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December 2019 Med/Long Range Disco


Bob Chill
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I would be perfectly content rolling through the winter with this general look. Though this isn't quite the full month of November (through the 27th) it is close enough to give us a good idea of what heights we saw at 500's for the month. Very sweet look IMO. 

PAC looks great with a -EO/+PNA combo over cutting a weakness in the SW. Aleutian low with troughing extending towards Hawaii. EO/PNA delivers the cold, Aleutian low delivers the energy for an active PAC jet and NS. SW weakness provides a split flow and energy injected into the southern stream. The higher heights over Mexico/Gulf help bump up that southern stream into the southern US.

Atlantic looks good as well. Central/eastern based -NAO to provide blocking. Higher heights in the central Atlantic to help offset the suppressive nature of a strong EO/PNA combo. If you also note the weakness extending between these two features (lower heights) this provides a slot for storms to travel through the 50/50 region potentially getting trapped by the -NAO. Between the PAC setup and the Atlantic we are see the troughing being forced into the eastern US. Also note the lack of lower pressures over the Arctic regions (-AO). 

I would take this look every winter and expect at worst an average winter with good odds of it being above to well above.

Nov500anoms.gif.4ce60dce4366e07837f8e697f28f960c.gif

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42 minutes ago, showmethesnow said:

I would be perfectly content rolling through the winter with this general look. Though this isn't quite the full month of November (through the 27th) it is close enough to give us a good idea of what heights we saw at 500's for the month. Very sweet look IMO. 

PAC looks great with a -EO/+PNA combo over cutting a weakness in the SW. Aleutian low with troughing extending towards Hawaii. EO/PNA delivers the cold, Aleutian low delivers the energy for an active PAC jet and NS. SW weakness provides a split flow and energy injected into the southern stream. The higher heights over Mexico/Gulf help bump up that southern stream into the southern US.

Atlantic looks good as well. Central/eastern based -NAO to provide blocking. Higher heights in the central Atlantic to help offset the suppressive nature of a strong EO/PNA combo. If you also note the weakness extending between these two features (lower heights) this provides a slot for storms to travel through the 50/50 region potentially getting trapped by the -NAO. Between the PAC setup and the Atlantic we are see the troughing being forced into the eastern US. Also note the lack of lower pressures over the Arctic regions (-AO). 

I would take this look every winter and expect at worst an average winter with good odds of it being above to well above.

Nov500anoms.gif.4ce60dce4366e07837f8e697f28f960c.gif

Nice look Showme. Pretty consistent pattern evolving next few weeks with higher heights building over the western US heading into December. A prime split-flow pattern with ample disturbances traversing the sub-tropical jet. Still a bit hesitant from what I'm seeing on the ensembles in the extended, but I wouldn't worry too much about that now. In fact, both ECM/GEFS begin to take on a better look after mid-month. Source region for cold will be solid, so even a shutout will have some benefit for later in the extended (i.e beyond mid-December). I'd take that look anytime. 

 

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9 minutes ago, MillvilleWx said:

Nice look Showme. Pretty consistent pattern evolving next few weeks with higher heights building over the western US heading into December. A prime split-flow pattern with ample disturbances traversing the sub-tropical jet. Still a bit hesitant from what I'm seeing on the ensembles in the extended, but I wouldn't worry too much about that now. In fact, both ECM/GEFS begin to take on a better look after mid-month. Source region for cold will be solid, so even a shutout will have some benefit for later in the extended (i.e beyond mid-December). I'd take that look anytime. 

 

Some winters (most) it seems that the good looks in the extended deteriorate as they near in time. This winter feels different so far where the bad looks are improving. Not a bad place to be. Kind of helps sets my state of mind while others are melting down over a day 15/16 forecast.

By the way, hope Texas is treating you well. We miss you up here.

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Just now, showmethesnow said:

Some winters (most) it seems that the good looks in the extended deteriorate as they near in time. This winter feels different so far where the bad looks are improving. Not a bad place to be. Kind of helps sets my state of mind while others are melting down over a day 15/16 forecast.

By the way, hope Texas is treating you well. We miss you up here.

I can agree with this. It certainly seems like that's the narrative lately. Hopefully for y'all sake it continues. I'm not super bullish on this winter by any means, but I do see a fair amount of chances incoming for the season. Actually bumped my snow fall forecast a bit as a result in the contest.

