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March 25-26 storm potential


Mitchel Volk

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He spoke about the pattern and potential for a historic storm. He discussed things very well. I also think that there is a lot of potential.

 

My point concerns strictly putting out a map of forecast accumulations at this point in time. The science is not good enough to pinpoint accumulations at this timeframe. There's a lot of uncertainty. Historic data and seasonal climatology argue for caution.

 

The potential seems on the table. But that's the best that can be said right now and Dr. Ventrice discussed things very well.

 

Don,

I agree fully with your opinion about accumulation maps but I still disagree with your use of climateogy when thinking about the outcome of a current pattern.  If this were a year ago I would certainly argue that the chances of an accumulating snowfall next week are very slim based on climo because the progged set up would be very unlikely.  I know we will probably never agree on this.  I would love to have a thread devoted to this topic.  I tried last year but it didn't get much response (mostly you and Ray). 

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Don,

I agree fully with your opinion about accumulation maps but I still disagree with your use of climateogy when thinking about the outcome of a current pattern.  If this were a year ago I would certainly argue that the chances of an accumulating snowfall next week are very slim based on climo because the progged set up would be very unlikely.  I know we will probably never agree on this.  I would love to have a thread devoted to this topic.  I tried last year but it didn't get much response (mostly you and Ray). 

My use of historic climatology/seasonal climatology wasn't meant to infer that the pattern isn't favorable. I believe it is. I meant to argue that the science isn't good enough to make forecast maps right now. Portraying a climatological extreme in the face of high uncertainty only magnifies the risks of making such maps right now. The potential exists for a large storm. Pinpointing the details as the map tries to do simply isn't possible.

 

Also, I referenced two historical outcomes to show that a huge snowstorm is not a zero probability event at this late part of the season. But where such an impact occurs, if it does, remains very uncertain right now.

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I'm imagining you slowly falling asleep while typing this with your head now on the keyboard.

Ill admit john has me over here trying to decipher this in hopes of finding something relevant to this storm :lol:

Anyway, messiah of the NYC metro forum what are your thoughts thus far?

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WPC


 

WITH THE REESTABLISHMENT OF CROSS-POLAR FLOW INTO NORTH AMERICA DURING THE NEXT FEW DAYS, BAROCLINICITY WILL MARKEDLY INCREASE. THE LATE-MARCH SUN CONTINUES TO WARM AREAS SOUTH OF THE POLAR FRONT, WITH THE INFUSION OF NEARLY UNMODIFIED ARCTIC AIR INTO THE NORTHERN TIER OF STATES. THIS THERMAL CONTRAST IS, OF COURSE, PART AND PARCEL OF THE JET STREAM, WHICH IN TURN PROVIDES THE BACKGROUND ENERGY FOR THE PERTURBATIONS WENDING THROUGH THE FLOW. SOME OF THE DEEPEST EXTRATROPICAL CYCLONES IN MODERN RECORD-KEEPING HAVE AFFECTED THE CONTIGUOUS UNITED STATES DURING THE MONTH OF MARCH--THEIR GENESIS AFFORDED BY THE MONTH'S NATURAL BAROCLINIC INSTABILITY.

