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And we're off - first threat for a few mangled flakes


earthlight

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The GEFS are decent, closer to the coast than 18z, but I still am not a fan of the 12 hr accumulated precip maps. They make 0.5" liquid look dramatic. The SLP is still hundreds of miles out in the Atlantic on the mean.

That said there is clearly a nice spread west and a few bombs on there.

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Yeah the 0z GFS is definitely further south with the base of the trof. But there is an area of vorticity that slides from near Michigan to Ontario around 60-66hrs. This region remains the overall center of mid-level circulation throughout. And it seems to inhibit the structure from tilting negatively and forming a closed circulation in the mid-Atlantic. Stretching of the trof further south would make it easier to form a closed contour further south, and a semi-captured slp scenario along the coast.

Yesterday's hits had the 552dm contour in northern Ga, and eventually a closed contour in the mid-Atlantic. The 0z GFS has 552dm hundreds of miles north of there. The UK says we're close, as does several ensemble members. But I'm worried that a relatively shallow trof will remain too progressive to spin up the type of low center we need. Time of year should at least help us with the thermal gradient and natural baroclinicity. This should enhance slp deepening as soon as the s/w vorticity interacts with that gradient.

When you look at the overall synoptic setup and the mid and upper level height fields, it's remarkable that the system even gets heavy precipitation as far west as it does on the models. The height field is really not ideal for bringing the surface low pressure tucked in near the coast. It's pretty flat to start, actually, and that's why people have been saying over the past few days "why won't the h5 close off like it typically does" etc. The reason is that the shortwave dives southeast but then eastward as the height field de-amplifies. This has a good bit to do with the collapsing ridge over the Rockies and the kicker shortwave which is diving southeast from the Pac NW...the pattern is pretty fast and right on the heels of this system.

That being said...it's really interesting to see the GFS do this tonight. The main change as we both have noted is that the vorticity rolling southeast (that crosses the international border 12 hours before the frame below) does so emphatically--to a point where it reaches the GA state border. It's also interacting with second shortwave (seen below trailing the trough base over GA/MS and to the Gulf) this run, whereas this interaction was non-existent or significantly delayed on the earlier runs on 10/26.

Also, when you look at the image below...remember all of the typical upper air patterns that produced significant east coast lows. Doesn't this one seem to be a bit flat and farther north? That's because it is. It's a very, very tight window of time to get this amplified before the entire thing flattens out and the surface response escapes east by hundreds of miles.

7FTq7.png

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EL I feel the same way as you do. Nice description and visual. The models have been converging toward an impressive but ultimately flattening and progressive s/w trof. The trof characteristics and offshore slp track seemed reasonable to me based on the wavelength and position. But some of the GEFS members and now especially the UK have raised my eyebrows. We had such a good string of luck last year that I'm consciously trying to compensate for acquired overconfidence. But maybe this really could happen.

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Wouldn't be a threat without the 5000x5000 pixel GGEM map that is of such poor quality that I still can't make out what it's showing.

Its incredible they haven't changed their graphics in over a decade. Even the "improved" color maps are still dogcrap.

I remember looking at those same exact horrible black and white graphics when I was a freshmen in college in late 1999.

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Its incredible they haven't changed their graphics in over a decade. Even the "improved" color maps are still dogcrap.

I remember looking at those same exact horrible black and white graphics when I was a freshmen in college in late 1999.

It's a total joke...for the life of me I can not understand why they are still produced. Better yet, they are used as the main source of graphics for the model output.

Seriously, here it is man. The best Canadian forecast model. Base your forecast off of our latest 2011 graphics right here:

post-6-0-40884600-1319695054.png

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It's a total joke...for the life of me I can not understand why they are still produced. Better yet, they are used as the main source of graphics for the model output.

Seriously, here it is man. The best Canadian forecast model. Base your forecast off of our latest 2011 graphics right here:

post-6-0-40884600-1319695054.png

Even the ewall graphics which have been the same for like 7 years are so much better. And they are still fairly primitive.

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Even the ewall graphics which have been the same for like 7 years are so much better. And they are still fairly primitive.

All of this said I have come to accept it for what it is---I guess it adds to the experience of model watching. It will feel different when/if they change the graphics. I'm sure I'll get over it though, as I will finally be able to comprehend what the model is showing.

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All of this said I have come to accept it for what it is---I guess it adds to the experience of model watching. It will feel different when/if they change the graphics. I'm sure I'll get over it though, as I will finally be able to comprehend what the model is showing.

You eventually get used to it. I was so used to getting the ETA and AVN on the cirrus site before they had the "old" typical ncep site. The ncep site before the one we all got used to was horrible and updated later than most other sources.

When the "new" ncep site came on in 2001 it was really weird, but then it became a staple for 10 years.

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euro is impressive!

dynamic cooling ought to be at work in that setup. it's going to take a lot to overcome the boundary layer this time of year (and day on the current model progs with the precip occurring between 18 and 00z)..but if the euro track/situation verifies it could happen. the 2m temps cool pretty dramatically from 66 to 72 hours.

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dynamic cooling ought to be at work in that setup. it's going to take a lot to overcome the boundary layer this time of year (and day on the current model progs with the precip occurring between 18 and 00z)..but if the euro track/situation verifies it could happen. the 2m temps cool pretty dramatically from 66 to 72 hours.

This is a setup where even people at 500 feet would see 6-8" and the city would see very little...maybe an inch or two of slop. Obviously October is a big reason for that.

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This is a setup where even people at 500 feet would see 6-8" and the city would see very little...maybe an inch or two of slop. Obviously October is a big reason for that.

Yeah--it's a forecasting nightmare. If the Euro verifies I will be more than happy with my few inches on the grass.

Interestingly, Newark has never recorded more than 0.3" of snow in October (10/20/1952). So if this all works out we will be making history.

That's if the snow can stick on the tarmac which is still cooling down from the 108 F degree day three months ago.

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