Jesse Risley
Staff member
It looks as if the first setup of the so-called meteorological spring may be on tap for Saturday, March 5th, offering at least the prospects for a 'gentleperson's chase' if nothing else. The system is still 5 days out and there will likely be vacillations, so for now we'll keep the discussion generalized.
A longwave troughing pattern over the eastern Pacific remains concomitant with several disturbances that eject out from the SW CONUS Friday evening and again Saturday evening into Sunday in the form of several shortwaves that traverse the central CONUS as we transition to southwestern flow beginning late week. The first major push of Gulf moisture northward into the eastern Plains and western Corn Belt commences with Td values progged in the mid to upper 50s reaching the mid-Missouri valley by Saturday morning as a warm front is poised to lift northward towards the I-90 corridor through the day on Saturday. An associated area of low pressure moves out of eastern CO and deepens as it approaches the mid-Missouri valley by Saturday evening with a strong cold front in tow, and this is associated with the penultimate shortwave that impacts the central CONUS in the FRI-early MON timeframe. The surface low initially deepens but then weakens slightly as it moves into NC/NW IA by Saturday night.
Warm sector convection looks likely with this system. Kinematics look favorable for typical early-season SVR weather, with all modes on the table, including supercells with all hazards possible. While kinematics are favorable for SVR convection, several caveats exist, including the extent of instability present, and thus overall lapse rate strength, actual storm mode, and an actual slight weakening of the surface low as it moves into IA. The biggest limiting factor at this juncture, expressed on all models, appears to be the extent of instability realized likely owed to more modest moisture depth and return and uncertainties this far out in regards to warm sector destablization. Decent EML appears to persist until later Saturday. The strenght of forcing and progged skew-T/Log-P profiles indicate eventual and perhaps relatively quick transition to a more QLCS mode is also possible, but again, still preliminary in the game to know for sure, though streamwise vorticity does appear to be present for some torndic risk if forecast soundings do indeed verify. The 06z/02 ECMWF was a bit more generous with instability than the 12z/02 NAM or the 06z/02 GFS. Placement of surface features and timing of the mid-level wave could alter the position of the greatest SVR risk, so I opted to include a broader geographic area initially as the greatest risk could be somewhere between the mid-MO valley eastward as far as far WC or NW IL.
In short, as of right now, it looks like an archetypal setup in this region for early March. I'd expect a low-end SVR event with several tornado reports, and UA profiles also indicate the potential for the typical range of non-tornadic SVR reports, including hail and some damaging wind events owed to sufficiently favorable hydrolapses evident on soundings across the region at the 78-84 hr mark as of this writing. A far more abysmal thermodynamic profile would limit this even more than it already appears to be and further temper the supercell tornado potential as well.
There's still time for things to change but it's getting close enough to warrant chatter.
J
A longwave troughing pattern over the eastern Pacific remains concomitant with several disturbances that eject out from the SW CONUS Friday evening and again Saturday evening into Sunday in the form of several shortwaves that traverse the central CONUS as we transition to southwestern flow beginning late week. The first major push of Gulf moisture northward into the eastern Plains and western Corn Belt commences with Td values progged in the mid to upper 50s reaching the mid-Missouri valley by Saturday morning as a warm front is poised to lift northward towards the I-90 corridor through the day on Saturday. An associated area of low pressure moves out of eastern CO and deepens as it approaches the mid-Missouri valley by Saturday evening with a strong cold front in tow, and this is associated with the penultimate shortwave that impacts the central CONUS in the FRI-early MON timeframe. The surface low initially deepens but then weakens slightly as it moves into NC/NW IA by Saturday night.
Warm sector convection looks likely with this system. Kinematics look favorable for typical early-season SVR weather, with all modes on the table, including supercells with all hazards possible. While kinematics are favorable for SVR convection, several caveats exist, including the extent of instability present, and thus overall lapse rate strength, actual storm mode, and an actual slight weakening of the surface low as it moves into IA. The biggest limiting factor at this juncture, expressed on all models, appears to be the extent of instability realized likely owed to more modest moisture depth and return and uncertainties this far out in regards to warm sector destablization. Decent EML appears to persist until later Saturday. The strenght of forcing and progged skew-T/Log-P profiles indicate eventual and perhaps relatively quick transition to a more QLCS mode is also possible, but again, still preliminary in the game to know for sure, though streamwise vorticity does appear to be present for some torndic risk if forecast soundings do indeed verify. The 06z/02 ECMWF was a bit more generous with instability than the 12z/02 NAM or the 06z/02 GFS. Placement of surface features and timing of the mid-level wave could alter the position of the greatest SVR risk, so I opted to include a broader geographic area initially as the greatest risk could be somewhere between the mid-MO valley eastward as far as far WC or NW IL.
In short, as of right now, it looks like an archetypal setup in this region for early March. I'd expect a low-end SVR event with several tornado reports, and UA profiles also indicate the potential for the typical range of non-tornadic SVR reports, including hail and some damaging wind events owed to sufficiently favorable hydrolapses evident on soundings across the region at the 78-84 hr mark as of this writing. A far more abysmal thermodynamic profile would limit this even more than it already appears to be and further temper the supercell tornado potential as well.
There's still time for things to change but it's getting close enough to warrant chatter.
J
Last edited:
