0z Models 12/22/10

[HM]

I know we have the strong westerlies from the fast Pacific flow La Nina pattern, but I would think the strong westerlies would actually help the northern stream act in our favor. Considering there is blocking to the east and north, westerlies and north westerlies from a La Nina would actually help to push the northern stream south and south east. As Will alluded to before, perhaps without the strong westerlies, you get the phase job too far west, and the low could ride up the Hudson Valley, since the westerlies help to have some sort of eastward component to the northern stream's dive. Obviously, you don't want too much of that, but I'm pretty sure that without the strong westerlies, this would cut up the Hudson Valley.

The westerlies are going up and over a giant western ridge which if anything has slowed down its eastward progression from the 12z run to the 00z run of the euro. But, I do agree that the eastward West Ridge is helping and there is a delicate balance between where this positions and how fast the 50-50 low moves out in determining where the phasing goes down.

[earthlight]

Animate the 200mb jet on the latest 06z NAM and you can see the ridge axis amplifying majorly after 60 hours, trying it's hardest to amplify the pattern downstream.

[earthlight]

300mb jet way more amplified this run compared to 00z..110kt jet streak assoc. with the northern stream feature is diving southeast.

[psuhoffman]

phasing is starting at 78 hours but its out of sync. Northern energy is hanging back a bit and not coordinated with the STJ that is getting out ahead again. We need this phase to happen smooth and for this to bomb fast.... NAM is better but might be wide right

[psuhoffman]

another observation, the euro seems to have the southern stream more dominant during the phasing process...really digs the storm south and then starts to bomb it as it moves out of the gulf. The other guidance is close up to that point...but they are northern stream dominant during the process and I think that is the problem. The northern energy is still diving SE behind the huge vortex to its east, but the other models have the northern stream dominate and pull everything east before finally phasing enough to turn north...but too late. The euro keys on the STJ and thus everything digs more and wraps up. Not sure how we can tell which scenario is more likely at this time.

[earthlight]

It's definitely much better at 84 hrs...I would have to assume it would look something like the GGEM if somebody held a gun to my head. The jet streak is impressive and the trough is amplifying rapidly...I would say this would probably get tucked up the coast but not quite enough. Comparing the H3 jet to the 00z GFS shows a much more consolidated and amplified solution on the NAM which would argue for a more amplified track. Also check the northern stream jet streaks which aid significantly in our trough amplification...GFS has it north of the international border while the NAM already has it in the Central Plains.

06z NAM

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/06/images/nam_300_084s.gif

00z GFS

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_300_090s.gif

[tombo82685]

the 0z euro and 84 hr nam are still very close to each other

[psuhoffman]

its improved but the trough is still too pos tilted at 84 hours...it needs to be going neutral at that point. This run would probably work out good for New England if I had to guess.

[psuhoffman]

The southern stream energy is definitely the difference between the euro and all other models right now, and why the euro is going nuts with the storm. That is the key... the euro and NAM are identical in every way except that. The euro still has a very strong vort down in the Gulf at 90 hrs. The 84 hour NAM is losing that feature in favor of the northern stream energy. It seems if the northern stream dominates, this slides too far east because its not digging as much and takes too wide of a turn. If the energy in the gulf is stronger and the phasing happens down there, everything digs in deeper and its a sharper turn up the coast. Anyone else notice this?

[SnowGoose69]

I'm currently sticking with a miss for everyone outside of SE VA/NE NC, E LI, RI, and E MA...I'm going on the assumption that the Euro/NAM are too slow evolving things out of the SW and Plains and the GFS is too fast...that leaves us somewhere between which is a near miss for most now...plenty of time to change but everyone is only being warned of the POSSIBILITY of a storm now and not likelihood outside of those places.

[BethesdaWX]

I'm wondering, people are saying that the 50/50 low in the atlantic is preventing this from becoming an apps runner/interior event or something......so, if the 50/50 low were to weaken somewhat or displace from current guidance, would that allow for a track closer to the coast, perhaps divergent in what we've seen progged? I understand the specifics cannot be nailed down at this point, but how would the placement/strength of that thing affect our "storm"?

[Voyager]

looping this thing is awesome heads up along the coast stops and makes a 90 degree turn pretty wild looking

Not that it's the final outcome, but I'd like to NOT see this. Seems like there's always something....

[jconsor]

Looks like HPC is going with the ECMWF for the most part. Very insightful discussion.

...EUROPEAN CENTRE GUIDANCE STAYS THE COURSE ON POWERFUL EAST

COAST STORM DECEMBER 26-27...

