0Z Guidance Discussion 12/21/2010

[mitchnick]

These only go out to 120, but will be fun if the GGEM keeps up the solution:

http://collaboration...pe_gem_reg.html

look, however, at the precip backing in from the NE into Maine at the end of the 120 hrs

calling DT, DT, is there a DT in the house???

[Big O]

DT,

It sounds like you are leaning towards a more southern solution. If so and that scenario verifies does that mean NO SNOW for the northeast?

[HM]

You could be right about the MA and QPF, but I don't know about this being a "quick" storm. The onset of this storm has slowed down some, and the number of hours where precipitation is falling over the MA-to-NE is pretty significant (over 12-24 hours)

You're right. The GGEM is not a quick storm, especially in the N. Mid Atlantic. It would have to be a monster phase job like the GGEM to get that. As long as it doesn't carry everything north (the Ontario wave), then we're good. My worry is that it is taking an extreme phasing on a model run to bring appreciable snow accumulation into BWI for example. If it doesn't happen like that, it is only going to get briefer in duration and less snow.

[Dalfy]

No they are not, these are from tonight's 0z run. The GFS ens mean begins to update on RaleighWX's model page just prior to the run completing, check the time stamp...

oops my fault then. I thought 12:45 on the raleigh site was when the ensembles were updated. Thanks for the correction!

[HM]

Ok we get it...thanks

He asked

[Terpeast]

You're right. The GGEM is not a quick storm, especially in the N. Mid Atlantic. It would have to be a monster phase job like the GGEM to get that. As long as it doesn't carry everything north (the Ontario wave), then we're good. My worry is that it is taking an extreme phasing on a model run to bring appreciable snow accumulation into BWI for example. If it doesn't happen like that, it is only going to get briefer in duration and less snow.

Good point, I'll watch the ontario wave in subsequent runs, it will be interesting to see what it does. I'm thinking it would be pretty difficult to get a big phase just in time for a big one in DC especially in a nina year.

[aldie 22]

He asked

I know my bad it's just one of those things you only need to hear once.

[Guest someguy]

Wouldn't be good at all or for all?

NOT for me clown GFS map

says I get NOTHING

no snow no sleet No rain

No anything ... OF course I dont think it is right

[ace0927]

GFS Clown Maps

what is the link on earl barkers site...I cant find it...thanks

[HM]

Good point, I'll watch the ontario wave in subsequent runs, it will be interesting to see what it does. I'm thinking it would be pretty difficult to get a big phase just in time for a big one in DC especially in a nina year.

But there is always a shot at Jan 2000, right? I'll never forget that night when the rain/clouds were just plowing north and inland.

[OKpowdah]

Wes made a decent point, that due to the huge Atlantic low, we have westerlies dominating back to 65W, which may be limiting moisture convergence from the Atlantic -- a reason why model guidance has been relatively meager with QPF. Although, RH fields look very healthy ... but at this range, w/e lol

[Guest someguy]

DT,

It sounds like you are leaning towards a more southern solution. If so and that scenario verifies does that mean NO SNOW for the northeast?

iF YOU mean ALB yes

if you mean PHL or NYC NO

[Terpeast]

But there is always a shot at Jan 2000, right? I'll never forget that night when the rain/clouds were just plowing north and inland.

Right, I loved and hated that storm. Loved it because it surprised everyone, except Doug Hill on CBS who got suspicious when the storm was moving north and not OTS... none of the other TV mets caught that until it was too late! But I also hated it because I only got 9" while 15 miles to the west of me got 14-15" and another 20 miles to the east got over 18". Two heavy bands on either side of me, not moving, and a "snow hole" over my head.

[Dr No]

what is the link on earl barkers site...I cant find it...thanks

http://204.2.104.196/gfs/CONUS_GFS0P5_SFC_ACCUM-SNOW_144HR.gif

[Big O]

iF YOU mean ALB yes

if you mean PHL or NYC NO

By this you mean, Albany no snow, but PHL and NYC would see snow?

Thanks for your response by the way and keep us posted.

