Fall 2025 Medium/Long Range Discussion

[RCNYILWX]

I put together a long range pattern thoughts document for LOT staff a few days ago regarding the the impressive agreement in a cold and potentially active pattern with some staying power.

It'll be primarily -EPO driven at first but then with the stratospheric warming/SPV stretching event ongoing, that tends to translate with blocking also developing in the AO and NAO domains. If we can keep the PNA neutral to negative, could set up for a rare snowy December for a good chunk of the region.

For Chicago since 2010, the only Decembers that had both above normal snowfall and below normal temps are 2010, 2013, and 2016. Below normal temps but below normal snow occurred in 2017 and 2022. I know that Detroit had a very good December in 2017 from a much more favorable clipper track there.



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[DocATL]

Now we get to watch the models do their back and forth dance. GFS looks yuck with a stronger ridge, Canadian looks better.

[sbnwx85]

5 minutes ago, DocATL said:

GFS a big fail for next weekend into early the next week for Chi. Yuck.

The system Saturday is weaker and south. Then a cutter with rain which seems inevitable no matter what happens Saturday.

[cyclone77]

Looks like it'll take another day or two to work out the fine details with this lead wave.  Lots of moving parts.  The large scale pattern really does support a high-end storm evolving out of this immediately following the lead wave.  Hope we can sync things up properly to take advantage of it.

[sbnwx85]

I know @Chambanais pulling hard for the 00z Euro.

[A-L-E-K]

Weekend duster starting to dab out and extended losing the sauce, sad

[Baum]

1 hour ago, A-L-E-K said:

Weekend duster starting to dab out and extended losing the sauce, sad

Too soon. Let the hope and hype build for another 48-72 hours before you crush dreams.

[Baum]

Festive if anything, to open the holiday season. Maybe a whitening on the newly strung garland and lighting. Beats 62 and open golf courses in my world.

 

LATE FRIDAY NIGHT THROUGH SATURDAY, A POTENTIALLY PROLONGED   PERIOD OF WARM ADVECTION DRIVEN PRECIPITATION PAIRED WITH   SUFFICIENTLY COLD TEMPS ALOFT AND AT THE SURFACE MAY SET THE STAGE   FOR AN ACCUMULATING SNOW EVENT. WHILE THERE'S A LARGE SPECTRUM OF   PLAUSIBLE OUTCOMES AMONGST ENSEMBLE MEMBERS, THE MULTI-ENSEMBLE   PROBABILITY FOR 1"+ (10:1) SNOWFALL IN 24 HOURS CENTERED ON   SATURDAY-SATURDAY EVENING IS >=60% EVEN AT THIS EXTENDED LEAD   TIME. THE ECMWF/EPS DEPICTION HAS BEEN GENERALLY MORE ROBUST THAN   THE OTHER GUIDANCE SUITES, BUT ULTIMATELY IT'S MUCH TOO FAR OUT   FOR SPECIFICS, ASIDE FROM FEELING COMFORTABLE WITH ~60% POPS IN   THE GRIDDED FORECAST. OUR MAIN MESSAGE IS TO KEEP A CLOSE EYE ON   SUBSEQUENT FORECAST UPDATES AS THIS TIMEFRAME DRAWS CLOSER FOR THE   POTENTIAL FOR WINTER WEATHER IMPACTS TO POST-THANKSGIVING TRAVEL.    -LOT

[jlauderdal]

1 hour ago, Baum said:

Festive if anything, to open the holiday season. Maybe a whitening on the newly strung garland and lighting. Beats 62 and open golf courses in my world.

