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Global guidance continues to suggest a low amplitude phase along the west coast and a deepening trough ejecting into the plains sometime on the 28th as some sort of Colorado Low taking the classic track from CO then curving NE into the northern plains. Teleconnections are weak on this, but it does seem probable a storm will emerge the Rockies...and the GOM will be wide open with significant moist fluxes. All global guidance also suggests significant room for growth in the height field...so it doesn't seem probable anything ejecting will be squashed by the northern stream.

Big differences come in terms of latitude of the ejecting trough. ECMWF would eject the upper lead anomaly near the Panhandles of TX/OK while CMC/GFS/UKMET suggest a northern CO ejection. Makes a rather huge difference both in terms of rapid intensification, GOM feed (farther S would suggest greater moisture transport), how fast the cyclone occludes, etc. Resultant differences equate to a historic storm across southern MN (12z ECMWF) to a significant storm across portions of N MN and Nodak (0z CMC), 0z GFS somewhere in the middle.

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12 Euro verbatim would probably be a sig-svr event somewhere from the Central/Southern Plains eastward through the Mid South/Mid MS Valley/OH Valley/TN Valley and the 00z GFS is close to it.

Yeah it would, really the globals are not that different on configuration aloft...they differ much more on latitude of ejection and to a degree tilt. ECMWF would be an extreme solution obviously both due to its far S latitude and its strong negative tilt.

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would there be a possible ice storm with this or just rain in the warm sector & snow on the cold side?

Depends. Ice verbatim would be an unlikely event given the vigorous warm sector advection. It would be difficult to support any freezing layers near the surface...especially with the cruddy snow pack. Plain rain would be a bigger worry across the warm sector with this type of cyclone.

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Honestly I won't complain about anything tonite. Increasing threat somebody gets shellacked with a major CO Low. Honestly there is no way to be sure about any track as it will be highly dependent upon the lead anomaly...no different than any other leeside cyclogenesis event. The potential is high though.

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Keep in mind that there is still plenty of time for this to trend south as well, which as baro mentioned, would heighten the potential even more for not just a major storm, but a monster/historic storm (and a possible significant svr wx threat on the warm sector side). Considering the amount of upper/mid level energy likely to be digging/phasing into this feature, this scenario remains entirely plausible, I would have to think.

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Keep in mind that there is still plenty of time for this to trend south as well, which as baro mentioned, would heighten the potential even more for not just a major storm, but a monster/historic storm (and a possible significant svr wx threat on the warm sector side). Considering the amount of upper/mid level energy likely to be digging/phasing into this feature, this scenario remains entirely plausible, I would have to think.

Storm systems with a lot of upper-level energy can often trend southward as we approach "go time"... but I'd watch just how early on in the storm system's life cycle occlusion occurs. The surface pressure falls that help keep low-level winds backed (low-level shear and convergence necessity there) will often shift away from the warm sector once a cyclone occludes... and the warm front also detaches itself from the low... which then halts its northward progress. This is probably not a case where the northward progression of the warm front is in question for a potential severe risk, especially for the Lower Mississippi Valley... but if the cyclone occludes too soon, low-level winds may have a veering tendency on a synoptic level through the warm sector, and that can reduce low-level directional shear and low-level convergence. We've had what would otherwise be high-end tornado days bust horribly because of that. The less wrapped up the upper-level system is when it ejects into the Plains, the slower any occlusion will be to occur.

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SPC going pretty conservative in the Day 4-8:

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0351 AM CST FRI FEB 24 2012

VALID 271200Z - 031200Z

...DISCUSSION...

HIGH-AMPLITUDE SHORTWAVE TROUGH SHOULD EVOLVE OVER W COAST STATES BY

START OF PERIOD...FROM PHASING OF SEVERAL VORTICITY FIELDS

ASSOCIATED WITH TROUGHS NOW OVER N-CENTRAL/NERN PAC. THOUGH

DIFFERING IN AMPLITUDE...MREF MEMBERS AND OPERATIONAL

SPECTRAL/ECMWF/UKMET ARE MOSTLY CONSISTENT WITH TIMING OF 500-MB

WAVE AND ACCOMPANYING DEEP SFC CYCLONE MOVING ENEWD FROM CENTRAL

HIGH PLAINS TOWARD UPPER MS VALLEY DAY-5/28TH-29TH. PRIOR/STG FROPA

WILL RESTRICT MOISTURE RECOVERY/RETURN INTO THIS SYSTEM...THOUGH SFC

DEW POINTS 50S F MAY REACH MOST KINEMATICALLY FAVORABLE AREAS NEAR

SFC LOW.

MOISTURE IS PRIMARY UNCERTAINTY PRECLUDING CATEGORICAL/30% SVR AREA

WITH THIS SYSTEM ATTM...THOUGH AT LEAST SOME SVR CERTAINLY APPEARS

POSSIBLE GIVEN STRENGTH OF DEEP-LAYER FLOW LIKELY OVER CORN BELT AND

LOWER MO VALLEY. EML/CAPPING TYPICALLY STRENGTHENS WITH SWD EXTENT

IN THESE PATTERNS...WHILE FRONTAL/DRYLINE CONVERGENCE

DECREASES...OFFSETTING FAVORABLY HIGHER LOW-LEVEL MOISTURE. AS A

RESULT...KS/OK SVR THREAT ALSO APPEARS TOO UNCERTAIN FOR CATEGORICAL

AREA ATTM. AFTER DAY-5...POTENTIAL IS TOO CONDITIONAL FOR OUTLOOK

GIVEN FROPA ASSOCIATED WITH DAY-5 SYSTEM AND SUBSEQUENT VARIABILITY

IN PROGS OF UPPER WAVES.

..EDWARDS.. 02/24/2012

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