prinsburg_wx Posted February 6, 2013 Share Posted February 6, 2013 Significant winter storm expected to develop on saturday in se CO and move ne to the Northern Great Lakes area on monday. Still some timing/strength differences but most models are in agreement with the track of the storm with heavy snow & wind for parts of Nebraska ne to n Wisconsin. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 6, 2013 Share Posted February 6, 2013 I am not ready to jump on the bandwagon yet...at least in terms of a major winter storm. The potential exists for something decent, but both the chance for northern stream interference and the relatively high amplitude shortwave ridge ahead of the cutoff anomaly suggest thermals will be marginal except deep into the cold sector. Someone on the edge may get a sloppy mess of rain/snow. That said, probably the best threat in ages for much of the plains and portions of the Front Range. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 6, 2013 Author Share Posted February 6, 2013 I am not ready to jump on the bandwagon yet...at least in terms of a major winter storm. The potential exists for something decent, but both the chance for northern stream interference and the relatively high amplitude shortwave ridge ahead of the cutoff anomaly suggest thermals will be marginal except deep into the cold sector. Someone on the edge may get a sloppy mess of rain/snow. That said, probably the best threat in ages for much of the plains and portions of the Front Range. I shouldn't have worded it as "major" but it could be a significant storm for a large area, especially in terms of moisture...i don't think Nebraska has had anything worth a damn all winter. Right now, it looks like w/nc NE, e SD & wc/n MN has the best shot of the heaviest snow...mix cocktail for my area and rain se MN. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 7, 2013 Share Posted February 7, 2013 I shouldn't have worded it as "major" but it could be a significant storm for a large area, especially in terms of moisture...i don't think Nebraska has had anything worth a damn all winter. Right now, it looks like w/nc NE, e SD & wc/n MN has the best shot of the heaviest snow...mix cocktail for my area and rain se MN. Latest 00z GFS does not look bad...still a bit warm for you but would be an impressive event for portions of the High Plains into SD and ND. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 Latest 00z GFS does not look bad...still a bit warm for you but would be an impressive event for portions of the High Plains into SD and ND. Yeah, i'm riding the gfs on this storm even though i most likely miss a all snow event...0z CMC finally catching a clue but its still se of the GFS. Link to comment Share on other sites More sharing options...
ZackH Posted February 7, 2013 Share Posted February 7, 2013 Latest model suites keep shifting north. Starting to get interesting for us here in Grand Forks if these trends stay consistent. The deformation band looks to be a little unrealistically far away to the NW though at this point. Still, something to follow! Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 7, 2013 Share Posted February 7, 2013 Latest model suites keep shifting north. Starting to get interesting for us here in Grand Forks if these trends stay consistent. The deformation band looks to be a little unrealistically far away to the NW though at this point. Still, something to follow! I tend to agree. Deep PV ejection fro the Rockies almost always favor a farther S track than the models prog due to poor handling on terrain influences on PV stretching. That said, this is the first decent CO Low/leeside ejection we have seen all winter for the Northern Plains/High Plains. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 7, 2013 Share Posted February 7, 2013 12z CMC has all sorts of northern stream interference and shunts the low way S and E over the Twin Cities. Interesting. Doesn't seem very plausible. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 12z CMC has all sorts of northern stream interference and shunts the low way S and E over the Twin Cities. Interesting. Doesn't seem very plausible. I see the 12z ukie is even further s of the cmc at 96hr...L in sw WI Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 12z GFS ensembles at hr 84 Link to comment Share on other sites More sharing options...
