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Wintry The Webber/1300m/Kylo/Jon/Whatalife Storm January 12th-14th

Brick Tamland said:
So if it is wrong, do you think it will be more snow or just rain?
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I think we're looking at a nuisance/advisory level event here and a quick changeover to rain for numerous reasons. 1) The CAD is not being properly handled by the CMC/ICON or most who are looking at it on here. 2) The FV3 and Euro are basically in lockstep (and so is the CMC at H5 it just hasn't properly adjusted at the surface yet), all of which suggest a warmer outcome. I think the 12z GFS is a likely outcome, perhaps with just a brief onset of frozen as far east as CLT to Raleigh.
 
Here's a summary of the LP track and p-types from 12z runs so far.
GFS - LP track through central MS/AL then off the coast with good snows and some ice along and NW of I-85.
ICON - Similar LP track but icy for CAD regions of NC.
CMC - Similar LP track but quickly transfers off the NC coast, major ice storm for CAD regions of NC.
FV3 - TBD
UK - Don't have precip/temp maps but LP track is nearly identical to GFS/ICON.
NAM - Broad, diffuse low from LA to TN. Very dry with qpf and likely outside of it's useful range.

Overall I'd say we have good agreement on the LP track going through central MS/AL and then transferring off the NC coast. The only outlier is the 6z FV3 which is a bit further north; the 12z Euro remains TBD.
 
Then areas north of CLT will likely see longer periods of icing, seen it many times where we have gotten sleet/zr/snow around 29-32 and clt south sees a cold rain with temps near the mid 30s
 
1300m said:
I think we're looking at a nuisance/advisory level event here and a quick changeover to rain for numerous reasons. 1) The CAD is not being properly handled by the CMC/ICON or most who are looking at it on here. 2) The FV3 and Euro are basically in lockstep (and so is the CMC at H5 it just hasn't properly adjusted at the surface yet), all of which suggest a warmer outcome. I think the 12z GFS is a likely outcome, perhaps with just a brief onset of frozen as far east as CLT to Raleigh.
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To piggy back on that, I would say I’m less concerned after seeing a warmer euro and gfs last few runs for sure.
 
The 12z GFS snow line is much closer to RDU than 6z which had it at the border. Not done watching for RDU imo.
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Yeah I'm watching that, there might be a period right when the storm is offshore where CAA wraps behind due to the storm deepening, would produce a burst of snow, then change back to light rain
 
Jon said:
The 12z GFS snow line is much closer to RDU than 6z which had it at the border. Not done watching for RDU imo.
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Anyone who is 1-2 counties away from any of the frozen lines should still be watching. We haven't even reached the NAM range yet.

There's HP strength and placement, confluence impacting how far north or south the low goes, stream interaction with waves that haven't been sampled yet, etc... Lot of time left for changes good and bad. I know that the line about the energy "not being sampled yet" sometimes seems to be used by meteorologists to hedge their bets and not make a definitive forecast. I think it has merit with this storm. Any time there is potential phasing, it is extremely difficult to pin down. The energy won't be properly sampled until tomorrow around 12z, so I expect there to be changes on the modeling through 0z Friday's runs at least. We have seen models converge with this lead time and then differ again in the 2-3 day time frame when there is better data.

Just keep watching. I will...
 
Meteorologist1999 said:
Honestly that would bring ice to Northern Midlands of SC it’s further south with snowfall line on the border of SC and NC so that would mean Ice further south right??
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Most likely yes, but we would need to see 2m temps to tell if the ice translates further south.

Not sure if anyone has access to 2m U.K. temps during this storm but it would be helpful to see who is seeing zr.
 
packfan98 said:
Anyone who is 1-2 counties away from any of the frozen lines should still be watching. We haven't even reached the NAM range yet.

There's HP strength and placement, confluence impacting how far north or south the low goes, stream interaction with waves that haven't been sampled yet, etc... Lot of time left for changes good and bad. I know that the line about the energy "not being sampled yet" sometimes seems to be used by meteorologists to hedge their bets and not make a definitive forecast. I think it has merit with this storm. Any time there is potential phasing, it is extremely difficult to pin down. The energy won't be properly sampled until tomorrow around 12z, so I expect there to be changes on the modeling through 0z Friday's runs at least. We have seen models converge with this lead time and then differ again in the 2-3 day time frame when there is better data.

Just keep watching. I will...
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Speaking of sampling, here’s the euro obs coverage map. Hardly anything off the coast. It should become evident like you said by tomorrow, even though a lot of data is satellite driven...nothing better than actual obs.
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Jon said:
Speaking of sampling, here’s the euro obs coverage map. Hardly anything off the coast. It should become evident like you said by tomorrow, even though a lot of data is satellite driven...nothing better than actual obs.
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Storm will be sampled 12z and 00z tmrw. This is one of those systems where you can sometimes see large shifts in models at the time of sampling. Until then chaos will likely ensue then a quick “snap” together tomorrow as models figure it out with obs.
 
