NYC/PHL Jan 18-19 Potential Threat Thread

[Analog96]

The bust potential on Miller Bs is massive....not so much for NYC but the corridor from TTN-BWI-DCA its very high as we have seen with the 12/30/00 event and the Boxing Day one this year....many of the NYC forecast busts pre 1990s occurred with Miller B events....even during the 60s-80s most of the Miller As were well forecast.

That's because in the 1960s-80s, the early, primitive computer models didn't have too much trouble picking up already well-formed Miller As. Predicting where a Miller B will develop is a lot more difficult.

[tornadojay]

<br />I am supposed to be subbing Tuesday at the local high school, and even down here at 350' elevation 10 miles north of NYC, I think we may have a nasty situation. I wouldn't be surprised to see delays in Southern Westchester and cancellations in Northern Westchester. Latest GFS shows around 2" of snow here lasting until around 7am, then potentially some ice, and a transition to rain in late morning. Perfect timing to cancel school...;gt;

If it's anything like the school districts in rockland county, you can be sure they will close school... At the very least a 2 hour delay. I think it will be messy up where we are

[isnice]

What are you talking about? I don't know about you, but I have 12-15" of snow still on the ground in Southern Westchester, including a crusty glacier from the Boxing Day Blizzard. There's no way we're going to lose all of that, or even most of it, with the Tuesday storm. Bitterly cold temperatures tomorrow night around 10F are going to freeze the snowpack solid....we rate to get 1-3" of snow, at least, from the SW flow event, topped by a glaze of icing that will seal the snowpack. The GFS only shows .5" rain on Tuesday/Wednesday morning, and that falls with temperatures in the upper 30s and low 40s, as we have a cold antecedent airmass with CAA on the backside of the clipper, and then a coastal forming which locks in E/NE winds that keep us fairly chilly. I am growing tired of the pessimistic comments which have no base in actual meteorology...this isn't going to be a snowpack killer especially for those of us in the suburbs.

The last storm was pretty sweet here in Dobbs Ferry, 14.5" with insane snowfall rates. Even NYC had 9.1"; that's a big storm, although it doesn't seem as impressive given all the huge snowstorms we've had since March 2009. We've done great in Miller Bs recently...2/25 Snowicane last year was over 20", January 2005 was like 14", etc...Miller As are awesome to watch as they crawl up the coast although plenty of them have whiffed here including the 2/5 and 1/30 storms last winter.

I'm not being pessimistic, I'm being realistic. After the Boxing Day Blizzard, we had temps in the upper 30's and low 40's for a couple days in a row. My snowpack (yes, in NYC's elevated western suburbs) went from 18" to about 3". You'd be surprised what 24 hours of 40 degree weather can do to a snowpack recently reduced by rain. It's simple science. By the way, here's the hour 90 forecast of the GFS:

[SnoSki14]

We may lose all or most of our snow pack but we also have to remember that our snow pack has become very hard and like cement. I mean the warm up after the boxing day storm occurred only a few days after the storm. A 2 week plus snow pack is a lot tougher than a few day old snow pack, plus temperatures may not be as high as during the late December/early January thaw.

[SnowGoose69]

The 00Z GEM only differs by 30mb off the NJ coast at 130-140 hours compared to the GFS

[atownwxwatcher]

We may lose all or most of our snow pack but we also have to remember that our snow pack has become very hard and like cement. I mean the warm up after the boxing day storm occurred only a few days after the storm. A 2 week plus snow pack is a lot tougher than a few day old snow pack, plus temperatures may not be as high as during the late December/early January thaw.

There really is not a thaw coming... temps in the 30s and perhaps some lower 40s in SNJ...

Not really seeing that as a thaw...

[Analog96]

The 00Z GEM only differs by 30mb off the NJ coast at 130-140 hours compared to the GFS

The GEM does like to overdo things...

[mattinpa]

The 00Z GEM only differs by 30mb off the NJ coast at 130-140 hours compared to the GFS

Are you saying the GGEM is showing a stronger storm?

[SnowGoose69]

Are you saying the GGEM is showing a stronger storm?

No storm, it has a 1025mb high there.

[Stephen Turner]

The 00Z GEM only differs by 30mb off the NJ coast at 130-140 hours compared to the GFS

what exactly does that mean and show?