ZackH Posted February 7, 2013 Share Posted February 7, 2013 I tend to agree. Deep PV ejection fro the Rockies almost always favor a farther S track than the models prog due to poor handling on terrain influences on PV stretching. That said, this is the first decent CO Low/leeside ejection we have seen all winter for the Northern Plains/High Plains. It seems as if the northward trend has coincided with the models picking up on the development of the Nor'easter, though. I think that the Nor'easter really bombing out and stalling/looping (by some of the models) up there in the NE is bringing the northern plains system further north and west also. The Nor'easter seems to be helping to amplify the pattern perhaps... steering our system further north. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 Updated HPC Snow Probs for Day 3 Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 7, 2013 Share Posted February 7, 2013 It seems as if the northward trend has coincided with the models picking up on the development of the Nor'easter, though. I think that the Nor'easter really bombing out and stalling/looping (by some of the models) up there in the NE is bringing the northern plains system further north and west also. The Nor'easter seems to be helping to amplify the pattern perhaps... steering our system further north. I guess I will have to respectively disagree with you. EC bomb has been sufficiently well modeled for days now, the synoptic evolution of the ejecting PV anomaly is likely driven more by northern stream interaction. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 I guess I will have to respectively disagree with you. EC bomb has been sufficiently well modeled for days now, the synoptic evolution of the ejecting PV anomaly is likely driven more by northern stream interaction. MPX already issuing winter storm watches for my area...they also seem to think the EC bomb could affect the track of the weekend storm. AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 232 PM CST THU FEB 7 2013 .DISCUSSION... THE MAIN FORECAST ISSUE IS OBVIOUSLY THE POTENTIAL FOR A SIGNIFICANT WINTER STORM ACROSS THE AREA OVER THE SECOND HALF OF THE WEEKEND. LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE FEATURE OF INTEREST MOVING INTO THE WEST COAST AT THE CURRENT TIME. THE OTHER FEATURES OF INTEREST IN THE BIG PICTURE ARE THE UPPER WAVE CURRENTLY MOVING THROUGH OUR AREA... WHICH IS HELPING TO GENERATE A SWATH OF PCPN OFF TO OUR SOUTHEAST... AND THE SOUTHERN STREAM WAVE MOVING ALONG THE GULF COAST. THESE TWO UPPER WAVES WILL PHASE OFF THE MID-ATLANTIC COAST AND CREATE A BLOCKBUSTER OF A WINTER STORM FOR FOLKS IN NEW ENGLAND OVER THE NEXT 48 HOURS. THE EVOLUTION OF THAT SYSTEM WILL IMPACT HOW THE WESTERN SHORTWAVE BEHAVES AS IT EJECTS NORTHEAST INTO OUR AREA OVER THE LATTER HALF OF THE WEEKEND. THE DEGREE TO WHICH THE EASTERN STORM BOTTLES UP THE FLOW WILL HELP DICTATE THE TRACK AND AMPLITUDE OF THE UPPER PATTERN AHEAD OF OUR SYSTEM... WHICH IS LIKELY PART OF WHY WE/RE STILL SEEING A SIGNIFICANT AMOUNT OF SPREAD IN THE GUIDANCE AS TO HOW THINGS WILL UNFOLD ACROSS OUR AREA. THE NAM AND GFS ARE FARTHEST WEST... ALONG WITH THE SREF... WHILE THE ECMWF... GEM... AND FIM ARE FARTHER EAST. AT THIS POINT... THE CONSENSUS OF THE GUIDANCE IS FAIRLY CLOSE TO THE ECMWF EVOLUTION... SO WILL STICK SOMEWHAT CLOSE TO THAT WHILE ALLOWING FOR A BIT MORE WARMING IN THE LOW LEVEL THERMAL PROFILES IN ACCORDANCE WITH WHAT THE NAM AND GFS SUGGEST TO SOME EXTENT. THIS WOULD CONTINUE TO SUGGEST A MIXED PCPN EVENT FOR A GOOD PART OF THE AREA... WITH THE NORTH AND NORTHWEST PORTION OF THE AREA HAVING THE GREATEST LIKELIHOOD OF REMAINING ALL SNOW. WITH THAT IN MIND... WILL BE ISSUING A WINTER STORM WATCH THAT INCLUDES THE NORTHERN AND WESTERN PORTION OF THE AREA FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT. IT IS POSSIBLE THAT THE WATCH MAY NEED TO BE EXTENDED SOUTH/EAST IN AREA DEPENDING UPON HOW EXPECTATIONS EVOLVE... BUT FOR NOW DECIDED TO FOCUS ON WHERE CONFIDENCE IS HIGHEST THAT 6-8 INCHES OR MORE OF SNOW WILL OCCUR... ALONG WITH STRONG WINDS. Link to comment Share on other sites More sharing options...
ZackH Posted February 7, 2013 Share Posted February 7, 2013 I guess I will have to respectively disagree with you. EC bomb has been sufficiently well modeled for days now, the synoptic evolution of the ejecting PV anomaly is likely driven more by northern stream interaction. Disagreeing is fine! And you have way more experience than me in your career and especially in this region. I am more just postulating on possible reasons for the northern trend in the American models... just possibilities that were running through my head, thinking out loud almost. Link to comment Share on other sites More sharing options...
skowee Posted February 7, 2013 Share Posted February 7, 2013 Not sure how many of you guys remember this storm [it links to NWS Grand Forks news article]. Now back to the present - Rapid City, Aberdeen, and Chanahassen have posted watches as of this afternoon. The storm from last year indicated at about this far out that most of eastern North Dakota was going to get walloped with 12"+ of snow. In the storm totals map we see that the heaviest snow was confined to SE ND, NE SD, and western MN. I bet the folks at FGF are holding back for another 12-24 hours or so just to make sure the models don't flip-flop-and flip again on them like they did in February 2012. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 7, 2013 Author Share Posted February 7, 2013 Not sure how many of you guys remember this storm [it links to NWS Grand Forks news article]. Now back to the present - Rapid City, Aberdeen, and Chanahassen have posted watches as of this afternoon. The storm from last year indicated at about this far out that most of eastern North Dakota was going to get walloped with 12"+ of snow. In the storm totals map we see that the heaviest snow was confined to SE ND, NE SD, and western MN. I bet the folks at FGF are holding back for another 12-24 hours or so just to make sure the models don't flip-flop-and flip again on them like they did in February 2012. I remember that storm...got 6" from it and was the biggest storm of the 2011-2012 season for my area. Link to comment Share on other sites More sharing options...