[HM]

Right, I loved and hated that storm. Loved it because it surprised everyone, except Doug Hill on CBS who got suspicious when the storm was moving north and not OTS... none of the other TV mets caught that until it was too late! But I also hated it because I only got 9" while 15 miles to the west of me got 14-15" and another 20 miles to the east got over 18". Two heavy bands on either side of me, not moving, and a "snow hole" over my head.

I know your pain there. I only got 6" and most of it was at around 6am with the +SN band. The rest of the storm, for me, was sleet and a lot of breaks. I was in a pretty terrible spot. Still, I'd take my chances with that type of thing again over a ridiculous Ontario "capture."

[eduggs]

take a look at the CURRENT MASSIVE 500 Low in the nw atlantic

see it?

http://www.nco.ncep....fs_500_000l.gif

96 hrs this is the 500 MB two massive 500 Lows over eastern and se Canada

http://www.nco.ncep....fs_500_096l.gif

YET according to the 0z GS this system is going to close off and BOmbs next RIGHT next to -- right next to in the synoptic large scale sense a 24 hrs later

at 120 hrs???

http://www.nco.ncep....fs_500_120l.gif

sorry I call BS

I have read your posts, rants, and articulations for years and often scratched my head as to what you mean when you make a point like the above:

Are you suggesting that

1) the GFS physics is wrong OR

2) the GFS solution is doubtful

??

Indeed I share your skepticism for many of the reasons you've stated. But I also have learned to concede that if a model of the sophistication of the GFS, Canadian, Euro etc rapidly deepen a low in proximity to another, that means it is probably physically possible. As for likelihood, I look to the ensembles and inter/intra model consistency. I believe it's impossible for any human to consistently forecast height fields at day 5 with higher skill than a weather model.

[NorthShoreWx]

LOL I think most people would be fine with a "dry slot" AFTER a foot+ of snow!

Not me. I've had so many 12 inch snows I've practically lost count (well, not really...and its true that I am not owed any more at this point), but I've also seen areas just to my east, west and south come in greater than 2 feet in some of them and don't really want to be the bridesmaid again for this one.

This pattern however is extreme. Its not like I don't normally look at 500 mb maps, but it is a change that lately its the first thing that I look at.

The affect of the current pattern on the surface weather here has been very unusual regardless of snowfall (i.e., lack thereof). We've had unusually low diurnal swings in temperature with night time temps close to normal and day time temps considerably below normal...even on the sunny days. I don't recall that happening for such an extended period during meteorological winter. The one exception/interruption this month was the rainstorm about 10 days ago.

I don't know how long this will last, but this run of the GFS only relaxes the pattern of PV / cutoffs rotating through the northeast and then retrograding into southern Canada for a day or two between Christmas and New Years before reloading with a vengence. From a snowfall pov its a powder keg, but so far all of the sparks have been damped out.

[LakeEffectKing]

BTW, though east (as expected) NOGAPS sports a nice SUB 950 LP NE of benchmark....

[Mencken_Fan]

132 hrs enalarged

http://1664596.sites...stpages/aaa.jpg

Delmarva whacked...but perhaps P-Type issues?

Repeating what I said yesterday..."Chesapeake Bay FTW".....and may repeat again tomorrow.

[Manny]

BTW, though east (as expected) NOGAPS sports a nice SUB 950 LP NE of benchmark....

Hurricane Strength ftw. That sounds ridiculous.

[Guest someguy]

I have read your posts, rants, and articulations for years and often scratched my head as to what you mean when you make a point like the above:

Are you suggesting that

1) the GFS physics is wrong OR

2) the GFS solution is doubtful

let me see if I have this right . Because you DONT a Met degree and you dont understand what I am saying ... you get to make these little snide comments ?

then you AMAZINGLY you want me to explain further ?

NO I dont think so ...

( that strategy or attacking folks you are seeking answers from working for in your life there bud?)

when I made the Post

HM granted that it was a Validf Point... so did ezweather... and so did wes

yet for some reason that is forgotten ....

