Winter 2021/2022 January Thread

[John1122]

If we get low amp 8-1 into the heart of winter (Jan 15th-Feb 20th) I like our odds for more cold in the future. 

[Mr. Kevin]

Just now, John1122 said:

If we get low amp 8-1 into the heart of winter (Jan 15th-Feb 20th) I like our odds for more cold in the future. 

We dont want convection to fire up in the warm phases if we can avoid it

[Carvers Gap]

Man, the 18z GFS is a run...

[Holston_River_Rambler]

As I understand it @Mr. Kevin, convection in the tropics modulates Hadley cells, which in turn modulate the jets. Here are a couple of images:

 

source: https://www.researchgate.net/figure/Schematic-of-the-Hadley-circulation-Abbreviations-TTL-Tropical-tropopause-layer_fig1_322886947

Source:

https://www.saltworkconsultants.com/hadley-cells-and-deserts/

As to why we want it over the central Pac, I think that helps strengthen the Sub tropical jet (thus El Nino years are usually wetter than average in the southeast) but it could also be that anywhere is better than the 4/5/6 areas, when it comes to modulating the pattern for folks in the eastern US. Also keep in mind that which phase is good for us can change depending on the season and situation.

So a VP plot shows where there are divergent winds aloft, modulating the Hadley cells as seen in the above image

Example: 

Green colors indicate divergent winds aloft created by convection, while orange colors indicate convergent winds aloft. 

I can't find a current image, but Michael Ventrice has created some plots that show how the divergent winds modulate the jet (sorry the colors are different) 

 

 

TBH, I don't really know how all this correlates to the RMMs, but they were created by Wheeler and Hendon to help monitor the MJO and they use several variables to plot the circulation, in addition to VP anomalies. 

Here is info regarding the MJO calculation:

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/MJO_summary.pdf

(see section III)

There are other details to consider, but for my hobby purposes, I usually start by looking at the RMMs in the morning, then the satellite of the Western Pac using the Himawari 8 found below, to try and see how tropical convection looks

https://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=full_disk&x=10848&y=10848&z=0&angle=0&im=12&ts=1&st=0&et=0&speed=130&motion=loop&maps[borders]=white&lat=0&p[0]=geocolor&opacity[0]=1&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&draw_color=FFD700&draw_width=6

 

 

 

 

[Carvers Gap]

 

25 minutes ago, Mr. Kevin said:

Also why is it good to see alot of convection in the central Pacific? 

Here is a rough map of the MJO regions...

[Carvers Gap]

8 and 1 have had cooler SSTs this year due to the La Nina.  The current slight warming at the surface may be helping things there progress, and provide almost a weak Nino signature.  As those areas warm temporarily, the convection/rain can form there more easily.  As @jaxjagmanpoints out in the ENSO thread, cold lurks right below it.  If it upwells, the MJO hits the wall IMHO.  Tough, tough forecast after mid-month.  Our fate may rest in an accurate ocean current forecast and an accurate wind forecast which might cause the upwelling cold water in the west central Pacific.  When we get a tropical system in those areas, everything goes haywire because they basically measure outgoing longwave radiation (OLR).  Colder temps are found in cloud tops.  The OLR signatures for the MJO can get false readings which is why we had the GEFS likely get ahead of things in mid-Jan.  

[Mr. Kevin]

45 minutes ago, Holston_River_Rambler said:

@Mr. Kevin Sorry I saw that you asked about the MJO earlier, but I've hyperventilating about the current system. 

This is probably the best I've seen convection look in the central Pac in a while:

 

It is south of the equator, so not sure exactly how that squares with the MJO. 

Ventrice's VP plots to have an interesting evolution:

 

Roundy's analogue page does show what seems to me like a sensible progression through the 3rd week of January:

 

SOI also dropped to 3.82 today. 

A few more things. The mjo filtered vp200 forecast chart is confusing to me lol. What do we want to see for colder weather on those charts? The soi dropping means the stj getting active perhaps? 

[Holston_River_Rambler]

1 minute ago, Mr. Kevin said:

A few more things. The mjo filtered vp200 forecast chart is confusing to me lol. What do we want to see for colder weather and not? The soi dropping means the stj getting active perhaps?