WILL STICK WITH THE CONSISTENT ECMWF FOR THE PRELIMINARY FRONTS

AND PRESSURES FOR DAYS 3-7. FOR THREE CONSECUTIVE MODEL

CYCLES...THE DETERMINISTIC ECMWF HAS INDICATED A

MASSIVE...DEEP...SLOW-MOVING CYCLONE HUGGING THE CAROLINA AND MID

ATLANTIC COASTS THE TWO DAYS FOLLOWING CHRISTMAS. THE ECMWF AND

UKMET WERE THE FIRST OF THE GLOBAL NUMERICAL MODELS TO SWITCH FROM

TRACKING THIS WAVE ALONG 40N THROUGH THE MIDWEST...TO A SUPPRESSED

PATH ACROSS THE DEEP SOUTH. SINCE THIS BREAK-AWAY...THE UKMET

SPLIT OFF EVEN FARTHER SOUTH...WITH THE ECMWF LOCKING ONTO AN

EVOLUTION THAT TAKES THE DEVELOPING LOW TO THE FLORIDA PANHANDLE

AND THEN SHARPLY UP THE EASTERN SEABOARD. THE GEM GLOBAL FOLLOWED

THE EUROPEAN CENTRE TRACK ON ITS 00Z/21 RUN...BUT HAS SWUNG THE

SYSTEM OUT WIDER OVER THE ATLANTIC THE LAST TWO RUNS. THE GFS HAS

SHIFTED TO THE SOUTHERN ROUTE ACROSS THE GULF STATES ON ITS

CURRENT RUN...BUT LIKE THE GEM GLOBAL...DIRECTS THE CYCLONE WELL

SOUTH AND EAST OF CAPE HATTERAS.

THE ECENS MEMBERS HAVE AVERAGED CLOSE TO THE DETERMINISTIC ECMWF...

WITH MANY MEMBERS FOLLOWING IT EXACTLY...AND OTHERS TRACKING A BIT FARTHER

OFFSHORE. THE EUROPEAN CENTRE GUIDANCE HAS THE ADVANTAGE IN DEVELOPMENTAL

SYSTEMS WITH ITS HIGH RESOLUTION...AND IS FURTHER AIDED BY ITS

4D-VAR ANALYSIS IN GENERAL. ITS ENSEMBLE MEMBERS ARE MORE HIGHLY

RESOLVED THAN THE GEFS MEMBERS...AND WITH DYNAMIC...DEVELOPMENTAL

SYSTEMS...THE EUROPEAN GUIDANCE SHOULD HAVE THE EDGE.

INDEED...THE GEFS MEAN HAS BEEN CONSISTENTLY FLATTER WITH THE PATH

OF THE BIG STORM...WHICH IS CERTAINLY IN LINE WITH THE LOWER

RESOLUTION. EVEN SO...FOUR 00Z/22 GEFS MEMBERS STILL TRACKED

COMPARABLY TO THE ECMWF...SHOWING A DEEP NOREASTER AND A HIGH

IMPACT STORM FOR THE MAJOR METROPOLITAN AREAS ASTRIDE INTERSTATE

95 FROM WASHINGTON TO BOSTON. TO WIT...THESE GEFS MEMBERS ARE

GOING AGAINST THEIR LOWER RESOLUTION/LESS DEVELOPMENTAL NATURE.

THE ECMWF HAS MUCH CLIMATOLOGY ON ITS SIDE AS WELL...WITH ITS

TRACK WEST OF THE GULF STREAM...AND THE BOMBING PHASE NEAR AND

NORTH OF CAPE HATTERAS.

THE MOST UNUSUAL...AND THREATENING...ASPECT OF THE ECMWF FORECAST

IS THE RELATIVELY LOW LATITUDE AT WHICH THE STORM MATURES AND

STALLS/LOOPS. MORE TYPICALLY...SYSTEMS WILL CLOSE OFF AND HOVER

OVER THE WATERS SOUTH OF NOVA SCOTIA...AS WITH THE MOST RECENT

CYCLONE STILL AFFECTING DOWNEAST MAINE. THE ECMWF SHOWS THE

UPCOMING CIRCULATION COMING TO A HALT JUST EAST OF THE DELMARVA

PENINSULA...WHICH PUTS THE VERY POPULATED AREAS OF THE EASTERN MID

ATLANTIC...LONG ISLAND...AND SOUTHERN NEW ENGLAND IN A PROLONGED

PERIOD OF HIGH WINDS AND HEAVY PRECIPITATION...MOSTLY SNOW. THE

EXTRAORDINARY NEGATIVE NAO THIS MONTH COULD CERTAINLY SUPPORT SUCH

AN ANOMALY. EVEN BEFORE THE RAPID DEEPENING PHASE OF THE

SYSTEM...AREAS OF THE DEEP SOUTH FROM THE INTERIOR GULF COAST

STATES TO GEORGIA AND THE MOUNTAINS AND PIEDMONT OF THE CAROLINAS

MAY SEE A VERY RARE WHITE CHRISTMAS...AGAIN...CONSISTENT WITH THE

REMARKABLE DISRUPTION AT HIGH LATITUDES.

CISCO

[isnice]

I gotta admit, the 00z ECMWF is shocking, but the ensembles are further east

[Snow_Miser]

I gotta admit, the 00z ECMWF is shocking, but the ensembles are further east

GGEM ensembles are west.

