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Becoming more active into November


OKpowdah

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Definitely a concern, though I'm amused by the fact that the 00z ECMWF ensemble mean actually looks a lot more progressive than the operational run. Will probably take a few more days to sort out even the general evolution.

I'll take the 12z member P007 on the GFS ensemble with nachoes please.

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Huh? November is one of the most active months for tornadoes, and sometimes called the "second season" Since 2001, only the years 2003, 2007, and 2009 have escaped a notable outbreak or tornadic event of some kind during the month of November.

Well, lets say I wasn't into the severe weather quite -as- much before 2002. The Van Wert Tornado was tracking in my direction, many miles away from me. 41N latitude. I will never forget the tornado siren on that day, November 10, 2002. 17 tornadoes in IN/OH/PA (I think.)

http://www.greatlakes.salsite.com/SevereStorms/Nov_10_to_12_2002/spc/tornado_paths_graphic.gif

Now I live in a place that can't get a 55 dew point in November.

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18Z ECMWF is a few days slower with the system. Based on afternoon water vapor analysis of the North Pacific and North America...this pattern makes a little more sense. I would favor the deeper solution offered by the GFS with a slower and further south track like the euro.

Not sure that would be favorable considering all that time is going to allow the ridge to amplify, potentially significantly, and decrease the progressiveness of the pattern, in addition to allowing the trough to become disjointed/strung out positively tilted as the 12z models suggested.

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Except you have moisture built up across the area for several days prior as well.

Not that it matters nine days out on an outlier solution, but I've observed that trajectories matter even when moisture return commences well ahead of time. If you have continental air recirculating in from the east coast, you'll just end up with moisture holes advecting through the warm sector and see more issues with mixing out during the day. Seems this has happened a couple times this year, though I can't recall specific dates. That being said, the H85 trajectories (eyeballing from instantaneous vectors) actually look pretty good on that 216-hr. panel, on second glance. So much for any attempt at a consensus on timing -- though at least we have a temporary consensus that it kicks out in some fashion.

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DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0301 AM CDT SAT NOV 03 2012

VALID 061200Z - 111200Z

...DISCUSSION...

A PATTERN SHIFT WILL OCCUR THIS OUTLOOK PERIOD...SHIFTING FROM AN

ERN TROUGH/WRN RIDGE TO A WRN TROUGH/ERN RIDGE. HOWEVER...THE THREAT

OF SEVERE WEATHER APPEARS MINIMAL AT THIS TIME.

AN ERN TROUGH WILL REMAIN D4-D5...AND WILL EXIT THE COAST IN THE

D6-D7 TIME FRAME. THIS WILL MAINTAIN GENERALLY COOL AND STABLE

CONDITIONS FOR THE ERN HALF OF THE CONUS.

BY D7 AND D8...A LARGE UPPER TROUGH IS FORECAST TO AMPLIFY ACROSS

THE WRN STATES...AND GRADUALLY SHIFT EWD. THIS WILL CAUSE WARM HUMID

AIR TO STREAM NWD ACROSS THE PLAINS. THE GFS BRINGS THE TROUGH EWD

INTO THE PLAINS ON D8 WITH A DEEP SURFACE LOW...SUGGESTING SEVERE

WEATHER FROM OK INTO SRN MN. HOWEVER...THE ECMWF KEEPS THE TROUGH

FARTHER W. EVEN WITH THE FASTER GFS SOLUTION...INSTABILITY IS LIKELY

TO BE LIMITED.

SEVERE WEATHER COULD BE DENOTED IN FUTURE OUTLOOKS ONCE

PREDICTABILITY OF THE TROUGH INCREASES.

..JEWELL.. 11/03/2012

SPC catching on a bit, although trusting the GFS when it comes to instability/thermodynamic fields this far out is a bit of a dangerous game to be playing, especially when Jewell mentions a warm, humid air mass being in place in front of the trough, which is reasonably supported by 00z guidance.

And then mentions that severe outlooks are possible immediately after that, so kind of a confusing discussion. That is a large area he outlines on D8, larger than I actually thought would be discussed.

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Obviously several days out, but it looks meh... Chasers getting excited over nothing once again.

There, I said it.

I'm sure I'd feel that way about most setups too if they were usually a 10-hour haul each way for me. guitar.gif

In all seriousness, I'd give it a 20-25% chance of becoming something worthwhile at this range. It would truly be "meh" if it were June or even April, but it's a better-looking opportunity than you'll see most Novembers in the Plains and Midwest.

The 12z ECMWF continued to look more consolidated and neutral-tilt, but I imagine moisture would be a significant problem, since it also amplifies the leading (Nor'easter) system and lingers it right off the East Coast. The farthest out I can see surface fields is H+180, and at that point streamlines look downright ugly.

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the big thing coming up with this pattern is going to be the start of the upslope snow season for the rockies. by mid-to-late week, as i see the models, you're looking at a decent 6-12+" event for western Montana, southern/central Alberta, and even into the Cypress Hills in Saskatchewan. and that's before all the fun happens in the southeastern prairies and the plains on the weekend. The only thing that would me missing from such an event is a playoff football game in Calgary (Stampeders are playing on the road in Toronto).

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At first the glance, the 00z GFS appears quite disjointed, however, the southern vort max looks to be separating itself and becoming a formidable system of its' own, with secondary surface cyclogenesis. That said, I'm not liking this GFS verbatim in that the ridge is further west/more amplified than the 12z/18z verbatim and the nor'easter takes longer to get the heck out of there, thus the trough gets disjointed because of the less progressive pattern and moisture return becomes limited for a time.

usavrthgtgrd500mb159.gif

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I'm starting to lose hope for this one. In mid-November, you really need the stars to align in terms of moisture return. That typically means an extended period of antecedent broad ridging over the entire eastern US. The trough responsible for the nor'easter this coming week will do us no favors, as the Gulf takes a beating by Wed. Much as is the case in March and early April, it's the time of year when you probably want to give it several days, if not a week, to recover before moisture return even begins. The surface dew points showing up on the GFS and ECMWF -- largely upper 50s with some lower 60s -- aren't going to cut it for a high-end threat. I wouldn't be surprised to see a cap bust Saturday owing to lack of moisture, except up north along the surging cold front. Sunday will almost certainly see convection along the front, but most likely linear mode, with some QLCS threat over the Ozarks and surrounding regions.

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That typically means an extended period of antecedent broad ridging over the entire eastern US. The trough responsible for the nor'easter this coming week will do us no favors, as the Gulf takes a beating by Wed.

Yeah, that thing needs to lift out faster to have more confidence in this.

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