Central PA Winter 25/26 Discussion and Obs

[Ruin]

5 minutes ago, WmsptWx said:

I'm allergic to fun.

damn 

[Jns2183]

ty for posting this I often looked for accuracy on th emodels and didnt really ever find anything like this
 

There isn't any really. I'm using a super raw method to do it by getting nohcos 24hr snowfall map based on some observations then estimated. Then getting images from models for same period. Using python to try to make sure maps are for same area because I have it map each pixel location, and RGB value and assign snow based on legend RGB value. Uploaded it all to gemeni pro and have it run that statistical analysis, pull into my notebooklm of meteorology books, papers, to help interpret, then produce nice infograph for it all. Haha, honestly it's a pain and wish I could automate it more. But worth it for first big storm to explore the concept. Take into account there are a myriad of ways to arrive at right snowfall for wrong reasons. I'm hoping it harder to arrive at large area of right snowfall for wrong reasons.

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[Ruin]

4 minutes ago, Jns2183 said:

There isn't any really. I'm using a super raw method to do it by getting nohcos 24hr snowfall map based on some observations then estimated. Then getting images from models for same period. Using python to try to make sure maps are for same area because I have it map each pixel location, and RGB value and assign snow based on legend RGB value. Uploaded it all to gemeni pro and have it run that statistical analysis, pull into my notebooklm of meteorology books, papers, to help interpret, then produce nice infograph for it all. Haha, honestly it's a pain and wish I could automate it more. But worth it for first big storm to explore the concept. Take into account there are a myriad of ways to arrive at right snowfall for wrong reasons. I'm hoping it harder to arrive at large area of right snowfall for wrong reasons.

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its still something to look at and gives a bit of info honestly we should have a way to do accuracy with model. we all know models swing and miss and sometimes they get it right. but having a accuracy model for them would be awesome. cause in a given year it feels like some of the models are in the teens for accuracy 

[AccuChris]

Latest HRRR still looks great


.

[Blizzard of 93]

6 minutes ago, AccuChris said:

Latest HRRR still looks great


.

0z High res Canadian HRDPS still looks good.

[Blizzard of 93]

0z Euro still is delivering 12 to 16 to the LSV reporting stations.

[Blizzard of 93]

0z Euro-CTP close up 

[Yardstickgozinya]

@SnowPlowGuy88Sorry man , I'm in Lisburn atm so I can't just go look but I think my neighbor owns Lawn Doctor. I see Gran U Lawn so much  when I'm in Meddeow View working I think it's got me messed up. Nevertheless I live in Timber Ridge

 

[Ruin]

12:45am update friend asked me to come over to help bring his snow blower up from the basement. we should of did it earlier I told him but any way roads are dead bars are all ready closed the wawa and sheetz are dead only cars I saw 3 in 12 miles to and back so 24 miles was 2 cop cars and one plow this was a bit normal roads but mostly highway. not any snow yet or flakes moon was even peeking out from behind the clouds a bit surprised me thought the cloud cover was thick.

[MAG5035]

Snow began here just a bit after midnight, light for now. Temp 10ºF, Dewpoint 2ºF. Its happening! 

[2001kx]

Snow just started here (Just a few flakes)

[Ruin]

6 minutes ago, MAG5035 said:

Snow began here just a bit after midnight, light for now. Temp 10ºF, Dewpoint 2ºF. Its happening! 

damn you guys in Altona always seem to snow earlier then us here 

[Yardstickgozinya]

First flakes here in lisburn, 1:11 AM

[MAG5035]

Surprised no one posted this earlier, CTP bumped up amounts areawide. My point and click is up to 13-21 inches now. 

[Burghblizz]

20 minutes ago, Ruin said:

damn you guys in Altona always seem to snow earlier then us here 

Today is actually the 26th anniversary of the Jan 25, 2000 storm. A storm that would have delivered snow to Harrisburg  before Altoona as it retrograded from the east.
 

Other than that…can’t really help you out. 

[Ruin]

20 minutes ago, MAG5035 said:

Surprised no one posted this earlier, CTP bumped up amounts areawide. My point and click is up to 13-21 inches now. 

Ah wow I just clicked updated forecast now says 6 to 8 lol

[Homie J]

Already got banding here in State College

[Ruin]

first flakes outside harrisburg big fat flakes 

 

[MAG5035]

8 minutes ago, Ruin said:

Ah wow I just clicked updated forecast now says 6 to 8 lol

In Harrisburg? 

 

[Ruin]

12 minutes ago, MAG5035 said:

In Harrisburg? 

 

hmmm thats odd when I looked for some reason the write up doesnt include early this morning or lets say sat night tech we are in sunday but I know depending they sometime say well night ends at 6am. it it says today snow heavy at times 3-5 inchs tonight snow ending early 1-3 inches. Ill try another site 

[Jns2183]

Took the 0z observed soundings in Nashville and Greensboro n/c and compared them to 0z hour on 18z run of hrrr, nam, GFS.

