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NYC/PHL Jan 25-28 Potential Threat Part 2


am19psu

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By the way, I don't want to come off as the storm hater on this. The threat, from the H5 depiction being shown, amount of QPF, and the potential pressure gradient involved with the departing high alone, makes this really interesting and potentially awesome. I'm excited for it, and I vision a good deal of snow in the coastal locations is still possible at the onset given the current models, before a change to rain. It was just baffling me when people were screaming this is a HECS setup for I95 corridor with our arctic high sailing away offshore as the storm comes up the coast. Y'all need to open up your KU books to find what 95% of I95 HECS are made of. I'm getting excited for our inland folks.

Agree. Volume1-Chapter 5. Describes the near miss events for the Northeast corridor. Will help you understand this upcoming storm much better.

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AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MOUNT HOLLY NJ

312 PM EST FRI JAN 21 2011

.....LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

-- Changed Discussion --ON MONDAY NIGHT, A CLOSED MID LEVEL LOW IS FORECAST TO BE OVER THE

LOWER MISSOURI RIVER VALLEY AND THE MIDDLE MISSISSIPPI RIVER VALLEY.

THE FEATURE IS EXPECTED TO PROGRESS TO THE EAST, REACHING THE MIDDLE

ATLANTIC COAST ON WEDNESDAY. THE LOW IS THEN FORECAST TO LIFT

NORTHEASTWARD TO NOVA SCOTIA AND VICINITY FOR LATE THURSDAY INTO

THURSDAY NIGHT. A MID LEVEL TROUGH FROM THE NORTHWEST IS EXPECTED TO

DROP OVER THE NORTHEASTERN STATES FOR FRIDAY.

AT THE SURFACE, COLD HIGH PRESSURE IS EXPECTED TO BE LOCATED OVER

SOUTHERN QUEBEC AND NORTHERN NEW ENGLAND ON MONDAY NIGHT. THE HIGH

SHOULD PROGRESS SLOWLY TO THE EAST. LOW PRESSURE IS FORECAST TO

DEVELOP OVER THE SOUTHEASTERN STATES OR OFF THE SOUTHEAST COAST ON

TUESDAY. THE LOW IS THEN EXPECTED TO WORK ITS WAY NORTHEASTWARD,

POSSIBLY BRINGING OUR REGION ANOTHER WINTER STORM FOR LATE TUESDAY

INTO WEDNESDAY. THE TRACK OF THE POTENTIAL SYSTEM REMAINS UNCERTAIN.

HOWEVER, PRESENT INDICATIONS SUGGEST MAINLY SNOW IN OUR REGION, WITH

MIXED PRECIPITATION ON THE COASTAL PLAIN.

AS THE STORM LIFTS TO OUR NORTHEAST ON THURSDAY AND FRIDAY, IT

SHOULD REMAIN COLD IN OUR REGION WITH PERHAPS A FEW LINGERING SNOW

SHOWERS, ESPECIALLY ON THURSDAY.

-- End Changed Discussion --

Mt Holly's ATTM looking at a snow event for I95 cooridor, FWIW.

Can't wait to get Glenn's take on this.

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Coastal is saying that euro ensemble has similar low track as operational but faster.

I would think that its better that its faster.

Waiting to see the mean precip maps from a friend who has access.

There's a lot of E-W spread in the H5 charts, but they're all really amplified. Whoever gets snow is going to get dumped on.

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Why are we assuming that the high WILL slide off the coast at the time that it is shown to do so? Isn't the high sliding off the coast a product of the forecast made by the model in the previous frames? Which means that can change quite a bit between now and 120 hours. Especially this year, everyone should realize how LOOOONG 120 hours really is when predicting a snowstorm. Not saying this can't be a driving rainstorm, but taking a high sliding off the coast at the exact time it is shown to do so as fact 5 days out doesn't make sense to me. Ace...

