Jan 16/17 light snow event.

[Ji]

I'll never forget when the Wednesday jma first showed the Saturday Feb 11 2006 storm. Took euro 3 times to catch on

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[Bob Chill]

4 minutes ago, HighStakes said:

Definitely not over yet. Everyone is going to see some snow regardless of the coastal. At this point 2-3 inches is more likely than a dusting to 1. Too bad that's not good enough for some but I'll take it.

Thats one of the problems with getting glimpses at a max scenario. Folks will set the bar right there and ignore that it's the least likely outcome. Personally, I feel pretty good that a max scenario exists and it's much higher than the most likely 1-3. Beats the S out of 1-3 being a max scenario

[RedSky]

28 minutes ago, Ji said:

Anytime we are at a crossroads and need that one final push...we go 3 step backwards

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We are like the New Orleans Saints of weather

 

[Thanatos_I_Am]

Members still loading, but the EPS looks like a significant cut in precip. Yikes.

 

ETA: Cut it right in half. Not a great run for trend’s sake.

[Cobalt]

1 minute ago, Thanatos_I_Am said:

Members still loading, but the EPS looks like a significant cut in precip. Yikes.

Yup. Mean for DC is 1.5"-2" as opposed to the 3-4" mean it had before. Cut down on the big (6"+) members completely, with only 1 giving DCA 6" . Good thing is, every member gives us snow, so it seems like accumulating snow is somewhat locked in. Still not good Euro/EPS runs

[Jebman]

We still have a little time to will in more qpf.

[attml]

I like the look of this!

[arlwx]

The latest from LWX:

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

A clipper system is expected to cross the Appalachians Tue
afternoon. Light snow is expected to develop along the trailing
front Tue morning and slowly spread ewd but any precip should
remain confined west of the I-81 through 00Z Wed.

Heights will then begin to fall rapidly Tue night in response
to approaching mid-upper level trof. As heights fall and
forcing for upward vertical motion increases, expect snow to
spread ewd reaching the I-95 corridor by 12Z Wed. There
continues to be some differences with the strength and timing
of the upper level system with the Canadian and ECMWF slower
and stronger indicating a closed low and the GFS faster and
much weaker showing an open trof. As a result, the ECMWF and its
ensemble mean show higher QPF generally 0.1 to 0.2 inches while
the GFS shows 0.1 inches or less. With the very cold air mass in
place, expect SLRs to be higher than climatology in the order
of 15 to 1 with snow totals in the 1-2 inch range likely with
isold higher totals in the south and over the mtns closer to the
track of h5 closed low and in the better moisture. Snow will
begin to taper off quickly Wed afternoon with most of the
measureable precip gone by 00Z Thu. Advisories will probably be
needed for areas west of the Blue Ridge either later today or
tonight and Tue or Tue night for areas east of the Blue Ridge.

 

[showmethesnow]

First the bad news. The 06Z 12 NAM has backed off on snowfall through the DC/Balt corridor where we are now seeing .1-.5 totals.

The good news? I think we are seeing this back off on precip because we are seeing the NAM making a move towards closing off the 500's and having more coastal interaction as we are now seeing a pickup of precip into the eastern shore from the offshore low. Now going out to 48 hour, which is the extreme range of some usefulness with the NAM, we are seeing what we need to see for upside potential. We are seeing better dig and a sharper trough dropping down into the mid-west. At this point that is all I care to see and anything beyond that on the NAM is not worth squat in my mind.

 

[showmethesnow]

06Z GFS now has picked up on snowfall where we are now seeing general 2 inch totals (Kuchera) through the DC/Balt corridor. All the snow is coming from the frontal passage as we are seeing no coastal interaction. We are also seeing a little better dig and slightly better trough axis tilt. Still doesn't seem to like the idea of closing off the 500's. 

eta: We are also seeing a slight uptick with snow on the GEFS.

[CAPE]

4 minutes ago, showmethesnow said:

06Z GFS now has picked up on snowfall where we are now seeing general 2 inch totals (Kuchera) through the DC/Balt corridor. All the snow is coming from the frontal passage as we are seeing no coastal interaction. We are also seeing a little better dig and slightly better trough axis tilt. Still doesn't seem to like the idea of closing off the 500's. 

eta: We are also seeing a slight uptick with snow on the GEFS.

The GFS idea seems the most likely outcome to me given the progressive set up. Without a nearly perfect evolution at h5, which seems unlikely, I just dont see the coastal getting going in time- as much as I would love the CMC to be right lol, I really dont think it is. Given that the snow will likely come with the front, this should favor places further NW. There may be a "no mans land" setting up around or east of I-95, as the frontal band weakens while the coastal tries to get going offshore. If that plays out I dont expect much at all imby, and a general 1/2 - 2" looks reasonable at this point for places that maximize frontal band, again favoring the northern and western burbs. You are in a good spot. 

