SPC AC 141913

   Day 3 Convective Outlook AMEND 1
   NWS Storm Prediction Center Norman OK
   0113 PM CST Mon Feb 14 2022

   Valid 161200Z - 171200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   NORTH TEXAS INTO CENTRAL AND EASTERN OK AND WESTERN ARKANSAS
   WEDNESDAY NIGHT...

   AMENDED FOR NORTH AND WESTWARD SHIFT IN SEVERE POTENTIAL

   ...SUMMARY...
   Severe thunderstorms are possible Wednesday evening into Thursday
   morning from central Texas and western Oklahoma into portions of
   Arkansas and northwest Louisiana.

   ...19z Day 3 Discussion -- Southern Plains Vicinity...

   The Day 3/Wednesday convective outlook has been adjusted for
   increasing confidence in severe thunderstorm potential further to
   the north and west across parts of TX/OK. Over the last few cycles,
   forecast guidance has trended toward the north/west with
   thunderstorm development. A surface low is forecast to develop
   eastward across the TX Panhandle into western OK Wednesday evening.
   At 00z, a dryline is expected to extend south/southwest across
   western OK into southwest TX, while a cold front extends from
   northwest OK into southeast KS/northwest MO. Boundary-layer moisture
   will be somewhat marginal (surface dewpoints in the 50s F) along the
   surface boundaries, however steep midlevel lapse rates will support
   MLCAPE values as high as 500-750 J/kg. Modestly warm temperatures
   around 850 mb will likely maintain elevated convection, especially
   given northeast storm motion and cells becoming undercut by the
   south/southeastward-advancing cold front.  Nevertheless, forecast
   hodographs indicated enlarged low-level hodographs below 3 km, with
   long, straight hodographs above 3 km, indicative of rotating storms
   capable of severe hail. A low-level jet will increase during the
   evening/overnight hours with strong winds indicated below 1 km,
   which may aid in strong gusts despite the somewhat elevated nature
   of convection. 

   Severe probabilities have been trimmed across parts of the Lower MS
   Valley into central/eastern TX where weaker destabilization and
   capping will limit severe potential through early Thursday morning. 


   ...Previous Day 3 Discussion - Issued 217 am CST...
   A strong southern-stream shortwave trough is forecast to progress
   through the Southwest on Wednesday, before then continuing
   eastward/northeastward through the southern Plains Wednesday evening
   through Thursday morning. A belt of moderate to strong mid-level
   flow will precede this shortwave, stretching from northern Mexico
   northeastward through the Mid MS Valley early Wednesday before
   gradually shifting eastward ahead of the progressing shortwave. 

   Surface cyclogenesis is anticipated over the southern High Plains
   Wednesday afternoon, at the southwestern edge of a cold front
   extending from the Mid MS Valley southwestward into northeastern NM.
   Expectation is for this low to move eastward along the front as it
   surges southward/southeastward. This should bring the low into
   northwest TX late Wednesday evening, eastward along the Red River
   late Wednesday night/early Thursday morning, and northeastward to
   the central OK/AR border by 12Z Thursday. Additionally, strong
   moisture advection is anticipated throughout the day, likely
   bringing 60s dewpoints into east TX ahead of the approaching surface
   low and front. Mid 50s dewpoints will likely reach most of eastern
   OK.

   Thunderstorms will likely begin across western/central OK late
   Wednesday evening, as the front moves into that region amid moderate
   to strong low-level southerly flow. Steep mid-level lapse rates are
   anticipated atop stable low levels and much of this initial activity
   is expected to be elevated north of the front. Even so, steep lapse
   rates and moderately strong mid-level flow could still result in
   thunderstorms strong enough to produce isolated hail. Elevated
   thunderstorm will likely persist throughout the remainder of the
   period in the vicinity of the cold front as it moves southeastward.

   Highest potential for surface-based storms is currently anticipated
   from central TX northeastward into the Arklatex region from
   Wednesday night through early Thursday morning. Storm coverage
   remains in question due to warm mid-level temperatures and resultant
   capping. However, strong low-level southerly winds will support
   robust low-level vertical shear and storm-relative helicity, and
   supercells are possible if updrafts can persist and mature.

   ..Leitman.. 02/14/2022

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