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Happy New Years Eve to all of you! Yet another well below normal temperature day to close out 2025. In fact this will be the 3rd straight month with below normal average temperatures, and we will finish the year with 7 of the 12 months with temperatures below normal. I have to crunch the final numbers tomorrow, but this will likely be a top 10 coldest December here in Chester County in the last 45 years. For many spots across the County we will remain below freezing through the weekend with below normal temperatures likely through at least the 1st week of 2026. We could see some snow showers toward midnight tonight and through the overnight hours with maybe a coating in spots. Have a safe and festive New Years Eve!!

Happy New Years Eve to all of you! Yet another well below normal temperature day to close out 2025. In fact this will be the 3rd straight month with below normal average temperatures, and we will finish the year with 7 of the 12 months with temperatures below normal. I have to crunch the final numbers tomorrow, but this will likely be a top 10 coldest December here in Chester County in the last 45 years. For many spots across the County we will remain below freezing through the weekend with below normal temperatures likely through at least the 1st week of 2026. We could see some snow showers toward midnight tonight and through the overnight hours with maybe a coating in spots. Have a safe and festive New Years Eve!!

Weenie band and rapidly falling temperatures. 2025 ending on a bang in Minneapolis.

Too end this pointless NAM Discussion at least it stopped the northward trend at 12Z noticing the northwest flow and block and now moving east with the LP

Thanks for posting this! Very cool big picture approach that I like. Maybe I’m missing something but NAO didn’t appear to look good on the Ensembles moving D10-15 500 mb graphics. Another consideration is that La Niña may become less of a factor over time which could bring in other factors like MJO.

Mid level changes leave room for continued improvement though I think, although the surface didn't change much this time. Might be a non linear sort of trend on the ground if we see earlier and stronger consolidation.

12Z GFS ain't it for the Sunday potential.

AIGFS came a bit north for Sunday but still well south. Overall the American suite has been on the side of strongest suppression for this one.

You go Don. Hope we can grab an inch here.

MJO DISCUSSION • Over the past several weeks, the MJO remains weak and disorganized, with other modes of variability being the predominant drivers of convective and circulation anomalies throughout the tropics. • La Nina related ocean/atmosphere anomalies persist, but have become more confined across portions of the equatorial Pacific. • Dynamical models have been consistent in favoring little to no reemergence of coherent subseasonal activity in the coming weeks, with large ensemble spread covering various phases in RMM space. • If any renewed MJO activity were to occur later in January, the western Pacific appears most likely based on upper-level velocity potential and lower level zonal wind anomaly forecasts. • The precipitation and tropical cyclone formation outlook relies mostly on the La Nina background state, model guidance and climatology, where additional tropical cyclogenesis is favored across the southern Indian Ocean and South Pacific. I find the bold intriguing. It insinuates the hemisphere is at present rather decoupled from the ENSO state. It matters to me ...because a lot of my own ideas for the late winter period were based upon more -ENSO contribution/correlation with other notable warm springs in the past; then combining with that the recent decadal observation of increasing pattern meanders associated with CC ... the dice seemed weighted toward warmer. If the -ENSO is struggling to couple to the pattern(s), it's unclear how long that would be the case for one...but suppose it persisted in the challenged state, that would have to be considered.

Should be another inch or so tonight before weekend warm up

GFS pretty solid up here. Puts out 3-5" of high ratio stuff.

After about 5 days of AN/much AN temps, that -EPO takes us back to NN or below by Jan 12.

Weekend slider is trending closer to something, though temps are really iffy.

If the official observation today ends up being at least 3”, it’ll be just the second December with 4 days of 3+ inches of snow (the other was 1960, which was part of a 76” winter). If we can get to 3.5”, it’ll be the first time we’ve had 4 days of 3.5” on December.

While everyone went doom and gloom yesterday the 00z EPS pumps a big Alaskan ridge by Jan 10-15 and tries to get the STJ active with some split flow.

December IMBY: Melted: 3.24" Snowfall: 17.0" Precipitation Total for 2025: 42.38 4" at the stake this morning.

He's been honking that 1985 thing for seemingly weeks now. Hopefully he scores a coup.

Fwiw pretty cool we are having an actual winter. Now we just need a bigger event eventually.

Where I sit in Sylvania, I believe we’re affected by subtle orographic descent off the glacial ridge to our northwest. I’ve seen it too many times to ignore—it often produces a noticeable drying effect, especially when systems approach from the NW.

It's your weather, you can customize it the way you want it.

Another weathergami on Monday:

Take em with a grain of salt…until under 5 days.

It's not an outright prerequisite but I like your overall approach here... What it does is changes the species. You go from Miller-A atmospheres to NJ Model Lows, which these latter kind "could be" considered Miller-B but they are not necessarily so. Either way, NJ Model low or Miller-B stressed and shredded... they move right along. The problem with Miller-B's in a fast atmosphere, the translation of the entire wave space moves along too fast and the "transfer" ( which is bs ..it's not a transfer in reality ) isn't given enough time for the new low to affect before it's expelled along the flow. Also, the speed doesn't allow the jet cross-sections to set up as proficiently either, and that offset the integrity of the new low that way. So both end up looking more sheary and shreddy and the Miller-B is challenged. NJ Model lows are systems where despite the fast flow enough amplitude occurs back west far enough to activate cyclogenesis nearing the coast... say over ~ WV ...When the nose of the jet/diffluence aloft approaches the natively intense thermal packing/+Baroclinicity near the Del Marva, a low detonates very quickly.. Sometimes bombing as she blossom out just under L.I. These clip the I-95 corridor from perhaps PHL on up to PWM. Albany may have dim sun while HFD-BOS has a 3 hour pulse of S+ with lightning and thunder. The best version of these were back in 1980s, then again around 1996. But they move really quick. 6 to 9 hours tops usually for totality.

Yes, I know JB, yada yada and he definitely has his flaws ... an interesting reminder, however, not to take the models verbatim. https://x.com/BigJoeBastardi/status/2006385108584910948