Niche obs — given the unique angle of approach of this cold airmass & its narrow width, the Philly-NYC-New Haven segment of I-95 is the coldest along its entire route. I’d have to imagine that doesn’t happen often, except for back door cold fronts or relatively localized precipitation events.

The arctic front moving eastward is currently merging with the inverted trough axis over NE CT, leading to enhanced low-level convergence and a sharp increase in snow rates:

As I analyzed in much more depth in my thread last night, there are two separate near-stationary heavy snow bands this morning: 1. Training heavy snow bands over NE Mass 2. Inverted trough axis has come to a near stall over southern RI into far eastern CT

As low-level convergence increases, heavy snow is developing along the inverted trough axis in eastern LI & SE CT. The inverted trough will continue slowly moving east & tilting towards the NW-SE until temporarily stalling tomorrow as the mid-upper level flow becomes oriented parallel to its axis.

This isn’t your typical view of the Hudson River across from Manhattan — widespread ice coverage across the river this morning.

(1/2) A valuable life lesson I’ve learned: True expertise isn’t only about correctly identifying and recognizing signals — it’s also about recognizing when you *don’t* know something, or when no one can know it yet beyond a lucky guess.

The more LLMs progress in their abilities, the less the question becomes “can we use LLMs for this task” and the more it becomes “*should* we use LLMs for this task”. And there are considerations beyond ethics to take into account as well.

After some more events over the last few days I'm excited to announce I'm a lead contender for the unluckiest person of the month award

Ice buildup continues along the edges of the Hudson River — this photo is from the NJ side, there’s a lot more ice from the NYC side of the river

A very random thought I had this morning — and I’m just posting it as food for thought or to seed ideas — if you could go back to your Masters research and make changes to the methodology and approach you took to the research question(s) at hand, do you feel you’d have few or many changes?

Here’s a map you don’t see often: the place with the coldest temperature anomaly vs. average in the northern hemisphere over the last 5 days is….. Ohio

If your idea of a nice post-AMS recovery day is your parking spot blocked by a pile of snow/ice, your shovel snapping in half trying to clear it, all stores sold out of shovels, and spending hours clearing it with a hammer in 4 degree wind chills blasting your face, my AMS recovery is going great!

❄️ Snow in Tampa?? ❄️ You’ve likely heard the news by now — there’s a chance of snow in the Tampa-Sarasota corridor on Saturday night. While it’s extremely unusual, if it doesn’t happen, it’s not because it was all hype or the potential never existed. Thread for an in-depth meteorological analysis:

Now that AMS is wrapping up and I finally have a chance to breathe in between travel, I’m planning to start work on fixing underlying PolarWx server issues that’ll allow me to finally add many new features & revamp the website in the coming months. Stay tuned!

How unusual is this upcoming cold outbreak in Florida? Per the latest forecast, the cold airmass aloft is within 1-2 degrees Celsius of the **year-round** cold record from 1950-2024:

That's -38C air at 500 mb moving over the Gulf Stream this weekend 👀

What on earth did I just witness #AMS2026

You don’t know what people are dealing with behind the scenes if they don’t tell you & you don’t hear from others. You may not know they’re at a low point if you talk down to them or wave them off, but it still hurts them.

Taking off my weather hat for a moment for something more important than the forecast…today is International Holocaust Remembrance Day. I’ve shared before that my grandparents (mom’s side) are both Holocaust survivors. Please do me a favor and read their story in this thread.

You don’t know what people are dealing with behind the scenes if they don’t tell you & you don’t hear from others. You may not know they’re at a low point if you talk down to them or wave them off, but it still hurts them.

Stan Benjamin (NOAA GSL) highlights how RAOBs have a dry relative humidity bias in saturated environments, which can have major downstream implications. #AMS2026

You’ve probably heard of the NOHRSC snowfall analysis, but did you know there’s a similar national gridded analysis of freezing rain being developed? Dave Novak from WPC is highlighting work on the FRANA freezing rain analysis underway at the NWS #AMS2026

If you’re from Albany, you probably had the same reaction I did when seeing this coffee shop pop up in Houston

I know it’s Texas and it doesn’t get this cold very often but I feel like it’s not asking for much to have functioning heat in my hotel room

It’s currently snowing out in Houston, meaning #AMS2026 in Houston got more snow than when AMS was held in Boston or in Baltimore

Zach Covey summarizing his presentation in the #AMS2026 #AMSStudent2026 Science Communications breakout session: "People don't experience forecasts. They experience impacts." I dig that. That's good.

