Skip Navigation Links 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

< Day 3 Outlook    
Day 4-8 Severe Weather Outlook Issued on Jul 28, 2021
Updated: Wed Jul 28 08:16:03 UTC 2021
D4-8 D4 D5 D6 D7 D8
 Pop.  Cities  CWAs  RFCs  Interstates  Counties  ARTCC  FEMA  Tribal

D4Sat, Jul 31, 2021 - Sun, Aug 01, 2021 D7Tue, Aug 03, 2021 - Wed, Aug 04, 2021
D5Sun, Aug 01, 2021 - Mon, Aug 02, 2021 D8Wed, Aug 04, 2021 - Thu, Aug 05, 2021
D6Mon, Aug 02, 2021 - Tue, Aug 03, 2021 (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 280814
   SPC AC 280814

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0314 AM CDT Wed Jul 28 2021

   Valid 311200Z - 051200Z

   ...Saturday/Day 4 to Monday/Day 6...
   A broad cyclonic flow pattern is forecast this weekend across the
   north-central and northeastern United States. A cold front is
   forecast to move southeastward across the north-central states. On
   Saturday, the front should be located from the central Plains to the
   upper Mississippi Valley. The front is forecast to move to the
   southern Plains and Tennessee Valley by Monday. Thunderstorm
   development will be possible each afternoon and evening along parts
   of the front. Moderate instability and adequate deep-layer shear
   will likely be sufficient for a marginal severe threat, in areas
   where low-level lapse rates become steep. A greater-magnitude severe
   threat will be possible, but this will depend upon the mesoscale
   setup, which is unpredictable at this time.

   ...Tuesday/Day 7 and Wednesday/Day 8...
   The medium-range models move the cold front southward into the Gulf
   Coast states on Tuesday and stall the front near the coast of the
   Gulf of Mexico on Wednesday. Thunderstorms will again be possible
   along and near the front. Instability and deep-layer shear are
   forecast to be strong enough for a marginal wind-damage threat,
   mainly during each afternoon. Mesoscale uncertainty is too high to
   warrant issuing a threat area.

   ..Broyles.. 07/28/2021


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.
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
Page last modified: July 28, 2021
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities