(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 a 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 highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 230955
SPC AC 230955
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0355 AM CST SUN NOV 23 2014
VALID 261200Z - 011200Z
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH A LONGWAVE
TROUGH OVER THE ERN HALF OF THE U.S. ON WEDNESDAY/DAY 4. THE MODELS
MOVE THIS FEATURE EWD ACROSS THE OH AND TN VALLEYS ON WEDNESDAY AS A
COLD FRONT ADVANCES SWD ACROSS SOUTH FL. THUNDERSTORM ACTIVITY WILL
BE POSSIBLE EARLY IN THE DAY ON WEDNESDAY IN FAR SRN FL BEFORE DRIER
AIR MOVES INTO THE AREA. SFC HIGH PRESSURE IS FORECAST TO SETTLE
INTO THE GREAT PLAINS AND MS VALLEY ON THURSDAY/DAY 5 KEEPING A
RELATIVELY DRY AIRMASS LOCATED ACROSS MUCH OF THE CNTRL AND ERN
STATES. AT MID-LEVELS...WEST TO NORTHWEST FLOW BECOMES ESTABLISHED
ACROSS MUCH OF THE CONUS AS AN UPPER-LEVEL TROUGH MOVES ACROSS THE
ERN SEABOARD. THE SFC HIGH IS FORECAST TO MOVE INTO THE ERN U.S. ON
FRIDAY/DAY 6 WHICH MAY ALLOW FOR SFC WINDS TO BECOME SLY IN THE
CNTRL STATES ON FRIDAY AND SATURDAY. THIS SCENARIO WOULD ALLOW FOR
MOISTURE RETURN TO TAKE PLACE ACROSS THE SRN PLAINS ALONG WITH THE
POSSIBILITY OF THUNDERSTORM DEVELOPMENT. ALTHOUGH THE MODELS DO NOT
APPEAR TO DEVELOP CONVECTION LATE IN THE DAY 4 TO 8
PERIOD...UNCERTAINTY REMAINS SUBSTANTIAL THAT FAR OUT. WILL GO WITH
PREDICTABILITY TOO LOW TO ACCOUNT FOR THE OUTSIDE CHANCE FOR STRONG
CONVECTION LATE IN THE DAY 4 TO 8 PERIOD.
CLICK TO GET WUUS48 PTSD48 PRODUCT