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March med-long range disco thread 2

WxUSAF

By WxUSAF,
in Mid Atlantic

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psuhoffman

psuhoffman

Posted
Posted
2 hours ago, yoda said:

00z GEFS ensemble mean is a weenie run :lol:

It's nice yes but for the Sunday threat it shifted south noticeably again. It's just lagging behind the op a bit. But i always compare to previous runs. I'd like to see the south trend stop now. I don't mind seeing the bullseye hanging around in central or southern va 100 hours out. It probably adjusts north in the end like most. But another day of southwards trend like today and a 75 mile north shift at the end (about what it's been this year with early Jan and feb storms) won't help. 

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Maestrobjwa

Maestrobjwa

Posted
Posted
11 minutes ago, psuhoffman said:

It's nice yes but for the Sunday threat it shifted south noticeably again. It's just lagging behind the op a bit. But i always compare to previous runs. I'd like to see the south trend stop now. I don't mind seeing the bullseye hanging around in central or southern va 100 hours out. It probably adjusts north in the end like most. But another day of southwards trend like today and a 75 mile north shift at the end (about what it's been this year with early Jan and feb storms) won't help. 

So what elements here could cause the potential suppression the current model runs have? (Someone in the NYC mentioned the PV being too strong or something of that nature)

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psuhoffman

psuhoffman

Posted
Posted
7 minutes ago, Maestrobjwa said:

So what elements here could cause the potential suppression the current model runs have? (Someone in the NYC mentioned the PV being too strong or something of that nature)

The 50/50 low feature is just a bit too strong and or close. It doesn't allow any ridging in front of the vort for Sunday's storm. That prevents amplification. We need some ridging just not too much. It's a delicate balance. Very minor adjustments in the PV location have big changes to our ground truth. 

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PDIII

PDIII

Posted
Posted
2 hours ago, Deck Pic said:

I wish we could get this thing more amped...it's become this wimpy southern slider

Maybe today is the day we stop the bleeding and move back in to a more positive direction as the models zero in on a solution.  I am going to try and stay as optimistic as possible.

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PDIII

PDIII

Posted
Posted
2 hours ago, chris624wx said:

Yep...Norfolk, VA is the place to be for Sunday according to this run. Didn't they already have a blizzard warning earlier this year? Ugh

yeah.  And I am thinking it verified also.  Just 75 miles north I was driving on route 50 between OCMD and salisbury and it was solid white out conditions.  Some of the best snow driving of my life.  Well the second best.. the best was 2001 when I chased lake effect on Interstate 90.  

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PDIII

PDIII

Posted
Posted
1 hour ago, Maestrobjwa said:

So what elements here could cause the potential suppression the current model runs have? (Someone in the NYC mentioned the PV being too strong or something of that nature)

I dont really know anything.. but I suspect it has something to do with the fast flow in the upper levels..  I actually like the Canadian solution where a piece of energy is left back in GOM and then rides up the coast a couple of days later....

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NaoPos

NaoPos

Posted
Posted
3 minutes ago, nj2va said:

6z GFS came back north.  Generally region wide 8-12" from EZF north into MD.

Where did you get the GFS run from? I can't get it in TT or ncep. You sure it's not yesterday's 6z?

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showmethesnow

showmethesnow

Posted
Posted

Eps snowfall output for those that don't have it.

Friday Event: Trace amounts on the means have pulled a hair north to just south of DC. 1/2 inch line has shifted 25 miles south to where it now runs the length of the Mason Dixon line. One inch line has withdrawn significantly north and west into northern Pa and the mountains of western PA. The lower resolution control run matches the op run to a tee with the strip of snow running through MD, heaviest strip of 1/2 inch running roughly from Dc and eastward to the shore. Looking at individual members show that roughly 3/5 favor a non-event and the other 2/5 have a solution that favors around the MD/PA border and north with trace amounts to several inches. 

