Quincy Vagell
EF4
The setup is fairly similar to what we saw today (May 17th), albeit somewhat farther east and with more storm coverage expected across Colorado and Kansas.
A surface low over eastern Colorado will probably look about the same as it did for Thursday, although some slight east/southeastward progression is expected. A dryline will extend south from the low across the southern High Plains, with some sort of boundary, which may be ill-defined, across western Kansas to western Oklahoma. One of the glaring issues with this setup as mentioned by @Dan Robinson is poor moisture quality, as the boundary layer is progged to mix out, perhaps even more so than Thursday in some areas. Area averaged forecast soundings across western Kansas show a pronounced inverted-V signature with fairly sizable temperature/dew-point spreads.
In the upper levels, troughing across the Intermountain West will gradually ease eastward, resulting in height falls (more substantial than Thursday) across the Plains. This stronger forcing is one of the main reasons that convective coverage should be more widespread. While the CAPE/shear parameter space looks favorable at a glance, i.e. 2000-3000 J/kg CAPEs with 40-50 knots of 0-6km shear from eastern Colorado into western/central Kansas, the shear vectors appear to be largely parallel to the aforementioned boundary, that will extend from the surface low in eastern Colorado into western Kansas. While shear vectors may be more perpendicular to the dryline over the OK/TX panhandles and West Texas, shear is expected to be increasingly marginal with southward extent.
Looking at the convection allowing models for some scenarios, there is strong agreement in messy storm modes that result in cells forming MCSs all over the place. An ongoing MCS (late Thursday) over the central/northern Plains may leave some sort of outflow boundary in Nebraska and/or northern Kansas, but that feature will probably be displaced too far north/northeast from more favorable upper level flow.
My guess is that the best shot at seeing some initial discrete/semi-discrete storms will be in two areas. The first would be just ahead of the surface low, near a triple point in southeastern Colorado or western Kansas. This is similar to Thursday, although stronger forcing suggests that instead of one short-lived cell, there will probably be several cells, quickly congealing into a bowing MCS. The secondary area would be over the eastern portion of the OK/TX panhandles. The two main differences between Thursday and Friday will be greater storm coverage for the latter, and weaker deep layer shear. This means that the setup may actually be less favorable than Thursday in this region.
There is a non-zero probability that outflow from overnight convection may come into play tomorrow, especially if it is able to work far enough south across Kansas. Otherwise, it will probably be a non-factor.
It looks to be another messy setup across the High Plains vicinity, but with it being May and adequate shear coinciding with moderate to locally strong instability, there will be severe storms to chase. Factors limiting this from a more significant event should prove to be a relative lack of boundary layer moisture and a tendency for messy storm modes.
One bright spot is that based on expectations, there will probably be heavy rainfall across the eastern OK/TX panhandles and western OK with this event, which should help chip away some more at the drought situation.
A surface low over eastern Colorado will probably look about the same as it did for Thursday, although some slight east/southeastward progression is expected. A dryline will extend south from the low across the southern High Plains, with some sort of boundary, which may be ill-defined, across western Kansas to western Oklahoma. One of the glaring issues with this setup as mentioned by @Dan Robinson is poor moisture quality, as the boundary layer is progged to mix out, perhaps even more so than Thursday in some areas. Area averaged forecast soundings across western Kansas show a pronounced inverted-V signature with fairly sizable temperature/dew-point spreads.
In the upper levels, troughing across the Intermountain West will gradually ease eastward, resulting in height falls (more substantial than Thursday) across the Plains. This stronger forcing is one of the main reasons that convective coverage should be more widespread. While the CAPE/shear parameter space looks favorable at a glance, i.e. 2000-3000 J/kg CAPEs with 40-50 knots of 0-6km shear from eastern Colorado into western/central Kansas, the shear vectors appear to be largely parallel to the aforementioned boundary, that will extend from the surface low in eastern Colorado into western Kansas. While shear vectors may be more perpendicular to the dryline over the OK/TX panhandles and West Texas, shear is expected to be increasingly marginal with southward extent.
Looking at the convection allowing models for some scenarios, there is strong agreement in messy storm modes that result in cells forming MCSs all over the place. An ongoing MCS (late Thursday) over the central/northern Plains may leave some sort of outflow boundary in Nebraska and/or northern Kansas, but that feature will probably be displaced too far north/northeast from more favorable upper level flow.
My guess is that the best shot at seeing some initial discrete/semi-discrete storms will be in two areas. The first would be just ahead of the surface low, near a triple point in southeastern Colorado or western Kansas. This is similar to Thursday, although stronger forcing suggests that instead of one short-lived cell, there will probably be several cells, quickly congealing into a bowing MCS. The secondary area would be over the eastern portion of the OK/TX panhandles. The two main differences between Thursday and Friday will be greater storm coverage for the latter, and weaker deep layer shear. This means that the setup may actually be less favorable than Thursday in this region.
There is a non-zero probability that outflow from overnight convection may come into play tomorrow, especially if it is able to work far enough south across Kansas. Otherwise, it will probably be a non-factor.
It looks to be another messy setup across the High Plains vicinity, but with it being May and adequate shear coinciding with moderate to locally strong instability, there will be severe storms to chase. Factors limiting this from a more significant event should prove to be a relative lack of boundary layer moisture and a tendency for messy storm modes.
One bright spot is that based on expectations, there will probably be heavy rainfall across the eastern OK/TX panhandles and western OK with this event, which should help chip away some more at the drought situation.
