March 13/14th Storm Thread (Storm Mode)

[Deck Pic]

DCA is 34-35 whole storm....not like it is that far off...it's just model output....but a good reason to be cautious

[cae]

3 minutes ago, Amped said:

Map posted in the NYC forum.  Looks crazy Wilmington to Boston

 

6 minutes ago, WeatherFeen2000 said:

Feel free to delete it!

[AlaskaETC]

DC still gets 9" on that, but that probably includes sleet, no?

[AlaskaETC]

4 minutes ago, Z-Cast said:

Little confused by this run- on EuroWX it shows through 96hr roughly 7" for Loudoun- but then at 12Z Thurs totals jump region wide to 16"+....has the evolution of the Low stalled? 

That's interesting. I think you are allowed to post EuroWX maps?

[Snowman.]

EuroWX map.. probably more accurate.

 

[krasnyoktyabr]

11 minutes ago, Buddy1987 said:

Bob, how does it look toward the 81 corrdidor/ blue ridge empire? Anything better than the horrid GFS run? 

Not Bob, so take with a grain of salt. 

That ns low is further north and the storm doesn't interact with it as far south. The snow map looks a little better and the qpf is about 0.25 higher from the maps I've seen, but it is a little warmer. Basically no change for us.

Edit: could even end up worse if there is a warm layer.

[Deck Pic]

4 minutes ago, Bob Chill said:

Matt, something doesn't compute. At 0z tues, surface is mid to upper 30's with dews in the low to mid 20s. Precip moves in and temps barely drop as dews rise. Surface winds are out of the NE. What am I missing here? Surface should cool quickly after dark with that setup. It's not like southerly winds are scouring. 

lets toss it ..988 in the same location as GFS.....I think it might be overdoing ocean influence....

[Z-Cast]

1 minute ago, AlaskaETC said:

That's interesting. I think you are allowed to post EuroWX maps?

I figured it out. It was from the previous 12Z run. Hadn't output the tonight's 0Z run into HR108 yet.

[AlaskaETC]

1 minute ago, Snowman. said:

EuroWX map.. probably more accurate.

 

Yeah, that makes a lot more sense to me.

[psuhoffman]

This euro run was dangerously close to getting going too late for our area in general. That's a problem we had been moving away from until this run. Just one run of one op but thats not a trend I want to see start. 

[NaoPos]

weaker southern stream, late developing h7 low, hence the taint.

[osfan24]

2 minutes ago, psuhoffman said:

This euro run was dangerously close to getting going too late for our area in general. That's a problem we had been moving away from until this run. Just one run of one op but thats not a trend I want to see start. 

Yep. It's basically a bit too warm and a bit too late for our area, but just north of our area, it turns into a top 10 snowstorm. Be a tiny bit colder with a little more development and those 18-24 amounts should slide toward us. Of course, they could just as easily remain where they are or slip farther north.

[Maestrobjwa]

1 minute ago, osfan24 said:

Yep. It's basically a bit too warm and a bit too late for our area, but just north of our area, it turns into a top 10 snowstorm. Be a tiny bit colder with a little more development and those 18-24 amounts should slide toward us. Of course, they could just as easily remain where they are or slip farther north.

And this is where the more painful part of this hobby of ours is...But again, I'll take 5-7" as a consolation prize. But less than 5? Complete disaster. We may be waffling all the way until Monday (but let's hope not!)

[Deck Pic]

11 minutes ago, psuhoffman said:

This euro run was dangerously close to getting going too late for our area in general. That's a problem we had been moving away from until this run. Just one run of one op but thats not a trend I want to see start. 

That's part of it. But Gridded GFS MOS is similar at surface to euro.  It may be that GFS is too cold. I'd hate to think we're sweating the air mass.  With that track and that air mass and that high pressure the setup is so unique and ideal. If the track or development screws us so be it.  But I hate to think I'm going to be like 45/24 late Monday afternoon. Part of the reason this whole thing works is the air mass gives me wiggle room when everything else goes wrong. Part of the reason this whole thing works is I am cloudy and like 37/15 at dusk and not 52 like on 3/5/13.  44/21 before the snow starts is not going to cut it for me 

[Deck Pic]

Ensembles out to 60

[Snowman.]

EPS mean went up from 12z

 

[Swiscaster]

38 minutes ago, Snowman. said:

EuroWX map.. probably more accurate.

 

This looks similar to the way the GFS trended last run.  After the GFS run, I expressed concern that snow totals to the immediate SW were dropping off and that the SW edge of the good stuff was too close for comfort.  It seemed to fall on deaf ears as everyone was celebrating verbatim output overhead without acknowledging the alarming trend that seems to happen in Miller Bs.  At first, it looks like the secondary will develop in time for us and we are solidly in the good stuff.  Then, as the event approaches, the models seem to always progress the good stuff further and further NE.  And by the time of the actual storm, we are often left with nothing in the no man's land.  This looks to be trending that same way.  Could be a PHL-NE special.

[Deck Pic]

Yes. EPS mean is better than OP in my opinion. Maybe a bit more than noise. 1.5" QPF tickling D.C. And even on SV, 10"+ Roughly on a McLean to shady grove line. Tomorrow's 12z run is probably last super useful run for ensembles. But I feel good about the mean. Supports the op. But better. 

