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    Day 2 Outlook >
Apr 21, 2018 0600 UTC Day 1 Convective Outlook
Updated: Sat Apr 21 05:02:49 UTC 2018 (Print Version | 20180421 1200Z Day 1 shapefile | 20180421 1200Z Day 1 KML)
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 Forecast Discussion
   SPC AC 210502

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1202 AM CDT Sat Apr 21 2018

   Valid 211200Z - 221200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION
   OF NORTH CENTRAL THROUGH EAST TEXAS INTO WESTERN LOUISIANA...

   ...SUMMARY...
   A few strong to severe thunderstorms are possible across a portion
   of Texas later today and southwest Louisiana tonight.

   ...Synopsis...

   Upper low situated over the southern Rockies will continue through
   the central and southern Plains today and lower MS Valley tonight.
   Warm front now over the northern Gulf to deep South TX will advance
   northward into central TX through southwest LA, while a cold front
   advances southeast, reaching the TX coast by the end of the period.

   ...Texas through western Louisiana...

   Several vorticity maxima will rotate through the upper low
   circulation as it advances east during the period. However, the
   deeper forcing for ascent accompanying these features will remain
   north of warm sector. A large area of warm-advection rain with
   embedded thunderstorms should be ongoing from a portion of north
   central TX into OK, and this activity will expand east during the
   day. Farther south, destabilization will occur primarily in response
   to theta-e advection as the warm front advances northward toward
   central TX. A secondary area of weak destabilization might occur
   farther west across northwest through west central TX in wake of
   early convection where some boundary layer warming is possible in
   advance of southeast-advancing cold front. MUCAPE in all of these
   areas is expected to remain near or below 500 J/kg. Thunderstorms
   may undergo some intensification this afternoon within corridor of
   destabilization across central TX where the low-level jet intersects
   the warm front. While vertical wind profiles with 40-50 kt effective
   bulk shear would support a conditional risk for some supercell
   structures, tendency will be for storms to move toward cool side of
   boundary after initiation. Additional storms may develop this
   afternoon near the triple point over northwest through west central
   TX as boundary layer destabilizes and a vorticity maxima rotates
   through base of the upper trough enhancing deeper forcing for
   ascent. This activity might pose a risk for marginally severe hail
   and gusty winds. Tendency may be for storms to evolve into
   quasi-linear structures over east TX as cold front advances east
   during the evening and overnight, posing some risk for mainly a few
   strong wind gusts. Primary limiting factor for a more robust severe
   threat is expected to be a marginal thermodynamic environment.

   ..Dial/Gleason.. 04/21/2018

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z

        
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Page last modified: April 21, 2018
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