Jump to content
  • Member Statistics

    17,862
    Total Members
    7,904
    Most Online
    Malkir008
    Newest Member
    Malkir008
    Joined

Weekend Storm Discussion Part II, 2/18-2/19


stormtracker

Recommended Posts

agreed...Of course I have been saying that over and over so I am going to look pretty bad if this is "suppressed".....I think we are still seeing the models try and figure out the track....once the general idea/track is similar then the jog north usually begins....so if the 0.5" cutoff at the 12z runs or 18z runs is 50-100 mi south of DC, over the next 24-36 hours we will see that jog north through precip shield expansion and a track/strength of low adjustment.....The euro was extremely concerning though with how a formidable healthy storm system just got b-itchslapped in a period of a few hours

The starting point for the Northward jog or precip expansion needs to be where the NAM and GFS has it IMO....if it's the euro then I think a lot of us may be toast

Link to comment
Share on other sites

  • Replies 961
  • Created
  • Last Reply

i don't know if it will be at 12Z or not if at all, but we still have all day today and tomorrow to finalize the details....The Euro was a really really bad run....dry through much of VA even......we need the euro on board....

I'd like to be in the jackpot lol . The euro has pissed on us all winter with .03 and .04s...I think it's wrong this time

Link to comment
Share on other sites

agreed..if what the euro portrayed last night is realistic, we are kind of screwed though we could still back our way into a 1-3"event

Yeah....this thing is giving off the impression that any move North will not be large but very subtle....I do like the SREF probabilities for 4"+ of snow though for most of the area.....2-4" expectations should be where most of us should be sitting right now...we should have the colder air just not the precip...

Link to comment
Share on other sites

not that it matters much but my optimism was somewhat predicated on the idea that the southern stream could amplify sufficiently on its own without a phase even with confluence over New England...If we cant get hit by a storm with a negatively tilted trough and a 1000mb surface low over Birmingham then I may just be wrong.....hopefully it works itself out in our favor....I am chasing if it is going to be a miss here....

Just saw the Euro a little while ago. What strikes me is the surface low jump. As your posts went last night, everything was going great with the low going through N. Alabama into Georgia, then that low dies and the new one forms over SC and moves over Wilmington. That's when the precip shield stops its northern progression. It is a messy 500 map at that time, so I'm not sure I buy the surface depiction.

Link to comment
Share on other sites

Yeah....this thing is giving off the impression that any move North will not be large but very subtle....I do like the SREF probabilities for 4"+ of snow though for most of the area.....2-4" expectations should be where most of us should be sitting right now...we should have the colder air just not the precip...

2-4 is unacceptable with a storm this large.

Link to comment
Share on other sites

the run was goofy but the whole pattern is goofy.....I still think there is so much working against us for a high standard deviation/percentile event, but a 4-8" event isn't that uncommon or unreasonable....even 3-6"....The Euro is extremely concerning because the GFS/NAM beng where they are right now is not a bad thing.....I never extrapolate model runs and my maps are a bit coarse but Euro looked like a massive hit last night before things went wrong....I'm going to keep my mouth shut this afternoon during the run and just let it play out....Jason and I put a hex on the run....You can't screw with the euro...You have to show it respect and love and deference at all times or it will turn on you

The euro does look goofy as it has the confluence well north of us at 72 suggesting the heavier precip would get to us and then for some reason shears it almost due east. The ukmet has come north but only gives us around .40".

Link to comment
Share on other sites

the run was goofy but the whole pattern is goofy.....I still think there is so much working against us for a high standard deviation/percentile event, but a 4-8" event isn't that uncommon or unreasonable....even 3-6"....The Euro is extremely concerning because the GFS/NAM beng where they are right now is not a bad thing.....I never extrapolate model runs and my maps are a bit coarse but Euro looked like a massive hit last night before things went wrong....I'm going to keep my mouth shut this afternoon during the run and just let it play out....Jason and I put a hex on the run....You can't screw with the euro...You have to show it respect and love and deference at all times or it will turn on you

What bothers me some is that even though the GFS and NAM both still give the area a nice little snow...they both have been trending South with their 6z runs....12z needs show a jog North or at least a halt to any Southern movement for confidence levels to remain ok

Link to comment
Share on other sites

Looks like the GFS ensemble members are generally a little south of the op with the precip shield.

