NYC/PHL 1/25-27 potential Part III

[TheTrials]

for all the worry about the HP placement, looks mighty fine on the euro mean. Another poster pointed out the NAM, new high feeding in and you can see 850 temps and surface temps cooling down western PA. If the NAM track that low off the coast, it may just work.

[Voyager]

That is a fooking beast at 84. Sim radar looks awesome.

Yes, but where does it go from there?

[_AR_]

12Z ECMWF ensembles:

[MJO812]

GGEM ensemble mean is way east of the op run.

[NortheastPAWx]

Yes, but where does it go from there?

Based on that new high coming down it probably follows the EURO and GFS and also goes well east. Likely another PHL-NYC special.

[TheTrials]

I think the DGEX is going to be very nice for everyone. The NAM is taking that low up to the carolina coast and based on pressure falls probably to or just south of he BM. Lots of cold air building on the back side and a 1030 HP sitting north of Maine.

[jm1220]

for all the worry about the HP placement, looks mighty fine on the euro mean. Another poster pointed out the NAM, new high feeding in and you can see 850 temps and surface temps cooling down western PA. If the NAM track that low off the coast, it may just work.

You can also see the dynamic precip-driven cooling down the slopes of the Apps. With that track, it would likely be very snowy for many of us. Given the 500mb chart, it would likely continue sliding NE and not cut north.

[A-L-E-X]

The 0c 850 line never gets above Philly through the end of the NAM run.

18z nam doesn't look bad to me...would probably look like the 6z DGEX

yes 850s get close to above 0 to NJ/NYC at 84 hrs, but look how they crashed back down further south. at 78 hours the 0C line was well north and west of dc/bwi, at 84 the 0C line has retreated toward SEVA.

Agreed. Wes seems to like the temp profiles on the NAM-- he said that the 850s collapse SE as the precip starts.

[Maximum lawman]

Yeah, this is what the models seem to be keying on today.

If I had to make a forecast for KPHL today and couldn't hedge my bets, I'd say this is predominantly a rain event for PHL, and a big one. My reasoning is that the GFS has actually been very good - going all the way back to through the fall-- at sniffing out big precip events in the 144 hour range. When the storm was 7 days out, that's when the GFS was putting out the big precips numbers (I should note that's also when the EURO was putting out big numbers as well - as all rain while the GFS was all snow. You may recall that at the time the consensus was the EURO was more believable than the GFS. The fact that we are down to less than a quarter inch in QPF on the GFS 72 hours out is ABSOLUTELY consistent with prior coastals these last few months -the GFS has lost all or almost all the precip for PHL in every single storm. In fact and I haven't done this, but I'd bet that if you verified the 144 hour forecast it was better than anything outside of 48 hours. In this case, big precip means warmth.

[Voyager]

Based on that new high coming down it probably follows the EURO and GFS and also goes well east. Likely another PHL-NYC special.

Hopefully later runs back away from the idea of that new high.

[A-L-E-X]

You can also see the dynamic precip-driven cooling down the slopes of the Apps. With that track, it would likely be very snowy for many of us. Given the 500mb chart, it would likely continue sliding NE and not cut north.

Hopefully this is the start of some sort of consensus lol.

[earthlight]

NAM already has 925mb temperatures above 0c for pretty much everybody south of HPN at 84 hrs. 4 c on ACY.

[mattinpa]

Hopefully later runs back away from the idea of that new high.

To some that high could be a savior, though. I hope all areas can cash in.

[A-L-E-X]

If I had to make a forecast for KPHL today and couldn't hedge my bets, I'd say this is predominantly a rain event for PHL, and a big one. My reasoning is that the GFS has actually been very good - going all the way back to through the fall-- at sniffing out big precip events in the 144 hour range. When the storm was 7 days out, that's when the GFS was putting out the big precips numbers (I should note that's also when the EURO was putting out big numbers as well - as all rain while the GFS was all snow. You may recall that at the time the consensus was the EURO was more believable than the GFS. The fact that we are down to less than a quarter inch in QPF on the GFS 72 hours out is ABSOLUTELY consistent with prior coastals these last few months -the GFS has lost all or almost all the precip for PHL in every single storm. In fact and I haven't done this, but I'd bet that if you verified the 144 hour forecast it was better than anything outside of 48 hours. In this case, big precip means warmth.

