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Day 4-8 Severe Weather Outlook Issued on Dec 30, 2017
Updated: Sat Dec 30 08:02:02 UTC 2017
Day 4-8 Severe Weather Outlook Graphics Issued on Dec 30, 2017
Day 4 Severe Weather Outlook Graphics Issued on Dec 30, 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 30, 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 30, 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 30, 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 30, 2017
Day 8 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
D4Tue, Jan 02, 2018 - Wed, Jan 03, 2018 D7Fri, Jan 05, 2018 - Sat, Jan 06, 2018
D5Wed, Jan 03, 2018 - Thu, Jan 04, 2018 D8Sat, Jan 06, 2018 - Sun, Jan 07, 2018
D6Thu, Jan 04, 2018 - Fri, Jan 05, 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

   ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 300800
   SPC AC 300800

   Day 4-8 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0200 AM CST Sat Dec 30 2017

   Valid 021200Z - 071200Z

   ...DISCUSSION...
   Medium range guidance still indicates that considerable upper trough
   amplification, associated with several digging and consolidating
   short wave perturbations, is possible across the eastern U.S. during
   the middle to latter portion of the coming week.  It appears that
   this could support significant surface cyclogenesis over the western
   Atlantic, which may commence by early Wednesday, most likely
   east/southeast of the southern Florida Peninsula (in the vicinity of
   the Bahamas).  While this may be accompanied by some increase in
   convective potential near southeast Florida coastal areas Tuesday
   night into early Wednesday, the risk for severe weather currently
   appears negligible.

   Upstream, it does appear that the northeastward accelerating
   remnants of a closed low within the southern branch of split
   westerlies over the eastern Pacific could impact portions of central
   or northern California coastal areas (near/north of San Francisco
   Bay) by late Wednesday.  Accompanied by an influx of moisture from
   the lower latitude eastern Pacific, cooling aloft may contribute to
   potential for thunderstorm development, though it still remains
   unclear whether destabilization will become supportive of an
   appreciable severe weather risk.

   Upper flow developments across the eastern Pacific into North
   America become increasing unclear late in the work week into next
   weekend due to low pattern predictability evident in the model
   output.  However, the potential for any inland migrating short wave
   perturbations to support a substantive increase in convective
   potential to the east of the Rockies seems low, due to the lack of
   sufficient boundary layer modification over the Gulf of Mexico in
   the wake of significant preceding cold intrusions.

   ..Kerr.. 12/30/2017

   CLICK TO GET WUUS48 PTSD48 PRODUCT
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Page last modified: December 30, 2017
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