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Bob Chill

December 2019 Med/Long Range Disco

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4 minutes ago, Wonderdog said:

Comparing 18z to 12z, seems the redeveloping LP is further sw and somewhat larger at 18z . Am I reading this correctly  and if so, does it mean anything significant as to its evolution?

Unfortunately the track of the upper level low is too far north the entire time. Even though you see a surface low pop right off the coast, all the best dynamics and lift are well north of us. Any phasing will take place north as well so the slp won't blow up with a CCB/deform anywhere near us. 

Is there a way we can get into legit coastal action? Yes, there is but not unless the upper level low tracks 150-200 miles south through at least southern VA (NC would be better). We have 3 days or so before models will lock into the track of the upper level low so a south trend better start at 0z tonight. Lol

I can envision 2 realistic ways we can get measurable snow. If the front running band of waa precip juices up and our column stays good we could get anywhere from an inch to maybe 4-5 inches if the stars align. The second way would be the upper level low to track far enough south so we get dynamically driven instability snow as the upper low passes under us. Wouldn't be a big event but someone could get under a band and get some heavy snowfall for a time. 

Imho- I don't see any way we can get a legit coastal storm unless there are major changes with the track of the upper low and even then we're playing with fire as these progressions often (even with a good track) love to skip over us. 

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Just a little bit stronger HP over the top next weekend and the WAA could be decent at least.  I agree with the rest that the ULL is probably a pipe dream. But we might be able to steal a couple of inches up front.

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I agree with @Bob Chill that hoping for a snowy deform band like the GFS is currently showing for the NYC-BOS corridor is tilting at windmills. 

I’m not sure which of the WAA overrunning or the ULL passage is most likely to offer snow chances. Both are likely to be fairly narrow areas and the airmass is marginal in both cases. Today’s euro probably showed max upside. 

P.S. the track shifting a bit south certainly helps the WAA chances. 

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8 minutes ago, WxUSAF said:

I agree with @Bob Chill that hoping for a snowy deform band like the GFS is currently showing for the NYC-BOS corridor is tilting at windmills. 

I’m not sure which of the WAA overrunning or the ULL passage is most likely to offer snow chances. Both are likely to be fairly narrow areas and the airmass is marginal in both cases. Today’s euro probably showed max upside. 

P.S. the track shifting a bit south certainly helps the WAA chances. 

Yea, I want to believe there's a way we can get into some coastal action but there's too much to overcome without significant changes. 18z gefs actually shifted north with ind member slp in the midwest/OH valley. This plot is not a way we get coastals. The lows to the SE have no energy to work with. The track of the primary would pull a lot of warm air to the mid levels overhead. 

gfs-ememb_lowlocs_us_24.png

 

 

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22 minutes ago, WxUSAF said:

I agree with @Bob Chill that hoping for a snowy deform band like the GFS is currently showing for the NYC-BOS corridor is tilting at windmills. 

I’m not sure which of the WAA overrunning or the ULL passage is most likely to offer snow chances. Both are likely to be fairly narrow areas and the airmass is marginal in both cases. Today’s euro probably showed max upside. 

P.S. the track shifting a bit south certainly helps the WAA chances. 

Getting that primary further east would also help a great deal. Get in central Missouri instead of Nebraska would be a start. A couple of gfs members do that.

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6 minutes ago, WinterWxLuvr said:

Getting that primary further east would also help a great deal. Get in central Missouri instead of Nebraska would be a start. A couple of gfs members do that.

UKMET a little better in that department.

UKMET 17 km undefined undefined 144.png

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3 minutes ago, yoda said:

You would think that 1035 HP on teh 00z GFS at 102 is in a good position for us...

Seems to be more frozen now, so yeah probably a function of that high. But I think it’s iffy to think we get much more than light precip with that low in Omaha.

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Significant shift on  the Gefs 6z . Primary track further south and a big cluster that pop the coastal near the Delmarva and OC ...consequently snow mean with a big jump from previous runs

Quick look at Eps and it also made a shift south overall.  Not as much as the Gefs but a bump for sure .

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I really like the north Pac SST look. @Bob Chill I know you said it was ok but given the crazy warm base state the current look might be as good as it gets. There really aren’t many truly cold pools. It’s warm and warmer. So seeing the warmest anomalies where we want them and the coldest where we want (relative to the current hot tub base state) is about all we can ask for.  It’s still kind of a blend between a PDO and a VM state but that current look is actually better for our purposes than a pure pdo look. It seems to be having the desired effect. Regardless of what modeling shows the pattern across the north Pac keeps reloading into a generally favorable one. 

I think the trend away from the crazy +AO is a natural response to the beating from above and below that the PV is taking.  I see nothing that would suggest we get some prolonged +AO of death.

Finally I see things in the Indian Ocean and western Pac that I think suggest we avoid mjo hell this year.  The sst patterns near the maritime continent have flipped.  Due to that every time an mjo wave tries to propagate into warm phases it dies and reforms back over the western Indian Ocean.  That may not continue all winter but for now it’s acting as a block on the typical mjo progression and might help save December from the expected torch.  

I continue to be cautiously optimistic in the big picture I’m seeing right now long term.  

 

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Looking over things I thought the overnight models continued to show the possibilities for front end and/or back end snows for the Dec 3 system. There are a lot of things I could discuss on the setup but will try to make this brief and just focus on some things I think/would like to see in future runs. Really the key here is keeping that closed upper low in the west as far south as possible as it makes its trek across the country. So here are some things I will be looking for.

