A-L-E-K Posted December 18, 2013 Share Posted December 18, 2013 500mb at 12z Sat. 18z NAM 12z GFS 12z Euro The GFS and NAM 850 picture by 6utc Sat is night and day. Not even talking about 84 hours here. Link to comment Share on other sites More sharing options...
Stebo Posted December 18, 2013 Share Posted December 18, 2013 500mb at 12z Sat. 18z NAM 12z GFS 12z Euro Nam is slower, also comparing the 12z GFS vs 06z GFS the 12z run is quicker with the southern stream vort on its run. Usually huge closed lows/strong troughs slow with time, something that would have huge ramifications in the long run as well Link to comment Share on other sites More sharing options...
hm8 Posted December 18, 2013 Share Posted December 18, 2013 End of run: west of the GFS... Link to comment Share on other sites More sharing options...
Ajdos Posted December 18, 2013 Share Posted December 18, 2013 Hoping for the best, but seriously it's so rare to see such a dynamic system. Where is the arctic air when we need it?... Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 18, 2013 Share Posted December 18, 2013 End of run: Cutting to MKE Link to comment Share on other sites More sharing options...
dmc76 Posted December 18, 2013 Share Posted December 18, 2013 GRR all in on the 12z runs... Link to comment Share on other sites More sharing options...
Stebo Posted December 18, 2013 Share Posted December 18, 2013 The GFS and NAM 850 picture by 6utc Sat is night and day. Not even talking about 84 hours here. Northern stream is quicker and flatter on the NAM you can see it is substantially colder just north of Lake Superior on this run compared to the GFS. Link to comment Share on other sites More sharing options...
toronto blizzard Posted December 18, 2013 Share Posted December 18, 2013 Cutting to MKE yup it will certainly do that. Link to comment Share on other sites More sharing options...
Hoosier Posted December 18, 2013 Share Posted December 18, 2013 Mentioned it previously but at least be aware of the potential for more model funny business after this wave moves into Mexico as Mexican data can be sparse. Link to comment Share on other sites More sharing options...
A-L-E-K Posted December 18, 2013 Share Posted December 18, 2013 Northern stream is quicker and flatter on the NAM you can see it is substantially colder just north of Lake Superior on this run compared to the GFS. I don't think it will matter much, it's just too weak of a player to counteract the southern stream. strong neg tilt trough with wide open gulf = hard left. unless the southwest 850 trends hundreds of miles south, we're done and it won't matter what the northern stream does. Link to comment Share on other sites More sharing options...
Justin Posted December 18, 2013 Share Posted December 18, 2013 So while everyone decided to lose their minds over this model run, I actually decided to look and see why everything shifted West so substantially. It has everything to do with the northern stream piece of energy that for whatever reason has now slowed down several hundred miles this run, could that happen sure, but I wouldn't buy into the northern stream slowing down at this junction. We had that happen last storm around this time frame and it ended up being completely wrong because subsequent runs ended up quicker with the northern stream. Furthermore the bigger problem will be that this northern stream piece of energy won't get sampled fully until 48 to 60 hours from now. So expect more swings in the models. Could it even go further West sure, but knowing how the northern stream works in these situations I would expect this to correct right some. I fully agree with this post... I think the latest runs, looking at everything in play, was an over-correction. Its going to be absolutely crucial where the phase takes place, how fast the system deepens, and moisture transport will certainly not be an issue. I would certainly wipe the 18+ inch amounts out at this point though due to temp profiles in the atmosphere and surface temps. Whoever wins probably gets a solid 9-14" and that could even be a bit aggressive. I still like the KC-QC-Beloit-Racine axis for the best snow totals....though that axis may have to be bumped slightly left... Link to comment Share on other sites More sharing options...
Stebo Posted December 18, 2013 Share Posted December 18, 2013 I don't think it will matter much, it's just too weak of a player to counteract the southern stream. strong neg tilt trough with wide open gulf = hard left. unless the southwest 850 trends hundreds of miles south, we're done and it won't matter what the northern stream does. Southern stream isnt going to crash through the northern stream so even if it is weak it still matters. Link to comment Share on other sites More sharing options...
Hoosier Posted December 18, 2013 Share Posted December 18, 2013 wow Link to comment Share on other sites More sharing options...
cyclone77 Posted December 18, 2013 Share Posted December 18, 2013 994 over Jomo at 84 on 18z NAM FWIW. It's cool we have another model to start looking at now that we're drawing closer. Link to comment Share on other sites More sharing options...
