" which it isn't. This happens time and time again with these models. It happened last February 5-6 also. Remember the Globals/NAM in the 72-96hr timeframe..........I don't want to lol.

well this has big implications

we will see if you are right Angry hopefully u are

Link to comment
Share on other sites

The 12z suites had major struggles organizing heights properly. Everything comes in to far east from where it should if you allign it to the northern stream, which makes the northern stream act as a "kicker" which it isn't. This happens time and time again with these models. It happened last February 5-6 also. Remember the Globals/NAM in the 72-96hr timeframe..........I don't want to lol.

this is the 18z nam and 12z gfs same timeframe. If that 5h is correct with that energy out west...chances are a progressive solution like the nam is very realistic

just keep'n it real

Link to comment
Share on other sites

do the 6z and 18z ncep models ingest new data or do they work off the previous samples?

They will pull in new data (from satellites, etc as well as any special soundings), but are initialized from the previous model runs. The common misconception is that 00z/12z runs initialize with new data. In fact they are also initialized from the previous runs, but the have the benefit of the upper air network which is used to nudge the initialized fields towards reality.

Link to comment
Share on other sites

They will pull in new data (from satellites, etc as well as any special soundings), but are initialized from the previous model runs. The common misconception is that 00z/12z runs initialize with new data. In fact they are also initialized from the previous runs, but the have the benefit of the upper air network which is used to nudge the initialized fields towards reality.

thank you for the clairification

Link to comment
Share on other sites

They will pull in new data (from satellites, etc as well as any special soundings), but are initialized from the previous model runs. The common misconception is that 00z/12z runs initialize with new data. In fact they are also initialized from the previous runs, but the have the benefit of the upper air network which is used to nudge the initialized fields towards reality.

thank you for the clairification

dtk hangs out in the eastern threads--but he works out at NCEP on the GFS. He also had this info on the NAM for anyone interested:

"I don't have much to add as I'm not even sure I fully understand why the NAM had (still has?) a drift in the large scale (though there are various hypotheses related to the model itself, various DA aspects including bias correction of satellite data, etc.). The NAM domain nowadays is actually quite large (see below)...so lateral boundary conditions shouldn't be an issue for most of the CONUS part of the domain for most of the integration.

I think that we've seen pretty big improvement since going to partial cycling instead of allowing the NAM to cycle on itself. I'm not in the meso-group, so I may not have this exactly right (I don't know exactly what what states they use and how far they go back for partial cycling...but basically before each analysis, the NAM is started from a previous GFS state (from 12 hrs ago all fields, not just the boundaries). Then, a series of analyses and forecasts of the NAM are run leading up to the actual initialization time, at which point the full 84 hour forecast is run (the lateral boundary conditions for this are updated using the previous GFS fcst, from 6 hours ago). I think the cycling is 3 hourly leading up to initialization time (in other words, it starts from a GFS forecast, assimilates obs, runs a short NAM forecast, assimilates more obs, runs another short NAM forecast, etc.). This allows the NAM to start from a large scale that is like the GFS, but try to resolve scales / features at its own resolution and consistent with its own dynamics. This essentially cuts off any possible "drift" in the large scale, at least relative to the GFS, since it's forced to do a complete restart from a global state very so often."

Link to comment
Share on other sites

dtk hangs out in the eastern threads--but he works out at NCEP on the GFS. He also had this info on the NAM for anyone interested:

"I don't have much to add as I'm not even sure I fully understand why the NAM had (still has?) a drift in the large scale (though there are various hypotheses related to the model itself, various DA aspects including bias correction of satellite data, etc.). The NAM domain nowadays is actually quite large (see below)...so lateral boundary conditions shouldn't be an issue for most of the CONUS part of the domain for most of the integration.

I think that we've seen pretty big improvement since going to partial cycling instead of allowing the NAM to cycle on itself. I'm not in the meso-group, so I may not have this exactly right (I don't know exactly what what states they use and how far they go back for partial cycling...but basically before each analysis, the NAM is started from a previous GFS state (from 12 hrs ago all fields, not just the boundaries). Then, a series of analyses and forecasts of the NAM are run leading up to the actual initialization time, at which point the full 84 hour forecast is run (the lateral boundary conditions for this are updated using the previous GFS fcst, from 6 hours ago). I think the cycling is 3 hourly leading up to initialization time (in other words, it starts from a GFS forecast, assimilates obs, runs a short NAM forecast, assimilates more obs, runs another short NAM forecast, etc.). This allows the NAM to start from a large scale that is like the GFS, but try to resolve scales / features at its own resolution and consistent with its own dynamics. This essentially cuts off any possible "drift" in the large scale, at least relative to the GFS, since it's forced to do a complete restart from a global state very so often."

Much more detailed and informative than I could have provided. But backs up my point that all runs start from a forecast and assimilate data to nudge the forecast towards reality, it's just that the 00z/12z runs have more data to assimilate.

Link to comment
Share on other sites

You seen the 18z uk at 72 yet? Low at 72hr is over the norther ga, eastern tenn, and the western carlinas...

actually i didn't know it went to 72 at 18z...so correction, i have not seen that. I posted the 60hr

edit...actually it's not that far off the 12z... i think our minds are playing tricks on us after seeing the gfs and nam get shoved out to sea lol

Link to comment
Share on other sites

we need that 5h to capture the low to keep it from escaping but it can't do that because the piece behind isn't allowing it to go neg tilt

As said a day or two ago need that system dropping out of Canada to drop in further west and deeper. That however could screw you as well as the storm would probably bomb over Ohio heading due north. Really a tight squeeze.

Link to comment
Share on other sites

JB: I like track inside hatteras, right to near acy and then northeast. Heavy backlash should make this DC to BWI heaviest snow.. after rain.

Anyone care to spell that out for me in regards to where he thinks the track will go. ACy? BWII?

Didnt he say it was going end up way west yesterday?

acy...atlantic city

bwii...balt

Link to comment
Share on other sites

JB: I like track inside hatteras, right to near acy and then northeast. Heavy backlash should make this DC to BWI heaviest snow.. after rain.

Anyone care to spell that out for me in regards to where he thinks the track will go. ACy? BWII?

According to his blog on accuwx pro he hasn't updated since this morning. He updated before 12z and hasn't updated since.

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...