E PA/NJ/DE Winter 2020/2021 OBS Thread

[Animal]

54 minutes ago, MGorse said:

The model snow maps, especially the SLR 10:1, should be banned from the internet or at least so the public does not see them.

NWS should partner with Twitter and Facebook for one of those alert messages that it is censored.

[Moderately Unstable]

Four thoughts--

 

1) I'm excited. Semantics aside, it's been TWO YEARS since we had an interesting winter weather setup in the Philly area of any kind. I don't care if we get 6", 16", 20"...I just want to see some white stuff falling out of the sky!

2) In the short term, the 12z NAM and other short-range guidance indicate a low-impact rain-snow for the Philly metro wrt Monday's system. The 12z GFS is similar, with a widespread 1"-2" projected, likely not going to stick though due to temps. Snow rate will not be sufficient to facilitate significant air cooling due to latent energy release of melting so seems unlikely to be one of the sneak storms that drops an inch or two that no one expected to see. MOS and other guidance suggest temps could top in the low 40s, that may be a high bet given the cloud cover (& limited evap cooling) so perhaps upper 30s makes more sense. It should be stated that were we to get a widespread trace to 1-2" of snow early this week, the increase in albedo could locally result in a marginal temperature decrease. In this context, that may matter (33 vs 32 degrees type of thing)--but, again, will depend on how that whole solution verifies. Tracing back, the models come to a snow conclusion based on freezing in the 850-700 mb level, with marginal above freezing temps below.  Similarly, the evolution and track of the first low and its impact on the dynamics it brings in behind it somewhat matter on whether we in fact are looking at a foot maker, or beyond into the GFS weenie-utopia land of 20+. 

 

3) The second storm right now is a semi-classic miller B type setup. When I look at Miller B's (and As for that matter)... I like to check out the NAO first.  The NAO is marginally negative right now and progged to become much more negative over the next few days. That both leads me to more "lingering" solutions, and to a more messy p-type analysis due to more northward progression of the low. This means the system won't end up busting out to sea--it could "bust" warm if it goes further north, but it ain't a non-event. This also applies to the first storm, and may be why the signal for that is getting a bit more amplified with time.

 

4) A fairly strong jet streak will enhance precip in the mid-week storm, and could lead to enhancement of banding through some extra forcing for ascent.Thus, if we did maintain the cold solution, we'd probably see a couple of mesoscale corridors setup where you'll see the real maximal snow amounts. This seems plausible regardless of the specific "where" the low eventually tracks. 

 

 

[Animal]

Afternoon afd from mt holly NwS is honking for significant snow event far northern Delaware, North East MD and north. Decent read overall. 

 

[Jsdphilly]

Feels like I have only been able to lurk for 2 years. Excited to be back tracking with all of you! Hopefully my 2 year old will be able to see her first real snow from this!!

[MGorse]

50 minutes ago, Animal said:

NWS should partner with Twitter and Facebook for one of those alert messages that it is censored.

Interesting idea, but that will likely not happen.

[Ralph Wiggum]

56 minutes ago, Moderately Unstable said:

Four thoughts--

 

1) I'm excited. Semantics aside, it's been TWO YEARS since we had an interesting winter weather setup in the Philly area of any kind. I don't care if we get 6", 16", 20"...I just want to see some white stuff falling out of the sky!

2) In the short term, the 12z NAM and other short-range guidance indicate a low-impact rain-snow for the Philly metro wrt Monday's system. The 12z GFS is similar, with a widespread 1"-2" projected, likely not going to stick though due to temps. Snow rate will not be sufficient to facilitate significant air cooling due to latent energy release of melting so seems unlikely to be one of the sneak storms that drops an inch or two that no one expected to see. MOS and other guidance suggest temps could top in the low 40s, that may be a high bet given the cloud cover (& limited evap cooling) so perhaps upper 30s makes more sense. It should be stated that were we to get a widespread trace to 1-2" of snow early this week, the increase in albedo could locally result in a marginal temperature decrease. In this context, that may matter (33 vs 32 degrees type of thing)--but, again, will depend on how that whole solution verifies. Tracing back, the models come to a snow conclusion based on freezing in the 850-700 mb level, with marginal above freezing temps below.  Similarly, the evolution and track of the first low and its impact on the dynamics it brings in behind it somewhat matter on whether we in fact are looking at a foot maker, or beyond into the GFS weenie-utopia land of 20+. 

