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Oct 18, 2017 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Wed Oct 18 04:40:31 UTC 2017 (Print Version | 20171018 0730Z Day 3 shapefile | 20171018 0730Z Day 3 KML)
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 Forecast Discussion
   SPC AC 180440

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1140 PM CDT Tue Oct 17 2017

   Valid 201200Z - 211200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Thunderstorm potential will increase across the south-central US and
   over the upper Mississippi Valley.

   ...Discussion...

   Strong short-wave trough will spread across the northern
   intermountain region Friday into the northern High Plains by 21/12z.
   Height falls ahead of this feature should encourage short-wave
   trough over the southern Plains to eject into the Arklatex region.
   Thunder probabilities will increase ahead of these features from the
   lower Sabine River into the upper MS Valley.

   1) South-central US - Southern-stream short-wave trough will eject
   across NM into the TX South Plains early in the period. This feature
   is expected to aid northward transport of low-level moisture and a
   notable increase in PW from the upper TX coast into central OK where
   values should be on the order of 1.5". Forecast lapse rates are not
   particularly steep ahead of this feature but buoyancy should be more
   than adequate for convection in advance of the trough. Some
   consideration has been given to introduce 5% severe probs due to the
   marked increase in moisture as deep-layer shear will increase ahead
   of the trough such that convection could become sustained in nature.
   If later guidance is more aggressive with buoyancy then severe probs
   may be warranted.

   2) Upper MS Valley - Low-level warm advection will increase across
   the upper MS Valley during the day3 period as LLJ strengthens from
   KS into the Arrowhead of MN. Air mass is initially quite dry across
   this region but sustained moistening should lead to adequate
   instability for weak elevated convection after dark well ahead of a
   sharp cold front that will surge into this region by the end of the
   period.

   ..Darrow.. 10/18/2017

   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z

        
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Page last modified: October 18, 2017
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