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Winter 2011-2012 Kickoff Thread | December 2011


earthlight

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Agree, 5-10 isn't bad, I'm mostly referrencing D 10 and beyond, verification scores really fall off.

I generally agree about the OP runs past day 5 on the pattern. But the ensembles are more useful at this range still.The AK vortex shows up 6-10 day Euro ensemble mean:

And it isn't like there is no reason to believe this solution, MJO although generally weak is forecast by Euro and other stall out phases 4/5 next week:

http://www.cpc.ncep....IVAR/ecmf.shtml

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Agree, 5-10 isn't bad, I'm mostly referrencing D 10 and beyond, verification scores really fall off.

I agree. I am not even sure why they bother running the GFS past 240 hrs. I would run it twice a day

through 240 at the same resolution for all hours. I would only do a 6z and 18z through 120 hrs since

those off hour runs are much more helpful over the short term.

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So focus on 120 hours and under then? Good advice that has been given many times in the past and rarely heeded. Why anyone would fret over the 11-15 day period on any ensemble mean is simply madness. I think this group is quite savvy and gets this, but there are many who don't and waste precious time hand wringing over something that none of us have control over to begin with......Let's not define insanity as a collective group, yeah?

Cheers

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It has to cool off first though. Down to 33 but its not as if temps are plummeting.

On a north wind with CAA, the cold air funnels down the Hudson seemingly unimpeded. It is definitely the best surface flow for keeping a cold air mass entrenched in NYC. Much of Quebec is below zero and that is our source region - of course we won't see it that low, but struggling to reach 30 tomorrow and remaining in the 20's is not a stretch to believe, even in the city.

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0z nam keeps the area in the upper 20's and low 30's all day tomorrow. Shows it never getting above freezing all day.

Soundings have a 1pm temp of 28 degrees in NYC.

That's starting to sound a bit too cold... the models do seem to have a slight cold temperature bias with cold spells, and this is probably another one of them, but it's odd how the models keep trending colder for tomorrow despite the fact that it's within the 24 hour range.

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That's starting to sound a bit too cold... the models do seem to have a slight cold temperature bias with cold spells, and this is probably another one of them, but it's odd how the models keep trending colder for tomorrow despite the fact that it's within the 24 hour range.

Several cool shots this season have over performed. Even today was a few degrees below the forecast. I can see the NAM verifying.

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Several cool shots this season have over performed. Even today was a few degrees below the forecast. I can see the NAM verifying.

Interestingly even the GFS isn't as cold as the NAM, although they're still close. Either way, whether it's 30 or 33 degrees tomorrow, it's going to be the coldest day we've seen so far.

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Interestingly even the GFS isn't as cold as the NAM, although they're still close. Either way, whether it's 30 or 33 degrees tomorrow, it's going to be the coldest day we've seen so far.

An enthusiastic junior high school earth science student could likely forecast next day 2 meter temps with greater precision than the GFS...

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An enthusiastic junior high school earth science student could likely forecast next day 2 meter temps with greater precision than the GFS...

The specific 2m temps on the GFS definitely aren't very reliable. I actually find myself a lot of the time automatically correcting the GFS temperatures in my head when looking at the run.

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I think the post-Christmas storm will be the one to watch. Not saying the storm on X-mas Eve can not happen, but I like the set-up better for X-mas day w/ cold air in place and a more favorable PNA

JB in his latest blog said watch out for a big east coast storm somewhere between Christmas and New Years.

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0z GEFS mean has a signal for a storm on the 26th.

Wouldn't it be something if we could manage a boxing day storm in this crappy december. I wouldn't on it, but if there's a period to produce its Christmas-New Years as the PNA ridge orients itself in the Western US. Much more favorable position than earlier this month, especially if we can get the axis over to ID.

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Wouldn't it be something if we could manage a boxing day storm in this crappy december. I wouldn't on it, but if there's a period to produce its Christmas-New Years as the PNA ridge orients itself in the Western US. Much more favorable position than earlier this month, especially if we can get the axis over to ID.

I wouldn't rule out the system on the 23rd quite yet. I know the models seem to be shearing this thing out but I could see this trending slightly stronger. In fact, the new 00z ECMWF is trickling in with some N. Mid Atlantic -SN this run.

Having said that, I do agree that the PNA driven period will be active with something lining up after Christmas. The only thing I will warn about this period will be the potential for mixing/changing over, perhaps even all rain. Despite the cold source and awesome PNA signal, no blocking will likely leave us with poorly placed high pressures.

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I wouldn't rule out the system on the 23rd quite yet. I know the models seem to be shearing this thing out but I could see this trending slightly stronger. In fact, the new 00z ECMWF is trickling in with some N. Mid Atlantic -SN this run.

Having said that, I do agree that the PNA driven period will be active with something lining up after Christmas. The only thing I will warn about this period will be the potential for mixing/changing over, perhaps even all rain. Despite the cold source and awesome PNA signal, no blocking will likely leave us with poorly placed high pressures.

there's def. a signal for a storm around the 26-28th period. The euro hangs back some southern stream energy so we dont get a phase but the potential is there with the ridge out west amplifying the trough. Bad thing is there is no blocking so it can cut inland

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there's def. a signal for a storm around the 26-28th period. The euro hangs back some southern stream energy so we dont get a phase but the potential is there with the ridge out west amplifying the trough. Bad thing is there is no blocking so it can cut inland

The 12/22-23 system has a good orientation with the upstream high pressure / cold air in place along with the baroclinic zone along the coast. If this southern s/w doesn't shear out like the models are currently suggesting, this will become a coastal storm with accumulating snow. My worry with the system on the 26th will be the fast speed, lack of upstream high pressure and cold air that can easily erode should the track of the system call for it. A lot would have to come together just right with a system like that (same ordeal happened with 12/7).

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The 12/22-23 system has a good orientation with the upstream high pressure / cold air in place along with the baroclinic zone along the coast. If this southern s/w doesn't shear out like the models are currently suggesting, this will become a coastal storm with accumulating snow. My worry with the system on the 26th will be the fast speed, lack of upstream high pressure and cold air that can easily erode should the track of the system call for it. A lot would have to come together just right with a system like that (same ordeal happened with 12/7).

For those who like to use the NOGAPS theory, its interesting to note it may be the least progressive with that 12/23 event of all the models.

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