[am19psu]

GGEM ensembles are west.

Not the map I'm looking at. The sfc low crosses 70W at 35N and crosses 40N at 62W.

[afvet89]

JM! Just found the board, used to post with ya in the Central PA threads at EUSWX. VERY interesting storm, but like you said, we'll follow tradition and watch from the bench in CPA lol.

Hey buddy, good to see you back again!

[SP]

Adding some fuel to the fire- the 00Z Euro ensembles are MUCH less impressed- kind of a moderate mainly coastal event-the Op is a big outlier. Sorry, this increases my unease that we are all (including myself for a while) getting way too worked up about what may end up being a nice event for some, and a complete bust for others.

this

BTW besides making a fine observation you also described the vast majority of the activity here during the winter. FYI one of the new features of AmWx is each membership comes with a supply of paxil to help take the edge off

Next thing you know those coastal areas which get hit have temp issues

[thegreatdr]

If you look over any individual's forecast over a series of weeks, months, or years, you will notice a bias, whether it is in regards to the choice is of a particular model or pair of models or towards certain solutions for their backyard, whether extreme in impact or not. The bias could be always going for consensus. We all have them. Just search older discussions if you want to know if an individual forecast has any sort of bias. The key to recognizing biases is to see if any individual forecaster is just emphasizing positives (in this case the most menacing possible solution), or is actually weighing both the positives and the negatives for either a certain meteorological event, or per your first question, a certain piece of model guidance. Just keep in mind that for the 09z medium range issuance, the individual 00z EC and 00z Canadian ensemble members and the 00z ECMWF ensemble mean are not available to HPC. Those show up between 5 and 6 am EST, or 10-11z. As it stands, this board seems to have access to the 00z guidance via the web about 10 minutes faster than HPC.

DR

Does CISCO have an ECM bias?

Let me reword that ..is what he says not true?

[Gibbsfreeenergy]

If you look over any individual's forecast over a series of weeks, months, or years, you will notice a bias, whether it is in regards to the choice is of a particular model or pair of models or towards certain solutions for their backyard, whether extreme in impact or not. The bias could be always going for consensus. We all have them. Just search older discussions if you want to know if an individual forecast has any sort of bias. The key to recognizing biases is to see if any individual forecaster is just emphasizing positives (in this case the most menacing possible solution), or is actually weighing both the positives and the negatives for either a certain meteorological event, or per your first question, a certain piece of model guidance. Just keep in mind that for the 09z medium range issuance, the individual 00z EC and 00z Canadian ensemble members and the 00z ECMWF ensemble mean are not available to HPC. Those show up between 5 and 6 am EST, or 10-11z. As it stands, this board seems to have access to the 00z guidance via the web about 10 minutes faster than HPC.

DR

There is something wrong with this. There are weather vendors out there that are not that expensive per month...hard to believe that individual hobbiests and consultant Mets can pay the fees per month to have access to the full ECMWF op and ens package and our government can't.

[thegreatdr]

We have agreements with the UKMET, Canadian, and ECMWF centers to get any or all of their data. WIth the ECMWF and the ECMWF ensemble means, we limit what we get since the volume of data from their guidance is enormous, due to its higher resolution and the multitude of ensemble members available. When we received all the ECMWF ensemble mean fields a couple years ago for a few days, the 00z run wasn't available until noon at HPC! The UKMET comes in methodically, like any NCEP guidance, but does lag what you all see by about 5 minutes. In the case of the ECWMF, the data for the operational output comes in clumps of about 36 hours at a time every 10 minutes, and in between clumps this board sees the guidance before we do. In the case of the Canadian, it all comes in at once, around 1807z on day shift but sometimes as late as 0050z on night shift, so in the case of the Canadian you see it all way before it shows up in our nAWIPS workstations. But, we can look up the Canadian online just like the rest of you do. But, we can't underlay it within nAWIPS unless it is in our workstations, and different meteorologists have different comfort levels with comparing guidance side to side, rather than right on top of one another.

DR

There is something wrong with this. There are weather vendors out there that are not that expensive per month...hard to believe that individual hobbiests and consultant Mets can pay the fees per month to have access to the full ECMWF op and ens package and our government can't.

[Ender]

There is something wrong with this. There are weather vendors out there that are not that expensive per month...hard to believe that individual hobbiests and consultant Mets can pay the fees per month to have access to the full ECMWF op and ens package and our government can't.

I believe all the vendors, and the gov, will receive the feed of data at the same pace. How fast they render their images will depend on the number and complexity of analysis/maps/subregions and the speed of the systems performing the rendering AND the priority assigned to those image renders. The private firms are in the business of providing the basic/general look and feel of the deterministic forecast absolutely as fast as possible. NCEP/NWS doesn't have the same priority, it's not "do or die" in 3min or less. Other work/images competing for CPU time and release deadlines.

As for the ensemble members, I think they do see the spagetti.