ONCE SUCH PERTURBATION IS PROGGED TO GROW VIGOROUSLY AS IT LIFTS UP THE SOUTHEAST COAST TUESDAY MORNING, THEN BOMB OFF THE MID-ATLANTIC COAST TUESDAY NIGHT WHEN THE JET STRENGTHENS VIA AN INJECTION OF ARCTIC AIR FROM THE MIDWEST. MANY MODELS--INCLUDING THE 00Z/21 GFS--DEEPEN THE OCEAN STORM BELOW 970MB NEAR THE ATLANTIC BENCHMARK OF 40N/70W WEDNESDAY MORNING. FOR THIS PARTICULAR SET OF MANUAL PROGS, RELIED ON THE MOST RECENT ECENS MEAN FOR A BEARING, SINCE NOT ALL THE GUIDANCE WAS YET ON THE SAME PAGE WITH THE PARTICULARS OF THE CYCLONE. THE ECENS MEAN HAS SHOWN HIGH SKILL AT THE MEDIUM RANGE WITH SURFACE PRESSURES, AND SEEMS TO OFTEN ARRIVE AT A STABLE SOLUTION A DAY OR SO SOONER THAN MUCH OF THE OTHER GLOBAL NUMERICAL GUIDANCE.
THE EAST-COAST CYCLONE HAS THE POTENTIAL TO PRODUCE LATE-SEASON HEAVY SNOWFALL OVER A WIDE SWATH OF REAL ESTATE FROM VIRGINIA TO NEW ENGLAND; THAT IS A GENERALITY AT THIS POINT. MUCH REMAINS IN TERMS OF REFINING THE FORECAST STATE BY STATE. ANOTHER HIGH-IMPACT FACTOR WILL BE THE POWERFUL WINDS GENERATED BY THIS SPRAWLING, INTENSE CIRCULATION, ALONG WITH HIGH SEAS, BEACH BATTERY, COASTAL FLOODING, AND SO FORTH. AGAIN, AT THIS POINT, SUCH SENSIBLE WEATHER EFFECTS ARE SIMPLY ATTENDANT TO THE POTENTIAL OF SUCH A STORM.
[/indent]
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One thing to keep in mind is that the main reason we don't see huge snowstorms in March and especially late March is because we usually end up in the warm side of the storm and get rain or a mix of slop while the interior gets hit. The issue lately and MAYBE this time around is the OPPOSITE. We're dealing with an anomalous pattern that might suppress the storm to our south. So, odds favor this storm coming NW, maybe even significantly. However, with how things have gone lately, it could trend even further south

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BTW, the 00z Canadian is probably the most ridiculous solution I've ever seen in my life. Looking at H5 the cause for the further eastern low is a vort max that doesn't phase in but amplifies around the trough with the rest of the energy. I would love to see this play out just to see the craziness but it doesn't make any sense.

 

This doesn't appear to be a result of convective feedback, it has the same low pressure that the GFS and Euro both have, but the northern stream only partially phases and that's why we get a double barreled low. It would appear that this is going to come down to the strength of the waves.

 

Most of our bigger miller A's, boxing Day included, the northern stream was dominant, right now the models seem to waffling back and forth with the amount of phasing that occurs and which stream to focus on.

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The 0Z CMC seems to have an inverted trough at hour 126 directly over us while the other lobe is out well to the east. At 500mb Vort. there are two separate centers. GFS just one large area of vorticity. Comments?

Seems my question was answered above, right as I was asking it!

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what are your thoughts thus far?

 

My thoughts haven't changed since three days ago. I don't think we have reached a point with forecast models where confidence can be fully increased in any way yet. The important pieces of the pattern remain the same and these have been discussed. To me, the most critical is the upper level low in the Eastern Pac which develops over the next few days. This helps to amplify the ridge on the west coast which is very important for the pattern to the east of that and the amplification which occurs near the MS River. Last nights modeled trended slightly more progressive with this feature. 

 

The other is the trough/lower heights over Southeast Canada into the Northwest Atlantic. We don't have blocking int he high latitudes or any 50/50 low so we essentially need this to remain as modeled to help slow down a very fast mid level flow, albeit briefly. 

 

My gut tells me that the ridge axis on the west coast needs to stay amplified for longer than currently modeled if this storm is going to tuck in near the coast. And that is not a bet I would want to take right now given the very fast and progressive nature of the Pacific pattern. That being said, all models are in good agreement on a very, very energetic disturbance racing southeastward through the Central US and then phasing/amplifying in the Southeast US. There are very impressive jet streaks involved and tons of dynamics. So all bets are off until we start to get closer into a range where models can begin to discern between individual disturbances and interactions. 

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both years were neutral negative like this year...I'm not giving up on snow until the cold shots stop...

 

Getting this far enough west would be like an athlete that finally winning the one grand slam event that has been

eluding them for their career after winning the other three multiple times.