[nzucker]

If it's anything like the school districts in rockland county, you can be sure they will close school... At the very least a 2 hour delay. I think it will be messy up where we are

They try not to close here if it's just a minor event, but I think the timing of this is perfect for a delay in Southern Westchester and a cancellation in Northern Westchester. Roads are also going to be extremely dangerous because we are supposed to have a low of 10F tomorrow night and a high of only 22F Monday, which means that road surfaces will become cold. Whatever snow falls Monday night will accumulate immediately with temperatures in the low 20s, and the GFS doesn't change us over until 7-8am Tuesday morning, and then we get probably 1-2 hours of freezing rain. That's a lot of frozen precipitation during the time when buses are sent out and parents are driving their kids to school.

I'm not being pessimistic, I'm being realistic. After the Boxing Day Blizzard, we had temps in the upper 30's and low 40's for a couple days in a row. My snowpack (yes, in NYC's elevated western suburbs) went from 18" to about 3". You'd be surprised what 24 hours of 40 degree weather can do to a snowpack recently reduced by rain. It's simple science. By the way, here's the hour 90 forecast of the GFS:

My snowpack went from 12" to around 4" in the New Year's blowtorch...I didn't get that much from the storm, only 13", so it was a bit easier to melt. It was a completely different situation though; I had temperatures of 40/21, 44/30, 52/33, 48/34. That's four days of well above average temperatures, a much longer stretch and with much warmer temperatures than this time around. I don't know about your backyard, but it was 45-50F for three days in a row here around New Year's; we had less snow on the ground than now, and yet it still didn't completely melt.

The Tuesday storm is a very different beast. We're getting 2-3" of snow, then a period of freezing rain, and then some rain. The front-end dump of snow/ice is going to build up the snowpack and add a crust of ice to the top, which makes it much more difficult for the rain to penetrate. The GFS and ECM only show about .5-.75" QPF for the rainstorm, that's not a ton of rain to melt a foot of snow. Also, the torch is short-lived...we probably get up to 40F by late afternoon Tuesday and are back below freezing by late Wednesday evening. At 90 hours (Wednesday 1pm), the GFS has 850s of 0C in NYC; that means we're all getting below freezing that night as cold air advection is swift with the brutal airmass over Canada around the PV.

[Wannabehippie]

I agree completely. I prefer snow over rain, but rain over sleet/freezing rain.

I'm rooting for straight up rain vs. any zr........zr is no good for anybody. Hopefully the Friday potential can come together a bit better.

[sferic]

January 1978, the NYC snowstorm before the Feb 1978 biggie and Feb 9, 1969, were they miller a or B?

I do remember with both 2-4 inches were forecast switching over to a wind swept heavy rain; we all know how that turned out, I'd just like to know the proximity of those storm to the NYC area; they both passed east of NYC, but how close was the center?

Feb 1969, schools closed the next day, 15 inches in Brooklyn.

Jan 1978, up to the end Accuweather was convinced of the changeover, yup, 10 minutes of sleet at the end, No rain as I recall.

[clindner00]

Any update on the euro yet or did people give up on this storm?

[tombo82685]

Any update on the euro yet or did people give up on this storm?

pretty much the same, front end slop over to rain, temps rise into the 40s... with like .5 of rain

[clindner00]

pretty much the same, front end slop over to rain, temps rise into the 40s... with like .5 of rain

So the Euro is standing it's ground then. I heard the gfs has been showing primarily snow and ice for south central pa

[NortheastPAWx]

So the Euro is standing it's ground then. I heard the gfs has been showing primarily snow and ice for south central pa

Yeah but with progressively less precip.

[atownwxwatcher]

So the Euro is standing it's ground then. I heard the gfs has been showing primarily snow and ice for south central pa

ECM has warmer 850s generally ...

[clindner00]

ECM has warmer 850s generally ...

blah......Matt, are you siding with NWS for south central PA where they are giving York County mainly snow and sleet or r u closer to the Euro? I have all of my coworkers asking me about weather forecasts but I have a hard time believing that we won't get primarily rain in the lower susquehanna valley

[atownwxwatcher]

blah......Matt, are you siding with NWS for south central PA where they are giving York County mainly snow and sleet or r u closer to the Euro? I have all of my coworkers asking me about weather forecasts but I have a hard time believing that we won't get primarily rain in the lower susquehanna valley

Check my blog tonight after about 4 AM as that is when i will be issuing preliminary map and latest thoughts on this and potential event or non event afterwards!

[clindner00]

Check my blog tonight after about 4 AM as that is when i will be issuing preliminary map and latest thoughts on this and potential event or non event afterwards!

