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Day 4-8 Severe Weather Outlook Issued on Dec 14, 2017
Updated: Thu Dec 14 10:00:03 UTC 2017
Day 4-8 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 4 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 4 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 5 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 5 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 6 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 6 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 7 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 7 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Day 8 Severe Weather Outlook Graphics Issued on Dec 14, 2017
Day 8 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4Sun, Dec 17, 2017 - Mon, Dec 18, 2017 D7Wed, Dec 20, 2017 - Thu, Dec 21, 2017
D5Mon, Dec 18, 2017 - Tue, Dec 19, 2017 D8Thu, Dec 21, 2017 - Fri, Dec 22, 2017
D6Tue, Dec 19, 2017 - Wed, Dec 20, 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

   ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 140958
   SPC AC 140958

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0358 AM CST Thu Dec 14 2017

   Valid 171200Z - 221200Z

   ...DISCUSSION...
   Medium-range models are in general agreement indicating the Day 3
   Rockies trough will become more positively tilted on Day 4 (Sunday)
   as it shifts east, extending from northwest Mexico and the southwest
   states to the upper MS Valley.  And, consensus exists with an
   amplified upper-air flow pattern across the northern half of the
   United States for Day 5 & 6 (Monday & Tuesday), before the next
   large-scale Pacific trough advances inland in the western U.S. late
   Day 6 and Day 7 (Wednesday).  Meanwhile, model differences exist
   with a midlevel cyclone evolving across the Baja/northwest Mexico
   (per ECMWF) and the southwest states (per GFS), and its
   amplification and eastward movement through the southern Plains and
   Gulf coast states through Day 7 (Wednesday).

   ...Day 4 (Sunday)...
   There will be a potential for thunderstorms across the Gulf coast
   region on Sunday.  However, given the Day 3 TX shortwave trough
   should be weakening and moving northeast away from the Gulf coast,
   the lack of stronger forcing for ascent and weak instability suggest
   any severe-weather potential will be less than 15%.

   ...Beyond Day 4...
   Given model differences with the southern-stream shortwave trough
   and stronger instability remaining across the Gulf Basin, the
   potential for severe-weather will remain less than 15%.

   ..Peters.. 12/14/2017

   CLICK TO GET WUUS48 PTSD48 PRODUCT
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Page last modified: December 14, 2017
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