SPC Day 1 Outlook

   SPC AC 261956

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0256 PM CDT Fri Mar 26 2021

   Valid 262000Z - 271200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR NEW
   HAMPSHIRE INTO WESTERN MAINE...PORTIONS OF THE SOUTHEAST...THE
   MID-SOUTH...NORTHERN KANSAS INTO SOUTHERN NEBRASKA...

   ...SUMMARY...
   A lingering threat for isolated strong/damaging wind gusts remains
   in New Hampshire into western Maine. Isolated strong to severe
   storms may persist in the southeast for a few more hours. Marginally
   severe storms are still expected late this afternoon into tonight
   across the central Plains and lower Mississippi Valley tonight.

   ...NY/VT...
   Wind and tornado probabilities have been adjusted behind a weakening
   line of convection heading east into NH/ME. This line may still
   produced isolated strong wind gusts for another hour or two.

   ...Southeast...
   Though convergence along the boundary is weak and upper-level
   forcing is exiting the region, enough boundary-layer instability and
   deep-layer shear exists for an isolated wind/hail threat until late
   afternoon.

   ...KS/NE...
   A surface-based storm remains possible near the triple point in
   south-central Nebraska. Additional elevated storms may still develop
   near the I-70 corridor in Kansas. Large hail will be the primary
   threat, though isolated damaging winds are possible.

   ...Mid-South...
   A band of warm advection thunderstorms along the northward moving
   warm front is still expected late tonight. The marginal has been
   expanded slightly eastward where confidence in an isolated hail risk
   has increased.

   ..Wendt.. 03/26/2021

   .PREV DISCUSSION... /ISSUED 1126 AM CDT Fri Mar 26 2021/

   ...Upstate NY/VT this afternoon...
   A pronounced midlevel shortwave trough and associated 995 mb surface
   cyclone will move quickly east-northeastward across upstate NY and
   northern New England this afternoon/evening.  A narrow corridor of
   surface heating and cloud breaks will spread northward/northeastward
   into upstate NY and parts of VT this afternoon, immediately in
   advance of the zone of ascent with the shortwave trough/surface
   cyclone.  A band of storms with embedded bows and/or low-topped
   supercells is expected to evolve this afternoon across upstate NY,
   with an associated threat for damaging winds, given SBCAPE of
   500-1000 J/kg, effective bulk shear in excess of 50 kt, and 50 kt
   flow within a few thousand feet of the ground.  Low-level shear may
   also be strong enough for a brief tornado with embedded small-scale
   circulations.

   ...Southeast AL/GA/Carolinas today...
   A broken band of storms is ongoing from central GA into central SC
   and eastern NC, along and just ahead of a weak, slow-moving cold
   front.  The primary associated shortwave trough is passing well
   north of this region, and forcing for ascent appears to be near or
   past peak.  Still, lingering moderate buoyancy and deep-layer
   west-southwesterly shear could support the potential for isolated
   damaging gusts and marginally severe hail, prior to the storms
   weakening by this evening.

   ...Northern KS/southeastern NE this evening...
   A lead shortwave trough over the central High Plains will eject
   east-northeastward today into early tonight, which will help
   maintain weak surface cyclogenesis across western KS through this
   afternoon.  Moisture return in the warm sector will remain quite
   limited in the wake of a prior frontal passage, but strong surface
   heating and boundary-layer dewpoints of 48-50 F could support weak
   surface-based buoyancy by late afternoon into central KS.  Surface
   heating/mixing could be sufficient for thunderstorm development
   along the surface warm front to the east of the triple point by this
   evening, where profiles would favor low-topped supercells. 
   Otherwise, the more probable scenario is for elevated convection
   this evening into early tonight across northeast KS and vicinity, in
   the warm advection zone (north of the surface front) on the nose of
   a developing low-level jet.  

   ...Mid South late tonight...
   The stalling front near the northern Gulf coast will begin to return
   northward as a warm front tonight, in response to strengthening
   southerly low-level flow downstream from a southern Rockies midlevel
   trough.  The increase in low-level flow will likewise support
   strengthening warm advection, and an increasing potential for
   thunderstorm development north of the warm front overnight into the
   Mid South.  The returning moisture and lingering midlevel lapse
   rates greater than 7 C/km will contribute to MUCAPE of 1500-2000
   J/kg, and the potential for a few strong updrafts.  Cells/clusters
   overnight will have the potential to produce isolated large hail,
   especially if any elevated supercells form given effective bulk
   shear of 35-40 kt.

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z