And my wife and I are doing okay out in Texas. We do miss home. Hope to get back to or at least closer to the ole stomping grounds in time. Really taking advantage and learning the intricacies of forecasting in the NWS. It's pretty awesome. I love what I do, but I need my snow ;)

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2 minutes ago, MillvilleWx said:

I can agree with this. It certainly seems like that's the narrative lately. Hopefully for y'all sake it continues. I'm not super bullish on this winter by any means, but I do see a fair amount of chances incoming for the season. Actually bumped my snow fall forecast a bit as a result in the contest.

And my wife and I are doing okay out in Texas. We do miss home. Hope to get back to or at least closer to the ole stomping grounds in time. Really taking advantage and learning the intricacies of forecasting in the NWS. It's pretty awesome. I love what I do, but I need my snow ;)

Started looking into things for the coming winter in later October hoping to maybe try my hand at a forecast. Got far too busy to do anything more then a preliminary look. The one thing I did notice was that there were quite a bit of conflicting signals both good and bad. But watching this November it seems that quite a few of these conflicts are tending to break our way. Been liking for the most the tendencies both on the models and in verification of actual weather. So as where I was maybe leaning an avg winter in early November I am now tending for an above one (+133%). Things I am seeing also make me believe a majority of this snow will come from our bigger storms (southern lows, coastals) vs. a bunch of nickle/dime events.

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8 minutes ago, showmethesnow said:

Started looking into things for the coming winter in later October hoping to maybe try my hand at a forecast. Got far too busy to do anything more then a preliminary look. The one thing I did notice was that there were quite a bit of conflicting signals both good and bad. But watching this November it seems that quite a few of these conflicts are tending to break our way. Been liking for the most the tendencies both on the models and in verification of actual weather. So as where I was maybe leaning an avg winter in early November I am now tending for an above one (+133%). Things I am seeing also make me believe a majority of this snow will come from our bigger storms (southern lows, coastals) vs. a bunch of nickle/dime events.

I also see this and one of the reasons I bumped my snow for BWI higher than anyone else. Just looking at recency bias would lend credence to a more active coastal track with baroclinic proxy somewhat closer to the coast. Have had a lot of lows actually positioned very well so far in fall with QPF fields in good placement. Still missing the all important cold air to sustain any winter precip, but it was still out of climo. Roll that same kind of H5 height pattern into latter December through early March, and you have to like chances to get a good storm or two. We shall see. Unlikely I'll see any snow this year unless I chase it. Looks like ice would be our biggest threat down here, but you never know. A good snow here is actually not a good precursor for back home, so I'll take my ice or cold rain lol

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Squeeze play...under 7 days now. Bubble of hp on W North America and another squeezing over the Middle East. Looks like the warming over Siberia is legit and the SPV is getting pummeled. I'll leave it to the experts to decipher what it means but it cant be bad. Beats a strong SPV anchored over the N Pole that is stable and unpressured no?

gfs-ens_Tz10_nhem_12.png

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10 minutes ago, Ralph Wiggum said:

Squeeze play...under 7 days now. Bubble of hp on W North America and another squeezing over the Middle East. Looks like the warming over Siberia is legit and the SPV is getting pummeled. I'll leave it to the experts to decipher what it means but it cant be bad. Beats a strong SPV anchored over the N Pole that is stable and unpressured no?

I admit there are some positives but as you know the GEFS is at times biased weak, at least so far this early season, while the EC has done better in strat verification forecasts. However, as you mention, we are talking under 7 days here with the GEFS, so that is a positive.  

Also, according to Simmon Lee the FV3 GFS has been doing better versus the GEFS.

A quick note on the AO ensembles -  seems the forecasted extreme positives, up to +5 or more, have been trimmed back down to about + 3, with several members taking the AO back negative shortly thereafter. As HM stated previously,  the same processes causing the AO to rise will be responsible for the upcoming decline in the NAM state.   

Meanwhile, Matt is impressed by the potential down the road.  We will also get an update soon regarding the QBO. There are some interesting evolution and progressions possible in mid- January if things work in our favor.  

This is of interest as well :

 

 

 

 

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I will gladly ride the BAMMWX train ......................where can I get my ticket ?

By the way.....I still believe in snow and in holiday spirit. Hopefully, a nice time coming up for us soon for those who enjoy cold and winter scenes of snow covered fields and streets bounded with snow in a winter wonderland.   

