Jump to content
  • Member Statistics

    17,583
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

Mid to Long Term Discussion 2020


jburns
 Share

Recommended Posts

26 minutes ago, Grayman said:

Can someone explain to a newbie if the MJO forecast Moving to 7 accurate or is it like everything else that changes?  Sorry for the dumb question 

It’s just another forecast tool. They can change daily, their forecast. As best as I understand, phases 1,2,8, and now 7, per Webber, are our coldest phases for E and SE in winter months

Link to comment
Share on other sites

3 hours ago, SnowNiner said:

I really hope the MJO doesn't stall out in phase 7, and start back to loop around. 

 

1 hour ago, Grayman said:

Can someone explain to a newbie if the MJO forecast Moving to 7 accurate or is it like everything else that changes?  Sorry for the dumb question 

Those MJO plots tend to have that hook on the end.  Here are stats from DonSutherland - "Historic experience with the MJO following its reaching Phase 4 at an amplitude of 1.500 or above during the January 5-20 period (as occurred recently) sees the MJO progress into Phases 7 and 8 (88% cases)"

What I suspect we will see is something along the lines of the CFS, minus the hook on the end...that is, into Phase 5 at high amp, into Phase 6 at moderate amp, into Phase 7 at low to moderate amp, into Phase 8 at low to moderate amp, and into Phase 1 at low amp.

x11pGD0.gif 

The bigger question is will the atmosphere respond to the MJO tropical forcing in a manner that is consistent with prior cases.  It doesn't always respond (just look at last Februrary).  The MJO Seasonal Cycle tool from Paul Roundy is really good at showing the typical pattern produced by the MJO Phase and time of year - http://www.atmos.albany.edu/facstaff/roundy/waves/rmmcyc/index200reg.html

  • Like 3
Link to comment
Share on other sites

9 minutes ago, griteater said:

 

Those MJO plots tend to have that hook on the end.  Here are stats from DonSutherland - "Historic experience with the MJO following its reaching Phase 4 at an amplitude of 1.500 or above during the January 5-20 period (as occurred recently) sees the MJO progress into Phases 7 and 8 (88% cases)"

What I suspect we will see is something along the lines of the CFS, minus the hook on the end...that is, into Phase 5 at high amp, into Phase 6 at moderate amp, into Phase 7 at low to moderate amp, into Phase 8 at low to moderate amp, and into Phase 1 at low amp.

x11pGD0.gif 

The bigger question is will the atmosphere respond to the MJO tropical forcing in a manner that is consistent with prior cases.  It doesn't always respond (just look at last Februrary).  The MJO Seasonal Cycle tool from Paul Roundy is really good at showing the typical pattern produced by the MJO Phase and time of year - http://www.atmos.albany.edu/facstaff/roundy/waves/rmmcyc/index200reg.html

Grit, 

Great stuff.  Question, are the MJO plots/forecast based on ops/ensembles model data or actual obs?   Reason I ask is that you referenced last Feb.  I don’t recall the models giving us a sniff last Feb. or is my memory flawed?    

Link to comment
Share on other sites

31 minutes ago, Upstate Tiger said:

Grit, 

Great stuff.  Question, are the MJO plots/forecast based on ops/ensembles model data or actual obs?   Reason I ask is that you referenced last Feb.  I don’t recall the models giving us a sniff last Feb. or is my memory flawed?    

So the forecast MJO RMM plots are based on forecasts of tropical variables, typically OLR (clouds/convection), 850mb winds, and 200mb winds.  Sometimes VP (upper level divergence) is substituted, or included along with, OLR.

As for last winter, the MJO made a run thru Phase 4-5-6-7-8-1-2 in late Jan thru Feb, but we ended up with a La Nina-like -PNA pattern (i.e. we certainly don't always see the expected atmospheric response to the tropical forcing)

7uBcFCs.png

  • Like 1
Link to comment
Share on other sites

2 minutes ago, griteater said:

So the forecast MJO RMM plots are based on forecasts of tropical variables, typically OLR (clouds/convection), 850mb winds, and 200mb winds.  Sometimes VP (upper level divergence) is substituted, or included along with, OLR.

As for last winter, the MJO made a run thru Phase 4-5-6-7-8-1 in late Jan thru Feb, but we ended up with a -PNA pattern (i.e. we certainly don't always see the expected atmospheric response to the tropical forcing)

7uBcFCs.png

Awesome!  Thanks for clarifying   

Link to comment
Share on other sites

4 minutes ago, Waiting on snow said:

What a damn dumpster fire verbatim. Cold is gone completely. Only 2 nights even get down to freezing. And just barely.

When major pattern changes are in the works, the models flip flop a lot, so hopefully just a blip, like Clemsons’ 35 game win streak, that’s about to be ended!:gun_bandana:

  • Haha 2
Link to comment
Share on other sites

7 minutes ago, Waiting on snow said:

What a damn dumpster fire verbatim. Cold is gone completely. Only 2 nights even get down to freezing. And just barely.

Seen this movie before - major changes telegraphed in the LR - then when it gets to the timeframe modeled - the pattern of persistence is the one that wins out - hope I am wrong but just seen this too many times before. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...