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And we're off - first threat for a few mangled flakes


earthlight

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Great post, and I agree with a lot of it, you do a great job of breaking it down. Two things. Rina is already showing rapid signs of weakening as the sheer is increasing. Her western edge is falling apart rapidly.

Secondly, while the euro does have a slow bias in the southern stream, it usually manifests itself it when they actually come out of the sw, this one swings down the eastern side of the rockies. Conversely, the gfs loves to rip sw's apart, so the truth may lie somewhere in the middle.

It's going to be fun watching this over the next few days.

Not really... I don't even really have a physical explanation for why the ECWMF weakens Rina so much in the next 24-48 hours. Shear remains fairly low and only really starts rapidly increasing beyond 48 hours to a magnitude that can induce weakening. The ECWMF pretty much from the get go is forecasting rapid degeneration, and this does not seem likely at least during the first 48 hours of the forecast.

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nice disco by Upton, even if the ECMWF verifed and we had the perfect track for snow, its stil most likely rain for NYC and coastal areas.

It's ok they'll play catch up, just like when the ice storm warning was issued on VD 2007 after there was already 3 inches of sleet on the ground.

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Not really... I don't even really have a physical explanation for why the ECWMF weakens Rina so much in the next 24-48 hours. Shear remains fairly low and only really starts rapidly increasing beyond 48 hours to a magnitude that can induce weakening. The ECWMF pretty much from the get go is forecasting rapid degeneration, and this does not seem likely at least during the first 48 hours of the forecast.

I edited when I relooked at it, but its clearly struggling compared to earlier, and its def. encountering something on the western side which is chipping away at it.

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I edited when I relooked at it, but its clearly struggling compared to earlier, and its def. encountering something on the western side which is chipping away at it.

Looks can be deceiving on IR, recon made a pass about an hour ago and found that the pressure had decreased 4mb since the last pass with slightly higher FL winds. There will be bursts of convection from time to time that will obscure the small eye, but the storm certainly isn't falling apart yet.

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Looks can be deceiving on IR, recon made a pass about an hour ago and found that the pressure had decreased 4mb since the last pass with slightly higher FL winds. There will be bursts of convection from time to time that will obscure the small eye, but the storm certainly isn't falling apart yet.

noted.

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Eh, i think thats more of a strong PV in central canada, rather than having a ULL over newfoundland.

Having a 50/50 low locked in place with a block downstream means there is a confluence zone in southeast Canada..Confluence in the upper levels makes for sinking air and high pressure at the surface, in this case, anchored across southeast Canada.

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nice disco by Upton, even if the ECMWF verifed and we had the perfect track for snow, its stil most likely rain for NYC and coastal areas.

Let us do the 'forecasting scales of justice' for this system, assuming the ECMWF is a perfect prog:

For coastal rain:

It is October after all (climatology).

Strong easterly winds in the low levels off a relatively warm ocean.

Nothing resembling a cold air mass to the north.

850 mb temperatures just below zero Celsius.

For any coastal precip ending as snow:

If the precip. is falling at hard enough rates, it could bring down just enough cold air to change precip. along the coast to snow, although the height anomalies aren't incredibly impressive.

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Let us do the 'forecasting scales of justice' for this system, assuming the ECMWF is a perfect prog:

For coastal rain:

It is October after all (climatology).

Strong easterly winds in the low levels off a relatively warm ocean.

Nothing resembling a cold air mass to the north.

850 mb temperatures just below zero Celsius.

For any coastal precip ending as snow:

If the precip. is falling at hard enough rates, it could bring down just enough cold air to change precip. along the coast to snow, although the height anomalies aren't incredibly impressive.

the winds when it could actually snow in NYC would be N,NNE, not easterly, for NYC.

Also, 850's are at least -4 in NYC when it would be snowing.

Lastly, thicknesses are about 530 or so in NYC with heavy precip still in the area.

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Let us do the 'forecasting scales of justice' for this system, assuming the ECMWF is a perfect prog:

For coastal rain:

It is October after all (climatology).

Strong easterly winds in the low levels off a relatively warm ocean.

Nothing resembling a cold air mass to the north.

850 mb temperatures just below zero Celsius.

For any coastal precip ending as snow:

If the precip. is falling at hard enough rates, it could bring down just enough cold air to change precip. along the coast to snow, although the height anomalies aren't incredibly impressive.

If the Euro were to verify, there would be a very sharp gradient between the coastal plain and the immediate suburbs..but I think the snow would get into the city for sure at the tail end of the system. There's just enough dynamic cooling to allow for it to happen, even despite the poor timing with the CCB overhead at 18z. The immediate suburbs probably pick up a few inches of snow on the grass.

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Weak 1004mb surface low over the 40/70 benchmark at 51 hours. All available levels are below freezing east of the city through 925mb...moderate precipitation falling. Looks like it may be snowing up in snywx land.

Temperatures are in the mid 30's west of the city and closer to 32 F in the interior.

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Weak 1004mb surface low over the 40/70 benchmark at 51 hours. All available levels are below freezing east of the city through 925mb...moderate precipitation falling. Looks like it may be snowing up in snywx land.

Temperatures are in the mid 30's west of the city and closer to 32 F in the interior.

looks great for interior sw ct.. there is a lot of elevation up here.. maybe be able to get a few inches from this if the nam holds true.. decent qpf once 850s crash..

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looks like 8pm - 2am thursday night quick burst of snow we'll see how hard it comes down to get any accums.. if nam shows this again tomorrow night . i will be pretty pumped about a very early accumulating snowfall for up here at least. last time i saw accumulating snow in october was over 10 years ago and it was just a coating on grass

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NAM is still extremely disjointed with the second storm--that upper air depiction at 84 hours has very little chance of bringing a surface low up the coast.

yeah its ugly, it still drags the first s/w with that first storm and leaves the 2nd storm hanging..the nam is almost always wrong at this range so maybe thats a good thing lol

more interested in the gfs

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Yeah the NAM has poor timing of the shortwaves to initiate a JMA/Euro scenario, but it's not as far off as the final result would suggest. I bet the SREFs show some hits. And it wouldn't shock me if the 06z, or any of tomorrow's runs, produced a grazing hit or better. This to me looks like so many of the failed model runs that subsequently evolve to a major coastal storm. A major storm is less likely than a non-event by definition, but I am not too discouraged by the 0z NAM.

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1925-26 wasn't that bad with two major snowstorms in one week in February...It had over 20" of snow cover after the second storm...

Bottom line the sampling is too small to really say one way or the other what winter will do based on October snowfall.

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