Being ~48 hours out, we're within the time where the Op is superior (in statistics) to the ensemble mean and the members. Perhaps dtk can comment on how true that still is since the GEFS has been updated, but until told otherwise, I'd trust the Op more than the ensembles at this junction.

Link to comment
Share on other sites

I may be delusional, but I feel like we have seen this same scenario many times over the years. The models clearly want to give us precip, so to me the massive suppression risk is low now. I am very confident in the next 24 hours we'll see the whole area get painted with .50" of precip.

I wouldn't be surprised if that didn't happen until 00z Sunday.

Link to comment
Share on other sites

09z SREF 24 hr tot precip has 0.5 QPF line right over top of DCA at 72... which basically is a hold when you compare it to the 03z SREF 24 hr tot precip at 78. Perhaps a few miles further south on 09z SREF, but basically same

Please let us know exactly how many miles farther south on the 72 hour SREF using older data. Is it 5 miles Yoda? 10? 3 blocks?

Link to comment
Share on other sites

The 0.5" line moved very little but the nrn edge shrunk considerably to the south. Either way, for the DC proper, it wasn't that noticeable of a change. it also gives rise to the notion of heavier precip just south of the nrn edge of the cutoff.

As far as the euro looking funny, it looks like at 500mb, the confluence to the north prevented the s/w trough from amplifying at hr 66 and shoved it east. You can see a weak disturbance moving into New England which actually reinforces the confluence at this time. Part of me believes the whole nrn tick in the final 48 hrs, but there has been an overall subtle trend south. It's a delicate balance between this wanting to come north and the confluence over NNE. A 50 miles shift here or there is huge. Even 30 miles.

Link to comment
Share on other sites

Being ~48 hours out, we're within the time where the Op is superior (in statistics) to the ensemble mean and the members. Perhaps dtk can comment on how true that still is since the GEFS has been updated, but until told otherwise, I'd trust the Op more than the ensembles at this junction.

Yeah and within 72 hours, on average, it's not even really close. The ensembles can still have some utility in the 48/72 hour lead time range for particularly volatile situations (where error growth is much larger than normal)....but really only to express possible outcomes and uncertainty (I wouldn't use the ensemble mean for any lead time < 3, maybe 4 days).

Link to comment
Share on other sites

Being ~48 hours out, we're within the time where the Op is superior (in statistics) to the ensemble mean and the members. Perhaps dtk can comment on how true that still is since the GEFS has been updated, but until told otherwise, I'd trust the Op more than the ensembles at this junction.

This close in I am basically just looking for a red flag with a bunch of members diverging rapidly from the op.

Don't think I have ever seen the statistics on that though. You wouldn't have a link handy by any chance?

Link to comment
Share on other sites

What are you talking about? First of all, it's an ensemble (with perturbed ICs). Secondly, the IC for 9z SREF comes from the 6z cycle of the NAM....and by the way, we do have observations at 6z.

I know, but im saying if the 12z nam wants to come north, a new complete set of upper air data and observations is there that would maybe also trend rhe 15z SREF

Link to comment
Share on other sites

I know, but im saying if the 12z nam wants to come north, a new complete set of upper air data and observations is there that would maybe also trend rhe 15z SREF

That wasn't your original post. Also, considering the fact that the SREF system is a multi-model ensemble (non of the members are the operational NAM-NMMB model), I wouldn't expect the operational NAM to "trend" toward the SREF necessarily (it can happen, to be sure). It's a completely different animal than the GEFS/GFS or ECMWF and its ensembles.

Link to comment
Share on other sites

This storm reminds me alot of Jan. 30, 2010. Maybe the setup isn't the same, it certainly is nowhere near as cold, but in that storm it was the low heights in the NE that was squashing the precip from coming north. I remember at that time, mets saying that that feature was often overmodeled. Going on memory here, so might be fuzzy. Anyway, in that storm, we didn't start seeing the north movement of the precip until within 24 hours of the event. And that movement was huge when it happened. Not saying the same thing happens here, but I can tell you that I'll be watching all the way through tomorrows runs before I jump for joy or off the bridge.

Link to comment
Share on other sites

Archived

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

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...