 

3) The second storm right now is a semi-classic miller B type setup. When I look at Miller B's (and As for that matter)... I like to check out the NAO first.  The NAO is marginally negative right now and progged to become much more negative over the next few days. That both leads me to more "lingering" solutions, and to a more messy p-type analysis due to more northward progression of the low. This means the system won't end up busting out to sea--it could "bust" warm if it goes further north, but it ain't a non-event. This also applies to the first storm, and may be why the signal for that is getting a bit more amplified with time.

 

4) A fairly strong jet streak will enhance precip in the mid-week storm, and could lead to enhancement of banding through some extra forcing for ascent.Thus, if we did maintain the cold solution, we'd probably see a couple of mesoscale corridors setup where you'll see the real maximal snow amounts. This seems plausible regardless of the specific "where" the low eventually tracks. 

 

 

You need to post here more often. Thanks for sharing your thoughts.

[RedSky]

Low makes it inland to Vineland this GFS run uh ohs

 

[Ralph Wiggum]

Losing that warm fuzzy feeling. 18z GFS is a decent tick N and W and quite a bit of mixing being shown. Jackpot shifted central PA. 

[Ralph Wiggum]

Dont like seeing the trof slow down more each run allowing the confluence to weaken and the hp to escape. Curious to see if the ens agree with the op.

[Animal]

9 minutes ago, Ralph Wiggum said:

Losing that warm fuzzy feeling. 18z GFS is a decent tick N and W and quite a bit of mixing being shown. Jackpot shifted central PA. 

Lots of rain on my street!!

it’s an off cycle run of the goofus.

 

[Animal]

10 minutes ago, RedSky said:

Low makes it inland to Vineland this GFS run uh ohs

 

Hopefully just a blip.

let’s wait for the ensembles!!

[ChescoWx]

There will be a couple more of these 18z type runs - details to be ironed out....when the EPS is honking I am buying at least a significant snowstorm (over 6") for many from the I95 corridor N and W....keep in mind major 10" + storms are very rare in this area. I will be posting top 10 shortly for Western Chester County PA shortly

[snowwors2]

18z Gefs should make you feel better‼️

[Animal]

Any event I joined cocohoras for reporting rain,sleet snow.

it’s honestly a serious group. 

my handle is 1.7 w upper chi Chester 

[Moderately Unstable]

Lots of good discussion right now on this whole setup in the Mid Atlantic forum. But, yeah, I mean look run-to-run is going to look different, that's the game (makes it fun)! EPS 18z looked solid, made 18z gfs look like an outlier. 18z gefs was reasonable as well. Still plenty of time--we're nearing the place where the op models and their ensembles converge enough to switch over to the op (though just to throw it out there--there's never a *bad* time to use an ensemble...averaging perturbations does well to ameliorate the woes of chaos theory at hour 100 and also at hour 10). Going to be a solid storm for the Philly region regardless, this is more a question imho of weenie solution MECS vs a more standard SECS. I want my MECS (unfortunately I don't think HECS is in the cards here using the statistical 1:10 year standard, but hey, I'll keep hoping).

 

Suggest poss creating a dedicated topic if the 00z runs continue to indicate or trend for major storm (really seems warranted regardless now).

[penndotguy]

19 minutes ago, Moderately Unstable said:

Lots of good discussion right now on this whole setup in the Mid Atlantic forum. But, yeah, I mean look run-to-run is going to look different, that's the game (makes it fun)! EPS 18z looked solid, made 18z gfs look like an outlier. 18z gefs was reasonable as well. Still plenty of time--we're nearing the place where the op models and their ensembles converge enough to switch over to the op (though just to throw it out there--there's never a *bad* time to use an ensemble...averaging perturbations does well to ameliorate the woes of chaos theory at hour 100 and also at hour 10). Going to be a solid storm for the Philly region regardless, this is more a question imho of weenie solution MECS vs a more standard SECS. I want my MECS (unfortunately I don't think HECS is in the cards here using the statistical 1:10 year standard, but hey, I'll keep hoping).

