Feb 21, 2007 1100 UTC Day 3 Severe Thunderstorm Outlook
Updated: Wed Feb 21 08:21:36 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20070221 1100 UTC Day 3 Outlook Graphic
Probabilistic Graphic
20070221 1100 UTC Day Probabilitic Graphic
   SPC AC 210818
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0218 AM CST WED FEB 21 2007
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NRN
   TX...OK...KS AND CNTRL NEB...
   
   ...GREAT PLAINS...
   AN IMPRESSIVE UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS THE WRN U.S.
   FRIDAY CLOSING OFF OVER THE SCNTRL ROCKIES FRIDAY NIGHT. AHEAD OF
   THE UPPER-LEVEL SYSTEM...A VERY STRONG 70 KT LOW-LEVEL JET WILL
   DEVELOP IN THE SRN PLAINS AND A MOIST AXIS WILL SET UP FROM NW TX
   EXTENDING NWD ACROSS WRN OK INTO WCNTRL KS FRIDAY AFTERNOON. SFC
   DEWPOINTS BY LATE FRIDAY AFTERNOON SHOULD REACH THE 55 TO 58 F RANGE
   ALLOWING FOR POCKETS OF MODERATE INSTABILITY JUST EAST OF A
   WELL-DEFINED DRYLINE. ALTHOUGH PARTS OF THE MOIST AXIS MAY REMAIN
   CAPPED FRIDAY AFTERNOON...SOME THUNDERSTORM ACTIVITY SHOULD INITIATE
   BY LATE AFTERNOON OR EARLY EVENING ON FRIDAY ACROSS WRN OK AND THE
   LOW-ROLLING PLAINS OF NORTHWEST TX. ONCE CONVECTION
   INITIATES...SUPERCELL DEVELOPMENT SHOULD QUICKLY OCCUR DUE TO STRONG
   VERTICAL SHEAR OF 60-70 KT. IN ADDITION...STORM DEVELOPMENT WILL BE
   AIDED BY VERY STRONG DYNAMICS ASSOCIATED WITH THE EXIT REGION OF AN
   EJECTING 100 KT MID-LEVEL JET.
   
   FORECAST SOUNDINGS ACROSS NW TX AND WRN OK LATE FRIDAY AFTERNOON
   SHOW CLASSIC LOADED-GUN TYPE SOUNDINGS WITH 0-3 KM SRH INCREASING TO
   ABOVE 500 M2/S2 DURING THE EVENING. THIS SUGGESTS SUPERCELLS WILL BE
   CAPABLE OF PRODUCING TORNADOES. THIS COMBINED WITH 0-1 KM SHEAR
   VALUES EXCEEDING 30 KT WILL MAKE STRONG TORNADOES A POSSIBILITY
   FRIDAY EVENING...SHOULD STRONG CAPPING BE OVERCOME. VERY LARGE HAIL
   AND WIND DAMAGE WILL ALSO BE POSSIBLE WITH SUPERCELLS THAT DEVELOP.
   A BROKEN LINE OF SUPERCELLS AND/OR BOW ECHOES SHOULD MOVE EWD ACROSS
   WCNTRL KS...CNTRL OK AND NRN TX DURING THE OVERNIGHT PERIOD.
   SQUALL-LINE DEVELOPMENT APPEARS LIKELY AND SEVERE STORMS COULD OCCUR
   AS FAR EAST AS ERN OK/ECNTRL KS/NERN TX LATE IN THE PERIOD. ALSO...A
   FEW SEVERE STORMS COULD OCCUR IN CNTRL NEB BUT THIS WILL DEPEND ON
   THE AMOUNT OF MOISTURE RETURN THAT TAKES PLACE IN THE CNTRL PLAINS
   FRIDAY. IF MOISTURE RETURN ENDS UP BEING STRONGER THAN FORECAST...AN
   UPGRADE MAY BECOME NECESSARY IN LATER OUTLOOKS.
   
   ..BROYLES.. 02/21/2007
   
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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z