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Pattern Fail or Fab February 2023 Pattern Thread

ATLwxfan said:
Ok we’re good. Plenty of time left lol


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What’s odd about that storm is that it was an overrunning southern slider event with a sharp cut off on the northern edge… Hickory over to Greensboro got nothing from it. You would think that a storm with that type of amounts so late in the season would have come from an ULL
 
It won’t be fun initially but this evolution is going to play in the favor of cold ..come early mid month of march that -PNA will falter and with all the blocking overtop thats currently being modeled across all models, mischief will happen. Colder looks will probably pop up as we get closer past the first week of march. Enough for a widespread south east winter storm? Probably not. But I don’t think we can take winter weather off the table for someone in the SE in march. Euro weeklies hint at it and so does the GEFS extended. It’s only a matter of time before a colder pattern gets established, the question will be how effective will it be at making some winter weather happen come week 2 and on in March. 65998B68-DFDE-459F-A2F9-6C1D2A19B94F.jpeg
 
NickyBGuarantee said:
It won’t be fun initially but this evolution is going to play in the favor of cold ..come early mid month of march that -PNA will falter and with all the blocking overtop thats currently being modeled across all models, mischief will happen. Colder looks will probably pop up as we get closer past the first week of march. Enough for a widespread south east winter storm? Probably not. But I don’t think we can take winter weather off the table for someone in the SE in march. Euro weeklies hint at it and so does the GEFS extended. It’s only a matter of time before a colder pattern gets established, the question will be how effective will it be at making some winter weather happen come week 2 and on in March. View attachment 133444
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Colder pattern established in March , in the se. That’s funny . Good luck
 
Looks like the Canadian model(s) are the only ones showing temps 80+ for GSO and RDU. Actually for almost all of NC and SC. I thought it might have been a bit overdone.
TW
 
Everyone knows I am cold and snow weenie through and through. But to me I think we need to set our expectations up for reality. The pacific looks awful right now and it doesn't really improve all that much as of today on the Ensembles (I focus primarily on the EPS). Granted that could be a delay due to not feeling the effects of a better MJO, but the pattern I see is one that limits the SER and we moderate the above average anomalies down to average or slightly below average because of a big -NAO and consistent 50/50 combo. But the Pacific is still bad and you're dumping what little cold air we have mostly out west still.

To me snow just isn't happening this year. the pattern we are entering is one of slightly below average with a lot of cold 40 degree rains. Just look at the EPS 850 anomalies as we enter March, you can already see the winter airmasses are moderating considerably. We don't have enough legit cold air in the northern hemisphere to give anyone in the south a legit shot at snow unless you're out in Texas as most of the available cold is sitting in the Rockies still.
ecmwf-ensemble-avg-nhemi-t850_anom_stream-1676937600-1677607200-1678233600-20.gif
 
6z GFS for mid-afternoon Saturday. This would be after some sleet falls in central/northern NC. That would be a shock after Thursday's highs in the 80s:

1676988419619.png

RAH has dropped my forecast highs down into the 40s now. So maybe...
 
NickyBGuarantee said:
It won’t be fun initially but this evolution is going to play in the favor of cold ..come early mid month of march that -PNA will falter and with all the blocking overtop thats currently being modeled across all models, mischief will happen. Colder looks will probably pop up as we get closer past the first week of march. Enough for a widespread south east winter storm? Probably not. But I don’t think we can take winter weather off the table for someone in the SE in march. Euro weeklies hint at it and so does the GEFS extended. It’s only a matter of time before a colder pattern gets established, the question will be how effective will it be at making some winter weather happen come week 2 and on in March. View attachment 133444
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oh great. going to call this march pattern the pallbearer so it can let us down one more time
 
Myfrotho704_ said:
Nam is always way to cold, it was off by 7 degrees yesterday for example, it’s a known cold bias
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a lot of high temp forecasting is simply figuring out how deep boundary layer mixing gets during the day, since mixing will bring those air parcels at 850mb or wherever down adiabatically.

NAM 3km- puts boundary layer at 925mb Thursday afternoon for Richmond. Temp? 75.
nam3km_2023022206_fh36_sounding_KRIC.png

Different model- some WRF model- Boundary layer is around 890mb at same time. Temp? 77.
wrf-arw_2023022200_fh42_sounding_KRIC.png


Nam in my experience underestimates the height of where the boundary layer gets to, whereas the GFS is better or can overestimate sometimes. That's where this nam bias comes from.

But generally that's where a lot of discrepancies will come from, and it's all about just how the model renders turbulence and microphysics and those things are pretty hard to get right. I bet a lot of the NWS forecasts are betting that with how windy it is most models will underestimate the amount of mixing (and don't forget to add some downsloping in their for good measure)

That and cloud cover, but I think ya'll know this, if there's more clouds than forecasted Thursday (totally possible) then the highs will not be all time monthly records. lol.
 
ILMRoss said:
a lot of high temp forecasting is simply figuring out how deep boundary layer mixing gets during the day, since mixing will bring those air parcels at 850mb or wherever down adiabatically.

NAM 3km- puts boundary layer at 925mb Thursday afternoon for Richmond. Temp? 75.
nam3km_2023022206_fh36_sounding_KRIC.png

Different model- some WRF model- Boundary layer is around 890mb at same time. Temp? 77.
wrf-arw_2023022200_fh42_sounding_KRIC.png


Nam in my experience underestimates the height of where the boundary layer gets to, whereas the GFS is better or can overestimate sometimes. That's where this nam bias comes from.

But generally that's where a lot of discrepancies will come from, and it's all about just how the model renders turbulence and microphysics and those things are pretty hard to get right. I bet a lot of the NWS forecasts are betting that with how windy it is most models will underestimate the amount of mixing (and don't forget to add some downsloping in their for good measure)

That and cloud cover, but I think ya'll know this, if there's more clouds than forecasted Thursday (totally possible) then the highs will not be all time monthly records. lol.
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GSP doesn’t seem to be too excited about the idea of setting monthly records tomorrow. They note that the guidance that is pushing highs up over February records also start the day with clear skies… they expect that there will be cloud cover that will take most of the morning to burn off.
 
FallsLake said:
There's a small difference between the NAM and RDPS.

12z RDPS (midafternoon tomorrow):
View attachment 133488
12z NAM (midafternoon tomorrow):
View attachment 133487
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when it's cooler from georgia to VA like this - it's really all about differences in how the model is resolving how deep the boundary layer gets. guarantee you the rdps is a solid 100mb deeper than nam.
 
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