Hoosier Posted December 18, 2013 Share Posted December 18, 2013 Mentioned it previously but at least be aware of the potential for more model funny business after this wave moves into Mexico as Mexican data can be sparse. Here's a map that shows it. The US network is dense in comparison. Link to comment Share on other sites More sharing options...
harrisale Posted December 18, 2013 Share Posted December 18, 2013 Holy ZR. Another model run showing ridiculous amounts of ice. Over 1" of ice would be catastrophic for the GTA Transit would be completely out of service. Millions likely would be without power. Roads would be inaccessible. That would be bad. Very bad. You guys are certainly making this sound apocalyptic. Based purely on the latest EURO output, 2m temps seem way too marginal (-0.2C) to allow for such a copius amount of precip (0.86") to freeze on surfaces properly. Then we steadily warm up to a whopping +7.3C in the next 12 hours. There would definitely be some accretion but I think it would have a hard time really building up beyond the 12Z mark Sunday. We saw this in the April icestorm in Guelph where ice accretion at -1C could not keep up with the rainfall rate and a lot of the damage was mitigated. Of course there would still be numerous issues given the busy time of year but I doubt we would see the entire 0.86" + 0.11" of water turn to ice. Also this is base purely on this run of the EURO, any subsequent colder runs could spell trouble and the other models will need to be taken into account as well (ex. the GEM has been quite steady on a heavy ice event). Link to comment Share on other sites More sharing options...
hm8 Posted December 18, 2013 Share Posted December 18, 2013 MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 143 PM EST WED DEC 18 2013 VALID DEC 18/1200 UTC THRU DEC 22/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION WITH FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. CLOSED UPPER LEVEL LOW TO TRACK ACROSS NORTHERN MEXICO PLACEMENT OF THE FRONTAL BOUNDARY IN THE SRN PLAINS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z ECMWF / 12Z CMC CONFIDENCE: A LITTLE BELOW AVERAGE A CLOSED LOW IS EXPECTED TO DEVELOP ON THU OVER CALIFORNIA AND SLOWLY SWING SEWD ACROSS NRN MEXICO BEFORE POTENTIALLY EJECTING INTO THE SRN PLAINS ON SAT. THERE HAS BEEN SOME CONVERGENCE SEEN IN MODEL TRENDS...WITH SLOWER SOLUTIONS TRENDING FASTER AND FASTER SOLUTIONS TRENDING SLOWER. THERE IS STILL A SIGNIFICANT SPREAD SEEN IN THE LATEST ENSEMBLE SPAGHETTI HEIGHTS WHICH REDUCES CONFIDENCE SLIGHTLY BELOW AVERAGE. THE 12Z ECMWF TRENDED A LITTLE DEEPER AND NORTH WITH SHORTWAVE REACHING WEST TEXAS BY SAT EVENING...WITH THE 12Z CMC NEXT CLOSEST TO THE ECMWF. BY SAT...THE 12Z NAM IS SLOWEST...FOLLOWED BY THE 12Z ECMWF/CMC AND THE 12Z GFS/UKMET ARE TOWARD THE QUICKER END OF THE DETERMINISTIC SPREAD WITH THE ENSEMBLE MEANS SLOWER...BETWEEN THE NAM AND ECMWF/CMC. WILL RELY ON THE 12Z ECMWF/CMC FOR A COMPROMISE SOLUTION WITH THE NOTION THAT THE EC MEAN HAS BEEN TRENDING SLOWLY FASTER WITH EACH RUN BY SAT OVER THE SRN PLAINS. FRONTAL BOUNDARY EXTENDING FROM THE PLAINS TO THE NORTHEAST THU/FRI/SAT AND ASSOCIATED WAVES OF LOW PRESSURE Link to comment Share on other sites More sharing options...
gosaints Posted December 18, 2013 Share Posted December 18, 2013 DVN throws out the B word Link to comment Share on other sites More sharing options...
