The March 6 Storm- The (last) Great White Hope, Part II

[blizzardmeiser]

Well fellas...I have to say that the EC and EC ensembles have been rock solid with their runs of late. The EC, like the UK and CMC, do *not* jog the surface low from SEVA up into the Lower Eastern Shore like the NAM and GFS do (I didn't see the 06Z GFS)...which would result in a more prolonged period of a mix or rain in the metro region.

Moreover, talk about a model of consistency. The EC ensemble mean has DCA in the 5-7" zone, though with not one of the 50 members showing more than 9". That's pretty darn good continuity to have that kind of average without a heavier outlier.

This is not to say the EC won't trend at tad north with the 12Z run around that 12-18Z timeframe, which would result in a warmer, more easterly flow profile btwn 1000-900 mb, but it probably won't be a drastic change at this point like the NAM and GFS have shown of late.

Stick with the EC...where have we heard this before? ;-)

Temps will be an issue if this occurs

[eurojosh]

Actually, bit nauseating to look at soundings this morning. 06z GFS is only slightly better, and 06z NAM moved in the opposite direction. Around 09z Wed looks like we can make it to snow, and then, 3 hours later, both models have a surge of warm air into DCA...that never really goes away. Whether rates can make up for it I don't know, but a 32-34 surface is a huge difference from a 35-37 surface, which is where both are hovering. 

 

We need to find a cold source, or there's going to be some major disappointment east of IAD.  

 

Yeah, I don't know about this one...  Never mind GFS vs Euro, the only trend I see is that if you like at the 2m temps run after run, they're getting warmer further and further west.  This is reflected in the clown maps - compare the last 8 runs or so, and you see DC, for example, go from 14" to 0".  I know thye're just clown maps, but isn't that the point - they tend to over-exaggerate, not under-exaggerate.  With the BL temps becoming an issue, this could be quite a disappointment.

[Scraff]

FWIW--Tom Niziol on the TWC:

 

I-95 DC-Balt painted in 8-12

Slight West from there 12-18

 

Bullish, but hope that can verify...

[dsnowman]

Precip totals have not been the issue for our area (with QPFs in the 1.5 to 2 range). And once the L gets going off the coast, rates and winds (from the north / northeast) will cool us down sufficiently for snow. The models (mainly GFS/NAM) were trending north yesterday and reversed course a little last night. I am not sure why everyone is so worried about temps this morning, it was looking a lot worse last night. And the clown maps (see LWX above) are actually better than yesterday / last night for snowfall totals. Take Centreville, VA as a reference point, last night the estimate was 8-10, now it is 10-14.

[NOVAForecaster]

Clown maps are just that... Clown maps. A human with the ability to look at the models non-verbatim can figure out snow totals better than a computer can.

[BristowWx]

Precip totals have not been the issue for our area (with QPFs in the 1.5 to 2 range). And once the L gets going off the coast, rates and winds (from the north / northeast) will cool us down sufficiently for snow. The models (mainly GFS/NAM) were trending north yesterday and reversed course a little last night. I am not sure why everyone is so worried about temps this morning, it was looking a lot worse last night. And the clown maps (see LWX above) are actually better than yesterday / last night for snowfall totals. Take Centreville, VA as a reference point, last night the estimate was 8-10, now it is 10-14.

But there has to be a reason LWX hasn't pulled the hammer on a WSW for I-95. If 10-14 was really solid..even 8-10...they would I think.

[WxMan1]

Yeah, I don't know about this one... Never mind GFS vs Euro, the only trend I see is that if you like at the 2m temps run after run, they're getting warmer further and further west. This is reflected in the clown maps - compare the last 8 runs or so, and you see DC, for example, go from 14" to 0". I know thye're just clown maps, but isn't that the point - they tend to over-exaggerate, not under-exaggerate. With the BL temps becoming an issue, this could be quite a disappointment.

This could be, yes. But ask yourself if a low track from SEVA near SFQ-CPK eastward isn't a favorabld one synoptically for the DC area. That is what the non-NCEP runs and mean of all 50 EC members show. Sometimes we need to stand back and simplify the analysis synoptically speaking from a pattern-recognition standpoint, rather than digging into the dirty details of 06Z runs.

Despite any rain/mixing issues we may have btwn 12-18Z, the thermal column will crash once the low heads to and off the coast. We know from past experience that the timing of the column cooling is much faster in reality most of the time compared to what the models forecast. It's along the same lines as the models always underdoing the low level frontogenesis during events such as these, i.e. they never seem warm enough on the warm side nor cold enough on the cold side.

We may get a lot of slop, maybe mostly slop if not rain from 12-18Z, but I don't see why we can't get at least a half inch to .75 inch of liquid after the changeover to all snow...assuming the EC/EC mean/UKMet/CMC are correct with that low track farther south than the NAM and GFS.

