Pattern December to Remember

[RainlessSnowless & Grumpy]

1984-5 is one weak to moderate La Niña very mild Dec exception to hope 2021-2 somewhat resembles for cold lovers:

Here are the MJO charts for then:

Very mild Dec 1984 (blue) was centered in mild MC:

View attachment 96356

Very cold Jan (red) was centered on cold phases:View attachment 96357

JB is already on it!

 

[GaWx]

Another thing about the moderate La Niña of 1984/5: the very mild Dec had a +AO and very strong -PNA along with a neutral NAO together with the MC dominated MJO. Jan flipped along with the cold (left side) MJO (mainly low amp by the way including some inside circle) to a very strong +PNA, -AO, and -NAO. So, even if Dec of 2021 were to end up mild, don’t give up on intense cold later. And with the MJO likely going into colder phases midmonth and later, it is far from certain that Dec ends up mild overall.

 

[NickyBGuarantee]

At the end of the day all our winter months can be above average .. all we need at the end of the day is one well timed cold front along with a low pressure of some sort just a week or two of good pattern .. which always happens at some point

 

[GaWx]

JB is already on it!

I’m laughing because it is the cold biased JB but am still hoping he’s on to something.

 

[Myfrotho704_]

Does JB not realize when typical the strat is going through a process like that, it’s typically warm at first for the eastern US, making his dec outlook not look good ? Also the MJO going against it until maybe the latter 2nd week/3rd week

 

[Myfrotho704_]

I remember the days where the GFS never wanted to ridge us and always was the model that showed us with opportunities while other models show a ridge, now it’s the model that wants to dump west

 

[NickyBGuarantee]

Does JB not realize when typical the strat is going through a process like that, it’s typically warm at first for the eastern US, making his dec outlook not look good ? Also the MJO going against it until maybe the latter 2nd week/3rd week

What is his December forecast

 

[Webberweather53]

Not sure if I shared these before, but I've used all of these websites at some point or another, many on a regular basis to make & reconstruct snow maps you see on my webpage.
The ones I use most frequently:

NCEI Image and Publication System (IPS) version 2.3 -Probably the website I use the most. Fantastic for looking at actual COOP observer reports & monthly climate reports for each state. Necessary step to check each observation because often times, for ex, Trace reports or "Missing" snowfall often isn't really missing when you look at their comments and notes. Can provide very specific details about storms in local areas

SERCC NWS NOWData - Next to NCEI's IPS (above) I use this site second most frequently to check reports.

xmACIS2 (Applied Climate System Information Tool) - This site provided the data in my most recent comment above to SD. Great for getting a quick run-down of all reports and looking for stations not provided by SERCC's NWS NOWData tool, (including trace amounts of snow/rain)

NC State Climate Office Winter Storm Database (1958-Present) -Pretty good for winter storms in the last several decades, definitely like the hourly reports of precipitation types at places like RDU, GSO, & CLT, gives me a better idea of p-type spatial distributions across the state. This database isn't all inclusive however, many storms are missing, especially prior to the 2000s.

Midwestern Regional Climate Center (MRCC) cli-MATE -Great for getting large-scale interpolated maps for storms, gives me a basic, general idea of what's going on. Again, these obs haven't been rigorously QC'd (unlike my maps) so take w/ a grain of salt.

UKMET Meteocentre NOAA 20CRv2c, NCEP-R1 SLP & 500mb maps (1851-2018) -I frequently use this to separate winter storms that may occur in rapid succession over a several day period or to determine if often lagged (by a day) COOP observer reports of snow & precip are realistic.

Community Collaborative Rain, Hail, & Snow (CoCoRaHS) Network (1998-2021) -Definitely a must for modern-era winter storms, used in conjunction w/ observer reports via NWS, social media, forums like this one, etc. it provides the backbone for many of my maps

Iowa State Environmental Mesonet NWS Product Archive (1983-Present) -A must have for reanalyzing winter storms since the 1980s.

Other sites that can help with pattern recognition or corroborate the above web pages
KNMI Climate Explorer
National Operational Hydrologic Remote Sensing Center (NOHRSC) Snow Analyses (2003-Present)
NCEI Regional Snowfall Index (RSI)
NewspaperArchive.com (for pre-1895 storms)
NOAA ESRL 20th Century Reanalysis Composites (1836-2015)
NOAA ESRL NCEP Reanalysis Composites (1948-Present)
NOAA ESRL Web-based Reanalysis Intercomparison Tools (WRIT)
NWS GSP Local Data and Research
NWS CAE Archived Weather Events and Summaries
NWS ILM Wilmington, NC Snowfall Database Since 1870
NWS Local Storm Report App
NWS RAH Past Events Archive
thunderR - online rawinsonde & ERA5 browser (hourly, 1950-present)
South Carolina Winter Weather Database (1958-2020)

 

[SD]

I remember the days where the GFS never wanted to ridge us and always was the model that showed us with opportunities while other models show a ridge, now it’s the model that wants to dump west View attachment 96358

Thumb ridges in the pacific make me a sad boy

 

[NickyBGuarantee]

I remember the days where the GFS never wanted to ridge us and always was the model that showed us with opportunities while other models show a ridge, now it’s the model that wants to dump west View attachment 96358

I wonder if somehow that piece of energy in Mexico is able to eject out East if that could mute the ridge response as the big blue advances

 

[Myfrotho704_]

Thumb ridges in the pacific make me a sad boy

The struggle periods of the 2010s was that exact ridge

 

[Rain Cold]

I remember the days where the GFS never wanted to ridge us and always was the model that showed us with opportunities while other models show a ridge, now it’s the model that wants to dump west View attachment 96358

So you're saying it's more accurate now ?

 

[Myfrotho704_]

I wonder if somehow that piece of energy in Mexico is able to eject out East if that could mute the ridge response as the big blue advances

Probably not, it would either merge into the Western trough or run into our ridge and get obliterated into a weak piece of energy

 

[Rain Cold]

Thumb ridges in the pacific make me a sad boy

Also in the north Atlantic. Dividing line sets up just west of the Triangle.

 

[SD]

The struggle periods of the 2010s was that exact ridge

When we started seeing that similar look in feb was when I hit the eject button. Once we ridge over top of the wave it's going to dig S/SSW and the SER is going to respond in some form

 

[Chazwin]

If we assume December ends up mild, there are two notable moderate La Niña winter exceptions with very mild December’s that had a cold month later when looking back to just 1950:

1971-2 had a cold Feb, the coldest of DJF by far.

1984-5 had the well know historically cold Jan!

If I remember correctly December’93 was also very mild before things flipped the last 10 days of the month and continued into most of January

 

[SD]

Booty cheeks

 

[SNOWMANN]

I work outside at a lumber mill ill take some warm weather for a few weeks. Cold Novembers seem to always give way to a warm December. Then Jan is a wild card. No worries Met winter hasn't even started lol

 

[Myfrotho704_]

Nice little Wudge under the thermal ridge wonder when it retreats how high temps get I got mid 70s

 

[Webberweather53]

If I remember correctly December’93 was also very mild before things flipped the last 10 days of the month and continued into most of January

You would be correct. Late December started with a big snowstorm in the far western Piedmont and mountains that was followed up by a low end event in the central part of the state around the 23rd. An ice storm on the 28th and 29th caused quite a few power outages in the central part of the state