Severe Weather Threat Day 2 Wed Apr 10

Upper-Air Support For Svr Potential Over Conus Will Be Dominated By
Large Cyclone -- Now Evident In Moisture Channel Imagery Over
Intermountain W And Centered Over 4-Corners Region. Cyclone Center Aloft Is Expected To Move Enewd Across S-Central Rockies And Central High Plains...Reaching Swrn Neb By 11/00z.

Remarkable Consistency Is Evident Among Operational And Sref Guidance In Timing/Track Through That Time. Slgt Positive Tilt Should Be Maintained With Accompanying Synoptic Trough...As Stg Speed Max And Accompanying Basal Shortwave Perturbation Cross W-Central/Nwrn Mex.

Progged Phase Speed Of This System Starts To Differ During Latter Half Of Period Based On Impact Of Low-Amplitude Vorticity Perturbations Ejecting Newd Across Srn/Central Plains...But With Gen Consensus Of 500-Mb Low Solutions Over Ern Neb By 11/12z.

At Sfc...Frontal-Wave Cyclone Now In Early Stages Over Swrn-Central
Ks Is Expected To Organize Unsteadily Through Remainder Day-1... Before Becoming Better Defined Around Start Of Period Over Nrn Mo.

At That Point...Arctic Cold Front Now Surging Swd Across Srn High Plains Should Extend From Mo Low Swwd Across Sern Ok And
Central/S-Central Tx. Low Should Deepen And Move Slowly Across Nern Mo Through 11/00z...As Cold Front Sweeps Ewd/Sewd Over Wrn
Ozarks...Arklatex Region And Remainder Of S Tx.

Quasistationary Front Will Extend From Low Ewd Across Oh And Portions Nrn Mid-Atlc Region And Srn New England. By End Of Period...Sfc Cyclone Should Occlude Over Nwrn Il With Secondary/ Triple-Point Low Developing Farther E Along Quasistationary Front...Most Likely Over Nern Il/Nwrn Indiana Area. Cold Front Should Extend From There Swd Across Wrn Ky Then Sswwd Over Wrn Ms...Srn La And W-Central Gulf.

Ms Valley Region And Wrn Gulf Coast...

Band Of Stg-Svr Tstms Should Be Ongoing Along And/Or Behind Sfc Cold Front At Start Of Period...Offering Threat Of Ocnl Svr Hail And
Gusts. Mean-Wind And Deep-Shear Vectors Will Be Favorable For Svr
Throughout Period...Including Embedded Supercells/Bows.

However...Geometry Of Deep-Layer Winds With Respect To Frontal Zone Indicate Dominant Mode For Near-Frontal Convection Will Be

Activity Is Fcst To Shift Ewd Across Outlook Area Through Daylight
Hours...Into Progressively Destabilizing Air Mass...With Increasing
Coverage Of Svr.

Most Svr Events Should Be In Form Of Damaging Wind And Mrgl Hail ...Though A Few Tornadoes Also Are Possible. Fcst Soundings Suggest Largest Daytime Low-Level Hodographs In Mid-South
Portion Of Outlook...Overlaid With 40-50 Kt Effective Shear Magnitudes. 60s F Sfc Dew Points Will Be Common In Prefrontal Air
Mass...Contributing To 1000-2000 J/Kg Afternoon Mlcape.

Svr Threat Generally Will Wane From N-S During Evening...As Activity Moves Into Regime Of Gradual Stabilization. Exception May Be Over La/Ms And Lower Delta Region During Evening And Overnight... Where Main Band Of Convergence Impinges On Optimally Modified Moist Sector. Weakening Lapse Rates Aloft Should Be Offset By Rich Low-Level Thetae -- With Sfc Dew Points Upper 60s To Near 70 F Over Ms/La -- In Helping To Maintain Sfc-Based Effective Inflow Parcels Through Much Of Overnight Time Frame.

There Is No Specific Mesoscale Feature Apparent Along Convective Band That Would Focus More Than Isolated Potential For Significant-Severe Wind...Hail Or Strong Tornadoes...Within Relatively Dense Concentration Of Total Svr.

As Such...Will Maintain Prior Probabilities With Minor Spatial Adjustments...Where Greatest Juxtaposition Of Frontal Lift...Shear And Favorable Diurnal Thermodynamic Parameters Are Fcst...And Just Short Of Mdt-Risk Probabilistic Criteria.


Widely Scattered To Scattered Tstms Are Expected Primarily Along And N Of Quasistationary Front Through Period. Activity N Of Front Will
Pose Risk Of Ocnl Hail...With Damaging Gusts Near Front...And A
Tornado Or Two Cannot Be Ruled Out. Lack Of More Robust Low-Level Winds In Adjacent Warm Sector Keeps Hodograph Size Limited...Except In Very Narrow Frontal Corridor...Though 40-50 Kt Effective Shear Magnitudes Are Possible In Support Of Tstm Organization. 60s Sfc Dew Points Should Contribute To 1000-1500 J/Kg Mlcape During Afternoon...Locally Higher In Areas Of Most Persistent Insolation.

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