DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 090601
SWODY1
SPC AC 090600

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE APR 09 2013

VALID 091200Z - 101200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL OK...SRN
OK AND NORTH TX...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS...NW AR...MO...SRN IA AND WRN IL...

...SRN AND CNTRL PLAINS...
AN UPPER-LEVEL LOW OVER THE FOUR CORNERS REGION WILL MOVE NEWD INTO
THE CNTRL ROCKIES ON TUESDAY. AT THE SFC...A COLD FRONT WILL ADVANCE
QUICKLY SEWD ACROSS THE SRN HIGH PLAINS AND CNTRL PLAINS. AHEAD OF
THE FRONT...SFC DEWPOINTS SHOULD REACH THE LOWER 60S F ACROSS ERN KS
WITH MID TO UPPER 60S F ACROSS CNTRL OK AND NORTH TX. MODERATE TO
STRONG INSTABILITY IS FORECAST TO DEVELOP ALONG THIS CORRIDOR WITH
CONVECTIVE INITIATION BEGINNING FIRST IN NRN KS DURING THE
MID-AFTERNOON. THUNDERSTORM DEVELOPMENT SHOULD TAKE PLACE ALONG THE
COLD FRONT...QUICKLY EXPANDING SSWWD ACROSS SRN KS AND CNTRL OK
DURING THE LATE AFTERNOON INTO NCNTRL TX BY EARLY EVENING. THE
STRONG INSTABILITY ALONG WITH COUPLED LOW AND MID-LEVEL JETS WILL BE
FAVORABLE FOR A SIGNIFICANT SEVERE WEATHER EVENT FROM LATE TUESDAY
AFTERNOON INTO TUESDAY EVENING.

FORECAST SOUNDINGS AT OKLAHOMA CITY AND WICHITA FALLS AT 00Z/WED
SHOW MLCAPE VALUES OF 2500 TO 3000 J/KG WITH AN IMPRESSIVE SHEAR
ENVIRONMENT. 0-6 KM SHEAR IS FORECAST TO INCREASE DURING THE LATE
AFTERNOON INTO THE 50 TO 60 KT RANGE AS A MID-LEVEL JET MOVES INTO
THE SRN PLAINS. THE SHEAR ALONG WITH MID-LEVEL LAPSE RATES AROUND
8.0 C/KM SHOULD BE FAVORABLE FOR SUPERCELL DEVELOPMENT WITH LARGE
HAIL. THE MORE DOMINANT SUPERCELLS SHOULD BE CAPABLE OF PRODUCING
HAIL GREATER THAN 2 INCHES IN DIAMETER. 0-1 KM SHEAR IS FORECAST TO
INCREASE INTO THE 25 TO 30 KT RANGE DURING THE EARLY EVENING AS THE
LOW-LEVEL JET STRENGTHENS MAKING CONDITIONS FAVORABLE FOR TORNADOES.
A FEW STRONG TORNADOES COULD OCCUR FROM THE OKLAHOMA CITY AREA SSWWD
TO AROUND WICHITA FALLS WHERE THE COMBINATION OF PARAMETERS APPEARS
TO BE MOST IDEAL. ALTHOUGH SOME CONCERN EXISTS ABOUT THE TIMING OF
INITIATION IN SRN OK AND NORTH TX...THE CURRENT THINKING IS THE
THREAT FOR SUPERCELL DEVELOPMENT WILL PERSIST WELL INTO THE EVENING
DUE TO THE STRONG INSTABILITY THAT IS FORECAST.

FURTHER TO THE NORTH FROM ECNTRL KS SWD INTO NERN OK...THE MODELS
APPEAR TO QUICKLY ORGANIZE A LINE OF THUNDERSTORMS ALONG THE FRONT.
THIS SUGGESTS THAT THE POTENTIAL FOR SIGNIFICANT SEVERE MAY BE
SOMEWHAT LESS THERE. HOWEVER...THE LINE SHOULD BE INTENSE WITH
ROTATING CELL ELEMENTS. SEVERE THREAT COVERAGE COULD BE EXTENSIVE
WITH A POTENTIAL FOR LARGE HAIL...WIND DAMAGE AND TORNADOES AS WELL.


...MID-MO VALLEY/MO/SRN IA/WRN IL...
A SHORTWAVE UPPER-LEVEL RIDGE IS FORECAST TO MOVE NNEWD ACROSS THE
UPPER MIDWEST AS AN UPPER-LEVEL LOW MOVES INTO THE CNTRL ROCKIES. A
MID-LEVEL JET TO THE EAST OF THE UPPER-LEVEL SYSTEM IS FORECAST TO
NOSE INTO THE MID-MO VALLEY LATE TUESDAY AFTERNOON. AT THE SFC...A
COLD FRONT WILL ADVANCE SEWD ACROSS SERN NEB WITH A WARM FRONT
EXTENDING EWD NEAR THE IA-MO STATE LINE INTO NCNTRL IL. ALONG AND
SOUTH OF THE WARM FRONT...SFC DEWPOINTS ARE FORECAST TO BE IN THE
LOWER 60S F WITH MODERATE INSTABILITY DEVELOPING BY MID-AFTERNOON. A
LACK OF A CAPPING INVERSION COULD ENABLE THUNDERSTORMS TO DEVELOP
ALONG AND SOUTH OF THE BOUNDARY AROUND MID-DAY WITH A GRADUAL
INCREASE IN CONVECTIVE COVERAGE TAKING PLACE DURING THE AFTERNOON
AND EARLY EVENING.

FORECAST SOUNDINGS AT 00Z/WED FROM NEAR KANSAS CITY EWD TO NEAR
SPRINGFIELD IL SHOW MLCAPE VALUES AROUND 1500 J/KG WITH 40 KT OF 0-6
KM SHEAR. THIS ENVIRONMENT SHOULD SUPPORT SEVERE STORM DEVELOPMENT.
THE MORE DISCRETE CELLS ALONG AND TO THE SOUTH OF THE BOUNDARY WHERE
MODERATE INSTABILITY IS FORECAST...MAY OBTAIN BETTER ORGANIZATION.
ROTATING STORMS AND/OR BOWING LINE-SEGMENTS SHOULD BE CAPABLE OF
PRODUCING ISOLATED LARGE HAIL AND WIND DAMAGE. A FEW TORNADOES COULD
OCCUR WITH THE GREATEST POTENTIAL EXISTING WITH CELLS THAT CROSS THE
WARM FRONT DURING THE EARLY EVENING WHEN LOW-LEVEL FLOW SHOULD
BECOME ENHANCED.

..BROYLES/GARNER.. 04/09/2013

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