 

The snowfall events have been exceptional here during the 2000's with record

events in late October into early November along with truly memorable snows across the heart of the season.

The only thing we have been missing so far has been the great very late season event. So the stakes

are very high going forward since a very slight change in the UA pattern stands between something special

or a little further east solution.

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The 0Z CMC seems to have an inverted trough at hour 126 directly over us while the other lobe is out well to the east. At 500mb Vort. there are two separate centers. GFS just one large area of vorticity. Comments?

Seems my question was answered above, right as I was asking it!

 

Could be convective feedback as mentioned by others, the 12z EURO did this as well. If you look at 700mb jetstream even on the GFS you can actually see two different circular jets. 

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It is interesting that the really tucked in models are developing almost a separate low with the phasing energy closer to the coast. I know everyone seems to rather want a Miller A, but IMO this initial southern low is actually pushing the baroclinic zone farther East.

We've seen a lot of waffling back and forth with the amount of phasing that occurs. An all out phased bomb produces a solution similar to the 12z ECMWF, and if it can really amplify and turn the corner fast enough, it can get pulled back towards the coast.

 

I believe this is a case where we would benefit from one of two solutions...

 

1) The energy only partially phases, we end up with an inverted trough like feature along the coast.

 

2) The second piece of arctic energy phases in fast enough on the back side to flip the trough negative tilt and we get a fully phased rapidly deepening bomb.

 

If we get a delayed full phase, that's how you end up with a 00z Euro or GFS solution.

 

The PNA FWIW has been running more positively than forecasted, albeit still in negative territory and the amplification of the western ridge is purely related to the amplitude of the ULL south of Alaska.

 

Hopefully the models trend back towards more amplification with that feature and then we should be in business, my gut feeling tells me that this will come west today with the 12z guidance.

 

pna.sprd2.gif

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Could be convective feedback as mentioned by others, the 12z EURO did this as well. If you look at 700mb jetstream even on the GFS you can actually see two different circular jets. 

I'm not a met but it appears to be the result of a sloppy phase between two very potent and separate short waves rather than convective feedback.

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I'm not a met but it appears to be the result of a sloppy phase between two very potent and separate short waves rather than convective feedback.

In situations like this it seems very farfetched there would be two low centers like that-one tucked in and one well out to sea. There will likely be the one main low in either place. I don't think I've ever seen a situation like that.

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The 06z GEFS mean while it has some NW members definitely is leaning towards a further east track.

 

gefs-spag_namer_126_mslp_1000_1040_iso.g

 

Overall the cluster looks similar to 00z.

 

gefs-spag_namer_132_mslp_1000_1040_iso.g

I'd have to hedge for mostly out to sea for now given the progressiveness of the pattern overall. We will need a major amplification over western Canada in order for the downstream troughing to dig and for the phase to maybe happen early enough. If so we could see a major storm close enough, but if that ridge is flatter or more progressive, the trough will be pushed east or won't become amplified enough.

 

One thing's for sure-there's enough energy and baroclinicity around to make for a ferocious storm if it all does come together. This could be a beast somewhere.

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I'd have to hedge for mostly out to sea for now given the progressiveness of the pattern overall. We will need a major amplification over western Canada in order for the downstream troughing to dig and for the phase to maybe happen early enough. If so we could see a major storm close enough, but if that ridge is flatter or more progressive, the trough will be pushed east or won't become amplified enough.

 

One thing's for sure-there's enough energy and baroclinicity around to make for a ferocious storm if it all does come together. This could be a beast somewhere.

 

 

LI is in a good spot for this one.

There is no piece of guidance that does not give LI at least 3"+ of snow right now for the western sections and 6"+ for the Eastern sections.

 

IMO, this is a classic LI and SNE storm with a very tight cutoff west of EWR.

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The 0z Euro mean shifted east? I just read DT's latest post and he said that it barely budged.

you do not want a tucked in to the coast low on March 25th - be glad its not showing that YET but the March 28 -29 1984 analog low I posted last night is still a possibility that one was close to the coast and too strong and NYC did not get as much snow as it could have if the low was further east

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