Wednesday, November 29

[NorthGeorgiaWX]

Good morning!

It's COLD this morning! The cold air has settled in the low lying areas this morning, so some of you are colder than the higher elevations this morning.

 

My temperature anomaly for the month so far, today will show up tomorrow.

 

We will have another shot of cold air arriving toward the middle of next week, and that should be a pretty decent blast of cold weather. The ensembles are shown first. These are all December 7th.

 

The deterministic models are tracking the same as the ensembles.

 

The models are still struggling with the timing, strength and location of the trough.

 

Obviously, the deterministic models show a deeper trough. The ensembles are a blend of multiple model runs, so everything is smoothed out and not as amplified.

Cold and and a strong trough in the winter can bring snowy weather. This trough won't bring snow for us, but it will for the mountains just to our north. Some of the ensemble members are more generous than the deterministic models.

 

Deterministic models.

 

There is a glimmer of hope on Friday...

"A note on Friday temperatures: temps will be in the mid-30s on
early Friday morning along the ridgeline of the northeast GA
mountains, and with some forecast soundings suggesting a dry layer
below ~800 mb that could support evaporative cooling, cannot rule
out some ice pellets mixing in with rain showers. Impacts would
be essentially nil. The rest of the day will be quite raw and
rainy for northeast GA (from the northeastern Atlanta metro area
to the mountains) with highs in the low to mid-50s."

This rainfall map is for this upcoming weekend, not next week.  The heaviest rainfall totals have shifted south, but north Georgia should still get a decent amount of rain, assuming the totals don't continue the southward trend. 

[RickyD]

Negative tilt coming !!!!!!  
 

Very interesting system on the way. Sure you will be posting about it Steve. 

[NorthGeorgiaWX]

1 minute ago, RickyD said:

Negative tilt coming !!!!!!  
 

Very interesting system on the way. Sure you will be posting about it Steve. 

Just posted an image of the upper level low a minute ago.

 

[NorthGeorgiaWX]

 

 

[NorthGeorgiaWX]

Important clues for you to look at in expectation of colder air in the lower 48 states:

1. Immense Arctic (cAk) vortex forming over Siberia and the Central Asian Republics, Favors resurrection of a strong -AO styled blocking signature in about two weeks.
2. Linear Stratospheric Warming western half of North America with a stretched 10MB vortex edging toward Greenland at 384 hours. Increases the chance for cold air drainage from the Chukchi and Alaskan Peninsulas through the Prairie Provinces 3 to 4 weeks after appearance.
3. Active subtropical jet stream, associated with El Nino, deviated through Mexico into Florida and along the Gulf Stream. May lead to a storm track parallel to the Gulf Coast and Eastern Seaboard late December or in January.
4. Analogs for similar years showing a big flip to the vast -NAO signature involving Quebec, Greenland and Iceland. Linkage leading to cAk vortex position reforming in Manitoba, Ontario and/or Great Lakes.
5. Madden-Julian Oscillation may hook up to mAk gyre between the Aleutian Islands and Hawaii.
6. El Nino has begun its slow, but steady, weakening trend.

It is interesting how the new AI-inspired Google forecast equation deviated from the standard models in calling for a strong Piedmont cyclone affecting the U.S. December 8 - 11. It will take a while to sort out just how good the new scheme is, which does not seem weighted by global warming adjustments or ENSO climatology (like the ECMWF has been lately; the former star prediction scheme has overestimated precipitation in the West (particularly California)  while showing an almost crazed display of worldwide heat. The analogs have worked well so far, but none of the model guidance shows a real cold snap around and after Christmas (although both the American and European series are hinting at such a development).

I think that readings will tend to warm over much of the lower 48 states in the week before Christmas. The issue to watch is that there is some potential for a Hudson Bay vortex formation around December 12, which might, as was the case in November, depress temperatures in the Great Lakes and Northeast. All things considered, the best chances for cold east of the Rocky Mountains will likely be in January and February.
 
Prepared by Meteorologist LARRY COSGROVE on 
Saturday, December 2, 2023 at 9:45 P.M. CT

[Weatherdude]

 

[Weatherdude]

 

[TheJohnnyDee]

 

Models are moving in right direction as for now. North Georgia weather going to be good!

[Weatherdude]