 

 

 

 

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36 minutes ago, Snowchaser said:

Why is no one talking about this for next week?? :rolleyes:

 

8C25FA58-C7AE-447C-9393-244CB20A8F96.jpeg.0e6cb14145bc598bdc4b5f03c08a0ccc.jpeg

Both jet streams are somewhat progressive and the NS disturbance and SS disturbance remain separated on most if not all guidance. Would need a mechanism to nudge the SS to the North and/or amplify the NS....and then of course timing a phase would be the next obstacle. Worth watching but not a threat right now.

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2 minutes ago, Ralph Wiggum said:

Both jet streams are somewhat progressive and the NS disturbance and SS disturbance remain separated on most if not all guidance. Would need a mechanism to nudge the SS to the North and/or amplify the NS....and then of course timing a phase would be the next obstacle. Worth watching but not a threat right now.

Also, that scenario would be rain.

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17 minutes ago, cbmclean said:

Went really quiet in here.

In some dead space with no imminent threat worth dissecting and huge spread in the long range so we don't really have much to discuss there. However, the pattern in general isn't a shutout so something interesting can pop up any time. Until then we quiet. 

It is kind of amusing that we start Dec tomorrow and nobody has a clue how the month will shake out in the end. Dec events don't come easy but gut hunch is saying we'll get a couple shots during the second half of the month. Maybe a 1-2' NC to Philly coastal on the 24th. Big block will keep sne under blue skies. 

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42 minutes ago, C.A.P.E. said:

Latest MJO forecast from the GEFS has tropical convection looping in Phase 2 and heading back towards the COD.

Another attempt at progressing into the "bad" phases thwarted perhaps. :weenie:

 

diagram_40days_forecast_GEFS_member.gif

2 in December isn’t as good as later in Winter. It’s kinda what we see now, not warm but typically not cold enough. I’ll take it vs the alternative though. 

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11 minutes ago, psuhoffman said:

2 in December isn’t as good as later in Winter. It’s kinda what we see now, not warm but typically not cold enough. I’ll take it vs the alternative though. 

Yeah it's pretty marginal, but if it dies there it's better than progressing into 3, and continuing through all the crap phases.

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Thru 240 on the EPS/GEFS/GEPS pattern isnt terrible. AO looks to go from positive back to neutral then negative. PNA starts then ends positive. Big EPO ridge...Aleutian low. Atl side is meh imo...nothing too exciting yet no major red flags either. Would be nice to get the NAO ridge to work in tandem with the favorable PAC teleconnections but maybe as we move thru the month.  Again, thru day 10 no significant concerns and certainly not a shutout look. And that takes us closer to mid Dec so no complaints. Those day 10+ progs with collapsing patterns and PAC air flooding the US keep being pushed back for now.

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11 minutes ago, Ralph Wiggum said:

Again, thru day 10 no significant concerns and certainly not a shutout look.

Maybe we get lucky with some snow showers this week, but the way the current pattern looks, I think we need to wait a while.   

The various indices that are normally associated with accumulating snowfall in the Northern Mid-Atlantic our not in our favor moving forward.  Yes, I know about scoring in flawed patterns, but with the time of the year, I have less confidence that happens this go around.  The end of the month still seems to be uncertain, maybe we turn colder with opportunities later  in the month.  

 

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32 minutes ago, C.A.P.E. said:

Yeah it's pretty marginal, but if it dies there it's better than progressing into 3, and continuing through all the crap phases.

A standing wave in the central Indian Ocean is kind of a wash imo. Ideally we want a standing wave near the dateline. But I’ll settle for just keeping the mjo out of amplified phases 3-6 this winter. 

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22 minutes ago, frd said:

Maybe we get lucky with some snow showers this week, but the way the current pattern looks, I think we need to wait a while.   

The various indices that are normally associated with accumulating snowfall in the Northern Mid-Atlantic our not in our favor moving forward.  Yes, I know about scoring in flawed patterns, but with the time of the year, I have less confidence that happens this go around.  The end of the month still seems to be uncertain, maybe we turn colder with opportunities later  in the month.  

 

Nothing is coming easy anytime soon and I think we can all agree on that. Not impossible tho so just letting the tape play out for a couple weeks and letting the chips fall is about all we can do. 

December is a pretty low prob winter wx month. Especially the first half. Imho- the next real window will be a progressive +pna period. Not optimal but workable. Just a guess. 

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