[swimmatte]

Precip totals have not been the issue for our area (with QPFs in the 1.5 to 2 range). And once the L gets going off the coast, rates and winds (from the north / northeast) will cool us down sufficiently for snow. The models (mainly GFS/NAM) were trending north yesterday and reversed course a little last night. I am not sure why everyone is so worried about temps this morning, it was looking a lot worse last night. And the clown maps (see LWX above) are actually better than yesterday / last night for snowfall totals. Take Centreville, VA as a reference point, last night the estimate was 8-10, now it is 10-14.

But there has to be a reason LWX hasn't pulled the hammer on a WSW for I-95. If 10-14 was really solid..even 8-10...they would I think.

It's a nightmare forecast for them. That rain/snow line that runs down 95 is making it tough I'm sure.

[WxUSAF]

But there has to be a reason LWX hasn't pulled the hammer on a WSW for I-95. If 10-14 was really solid..even 8-10...they would I think.

Because there's still plenty of time with warning criteria not likely to occur until tomorrow afternoon.  I expect they'll issue with the afternoon package today for the 95 corridor at least.  

[NOVAForecaster]

I do see hope yet, as the 03Z SREF plumes for snow at IAD have actually increased since I last looked at 21Z. The mean is at 17", and the largest cluster is just above that. I don't see too much reason to be concerned about higher temps, as models almost always underdo dynamic cooling and CAD. Plus, now is when the short-range is at its best, and globals like the GFS don't have the resolution to pick out small scale features and gradients like the NAM/SREFs do. Here's the 3Z SREF plume at IAD.

 

[mitchnick]

I do see hope yet, as the 03Z SREF plumes for snow at IAD have actually increased since I last looked at 21Z. The mean is at 17", and the largest cluster is just above that. I don't see too much reason to be concerned about higher temps, as models almost always underdo dynamic cooling and CAD. Plus, now is when the short-range is at its best, and globals like the GFS don't have the resolution to pick out small scale features and gradients like the NAM/SREFs do. Here's the 3Z SREF plume at IAD.

 

 

pretty sweet

what do they show for BWI?

thanks

[hokierulz98]

Looking like elevation will be key with this one as low level temps look more and more suspect.Winchester and Harrisonburg are going to get hammered. I could see DC getting 3 - 6 inches but not anymore unless we see a SE trend today on the models today. Hey, at least you guys aren't totally screwed like us in RIC.

[NOVAForecaster]

pretty sweet

what do they show for BWI?

thanks

14" mean with a similar cluster just around there. One outlier at 3" though there unlike IAD with no members under 10"

[mitchnick]

14" mean with a similar cluster just around there. One outlier at 3" though there unlike IAD with no members under 10"

thanks

and 3" at BWI in a storm like his is always possible

just the way it is but we'll see

[hokierulz98]

Harrisonburg never gets hammered. Trust me. See February 2003.

 

 I think you'll see in the 12"-18" range out there with elevation of around 1300 feet you should do well.

[Solo2]

The sref plumes are pretty nuts for Winchester...

[Bob Chill]

thanks

and 3" at BWI in a storm like his is always possible

just the way it is but we'll see

 

 

Check these out. I wanted to get better idea of thermal structure other than a skew. These are from hr 27 (one of the sketchiest imo) from the 6z gfs. Second shade of blue is the freezing line. One the surface panel, 35 degree line runs the interstate/fall line.

 

 

Surface:

 

 

 

925:

 

 

 

850:

 

 

 

 

I don't things are as bad as some people are saying in our areas. yea, going east gets worse but this is one of the worst periods on the model. It get's better from here. 

[Symblized]

14" mean with a similar cluster just around there. One outlier at 3" though there unlike IAD with no members under 10"

 

Is that the 3z? I see that on the 9z, there are actually two outliers less than three inches, and one at three inches. There's also a crazy outlier at 25 inches. Without the highest and lowest, the mean is a foot.

 

mitch, for future reference, here's the link.

[WxUSAF]

925mb stays at or below freezing for I-95 and all points N/W for the duration on the 6z GFS. But below that is above freezing for much of the time.  I think we're back to a situation where we're rate-dependent.  Good news on that is that the precip is going to be ripping.  If the cold 850s of the Euro verify with the kind of rates we probably will have...should be predominantly snow for many.  

[Bob Chill]

Seeing it put that way, especially by you, allows me to exhale just slightly before this next set of runs.

 

It's perilous though. However, I really like the 925 temp structure as the low goes off the coast. You and I are a little more ok than dca/bwi but not nearly as good as those like in mt airy/damascus etc.