 

Suggest poss creating a dedicated topic if the 00z runs continue to indicate or trend for major storm (really seems warranted regardless now).

That’s kinda been the dagger in the storm, no one wants to start it and be the one that killed the threat Lol. 

[Birds~69]

15 minutes ago, penndotguy said:

That’s kinda been the dagger in the storm, no one wants to start it and be the one that killed the threat Lol. 

I would wait till later tomorrow at the earliest...let's just focus on the next couple runs and hopefully we're still in good shape.

[LVblizzard]

Don't sleep on Monday. It's looking like there will be a stripe of some pretty solid amounts somewhere between I-80 and the M-D line.

[Newman]

1 minute ago, LVblizzard said:

Don't sleep on Monday. It's looking like there will be a stripe of some pretty solid amounts somewhere between I-80 and the M-D line.

Agree, especially if we look at the latest 0z NAM suite. Both the 12k and 3k drop a solid couple inches across Berks and the Lehigh Valley.

[Birds~69]

Just now, LVblizzard said:

Don't sleep on Monday. It's looking like there will be a stripe of some pretty solid amounts somewhere between I-80 and the M-D line.

True. Many will see something but more N/W/Lehigh Valley. That could have it's own separate thread?

[Albedoman]

I just cannot understand why Mt.  Holly is gun shy about Mondays snow event. The NAM has been consistent now for days on showing at least 5 " in for the LV but tonights forecast says  less than 1/2 inch.  Evap cooling will overtake and they keep ignoring this possibility. I have seen it so many times in the LV in this situation. The ground temps are still cool as demonstrated by the ground by the dense fog advisory tonight?  The model indicates at least an advisory level event for days now.  Honestly, if Mondays event drops 4 in like I am expecting plus another 16+ in on Wednesday. it should set the record for the most snow in December for the LV. What a Christmas gift

Additionally, the Wednesday snow event could be some major snow drifting issues that we have not seen here in nearly a decade or longer.  It could be a storm to remember for sure. Nobody has brought that up along with a good chance of thundersnow has the low bombs out.

 

[Heisy]

Anyone in the far Burbs got a place I could come stay at and chase?! 

[Birds~69]

6 minutes ago, Albedoman said:

I just cannot understand why Mt.  Holly is gun shy about Mondays snow event. The NAM has been consistent now for days on showing at least 5 " in for the LV but tonights forecast says  less than 1/2 inch.  Evap cooling will overtake and they keep ignoring this possibility. I have seen it so many times in the LV in this situation. The ground temps are still cool as demonstrated by the ground by the dense fog advisory tonight?  The model indicates at least an advisory level event for days now.  Honestly, if Mondays event drops 4 in like I am expecting plus another 16+ in on Wednesday. it should set the record for the most snow in December for the LV. What a Christmas gift

Additionally, the Wednesday snow event could be some major snow drifting issues that we have not seen here in nearly a decade or longer.  It could be a storm to remember for sure. Nobody has brought that up along with a good chance of thundersnow has the low bombs out.

 

I think they're going with 1-2" now....still probably too low. (Berks/Lehigh)

Winds 40+mph will make this a fun event. Always enjoy high winds/drifting with heavy snow...

[Birds~69]

GFS looks like a nice hit...incoming.

[Birds~69]

Really couldn't look better...

[Moderately Unstable]

Yes, the 00z run is phenomenal. I'm so excited I actually can't think of what to type right now . But you're right, this is as good as it gets. 

[MJO812]

Cmc crushes philly

[RedSky]

18 minutes ago, Birds~69 said:

Really couldn't look better...

Can too- try the kuchera totals.

 

 

[LVblizzard]

The GFS is nice but I’m suspicious with how weak it looks at 500mb. I think it’s up to its old tricks and moving the storm east off the coast too quickly.

[MJO812]

6 minutes ago, LVblizzard said:

The GFS is nice but I’m suspicious with how weak it looks at 500mb. I think it’s up to its old tricks and moving the storm east off the coast too quickly.

Gefs is further east