January Medium/Long Range Discussion Part 2

[SnowGoose69]

4 hours ago, BristowWx said:

That looks more like a heat dome over North America.  Or am I looking at it wrong?  

More or less.  There are setups where blocks form blocking cold air.  As a matter fact, last winter at some point was a classic mid Canadian block that prevented an air mass from coming southward which resulted in a system being mostly rain instead of snow.

[WinterWxLuvr]

5 minutes ago, high risk said:

One issue for the icing potential is that we'll be near (over?) 60 Thursday and in the 40s during the day Friday, before dropping to just below freezing Friday night.    Icing events here are good when we've been in the icebox for a few days, and all of the surfaces get chilled pretty good.     They're usually not as dramatic/impactful/pretty when it has been warm, followed by a drop in temps just before precip arrives.    Would certainly help a bit if some of the precip arrives at night Friday as the 18z GFS shows.

It takes more than a couple of days to warm the ground in early January.  However, I think your point is valid as far as freezing rain goes.  But if it starts as snow or sleet I don't think it will have any trouble sticking.

[SnowGoose69]

3 hours ago, psuhoffman said:

It's only useless because so much else is wrong. The nao isn't the problem there but alone it can't fix everything. A -nao doesn't mean automatic cold and snow. It helps yea. So many other moving parts. There are times if we gave a -epo and +pna that we want a slightly negative nao. A raging -nao in that setup would be great for NC. There are lots of puzzle pieces that fit together differently. I also don't think it's useless because it's a step to that better look you see day 15. The first step is get the dantes ridge to lift out of the east. One that pulls north enough it's going to put pressure on the western Canada lower heights to drop into the us in response also. There will also be a tendency for heights to fall over the conus under the ridge to reach equilibrium. Then the ridge in Canada retrogrades to fill the void in western Canada and suddenly the pna ridge goes up and the trough axis is in the east. 

It starts the process of getting the forcing behind the pattern working in our favor. From there it's like dominoes falling. Heights rise over Canada. Trough pulls back  southwest of AK. Heights fall over the us. And we're back in business. But we have to go through the steps can't just skip to the snow. 

 

December 2001 is the best example I know of where a -NAO did nothing.  If the GOA low is there a -NAO generally has no effect.  93-94 and 13-14 though are good examples of how well you can do with a +NAO in the right pattern.  Its much harder in general though for a -AO to be "impactless" than a -NAO, particularly in January-March.  In November and December they sometimes can exist and you can be in a full on blowtorch.

 

[high risk]

2 minutes ago, WinterWxLuvr said:

It takes more than a couple of days to warm the ground in early January.  However, I think your point is valid as far as freezing rain goes.  But if it starts as snow or sleet I don't think it will have any trouble sticking.

      I'd agree with that, and any ZR after a changeover from SN or IP might still accumulate on trees.   I'm just thinking that in terms of major road impact, they may be a little too warm unless we end up in the 27-29 degree range.

[BristowWx]

3 minutes ago, SnowGoose69 said:

More or less.  There are setups where blocks form blocking cold air.  As a matter fact, last winter at some point was a classic mid Canadian block that prevented an air mass from coming southward which resulted in a system being mostly rain instead of snow.

Gotta laugh.  Some winters manage to capture the text worst patterns.  

[SnowGoose69]

3 minutes ago, BristowWx said:

Gotta laugh.  Some winters manage to capture the text worst patterns.  

Someone here probably can remember the date.  I want to say it was prior to the blizzard but it was relatively historic in that I'd never before seen that happen

[ers-wxman1]

32 minutes ago, high risk said:

One issue for the icing potential is that we'll be near (over?) 60 Thursday and in the 40s during the day Friday, before dropping to just below freezing Friday night.    Icing events here are good when we've been in the icebox for a few days, and all of the surfaces get chilled pretty good.     They're usually not as dramatic/impactful/pretty when it has been warm, followed by a drop in temps just before precip arrives.    Would certainly help a bit if some of the precip arrives at night Friday as the 18z GFS shows.

That is true, but leading up to the one day of warmth is several days we have had in the ice box plus snow in spots. Ground is very cold now. 

