Mid to Long Term Discussion 2018

[Batman]

It will be interesting to see how high pressure positions itself after the storm exits the NE and how the wedge develops. Could be interesting especially north and east of me. Also, it is looking like we MAY not have a complete pattern flip after this week. Relaxation from the extreme cold yes, but more signs showing potential below normal well into January for our part of the country.

[BullCityWx]

6z GFS was better but I wasnt impressed with the 0z euro at all. 

[Blue_Ridge_Escarpment]

5 minutes ago, Queencitywx said:

6z GFS was better but I wasnt impressed with the 0z euro at all. 

If I saw the ice accum map correctly, looked like .25-.50 of ice in CAD areas just east of blue ridge on 0Z Euro. That’s WSW criteria 

[BullCityWx]

Just now, Blue_Ridge_Escarpment said:

If I saw the ice accum map correctly, looked like .25-.50 of ice in CAD areas just east of blue ridge on 0Z Euro. That’s WSW criteria 

Temps are warmer though, bordering 32, so that would mitigate accumulations. It would be one of those ZR events where the tree tops have a bit of a glisten but surface impacts would be negligible. 

[mackerel_sky]

Think the models are going to underestimate the temps. Not wishcasting, but solid snowpack down the east coast, and it would be stale, but true arctic air and probably really low DPs

[BullCityWx]

13 minutes ago, mackerel_sky said:

Think the models are going to underestimate the temps. Not wishcasting, but solid snowpack down the east coast, and it would be stale, but true arctic air and probably really low DPs

We’re going to have it in place, I’m just worried about precip being way too light to bottom out.

[BK Rambler]

FFC is interested - from this morning's discussion:

"GFS and ECMWF models are in good agreement regarding the timing of this
frontal feature, bringing PoPs in late Sunday night and until
early Tuesday morning when the moves eastward out of the area.
With this continuing increased confidence, have increased to
categorical PoPs during the daytime on Monday. By Sunday night, a
wedge will have formed across the northeast portions of the
forecast area. Cold temperatures at the surface within the wedge
combined with warmer temperatures aloft will create the potential
for freezing rain and sleet. Wintry precipitation total will be
highly dependent on the position and strength of the wedge, so
forecast will be subject to change over the next few days."

They have already put mix of rain / freezing rain into the forecast for my area (N Metro ATL) for Sunday night / Monday AM

[mackerel_sky]

6 minutes ago, Queencitywx said:

We’re going to have it in place, I’m just worried about precip being way too light to bottom out.

Somehow most winter events arrive earlier than models show. It usually more noticeable when we are waiting on cold air and precip comes aloe sooner, before the cold arrives. Should be fun to track , at about 4 days out

[FallsLake]

GFS says the January thaw starts at mid month. Looking at the indices, the PNA looks to stay positive(good), AO has a huge spread but I guess it averages negative (??good), NAO does what it always does and stays positive (bad), but the biggest difference is the EPO looks to go positive (bad). We've seen winters where the LR models show warmth just to get the warmth knocked back as we get closer. But I would say a thaw/relaxation should be expected. The question then is how long does it last.

6z GFS day 16 2m anomalies:

  

[mackerel_sky]

2 minutes ago, FallsLake said:

GFS says the January thaw starts at mid month. Looking at the indices, the PNA looks to stay positive(good), AO has a huge spread but I guess it averages negative (??good), NAO does what it always does and stays positive (bad), but the biggest difference is the EPO looks to go positive (bad). We've seen winters where the LR models show warmth just to get the warmth knocked back as we get closer. But I would say a thaw/relaxation should be expected. The question then is how long does it last.

6z GFS day 16 2m anomalies:

  

Euro shows not as much torch and has - EPO

[FallsLake]

2 minutes ago, mackerel_sky said:

Euro shows not as much torch and has - EPO

That would be great. I still think we go through some sort of relaxation. No science to why, but basically because we normally do from a historical perspective.   

[Jet Stream Rider]

Just noting that this winter we now have had a relatively rare Atlanta and vicinity snow storm, and a relatively rare Coastal Plain snow storm. Will we have another relatively rare event I wonder? Or maybe a more standard interior snow to close down that dang Wake county snow hole.

[packbacker]

GFS is 33-34F rain for a lot of area with heavy qpf.  Single digit dew points before all this starts too.  Should warm up very quick though with sliding HP.

[packbacker]

Cut off as it approaches but then opens up.  Should be some solid rain, I would hope.  Wash all this salt away.

[mackerel_sky]

6 minutes ago, packbacker said:

GFS is 33-34F rain for a lot of area with heavy qpf.  Single digit dew points before all this starts too.  Should warm up very quick though with sliding HP.

Enjoy your flurries! This gonna be a big dog ice storm for N Ga and W Carolinas! You will be in the 40s by the time your half inch of rain arrives!

[griteater]

Looking like it may be tough to avoid an icy commute in NE GA into western Carolinas Monday AM.  Cold, dry airmass in place, but sfc high moving off the coast so it's in-situ damming....could end up with one of those E VA meso sfc highs if the precip locks in the cold damming.