[wkd]

6z  ggem still has closed low though slightly further east. Looks like around 1cm total precip for dc.

[mitchnick]

6z Canadian is still a decent hit. Another longer event. It starts at 54 hours,  which is the link below.  Just move it up in time.  Don't know how it compares to the 0z run because of measurements. 

http://meteocentre.com/numerical-weather-prediction/map-explorer.php?lang=en&map=na&run=06&mod=gemglb&stn=PNMPR&comp=1&run2=06&mod2=gemglb&stn2=PNMPR&hh2=048&fixhh=1&stn2_type=prog&mode=latest&yyyy=latest&mm=latest&dd=latest&hh=054

[CAPE]

1 minute ago, mitchnick said:

6z Canadian is still a decent hit. Another longer event. It starts at 60 hours,  which is the link below.  Just move it up in time.  Don't know how it compares to the 0z run because of measurements. 

http://meteocentre.com/numerical-weather-prediction/map-explorer.php?lang=en&map=na&run=06&mod=gemglb&stn=PNMPR&comp=1&run2=06&mod2=gemglb&stn2=PNMPR&hh2=048&fixhh=1&stn2_type=prog&mode=latest&yyyy=latest&mm=latest&dd=latest&hh=054

I am huggin' it lol. Just not believing it much right now.

[showmethesnow]

6 minutes ago, C.A.P.E. said:

The GFS idea seems the most likely outcome to me given the progressive set up. Without a nearly perfect evolution at h5, which seems unlikely, I just dont see the coastal getting going in time- as much as I would love the CMC to be right lol, I really dont think it is. Given that the snow will likely come with the front, this should favor places further NW. There may be a "no mans land" setting up around or east of I-95, as the frontal band weakens while the coastal tries to get going offshore. If that plays out I dont expect much at all imby, and a general 1/2 - 2" looks reasonable at this point for places that maximize frontal band, again favoring the northern and western burbs. You are in a good spot. 

Haven't really liked the possibilities for awhile now myself. But when I continue to see some models throw out attempts and/or closing off the 500's it does give me some hesitation. But it is hard to bet against the GFS at this time.

[Ji]

40 minutes ago, showmethesnow said:

First the bad news. The 06Z 12 NAM has backed off on snowfall through the DC/Balt corridor where we are now seeing .1-.5 totals.

The good news? I think we are seeing this back off on precip because we are seeing the NAM making a move towards closing off the 500's and having more coastal interaction as we are now seeing a pickup of precip into the eastern shore from the offshore low. Now going out to 48 hour, which is the extreme range of some usefulness with the NAM, we are seeing what we need to see for upside potential. We are seeing better dig and a sharper trough dropping down into the mid-west. At this point that is all I care to see and anything beyond that on the NAM is not worth squat in my mind.

 

i dont see any indication of the NAM moving to closed low. This is a long way from a closed low 

[psuhoffman]

Shame that at the moment the euro and EPS are a useless mess. And I'm not saying we know the end result but no matter what happens the euro has been useless because in the last 6 runs it's had 3 amplified cutoff solutions and 3 progressive solutions. That makes it useless since it bounces around between different extremes and camps. I'm truly astounded with how bad it's been for such a long stretch. Hopefully it's just this pattern and not a permanent problem because having one of the two flagship pieces of guidance useless to us really will hurt forecasting. We've essentially lost one of the two major data points used to judge and determine trends each model run. I don't know how anyone can take it seriously given it's track record lately but without it all we really have is the gfs/gefs (and the gefs has a group think issue) and a bunch of b level guidance. (Yea I know ukmet scores and all but I agree with JI and others that when it comes to east coast storms it has a tendency to swing wildly from over amped to progressive and doesn't have enough consistency to be reliable). 

[psuhoffman]

3 minutes ago, Ji said:

i dont see any indication of the NAM moving to closed low. This is a long way from a closed low 

It's closer then it was. Trend. Your both right. He was saying it moved closer and your saying it isn't there. Lol

[Joshfsu123]

Yep, 06z GFS looks improved somewhat for the DC area... when compared to previous runs. Hope it continues at 12z.

[showmethesnow]

Just now, Ji said:

i dont see any indication of the NAM moving to closed low. This is a long way from a closed low 

When I compare it to the 00Z run I think it did make a move towards closing off the 500's. But I guess it is a matter of opinion.

[CAPE]

2 minutes ago, psuhoffman said:

Shame that at the moment the euro and EPS are a useless mess. And I'm not saying we know the end result but no matter what happens the euro has been useless because in the last 6 runs it's had 3 amplified cutoff solutions and 3 progressive solutions. That makes it useless since it bounces around between different extremes and camps. I'm truly astounded with how bad it's been for such a long stretch. Hopefully it's just this pattern and not a permanent problem because having one of the two flagship pieces of guidance useless to us really will hurt forecasting. We've essentially lost one of the two major data points used to judge and determine trends each model run. I don't know how anyone can take it seriously given it's track record lately but without it all we really have is the gfs/gefs (and the gefs has a group think issue) and a bunch of b level guidance. (Yea I know ukmet scores and all but I agree with JI and others that when it comes to east coast storms it has a tendency to swing wildly from over amped to progressive and doesn't have enough consistency to be reliable). 

