January 24-26: Miracle or Mirage Thread 2

[Scarlet Pimpernel]

1 minute ago, csnavywx said:

It does on the GFS, which tells me (regardless of whether this is correct verbatim), that we may not be done with meaningful adjustments there.

Yeah I may not have worded that the best, I was looking just at that Euro loop with the East Coast ridging.  But the GFS I guess does change more.  I'm sure there will be several more adjustments, but they don't necessarily have to all be bad (hopefully, at least!).

[wxmeddler]

Ironically, the cut-off low that is being sampled is likely not the most uncertain piece of the puzzle.

[TSSN+]

Just now, wxmeddler said:

Ironically, the cut-off low that is being sampled is likely not the most uncertain piece of the puzzle.

Most always is the northern stream. 

[Maestrobjwa]

1 minute ago, wxmeddler said:

Ironically, the cut-off low that is being sampled is likely not the most uncertain piece of the puzzle.

*Yells up to airplanes* YOU'VE GOT THE WRONG GUY!!!

Did they key in that wave because it’s what gets everything started, I guess?

[Maestrobjwa]

Just now, TSSN+ said:

Most always is the northern stream. 

The northern stream has to be THE most complicated one...my goodness.

[Diesel BrokeHer]

Calls have been coming in for a few days from electric utilities to top off massive diesel tanks. Large facilities in the VA/MD/DC area are preparing for "curtailment" (when they get their gas supply cut off and have to switch to diesel). From an energy supply stand point, the grid is expected to be quite overloaded. We're all watching your discussions VERY closely and doing our best to prepare and keep your lights on... These threads have been WILDLY helpful. THANK YOU!

[Nomz]

Kept my forecast for DC at 4-8 for tonight. Nowhere near enough model agreement to go one way or another.

[Curlyq]

Any guesses on the timing?

[Nomz]

1 minute ago, Curlyq said:

Any guesses on the timing?

Probably midnight Saturday night. Duration doesn't feel very hashed out right now.

[Imgoinhungry]

Any guesses on the timing?

Late saturday night through late sunday night. Worst of it being early Sunday morning through early afternoon.


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[Eskimo Joe]

From the source:

 

[SnowenOutThere]

Just now, Eskimo Joe said:

From the source:

 

What about (apologies for asking) the NAM, CMC, Ukmet, icon? 

[dallen7908]

26 minutes ago, LeesburgWx said:

-22 in Leesburg lmao. Going to be cold AF for sure, but this is crazy output.

TMIN biases are seen in the eastern U.S. with the operational ECMWF forecasts’ largest low biases occurring in DJF (between 1.6–2.7 °C).  The low bias is exacerbated when snow is present and the boundary layer is stable.  See Lopes et al. 2024. 

ECMWF newsletter (2018) - 

Increasing the physical realism of surface processes in a model to reduce systematic biases may increase the root-mean-square error (RMSE) because different kinds of errors may no longer partially cancel each other. For example, 2-metre temperature (T2m) is computed diagnostically in the IFS from the temperature at the lowest model level and the skin temperature. There is a limiter in the computation of T2m which becomes active in very stable, low wind situations, and which prevents the T2m from deviating too strongly from the temperature at the lowest model level. Removing this limiter would be physically desirable, but tests have shown that doing so in the current model setup increases the RMSE. 

[Jebman]

That's helpful dallen7908, but can I please have that in plain English, please? Approximately 7th grade English please.

[osfan24]

1 hour ago, jayyy said:

It’s getting away from us? The latest NBM is 12-16”… sorry to be blunt, but what the hell are you talking about?


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Yeah, I mean the trends today have obviously not been great but we are still three full days from onset and new data will feed into the models tonight. It’s also clear that none of them seem to have all the pieces exactly figured out yet. I can’t imagine folks coming this far and throwing in the towel already.

[Wetbulbs88]

This feels like 2017 when I was in NYC, but not quite as bad. The call from NWS was for 24-36"--the largest total I've ever seen from NWS--with less than 24 hours to go. By gametime they were bringing down estimates by half a foot an hour, and we basically got a sleetfest after 6". 

Hoping for the best, but this is why I didn't put my chips in yesterday. These things almost always shift around. Given what was modeled for the last day-plus, a 4-8" really isn't going to feel nearly as nice as it would have otherwise. 

[coastal front]

1 minute ago, Wetbulbs88 said:

This feels like 2017 when I was in NYC, but not quite as bad. The call from NWS was for 24-36"--the largest total I've ever seen from NWS--with less than 24 hours to go. By gametime they were bringing down estimates by half a foot an hour, and we basically got a sleetfest after 6". 

Hoping for the best, but this is why I didn't put my chips in yesterday. These things almost always shift around. Given what was modeled for the last day-plus, a 4-8" really isn't going to feel nearly as nice as it would have otherwise. 