Below we have the EPS at day 4. The Models have seemed to settle on the NS that is dropping down from the pole to play nice for the time being. Wouldn't be overly comfortable with that being the case as I have seen the models mishandle NS energy up to and inside of 24 hours. But for the time being let's assume that this will be the case otherwise nothing else that follows will mean anything. So notice without the NS breaking them down we are seeing height builds/blocking over top of our system which will counter the systems tendency to move northward through its initial eastward movement. Now what we would like to see on future runs is that feature come in stronger and/or further south.

Now if you notice the ridging in front of the system that will play a key as the system enters the central US. There are several things I am looking for with this feature as the system begins to get handed off from the initial blocking over top. Notice that we are seeing the higher height anomalies in the upper portion of the ridging. This is important, see these greater anomalies in the lower portion or even spanning the whole ridge from North to south and it is probably game over. One other feature with this ridging is notice that is making an attempt to hook over the top of the approaching system. These two features of the ridge will fight against the system gaining latitude as it begins losing the initial blocking over top. So what I would like to see are stronger height anomalies in the northern portion as well as a sharper hooking over top the system (hopefully we see a distinct hooking of the greater anomalies as well). We also want to see this feature hold on longer, the longer the better.

The final hand off with this system and probably the most crucial (if we haven't already lost the low because of too much latitude gain) is what we see when the ridging hands off to the 50/50 influence. We lose that ridging too quickly and/or it is weaker and we will see the storm gain too much latitude in a key area before the 50/50s can take over. There is one last thing I will be watching and that is the 50/50. Right now the models have been pretty steadfast on a strong system in the general area now shown. So let's assume that will be the case otherwise different placement/strength and it changes the equation. Now the one thing we are seeing with this low is it is departing NE as the system is approaching the Midwest. But have that depart 6-12 hours later (assuming we have a decently positioned upper low) and things become very interesting very quickly. ETA: Or the storm moves in quicker before the 50/50 can depart. Anything that closes the gap between those two is good.

 

EPS500s96hour.gif.8a13dca11bfbf5ea2879a31543f7f1b7.gif

 

One last comment. The roughly day 8/9 period has had my interest for several days now despite the suppressive look we have been seeing quite often on the models. I will just say my interest jumped by a couple of magnitudes after seeing the overnight runs. But day 8/9, enough said.

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The best time stamp is 6 hrs after this but you can see that there are some Gefs members that run the ull through Va now . This is only 12 of the 22 so I'm sure there are a couple more . 

6z 

f132.gif

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

Quite a bit further south with the coastal than previous runs on the mean. Might get in on a little deform action if the trends continue. :weenie:

 

HM pondering whether the numerical modeling will react the same as they did in the old days, 10 years ago he said they ( the models ) would trend colder outcomes as we get closer to the event. One thing of note, he did not mention, but I see floating around is snow cover in Eastern Canada, and to our far North,  is above normal, vast and has decent depth. A good way to deliver cold air South. 

Hey, I I'm in  for any early December snowfall, that is always a good sign. 

   

 

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Here's the UKIE at 144.  Kind of strange to see a transfer from Canada to the Delmarva...Temps seem conductive to some frozen from the WAA and perhaps some of the coastal, especially through MD.  

Ukmet 144.png

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1 hour ago, psuhoffman said:

Where’d that awful pattern go?

 

The sudden ensemble upswing of the AO to about +4 SD is now forecast a few days later to get back close to neutral. 

Would love to see some sort of dive again during December with the AO, but at least we are not going to experience a raging positive AO that lasts a while, which would be a huge concern, as already discussed here in depth.   

Meanwhile the vortex is still getting pressured and it appears that continues. Again keep it weak.  Any official SSWE is always uncertain in terms of outcomes such as coupling and areas that are effected......  yada yada yada  

There is a secondary warming being projected with decreased zonal winds being forecast.  

I am anxiously awaiting the new QBO data, I believe it will be issued early next month. Hopefully we are not stalling, but still declining.  It will be of interest to those who are looking to the QBO correlations to other years, such as 1995.    On on a quick solar note, we remain at very low levels of activity, although solar wind parameters are expected to become slightly enhanced today.  

 

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Agree @frd There's a big difference between a sudden spike to +2 or 3 or whatever and a quick relax versus a flip to a giant rotating blue ball parked for weeks/months. Too early to decide which way the current move is going to go but every day that goes by gives me confidence that we're not quickly flipping to long term doom and despair. 

@psuhoffman 

Ens are at odds down the line but the trough near HI keeps showing up so a +pna seems very logical sometime after the AO flips positive. Keeps things interesting. I am expecting a warm stretch before the pna goes up. EPS may be too fast in bringing a trough back in the east. Sig spread between eps/gefs/geps D10+. 

ETA: imho- the biggest risk for an extended crap period (like 1-2 weeks) is a trough setting up in the GOA. There's a cluster of gefs members hell bent on that happening. I'd like to think the pna saves NA from a pac air flood but the underlying risk is def there. 

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Frequent coastal storms and even this development here points to an active winter in the East according to a few mets, and I am beginning to believe it more and more. 

If those whom are calling for even transient -NAO blocks in our favored areas this winter are correct, we might be very happy snow-wise during our better climo period.  

Between varying the NAO domain state,  and more than likely having an occasional split flow pattern / active STJ moisture,  should present opportunities for us.  

gfs-ememb_lowlocs_eus_fh132_trend.gif

 

 

 

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58 minutes ago, LP08 said:

Here's the UKIE at 144.  Kind of strange to see a transfer from Canada to the Delmarva...Temps seem conductive to some frozen from the WAA and perhaps some of the coastal, especially through MD.  

Ukmet 144.png

I think the transfer is from the lp in Lake Erie.

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