Sunday event:

Nailing this time frame is somewhat difficult because we are seeing an uptick with snowfall immediately afterwards. Haven't looked closely into why this is occurring yet but have to question whether we may be evolving into a new solution in regards to this storm. (For better or worse is anyone's guess) Maybe interaction with the energy that shows up on the op to the west/northwest trailing the southern low? So my numbers will be based on a cutoff of 12z Monday. Snowfall means still favor a southerly track of heaviest snowfall through southern Va as was shown on the 12Z. Snowfall totals have also been cut down somewhat region wide (guestimate of 1/2 inch on avg to the north to an inch on avg to the south in VA). Through the whole DC/Balt region we are now seeing a one inch mean vs the 1 1/2 inch seen on the 12z. Control run closely mirrors the op run with snowfall amounts and the max strip running on the VA/NCA border. After looking at the individual members I do believe that the ensembles are hinting at the possibility of a different solution in coming runs. Will not bother counting and parsing through it at this point but I would say that roughly half the members now show little to no event and the other half that do, favor the more southerly solution.

Post Sunday event to day 10:

Will not even bother trying to sort out what we were considering the follow up storm because the picture at this point is just too muddied with the almost continuous slight uptick with snow through this period.  So will give 10 day totals instead. The 2 inch line runs south of DC and Baltimore with the 2 1/2 inch running through the northwest suburbs. 3 inch line runs the Mason Dixon line. This is a reduction from the 12z which saw the 3 1/2 inch line just south of the cities and the 4 inch line in the NW suburbs.

Totals through 15 days:

WE have also seen a reduction through 15 days. 3 inch line runs through the cities with the 3 1/2 in the NW suburbs vs. 12Z which had the 4 inch line just south of the cities with the 5 inch line in the farther suburbs to the west.

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showmethesnow

showmethesnow

Posted
Posted

Quick glance over the last couple days of EPS runs and I am not so sure it is the press from the pv that is what is pooching are chances and driving our Sunday storm south. Looking at 500mb's what I see is the flow around the pv has fluctuated a little but nothing major and in fact has withdrawn slightly north on this last run which I would think would argue against a southern solution if the press from the pv was the main driver. So I have to believe there are other factors in play. What I have noticed is that the shortwave within the mean trough has slowly weakened thus we are seeing less dig within the trough induced by this shortwave from previous runs. I have also noticed that the the shortwave has lost its initial neutral tilt as it is entering the east and now we have a fairly significant positive tilt. To only compound the problem we have seen the mean trough itself flatten somewhat and with the last run shift it slightly to the east. I think all these things are combining together to allow no room for the shortwave to amplify to help drive the low farther north thus we are seeing a weak southerly low drive east underneath us without any northerly component that would be induced by a strengthening low.

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mitchnick

mitchnick

Posted
Posted
7 minutes ago, showmethesnow said:

Quick glance over the last couple days of EPS runs and I am not so sure it is the press from the pv that is what is pooching are chances and driving our Sunday storm south. Looking at 500mb's what I see is the flow around the pv has fluctuated a little but nothing major and in fact has withdrawn slightly north on this last run which I would think would argue against a southern solution if the press from the pv was the main driver. So I have to believe there are other factors in play. What I have noticed is that the shortwave within the mean trough has slowly weakened thus we are seeing less dig within the trough induced by this shortwave from previous runs. I have also noticed that the the shortwave has lost its initial neutral tilt as it is entering the east and now we have a fairly significant positive tilt. To only compound the problem we have seen the mean trough itself flatten somewhat and with the last run shift it slightly to the east. I think all these things are combining together to allow no room for the shortwave to amplify to help drive the low farther north thus we are seeing a weak southerly low drive east underneath us without any northerly component that would be induced by a strengthening low.

As has happened all winter,  the Pacific is the culprit imho. Comparing prior runs, last night's run shows there to be a strengthening low in the southern Gulf of Alaska which is fooking up the flow across the conus.

