December 2021

[wfrogge]

The long range has awakened me

[andyhb]

Probably should keep a very close eye on Friday for these parts given what most of the 12z guidance is selling. Particularly on the Euro, it looks like we have a broad-based upper wave with a large (and I emphasize large) warm sector returning across the Lower/Mid Mississippi Valley. The moisture is high end for the time of year and there's plenty of shear well ahead of the front for supercells should it evolve that way. I'd even go as far to say that the Euro (and, to slightly less extent, the UK) shows a significant, widespread severe event with all hazards likely.

There are a couple of models that are less impressive, having more anticyclonic curvature aloft over the warm sector with a less organized surface low/LLJ, but they'd probably still have some degree of severe weather threat.

[Matthew]

Definitely does appear more like March wx is on the horizon.  Andy speaks I pay attention. 

[andyhb]

https://twitter.com/BeauDodson/status/1467953355045670915?s=20

When it is forecasted to be 71/66 at 9 PM in December at Paducah KY, that isn't a great omen.

[Thundersnow]

Alright, I'm paying attention.

[JHart]

While we are all paying attention, go take a look at the crescent moon surmounted by Jupiter.  Spectacular.

[StormNine]

https://twitter.com/BeauDodson/status/1467953355045670915?s=20

When it is forecasted to be 71/66 at 9 PM in December at Paducah KY, that isn't a great omen.

Even outside of severe weather dewpoints in the mid to upper 60s in the lower Ohio Valley is special by itself.

[gcbama]

While we are all paying attention, go take a look at the crescent moon surmounted by Jupiter.  Spectacular.

Looked like something from 2001 space odyssey !!!!!

[mamMATTus]

Day 4-8 Convective Outlook 
   NWS Storm Prediction Center Norman OK
   0328 AM CST Tue Dec 07 2021

   Valid 101200Z - 151200Z

   ...DISCUSSION...
   Large-scale upper troughing should continue to amplify as it moves
   eastward over the Plains on Day 4/Friday. An embedded shortwave
   trough is forecast to advance northeastward across the lower/mid MS
   Valley during the day. Latest guidance suggests that this feature
   may aid convective initiation across this region by Friday
   afternoon. Rich low-level moisture will likely have advanced
   northward as well in tandem with a northeastward-developing surface
   low over the mid MS Valley and Midwest. A fairly broad warm sector,
   with sufficient instability for surface-based thunderstorms, should
   be present from the TX/LA/MS Gulf Coast northward into parts of the
   Midwest and OH Valley. Strong low-level and deep-layer shear should
   also prove favorable for updraft rotation/organization.

   At this point, the best potential for organized severe thunderstorms
   may exist over the lower/mid MS Valley during the day Friday, as
   ascent associated with the previously mentioned embedded shortwave
   trough overspreads this region. Regardless, there remain too many
   potentially limiting factors to include 15% severe probabilities for
   Day 4/Friday at this time. Namely, the overall positive tilt to the
   upper trough and considerable amount of front-parallel flow which
   may tend to undercut thunderstorms, uncertainty over early-day
   convection contaminating the warm sector, and continued differences
   in guidance regarding the strength/placement of the low-level jet,
   particularly with southward extent. Even with these uncertainties, a
   broad area of at least marginal/isolated severe potential is evident
   for Day 4/Friday from parts of the Southeast to the OH Valley, and
   inclusion of some severe probabilities will likely be needed in the
   next outlook update.

   This marginal/isolated severe risk may persist into Day 5/Saturday
   as the upper trough moves from the central to eastern CONUS. There
   is even more uncertainty with eastward extent regarding sufficient
   low-level moisture return to support robust convection, as
   thunderstorms along the eastward-advancing cold front will probably
   outpace the already weak instability. Even so, some severe threat
   may continue on Day 5/Saturday from portions of the Southeast into
   the OH/TN Valleys and perhaps the adjacent southern/central
   Appalachians. Once the surface cold front clears the East Coast by
   Day 6/Sunday, severe potential appears very low across the CONUS
   through the rest of the forecast period.

   ..Gleason.. 12/07/2021

[StormNine]

The products at CSU are a bit concerning for our region on Friday/Friday Night.

https://twitter.com/DrAaronHill/status/1468302079244443648/photo/1

We should not sleep on troughs just because they are positively tilted. We have had outbreaks such as 5/18/1995 and 4/10/2009 that came from positively titled troughs.

[Thundersnow]

Some in the state might see some flakes flying overnight.

[StormNine]

MJO does appear to go into Phase 7 and potentially 8 later on this month.  If that is true then we should finally see a pattern that is more winter-like by sometime in the New Year/early Jan timeframe.   

[schneitzeit]

Finally exiting the weak zone, too.

[schneitzeit]

There's also some indication the AO and NAO are going to go neg. and the PNA will trend toward positive. That would be good.

[Coach B]

MJO does appear to go into Phase 7 and potentially 8 later on this month.  If that is true then we should finally see a pattern that is more winter-like by sometime in the New Year/early Jan timeframe.

84-85