Already lamenting an ugly forecast for Saturday ("the day"), I'm going to focus on Friday ("the day before the day").
The GFS, FIM, and ECMWF have been consistently in agreement in a pretty deep trough crossing the Rockies early this weekend, spreading some very good flow across the Plains. After a mid-week shortwave passage across the Plains, recovery will be in full swing as moisture advects back in.
The 12Z NAM bulges the DL in KS and has it farther east than the 12Z GFS, but they agree in the DL location and orientation better to the south. However, the moisture gradient in the NAM is much weaker owing to higher moisture content west of the dryline, perhaps finally responding to the immense amount of increased standing water and soil moisture from last week and subsequent latent heat flux across TX. I suspect we will see that change as the land surface model continues to "catch up" to the dramatic change in moisture content across the southern Plains.
Moisture issues aside, both models have very weak to no capping, with h7 temps of only 6-8 C. While h85 temps over far W TX and NM suggest a decent EML will form, the GFS never advects that over the moist sector. The NAM does in a limited area of OK, which actually provides for strong capping, but that doesn't even matter because...
...in both models, the trough lags the moist sector by a significant distance. With the dryline located so far east, we barely even get 30 kts of h5 flow over the DL by 00Z in either model, although the west-east gradient in wind speed is pretty sharp, so even small changes in the longitudinal placement of the DL could result in much better shear. There is decent flow below h5, so much like this past Wednesday, there could still be tornadoes across KS and OK given the degree of low-level shear and the high CAPE that is forecast. In fact, if the NAM verifies, given the strongly backed low-level flow, good moisture quality, and high CAPE, there could be a pretty significant threat along the DL/WF near the KS-NE border. The GFS is far different in this region, though.
Finally, MPAS. MPAS agrees with the DL placement across the SGP. The biggest difference between MPAS and the operational models is that it has 50+ kt h5 flow overspreading the DL in OK/KS by 00Z, thus providing for more than enough deep shear for things to get interesting. I'll go ahead and wishcast, saying I think the MPAS forecast will verify. If it does, we'll be seeing classic supercells along the dryline in TX, OK, and KS.
The GFS, FIM, and ECMWF have been consistently in agreement in a pretty deep trough crossing the Rockies early this weekend, spreading some very good flow across the Plains. After a mid-week shortwave passage across the Plains, recovery will be in full swing as moisture advects back in.
The 12Z NAM bulges the DL in KS and has it farther east than the 12Z GFS, but they agree in the DL location and orientation better to the south. However, the moisture gradient in the NAM is much weaker owing to higher moisture content west of the dryline, perhaps finally responding to the immense amount of increased standing water and soil moisture from last week and subsequent latent heat flux across TX. I suspect we will see that change as the land surface model continues to "catch up" to the dramatic change in moisture content across the southern Plains.
Moisture issues aside, both models have very weak to no capping, with h7 temps of only 6-8 C. While h85 temps over far W TX and NM suggest a decent EML will form, the GFS never advects that over the moist sector. The NAM does in a limited area of OK, which actually provides for strong capping, but that doesn't even matter because...
...in both models, the trough lags the moist sector by a significant distance. With the dryline located so far east, we barely even get 30 kts of h5 flow over the DL by 00Z in either model, although the west-east gradient in wind speed is pretty sharp, so even small changes in the longitudinal placement of the DL could result in much better shear. There is decent flow below h5, so much like this past Wednesday, there could still be tornadoes across KS and OK given the degree of low-level shear and the high CAPE that is forecast. In fact, if the NAM verifies, given the strongly backed low-level flow, good moisture quality, and high CAPE, there could be a pretty significant threat along the DL/WF near the KS-NE border. The GFS is far different in this region, though.
Finally, MPAS. MPAS agrees with the DL placement across the SGP. The biggest difference between MPAS and the operational models is that it has 50+ kt h5 flow overspreading the DL in OK/KS by 00Z, thus providing for more than enough deep shear for things to get interesting. I'll go ahead and wishcast, saying I think the MPAS forecast will verify. If it does, we'll be seeing classic supercells along the dryline in TX, OK, and KS.
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