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 Sep 25, 2017
Updated: Mon Sep 25 07:52:02 UTC 2017
D4-8 D4 D5 D6 D7 D8
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions

D4Thu, Sep 28, 2017 - Fri, Sep 29, 2017 D7Sun, Oct 01, 2017 - Mon, Oct 02, 2017
D5Fri, Sep 29, 2017 - Sat, Sep 30, 2017 D8Mon, Oct 02, 2017 - Tue, Oct 03, 2017
D6Sat, Sep 30, 2017 - Sun, Oct 01, 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 250750
   SPC AC 250750

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0250 AM CDT Mon Sep 25 2017

   Valid 281200Z - 031200Z

   A shortwave trough will migrate southward across portions of the
   Great Lakes through D4/Thursday and D5/Friday, while a weakening
   cutoff low dissipates across the Intermountain West.  At the
   surface, an expansive ridge will spread a cooler, drier airmass of
   continental origin across much of the central and eastern CONUS,
   with deeper boundary layer moisture confined to Gulf Coast regions
   south of a stationary front in that area.  This overall pattern will
   result in a minimal severe threat through at least D7/Sunday.

   After D7, an active/amplified mid-level pattern across the northern
   tier of the U.S. may interact with returning boundary layer moisture
   on the western periphery of an anticyclone as it shifts toward the
   East Coast.  This pattern may eventually result in a returning
   severe risk to the center of the country beyond the extended
   forecast period although confidence is low.

   ..Cook.. 09/25/2017


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.
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: September 25, 2017
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities