Aug 17, 2006 0800 UTC Day 2 Convective Outlook
Updated: Thu Aug 17 06:05:37 UTC 2006
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20060817 0800 UTC Day 2 Outlook Graphic
Probabilistic Graphic
20060817 0800 UTC Day Probabilitic Graphic
   SPC AC 170604
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0104 AM CDT THU AUG 17 2006
   
   VALID 181200Z - 191200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE DAKOTAS AND
   NERN NEB...
   
   ...SYNOPSIS...
   UPPER TROUGH CURRENTLY MOVING INTO THE INTERIOR NORTHWEST WILL BRING
   MODEST MID LEVEL HEIGHT FALLS FROM THE NRN PLAINS TO UPPER MS VALLEY
   THROUGH EARLY SATURDAY. THIS DISTURBANCE WILL CONTINUE TO DAMPEN THE
   NRN PERIPHERY OF THE LARGE UPPER HIGH BLANKETING MUCH OF THE CNTRL
   AND SRN U.S...AND WILL INDUCE FRONTAL WAVE DEVELOPMENT ACROSS SD
   FRIDAY AFTERNOON. COLD FRONT ACCOMPANYING UPPER TROUGH AND
   ASSOCIATED SURFACE WAVE WILL SPREAD SOUTH ACROSS THE CNTRL PLAINS
   THROUGH FRIDAY NIGHT AS UPPER TROUGH AND SURFACE LOW TRACK GENERALLY
   EAST TOWARD THE UPPER MS VALLEY.
   
   NAM-WRF AND GFS MODELS DIFFER SLIGHTLY ON THE TIMING OF THE NRN
   STREAM FEATURES WITH THE GFS INDICATING A FASTER EWD/SEWD MOVEMENT
   TO THE UPPER TROUGH AND COLD FRONT THROUGH EARLY SATURDAY. THIS
   OUTLOOK IS FURTHER COMPLICATED BY A SERIES OF MORE SUBTLE
   SUBTROPICAL SRN STREAM DISTURBANCES IN WEAKER FLOW AROUND THE NRN
   EDGE OF THE DEEP-LAYER ANTICYCLONE. A LEADING FEATURE IN THIS WAVE
   TRAIN WAS ALREADY AIDING MESOSCALE CONVECTIVE COMPLEX OVER THE MO
   VALLEY ATTM. ADDITIONAL IMPULSES ARE FORECAST TO EVOLVE AND EMANATE
   FROM HIGH PLAINS CONVECTION OVER THE NEXT DAY OR SO. THESE WEAK
   DISTURBANCES WILL SPREAD EAST AND ENHANCE ASCENT ATOP A
   QUASI-STATIONARY WARM FRONT FROM MO/IA...ACROSS THE MIDWEST...TO THE
   OH VALLEY THROUGH EARLY SATURDAY.
   
   ...DAKOTAS/NEB...
   STRONGER FORCING ASSOCIATED WITH UPPER TROUGH AND COLD FRONT WILL
   SPREAD ESEWD OVER THE NRN PLAINS DURING THE DAY AND ENHANCE LIFT
   ACROSS INCREASINGLY UNSTABLE AIR MASS. MODELS APPEAR TO BE
   OVERFORECASTING LOW LEVEL MOISTURE ACROSS THE AREA BUT MLCAPE VALUES
   TO 2000 J/KG APPEAR POSSIBLE OVER NEB/SD GIVEN MID TO UPPER 60S
   DEWPOINTS AND TEMPERATURES IN THE 80S TO 90S. SUFFICIENT SHEAR AND
   INSTABILITY ARE FORECAST ACROSS SERN ND AND SD FOR SUPERCELLS WITH
   HAIL. TORNADO POTENTIAL MAY INCREASE SHOULD THIS CONVECTION REMAIN
   DISCRETE AND PERSIST NEAR SURFACE WAVE.
   
   ACROSS NEB...SHEAR WILL INITIALLY BE WEAKER BUT POTENTIAL
   INSTABILITY IS FORECAST TO BE GREATER. HEATING AND LARGE SCALE LIFT
   WILL ACT TO OVERCOME THE CAP ACROSS THIS AREA AND SHOULD RESULT IN
   SCATTERED TSTM DEVELOPMENT THROUGH EVENING. ROBUST MULTICELL
   CONVECTION SHOULD POSE SOME THREAT OF LARGE HAIL AND LOCAL DOWNBURST
   WINDS BEFORE COLD FRONT MOVES ACROSS THE REGION OVERNIGHT.
   
   ...MO/IA EAST TO OH VALLEY...
   AN MCS OR TWO MAY BE ONGOING AT THE START OF THE PERIOD WITHIN
   PLAINS WARM CONVEYOR BELT FROM MO VALLEY EAST ACROSS THE MS VALLEY.
   CONVECTION MAY REGENERATE OR CONTINUE TO SPREAD EAST ACROSS THE
   MIDWEST THROUGH THE DAY SUSTAINED BY MCVS/SHORT WAVE TROUGHS AND
   PERSISTENT WARM AIR ADVECTION ON THE EDGE OF THE STRONGER CAP.
   POCKETS OF GREATER MID LEVEL FLOW ASSOCIATED WITH MCVS/SUBTLE SHORT
   WAVES...COUPLED WITH AREAS OF STRONGER DESTABILIZATION...COULD
   SUPPORT CLUSTERS OF SEVERE STORMS WITH WIND AND HAIL. UNCERTAINTIES
   WITH RESPECT TO TIMING AND AMPLITUDE OF MID LEVEL IMPULSES...CAP
   STRENGTH...LOCATION OF MCS OUTFLOW...AND STRENGTH OF SHEAR...ALL
   PLAY INTO KEEPING SEVERE PROBABILITIES LOW AT THIS TIME.
   
   ..CARBIN.. 08/17/2006
   
   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z