Sadly you have tapped out my knowledge at my post above. I would go over to southern and ask Webb about what exactly the VPs mean. Divergent winds and jet modulation is sadly about as far as I have gotten so far. 

[Mr. Kevin]

Just now, Holston_River_Rambler said:

Sadly you have tapped out my knowledge at my post above. I would go over to southern and ask Webb about what exactly the VPs mean. Divergent winds and jet modulation is sadly about as far as I have gotten so far. 

I understand holston. Just trying to think of a way realistically to continue this upcoming cold pattern instead of reversing back to warm again lol. I know I'm getting ahead of myself. 

[Carvers Gap]

Just now, Mr. Kevin said:

I understand holston. Just trying to think of a way realistically to continue this upcoming cold pattern instead of reversing back to warm again lol. I know I'm getting ahead of myself. 

We want the water in regions 8-1 to warm in order to allow for convection.  That would do it.  @Daniel Boone had a great post about it earlier.

[Mr. Kevin]

4 minutes ago, Carvers Gap said:

We want the water in regions 8-1 to warm in order to allow for convection.  That would do it.  @Daniel Boone had a great post about it earlier.

Whatever it takes Carver to get things continuing. 4-6 are very warm phases

[Carvers Gap]

5 minutes ago, Mr. Kevin said:

Whatever it takes Carver to get things continuing. 4-6 are very warm phases

Have a feeling we have to deal with some 4-6 at some point.

[Carvers Gap]

Who is going to be the one to post the 18z snow total map for the entire run?  

[Daniel Boone]

There is a problem with several of the Model runs snowfall projections for portions of the area, in particular Lee County and adjacent areas of which is obvious based on topography as well as historical data. Could be a grid problem as Carvers noted while discussing with him.

    I'll speak with KMRX tomorrow and see what they know regarding this.

[BNAwx]

If we can hold on to a pattern that offers wintry potential for up to 3 weeks then I’d run with it.  No matter which winter you select, “potential” is all you can ask for in the mid-south.  I’d love for each winter to be a 1977 or 1978 or even a 1985 but those are pretty rare and we’re not back to those days climatology speaking.  For most, 1 decent snowfall changes the perception of the winter as a whole.  I’m just happy that we’re entering a stretch where we may have multiple opportunities.

[McMinnWx]

Is the NAM drunk? And the HRRR, too?

[Bigbald]

Jan 7-9 period still looks good for a light event although the 0z gfs is less enthusiastic than the prior 18z run, but 0z CMC has a nice event unfolding similiar to the 18z gfs. I think Kentucky is the main winner on that run.

 

[AMZ8990]

Memphis Int'l Airport officially reached 79° before the rain hit yesterday, tying the ALL-TIME January high temperature record, last set in 2002. It also breaks the daily record by 3°.  And the next day snow is rolling through Memphis with temps in the low 30’s.  Just short of a 50 degree swing in 24 hours, really Impressive stuff.

[Carvers Gap]

As we track the system this evening, I probably should add that both the 12z GEFS and GEPS looks pretty awesome in the long range.  Going to be some swings, but they look good.

[jaxjagman]

Really like the look after the mid month of Jan.Euro shows a upper low into East China and as it gets into South and North Korea it looks more tilted then it get into Japan its stacked.Seems possible depending on how the teleconnections work out we could have a Upper Low maybe over the Valley or close by.Lots of uncertainty ATM

[Carvers Gap]

12z EPS update.  Kind of a fun evolution of the next 15-16 days of weather.  We get a strong cold shot next weekend.  The PNA ridge pushes into the Plains(prob Chinook-eque).  Then, the pattern retrogrades into a pretty nice pattern after that.  Nice little window mid-month when the trough retrogrades westward.  EPS is 24-36 hours slow that the GEFS/GEPS combo with the trough after the third trough(the one after next weekend).  That is a great looking window.  That WAR along with the WC ridge is a great snowstorm set-up.  Again, cold shots with warm rushing-in as the cold leaves...wash, rinse, repeat.

