DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 091632
SWODY1
SPC AC 091629

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT SUN JUN 09 2013

VALID 091630Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE LWR TO MID MS
VLYS...

...THERE IS A SLGT RISK OF SVR TSTMS ...

...SYNOPSIS...
LWR MO VLY TROUGH EXPECTED TO CONTINUE ESE AND EVOLVE INTO A CLOSED
LOW CENTERED OVER CNTRL IL BY 12Z MON AS GRT BASIN RIDGE PROGRESSES
E TO THE RCKYS. SATELLITE ALSO SHOWS A SERIES OF WEAK DISTURBANCES
MOVING E OR NE FROM THE WRN/CNTRL GULF CST REGION INTO THE TN
VLY/CAROLINAS.

LOW-LVL MOISTURE WILL CONTINUE TO SPREAD NWD INTO THE TN AND LWR OH
VLYS AHEAD OF SFC LOW ATTENDANT TO MO VLY TROUGH. COUPLED WITH SFC
HEATING AND RELATIVELY COOL MID-LVL TEMPS...THE MOISTENING SHOULD
SUPPORT WIDESPREAD DIURNALLY-ENHANCED SHOWER/TSTM DEVELOPMENT OVER A
LARGE PART OF THE EAST CENTRAL AND SERN U.S. ISOLD SVR WIND GUSTS
AND MARGINALLY SVR HAIL MAY ACCOMPANY MUCH OF THIS ACTIVITY
FOLLOWING MAX HEATING. OTHERWISE...THE POTENTIAL FOR SVR TSTMS
SHOULD BE MOST CONCENTRATED IN AN ARC FROM CNTRL IL/ERN MO SWD INTO
ERN AR/WRN MS...IN ZONE OF STRONGEST ASCENT AHEAD OF MO VLY TROUGH.
A CONDITIONAL RISK FOR SVR STORMS ALSO WILL EXIST IN WEAK UPSLOPE
ENVIRONMENT OVER THE SRN HIGH PLNS.

...MID/LWR MS VLY THIS AFTN THROUGH EARLY TNGT...
WEAK COLD FRONT/WIND SHIFT ASSOCIATED WITH MO VLY UPR TROUGH WILL
ONCE AGAIN SERVE TO FOCUS DIURNALLY-ENHANCED STORM DEVELOPMENT AS
LOBE OF ASCENT OVERSPREADS REGION ON SE SIDE OF THE TROUGH. MID-LVL
LAPSE RATES WILL REMAIN COMPARATIVELY MODEST...BUT SFC HEATING AND
MOISTURE INFLOW SHOW BOOST SBCAPE TO AROUND 1500 J/KG...ESPECIALLY
FROM CNTRL IL SWD INTO ERN AR/WRN MS/NRN LA. COMBINATION OF WEAK
CIN...30-35 KT SWLY DEEP SHEAR...AND SSW-NNE BOUNDARY ORIENTATION
SUGGEST LIKELIHOOD FOR CLUSTERS/BANDS OF SUSTAINED
STORMS...INCLUDING A FEW EMBEDDED SUPERCELLS....WITH LEWP/BOW
STRUCTURES CAPABLE OF SVR WIND/HAIL THROUGH EARLY TNGT. ALTHOUGH A
TORNADO OR TWO CANNOT BE RULED OUT...MODEST LOW-LVL
SPEED/DIRECTIONAL SHEAR SHOULD MINIMIZE SUCH A THREAT.

...TN VLY/SRN APPALACHIANS THIS AFTN...
SATELLITE AND UPR AIR ANALYSES SHOW A SERIES OF DISTURBANCES MOVING
GENERALLY NEWD INTO SW FLOW AHEAD OF MO VLY TROUGH. THE MOST
IDENTIFIABLE SUCH FEATURE APPEARS ATTM TO EXTEND FROM MIDDLE TN SEWD
INTO GA. ASCENT AHEAD OF THIS DISTURBANCE...ALONG WITH SFC HEATING
AND CONTINUED MOISTURE INFLOW...SUGGEST POTENTIAL FOR A FEW CLUSTERS
OF STRONGER STORMS THROUGH THE AFTN /REF MCD 1005/. THESE COULD
PRODUCE LOCALLY DMGG WIND AND PERHAPS MARGINALLY SVR HAIL GIVEN
PRESENCE OF RELATIVELY COOL AIR ALOFT AND BELT OF ENHANCED SWLY FLOW
/25-30 KTS AT 700 MB/ AHEAD OF THE IMPULSE.

...ERN NM/W TX LATE THIS AFTN/EARLY TNGT...
A CONDITIONAL RISK FOR SVR TSTMS WILL EXIST OVER THE SRN HIGH PLNS
LATER TODAY...WHERE A POOL OF BOUNDARY LAYER MOISTURE WILL PERSIST
INVOF OF WEAK FRONT THAT HAS STALLED OVER THE REGION. UPR-LVL
FORCING FOR ASCENT WILL AT BEST BE NEUTRAL. BUT
WEAK...DIURNALLY-ENHANCED UPSLOPE FLOW IN THE PRESENCE OF AMPLE
MOISTURE...STEEP LOW TO MID-LVL LAPSE RATES...AND STRONG SFC HEATING
MAY YIELD ISOLD TO WDLY SCTD TSTMS. WITH 15-20 KT SELY NEAR-SFC FLOW
VEERING TO 25-30 KT NNWLY WINDS AT MID AND UPR LVLS...SETUP COULD
YIELD A SUPERCELL OR TWO WITH SVR HAIL/WIND.

..CORFIDI/SMITH.. 06/09/2013

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