February 7th Storm Threat Discussion/Obs

[Baltimorewx]

1 minute ago, DCTeacherman said:

Where’s the big disagreement?  Seems to me like most models have a similar low track with similar temps.  

The QPF forecasts differ. GFS and Canadian are .3 or less for I95 and northwest while NAMS and I guess the euro are a uniform .5-.6 for most everyone 

[Bob Chill]

1 minute ago, DCTeacherman said:

Where’s the big disagreement?  Seems to me like most models have a similar low track with similar temps.  

Yea, I see nearly complete agreement on track and speed. NW side is the only thing really in question. I can see how those to the nw would perceive disagreement tho. Living on the edge is torcher

[Negnao]

2 minutes ago, snowmagnet said:

Well the Ukie and the RGEM regularly offered me about 13” last weekend, so they’ve lost my trust. Ended up with less than 6”. 

I’m not saying they’re good models. Just seems like they are keying in on a trend of a less amplified system. Doesn’t seem as much interaction early enough with the ULL and doesn’t intensity as rapidly as earlier runs a day or two ago. Results in a track slightly southeast and weaker than prior runs. 

[psuhoffman]

4 minutes ago, DDweatherman said:

Such nice disagreement not even 18 hrs before onset. Fun hobby we have. 

Part of that is due to models being much higher resolution then before. The differences are in these meso banding that guidance couldn’t have even seen 20 years ago. Everything would have looked smoothed like the JMA on TT. Then we had to use climo and history to guess at the meso features. And in some ways maybe that was better. If you know how to actually use the models correctly and adjust it’s good but if you’re a weekend weather worrier who just rips and runs with a model verbatim having these details shift around on every model every run will drive you crazy. 

[SnowDreamer]

7 minutes ago, Negnao said:

UK looks like the Rgem 

Please be careful about posting total accumulation maps contaminated by other events not in this thread. It doesn't really affect VA/MD in this instance, but better safe than sorry. 

[DDweatherman]

1 minute ago, psuhoffman said:

Part of that is due to models being much higher resolution then before. The differences are in these meso banding that guidance couldn’t have even seen 20 years ago. Everything would have looked smoothed like the JMA on TT. Then we had to use climo and history to guess at the meso features. And in some ways maybe that was better. If you know how to actually use the models correctly and adjust it’s good but if you’re a weekend weather worrier who just rips and runs with a model verbatim having these details shift around on every model every run will drive you crazy. 

Great point. I definitely agree that’s true. Mesoscale features especially in a fast moving, borderline event where rate dependencies play a role arent going to be picked up across the board thanks to the differing resolutions. 

[Deck Pic]

MBY forecast final

Snow after 1 am - upper 20s

Snow tapers late morning - low 30s

2-3"

[Wetbulbs88]

8 minutes ago, psuhoffman said:

Part of that is due to models being much higher resolution then before. The differences are in these meso banding that guidance couldn’t have even seen 20 years ago. Everything would have looked smoothed like the JMA on TT. Then we had to use climo and history to guess at the meso features. And in some ways maybe that was better. If you know how to actually use the models correctly and adjust it’s good but if you’re a weekend weather worrier who just rips and runs with a model verbatim having these details shift around on every model every run will drive you crazy. 

Excellent point. Bob Chill mentioned this earlier but I’d be surprised if southern MD does better than me. It’s just climo. 

[Rvarookie]

I’m expecting to fail and if so least I have some wings, drinks, and Super Bowl to appreciate it. If I do score, then I’ll just drink even more. It’s a win win situation

[Baltimorewx]

Now that all 12z data is in, this seems like a fairly uniform 2-4” event to me, mainly on colder surfaces obviously. Perhaps someone lucks out and picks up warning criteria of 5 or 6” but I’d bet most people fall in that 2-4” range. I think the NWS jumped the gun a little on the warnings. Hey it’s something but unfortunately we still can’t seem to get the late trends to be favorable with storms right now. 