I believe this was the 2015 blizzard that developed more east then forecast. Epic bust even down at the jersey shore for me with 18”-24” still forecast 1 hour before onset. Fished with 2”

[BristowWx]

3 minutes ago, Wetbulbs88 said:

This feels like 2017 when I was in NYC, but not quite as bad. The call from NWS was for 24-36"--the largest total I've ever seen from NWS--with less than 24 hours to go. By gametime they were bringing down estimates by half a foot an hour, and we basically got a sleetfest after 6". 

Hoping for the best, but this is why I didn't put my chips in yesterday. These things almost always shift around. Given what was modeled for the last day-plus, a 4-8" really isn't going to feel nearly as nice as it would have otherwise. 

Still gonna be cold. That hasn’t changed yet.  Fun things happen below freezing.  

[SnowenOutThere]

Nams running and their initial placement of the SW is slightly different then 18z had it. 0z on top

[Terpeast]

3 minutes ago, SnowenOutThere said:

Nams running and their initial placement of the SW is slightly different then 18z had it. 0z on top

So about the same strength and a tick further back. If nam is ingesting the new data, this hasn’t really changed anything imo. All comes down to the NE wave now

[Weather Will]

Ok, I was bored so I was curious on how the more amped models are handling the forecast of cold air.  My snapshot: WB OZ HRRR at HR 48 (Friday 7pm); compared to the 12Z Canadian at same time; 18Z GFS and 18Z EURO hypotheses: Canadian which is the most amped is under forecasting the arctic air mass.

[SnowenOutThere]

1 minute ago, Terpeast said:

So about the same strength and a tick further back. If nam is ingesting the new data, this hasn’t really changed anything imo. All comes down to the NE wave now

That's about what I gathered. Though I don't know if it has the new data. I guess we'll need to wait for the real 0z runs for that. 

[TSSN+]

1 minute ago, Terpeast said:

So about the same strength and a tick further back. If nam is ingesting the new data, this hasn’t really changed anything imo. All comes down to the NE wave now

Think also would change future conditions too. At hour 11 the sw is definitely lagging a bit more 

[weathercoins]

The NAM has the new data already? 

[coastal front]

I don’t believe the nam ingested the new data per the hurricane hunter. Gfs and euro will have it tho 

[TSSN+]

SW already lagging a bit and north stream is a bit more east. 

[87storms]

1 hour ago, MillvilleWx said:

Fall line climo will likely come into play with this one. One things for sure, it’s a QPF bomb. I’m really serious when I say areas that stay all snow will likely see 15-20” and could even get close to 2’. Best spots right now I would put across the M/D with the eastern most area near @mappy and as far north as Harrisburg. Southern edge for that potential is probably the Parrs Ridge zone down Rt27 towards Damascus/Mt Airy and points northwest. 
 

Map below is prelim thoughts and NOT my official forecast. Just an outline of thoughts right now. If you are northwest of the red line, I believe you’ll see 10+”, if you are inside the purple, I believe 12-18” is a good forecast right now. Elevations above 800’ have best chance to see 15-20”. Local maxima of 23” is the initial thought. 
 

Note, this is manly for this subforum and some of PA. I didn’t try too hard for areas outside the sub, but I will for full forecast. 

Just got back from Wegman’s near what I think is your old stomping ground…looked like it had been robbed.

Feeling pretty good about this storm up this way, though I could see how Thurmont and north might do better than Frederick proper.

[alexj7]

14 minutes ago, Wetbulbs88 said:

This feels like 2017 when I was in NYC, but not quite as bad. The call from NWS was for 24-36"--the largest total I've ever seen from NWS--with less than 24 hours to go. By gametime they were bringing down estimates by half a foot an hour, and we basically got a sleetfest after 6". 

Hoping for the best, but this is why I didn't put my chips in yesterday. These things almost always shift around. Given what was modeled for the last day-plus, a 4-8" really isn't going to feel nearly as nice as it would have otherwise. 

I was also in NYC and if I remember right, that was the storm (on some other forum) where a ~40 yr veteran but retired NWS person called bust early and was eaten alive.

[stormtracker]

3 minutes ago, TSSN+ said:

Think also would change future conditions too. At hour 11 the sw is definitely lagging a bit more 

Small things, but yeah I notice them too.  Im just looking for anything at this point.  If I see a features 3 miles further west/east north or south, I'm coping and telling myself big changes are on the way

[ravensrule]

1 minute ago, 87storms said:

Just got back from Wegman’s near what I think is your old stomping ground…looked like it had been robbed.

Feeling pretty good about this storm up this way, though I could see how Thurmont and north might do better than Frederick proper.

If you are feeling good we're going to get rocked. LFG.