Geos Posted December 18, 2013 Share Posted December 18, 2013 I fully agree with this post... I think the latest runs, looking at everything in play, was an over-correction. Its going to be absolutely crucial where the phase takes place, how fast the system deepens, and moisture transport will certainly not be an issue. I would certainly wipe the 18+ inch amounts out at this point though due to temp profiles in the atmosphere and surface temps. Whoever wins probably gets a solid 9-14" and that could even be a bit aggressive. I still like the KC-QC-Beloit-Racine axis for the best snow totals....though that axis may have to be bumped slightly left... I could live with that! Racine always seems to do really well in these setups. Especially now since the lake waters are cooled off. Link to comment Share on other sites More sharing options...
buckeye Posted December 18, 2013 Share Posted December 18, 2013 if this is a legit trend, we're gonna have a nice weekend here in cmh Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted December 18, 2013 Share Posted December 18, 2013 You guys are certainly making this sound apocalyptic. Based purely on the latest EURO output, 2m temps seem way too marginal (-0.2C) to allow for such a copius amount of precip (0.86") to freeze on surfaces properly. Then we steadily warm up to a whopping +7.3C in the next 12 hours. There would definitely be some accretion but I think it would have a hard time really building up beyond the 12Z mark Sunday. We saw this in the April icestorm in Guelph where ice accretion at -1C could not keep up with the rainfall rate and a lot of the damage was mitigated. Of course there would still be numerous issues given the busy time of year but I doubt we would see the entire 0.86" + 0.11" of water turn to ice. Also this is base purely on this run of the EURO, any subsequent colder runs could spell trouble and the other models will need to be taken into account as well. Good post. Personally I think it will be mainly rain. Just a gut feeling. Temperatures are just way too marginal. Needless to say, Brett Anderson of accuweather has jumped on that bandwagon, but he's a warminista par excellence and sees warmth everywhere, just as JB sees cold. Link to comment Share on other sites More sharing options...
Hoosier Posted December 18, 2013 Share Posted December 18, 2013 DVN throws out the B word kinda misleading THE WINDS ALOFT AND SURFACE PRESSURES FORECAST DO NOT APPEAR TO MEET CRITERIA FOR AN EXPECTED BLIZZARD VIA PATTERN RECOGNITION FROM LOCAL STUDIES. THAT SAID...AGAIN...THIS STORM DOES APPEAR TO FIT INTO THE CATEGORY OF A HIGHER END WINTER STORM WITH BOTH HEAVY SNOW AND NOTABLE WIND EXPECTED FROM SATURDAY NIGHT THROUGH SUNDAY AFTERNOON. Link to comment Share on other sites More sharing options...
TimChgo9 Posted December 18, 2013 Share Posted December 18, 2013 did you have a valium for lunch? Yes, it was tasty. Link to comment Share on other sites More sharing options...
toronto blizzard Posted December 18, 2013 Share Posted December 18, 2013 Good post. Personally I think it will be mainly rain. Just a gut feeling. Temperatures are just way too marginal. Needless to say, Brett Anderson of accuweather has jumped on that bandwagon, but he's a warminista par excellence and sees warmth everywhere, just as JB sees cold. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted December 18, 2013 Share Posted December 18, 2013 I know. I just prefer to be pleasantly surprised. Link to comment Share on other sites More sharing options...
WestCoaster Posted December 18, 2013 Share Posted December 18, 2013 Given how rare a large ZR event is, the consistency in general from run to run for significant ice has been enough to make me nervous. I don't think this thing can go anymore north, and we're still in the thick of hours of freezing rain. Given the extensive snow cover I see no issues with this rain freezing on contact. I sure do hope you are right because the prospects of this much ZR in a city as large as Toronto is frightening. Link to comment Share on other sites More sharing options...