[jayyy]

8 minutes ago, Wetbulbs88 said:

Excellent point. Bob Chill mentioned this earlier but I’d be surprised if southern MD does better than me. It’s just climo. 

100%. I actually think my brother down in Howard county will do better than me up here in Carroll county, but I don’t see places in SoMD doing better in a marginal event. Guess you never know though. 

[psuhoffman]

26 minutes ago, Bob Chill said:

Just my weenie opinion but models cutting off "decent" qpf along or near 95 will prob be wrong. It's a compact storm but these usually end up more broad to the NW with qpf distribution. I can't think of any shortwave with a defined lp center on the current track that didnt expand in the closing minutes. You can prob rattle off 6 that didn't tho cuz you b past event rainman and stuff. There a few of you northern folks who are literally a hard drive. Must be the cleaner air up there or something

 

19 minutes ago, Bob Chill said:

The 13-15 stretch had some nw busts/cutoffs but that's always a risk when there's full on static eletricity storm dry arctic air to push out of the way. There's nothing really impeding a nw expansion other than it being a single stream compact storm. 

Hope you don’t mind but moved this over from the other thread since it’s more pertinent here. Agree with both above. There are no comp examples I can think of where a wave like this sunk southeast at the last minute. The examples you cited like March 2014 and Feb 2015 had true Arctic air pressing and a TPV centered further east really compressing the flow. I can’t think of a single example of an amplifying wave with nothing but southwest flow and no vortex to the northeast that didn’t trend north some at the last minute.  But I guess if you pay attention long enough there is a first for everything. 

But that’s why I was kind of surprised to see guidance shift a little southeast the last 2 runs but there is still time.  I do expect it to juice up some later today and tonight. 

[87storms]

Just now, Baltimorewx said:

Now that all 12z data is in, this seems like a fairly uniform 2-4” event to me, mainly on colder surfaces obviously. Perhaps someone lucks out and picks up warning criteria of 5 or 6” but I’d bet most people fall in that 2-4” range. I think the NWS jumped the gun a little on the warnings. Hey it’s something but unfortunately we still can’t seem to get the late trends to be favorable with storms right now. 

Agreed with the 2-4” based on qpf/temps, but this also seems like one of those systems that could tick nw a bit depending on how much it can phase with that northern piece.

[jayyy]

7 minutes ago, Baltimorewx said:

Now that all 12z data is in, this seems like a fairly uniform 2-4” event to me, mainly on colder surfaces obviously. Perhaps someone lucks out and picks up warning criteria of 5 or 6” but I’d bet most people fall in that 2-4” range. I think the NWS jumped the gun a little on the warnings. Hey it’s something but unfortunately we still can’t seem to get the late trends to be favorable with storms right now. 

Or... wait for it... a team of meteorologists who work for NWS didn’t hug trends on kuchera run snow maps and used a combination of knowledge of the setup, the overall track, and all of the other factors we discuss daily in here to make an informed decision on a forecast that’s meant to inform the public of what could be coming. If they downplayed this as a 1-3 event and we saw 6+“ in 6-10 hours, it would catch a ton of people off guard and cause harm. Let’s remember the actual point of warnings issued by LWX or any other NWS office. 

[Baltimorewx]

2 minutes ago, jayyy said:

Or... wait for it... a team of meteorologists who work for NWS didn’t hug trends on kuchera run snow maps and used a combination of knowledge of the setup, the overall track, and all of the other factors we discuss daily in here to make an informed decision on a forecast that’s meant to inform the public of what could be coming. If they downplayed this as a 1-3 event and we saw 6+“ in 6 hours, it would catch a ton of people off guard and cause harm. Let’s remember the actual point of warnings issued by LWX or any other NWS office. 

Advisories serve a purpose as well. Just think they potentially could have waited a little longer to decide whether to go with advisory’s or warnings. Especially being a Sunday morning event and not rush hour traffic during the week stuff.  Nobody ever wants to downgrade either, and that may be coming later today or as the storm starts  for some. 

