Mar 19, 2013 1300 UTC Day 1 Convective Outlook
Updated: Tue Mar 19 12:58:34 UTC 2013
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20130319 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20130319 1300 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20130319 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20130319 1300 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 27,608 4,066,393 Austin, TX...Killeen, TX...Round Rock, TX...College Station, TX...Llano, TX...
   SPC AC 191254
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0754 AM CDT TUE MAR 19 2013
   
   VALID 191300Z - 201200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/S TX...
   
   ...SYNOPSIS...
   THROUGH REMAINDER PERIOD...BROAD SWATH OF CYCLONIC FLOW WILL
   CHARACTERIZE UPPER-AIR PATTERN ACROSS ROUGHLY ERN 2/3 OF CONUS...E
   OF PROGRESSIVE SYNOPTIC RIDGE NOW CROSSING PAC COAST.  BY
   20/12Z...THIS RIDGE SHOULD EXTEND FROM AZ-AB.  ANCHORING CYCLONIC
   GYRE NOW CENTERED OVER LS AREA SHOULD MEANDER ERRATICALLY NEAR LS
   BEFORE EJECTING ON DAY-2.  WEAK PERTURBATION IS EVIDENT IN MOISTURE
   CHANNEL IMAGERY E OF RIDGE...OVER PORTIONS CENTRAL/SERN NV.  THIS
   FEATURE IS FCST TO MOVE ESEWD ACROSS SRN ROCKIES TODAY...REACHING
   SRN PORTIONS TX PANHANDLE AND ADJOINING SOUTH-PLAINS REGION AROUND
   00Z...THEN LA/LOWER DELTA REGION BY END OF PERIOD. 
   
   AT SFC...COLD FRONT WAS DRAWN AT 11Z FROM WRN SC SWWD ACROSS CENTRAL
   FL PANHANDLE TO N-CENTRAL GULF...BECOMING QUASISTATIONARY OVER NWRN
   GULF OFFSHORE TX/LA TO NEAR BRO.  FRONT AND RELATED THERMAL/THETAE
   GRADIENTS ARE EXPECTED TO BECOME DIFFUSE AND RETREAT NWD SOMEWHAT
   TODAY OVER S TX. 
   
   ...CENTRAL/S TX...
   ISOLATED TO WIDELY SCATTERED TSTMS MAY DEVELOP LATE THIS AFTN OVER
   PORTIONS EDWARDS PLATEAU REGION AND WRN HILL COUNTRY...INITIALLY
   HIGH-BASED WITH POTENTIAL FOR HAIL AND STG TO MRGLLY SVR GUSTS. 
   CONVECTIVE COVERAGE IS FCST TO INCREASE THROUGH EVENING...POSSIBLY
   INCLUDING UPSCALE EXPANSION OF ANY LATE-AFTN ACTIVITY...LEADING TO
   INCREASING COVERAGE/DENSITY OF LARGE HAIL THREAT IN PARTICULAR. 
   MAIN CONTRIBUTING FACTORS FOR RELATED OUTLOOK UPGRADE INCLUDE...
   1. APCHG MID-UPPER SHORTWAVE TROUGH AND RELATED SUBTLE LARGE SCALE
   ASCENT INCREASE MIDLEVEL INSTABILITY AND REINFORCE ALREADY STEEP
   LAPSE RATES ALOFT...
   2. LOW-LEVEL MOISTURE CONTINUES TO INCREASE ALONG AND N OF FRONT IN
   ZONE OF ISENTROPIC ASCENT...MOISTURE TRANSPORT AND ELEVATED WAA...
   3. ISALLOBARIC PROCESSES ON BOTH SIDE OF BOUNDARY LEADING TO
   INCREASING CONVERGENCE AND FRONTOGENETIC FORCING...AND
   4. VERY CONSISTENT TIMING AND GEN MESOSCALE REGION OF TSTM
   DEVELOPMENT AND UPSCALE GROWTH THIS EVENING AMONGST LATEST
   OPERATIONAL PROGS...MAJORITY OF SREF MEMBERS...AND
   CONVECTION-ALLOWING/HIGH-RES GUIDANCE. 
   
   LOW-LEVEL MOIST ADVECTION -- BOTH AT AND ABOVE SFC -- SHOULD BE
   SUFFICIENTLY STRONG TO OFFSET AFTERNOON DIABATIC HEATING/MIXING IN
   SUPPORT OF CONVECTIVE POTENTIAL.  MEANWHILE...VEERING/INCREASING
   FLOW WITH HEIGHT THROUGH MOST OF LOWER-MIDDLE TROPOSPHERE SHOULD
   LEAD TO 50-60 KT EFFECTIVE SHEAR MAGNITUDES...INDICATING POTENTIAL
   FOR SUPERCELLS.  ACTIVITY SHOUDL SHIFT EWD TO ESEWD TOWARD MID-UPPER
   TX COASTAL PLAIN OVERNIGHT...WITH GEN DECREASE IN ORGANIZED SVR
   THREAT INTO SE TX.
   
   ..EDWARDS/ROGERS.. 03/19/2013
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z