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Apr 15, 2021 1730 UTC Day 2 Convective Outlook
Updated: Thu Apr 15 17:29:42 UTC 2021 (Print Version | 20210415 1730Z Day 2 shapefile | 20210415 1730Z Day 2 KML)
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 Forecast Discussion
   SPC AC 151729

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 PM CDT Thu Apr 15 2021

   Valid 161200Z - 171200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TX
   INTO SOUTH-CENTRAL LA...

   ...SUMMARY...
   Isolated strong to severe storms capable of hail and gusty winds are
   possible across parts of eastern Texas into southwest Louisiana on
   Friday.

   ...Synopsis...
   The transient, modest Omega pattern which has been traversing the
   CONUS for the last few days is forecast to fully break down on
   Friday. The central ridge will dampen significantly and the western
   upper low will transition to an open wave and move across the
   central Plains. A deep and appreciably positively tilted upper
   trough will persist over much of the western and north-central
   CONUS, extending from central Ontario southwestward to off the
   central CA coast early Saturday. 

   This overall pattern evolution will allow moderate
   southwesterly/westerly flow aloft to continue from northern Mexico
   across the southern Plains and Lower MS Valley. A low-amplitude
   shortwave embedded within this zone of stronger mid-level flow is
   expected to move across northern Mexico and into west TX Friday
   evening through Saturday morning.

   ...Central TX into South-Central LA...
   Antecedent showers and thunderstorms cast some doubt to where the
   surface boundaries will be located early Friday morning but model
   consensus places a low over the Permian Basin. A dryline is forecast
   to extend southward from the low through the Big Bend Region, while
   a warm from extends east-northeastward into north TX and then back
   southeastward towards the Sabine River Valley. Showers and
   thunderstorms will likely be ongoing just north of this warm front
   from south-central OK into east TX. Steep mid-level lapse rates and
   40 to 50 kts of deep-layer vertical shear could result in a few
   stronger storms capable of producing large hail.

   The surface low is expected to move eastward/east-southeastward
   throughout the day as the low-amplitude shortwave trough mentioned
   in the synopsis approaches. Mesoscale ascent in the vicinity of the
   triple point as well as increasing large-scale ascent should result
   in the development of additional thunderstorms throughout the
   afternoon and evening. Buoyancy and vertical shear will remain
   strong enough to support robust updrafts. Expectation is for most of
   the storms to be elevated north of the front, with a resulting
   primary threat for large hail. Some isolated damaging wind gusts
   could also occur, particularly with storms in close proximity to the
   warm front.

   Given the warm temperatures aloft, cloud cover, and strong
   convective inhibition, the potential for surface-based storms along
   the dry line appears low. However, mid to upper 60s dewpoints will
   be in place and only modest heating would be needed to reduce
   convective inhibition enough to expected some development along the
   boundary as it push southeastward. As such, any cloud breaks could
   result in convective initiation. The environment will remain
   supportive of strong to severe storms and some expansion on the 5%
   wind and hail probabilities was made on the western edge of the
   outlook area to account for this conditional potential.

   ..Mosier.. 04/15/2021

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z

        
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Page last modified: April 15, 2021
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