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< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Apr 30, 2017
Updated: Sun Apr 30 08:48:03 UTC 2017
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Wed, May 03, 2017 - Thu, May 04, 2017 D7Sat, May 06, 2017 - Sun, May 07, 2017
D5Thu, May 04, 2017 - Fri, May 05, 2017 D8Sun, May 07, 2017 - Mon, May 08, 2017
D6Fri, May 05, 2017 - Sat, May 06, 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 300846
   SPC AC 300846

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0346 AM CDT Sun Apr 30 2017

   Valid 031200Z - 081200Z

   Most of the extended period will generally be characterized by an
   amplifying trough over the central/eastern US, with an upstream
   ridge building over the Rockies. By next weekend,
   ensemble/deterministic guidance indicate the ridge will build
   towards the central US, as another amplified trough moves ashore the
   Pacific Coast.

   ...D4/Wednesday: Portions of Central/Eastern Texas to the Lower
   Mississippi Valley...
   Convection may be ongoing across parts of the Texas Gulf Coast and
   Sabine Valley Wednesday morning, in response to a weak impulse
   within the sub-tropical jet, as well as several areas of enhanced
   warm-air advection. Additionally, guidance is in relatively good
   agreement that storms will form along a cold front pushing southeast
   across Texas during the afternoon/evening. Across eastern Texas,
   early-day convection may stunt considerable destabilization, keeping
   the afternoon/evening severe threat somewhat disorganized. Farther
   west over central/southern Texas, steep mid-level lapse rates may
   offer the potential for stronger storms, but weak/modest
   low/mid-level flow will likely limit updraft organization.
   Considering the aforementioned uncertainties and marginal evolution
   of this system, 15-percent probabilities are not introduced at this
   time. However, at least a Marginal Risk will probably be introduced
   for parts of the region in later outlooks.

   ...D5/Thursday - D6/Friday: Central Gulf Coast to the Carolinas...
   As the trough continues to amplify and evolve eastward towards the
   Atlantic Coast, the warm/moist sector (and any related substantial
   buoyancy) will likely become increasingly displaced from the
   strongest ascent and confined to coastal regions. The relatively
   narrow zone of potentially favorable shear/instability overlap and
   inherent uncertainty at this time range preclude the introduction of
   15-percent probabilities currently.

   ..Picca.. 04/30/2017


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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