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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Feb 20, 2017
Updated: Mon Feb 20 09:14:03 UTC 2017
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Thu, Feb 23, 2017 - Fri, Feb 24, 2017 D7Sun, Feb 26, 2017 - Mon, Feb 27, 2017
D5Fri, Feb 24, 2017 - Sat, Feb 25, 2017 D8Mon, Feb 27, 2017 - Tue, Feb 28, 2017
D6Sat, Feb 25, 2017 - Sun, Feb 26, 2017 (All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
 Forecast Discussion

   ACUS48 KWNS 200912
   SPC AC 200912

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0312 AM CST Mon Feb 20 2017

   Valid 231200Z - 281200Z

   Medium-range deterministic models continue to show good run-to-run
   consistency in their depiction of a powerful speed max ejecting into
   the Great Plains on Thursday (Day 4) and subsequently moving
   downstream into the OH Valley and southern Great Lakes on Friday
   (Day 5).  A deep surface cyclone will develop northeastward from the
   central Great Plains to the southwestern Great Lakes vicinity on
   Friday.  Models show the advection of an elevated mixed layer and a
   dryline into IL with a cold front eventually overtaking the boundary
   and rapidly surging east-northeast.  This outlook has accounted for
   possible diurnal warm-sector development near the surface low and
   the possibility for a strongly forced squall line posing a risk for
   damaging winds.  Models variability increases by Sunday (Day 7) and
   Monday (Day 8) on the evolution of a possible disturbance moving
   eastward from the southern Great Plains and affecting parts of the
   MS Valley during this timeframe.

   ..Smith.. 02/20/2017


To retrieve previous Day 4-8 convective outlooks, enter the date YYYYMMDD (e.g., 20050310 for March 10, 2005.)
Data available since March 8, 2005.
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Page last modified: February 20, 2017
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