Rise of the Machines: January 18-19 Winter Storm Obs Thread

[CoastalWx]

22 minutes ago, ORH_wxman said:

Growth really improved after about 830-9pm. Those 3 hours or so between 9-midnight we really stacked it up. Prob had at least 2/3rds of our accumulation during that stretch. 
 

I don’t think it ever snowed truly heavy for more than about 15 min at a time. But just very consistent efficient moderate snow with those heavier bursts mixed in which was stacking at 1-1.5” per hour. 

Yeah those echoes really moved in and it came down nicely. This was a nice event.

[weatherwiz]

I need around 84-85” to hit 100” so really need these next few weeks to step it up 

[WinterWolf]

35 minutes ago, CoastalWx said:

Yeah those echoes really moved in and it came down nicely. This was a nice event.

Glad you got the goods with this one. And it’s good to see you pleased .   

[wxsniss]

Nice little event to help get us off the mat...

My neighborhood near Coolidge Corner measured around 5.5".

Logan AP 5.3", so still haven't gotten the 6" monkey off our back... almost 4 years since the Jan 2022 blizzard.

Just came back sledding with the kids. Feels like winter should!

Another relatively windless event producing beautifully rimmed trees.

[vortex95]

1 hour ago, wxsniss said:

Nice little event to help get us off the mat...

My neighborhood near Coolidge Corner measured around 5.5".

Logan AP 5.3", so still haven't gotten the 6" monkey off our back... almost 4 years since the Jan 2022 blizzard.

Just came back sledding with the kids. Feels like winter should!

Another relatively windless event producing beautifully rimmed trees.

I would not put too much stock in Logan's record no 6" single snowstorm streak.  Why?

1) The measurement hasn't always been at Logan.  It used to be a bit more inland before the airport was built, and Logan is about the *worst* location for BOS city snow since it is surrounded by ocean on 3 sides (doesn't work well for true "city" temps either). Even in recent decades, it always hasn't been at Logan Airport, Starting the mid-90s for a number of years, as one example, it was taken 1 mi away to the N by a trained spotter.

2) The observer measurements have not always been up to par.  Too low, too high, not brushing off every 6 hr or more than once every 6 hr, and gaps in observations of snowfall as well.  This is not unique to Logan, and some major airports have great observers.  I am just pointing out the caveats/shortcomings when it comes to BOS 6" snowfall gap record.

3)  When the NWS Modernization occurred in the 90s, once ASOS was installed at climate sites, which are almost always at airports in the U.S., many routine snowfall observations where lost, and some came back, but snowfall was not considered a high priory overall.

4) Of all the major wx parameters we measure, snowfall is the hardest and least accurate due to many factors.  Here is an article that covers some of the issues:
https://news.ucar.edu/14009/snowfall-measurement-flaky-history

 

The point is Logan had 5.3" from this event.  Falling short of 6" by less than an inch is well within range of error, esp. for wet snow that compacts easily, and considering the overall challenges of measuring snowfall and long-term records not consistent or subpar at times.
 

[Baroclinic Zone]

Ended up closer to 7”

[wxsniss]

45 minutes ago, vortex95 said:

I would not put too much stock in Logan's record no 6" single snowstorm streak.  Why?

1) The measurement hasn't always been at Logan.  It used to be a bit more inland before the airport was built, and Logan is about the *worst* location for BOS city snow since it is surrounded by ocean on 3 sides (doesn't work well for true "city" temps either). Even in recent decades, it always hasn't been at Logan Airport, Starting the mid-90s for a number of years, as one example, it was taken 1 mi away to the N by a trained spotter.

2) The observer measurements have not always been up to par.  Too low, too high, not brushing off every 6 hr or more than once every 6 hr, and gaps in observations of snowfall as well.  This is not unique to Logan, and some major airports have great observers.  I am just pointing out the caveats/shortcomings when it comes to BOS 6" snowfall gap record.

3)  When the NWS Modernization occurred in the 90s, once ASOS was installed at climate sites, which are almost always at airports in the U.S., many routine snowfall observations where lost, and some came back, but snowfall was not considered a high priory overall.

4) Of all the major wx parameters we measure, snowfall is the hardest and least accurate due to many factors.  Here is an article that covers some of the issues:
https://news.ucar.edu/14009/snowfall-measurement-flaky-history

 

The point is Logan had 5.3" from this event.  Falling short of 6" by less than an inch is well within range of error, esp. for wet snow that compacts easily, and considering the overall challenges of measuring snowfall and long-term records not consistent or subpar at times.
 

Appreciate it Vortex

The flaws of KBOS/Logan snow reports (at some point near a water treatment area? jutting out into the ocean?) and poor representation of the downtown area such as Boston Commons are very familiar to this board lol

In this specific case, my own measurement of 5.5” in Coolidge Corner area and neighboring PNS reports are validating… even with some margin of error, the city probably has not yet broken 6”:

1 S Brighton                 5.5 in    1015 AM 01/19   Public
Logan AP                     5.3 in    1041 AM 01/19   Official NWS Obs
Chelsea                      5.2 in    1043 AM 01/19   Trained Spotter
Boston 6.5 SW                5.1 in    0700 AM 01/19   COCORAHS
West Roxbury                 5.0 in    0940 AM 01/19   Trained Spotter
Chelsea                      4.9 in    0848 AM 01/19   Trained Spotter
Boston 3.1 SW                4.7 in    0700 AM 01/19   COCORAHS
Logan AP                     4.6 in    0703 AM 01/19   Official NWS Obs
Chelsea                      4.5 in    0800 AM 01/19   Trained Spotter
West Roxbury                 4.3 in    0815 AM 01/19   Amateur Radio
Logan AP                     3.4 in    1200 AM 01/19

[codfishsnowman]

4 Saturday and 2.3 Sunday/early Monday....6.3 for weekend event

Very nice

[The 4 Seasons]

14 hours ago, WinterWolf said:

So for The4seasins…are we giving him total from sat and Sunday? Or does he want distinct amounts from both days? 

2 separate storms. There was about an 15-18 hour gap between the two and the pns reports are not combining them and either are all the reports coming in for the NWS interactive map, just way easier and makes more sense to treat them as two distinct events. Plus its way easier for me to gather data that way from cocorahs and COOP. 

It's all good im going through the pages to get the amounts from here. 

Thank you

[The 4 Seasons]

Snowfall totals for the Jan 18-19th system. Thanks for all the reports from everyone here, i tried to include most of them if they fit. All these maps for the 25-26 season are available at the website if and when they eventually get removed from here. 

https://www.jdjweatherconsulting.com/winter-25-26

The final call we put out was for 2-4/4-6 for most of the state and it turned out it wasn't as bad as i thought. The 4-6" line should have been around the river and east and it would have been fine. General idea was correct and the text info with locally 6+ was good. C-

Lower Northeast

Southern New England

Connecticut

[40/70 Benchmark]

Verification of Sunday Night-Early Monday Snowfall

Decent But Flawed Forecast Effort

Here are the verified region wide snowfall amounts for the storm that concluded on Monday morning versus the Eastern Mass Weather Final Call map issued on Saturday.

 

There were three primary issues with the forecast map.

1) 4-7" would have been a more appropriate range as opposed to the 3-6" range that was selected.

2) This 4-7" range should have encompassed the entire 2-4" area over Rhode Island and southeastern Massachusetts, out to about the mid cape. This is because the system became slightly more intense and tracked a bit further east than implied, which resulted in greater dynamics and more snowfall over this area.

3) Finally, the Western cut off should have been slightly more abrupt, thus the 1-3" should have extended back near the Connecticut River.

 

FINAL GRADE: B-