DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081632
SWODY1
SPC AC 081630

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1130 AM CDT SAT JUN 08 2013

VALID 081630Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND SRN
PLNS...

...SYNOPSIS...
WY SHORTWAVE TROUGH WILL FURTHER AMPLIFY SEWD INTO THE CNTRL PLNS
THIS EVE AND INTO THE LWR MO VLY TNGT/EARLY SUN AS A FLAT RIDGE
PERSISTS OVER THE WRN GRT BASIN/PACIFIC NW. FARTHER E...MODERATE SW
TO WSW FLOW WILL PREVAIL OVER THE S CNTRL AND ERN U.S...WITH
SHORTWAVE TROUGH OVER VA/NC.

THE WY TROUGH WILL MAINTAIN WEAK CYCLOGENESIS OVER NEB TODAY...WITH
THE LOW REACHING WRN IA EARLY SUN. THE ATTENDANT COLD FRONT SHOULD
ACCELERATE SSE ACROSS THE CNTRL HIGH PLNS TODAY...AND MORE SLOWLY
E/SE ACROSS THE CNTRL PLNS/MID-MO VLY BY THROUGH TNGT. FARTHER
S...LEE TROUGH/DRY LINE SHOULD MIX E INTO SW KS...THE OK-TX
PANHANDLES...AND SW TX BY LATE AFTN.

THE PLNS SHORTWAVE TROUGH WILL BE THE MAIN FOCUS FOR STRONG/SVR
TSTMS THIS PERIOD...ALTHOUGH A LIMITED SVR POTENTIAL ALSO WILL
ACCOMPANY VA/NC IMPULSE.

...CNTRL/SRN PLNS THIS AFTN/EVE...
AMPLIFYING UPR SYSTEM WILL PROVIDE FAVORABLE WIND FIELD AND
LARGE-SCALE ASCENT FOR SVR TSTMS OVER A LARGE PART OF THE CNTRL PLNS
AND NWRN PARTS OF THE SRN PLNS THIS PERIOD...BUT EXTENT AND
INTENSITY OF ASSOCIATED THREAT WILL BE LIMITED BY MODEST MOISTURE
AVAILABILITY.

SCTD...MAINLY ELEVATED TSTMS SHOULD CONTINUE TO MOVE/DEVELOP E
ACROSS CNTRL/ERN NEB TODAY...IN ZONE OF DCVA/WAA AHEAD OF MAIN UPR
VORT. THIS ACTIVITY MAY EVOLVE INTO A BAND OR TWO OF SUSTAINED
STORMS/EMBEDDED SUPERCELLS WITH A THREAT FOR SVR WIND/MARGINALLY SVR
HAIL...ESPECIALLY IN CNTRL NEB WHERE THE GREATEST BUOYANCY SHOULD
EXIST.

A SOMEWHAT MORE SUBSTANTIAL WIND/HAIL THREAT MAY DEVELOP THIS AFTN
THROUGH EARLY TNGT FARTHER SW ACROSS A LARGE PART OF KS INTO THE
OK-TX PANHANDLES...WRN OK AND W TX. SFC HEATING ALONG KS COLD
FRONT...AND ALONG DRY LINE FARTHER S...SHOULD YIELD SBCAPE AOA
1500-2000 J/KG...WITH AVERAGE SFC DEWPOINTS IN THE UPR 50S TO AROUND
60 F.

WHILE THE STRONGEST MID/UPR-LVL WINDS WITH THE UPR TROUGH WILL
REMAIN WELL W AND N OF WARM SECTOR...AMPLE DEEP SHEAR /WITH
CONSIDERABLE DIRECTIONAL VEERING/...WILL EXIST FOR SUPERCELLS. THE
TORNADO THREAT REMAINS UNCERTAIN. LOW-LVL DIRECTIONAL SHEAR WILL BE
MAXIMIZED NEAR 30-40 KT SLY LLJ OVER CNTRL/NE KS...BUT MID/UPR-LVL
FLOW OVER THAT REGION WILL BE RELATIVELY WEAK. IN CONTRAST...ALONG
THE DRY LINE...LOW-LVL TURNING WILL REMAIN MINIMAL UNTIL THE LLJ
STRENGTHENS TNGT...ALTHOUGH COMPARATIVELY STRONGER MID/UPR FLOW WILL
EXIST FOR MORE SUSTAINED UPDRAFTS.
IN ANY CASE...SIZABLE TEMP-DEWPOINT SPREADS SUGGEST LIKELIHOOD FOR
SUBSTANTIAL STORM OUTFLOW AND EVOLUTION INTO LINES THAT POSE MAINLY
A WIND/HAIL THREAT.

...ERN NC/SE VA THIS AFTN...
VA/NC SHORTWAVE IMPULSE WILL CONTINUE STEADILY NEWD...MOVING OFF THE
MID ATLANTIC CST BY EARLY TNGT. IN THE MEAN TIME...SFC HEATING AND
ASCENT WITH IMPULSE SHOULD FOSTER INCREASING TSTMS IN ASSOCIATED
AXIS OF LOW-LVL CONFLUENCE. WHILE REGION HAS SOMEWHAT DRIED SINCE
YESTERDAY...A RESIDUAL BELT OF MODERATE PW /AROUND 1.50 INCHES/ WILL
REMAIN IN PLACE IN WAKE OF TS ANDREA. COUPLED WITH 30-40
KT...UNIDIRECTIONAL...WSWLY LOW-MID TROPOSPHERIC FLOW...SETUP MAY
YIELD SCTD STORMS/SHORT LINES WITH MARGINALLY SVR HAIL/WIND.

..CORFIDI/SMITH.. 06/08/2013

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