hm8 Posted December 18, 2013 Share Posted December 18, 2013 DTX DEEP UPPER TROUGH WILL BE LOCATED OVER THE DESERT SOUTHWEST AT 12Z SATURDAY. THE ASSOCIATED VORT MAX WILL LIFT LIFT NORTHEASTWARD TOWARD THE MO/IL VICINITY BY 12Z SUNDAY. MEANWHILE, A NORTHERN STREAM WAVE WILL BE MOVING FROM WEST-CENTRAL CANADA INTO THE NORTHERN PLAINS OVER THE SAME TIME FRAME. THESE TWO WAVES WILL BE THE MAJOR PLAYERS IN THE DEVELOPMENT AND MOVEMENT OF A SURFACE CYCLONE WHICH IS EXPECTED TO MOVE ALONG A TIGHT LOW-LEVEL BAROCLINIC ZONE FROM TEXAS INTO THE GREAT LAKES REGION. LOW-LEVEL WIND TRAJECTORIES EXTENDING FROM THE GULF OF MEXICO TO THE BAROCLINIC ZONE OVER THE UPPER MIDWEST SHOULD SUPPLY PLENTY OF MOISTURE TO THIS SYSTEM, SO CONFIDENCE IS HIGH ON A WET AND STORMY WEEKEND. CONFIDENCE IS STILL LOW, HOWEVER, ON P-TYPE. THIS IS DUE TO THE TIGHT BAROCLINIC ZONE AND MODEL DISAGREEMENT ON THE PATH OF THE SURFACE CYCLONE. FOR INSTANCE, THE 12Z RUNS OF THE GFS/ECMWF DEPICT THE LOW MOVING FROM ROUGHLY THE SOUTHERN TIP OF LAKE MICHIGAN TO SAGINAW BAY. THIS IS IN CONTRAST OF THE LAST SEVERAL RUNS, WHICH WERE RELATIVELY CONSISTENT IN A LOW TRACK TO OUR SOUTHEAST. ADDITIONALLY, GEFS MEMBERS DIFFER WITH RESPECT TO BOTH TIMING AND LOW TRACK. ACCORDINGLY, IT'S IMPORTANT NOT TO GET TOO HUNG UP ON VARIATIONS IN INDIVIDUAL MODEL RUNS UNTIL WE SEE BETTER MODEL AGREEMENT. SNOW, RAIN, AND FREEZING RAIN STILL ALL REMAIN A POSSIBILITY. PRECIPITATION MAY BEGIN OVER OUR SOUTHERN COUNTIES AS EARLY AS SATURDAY AFTERNOON AS MOISTURE TRANSPORT RAMPS UP. THE HIGHEST POPS OVER OUR CWA WILL BE ON SATURDAY NIGHT AND SUNDAY. WE DID ADD A MENTION OF FREEZING RAIN TO THE GRIDS ON SATURDAY NIGHT AND SUNDAY SINCE AN ANTICYCLONE PROGGED TO BE OVER CENTRAL CANADA LOOKS FAVORABLE TO PROVIDE A LOW-LEVEL FEED OF COLD AIR AS A WARM NOSE IS ESTABLISHED IN THE H7-H9 LAYER. THE LOW PULLS AWAY SUNDAY NIGHT AS ARCTIC AIR FILLS BACK INTO THE REGION. THIS MAY ALLOW SOME LAKE-EFFECT SNOW SHOWERS TO LINGER INTO SUNDAY NIGHT AND EARLY MONDAY. Link to comment Share on other sites More sharing options...
Hoosier Posted December 18, 2013 Share Posted December 18, 2013 LOT buying into the warmer/northwest solution at this time. Link to comment Share on other sites More sharing options...
Snowstorms Posted December 18, 2013 Share Posted December 18, 2013 You guys are certainly making this sound apocalyptic. Based purely on the latest EURO output, 2m temps seem way too marginal (-0.2C) to allow for such a copius amount of precip (0.86") to freeze on surfaces properly. Then we steadily warm up to a whopping +7.3C in the next 12 hours. There would definitely be some accretion but I think it would have a hard time really building up beyond the 12Z mark Sunday. We saw this in the April icestorm in Guelph where ice accretion at -1C could not keep up with the rainfall rate and a lot of the damage was mitigated. Of course there would still be numerous issues given the busy time of year but I doubt we would see the entire 0.86" + 0.11" of water turn to ice. Also this is base purely on this run of the EURO, any subsequent colder runs could spell trouble and the other models will need to be taken into account as well (ex. the GEM has been quite steady on a heavy ice event). If this is solely an Ice storm i personally believe it will be hard for the Ice to accumulate near the Lake Shoreline because the Lake would regulate temperatures just enough for it be less severe than those away from the Lake. The GGEM has been consistent on its "Ice storm" idea for the GTA as compared to the other models. This storm is still days out so at this point in time any solution is viably possible. Models can be too quick in moving systems before they phase or interact. I wouldn't expect any type of consistency on the models till 0z/12z Friday. I think we need to focus on the quick hitting snowfall/mixing on Friday for the GTA too. Link to comment Share on other sites More sharing options...
TimChgo9 Posted December 18, 2013 Share Posted December 18, 2013 Well, all of this talk of ice storms got me thinking about one, probably March of 1982, I think. Ice was everywhere, power was out all over, and yet, our high school refused to close, so it was off to school we went. I remember my dad taking my brothers and I to school, because there was no way we could walk, and struggling to stay on the slippery road. It was just about 1.5 miles to school, and it took us 20 minutes to get there. I remember practically skating along the parking lot to the main entrance. Only about 1/4th of the students made it to school, classes of mine that normally had 30 students had less than 10. I don't remember how much ice we got, but it remained for a few days after. I remember the trees in our back yard shedding some branches, and many trees at our local park also lost some limbs. It was either March of '82, or March of '83, Link to comment Share on other sites More sharing options...
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