[Roger Smith]

I expect model trends to favor stronger coastal development and more dramatic phase of upper low, it is striking how similar the 500-mb chart looks by Monday to the Florida deepening phase of the 1993 storm. The only significant difference is that in 1993 the trough was more pronounced with lower heights in the n.e. Gulf of Mexico. But the shape of the upper trough and coastal vort max look very similar. In that case, the southeast low deepened very rapidly and took over the surface circulation at the expense of anything supported by the lower Lakes upper low. Perhaps in this case we'll be seeing a more rapid development of the wave east of Georgia late Sunday into early Monday, then the feeble warm advection left over from the northern stream low will cease to be a factor as a major storm develops around one primary center near Hatteras. 

A key to this would be somewhat faster progress of the ULL on GEM guidance. The GEM is so slow with the ULL that the coastal remains independent and that's another way to get this to be all snow, but without the widespread large amounts. 

Anyway, it's great to have winter back even if it is spring. 

[Buddy1987]

Roger, thank you for your insight as usual and your expertise with big events. Just as you write this, 6Z NAM weakened the OH Valley low dramatically. Entire 81 corridor is annihilated this run between hours 66 and 72. Lets hope to a better day of model runs compared to last nights.

[AlaskaETC]

4 minutes ago, Buddy1987 said:

Roger, thank you for your insight as usual and your expertise with big events. Just as you write this, 6Z NAM weakened the OH Valley low dramatically. Entire 81 corridor is annihilated this run between hours 66 and 72. Lets hope to a better day of model runs compared to last nights.

The evolution is also hilarious. Double lows and the southern stream is much weaker

[Buddy1987]

4 minutes ago, AlaskaETC said:

The evolution is also hilarious. Double lows and the southern stream is much weaker

Very true lol. It has those two precipitation maximas, one east of MYR and one inside Hatteras. Wonky once again, however hopefully the trend today will continue to be to squash the primary was the whole point to my post. 

[Kleimax]

6z NAM keeps NS system north and doesn't phase at all until it gets to NYC

[Kleimax]

We need the NS system to come down farther south which would equal an earlier phase. 

[Wonderdog]

NAM is 6mb weaker.

[Wonderdog]

2 hours ago, Swiscaster said:

This looks similar to the way the GFS trended last run.  After the GFS run, I expressed concern that snow totals to the immediate SW were dropping off and that the SW edge of the good stuff was too close for comfort.  It seemed to fall on deaf ears as everyone was celebrating verbatim output overhead without acknowledging the alarming trend that seems to happen in Miller Bs.  At first, it looks like the secondary will develop in time for us and we are solidly in the good stuff.  Then, as the event approaches, the models seem to always progress the good stuff further and further NE.  And by the time of the actual storm, we are often left with nothing in the no man's land.  This looks to be trending that same way.  Could be a PHL-NE special.

With respect to Miller B's, I wonder if that is just the way they usually affect our area or if it is problem the model has.

[showmethesnow]

I know some begin to dismiss the ensembles at this point but I still find them useful especially in regards to whether they support the op run or whether they are throwing up a red flag that it may be off.

Looking over the EPS and it does support the latest op run for the most part. The northern part of the trough diving down through the lakes with its associated energy is a touch quicker, stronger and dives a little deeper. We are also seeing a muting of our shortwave riding up the coast associated with out storm. These slight changes at 500mb are somewhat impacting the evolution of the storm and this can be seen somewhat on the surface. The low in the Midwest is a little stronger, holds on longer and is shifted to the east a touch. The impacts from this Midwest low can be seen on our storm coming up the coast. The storm does not ramp up as fast to our south and we now see it being tugged a touch westward on the northern portion of its track as it comes under stronger influence from the Midwest low. 

Just seeing the impacts from these subtle changes at 500mb in regards to the common sense weather (rain/snow line, intensity, qpf, etc...) for our region with this storm clearly shows the fine line we are riding with the interaction between the northern stream and our storm. At this point in time and with the current setup I have to believe we need to root for a solution that has as little northern stream influence as possible as the storm moves up into our region. Barring somewhat major shifts in the 500's, hoping for a NS phase in time to benefit our region is probably a lost cause.

 

[Wonderdog]

Heavy snow on 6z at midnight on Monday. LP is just east of Hatteras and not a little inland as shown on 0z run.

[Wonderdog]

994 LP just east of Chesapeake with continuing heavy snow at hour 78.

[showmethesnow]

After looking over the 500's and the surface on the EPS, where in my mind they degraded a touch, I was somewhat surprised to see the Snowfall means are very similar to the 12z and may have in fact improved just a touch when considering the overall region. The control run, which for the most part is the op run at lower resolution, is a beast with abroad cone of heavy snow from DC and northeastward. We see 16+ though DC with increasing amounts NE. Just NE of Baltimore is clocking in with close to 2 feet of snow. Looking at the individual members the general theme among them is the heaviest snow will be in the favored climo region in MD, North and west of the cities. There are a few absolute maulings in the mix with 2+ feet to almost 3 feet.