Jump to content
  • Member Statistics

    18,583
    Total Members
    7,904
    Most Online
    masonj4
    Newest Member
    masonj4
    Joined

January 24-26: Miracle or Mirage Thread 2


mappy
 Share

Recommended Posts

I can't help myself - I'm watching column max temps and how they progress. Here's how they compare at HR 60 across the models that PW has with that metric. It's a good sign to me that the 3K NAM is a touch colder. People can hate on it all they want, but I've learned to not bet against 3K NAM temp profiles (good or bad) within 24-36 hours (though this is obviously outside that range).

pivotal-weather-comparison-latest.gif

  • Like 3
Link to comment
Share on other sites

Just now, mitchnick said:

Can't expect the Nam to get all thermals correct at the far reaches of its forecast period. And it's the far teaches where thermals become an important factor in final snow totals.

At the end of the 3k NAM run, it has the snow/sleet line notably south of 12k NAM in Kentucky. Maybe 50mi? fwiw 
 

NAM thermals are definitely worth watching, but like starting with tomorrows 12z or 18z?

  • Like 8
  • 100% 2
Link to comment
Share on other sites

Just now, Thrasher Fan said:

I wouldn't trust the NAM beyond 12 hours. It didn't even sample the current precip over GA correctly at initiation. 

Yes, and remember a couple days ago the Nam went hard on an appetizer (1-3") just to the south of the Metros at the end of its run for Friday, and that's Poof!

  • Like 1
Link to comment
Share on other sites

17 minutes ago, bncho said:

72 to 75 was.... weird. mix line jumped 100 miles north suddenly?

There is a closed mid level low over Missouri and the winds are screaming out of the SW at h85 and h7 so....  

For us to stay snow south of the MD/PA line we really need less phasing and a less amplified wave to our west.  The 50/50 is sliding out not locked in, the block is centered over northern Greenland, its not suppressive enough to offset a phase system that far to our west like that.  For the amplitude the NAM has we would need a more suppressive look over top.  But...even with this we can get a really nice thump snow before any mix, and the NAM could be overdoing the warming during the heavy precip some...that does happen sometimes the dynamic cooling can overcome the WAA and mix out the warm layer longer than expected...we've seen this so many times.  Dec 2013, Feb 2014, Feb 2015.  It hasn't happened as much recently because we've either been warm or cold and dry the last 9 years lol.  

It is also still possible to get a less amplified wave like the GFS and some of the EPS members show.  And frankly most of the globals are slightly less amplified also.  This primary cutting to our west was my worst case scenario 48 hours ago but I said even in that case we would still be looking at 6"+ of snow to ice...and it looks like that's holding as the worst case we've seen across guidance...which isn't a bad floor to have.  

  • Like 6
  • clap 1
Link to comment
Share on other sites

It also happened up here in March 2018 with the front running WAA snow....models had that flipping to sleet up here after only a couple inches and it stayed heavy snow through the whole WAA thump and we got about 8" before the dry slot when we got snizzle until the ULL associated stuff that got the whole area with 4-8" the next day.  

  • Like 2
Link to comment
Share on other sites

2 minutes ago, IUsedToHateCold said:

What is the E/E rule? (sorry, I haven't heard this one in my 20 years on the forum)

The NAM used be called the Eta model way back when. There was a now rather debunked theory in those days that if the Eta and Euro where in agreement, you could take that forecast to the bank.

Edit:  ninja'd :)

  • Thanks 1
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

×
×
  • Create New...