...SYNOPSIS...
TROUGHING WILL PREVAIL OVER THE WRN AND ERN PORTIONS OF THE U.S.
THIS PERIOD...WITH LARGE-SCALE RIDGING IN BETWEEN. WITHIN THE RIDGE
HOWEVER...AN UPPER FEATURE IS FORECAST TO MOVE ACROSS THE NRN PLAINS
VICINITY -- WHICH WILL BE A PRIMARY CONTRIBUTOR TO SEVERE POTENTIAL
THIS PERIOD.

AT THE SURFACE...A LOW WILL ACCOMPANY THIS CENTRAL U.S.
IMPULSE...PROVIDING AMPLE ASCENT FOR CONVECTIVE DEVELOPMENT DURING
THE AFTERNOON AND EVENING HOURS.

...SD EWD ACROSS THE SRN MN/IA VICINITY...
AS THE UPPER VORT MAX CROSSES THE NRN PLAINS VICINITY...AIRMASS
DESTABILIZATION IS FORECAST ACROSS AREAS N AND E OF THE ACCOMPANYING
SURFACE LOW -- PROGGED TO TRACK ACROSS THE NEB VICINITY THROUGH THE
DAY. CAPPING IS FORECAST TO BE A CONCERN ACROSS MUCH OF THE PLAINS
/GIVEN BACKGROUND LARGE-SCALE RIDGING/...BUT MAXIMIZED ASCENT JUST
N/E OF THE LOW AND IN ADVANCE OF THE UPPER FEATURE SHOULD RESULT IN
STORM DEVELOPMENT AS THE AIRMASS DESTABILIZES DURING THE AFTERNOON.
WITH STRONGLY VEERING WIND PROFILES...SHEAR WILL SUPPORT
SUPERCELLS...BUT GIVEN CAPPING ISSUES AND THUS CONCERNS ABOUT STORM
COVERAGE...WILL INITIATE ONLY 15%/SLIGHT RISK ATTM. STORMS MAY
INCREASE IN COVERAGE DURING THE EVENING AS A LOW-LEVEL JET DEVELOPS
-- WITH AN MCS POSSIBLY EVOLVING AND MOVING ACROSS ERN SD/SRN MN/NRN
IA. IF THIS OCCURS...THREAT FOR DAMAGING WINDS AS WELL AS HAIL WILL
LIKELY CONTINUE THROUGH THE EVENING.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0349 AM CDT SUN JUN 09 2013

VALID 121200Z - 171200Z

...DISCUSSION...
MEDIUM-RANGE MODELS ARE IN BROAD/GENERAL AGREEMENT THAT THE UPPER
PATTERN WILL REMAIN CHARACTERIZED BY A LARGE CENTRAL U.S. LONG-WAVE
RIDGE SANDWICHED BETWEEN WRN CONUS AND ERN CONUS TROUGHING THROUGH
THE LATTER STAGES OF THE PERIOD.

DESPITE THE BROAD AGREEMENT HOWEVER...THE MODELS DIFFER WITH RESPECT
TO INDIVIDUAL/SMALL-SCALE FEATURES PROGGED TO EJECT FROM THE WRN
U.S. TROUGH AND PROGRESS ANTICYCLONICALLY EWD ACROSS THE CENTRAL
U.S. AROUND THE NRN FRINGE OF THE LONG-WAVE RIDGE.

THE FIRST OF A SERIES OF SUCH SMALL-SCALE FEATURES IS FORECAST TO BE
CROSSING THE UPPER MIDWEST DAY 4 /WED. 6-12/...WITH SOME SEVERE
POTENTIAL EVIDENT ACROSS PARTS OF THE OH VALLEY REGION. ATTM
HOWEVER...POTENTIAL DOES NOT APPEAR TO WARRANT INTRODUCTION OF A 30%
EQUIVALENT THREAT AREA.