[Deck Pic]

[Bob Chill]

7 minutes ago, Baltimorewx said:

Now that all 12z data is in, this seems like a fairly uniform 2-4” event to me, mainly on colder surfaces obviously. Perhaps someone lucks out and picks up warning criteria of 5 or 6” but I’d bet most people fall in that 2-4” range. I think the NWS jumped the gun a little on the warnings. Hey it’s something but unfortunately we still can’t seem to get the late trends to be favorable with storms right now. 

With a defined lp storm and meso banding to the NW, I disagree they jumped the gun at all. I got 6" total last storm but impact on roads/travel was pretty minimal because it was stretched over 3 full days. 4" in 4 hours can paralyze our area. Totals and impact are not one in the same. Hoisting a warning for the public is very warranted even if criteria doesnt verify imo

[Awilson]

Nbc4 updated snowman as of 12 min ago 

[jayyy]

What señor chill said. 

[Baltimorewx]

1 minute ago, Bob Chill said:

With a defined lp storm and meso banding to the NW, I disagree they jumped the gun at all. I got 6" total last storm but impact on roads/travel was pretty minimal because it was stretched over 3 full days. 4" in 4 hours can paralyze our area. Totals and impact are not one in the same. Hoisting a warning for the public is very warranted even if criteria doesnt verify imo

If it wasn’t such a marginal temperature event I’d be more inclined to agree. In the end, we’ll see

[jayyy]

Just now, Awilson said:

Nbc4 updated snowman as of 12 min ago 

Actually one of the more reasonable maps I’ve seen. This is a Classic 2-5” type event with lollipop 6-7” for our area. Buckle up and enjoy my friends 

[mappy]

I think 3-6 is a pretty good call across the area for most. Obviously there’s going to be some who jackpot and others who don’t see much in the end. You all know your climo and should be limiting expectations to that. 

[BTRWx's Thanks Giving]

For what it's worth, Bob Ryan posted on Facebook that he doesn't like recent trends for D.C.

[HighStakes]

3 minutes ago, Baltimorewx said:

If it wasn’t such a marginal temperature event I’d be more inclined to agree. In the end, we’ll see

It's not really a marginal event NW of 95.

[BTRWx's Thanks Giving]

1 minute ago, HighStakes said:

It's not really a marginal event NW of 95.

It might be with qpf.

[Baltimorewx]

1 minute ago, HighStakes said:

It's not really a marginal event NW of 95.

What is this notion that it’s so much colder north and west of 95? Even the NAM has pretty much the entire area at 33 for the duration of the event 

[WinterWxLuvr]

17 minutes ago, psuhoffman said:

 

Hope you don’t mind but moved this over from the other thread since it’s more pertinent here. Agree with both above. There are no comp examples I can think of where a wave like this sunk southeast at the last minute. The examples you cited like March 2014 and Feb 2015 had true Arctic air pressing and a TPV centered further east really compressing the flow. I can’t think of a single example of an amplifying wave with nothing but southwest flow and no vortex to the northeast that didn’t trend north some at the last minute.  But I guess if you pay attention long enough there is a first for everything. 

But that’s why I was kind of surprised to see guidance shift a little southeast the last 2 runs but there is still time.  I do expect it to juice up some later today and tonight. 

I think it’s just an overall weaker system than what we were looking about 36 hours ago

[DDweatherman]

By no means am I expecting it, but this is usually when the NAM comes in more amped and weenies out. 
 

 

[dukeblue219]

1 minute ago, Baltimorewx said:

What is this notion that it’s so much colder north and west of 95? Even the NAM has pretty much the entire area at 33 for the duration of the event 

Because it's ALWAYS 36 in downtown DC while people in Rockville are reporting 29.

[WinterWxLuvr]

2 minutes ago, Baltimorewx said:

What is this notion that it’s so much colder north and west of 95? Even the NAM has pretty much the entire area at 33 for the duration of the event 

Doesn’t have to be so much colder. A degree or two is all it takes.