 

The thing is, we know the surface isn't going to be freezing for most if not all of the event. That's a given. It's the layer in between 850 and the surface that will make or break us irt to rain. The best thing about looking at the whole structure and not just a sounding gives you an idea of how everything is oriented. on the 6z gfs, the 925 freezing line runs i-95/fall line through all the "scarier" panels and then everything crashes back to easy snow sounding. 

 

 

edit: NINJA'D! by my favorite ex military met. 

[mitchnick]

Is that the 3z? I see that on the 9z, there are actually two outliers less than three inches, and one at three inches. There's also a crazy outlier at 25 inches. Without the highest and lowest, the mean is a foot.

 

mitch, for future reference, here's the link.

thank you

it doesn't surprise me the new SREF would be lower as the 3z was probably 0Z based not 6z or later

[mitchnick]

looking at the 6z models and the current conditions across the US off the Unysis site, I think the Canadian Maritime Low is being seen as stronger/holding on longer which is keeping the 5H vort from slowing in the wrong spot in VA

simplistic, but in the end it's just a traffic back up

hopefully NAM at 6z was just a blip and it goes back to an all snowy solution like 18z and 0z

we'll know soon enough I guess

[NOVAForecaster]

thank you

it doesn't surprise me the new SREF would be lower as the 3z was probably 0Z based not 6z or later

Yeah, 9Z came out... Still doesn't seem bad to me, mean is still 14.5" with the largest cluster still around 16". Taking away the 2 high and 2 lowest outliers still has it in a good spot with 14" still. Still, a closer call then before and as stated before me, very rate dependent.

[Bob Chill]

This clip is from hr 33. Probably the last really scary panel. It's easy to see what's going on @ 925 with the slp being so close. Verbatim, anyone east of i95'ish where the freezing line runs is in for some nervous rainy moments. West of the line isn't out of the woods either because of surface temps so obviously, the higher up and further west the happier you are. 

 

 

 

 

Sure would be nice to have the low track verify 25-50 miles south. A lot of these discussions wouldn't be happening. 

[WxUSAF]

What I think we want to see from the 12z runs is a slightly faster progression to get us in the NW quadrant of the storm earlier and associated colder 950-850mb temps.  I like hearing the Euro has our 850 temps in the -3 to -4 range.  Freezing level at 925mb is dicey.  Freezing level at 950mb (especially if the layer below is only ~1C) is very workable.  

[mitchnick]

This clip is from hr 33. Probably the last really scary panel. It's easy to see what's going on @ 925 with the slp being so close. Verbatim, anyone east of i95'ish where the freezing line runs is in for some nervous rainy moments. West of the line isn't out of the woods either because of surface temps so obviously, the higher up and further west the happier you are. 

 

 

925tmphr33.JPG

 

 

Sure would be nice to have the low track verify 25-50 miles south. A lot of these discussions wouldn't be happening. 

Bob, isn't our problem really been under 925?

models are showing 950 above freezing

personally, as much as I want the models to show all snow, it is also time to start looking at surface condition, pressures, dews, winds, and, of course temps

in any event, if we get a lot of snow, this will have been a fun storm

[stormtracker]

I have to say, I'm a lot more pessimistic than I ever was for this storm for my area.  It sucks, but we knew we could be in this situation from the beginning.   You guys out west though should be pretty stoked.  

[swimmatte]

This clip is from hr 33. Probably the last really scary panel. It's easy to see what's going on @ 925 with the slp being so close. Verbatim, anyone east of i95'ish where the freezing line runs is in for some nervous rainy moments. West of the line isn't out of the woods either because of surface temps so obviously, the higher up and further west the happier you are.

925tmphr33.JPG

Sure would be nice to have the low track verify 25-50 miles south. A lot of these discussions wouldn't be happening.

At hour 12, the LP is just south of Illinois. That's where I'll be looking for a small shift south.

Edit: Referring to the 06z GFS

[Deck Pic]

I think the 9z SREF looks better than the OP NAM, even if not by a ton

[Bob Chill]

Bob, isn't our problem really been under 925?

models are showing 950 above freezing

personally, as much as I want the models to show all snow, it is also time to start looking at surface condition, pressures, dews, winds, and, of course temps

in any event, if we get a lot of snow, this will have been a fun storm

 

Yes, between surface and 950 is a problem but it can be overcome pretty easy with rates. At least imo. I wish I had panels for 950 like 925 but I don't. It can also be overcome with a slightly better storm track. If slp tracks euroish then I can probably delete some morning posts. 

 

We're all getting accum snow until you get a good bit e-s. That's a good feeling. And if there are mixing/rain problems tomorrow then we just gotta be patient. once the backside is rippin it's accum snow and great rates.