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Interesting. Here is the Weather Channel forecast for the Southern Poconos:

Jan 25 TuesdayA few snow showers. Highs in the low 20s and lows in the mid teens.Jan 26 WednesdayWindy with a wintry mix of precipitation. Highs in the upper 20s and lows in the upper teens.Jan 27 ThursdayA few snow showers possible, windy. Highs in the low 30s and lows in the mid teens.

What forecast model at this point is bring p-type issues this far west (Albrightsville, PA)? From what I can see any p-type issues would be on the coastal plain on eastward. Am I missing somehting?

D

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AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MOUNT HOLLY NJ

312 PM EST FRI JAN 21 2011

.....LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

-- Changed Discussion --ON MONDAY NIGHT, A CLOSED MID LEVEL LOW IS FORECAST TO BE OVER THE

LOWER MISSOURI RIVER VALLEY AND THE MIDDLE MISSISSIPPI RIVER VALLEY.

THE FEATURE IS EXPECTED TO PROGRESS TO THE EAST, REACHING THE MIDDLE

ATLANTIC COAST ON WEDNESDAY. THE LOW IS THEN FORECAST TO LIFT

NORTHEASTWARD TO NOVA SCOTIA AND VICINITY FOR LATE THURSDAY INTO

THURSDAY NIGHT. A MID LEVEL TROUGH FROM THE NORTHWEST IS EXPECTED TO

DROP OVER THE NORTHEASTERN STATES FOR FRIDAY.

AT THE SURFACE, COLD HIGH PRESSURE IS EXPECTED TO BE LOCATED OVER

SOUTHERN QUEBEC AND NORTHERN NEW ENGLAND ON MONDAY NIGHT. THE HIGH

SHOULD PROGRESS SLOWLY TO THE EAST. LOW PRESSURE IS FORECAST TO

DEVELOP OVER THE SOUTHEASTERN STATES OR OFF THE SOUTHEAST COAST ON

TUESDAY. THE LOW IS THEN EXPECTED TO WORK ITS WAY NORTHEASTWARD,

POSSIBLY BRINGING OUR REGION ANOTHER WINTER STORM FOR LATE TUESDAY

INTO WEDNESDAY. THE TRACK OF THE POTENTIAL SYSTEM REMAINS UNCERTAIN.

HOWEVER, PRESENT INDICATIONS SUGGEST MAINLY SNOW IN OUR REGION, WITH

MIXED PRECIPITATION ON THE COASTAL PLAIN.

AS THE STORM LIFTS TO OUR NORTHEAST ON THURSDAY AND FRIDAY, IT

SHOULD REMAIN COLD IN OUR REGION WITH PERHAPS A FEW LINGERING SNOW

SHOWERS, ESPECIALLY ON THURSDAY.

-- End Changed Discussion --

Mt Holly's ATTM looking at a snow event for I95 cooridor, FWIW.

Can't wait to get Glenn's take on this.

Great sign seeing Mt Holly stay on the wintry side for this storm.

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Why are we assuming that the high WILL slide off the coast at the time that it is shown to do so? Isn't the high sliding off the coast a product of the forecast made by the model in the previous frames? Which means that can change quite a bit between now and 120 hours. Especially this year, everyone should realize how LOOOONG 120 hours really is when predicting a snowstorm. Not saying this can't be a driving rainstorm, but taking a high sliding off the coast at the exact time it is shown to do so as fact 5 days out doesn't make sense to me. Ace...

especially since all this data is in the nether regions of the globe and I don't care how many plane drops they do, they can't sample all of the energy and can't get the data over northern canada that so often messes up the models.

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Interesting. Here is the Weather Channel forecast for the Southern Poconos:

Jan 25 TuesdayA few snow showers. Highs in the low 20s and lows in the mid teens.Jan 26 WednesdayWindy with a wintry mix of precipitation. Highs in the upper 20s and lows in the upper teens.Jan 27 ThursdayA few snow showers possible, windy. Highs in the low 30s and lows in the mid teens.

What forecast model at this point is bring p-type issues this far west (Albrightsville, PA)? From what I can see any p-type issues would be on the coastal plain on eastward. Am I missing somehting?