[Carvers Gap]

With one winter storm in the books for many(not all) in the forum area, time to turn the focus to the next potential storm and next few windows of opportunity.  The 6z Euro is a little further south with the TR/FRI system.  Given that model run and the 0z CMC, to me that looks like a good opportunity for someone along a line from Memphis to Nashville and points northwestward to maybe score a light event.  Maybe some wrap around snow for the rest of us.  But until the GFS caves, probably need to keep an eye on it.  That said, the GFS is more of a quick hitting, light event for a good portion of the forum area about 100 miles north of the TN border (and northward).  The Euro is more of a NW TN and KY/TN border system(and point northward.  To me I think the CMC and Euro seems to have the TR/FR system under control.  The Euro trended slightly south at 6z, so the I-40 corridor and northward is in play...again, I tend to think the Euro is correct here.

After that, looks like a brief warm-up from the 12th-15th.    The current area of BN heights will lift out to our NE and an area of AN heights will push into the Plains(out of the Rockies) at that time.  Then, almost all global ensembles retrograde the trough(which pushes into the western Atlantic) back into the East and eventually to the mid-section of NA.  Another good window on LR modeling after the 15th.  Whether the trough continues retrograde back into the West is open great debate.   The 6z GFS shows the potential of the pattern after the 15th.  Good storm track on both the 6z EPS and 12z GEFS if it verifies.  

The MJO is coupled well with what modeling is depicting now as it shows a loop into 7 or the COD.  I would suspect it comes back to phase 8 at some point.  Almost all modeling has been pretty lousy with the MJO plots of late.  The Euro was erroneous in trying to keep the MJO out of 8.  It was correct in dragging its feet.  The GEFS was too aggressive at one point with moving it into 8.  It was correct in eventually moving into 8, albeit it appears briefly.  The Australian MJO yesterday looked reasonable, though it is certainly not infallible either.  

 

[nrgjeff]

Chart below is important enough to post twice. I just eyeball the convection on the Pacific satellite. The 200 mb divergence or 850 mb convergence or outgoing radiation all show the same thing. Why make it complicated though? Satellite is simple.

On 1/1/2022 at 6:42 PM, Carvers Gap said:

 

Here is a rough map of the MJO regions...

Now one can look at forecasts of the other variables on the models, but satellite is by far my favorite diagnostic tool. One can also loop it to get an idea for the next couple days. With up to a 7 day lag for effects in North America, that goes pretty far.

Oh yes convection is in a favorable area for cold in the Southeast. China chart is also favorable with Siberia ridge and South China storm track. See @jaxjagman above. Sometimes China and US weather go together - depending on what's going on in Alaska. 

I like 2-3 weeks of cold. Mild interlude sometime next week would not shock me. Northwest Canada ridging never really settles down, so I could go with the CFS 16-20 Day with another cold shot. 

Unfortunately that could be it. I'm joking spring starts after Martin Luther King Day. However if the mild interlude fades (to normal or cold) late next week that could be signs of a more durable cold pattern. 

[TellicoWx]

12z GEFS is first run without last night's system affecting the maps. Some decent members statewide again. To me the Euro has lost some of its shine since 2020.  Little system hopefully works out for those 40 and North that missed out this past system.

[Carvers Gap]

12z CMC is a workable look north of I-40...Plateau westward.

[TellicoWx]

5 minutes ago, Carvers Gap said:

12z CMC is a workable look north of I-40...Plateau westward.

One thing definitely going for the system if it pans out, not dealing with record warmth heading into it

[John1122]

I'd definitely take what the Canadian is selling. It and the RGEM were pretty good for this last event. I believe the Euro caught on last out of all the modeling. They were all painting with a broad brush, even the mesoscale models weren't fine tuned enough to be able to spot the extremes in small local areas with the just concluded event. You won't see many like it.

[TellicoWx]

Uh oh Euro comes a little further south with 850 low...surface low going to take more southern track

[Holston_River_Rambler]

Euro dug the energy for the late week system a bit more at 12z:

[Dsty2001]

From my experience, snow begets snow