May 18, 2010 1300 UTC Day 1 Convective Outlook
Updated: Tue May 18 13:00:22 UTC 2010
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20100518 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20100518 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20100518 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20100518 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 181258
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0758 AM CDT TUE MAY 18 2010
   
   VALID 181300Z - 191200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE SRN HI PLNS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HI PLNS INTO SW
   TX...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER DEEP S TX...
   
   ...SYNOPSIS...
   SLOWLY PROGRESSIVE SPLIT FLOW PATTERN WILL CONTINUE OVER THE LWR 48.
    IN THE SRN STREAM...SRN GRT BASIN TROUGH SHOULD MOVE E TO THE SRN
   HI PLNS BY THE END OF THE PERIOD AS OH VLY SYSTEM FURTHER ELONGATES
   AND CONTINUES ENE INTO THE NRN/CNTRL APPALACHIANS. 
   
   AT LWR LVLS...LEE TROUGH EXPECTED TO STRENGTHEN THROUGH
   PERIOD...WITH MAIN SFC CENTER FORMING OVER SE CO TODAY AND ADVANCING
   SLOWLY ESE TO THE OK PANHANDLE EARLY WED.  LOW LVL SSELY FLOW
   WILL...HOWEVER...DEVELOP ALONG THE ENTIRE ERN EXTENT OF THE RCKYS
   FROM NM TO MT.  MEANWHILE...CONVECTIVELY-REINFORCED FRONT NOW OVER
   TX SHOULD REDEVELOP N/NE ACROSS THE SRN PLNS...WITH THE BOUNDARY
   LIKELY TO EXTEND FROM THE TX PANHANDLE SE ALONG THE RED RVR BY 12Z
   WED.  IN THE EAST...WEAK CYCLOGENESIS OFF THE NC CST SHOULD DRIVE
   COMPLEX FRONTAL ZONE SLOWLY SE ACROSS MS/AL/GA AND THE CAROLINAS.
   
   ...CNTRL/SRN HI PLNS THROUGH EARLY WED...
   INCREASING FORCING FOR ASCENT...STRENGTHENING/DIFFLUENT UPR FLOW
   ...LOW LVL MOISTURE RETURN...AND SFC CYCLOGENESIS WILL SUPPORT A
   SUBSTANTIAL SVR POTENTIAL OVER THE CNTRL/SRN HI PLNS TODAY/TONIGHT. 
   STG/SVR TSTMS SHOULD FORM MORE OR LESS SIMULTANEOUSLY IN
   CONFLUENT...MODERATELY UPSLOPE FLOW OVER ERN CO/NE NM...AND ALONG
   N-S DRYLINE NEAR THE NM-TX BORDER.
   
   STEEPENING LOW TO MID LVL LAPSE RATES...MODERATE INSTABILITY AND STG
   VERTICAL SHEAR/VEERING WIND PROFILES WILL BE FAVORABLE FOR 
   SUPERCELLS...WITH LARGE HAIL AND SOME TORNADOES.  THIS THREAT SHOULD
   BE GREATEST LATE THIS AFTN/EARLY TONIGHT OVER SE CO/FAR ERN NM AND
   MUCH OF W TX.  WITH MODERATE SLY LLJ LIKELY TO INCREASE IN RESPONSE
   TO CONTINUED EWD PROGRESSION OF GRT BASIN UPR TROUGH...THE
   RELATIVELY GREATEST TORNADO THREAT A BIT LATER THIS EVE MAY EXIST
   OVER PARTS OF THE TX PANHANDLE AND ADJACENT TX S PLNS...NEAR SFC
   WARM FRONT/CONVECTIVE OUTFLOW/DRY LINE INTERSECTION.
   
   OTHERWISE...THE INCREASING LLJ SHOULD SUPPORT UPSCALE DEVELOPMENT
   INTO ONE OR MORE SE-MOVING MCSS TONIGHT.  WITH EMBEDDED SUPERCELLS
   AND SUSTAINED STORMS/BOWING SEGMENTS...THESE LIKELY WILL YIELD A
   CONTINUED THREAT FOR SVR HAIL...DMGG WIND...AND PERHAPS AN ISOLD
   TORNADO INTO PARTS OF NW TX AND POSSIBLY WRN OK.
   
   ...S TX THROUGH MIDDAY...
   S TX MCS SHOULD CONTINUE SLOWLY ESE THROUGH LATE MORNING...
   SUPPORTED BY MODEST BUT VERY MOIST SELY LOW LVL FLOW BENEATH LIGHT
   WLY FLOW ALOFT.  OTHER STORMS MAY CONTINUE TO FORM ALONG WEAKENING
   W/E OUTFLOW BOUNDARY S OF CRP AND ALONG SEA/LAND BREEZE BOUNDARIES
   NEAR BRO.  CELL MERGERS...HI PW...AND ONSET OF DAYTIME HEATING MAY
   SUPPORT ISOLD LOCALLY DMGG WIND GUSTS...MARGINALLY SVR HAIL...AND
   PERHAPS A BRIEF TORNADO /REF WW 184/.
   
   ...MT AND ADJACENT NORTHERN HIGH PLAINS THIS AFTN/EARLY EVE...
   MOISTURE WILL INCREASE TODAY OVER THE HI PLNS OF ERN MT...WITH PW
   RISING TO AOA .75 INCHES AS LEE SIDE TROUGH STRENGTHENS.  TSTMS
   SHOULD FORM THIS AFTN ALONG THE TROUGH AND/OR ALONG TERRAIN-INDUCED
   CIRCULATIONS AS HEATING BOOSTS SBCAPE TO 500-1000 J/KG /HIGHEST
   ACROSS SE MT/.  COUPLED WITH MODEST...DEEP...S TO SSELY FLOW AND
   STEEP LOW TO MID LVL LAPSE RATES...SETUP MAY SUPPORT A FEW SMALL
   CLUSTERS STG/SVR STMS.  HAIL SHOULD BE THE MAIN THREAT.
   
   ...FL THIS AFTN...
   SLIGHT COOLING/ASCENT WITH CYCLONIC MID/UPR LVL FLOW MAY 
   CONTRIBUTE TO THERMODYNAMIC PROFILES FAVORABLE FOR ISOLD
   STRONG/SVR TSTMS THIS AFTN. A FEW DOWNBURSTS/MARGINALLY
   SVR HAIL WILL BE POSSIBLE...MAINLY ALONG THE E CST SEA BREEZE FRONT.
   
   ..CORFIDI/JEWELL.. 05/18/2010
   
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