DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 162000
SWODY1
SPC AC 161958

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CDT SUN JUN 16 2013

VALID 162000Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
PLAINS...

A FEW CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS ISSUANCE. THE
FIRST CHANGE IS TO EXTEND THE 2 PERCENT TORNADO NWWD TO INCLUDE
PARTS OF FAR SW SD WHERE A SUPERCELL IS ONGOING. THIS STORM IS
EXPECTED TO MOVE SSEWD JUST TO THE WEST OF THE STRONGEST INSTABILITY
AND SHOULD HAVE A THREAT FOR VERY LARGE HAIL OVER THE NEXT COUPLE
HOURS. THE GREATEST POTENTIAL FOR HAILSTONES GREATER THAN 2 INCHES
IN DIAMETER SHOULD BE FROM FAR SW SD SSEWD INTO WCNTRL NEB NORTH OF
I-80 WHERE INSTABILITY...DEEP LAYER SHEAR AND LAPSE RATES ARE MOST
FAVORABLE ACCORDING TO OBJECTIVE ANALYSIS. HAVE EXTENDED THE
SIGNIFICANT HAIL PROBABILITY INTO FAR SW SD AND REMOVED IT SOUTH OF
I-80. THE LAST CHANGE TO THE OUTLOOK IS TO ADD PARTS OF FAR SRN
AR...NRN LA AND WCNTRL MS INTO THE 5 PERCENT WIND DAMAGE AND HAIL
PROBABILITIES WHERE A LINE OF STORMS IS ONGOING IN A STRONGLY
UNSTABLE AIRMASS.

..BROYLES.. 06/16/2013

.PREV DISCUSSION... /ISSUED 1129 AM CDT SUN JUN 16 2013/

...NEB TO OK AND THE TX PANHANDLE THROUGH TONIGHT...
THE PRIMARY JET IS LOCATED FROM THE NRN PLAINS TO THE GREAT LAKES
AND NEW ENGLAND...WITH THE PRIMARY ASSOCIATED FRONTAL ZONE FROM THE
LOWER GREAT LAKES WWD TO NEB. S OF THE MAIN JET...LOW-AMPLITUDE
WAVES CONTINUE TO MOVE NEWD FROM THE GREAT BASIN TO THE HIGH
PLAINS...AND THEN ESEWD TOWARD THE MS/OH VALLEYS. ONE SUCH WAVE
APPEARS TO BE MOVING FROM ERN WY TO SW SD/NW NEB AS OF MID
MORNING...AND IS ASSOCIATED WITH A CLUSTER OF ELEVATED STORMS IN A
WEAK WAA REGIME. ONCE THE BOUNDARY LAYER WARMS INTO THE 75-80 F
RANGE TO THE S-SW OF THE ONGOING STORMS...CONVECTIVE INHIBITION WILL
BE LARGELY REMOVED AND THE CONVECTION SHOULD BECOME ROOTED AT THE
SURFACE. SUPERCELLS WITH LARGE HAIL/DAMAGING WINDS ARE EXPECTED
INITIALLY GIVEN EFFECTIVE BULK SHEAR NEAR 50 KT AND MLCAPE OF
2000-3000 J/KG.

UPSCALE GROWTH INTO AN MCS APPEARS LIKELY LATER THIS
AFTERNOON/EVENING AS STORM INTERACTIONS LEAD TO COLD POOL
DEVELOPMENT IN NEB. ADDITIONALLY...A MIDLEVEL MOISTURE SURGE AND
WEAK MIDLEVEL WAVE OVER NW CO COULD BE A PRECURSOR TO RELATIVELY
EARLY CONVECTION THIS AFTERNOON ACROSS NE CO...WHICH WOULD SUPPORT
ADDITIONAL COLD POOL DEVELOPMENT AND EVENTUAL INTERACTIONS WITH THE
NEB CONVECTION. AS THE STORMS GROW UPSCALE...THERE WILL BE AN
INCREASING RISK FOR DAMAGING OUTFLOW WINDS ACROSS SW NEB/NW
KS/EXTREME NE CO THIS AFTERNOON/EVENING. THE DAMAGING WIND RISK
WILL SPREAD SEWD ACROSS WRN KS TOWARD NW OK OVERNIGHT.

FARTHER S INTO OK AND THE TX/OK PANHANDLES...A SEPARATE CLUSTER OF
STORMS COULD FORM THIS AFTERNOON NEAR THE WEAK OUTFLOW BOUNDARY AND
REMNANTS OF OVERNIGHT CONVECTION...AND IN ADVANCE OF ANOTHER WEAK
MIDLEVEL WAVE MOVING EWD FROM EXTREME NE NM/SE CO. THESE STORMS
WILL BE CAPABLE OF PRODUCING AT LEAST ISOLATED DAMAGING WINDS/LARGE
HAIL IN A STEEP LAPSE RATE ENVIRONMENT WITH EFFECTIVE BULK SHEAR
NEAR 35 KT.

...OH VALLEY TO MID ATLANTIC THIS AFTERNOON...
A LOW-AMPLITUDE SPEED MAX IS MOVING EWD OVER THE OH VALLEY TOWARD
THE MID ATLANTIC REGION. WIDESPREAD CLOUDS AND POOR LAPSE
RATES...ALONG WITH RATHER MODEST LOW-LEVEL MOISTURE....WILL LIMIT
BUOYANCY IN THE PRE-FRONTAL WARM SECTOR. THE BETTER CHANCE FOR
STORMS WITH ISOLATED STRONG OUTFLOW WINDS WILL BE ALONG THE SRN
FRINGE OF THE THICKER CLOUDS WHERE SURFACE HEATING IS GREATER...FROM
KY TO VA...WHICH ALSO COINCIDES WITH THE SRN FRONT OF THE STRONGER
MIDLEVEL FLOW.

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