18Z Model Thread

[Ray8002]

Some changes at Hr. 30 already compared to Hr.36 12z........

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/18/fp0_030.shtml

[PhineasC]

NAM seems even faster than 12Z which probably isn't good.

[stormtracker]

NAM seems even faster than 12Z which probably isn't good.

I think now, you want it to be a little faster and a bit farther north OR the northern stream digging more to catch the southern vort

[Joe4alb]

18z s/w looks more robust and uniform. I want to see a clean phase here, not the split like the 12z was showing.

[Joe4alb]

s/w is significantly further north at 36hrs

[TowsonWeather]

I think now, you want it to be a little faster and a bit farther north OR the northern stream digging more to catch the southern vort

Strongly agree. Ideally the latter, but at this point the former would be welcome too imo. Anything but the no-phasing mess of the 12Z suite.

[stormtracker]

Ugh...I will say this..the NAM is better looking than 12/6z..probably not enough to do what we want, but enough to sucker us back in

[Ian]

I think now, you want it to be a little faster and a bit farther north OR the northern stream digging more to catch the southern vort

having the southern wave move faster is a negative for this area at least i think unless we're back to overrunning hopes maybe. or it has been thus far. it is a bit more intense thru 36 but less diggy etc.

[Dalfy]

Yea 300 mb @ 36 looks good too energy is still diving southward where as @ 42 it had stopped...

18z @ 36

12z @ 42

[stormtracker]

having the southern wave move faster is a negative for this area at least i think unless we're back to overrunning hopes maybe. or it has been thus far. it is a bit more intense thru 36 but less diggy etc.

Definitely disagree on the less diggy. It certainly is vs the 12z (northern stream).

[Dalfy]

Hr 42.. southern energy waay north.. its alot closer IMO

BTW 300 looks ALOT better.. more digging.

[stormtracker]

Well, it looks better than 12z, but its not gonna get us what we need. It'll probably end up like the GFS solution

[Ian]

Definitely disagree on the less diggy. It certainly is vs the 12z (northern stream).

yeah well i was ref the s vort. but i think you still want that southern piece to be slower even if it looks stronger here. it takes a while to orient the flow and if it's east it's east.

[Bluescat1]

http://www.twisterdata.com/index.php?prog=forecast&model=NAM&grid=221&model_yyyy=2010&model_mm=12&model_dd=23&model_init_hh=18&fhour=48&parameter=RELV&level=500&unit=MB&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

[chris87]

improvements at 48h....better ridging ahead of the shortwaves..

look at 48h 18z vs 54h 12z at 300 mb....pretty different...

[stormtracker]

Radically different between 12z and 18z...

[Midlo Snow Maker]

[Midlo Snow Maker]

better but nah

[Wonderdog]

We're gonna have to be satisfied with baby steps at this point.

[Ian]

Certainly a step in the right direction.

slp placement is very similar to before. need s/w to be slower which isnt happening apparently.

[dg12x]

Still worse than last night's 0z run. Really would take a shocker to bring this baby back.

[SEVAsNOwSTORM]

Still worse than last night's 0z run. Really would take a shocker to bring this baby back.

Very true, but it can happen.

[Joe4alb]

Still worse than last night's 0z run. Really would take a shocker to bring this baby back.

not really, that s/w which didn't phase at all on the 12z run phases a bit to late on the 18z, but look how much further north it is. that is the key to this whole thing. if there is another jog (even a little), that will allow for yet an earlier phase, more digging and ultimately a more amplified solution. I truly don't think we are miles apart for a good result here.

[Ian]

Still worse than last night's 0z run. Really would take a shocker to bring this baby back.

i think mostly you have a slightly juiced system thx to the s/w being a bit stronger. but the northern stream is still taking its sweet time getting right to pull it north.

[goldstar]

The west trend begins with the NAM... That strung out feature is a lot more indicative of the model trying to handle the phasing right? It is pretty messy, but we can't be that off on the phasing, maybe 12 hours?

[Ian]

not really, that s/w which didn't phase at all on the 12z run phases a bit to late on the 18z, but look how much further north it is. that is the key to this whole thing. if there is another jog (even a little), that will allow for yet an earlier phase, more digging and ultimately a more amplified solution. I truly don't think we are miles apart for a good result here.

it's not further north

edit: well the s/w is obviously but that's not good -- the slp ends up basically the same as previous runs

[SBUWX23]

The west trend begins with the NAM... That strung out feature is a lot more indicative of the model trying to handle the phasing right? It is pretty messy, but we can't be that off on the phasing, maybe 12 hours?

There is no west trend on this run.

[Midlo Snow Maker]

IN THE EAST...MODEL SPREAD HAS CONTINUED TO NARROW CONCERNING THE

TRACK AND OTHER DETAILS OF A POTENTIAL WINTER STORM AFFECTING THE

EAST COAST DAYS 3-4...WITH THE MOST NOTICEABLE AND CONSISTENT

MODEL TREND OBSERVED FOR FASTER NORTHEASTWARD ACCELERATION.

EARLIER PREFERENCES WERE FOR A SCENARIO CLOSEST TO THE 06Z GFS

WHICH REPRESENTED AN AVERAGE OF THE MOST WESTWARD 00Z ECMWF AND

MORE EASTWARD 00Z GFS...WITH THE LAST SEVERAL RUNS OF THE

UKMET/CANADIAN SOUTH AND/OR EAST OF AN OTHERWISE NARROWING CLUSTER

OF GUIDANCE AND THUS WERE NOT SERIOUSLY CONSIDERED. DESPITE

IMPROVED CLUSTERING OF SOLUTIONS AND SOME CONSISTENCY IN

TRENDS...IT REMAINS PREMATURE TO PICK A SPECIFIC DETERMINISTIC

SOLUTION WITH HIGH CONFIDENCE. THE TROUGH APPROACHING THE REGION

HAS ONLY RECENTLY ENTERED THE MORE DENSELY POPULATED OBSERVATIONAL

NETWORK...AND THUS IT WILL PROBABLY TAKE ANOTHER 1 OR 2 MODEL RUNS

AT LEAST TO RESOLVE THE MULTIPLE STREAM INTERACTIONS WHICH IS

CRUCIAL TO A SUCCESSFUL FORECAST IN THIS SHORTWAVE PATTERN.

THUS...THE FINAL PRESSURES/FRONTS WERE ONLY NUDGED ABOUT MIDWAY

BETWEEN THE 06-12Z GFS...WHICH CREDITS THE NEW CONSENSUS FOR A

FASTER SOLUTION WHILE ALSO MAINTAINING CONTINUITY AS THE PRECISE

TRACK FORECAST STILL CONTAINS A LARGE AMOUNT OF UNCERTAINTY.

[IsentropicLift]

It's the Nam at long range. I'm much more interested in the improvements through 48hrs than I am the end result at this point. Were not miles away from a ECS...just a day late and a dollar short.

[Ian]

Agreed.

i edited because clearly the s/w is but i think it's wrong to think that's a positive sign overall. in this case it mostly means it's faster and with the surface reflection initially having a good deal to do with it it keeps the slp too far east. the 500 gyre takes a while to come together right so you want to delay the slp formation (in/near gom or se) as long as possible.