Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 
000
ACUS48 KWNS 180900
SWOD48
SPC AC 180859

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CDT SAT MAY 18 2013

VALID 211200Z - 261200Z

...DISCUSSION...
THE MEDIUM RANGE MODELS BEGIN THE DAY 4 TO 8 PERIOD WITH AN
UPPER-LEVEL TROUGH OVER THE CNTRL HIGH PLAINS AND SRN ROCKIES WITH
SOUTHWEST FLOW LOCATED FROM THE SCNTRL STATES NEWD INTO THE GREAT
LAKES REGION. STRONG TO POSSIBLY SEVERE THUNDERSTORM DEVELOPMENT
WILL BE POSSIBLE ON TUESDAY/DAY 4 ALONG A CORRIDOR OF MODERATE
INSTABILITY FROM THE SRN PLAINS EXTENDING NEWD INTO THE MID MS
VALLEY. ON WEDNESDAY/DAY 5...THE MODELS MOVE THE UPPER-LEVEL TROUGH
EWD INTO THE OZARKS WITH A COLD FRONT LOCATED FROM THE OH VALLEY
SWWD INTO THE ARKLATEX. STRONG THUNDERSTORM DEVELOPMENT WILL BE
POSSIBLE WEDNESDAY AND WEDNESDAY NIGHT ALONG AND AHEAD OF THE FRONT.
ON THURSDAY/DAY 6...THE MODELS MAINTAIN REASONABLE AGREEMENT WITH AN
UPPER-LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS AND AN
UPPER-LEVEL TROUGH LOCATED IN THE ERN STATES. THUNDERSTORMS WILL BE
POSSIBLE ALONG THE ERN SEABOARD THURSDAY AFTERNOON AND EVENING WITH
MORE ISOLATED DEVELOPMENT POSSIBLE IN THE SRN PLAINS. MODEL
SOLUTIONS DIVERGE ON FRIDAY/DAY 7 SUGGESTING UNCERTAINTY IS
SUBSTANTIAL AT THAT RANGE.

AT THIS POINT...TUESDAY/DAY 4 AND WEDNESDAY/DAY 5 APPEAR TO HAVE THE
GREATEST CHANCE FOR AN ENHANCED SEVERE THREAT AREA. ON THOSE
DAYS...A POTENTIAL FOR SEVERE STORMS WILL EXIST ACROSS A BROAD
CORRIDOR. MESOSCALE INTERACTIONS WILL PROBABLY BE IMPORTANT AS TO
WHERE THE SEVERE THREAT ENDS UP BECOMING ENHANCED. FOR THAT
REASON...WILL GO PREDICTABILITY TOO LOW FOR THIS OUTLOOK.

..BROYLES.. 05/18/2013
USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.