Quasi-Linear Convective Sleet (QLCS)

The radar correlation coefficient at 1.5km nicely highlights where the transition zone is between sleet and snow. The brighter zone north of #NYC shows where sleet and snow is likely occurring at the same time, and since they look different to the radar, the correlation is lower. #nywx

MRMS radar reflectivity & HRRR precipitation type over the last 24 hours. An absolutely massive storm

From the @nysmesonet.org NYC Micronet, precip averaged over NYC so far is a bit over 0.70". Central Park recorded 0.73" through 1pm. Public snow reports from NYC & vicinity so far are in the 7-9" range, indicating ratios from the all snow portion of the event averaged out to slightly over 10:1.

Lots of places closed in Houston today #AMS2026

After experiencing weather whiplash from 70 & sunny to 8 & frigid on my recent travels I find myself unsure what to do with 33 degrees in Houston. It feels cold but not “freeze the second you walk out the door” type cold

Am I disappointed I willingly left the nyc metro before what would’ve been my biggest snow in nearly a decade? Yes Was it the right move professionally? Absolutely As the saying goes you can’t have your cake and eat it

I did not have 2 long flights and 2 separate trips to the airport on my bingo card today… but thanks to a split second decision #AMS2026 here I come (but very jet lagged and sleep deprived)

I keep my personal life private but the last few weeks have been… a lot. Just too much. Definitely hoping I can make it to AMS as planned tomorrow but if not… a little extra sleep certainly wouldn’t hurt

Starting off a stormy weekend with convection headed towards Houston, TX - WPC issued a mesoscale precipitation discussion for elevated convection associated with isentropic ascent & broad synoptic forcing for ascent with 1"/hour rain rates possible in the Houston metro:

With tomorrow's snow/ice storm approaching, my focus today will be on two areas: - Ice storm in the Mid Atlantic/Southeast - Snow placement & amounts in the Northeast There are still significant differences remaining, for example the southern HRRR (left) vs. northern RRFS (right):

If you had to change travel plans for the @ametsoc.org meeting due to the storm... I'm afraid to say there's more weather to monitor on the way. There's a relatively low but non-zero chance of a southern Texas snowstorm on Friday/Saturday as a SW US trough moves into a lingering cold airmass.

Today's 53 WRS winter storm mission went as planned, and all 25 sondes will be assimilated for tonight's 00Z runs of the GFS and ECMWF. Bit of caution though, one round of sondes isn't a magic pill. Helps with initial conditions, but could take a few runs to lock in the pattern...

While AI models aren't a "magic solution", they do have strengths over physics-based NWP model biases on the synoptic scale. AI models were mostly north of NWP models, as was the case with @windbornewx.bsky.social WM-5c model which preceded the AIFS & AI-GFS with the northward trend yesterday:

This warning turned out prescient. Overnight guidance significantly adjusted towards heavy snow expanding well north into NYC, New York & New England — a scenario which very few ensemble members even hinted at yesterday.

I’d be very careful with posting snow maps for the weekend storm this far out. There’s still significant uncertainty with the amplitude & progression of both SW US + north stream troughs, which drives both the event duration & how far north heavy snow expands into the Northeast.

[Monday, January 19 Analysis] A major cross-country snow and ice storm is increasingly likely this weekend. Confidence is growing in a widespread swath of over 12" of snow & a significant ice storm. I'll cover the big picture & forecast uncertainties in this thread:

Going to write a meteorological analysis thread on it when I have more time later today… but let’s just say that travel to AMS might be absolutely crippled this weekend with a major cross-country snow/ice storm. If you’re traveling to AMS, monitor closely & plan accordingly.

It was easy to be skeptical when only the GFS showed this, but with other global models now on board with a potential tropical cyclone in the East Pacific in **January** of all months… I’d be impressed if this comes to fruition

There’s an easy way to tell posts like this are fake. None include links to a CNN article because a CNN article about it does not exist

Something I unfortunately witnessed this morning and I still can’t get out of my head… there’s a special place in hell for people that scream at and hit their dogs.

Nothing says "LLMs will replace humans and are smarter than grad students" like draining an entire Claude Opus 4.5 session on trying and failing to get it to realize it's writing incomplete code and repeatedly leaving out important functions

New year, same ole reminder to be very careful with blindly trusting AI as a fact checking source. Example: Grok claims posts of an executive order by Mamdani are fictional/forged. How do we know it’s real? It’s on the official NYC government website: www.nyc.gov/content/dam/...

Quick loop through some 2025 temperature highlights: Central Park, NYC - 6 out of the 12 months had below average temperatures, led by December with an impressive -5.1F temperature anomaly driven by remarkable persistence - almost every day had below average temperatures.