• Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!

Pattern Novemburrr

Webberweather53 said:
Thanks for pointing that out. I'm actually planning to eventually have a separate page just for ice storm accum maps.
Click to expand...
Correct me if I’m wrong, but didn’t the December 2002 Ice Storm not have a -PNA or at least a neutral one? I seem to remember the cold air for that storm moved into place 100% through cold air damming. Temperatures the day before the storm were well up into the 50s to near 60 in the Piedmont, but then dropped very quickly once the back door cold front moved through. Most locations were in the mid to upper 20s by the next morning.
 
Chazwin said:
Correct me if I’m wrong, but didn’t the December 2002 Ice Storm not have a -PNA or at least a neutral one? I seem to remember the cold air for that storm moved into place 100% through cold air damming. Temperatures the day before the storm were well up into the 50s to near 60 in the Piedmont, but then dropped very quickly once the back door cold front moved through. Most locations were in the mid to upper 20s by the next morning.
Click to expand...
Here's a good writeup of the event: December 4-5, 2002 Winter Storm (ncsu.edu)
 
Chazwin said:
Correct me if I’m wrong, but didn’t the December 2002 Ice Storm not have a -PNA or at least a neutral one? I seem to remember the cold air for that storm moved into place 100% through cold air damming. Temperatures the day before the storm were well up into the 50s to near 60 in the Piedmont, but then dropped very quickly once the back door cold front moved through. Most locations were in the mid to upper 20s by the next morning.
Click to expand...

There is no one-size-fits-all when it comes to CAD events. The most common way they come about is w/ a southern stream wave ejecting out of the southern Rockies & into the Great Plains, with a deep trough near Atlantic Canada & shortwave ridge building in between over the Lakes. Often times, this means days prior to CAD, there's a -PNA involved, which becomes increasingly less negative/more positive as the event nears. The composite below is one I've shown many times here and is the mean anomaly pattern for every wintry CAD/Miller B event (approximately 90 of them) in NC since 1948


1637163225994.png


Here are the corresponding MSLPa for this z500a map as a sanity check

1637163578699.png
 
If we can get the trough out of Alaska and have that retrograde back towards the Aleutians, we will absolutely be cooking with grease. I don't ever really expect snow until mid December just because everything has to absolutely line up perfectly. Even during the dead of winter it is tough but right now it's really really rare to get a substantial snow storm or really any winter weather. But it will be nice to get some really cold temps in here, especially during thanksgiving. Thanksgiving feels more festive when highs are in the 40's and low 50's compared to upper 60's and sometimes 70's.
 
FallsLake said:
from the CPC site yesterday:
PNA - Looks to go positive in the LR
AO - Looks to go strongly negative
NAO - Looks to go strongly negative.
CPC - Climate Weather Linkage: Teleconnections (noaa.gov)

This would take us out to the end of November / start of December; which the pattern/climatology at that point can produce major winter storms. So basically it's about go time for us to start hoping for winter miracles.
Click to expand...

That PNA/AO/NAO combo is what has given us some good winter storms in the past. Of course, what worked in the past might not works as well now.
 
You must log in or register to reply here.
Back
Top