I definitely will since I do everyday because you seem to be more realistic than most pro mets. (no offense intended to them)

[SnowGoose69]

This event is basically DOA ....the high moves out too quickly and is already positioned way too far east when any overrunning begins...the #1 analog for this event on CIPS is now 1/17-1/18 2008....that says enough right there....the good news is we have potential after it. ...the Euro was correct again (no surprise there) before the GFS ever caught on.

[mattinpa]

This event is basically DOA ....the high moves out too quickly and is already positioned way too far east when any overrunning begins...the #1 analog for this event on CIPS is now 1/17-1/18 2008....that says enough right there....the good news is we have potential after it. ...the Euro was correct again (no surprise there) before the GFS ever caught on.

I think the interior should still watch it. The GFS also hasn't given up on its couple inches of snow close to the cities. Certainly agree that this won't be a major event and the real potential is after.

[nzucker]

I think the interior should still watch it. The GFS also hasn't given up on its couple inches of snow close to the cities. Certainly agree that this won't be a major event and the real potential is after.

The event is DOA for a major snowstorm, but no one was ever expecting that with the primary tracking so far west.

The threat is for 2-4" of snow followed by ice in the NW suburbs, so I'm paying careful attention especially since I'm supposed to work Tuesday morning. I think the potential for an ice storm in NW NJ and the Lehigh Valley of PA should definitely be monitored carefully, seems as if people are sort of ignoring the ominous signs for a nasty event.

[IsentropicLift]

not sure why eveyone is so anxious to get a low end advisory snow event after the storms we just had and what seems to be in store towards the beginning of the extended range. I'm personally in favor of a nice ice storm. If we can't get the snow, we might as well get something less boring than plain rain.

[nzucker]

pretty much the same, front end slop over to rain, temps rise into the 40s... with like .5 of rain

Tombo, how much QPF does NYC get before the changeover? How about in my area like 25 miles north of Central Park?

Is there an icing threat for the NW suburbs as the 850 line moves north but 2m temperatures stay cold?

[IsentropicLift]

The event is DOA for a major snowstorm, but no one was ever expecting that with the primary tracking so far west.

The threat is for 2-4" of snow followed by ice in the NW suburbs, so I'm paying careful attention especially since I'm supposed to work Tuesday morning. I think the potential for an ice storm in NW NJ and the Lehigh Valley of PA should definitely be monitored carefully, seems as if people are sort of ignoring the ominous signs for a nasty event.

Perhaps when the NWS puts out watches tommorrow it will get everyone's attention. They may very well hold out until the evening but the threat is definitly on the table and cant be ignored.

[SnowGoose69]

The event is DOA for a major snowstorm, but no one was ever expecting that with the primary tracking so far west.

The threat is for 2-4" of snow followed by ice in the NW suburbs, so I'm paying careful attention especially since I'm supposed to work Tuesday morning. I think the potential for an ice storm in NW NJ and the Lehigh Valley of PA should definitely be monitored carefully, seems as if people are sort of ignoring the ominous signs for a nasty event.

If this evolved more as a SW flow event as the models initially had indicated more so it would have more potential for producing front end snows...as it turns out this is more of a coastal low scenario with bad positioning of the high...almost everything that could go wrong with this event has so far...the thing is this has been one of those winters where things have found ways to turn snowy so we cannot ditch everything yet but it doesnt look good.

[IsentropicLift]

It's not going to snow 12 inches with every storm. We have the potential here for a major winter storm and a very icy one at that and I for one am very excited. Snow lovers only have a week to wait.

[nzucker]

It's not going to snow 12 inches with every storm. We have the potential here for a major winter storm and a very icy one at that and I for one am very excited. Snow lovers only have a week to wait.

Yes, I sort of enjoy these marginal set-ups since it's a learning experience in terms of how to forecast p-type and which areas hold onto low-level cold best. It also will be interesting to see if this evolves into a major ice storm for parts of NW NJ, E PA, and SE NY. The set-up is certainly there with a high slowly retreating, deep snowpack and antecedent cold in place, and a low pressure cutting to the west. It doesn't have the synoptics of a huge ice event but could be dangerous, and it will coincide with the morning commute for many so that raises the threat level.

I think there will be some snow next weekend....whether it is an arctic clipper or a Miller A, there's definitely some potential out there. We have a 50/50 low, +PNA, great airmass and a vort tracking across the Plains, all the ingredients we need for a major snowfall. Plenty of time to discuss it though.