D

Got me, maybe the Ukie and some individual Ensemble members from various models?

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Why are we assuming that the high WILL slide off the coast at the time that it is shown to do so? Isn't the high sliding off the coast a product of the forecast made by the model in the previous frames? Which means that can change quite a bit between now and 120 hours. Especially this year, everyone should realize how LOOOONG 120 hours really is when predicting a snowstorm. Not saying this can't be a driving rainstorm, but taking a high sliding off the coast at the exact time it is shown to do so as fact 5 days out doesn't make sense to me. Ace...

This. We are just going to have to wait and see what happens I guess.

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Interesting. Here is the Weather Channel forecast for the Southern Poconos:

Jan 25 TuesdayA few snow showers. Highs in the low 20s and lows in the mid teens.Jan 26 WednesdayWindy with a wintry mix of precipitation. Highs in the upper 20s and lows in the upper teens.Jan 27 ThursdayA few snow showers possible, windy. Highs in the low 30s and lows in the mid teens.

What forecast model at this point is bring p-type issues this far west (Albrightsville, PA)? From what I can see any p-type issues would be on the coastal plain on eastward. Am I missing somehting?

D

Don't look at the Weather Channel for a forecast. You'll likely be in great shape up there in Carbon.

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There's a lot of E-W spread in the H5 charts, but they're all really amplified. Whoever gets snow is going to get dumped on.

while we all know that lots of changes can happen on the next few days worth of runs........my question is.......are the models better at predicting certain factors over others.......for example are they more accurate (approx 2-3 days out) at knowing the actual storm track depiction or are they better at knowing daytime temps or are they better at knowing the location of the high to the north etc??? i'm just curious if the models are better at certain conditions over others???

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We do have a gulf stream with 40-50 degree water temps well offshore you know. Don't think for a second a storm like this cant bring in this type of marine influence with a strong, prolonged easterly fetch and a departing arctic high. Doesnt really matter if water temps are 35 degree for the first few miles on the coast. And yes, the euro has a lot more low level warmth, or at least would imply it, and does not mean MECS totals verbatim.

Then again in this historic winter en route, who the hell knows what will happen. You get the feeling If it can snow, it will find a way in these winters.

1000000000000000000000000000000pct

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Interesting. Here is the Weather Channel forecast for the Southern Poconos:

Jan 25 TuesdayA few snow showers. Highs in the low 20s and lows in the mid teens.Jan 26 WednesdayWindy with a wintry mix of precipitation. Highs in the upper 20s and lows in the upper teens.Jan 27 ThursdayA few snow showers possible, windy. Highs in the low 30s and lows in the mid teens.

What forecast model at this point is bring p-type issues this far west (Albrightsville, PA)? From what I can see any p-type issues would be on the coastal plain on eastward. Am I missing somehting?

D

Who knows why TWC puts anything on their website. There could be a blizzard progged and it will say 'Snow Showers' lol. I can still remember when local on the 8s was about as good as it got for getting weather info, but those days are long gone. They are about as useful as paper phone books at this point...

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while we all know that lots of changes can happen on the next few days worth of runs........my question is.......are the models better at predicting certain factors over others.......for example are they more accurate (approx 2-3 days out) at knowing the actual storm track depiction or are they better at knowing daytime temps or are they better at knowing the location of the high to the north etc??? i'm just curious if the models are better at certain conditions over others???

Each model has its strengths, weaknesses and biases, but one thing I like to keep in mind is that the further you go up in the atmosphere, the less influence the boundary layer has (mesoscale features, frictional effects, etc.) and therefore the more likely the models are to have a clue at a given timeframe. That said, they can all be spectacularly terrible from BL to tropopause. :)

This is why I like to focus more on troughs/ridges, vortmaxes and jet streaks in the medium range.

