(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 030855
SPC AC 030855
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0355 AM CDT MON AUG 03 2015
VALID 061200Z - 111200Z
MODELS CONSENSUS IS THAT A LOW-AMPLITUDE OMEGA BLOCKING PATTERN
SHOULD PERSIST MUCH OF THE 4-8 PERIOD WITH SUBTROPICAL UPPER HIGH
PRESSURE FORECAST TO GRADUALLY SHIFT FROM THE SWRN U.S. INTO THE SRN
PLAINS. FOR DAY 4 /THURSDAY/ A SEVERE-WEATHER THREAT MAY EVOLVE OVER
THE TN VALLEY AS WELL AS FARTHER NORTH ACROSS THE CNTRL/NRN HIGH
PLAINS IN ASSOCIATION WITH A COUPLE OF VORTICITY MAXIMA AND WHERE
POTENTIAL EXISTS FOR THE ATMOSPHERE TO BECOME MODERATELY UNSTABLE.
HOWEVER...LIKELIHOOD OF ONGOING STORMS /ESPECIALLY OVER THE TN
VALLEY REGION/ PRECLUDES INTRODUCTION OF A CATEGORICAL RISK AREA AT
THIS TIME. BEYOND DAY 4 THE SYNOPTIC REGIME WILL PROMOTE EPISODES OF
STRONG TO SEVERE STORMS AND MCS DEVELOPMENT ANYWHERE FROM CNTRL/NRN
PLAINS EWD INTO THE TN VALLEY AREA. PREDICTABILITY REMAINS LOW WITH
THIS PATTERN DUE IN LARGE PART TO POTENTIAL FOR EXTENSIVE ANTECEDENT
CONVECTION WHICH LOWERS CONFIDENCE WHERE THE FOCUS FOR SEVERE
THUNDERSTORM DEVELOPMENT WILL BE ON SUBSEQUENT DAYS.
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