Chinook Posted February 7, 2013 Share Posted February 7, 2013 I will be wishing you guys more luck than me on this system. Looks like there will be some chance of freezing rain accumulation in SD and MN. There's also a chance for over 1.2" of liquid equivalent in the snow area. Even if that GFS QPF is overdone, the snow/rain ratio could get you 9-13" by Aberdeen. I hate worrying about the ice storm factor. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 I posted this in the UND-ATMOS storm disco page... " Models are notoriously bad at simulating leeside ejections, especially those without sufficient vertical resolution to properly resolve the Rocky mountain system and the effects it has on the synoptic evolution as the PV anomaly ejects. It is pretty common for these to ejects substantially farther south than modeled. I have little to zero confidence (in my humble opinion of course) the NAM has any shot of verifying. The SREFS also show this bias as they are limited in the vertical resolution department as well. Farther S ejection will tend to halt northward advancement as well...with substantial northern stream interference becoming a problem as the low begins its baroclinic development. ECMWF/RGEM/GFS are much better in the vertical resolution department." Personally I think this will end well S of what the NAM is depicting, but it will be fun to watch. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 I remember that storm...got 6" from it and was the biggest storm of the 2011-2012 season for my area. I remember that storm vividly...it was the top storm of the year while I was in North Platte during last winters debacle. I wrote a paper on it mostly discussing PV effects and latent heat release. Different setup completely, but the southern ejection applies here, and the ECMWF, IMHO, depicts what typically happens to an ejecting low in the low levels owing to PV stretching across the Rockies. Link to comment Share on other sites More sharing options...
ZackH Posted February 8, 2013 Share Posted February 8, 2013 I do think its clear that the NAM is an outlier at this point... but I still want to dream that it verifies... over an inch of QPF for the Forks... but I understand its not likely. But I'd say it IS possible. The trough isn't even over land yet... we should know more when it gets sampled better with the upper air data. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 8, 2013 Author Share Posted February 8, 2013 0z GFS ensembles at 72 Link to comment Share on other sites More sharing options...
Minnesota Meso Posted February 8, 2013 Share Posted February 8, 2013 It seems to me that the models are showing a less phased system over the NE CONUS, phasing just a bit ne of previous runs, how will that impact the track of our snowstorm??? Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 I do think its clear that the NAM is an outlier at this point... but I still want to dream that it verifies... over an inch of QPF for the Forks... but I understand its not likely. But I'd say it IS possible. The trough isn't even over land yet... we should know more when it gets sampled better with the upper air data. I still give it basically no shot at verifying. just seen this too much, and the NAM, oddly enough, it the most limited model when it comes to vertical resolution...which is so important for leeside ejections. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 It seems to me that the models are showing a less phased system over the NE CONUS, phasing just a bit ne of previous runs, how will that impact the track of our snowstorm??? I am liking MN more and more. Waiting for ECMWF before I call western and central MN into the game. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 0Z ECMWF track. Identical to 12z but deeper. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 8, 2013 Author Share Posted February 8, 2013 0Z ECMWF track. Identical to 12z but deeper. euro does nail nc NE, e SD, se ND & w half of MN with the heaviest qpf....maybe a ECM/GFS compromise as the GFS has been steady too. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 8, 2013 Share Posted February 8, 2013 euro does nail nc NE, e SD, se ND & w half of MN with the heaviest qpf....maybe a ECM/GFS compromise as the GFS has been steady too. I think the GFS is too far N too, but it is a viable solution. Canadian still looks odd with the very southern track, but will need to watch northern stream...as that can put a huge kabash on northward advancement real quickly with poorly resolved shortwaves. Link to comment Share on other sites More sharing options...
mnweather Posted February 8, 2013 Share Posted February 8, 2013 Euro has been trending slightly wetter with every run in MN. Link to comment Share on other sites More sharing options...
prinsburg_wx Posted February 8, 2013 Author Share Posted February 8, 2013 Euro has been trending slightly wetter with every run in MN. I think the euro has a bias with low qpf at times...something to do with mesoscale features. I read that off a FSD afd once. Link to comment Share on other sites More sharing options...
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