SPC AC 271947

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0247 PM CDT Thu Mar 27 2025

   Valid 272000Z - 281200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
   CENTRAL PLAINS TO LOWER MISSOURI/MIDDLE MISSISSIPPI VALLEYS AND
   SOUTH TEXAS...

   ...SUMMARY...
   Isolated to scattered large hail and localized severe wind gusts are
   possible across parts of the Lower Missouri/Mid-Mississippi Valleys.

   ...20z Update...
   The Slight Risk was removed from portions of northeastern Kansas
   into southwestern Iowa and northwestern Missouri. It appears there
   remains a conditional risk of a storm or two redeveloping in this
   region through the afternoon/late evening, but overall coverage of
   severe risk will remain low. Within this region, a pseudo stationary
   front/warm front is located, with large scale forcing weak in the
   absence of any pronounced upper-level trough. Through the afternoon
   and evening, low-level jet response is expected which will help
   augment weaker forcing and aid in thunderstorm development but
   consensus is mainly for storms across far western Missouri into
   central Iowa. Within this region, storms are expected to be largely
   elevated, with potential primarily being large hail and a severe
   gust or two. Overall, the severe threat is appropriately covered
   with a Marginal Risk given the likely low coverage of the severe
   threat.

   Across southern Texas, the Marginal Risk removed across the upper
   Texas Coast region to mainly encompass the area from Corpus Christi
   to Brownsville westward. The northern extent of the Marginal Risk
   continues along the Rio Grande into Big Bend. Damaging wind risk
   will continue across south Texas through the afternoon before
   redevelopment is expected across Mexico through the evening. This
   secondary round of convection will pose a risk for damaging wind and
   large hail.

   ..Thornton/Smith.. 03/27/2025

   .PREV DISCUSSION... /ISSUED 1128 AM CDT Thu Mar 27 2025/

   ...Central Plains to Lower Missouri/Middle Mississippi Valleys...
   Scattered thunderstorms, including a few lingering strong storms,
   continue late this morning from eastern KS into northern MO within a
   warm-air advection regime.  Morning raob data over the central Great
   Plains indicated the northeastern periphery of the EML is located
   over the lower MO Valley.  Strong heating in wake of the early day
   convection will result in moderate buoyancy developing into
   northeastern KS later this afternoon.  Models show a flattening mid-
   to upper-level ridge through tonight.  Nebulous/weak forcing at best
   is expected in the vicinity of a warm front/outflow intersection
   later this afternoon.  However, the erosion of CINH may enable a few
   isolated thunderstorms to develop late this afternoon into the
   evening.  Recent HRRR runs and the 12 UTC model-run members of the
   HREF show a dearth of storm development.  Confidence in appreciable
   storm coverage is lowering for diurnally based storm initiation and
   casting uncertainty in terms of the potential severe threat. 
   Nonetheless, supercellular development could occur in the presence
   of moderate instability and favorable wind profiles featuring around
   35-40 kt effective shear magnitudes.  A greater coverage of elevated
   storms may occur tonight as the low-level jet reestablishes and
   storms expand eastward regionally. Large hail is the most probable
   hazard in both regimes.

   ...South Texas...
   Visible-satellite imagery shows an extensive cloud shield and
   convective cloud debris across much of south TX into the upper
   coast, and farther west into the Big Bend region.  This is in
   response to a slow-moving upper trough which is forecast to move
   across northern Mexico toward Deep South Texas by Friday morning. 
   This episodic convection across northern Mexico into adjacent
   portions of TX should limit heating during the day.  Forecast
   soundings show seasonably moist profiles from the surface through
   the mid levels subduing lapse rate magnitudes.  Mid-level flow will
   translate through the base of the trough, south of the international
   border into the lower Valley of Texas by early evening.  However,
   considerably weaker flow with north extent (i.e., Edwards Plateau)
   and uncertainty regarding destabilization farther north cast
   uncertainty on storm intensity across south-central TX.  The
   low-level jet will remain focused across south Texas aiding in
   regenerative storm development and an occasional isolated severe
   threat may occur with the stronger storms.

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