Like its formerly more skilled, but slumping cousin, lol

But yeah it is quite remarkable how mediocre the Euro has become lately, at least for our neck of the woods.

[psuhoffman]

7 minutes ago, C.A.P.E. said:

Like its formerly more skilled, but slumping cousin, lol

But yeah it is quite remarkable how mediocre the Euro has become lately, at least for our neck of the woods.

Some will keep defending it with hemispheric h5 verification scores. I'm aware. But there is a huge difference between getting the general location of h5 height anomalies correct on a global scale and accurately depicting the specific location and strength of a low pressure system along the east coast. 

Every single fart in the wind that's come along in the last month the euro has at some point in the medium range gone off on a tangent with some rediculous over amplified solution only to flip back to a progressive on. That's as much a fact as the h5 verification. So I guess if we're looking at general pattern trends the data says it's still with getting weight but if I'm trying to decide how strong a medium range system is likely to be when affecting our weather specifically it's unreliable and useless. 

[mitchnick]

1 minute ago, psuhoffman said:

Some will keep defending it with hemispheric h5 verification scores. I'm aware. But there is a huge difference between getting the general location of h5 height anomalies correct on a global scale and accurately depicting the specific location and strength of a low pressure system along the east coast. 

Every single fart in the wind that's come along in the last month the euro has at some point in the medium range gone off on a tangent with some rediculous over amplified solution only to flip back to a progressive on. That's as much a fact as the h5 verification. So I guess if we're looking at general pattern trends the data says it's still with getting weight but if I'm trying to decide how strong a medium range system is likely to be when affecting our weather specifically it's unreliable and useless. 

Yes, but you can still swear by it on sunny days.

[psuhoffman]

16 minutes ago, showmethesnow said:

When I compare it to the 00Z run I think it did make a move towards closing off the 500's. But I guess it is a matter of opinion.

It definitely did. But it's still too positively tilted and doesn't quite pull it off. My guess is JI was just comparing it to the runs that did close off not comparing it to its previous runs.  We don't need it to close off completely to get a decent event either. If it slows a bit more and goes more neutral sooner such that the front doesn't clear us before the trough catches up we could get a nice increase in qpf. The trough is digging enough there to get the southwest flow across the boundary. That's one key to better lift. But the other is having the front not clear our area before the increased vorticity from the trough swings through. Other then a few good runs things aren't looking synced up. The front clears east before we can get any help from the dynamics associated with the trough. If we want a real win and not another meh event we need those 2 things to sync up. 

[psuhoffman]

8 minutes ago, mitchnick said:

Yes, but you can still swear by it on sunny days.

Considering that about 80% of the conus is not precipitating at any given moment I would hope it could still predict where storms wont be with some skill. Lol

[mappy]

12 pages in 21 hours for a light event really showcases how desperate some are for snow. 

[showmethesnow]

5 minutes ago, psuhoffman said:

It definitely did. But it's still too positively tilted and doesn't quite pull it off. My guess is JI was just comparing it to the runs that did close off not comparing it to its previous runs.  We don't need it to close off completely to get a decent event either. If it slows a bit more and goes more neutral sooner such that the front doesn't clear us before the trough catches up we could get a nice increase in qpf. The trough is digging enough there to get the southwest flow across the boundary. That's one key to better lift. But the other is having the front not clear our area before the increased vorticity from the trough swings through. Other then a few good runs things aren't looking synced up. The front clears east before we can get any help from the dynamics associated with the trough. If we want a real win and not another meh event we need those 2 things to sync up. 

That is another point that gives me some hesitation besides the back and forth on some of the models with closing off the 500's. We have seen some play in regards to the axis tilt as well where we have had solutions pulling that trough through with a neutral tilt and on a occasion going negative as well. I am not really high on pulling off a long shot here but have some hopes we can at least get some enhancement. I'll keep following either way though.

[Bob Chill]

10 minutes ago, mappy said:

12 pages in 21 hours for a light event really showcases how desperate some are for snow. 

That's one take. Or is shows that this specific event has intricate unresolved details that can swing the outcome and we enjoy discussing winter wx that will impact much of the region either way. 

[mitchnick]

Slowing down the frontal passage will solve 80% of our problems imho. That's the basis for the Canadian and the JMA.  That's how the decent runs of the Euro did it. We can have a beatiful,  closed vort,  but if it's whizzing on by us, forget it. 

[mappy]

2 minutes ago, Bob Chill said:

That's one take. Or is shows that this specific event has intricate unresolved details that can swing the outcome and we enjoy discussing winter wx that will impact much of the region either way. 

ha, fair enough Bob.