As precip breaks out overnight Sunday, Euro has NE GA with temps of 29-30 and dewpoints in single digits and low teens.

Move to Monday commute and Euro has SC upstate in the upper 20's with dewpoints in negative single digits to low teens.

So, hard to buy a quick warm up if the precip gets in there and locks it down.

[FallsLake]

3 minutes ago, griteater said:

Looking like it may be tough to avoid an icy commute in NE GA into western Carolinas Monday AM.  Cold, dry airmass in place, but sfc high moving off the coast so it's in-situ damming....could end up with one of those E VA meso sfc highs if the precip locks in the cold damming.

As precip breaks out overnight Sunday, Euro has NE GA with temps of 29-30 and dewpoints in single digits and low teens.

Move to Monday commute and Euro has SC upstate in the upper 20's with dewpoints in negative single digits to low teens.

So, hard to buy a quick warm up if the precip gets in there and locks it down.

12z NAM dew points at hour 84. Hard to dismiss the possibility of a strong in-situ damming event.

 

[Cold Rain]

3 minutes ago, FallsLake said:

12z NAM dew points at hour 84. Hard to dismiss the possibility of a strong in-situ damming event.

 

Yeah, with the snow cover to the north, cold, dry air transport into the area should be efficient.  The timing of all of these features is critical, as always, but I’m sure the Cadding is underdone on the globals.  If you’re going to be stuck with insitu, this is about as good of a setup as you can hope for.  Just have to get that high to hang on a bit longer and the precip to move in a bit faster...all doable over the next few days.  Also, the track of the system is pretty good.  I’ve seen a lot worse.

[mackerel_sky]

5 minutes ago, FallsLake said:

12z NAM dew points at hour 84. Hard to dismiss the possibility of a strong in-situ damming event.

 

Great analysis by you , and grit! That's some really dry air and cold air. And it's on the NAM, it's good with temps normally, but 84 HR NAM!

[mrdaddyman]

2 minutes ago, Cold Rain said:

Yeah, with the snow cover to the north, cold, dry air transport into the area should be efficient.  The timing of all of these features is critical, as always, but I’m sure the Cadding is underdone on the globals.  If you’re going to be stuck with insitu, this is about as good of a setup as you can hope for.  Just have to get that high to hang on a bit longer and the precip to move in a bit faster...all doable over the next few days.  Also, the track of the system is pretty good.  I’ve seen a lot worse.

Running a trend loop on the GFS shows the HP inching back towards NC. I agree with the track. Think this is doable and will look better come game time.

[FallsLake]

1 minute ago, mackerel_sky said:

Great analysis by you , and grit! That's some really dry air and cold air. And it's on the NAM, it's good with temps normally, but 84 HR NAM!

But this air mass will already be in place. I think the big questions are, how fast does the precip come in and (as Grit said) can a meso high develop to our north. Big pieces to the puzzle.   

[mrdaddyman]

22 minutes ago, packbacker said:

Cut off as it approaches but then opens up.  Should be some solid rain, I would hope.  Wash all this salt away.

Where is the LP at the surface usually located if you are looking at the 500MB Vort map such as above? Been wondering where it translates to at the surface.

[Cold Rain]

7 minutes ago, mrdaddyman said:

Where is the LP at the surface usually located if you are looking at the 500MB Vort map such as above? Been wondering where it translates to at the surface.

Looks like it might be over upstate SC, just looking at that 500mb panel.

[packbacker]

24 minutes ago, mackerel_sky said:

Enjoy your flurries! This gonna be a big dog ice storm for N Ga and W Carolinas! You will be in the 40s by the time your half inch of rain arrives!

When your power comes back on Wednesday you can let us know how great the ice storm was.  

33-34F and driving rain on Sunday night sounds fun though.  It's what we do best. 

[mrdaddyman]

2 minutes ago, Cold Rain said:

Looks like it might be over upstate SC, just looking at that 500mb panel.

Thanks CR!

[griteater]

11 minutes ago, mrdaddyman said:

Where is the LP at the surface usually located if you are looking at the 500MB Vort map such as above? Been wondering where it translates to on the surface map.

Some info here: http://www.atmo.arizona.edu/students/courselinks/spring13/atmo170a1s1/lecture_notes/ul_charts/ul_charts_pt3.html

[packbacker]

1 hour ago, mackerel_sky said:

Euro shows not as much torch and has - EPO

The -EPO on the Euro needs to go in the shop...this doesn't look like a -EPO.  This looks like spring...

[mrdaddyman]

Just now, griteater said:

Some info here: http://www.atmo.arizona.edu/students/courselinks/spring13/atmo170a1s1/lecture_notes/ul_charts/ul_charts_pt3.html

Thanks for the link Grit! I'll check it out.

[Cold Rain]

3 minutes ago, mrdaddyman said:

Thanks CR!

Here’s the surface map at that same time frame.  It looks like the main low is back under the closed upper low, but the trough itself argues for one farther east.

[Cold Rain]

Probably getting ready to redevelop on the other side of the cold dome.