Looks like slp coming in further north on the Euro... still strong CAD signal though

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Still could change since we are still over three days out, but looking like a cold rain with perhaps a brief mix to start is becoming the increasingly likely scenario except for those in the NC mountains and maybe the western Piedmont.
 
As I was saying earlier, the Euro has fully caved to the FV3 and now tracks the low through Tennessee. Also losing the CAD signature.

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Bsud said:
I think as far as upstate this is just about a no go for anything frozen except for maybe brief onset.

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I agree the high is just a little to far north. Allowing the Low to track further north and amped up more. Meaning this is a NC event. Could be bad for some in NC


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Jimmy Hypocracy said:
That accumulation map is so dead wrong for MBY. Euro/Ukie kept spitting out 9-12” here and I ended up with 2” of crap salad. @Rain Cold did you get 4-6” in early December?
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The point was look at how far north Euro was into OH/IN. Didn’t verify. It caved the next couple of runs.

It could be right on this weekend, we will see.
 
Bsud said:
I think as far as upstate this is just about a no go for anything frozen except for maybe brief onset.

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Yep it's a no go for most of us again. We cant buy a decent CAD event anymore. This high pressure just isn't in the right position and timing is off on the low. Hopefully in a couple weeks we can get some blocking and one decent storm.
 
Just read through some of the Dec 8-10th thread. Forsythsnow posted a model summary, here it is below.
From what I could tell, the FV3 did great with track, but was too cold further south into GA and other regions. We can say that it is precise and somewhat accurate. I would give it a B for performance this time around.

The HRRR and WRF models were too cold and blasted the regions in GA too cold too early. However, they were fair for other regions. Correct me if I'm wrong, but I'll give them both a C.

The CMC was too jumpy and definitely flunked further out but I'll give it credit as I will the GFS for not being so cold, but for NC it was way too warm. Both get a C+.

The Euro was like the WRF and HRRR, too fast on the cold for GA. It otherwise was good with the track except the few wobbles but might have been too generous to some areas. B+ here.

The ICON was way too warm. F.

Lastly, the NAM seemed to perform greatly in the 3 KM runs. The mix never made it out of the mountains in GA and it was close, but maybe a bit colder for other parts further east in NC. A-.

Just my analysis from what I could tell. Feel free to correct anything I said since I might have missed something or may not have enough info.
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And here was Eric's snowfall analysis.
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Kylo said:
All 4 globals 12z. Let’s see how they do.

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Thanks for posting these. I think the key is going to be how much the energy consolidates in the Midwest and also if those heights in Canada I mentioned previously press down a little faster. Models always struggle with the northern stream and complex 5h interactions like this, IF the FV3 ends up being right then it will be a huge win for the model since it has had the further north track for a long time now compared with other models. If it ends up wrong then it will cast some serious doubt on its credibility. A LP traveling through TN vs central AL/MS is one of the key differences between models. The evolution at 5H won't become clear for another 1-2 days, the 3km NAM and the RGEM will be very helpful once we get in range.
 
Fwiw the RGEM ensembles, which tend to have an amp bias at the end of their forecast period, are VERY suppressed. This is a huge red flag IMO for the amped solutions because the RGEM ensembles should be right there with the FV3/Euro but instead most members are pretty far south especially with the initial overrunning qpf.
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Here's a look at the RGEM MSLP. Notice a majority of the members have the SLP forming around central to southern Texas. Again, a HUGE red flag here since they usually are pretty amped at this stage in the game. I use them for every winter storm and they are incredibly useful for picking up on stuff that globals later catch on to. I counted 16 that were suppresed in Central/Southern Texas area versus only 7 that are further north in agreement with the globals.
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snowlover91 said:
Fwiw the RGEM ensembles, which tend to have an amp bias at the end of their forecast period, are VERY suppressed. This is a huge red flag IMO for the amped solutions because the RGEM ensembles should be right there with the FV3/Euro but instead most members are pretty far south especially with the initial overrunning qpf.
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snowlover91 said:
Here's a look at the RGEM MSLP. Notice a majority of the members have the SLP forming around central to southern Texas. Again, a HUGE red flag here since they usually are pretty amped at this stage in the game. I use them for every winter storm and they are incredibly useful for picking up on stuff that globals later catch on to. I counted 16 that were suppresed in Central/Southern Texas area versus only 7 that are further north in agreement with the globals.
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That is very interesting. Makes you question if the globals are incorrect in how amped they are showing the system on their runs now.
 
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