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A lot being made in this thread about the 50/50, block, etc but it all comes back to timing, and right now the warmer solutions are hanging energy back in the trough and not consolidating it so once the energy does come through it spawns the gulf low later, further west, and by that time the setup in the north atlantic has gone down hill. You can see it very clearly with the GFS 84 hours 12z vs NAM 84 hours 18z.

gfs_namer_090_500_vort_ht.gif

gfs is consolidated and thus quicker

nam_namer_084_500_vort_ht.gif

NAM has the energy split and coming down the back of the trough still and would probably be on the western side extrapolated

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Each model has its strengths, weaknesses and biases, but one thing I like to keep in mind is that the further you go up in the atmosphere, the less influence the boundary layer has (mesoscale features, frictional effects, etc.) and therefore the more likely the models are to have a clue at a given timeframe. That said, they can all be spectacularly terrible from BL to tropopause. :)

This is why I like to focus more on troughs/ridges, vortmaxes and jet streaks in the medium range.

i guess the main focus of my question was predicting the location of the high to the north come storm time which i take from your answer that it will probably be correctly modelled by sat or sun??

thanks a bunch!!

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So....been out for most of the day...how are we doing with our storm for next week? Are we still looking at a Monday night/Tuesday event. Luckily, in Berks county I am not expecting p-type issues.

I would expect a lot of precip type issues in Berks County, however Lancaster County seems to be right in the jackpot ;)

Haha just kidding, I'm excited for this storm and it's going to be cool to see it come together for whoever it hits!

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Hey, will the models change several more times? I really need 50 more people to post this tired cliche that contributes nothing but inflated post count of the thread to be sure.

thx

I believe the models will change 50/50 more times, which of course is one time, and give my block 45" while surrounding areas spike to 4-5 c or so.

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Just some of my thoughts regarding the upcoming system.

One thing that really annoys me is that there are individuals in this thread stating that a mecs/hecs can't happen and discounting such a solution, while advocating the other solution, as if it has already occurred. One thing I saw mentioned is how the current depiction cannot support a major snowstorm, because the high slides east and the warm air intrudes into the region. Yes that would be correct if the current solution depicted by some models transpires. Let's no forget things change and already have/will continue to. A few days ago a snowstorm was not even a reasonable prospect/on the table. So how could it be we have evolved to the current point in time, where the solution seems much more more convoluted and far from determined? The atmosphere is undergoing changes and the models are adjusting accordingly. It is a catch up game.

The biggest thing I notice that is evident on most models that was not even apparent a few days ago is blocking. The depictions of this block at H5 on many models has become more apparent and the signal has become stronger the last few days. The models keep increasing the ridging over Greenland and the block seems healthier as the days progress, this wasn't even shown on most models just a few days ago. This is what is causing the changes at the surface and ultimately causing the confusion. Take the NAM and GFS depictions respectively at 500mb at 72hrs. These features weren't even apparent just a few days ago. I don't see why models can't continue to pick up on these features and better illustrate them as time progresses. Just think a few days ago we were talking about an inland runner, now the conclusion isn't as clear.

The blocking I mention is crucial because it will be important in preventing the system from cutting west, or allowing the HP to slide out to sea as quick, or allow rapid WAA ahead of the LP. Confluence will be very important. There are other factors however that I also think should be noted. Most models depict a healthy ridge out west (+PNA) which would argue against any energy hanging back west and a quicker overall progression. The large ridge forces the cold air downstream into the trough in the eastern US and forces the pattern/trough to progress east. MJO is at least favorable and the state of the NAO is improving.

Now I am not forecasting a large snowstorm, I was simply appalled by the posts stating that there is no way this can be a mecs/hecs for the east coast. Let's remember how we even got to the point of discussing this potential, things have changed and continue to change. What was never even a thought a few days ago, now holds some merit and is definitely deserving of attention. I would like to continue to see the improvements at H5 continue, and being that we are still a few days out, it is not out of the realm of possibilities. And if anything the biggest factor might simply be that everything seems to be going right this winter for some areas, whose to say that changes. There was a point last year where I said to myself, no way in hell the mid atlantic is going to get another MECS, well guess what, it happened multiple times.

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