Jeff Snyder
EF5
My oh my, what do my eyes see?! A good dryline setup in the southern plains?!
00z GFS output not in yet, but the 00z NAM is agreeing relatively well with the earlier GFS runs in forecasting a strong/deep upper-level low/trough near eastern Colorado Sunday afternoon (the movement of the ULL thereafter is very different between the NAM and GFS, but my focus is on Sunday). We're just about to get into the Day 3 (SWODY3) range, but it's still far enough out such that it wouldn't be too prudent to get into too much detail. The gist is that a surface low show be located near the OK panhandle (NAM) or western KS (GFS) come Sunday afternoon, with 63-70F Tds located east a dryline that is forecast to stretch southward from the sfc low. Aloft, strong southwesterly flow looks as though it'll move into the warm sector, with flow becoming progressively more meridional with latitude (e.g. S or SSW 500mb flow north of, say, Canadian, TX). Across much of the dryline, though, tonight's NAM is showing backed low-level flow that's resulting in 45-50kts deep-layer shear that's perpendicular to the dryline. Mid-level temps will likely remain quite warm (typical for fall) across the warm sector (with much cooler midlevel temps just behind the dryline), which won't do much for tropospheric lapse rates. As such, neither the GFS nor the NAM are showing CAPE in (what I would call) the marginal to moderate range. Of course, CAPE is difficult to forecast beyond a day or two (and some would argue that GFS forecast CAPE is shady to begin with), but it doesn't look like it'll be a high CAPE (>3000 j/kg) day.
As it stands now, it looks like there's a strong possibility of tornadic supercells across western and central KS, western OK and the OK panhandle, and the TX panhandle. The uncertainty, unfortunately, is quite high, which isn't uncommon for cut-off lows in the western US. In fact, the ECMWF from this morning looks like it's about 12 hours slower than the GFS, moving the 500mb low into the western Plains Monday morning. I'm typically not too hot on warm-sector activity associated with cut-off upper-level lows, since it seems that the warm sector gets shunted well southeast of the sfc low. I suppose that a cold-core play may be valid if the upper-low ends up farther east than currently forecast, but, for now at least, it looks more like a good dryline setup than a cold-core setup. Something that is certainly worth keeping an eye on (yes, I'm ending with a preposition ;P).
00z GFS output not in yet, but the 00z NAM is agreeing relatively well with the earlier GFS runs in forecasting a strong/deep upper-level low/trough near eastern Colorado Sunday afternoon (the movement of the ULL thereafter is very different between the NAM and GFS, but my focus is on Sunday). We're just about to get into the Day 3 (SWODY3) range, but it's still far enough out such that it wouldn't be too prudent to get into too much detail. The gist is that a surface low show be located near the OK panhandle (NAM) or western KS (GFS) come Sunday afternoon, with 63-70F Tds located east a dryline that is forecast to stretch southward from the sfc low. Aloft, strong southwesterly flow looks as though it'll move into the warm sector, with flow becoming progressively more meridional with latitude (e.g. S or SSW 500mb flow north of, say, Canadian, TX). Across much of the dryline, though, tonight's NAM is showing backed low-level flow that's resulting in 45-50kts deep-layer shear that's perpendicular to the dryline. Mid-level temps will likely remain quite warm (typical for fall) across the warm sector (with much cooler midlevel temps just behind the dryline), which won't do much for tropospheric lapse rates. As such, neither the GFS nor the NAM are showing CAPE in (what I would call) the marginal to moderate range. Of course, CAPE is difficult to forecast beyond a day or two (and some would argue that GFS forecast CAPE is shady to begin with), but it doesn't look like it'll be a high CAPE (>3000 j/kg) day.
As it stands now, it looks like there's a strong possibility of tornadic supercells across western and central KS, western OK and the OK panhandle, and the TX panhandle. The uncertainty, unfortunately, is quite high, which isn't uncommon for cut-off lows in the western US. In fact, the ECMWF from this morning looks like it's about 12 hours slower than the GFS, moving the 500mb low into the western Plains Monday morning. I'm typically not too hot on warm-sector activity associated with cut-off upper-level lows, since it seems that the warm sector gets shunted well southeast of the sfc low. I suppose that a cold-core play may be valid if the upper-low ends up farther east than currently forecast, but, for now at least, it looks more like a good dryline setup than a cold-core setup. Something that is certainly worth keeping an eye on (yes, I'm ending with a preposition ;P).
