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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Jan 23, 2018
Updated: Tue Jan 23 10:09:02 UTC 2018
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Fri, Jan 26, 2018 - Sat, Jan 27, 2018 D7Mon, Jan 29, 2018 - Tue, Jan 30, 2018
D5Sat, Jan 27, 2018 - Sun, Jan 28, 2018 D8Tue, Jan 30, 2018 - Wed, Jan 31, 2018
D6Sun, Jan 28, 2018 - Mon, Jan 29, 2018 (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 231007
   SPC AC 231007

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0407 AM CST Tue Jan 23 2018

   Valid 261200Z - 311200Z

   The 00Z ECMWF/GFS have great differences in the evolution of the Day
   2/3 Pacific trough as it emerges from the Rockies into the Plains
   and eastward this forecast period.  The GFS maintains greater
   consistency with itself, suggesting this trough will be progressive
   and less amplified, while the latest ECMWF indicated slower eastward
   movement and greater amplification across the eastern Plains and MS
   Valley during the latter half of Day 5/Saturday.  Despite this model
   difference, the ECMWF ensemble suggested large spread with the
   amplitude of the trough as it moves into the lower MS Valley,
   central Gulf coast states and OH/TN Valleys during Day 6/Sunday.  

   ...Day 5/Saturday...
   A strong surface ridge extending westward across the Gulf coast
   states to the lower MS Valley should limit the northward return of
   Gulf moisture.  If the ECMWF were to verify into Saturday, the
   amplifying Pacific trough is expected to remain too far west of any
   moisture return into East TX and the lower MS Valley.  Thus, severe
   potential remains low.

   ...Day 6/Sunday...
   The limited moisture return inland with the ECMWF indicating weak
   instability across the warm sector from the central Gulf coast
   region to the Southeast states would suggest a low potential for
   severe storms.  However, given some indication for a more amplified
   trough moving east through the lower MS Valley to the Southeast
   states, this outlook will indicate a low predictability for severe
   storms Day 6 to early Day 7/Monday.

   ..Peters.. 01/23/2018


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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