DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 151620
SWODY1
SPC AC 151617

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1117 AM CDT MON OCT 15 2007

VALID 151630Z - 161200Z

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

..SRN PLAINS...
SFC/UPR LOW CENTRAL PLAINS MOVING NEWD INTO IA TONIGHT WITH A
TRAILING COLD FRONT EXTENDING FROM WRN MO/KS BORDER TO NWRN TX.
FRONT WILL MOVE EWD AND WEAKEN AS SURFACE PRESSURE FIELDS ACROSS
CENTRAL/SRN PLAINS GRADUALLY RELAX.

PRE-FRONTAL LINE OF THUNDERSTORMS FROM NERN TX WSWWD TO CENTRAL TX
WILL BE PRIMARY FOCUS FOR SEVERE THREAT THIS FORECAST PERIOD. A
VERY MOIST SLY FLOW CONTINUES TO MOVE INLAND ACROSS S TX AND WILL
PROVIDE SUFFICIENT INSTABILITY WHICH COUPLED WITH 40-50 KT OF DEEP
LAYER SHEAR TO MAINTAIN POTENTIAL FOR THREAT OF DAMAGING WINDS/HAIL
THRU THE AFTERNOON. ADDITIONAL ISOLATED SEVERE IS POSSIBLE ALONG
TRAILING OUTFLOW BOUNDARY INTO CENTRAL TX WHICH INTERSECTS UNSTABLE
SLY FLOW FROM THE WRN GULF.

ALTHOUGH MID LEVEL LAPSE RATES AROUND 6C/KM WILL SOMEWHAT LIMIT
UPDRAFT STRENGTH...MLCAPES IN SRN TX WARM SECTOR BY AFTERNOON TO
2000 J/KG AND PRESENCE OF THE STRONG DEEP LAYER SHEAR WILL SUPPORT
SEVERE POTENTIAL UNTIL EVENING.

BY THIS EVENING THE STRONGER UPPER FLOW ROTATES NEWD AWAY FROM THE
TX WARM SECTOR WHICH ALONG WITH SURFACE STABILIZATION SHOULD END THE
SEVERE CONCERN. THUNDERSTORMS SHOULD GENERALLY REMAIN BELOW SEVERE
LIMITS FURTHER E ACROSS LOWER MS VALLEY WHERE INSTABILITY EXPECTED
TO REMAIN WEAK.

..IA...
SOME HEATING WILL DEVELOP FROM MO NWD INTO IA AHEAD OF FRONT AND LOW
SYSTEM BASED ON THE CLEARING IN DRY SLOT NOTED ON VISIBLE IMAGERY.
MLCAPES TO 500 J/KG AND COOL LAPSE RATES AROUND 7C/KM WILL SUPPORT A
FEW STRONG THUNDERSTORMS BY MID-AFTERNOON INTO IA AND NRN MO.
PRIMARY SEVERE THREAT WILL BE LIMITED TO HAIL IN THE MORE VIGOROUS
UPDRAFTS THIS AFTERNOON AS LOW LEVEL SHEAR REMAINS GENERALLY 10-20KT
AHEAD OF THE RELATIVELY WEAK SURFACE/UPPER LOW.

.HALES/LEVIT.. 10/15/2007

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