It usually does, because it means too much mild air has come in off the ocean and the Arctic high has eroded to cause that to happen. If I had to make a forecast today, it would be a "wintry mix" not all rain though, but more like a snow to rain to snow on the backside deal.

[Noreaster07]

Check out the new high dropping down at 81

http://mag.ncep.noaa..._wnd_precip.gif

meh its still east of 70 W

[Zir0b]

I like the northerly windstream over NY/PA

[Alpha5]

Euro ensembles are a BM track with .25-.5 QPF over NYC

SPag plots show the OP is slower and still slightly west than most of the ensemble members

[mattinpa]

For you guys yes...for people like me and Voyager it's hurting us though.

Hard to see how the NAM misses you, though, but we have to watch the seasonal trend. Seasonal trend would take it too east for me, too.

[Maximum lawman]

12Z ECMWF ensembles:

That's interesting. So If I'm interpreting this correctly, and I can't say I've thought about it before - the OP mean SLP is at the edge of its own guidance, e.g. if the st dev contains two-thirds of the plausible values for the mean, the Sw-NE orientation suggestsions there's lots of room for correction, both good and bad, but mostly bad (closer to the coast).

[A-L-E-X]

Euro ensembles are a BM track with .25-.5 QPF over NYC

SPag plots show the OP is slower and still slightly west than most of the ensemble members

Interesting-- sounds like that second high is making its presence felt. I would actually like a closer track to get our whole area in on the heavy stuff.

[TheTrials]

Looking at the NAM, it may start a little warm, but the projected track just using slp height contours would bring cold air in as it came north. What a juicy system.

[Alpha5]

Interesting-- sounds like that second high is making its presence felt. I would actually like a closer track to get our whole area in on the heavy stuff.

I should correct myself...that was only 1 frame

Total QPF from the Euro Ens has the .75 line cutting through NYC...more east, less west

And with a BM track

[Noreaster07]

For you guys yes...for people like me and Voyager it's hurting us though.

that high is the least of your worries, If there was 1040 high over NY state that might cause suppression but not a 1026 high northeast of Maine

[TheTrials]

Intense VV off the south coast. Notice a lot of dry air up north.

[A-L-E-X]

I should correct myself...that was only 1 frame

Total QPF from the Euro Ens has the .75 line cutting through NYC...more east, less west

And with a BM track

Hey thanks for posting those maps! One question though-- do those closed isobars denote where the low is on the EURO OP or the average of all the ensembles?

[Maximum lawman]

Interesting-- sounds like that second high is making its presence felt. I would actually like a closer track to get our whole area in on the heavy stuff.

I'm curious, because I haven't focused on that feature, but is the incoming high actually evolving into a stronger feature, or is it just that compared to the faster runs of the GFS the timiing is better? I asumme that it is stronger on the EURO given the 12z solution and the consistent EURO timing of the event, but I wonder what people have noticed on the other models.

[A-L-E-X]

that high is the least of your worries, If there was 1040 high over NY state that might cause suppression but not a 1026 high northeast of Maine

He seems to be worried about the next high that comes in behind that one.

[A-L-E-X]

I'm curious, because I haven't focused on that feature, but is the incoming high actually evolving into a stronger feature, or is it just that compared to the faster runs of the GFS the timiing is better? I asumme that it is stronger on the EURO given the 12z solution and the consistent EURO timing of the event, but I wonder what people have noticed on the other models.

I think it's a combination of both-- the timing (speed) and the strength of it. It's such a tenuous situation though, that a few mb in the low or the high can make a huge difference, not to mention the timing.

[A-L-E-X]

Then (and hopefully a met chimes in) why did the Euro seem to cave to the GFS on the 12z run, and more importantly, why the lack of precipitation for the inland areas? It seems with each model run, the cards are slowly being taken off the table north and west of I-81.

Im hoping for you guys that the EURO OP is just too dry with the QPF; from what Alpha said, the Ensembles seem to be somewhat wetter.

[NJwinter23]

NAM already has 925mb temperatures above 0c for pretty much everybody south of HPN at 84 hrs. 4 c on ACY.

I love how everyone in here elected to ignore this post lol. My concerns from yesterday with rain in the cities has not changed one bit. Though I'm a bit encouraged by the jump east with the euro, we still need a pretty specific track/strength solution to get all snow down our way with this setup