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November 2025 OBS Discussion


wdrag
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EPS, GEFS, and GEPS all have a semblance of a wintry threat centered on November 10, plus or minus a day. It's been there for a few cycles now. All the usual caveats apply. Far inland, elevated spots look to have a decent chance of flakes over the next 10 days or so. That seems fairly consistent with historical norms.

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ICON has the Nov 10 threat too. I will almost always "sell" a wintry threat near the coast this early in the season unless it's modeled in the short term. But what I'm happy to see on guidance is maybe the first decent Canadian-cold delivery of the early season. If wave timing is ideal, it's the kind of scenario that could whiten elevated NEPA, southern tier of NY, Catskills, Berks etc.

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The EC-AI is cold in the long range... probably too cold.  1000-500mb thicknesses are near or below 540dm from Nov 9 through the end of the run. They bottom out near 510dm! The GFS, CMC, and their ensembles have a solid cold "signal" too. Nothing historic or severe... but definitely wintry-precip-supporting cold. I feel like these modeled cold snaps usually moderate in time. I'm be curious to see how well it holds through the coming week.

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With respect to the GFS op vs. the GEFS... it's mostly a timing issue. The op is has a higher amplitude trof with a deeper SLP and slower progression. Such a difference is typical at that time range. That's why we generally disregard specific local weather outcomes at that range. But the signal and progression of the GFS op is similar to its ensembles.

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6 minutes ago, bluewave said:

That OP run is a big outlier among its ensembles.

 

IMG_5072.thumb.png.22c5e995f72665d99ebecee9c4c3b379.png

IMG_5071.thumb.png.ecb2f8d2b86e3240f69f02ee04d41740.png

 

 

 

 

I agree. It should also be noted that very few ensemble members show a measurable snow threat for NYC or its immediate suburbs. Yes, it's going to be unseasonably cool. But the threat to NYC and its immediate suburbs appears to be a cold rain with highs in the 40s. If a few wet flakes mixed in, it would be an early "win," but that isn't the base case. Tempting as it might be to take the GFS verbatim or amplify what is a cool synoptic situation into a wintry one (not supported right now), one should resist those temptations, starved for snow as many of us are. If things converge toward a colder, wintry outcome in the short-range, that would be different. The most likely outcome appears to be an accumulating snow threat that is confined to the Catskills, Adirondacks, and parts of Upstate New York and New England. 

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22 minutes ago, eduggs said:

With respect to the GFS op vs. the GEFS... it's mostly a timing issue. The op is has a higher amplitude trof with a deeper SLP and slower progression. Such a difference is typical at that time range. That's why we generally disregard specific local weather outcomes at that range. But the signal and progression of the GFS op is similar to its ensembles.

The Northern Stream is very dominant on both EPS and GEFS. So it’s unlikely we see a coastal storm cold enough for the kind of snows the GFS near our area in early November with a primary storm track to our north. This was the case with some of the long range OP model runs trying to bring the hurricane up the coast. Instead the primary low cut to our west and the hurricane was kicked out to the southeast. So any trailing energy will probably shear out to our SE. But  there could always be a couple of flurries if there is some lingering moisture behind the front. Just not in the way the OP GFS has.

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6 minutes ago, bluewave said:

The Northern Stream is very dominant on both EPS and GEFS. So it’s unlikely we see a coastal storm cold enough for snow near our area in early November with a primary storm track to our north. This was the case with some of the long range OP model runs trying to bring the hurricane up the coast. Instead the primary low cut to our west and the hurricane was kicked out to the southeast. 

I agree that a wintry coastal storm is unlikely. But I think your MSLP graphic at 198hrs is misleading. First, it's a snapshot in time at long range. And second, at first glance the color schemes resemble height anomalies, which is confusing.


The ensemble averaging effect almost always produces noticeable differences between an individual operational run and its ensemble average at that time range. But to my eye, the op and ensembles are in reasonably good agreement with some kind of cold wave centered around the 10th. To argue otherwise seems somewhat disingenuous.

But if the intent is to merely downplay the likelihood of accumulating snow from a coastal storm at the coast, I completely agree. But I don't think you need to label the op run as an outlier to make that point. The 1009mb off the Delaarva at 192hr on the 12z GFS is 12 hours earlier than a cluster of SLPs associated with the shortwave on the individual ensembles. But the broad representation is consistent.

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35 minutes ago, eduggs said:

I agree that a wintry coastal storm is unlikely. But I think your MSLP graphic at 198hrs is misleading. First, it's a snapshot in time at long range. And second, at first glance the color schemes resemble height anomalies, which is confusing.


The ensemble averaging effect almost always produces noticeable differences between an individual operational run and its ensemble average at that time range. But to my eye, the op and ensembles are in reasonably good agreement with some kind of cold wave centered around the 10th. To argue otherwise seems somewhat disingenuous.

