(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.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 040845
SPC AC 040845
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0345 AM CDT FRI SEP 04 2015
VALID 071200Z - 121200Z
SRN CANADA/NRN PLAINS TROUGH WILL EJECT INTO ONTARIO/GREAT LAKES
REGION DURING THE DAY4-5 TIME FRAME. ATTENDANT HEIGHT FALLS WILL
SPREAD EAST ALONG THE INTERNATIONAL BORDER WITH WEAK FORCING
EXPECTED TO EXTEND ALONG TRAILING COLD FRONT AS IT SAGS INTO THE MID
MS VALLEY/CNTRL PLAINS. LATEST ECMWF/GFS SUGGEST STRONGEST FLOW
ALOFT WILL REMAIN DISPLACED FROM MORE BUOYANT AIR MASS ALONG THE
TRAILING BOUNDARY INTO THE CNTRL PLAINS. WHILE ROBUST CONVECTION
MAY ULTIMATELY DEVELOP ACROSS THIS REGION...FORECAST SHEAR DOES NOT
SEEM ADEQUATE TO WARRANT 15 PERCENT OR GREATER SEVERE PROBS.
CONVECTION SHOULD GRADUALLY DEVELOP SWD DURING SUBSEQUENT DAYS6-7 AS
FRONT SETTLES INTO THE SRN PLAINS AND LOWER/MID MS VALLEY REGION.
FLOW ALOFT SHOULD PROVE TOO WEAK FOR ORGANIZED SEVERE STORMS.
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