[PhineasC]

I'll give my usual meh to the ice storm idea. It'll be shorts weather leading in and then barely below freezing for a short time. I'm not impressed for anyone near I-95 or the cities. Maybe out in the western areas.

[psuhoffman]

35 minutes ago, SnowGoose69 said:

Someone here probably can remember the date.  I want to say it was prior to the blizzard but it was relatively historic in that I'd never before seen that happen

There was a storm about a week before or maybe 10 days that was forced under the blocking and took a decent track but there was no cold anywhere. It was frustrating. That might be the one your talking about. 

[mitchnick]

8 minutes ago, psuhoffman said:

There was a storm about a week before or maybe 10 days that was forced under the blocking and took a decent track but there was no cold anywhere. It was frustrating. That might be the one your talking about. 

Meh, there are no numbers less than 40 in the Canadian number system,  hence cold cannot make it south of 40N. 

[yoda]

00z NAM at the very end of its run has SN/IP/FRZ Rain in C VA... 1047 high exactly where we want it placed, with 1042 contour wedged beneath us

[mitchnick]

1 minute ago, yoda said:

00z NAM at the very end of its run has SN/IP/FRZ Rain in C VA... 1047 high exactly where we want it placed, with 1042 contour wedged beneath us

Just looking at that. Cold surface. 

http://www.tropicaltidbits.com/analysis/models/?model=namconus&region=neus&pkg=T2m&runtime=2017011100&fh=84&xpos=6&ypos=45

[mitchnick]

Just checked the sounding on the NAM imby (because I'm desperate! ), and it looks like it would fall as snow after initial period of sleet.  Dry air would clearly drop temps once precip started.

CAVEAT: I AM A PATHETIC WEENIE. DO NOT READ THIS POST.

[BristowWx]

Just now, mitchnick said:

Just checked the sounding on the NAM imby (because I'm desperate! ), and it looks like it would fall as snow after initial period of sleet.  Dry air would clearly drop temps once precip started.

CAVEAT: I AM A PATHETIC WEENIE. DO NOT READ THIS POST.

This is an outstanding post.  Thank you sir.  

[mitchnick]

Here's what I'm talking about wrt the dry air dropping temps very soon after the onset of precip. Per text sounding, max temp is +.8c at 1851 meters above ground while rh is 16.3%.

 

[Ji]

this is great and all but the precip is so spotty on all the models....

[Bob Chill]

36 minutes ago, Ji said:

this is great and all but the precip is so spotty on all the models....

Gfs stepped it up to .25 or more for most of us by 18z sat. #trending 

[yoda]

5 minutes ago, Bob Chill said:

Gfs stepped it up to .25 or more for most of us by 18z sat. #trending 

QPF all frozen?

[Bob Chill]

2 hours ago, yoda said:

QPF all frozen?

The trend continues. Euro drops 1.5-2.5" of snow through 18z sat and light ice after. Midlevels good through 18z sat and surface below 32 for most through 6z sun.  Lol. 

[ravensrule]

1 minute ago, Bob Chill said:

The trend continues. Euro drops 1.5-2.5" of snow through 18z sat and light ice after. Midlevels good through 18z sat and surface below 32 for most through 6z sun.  Lol. 

Nice. Thanks for the info Bob.

[Ji]

The trend continues. Euro drops 1.5-2.5" of snow through 18z sat and light ice after. Midlevels good through 18z sat and surface below 32 for most through 6z sun.  Lol. 

Best snow run of the winter!

Sent from my SM-G930V using Tapatalk

[showmethesnow]

00Z EPS snowfall mean has improved once again for the week end time period. Puts the whole of MD, except the southern eastern shore, into the half inch category. Northern portions of counties bordering the MD/PA line are now sitting within the 1' inch except for NE MD, the snow capital, where the 1 inch line juts down. Total precip through the weekend period sits at roughly .25 for the whole metro region. 

[nj2va]

The Euro is a pretty significant event out in western MD with an 1" of QPF with temps below freezing the whole time - mixed bag of snow, sleet, and freezing rain.