Subject: 00z Sounding Validation Analysis: Mid-Level (850-500 hPa) Model Performance Report
This analysis evaluates the handling of the mid-tropospheric environment for the January 25, 2026, 00z cycle. Validation is performed against observed balloon soundings at Nashville (KBNA) and Greensboro (KGSO), focusing on thermal profiles, moisture depth, and vertical motion (omega).
I. Nashville, TN (KBNA) - Analysis of Pre-System Moistening
The 00z KBNA sounding revealed a transition toward a more saturated mid-level environment as synoptic-scale lift began to overspread the region.
* Mid-Level Warmth (Thermal Profile)
* HRRR Performance: Exceptional handling of the 850-500 hPa lapse rates. The HRRR achieved an RMSE of 0.57°C, accurately resolving the cooling trend at the 700 hPa level (-2.4°C observed).
* NAM/GFS Performance: Both models exhibited a notable warm bias in the mid-layers. RMSE values hovered around 0.93°C, with both models over-forecasting the 700-500 hPa thickness, likely due to slightly aggressive warm air advection (WAA) timing.
* Mid-Level Moisture (Saturation Depth)
* HRRR Performance: Most representative of the moisture plume depth. It maintained a Dew Point RMSE of 1.05°C, correctly identifying the saturation of the mid-levels.
* NAM/GFS Performance: These models were too aggressive with the "dry slot," keeping the 700-500 hPa layer too dry compared to the observed moisture. This would have resulted in an under-forecast of mid-level cloud opacity.
* Mid-Level Lift (Omega/Vertical Velocity)
* HRRR/NAM Alignment: Both models correctly signaled weak but consistent large-scale ascent. Observed Omega values in the mid-levels ranged between -0.1 and -0.3 µb/s.
* GFS Performance: Too neutral. The GFS failed to capture the subtle dynamic lift associated with the incoming shortwave, lagging behind the high-resolution guidance.
II. Greensboro, NC (KGSO) - Analysis of Subsidence and Dry Stability
In contrast to Nashville, the Greensboro environment was dominated by a dry, stable mid-level regime associated with a prominent subsidence inversion.
* Mid-Level Warmth (Thermal Profile)
* HRRR Performance: Led the field with an RMSE of 1.16°C. It was the only model to successfully resolve the sharp gradient of the subsidence inversion near the 800-750 hPa layer.
* NAM/GFS Performance: Poor handling of the stable layer. Both were significantly too warm (RMSE 1.89°C to 2.12°C), essentially "washing out" the inversion and over-predicting the mid-level temperature.
* Mid-Level Moisture (Dry Layer Integrity)
* HRRR Performance: Closest match to the observed dry slot with an RMSE of 1.80°C. It maintained the integrity of the dry mid-level air.
* NAM Performance: Major outlier. The NAM exhibited a massive moisture bias (RMSE 5.11°C). It forecasted a nearly saturated mid-troposphere, whereas the sounding showed a significant dew point depression. This represents a significant failure in boundary layer/mid-level moisture mixing.
* Mid-Level Lift (Omega/Vertical Velocity)
* HRRR/GFS Alignment: Correctly identified the sinking motion (subsidence) prevalent in the post-frontal/high-pressure regime. Both showed positive Omega values (descending air) of +0.1 to +0.4 µb/s.
* NAM Performance: Showed very weak, nearly neutral vertical motion. This lack of sinking air likely explains why the NAM failed to keep the mid-levels dry.
III. Summary Numerical Ranking (850-500 hPa Layer)
Scores are based on a normalized average of RMSE across Temperature, Dew Point, and Wind components specifically within the mid-troposphere.
* HRRR (Score: 0.72) — TOP TIER
* The clear winner for vertical resolution. It is the only model currently capable of resolving sharp inversions and mid-level moisture gradients with high accuracy.
* GFS (Score: 1.08) — MID TIER
* Reliable for general synoptic trends but lacked the resolution to handle the specific thermal structure of the inversion at KGSO and the lift at KBNA.
* NAM-Nest (Score: 1.25) — LOW TIER
* Significant moisture handling issues at KGSO and a persistent warm bias in stable layers. Use with caution for cloud cover and precipitation type forecasting in this regime.
Technical Conclusion
For practitioners focusing on mid-level dynamic features (e.g., cloud depth, precipitation efficiency, or lapse rate steepness), the HRRR is currently providing the most reliable guidance. The NAM is currently showing a high "false alarm" rate for mid-level moisture in high-stability regimes.


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[Jns2183]

hmmm thats odd when I looked for some reason the write up doesnt include early this morning or lets say sat night tech we are in sunday but I know depending they sometime say well night ends at 6am. it it says today snow heavy at times 3-5 inchs tonight snow ending early 1-3 inches. Ill try another site 

I'm near capital city airport and it says snow mainly after 3am 2"-4"
Day 6"-10"
Night 1"-2"
9"-16"

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[MAG5035]

The first heavier band has arrived and it is ripping here..probably working on an inch or so already. Decent flake size and it’s fluff. Temp is down to 9ºF, which is nuts for an event like this. 

[Festus]

Just started here.  Everything has insta-caved.  14/4.

[Ruin]

it was very light snow now its back to cloud cover after I just let my dog out this is annoying only a bit of snow on the grass and side walk

 

[Jns2183]

It truly is NAM vs world. Even the RRFS gives kmdt 11" with everyone else 12"-19" with most 13"-17". The nam and 3k are 7". I compared latest runs of 13 models below

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[Yardstickgozinya]

Very nice moderate snow here. Somewhere around a half inch.  Heading out from my track home from lisburn, back to home. Good luck fellows, Stay safe.

[Voyager]

Just got up (4:30am), so I don't know when it started, but eyeballing a half inch under moderate snow.

Temp is a balmy 8 degrees here.

[Yardstickgozinya]

I definitely underestimated the amount of snow once I walked out away from my buddy's house and got on to the road. There. was probably closer to or just slightly over 1" when I left his house. I've stopped to breather and post under the overhang at phat boy's pizza. Light snow at the moment.Hopefully things pick up.I was hoping for a challenge tonight and to finally test out this storm gear I bought seven years ago.