Indeed I share your skepticism for many of the reasons you've stated. But I also have learned to concede that if a model of the sophistication of the GFS, Canadian, Euro ....

whoa whoa whoa!!!! ... the 12z run of the EURO does NOT show what the 0z ggem and GFS shows does it.....?

and except for the 0z dec 20 euro run NONE of the euro models have shown that massive solution...

then you state this

. As for likelihood, I look to the ensembles and inter/intra model consistency. I believe it's impossible for any human to consistently forecast height fields at day 5 with higher skill than a weather model.

all I have done in THIS thread .... in the 12z thread...... in the 0z dec 20 model thread.... is talk abourt ENSEMBLE vs Op...

somethign you stated you agree with it.

yet for some reason when I make the same point You SEEM to agree with ... it is now " incomprehensible to you???

wow that is such a shock....

[Midlo Snow Maker]

0z ukie by itself

[NorthShoreWx]

Not me. I've had so many 12 inch snows I've practically lost count (well, not really...and its true that I am not owed any more at this point), but I've also seen areas just to my east, west and south come in greater than 2 feet in some of them and don't really want to be the bridesmaid again for this one.

This pattern however is extreme. Its not like I don't normally look at 500 mb maps, but it is a change that lately its the first thing that I look at.

The affect of the current pattern on the surface weather here has been very unusual regardless of snowfall (i.e., lack thereof). We've had unusually low diurnal swings in temperature with night time temps close to normal and day time temps considerably below normal...even on the sunny days. I don't recall that happening for such an extended period during meteorological winter. The one exception/interruption this month was the rainstorm about 10 days ago.

I don't know how long this will last, but this run of the GFS only relaxes the pattern of PV / cutoffs rotating through the northeast and then retrograding into southern Canada for a day or two between Christmas and New Years before reloading with a vengence. From a snowfall pov its a powder keg, but so far all of the sparks have been damped out.

Thats not entirely correct as the block over northern Canada seems to have moved elsewhere after the Christmas weekend storm.

[LakeEffectKing]

[mitchnick]

0z ukie by itself

not often on this Board when you can find one model everybody surely hates

[GD0815]

UK OTS fwiw, I think it has been pretty much this solution for a few runs, no?

[NorthShoreWx]

not often on this Board when you can find one model everybody surely hates

Congrats Savanna.

[LakeEffectKing]

UK OTS fwiw, I think it has been pretty much this solution for a few runs, no?

Deeper with the h500 trough....Extrapolating, this would still impact SNE, IMO, but leave the MA hoping for scraps...

[baroclinic_instability]

A lot of interesting discussion and analysis here. I haven't been completely up to date on this one, but doing a quick analysis, it seems the potential for a good east coast hit seems to hinge the most on how the northern stream eventually phases with the PV Anomaly near the Gulf States. The 0Z GFS essentially treats the PV as an "ejecting" S/W trough which incites cyclogenesis ahead of the main trough which develops a strong leading edge cyclone with cold air advection turning towards the east coast as opposed to heading southward towards the GOM. The other solution favored by tonights CMC, the ECMWF, and to a degree, by the 12Z GFS, is to phase the southern PV and "absorb" it into the northern stream which then enhances the strength of CAA southward towards the GOM. This in turn develops a much deeper upper trough and eventually a much more energetic baroclinic wave up the east coast.

One thing I will say regarding the solutions is the amount of CAA all solutions develop in the low levels. It is difficult for equatorward low level cold air to suddenly shift direction and head eastward as in the 0Z GFS. It would take a sufficiently intense PV to initiate strong enough cyclogenesis to result in an eastward displacement of that low level cold air and the eventual northern cyclone the GFS develops. While the 0Z GFS certainly could be a valid solution, I find the deeper trough solutions more realistic given all model guidance have trended towards a much weaker southern stream PV Anomaly. As a result, I find a solution which results in continued CAA and a deeper developing trough more realistic then the oddball northern cyclone the GFS currently has. A weaker PV Anomaly, once phased, won't incite sufficiently strong cyclogenesis to shunt the low level CAA eastward but strong enough to enhance the continued equatorward flow of CAA, thus developing the trough deeper before ejecting the leading wave along the Gulf Stream. In terms of the GFS, the 12Z solutions seems more realistic given the circumstances. That is how I read it, at least.