 

LATE FRIDAY NIGHT THROUGH SATURDAY, A POTENTIALLY PROLONGED   PERIOD OF WARM ADVECTION DRIVEN PRECIPITATION PAIRED WITH   SUFFICIENTLY COLD TEMPS ALOFT AND AT THE SURFACE MAY SET THE STAGE   FOR AN ACCUMULATING SNOW EVENT. WHILE THERE'S A LARGE SPECTRUM OF   PLAUSIBLE OUTCOMES AMONGST ENSEMBLE MEMBERS, THE MULTI-ENSEMBLE   PROBABILITY FOR 1"+ (10:1) SNOWFALL IN 24 HOURS CENTERED ON   SATURDAY-SATURDAY EVENING IS >=60% EVEN AT THIS EXTENDED LEAD   TIME. THE ECMWF/EPS DEPICTION HAS BEEN GENERALLY MORE ROBUST THAN   THE OTHER GUIDANCE SUITES, BUT ULTIMATELY IT'S MUCH TOO FAR OUT   FOR SPECIFICS, ASIDE FROM FEELING COMFORTABLE WITH ~60% POPS IN   THE GRIDDED FORECAST. OUR MAIN MESSAGE IS TO KEEP A CLOSE EYE ON   SUBSEQUENT FORECAST UPDATES AS THIS TIMEFRAME DRAWS CLOSER FOR THE   POTENTIAL FOR WINTER WEATHER IMPACTS TO POST-THANKSGIVING TRAVEL.    -LOT

Arriving in the Western Suburbs Saturday from Fort Lauderdale, sorry for all of us the warm air is following me north.  

[michsnowfreak]

Who wants to start the Winter medium/long range thread?

[Baum]

20 minutes ago, jlauderdal said:

Arriving in the Western Suburbs Saturday from Fort Lauderdale, sorry for all of us the warm air is following me north.  

I’m thinking not: 

Saturday

A 30 percent chance of showers. Mostly sunny, with a high near 77.

[Jackstraw]

9 hours ago, sbnwx85 said:

I know @Chambanais pulling hard for the 00z Euro.

I know I am lol. Havent seen a fantasy run like that for my area in a loooong time for late Nov/early Dec 

[A-L-E-K]

12z guidance looking to close the book on this one before a thread even gets made

[TheClimateChanger]

Record warmth prevailed across Minnesota yesterday, with record highs of 56F at Minneapolis-St. Paul and 55F at St. Cloud. Fargo reached an incredible 60F, setting a daily record and making yesterday the 3rd latest date in the calendar year on which that temperature milestone was reached or exceeded.

[DocATL]

12z guidance looking to close the book on this one before a thread even gets made

Sheesh man. You’re more negative than me. Let’s at least wait on the Euro.

[A-L-E-K]

you must be new

[sbnwx85]

15 minutes ago, A-L-E-K said:

you must be new

To be fair you are in peak form for November.

[DocATL]

To be fair you are in peak form for November.

Yeah I mean it’s early. It’s hitting like late January pessimism. Canadian further south .

[Chicago Storm]

12z guidance looking to close the book on this one before a thread even gets made

stop looking at the op gfs.

[Baum]

1 minute ago, Chicago Storm said:

stop looking at the op gfs.

You must be new

[nvck]

2 minutes ago, Chicago Storm said:

stop looking at the op gfs.

i hear the korean is the one to ride this winter....

[cyclone77]

Just now, nvck said:

i hear the korean is the one to ride this winter....

I still have a windows 95 machine cranking out NGM runs.

[ILSNOW]

12Z Euro says hold on.

[sbnwx85]

Euro pretty much the same as last night on snowfall. Maybe spreads the wealth a little more north.

[nvck]

1 minute ago, cyclone77 said:

I still have a windows 95 machine cranking out NGM runs.

i fear i'm too young to get this reference... is that like today's weenies running custom wrf models off of the 300hour GFS initial conditions?

[cyclone77]

8 minutes ago, nvck said:

i fear i'm too young to get this reference... is that like today's weenies running custom wrf models off of the 300hour GFS initial conditions?

Haha, yeah I gotta bring up the ol NGM at least once per winter season.  Yeah it was a crappy US model from the 90s/early 2000s.

[RogueWaves]

I may be one of the few hoping to whiten the ground from the first storm. Backside Wed evening overnight to Thanksgiving morning "may" bring a streamer burst or two if things line-up just right. NCEP says I have a chance

[jlauderdal]

21 hours ago, jlauderdal said:

Arriving in the Western Suburbs Saturday from Fort Lauderdale, sorry for all of us the warm air is following me north.  

Moved up the flight to Friday to get ahead of the system.  What does it mean?   Dusting at best but cold rain likely.  

Best outcome: overachiever with 12+