But if the intent is to merely downplay the likelihood of accumulating snow from a coastal storm at the coast, I completely agree. But I don't think you need to label the op run as an outlier to make that point. The 1009mb off the Delaarva at 192hr on the 12z GFS is 12 hours earlier than a cluster of SLPs associated with the shortwave on the individual ensembles. But the broad representation is consistent.

The higher resolution ensemble charts are showing the same scenario. Very fast Pacific flow with warm ups followed by brief cooldowns. Storm track from east to west the through the Great Lakes and exiting to the east of New England.

Very little room for an amped coastal track close to the coast like the OP GFS has with that much snow. Any trailing  energy lagging behind the main low looks pretty weak and sheared out to our east. But it’s possible the upper low behind the main low could cause some moisture to linger for flurries especially higher elevations in our area.  We can always get some flurries even near the coast this time of year especially early in the day if the timing is right.

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Most snow lovers want snow whenever they can get it. Winter-season snow sticks around longer and holiday snow enhances the season. So we'd choose those scenarios if given a trade option. But it doesn't work that way. Any apparent correlation between early season snow and winter snow is likely coincidental and skewed by a small sample size.

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36 minutes ago, bluewave said:

The higher resolution ensemble charts are showing the same scenario. Very fast Pacific flow with warm ups followed by brief cooldowns. Storm track from east to west the through the Great Lakes and exiting to the east of New England.

Very little room for an amped coastal track close to the coast like the OP GFS has with that much snow. Any trailing  energy lagging behind the main low looks pretty weak and sheared out to our east. But it’s possible the upper low behind the main low could cause some moisture to linger for flurries especially higher elevations in our area.  We can always get some flurries even near the coast this time of year especially early in the day if the timing is right.

Same ole crap. We'd be lucky to get 1 winter storm all winter. 

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5 hours ago, bluewave said:

Did you try a radiation shield? I know that Ambient sells separate radiation shields for their sensors. The more expensive stations like Davis have a fan aspirated shield. 
 

https://ambientweather.com/wh31-srs-solar-radiation-shield?srsltid=AfmBOorz7EtGt-FN_WSBnQcQN8KyI1q2M0m0rrY8pdsVqiMRaXYAlYm6

https://ambientweather.com/amwesrpatean.html?srsltid=AfmBOopKyQ4VW7xznO4qgQROflDAcsKdO1GId74O8ZUjp8Tr-Oz9zXpN

Thank you. I should have mentioned that mine already came with a shield:

Screenshot_20251102-143547.png.153156776dfdc62871ca0e2e197119fb.png

So it makes sense that those shields you linked aren't compatible when I checked. It's annoying that the one it came with is not doing its job properly. 

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4 hours ago, Fantom X said:

I have the same issue with my ambient.  In the afternoon, the radiation shield has the suns shadow cast over it by the weather station itself. But in the early mornings and late afternoons, the sun is shining on the radiation shield head-on, so you see a temp spike. 

It's super annoying that something like that isn't taken into account. I was 5 degrees warmer than everyone else for a few hours this morning. 

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3 minutes ago, Sundog said:

It's super annoying that something like that isn't taken into account. I was 5 degrees warmer than everyone else for a few hours this morning. 

I had a similar issue with the Davis Vantage Vue, maybe 2-3 degrees under certain sunny conditions. It had the shield but it was small and not fan aspirated. 

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Highs will reach the upper 50s and lower 60s through Wednesday. 

A weak cold front could cross the region after midweek, perhaps touching off a few scattered showers. Highs will then fall back to the lower and middle 50s before milder conditions return for a time next weekend.

Afterward, there is the potential for a short but sharp cold shot, possibly preceded by a chilly rain.

The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.07°C and the ENSO Region 3.4 anomaly has averaged -0.48°C. La Niña conditions will likely continue through mid-winter.

The SOI was +18.96 today. 

The preliminary Arctic Oscillation (AO) was +1.073 today. 

 

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5 hours ago, Sundog said:

Thank you. I should have mentioned that mine already came with a shield:

Screenshot_20251102-143547.png.153156776dfdc62871ca0e2e197119fb.png

So it makes sense that those shields you linked aren't compatible when I checked. It's annoying that the one it came with is not doing its job properly. 

Mine does this too, but I have 2 separate thermometers for temperature since my station is poorly sited, but I knew that going in when I put it up.  

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5 hours ago, IrishRob17 said:

I had a similar issue with the Davis Vantage Vue, maybe 2-3 degrees under certain sunny conditions. It had the shield but it was small and not fan aspirated. 

I had the same with the vantage vue. When the sun hit it directly it would read about 2 degrees higher than when totally in the shade.

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