[snowdude]

CMC and GFS for this weekend. Some of this will likely be sleet/freezing rain. Gotta watch that chance.

Are we allowed to post EURO maps?

[showmethesnow]

Talking at range, a day or two centered around day 13, but in my opinion at this time the GEFS and the EPS are both strongly signaling a somewhat significant low somewhere in the eastern portion of the CONUS and have been for several runs now. As far as track, temps, snow, no snow etc... no idea. Those are facts that would come into better clarity the next week or so. That is if the models even hold onto this signal over subsequent runs. 

00Z EPS mean shows a strong low in the lakes earlier in the period with a transfer of a low off of OC later in the period. Casually glancing over the individual ensembles show a different story though. The solutions being thrown out are varied but the two major camps seem to be a major low in the lakes earlier in the period or a fairly strong coastal low later in the period. And again there are many solutions being thrown out but most of the members agree on a fairly strong if not significant low from the Midwest to off the coast. I will mention that the trough placement and axis favors a more westerly solution.

Like the EPS the 00Z GEFS members also have varied solutions with the two major camps being a strong Great Lakes low or a strong southern low running up the coast. The 500's though support the solution of a southern storm running up the coast.

Not to be left out the 00Z CMS also supports the southern low with low mslp mean anomalies showing a low in the gulf running up the Eastern seaboard. The 500's support this solution as well. 

It will be interesting to see if the models hold onto this and if they do how they evolve.

[showmethesnow]

10 minutes ago, snowdude said:

CMC and GFS for this weekend. Some of this will likely be sleet/freezing rain. Gotta watch that chance.

Are we allowed to post EURO maps?

 

 

From free sites and their limited maps, yes. From the pay sites, not so much.

[showmethesnow]

Noticeable shift south with the boundary for this weekend on the 06Z GFS. Can be seen by looking at the snowfall maps that have shifted everything south 25-50 miles.

[CAPE]

17 minutes ago, showmethesnow said:

Noticeable shift south with the boundary for this weekend on the 06Z GFS. Can be seen by looking at the snowfall maps that have shifted everything south 25-50 miles.

Not surprised. I posted yesterday that this had the look of something sneaky with the cold high pressing down and a stalled front to the south with waves moving along it. Its trending towards a light snow to ice event especially the northern part of MD and N VA. Euro has been hinting at this for a few runs.

[psuhoffman]

At least things haven't gone to a raging dumpster fire. This weekend event has remained relevant against the odds given the overlying h5 pattern. Then by the time we get to next week we may see some potential on the horizon with enough clarity to start tracking. At the least the pattern is moving towards workable out at range. 

[CAPE]

35 minutes ago, showmethesnow said:

Talking at range, a day or two centered around day 13, but in my opinion at this time the GEFS and the EPS are both strongly signaling a somewhat significant low somewhere in the eastern portion of the CONUS and have been for several runs now. As far as track, temps, snow, no snow etc... no idea. Those are facts that would come into better clarity the next week or so. That is if the models even hold onto this signal over subsequent runs. 

00Z EPS mean shows a strong low in the lakes earlier in the period with a transfer of a low off of OC later in the period. Casually glancing over the individual ensembles show a different story though. The solutions being thrown out are varied but the two major camps seem to be a major low in the lakes earlier in the period or a fairly strong coastal low later in the period. And again there are many solutions being thrown out but most of the members agree on a fairly strong if not significant low from the Midwest to off the coast. I will mention that the trough placement and axis favors a more westerly solution.

Like the EPS the 00Z GEFS members also have varied solutions with the two major camps being a strong Great Lakes low or a strong southern low running up the coast. The 500's though support the solution of a southern storm running up the coast.

Not to be left out the 00Z CMS also supports the southern low with low mslp mean anomalies showing a low in the gulf running up the Eastern seaboard. The 500's support this solution as well. 

It will be interesting to see if the models hold onto this and if they do how they evolve.

The day 13 deal looks like it could be something Miller B-ish, but at least for now per the EPS, it would be difficult to get enough cold in here until after that potential storm. Certainly worth watching for trends, but that likely would be a more western track. Probably a few days too soon in the pattern progression.