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aldie 22

aldie 22

Posted
Posted
11 minutes ago, showmethesnow said:

Quick glance over the last couple days of EPS runs and I am not so sure it is the press from the pv that is what is pooching are chances and driving our Sunday storm south. Looking at 500mb's what I see is the flow around the pv has fluctuated a little but nothing major and in fact has withdrawn slightly north on this last run which I would think would argue against a southern solution if the press from the pv was the main driver. So I have to believe there are other factors in play. What I have noticed is that the shortwave within the mean trough has slowly weakened thus we are seeing less dig within the trough induced by this shortwave from previous runs. I have also noticed that the the shortwave has lost its initial neutral tilt as it is entering the east and now we have a fairly significant positive tilt. To only compound the problem we have seen the mean trough itself flatten somewhat and with the last run shift it slightly to the east. I think all these things are combining together to allow no room for the shortwave to amplify to help drive the low farther north thus we are seeing a weak southerly low drive east underneath us without any northerly component that would be induced by a strengthening low.

Sounds like you're describing that so called clipper that turned into lake effect snow streamers

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mitchnick

mitchnick

Posted
Posted
10 minutes ago, mitchnick said:

As has happened all winter,  the Pacific is the culprit imho. Comparing prior runs, last night's run shows there to be a strengthening low in the southern Gulf of Alaska which is fooking up the flow across the conus.

This what I'm talking about.  Go to this link the click on the left arrow to the right of the words "Prev. Runs." You'll see a low get quite strong over last 2 runs that wasn't there 3 or 4 runs ago.

http://www.tropicaltidbits.com/analysis/models/?model=ecmwf&region=namer&pkg=z500_mslp&runtime=2017030700&fh=120

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CAPE

CAPE

Posted
Posted
32 minutes ago, showmethesnow said:

Quick glance over the last couple days of EPS runs and I am not so sure it is the press from the pv that is what is pooching are chances and driving our Sunday storm south. Looking at 500mb's what I see is the flow around the pv has fluctuated a little but nothing major and in fact has withdrawn slightly north on this last run which I would think would argue against a southern solution if the press from the pv was the main driver. So I have to believe there are other factors in play. What I have noticed is that the shortwave within the mean trough has slowly weakened thus we are seeing less dig within the trough induced by this shortwave from previous runs. I have also noticed that the the shortwave has lost its initial neutral tilt as it is entering the east and now we have a fairly significant positive tilt. To only compound the problem we have seen the mean trough itself flatten somewhat and with the last run shift it slightly to the east. I think all these things are combining together to allow no room for the shortwave to amplify to help drive the low farther north thus we are seeing a weak southerly low drive east underneath us without any northerly component that would be induced by a strengthening low.

I was looking at h5 vort on the 0z euro, and there is a piece of southern stream energy along the TX gulf coast that moves into LA. Some sort of phase with this vort, and earlier, would do the trick to amp this thing, get it more neutral, and allow it to gain some latitude.

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showmethesnow

showmethesnow

Posted
Posted
5 minutes ago, mitchnick said:

As has happened all winter,  the Pacific is the culprit imho. Comparing prior runs, last night's run shows there to be a strengthening low in the southern Gulf of Alaska which is fooking up the flow across the conus.

Anybody can just blame the PAC, I myself believe it was the person that started the first trackable event of the winter. Their negative mojo ruined the winter for us. I say we find him/her and punish them with extreme prejudice. :D

On a side note. Just started glancing over the individual members of the EPS and noticed quite a few (maybe close to half?) have little to no storm for the Sunday time frame. Though this isn't a hard and fast rule but after looking through about half of the members it seems that there may be a slight correlation between the Sunday and the Tues storms. Sunday storm and the Tuesday chances diminish. No or weak and sheared out Sunday storm and the Tuesday event increases. But we are at the point in the season where you have to question whether delayed actually means denied. So I guess we will see.

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showmethesnow

showmethesnow

Posted
Posted
2 minutes ago, C.A.P.E. said:

I was looking at h5 vort on the 0z euro, and there is a piece of southern stream energy along the TX gulf coast that moves into LA. Some sort of phasing with this vort, and earlier, would do the trick to amp this thing, get it more neutral, and allow it to gain some latitude.

After looking at the ensembles I really think we are going to see the upcoming 4/5+ day period morph into something with a different look then what we have been following the last few days so I would not be surprised if the feature you mentioned plays a part. Hopefully if we do see changes it is for the better.

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