Jun 4, 2009 1300 UTC Day 1 Convective Outlook
Updated: Thu Jun 4 12:55:14 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20090604 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20090604 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20090604 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20090604 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 041250
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0750 AM CDT THU JUN 04 2009
   
   VALID 041300Z - 051200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CNTRL AND SRN HI
   PLNS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF ORE AND ADJACENT
   STATES...
   
   ...SYNOPSIS...
   LITTLE OVERALL CHANGE EXPECTED ACROSS THE LWR 48 THIS PERIOD AS
   ELONGATED TROUGH PERSISTS OVER S CNTRL/SE CANADA...AND UPR LOW OFF
   THE CA CST EDGES SLOWLY EWD.  STRONG SHORTWAVE IMPULSE NOW OVER SK
   WILL CONTINUE SE INTO NRN MN BY 12Z FRI.  FARTHER S...A SERIES OF
   DISTURBANCES IN WEAKER CYCLONIC FLOW OVER THE CNTRL AND SERN U.S.
   SHOULD EVOLVE INTO A TROUGH OVER MS/AL.  W OF THIS EVOLVING
   SYSTEM...SLIGHT HEIGHT RISES WILL PREVAIL OVER THE CNTRL/SRN HI
   PLNS.
   
   AT THE SFC...COLD FRONT ASSOCIATED WITH SK IMPULSE WILL ACCELERATE
   SE ACROSS THE NRN PLNS/UPR MS VLY...WHILE WEAK SFC LOW NOW OVER
   MS/AL REDEVELOPS SLOWLY E/NE INTO GA AND THE CAROLINAS.  WEAKENING
   COLD FRONT JUST NW OF THE LOW LIKELY WILL BE DRAWN INTO THE
   CIRCULATION OF THE LOW.  THE FRONT WILL MAKE MINIMAL SWD PROGRESSION
   IN VA...BUT WILL MOVE STEADILY ESE ACROSS THE TN VLY/GULF CST
   STATES.
   
   ...CNTRL/SRN HI PLNS...
   A WEAK LEE TROUGH WILL BEGIN TO DEVELOP TODAY OVER THE CNTRL/SRN HI
   PLNS AS EXPANSIVE SFC RIDGE CENTERED OVER THE NRN PLNS/UPR MS VLY
   EDGES ESEWD.  SE FLOW AHEAD OF TROUGH WILL BE OF CONTINENTAL
   ORIGIN...WITH SFC DEWPOINTS ONLY IN THE 40S TO LOW 50S F.  MODERATE
   WNW TO NWLY MID LVL FLOW WILL...HOWEVER...MAINTAIN EML ACROSS
   REGION.  AS A RESULT...STRONG SFC HEATING SHOULD BOOST SBCAPE TO AOA
   1000 J/KG.
   
   DESPITE WEAK HEIGHT RISES...DIFFERENTIAL HEATING/TERRAIN
   CIRCULATIONS SHOULD SUPPORT DEVELOPMENT OF ISOLD TO SCTD AFTN/EVE
   STORMS FROM CNTRL/SE WY S/SE INTO CO...NE NM...AND THE WRN TX
   PANHANDLE.  ALTHOUGH LOW LVL WINDS WILL BE LIGHT...AMPLE DEEP SHEAR
   WILL BE PRESENT FOR SUPERCELLS WITH LARGE HAIL AND LOCALLY DMGG
   WIND.  A LIMITED SVR THREAT MAY CONTINUE INTO LATE TONIGHT OVER NE
   CO...WRN NEB...AND NW KS...WHERE A SMALL CLUSTER OR TWO OF STORMS
   MAY PERSIST IN EXIT REGION OF STRENGTHENING/MOISTENING LLJ.
   
   ...ORE AND PARTS OF ADJACENT STATES...
   DIFFLUENT LEFT EXIT REGION OF PERSISTENT HI-LVL JET STREAK ON ERN
   SIDE OF OFFSHORE LOW WILL RESIDE OVER ORE AND ADJACENT PARTS OF NRN
   CA/WRN ID/SRN WA TODAY.  THIS AREA WILL CONTINUE TO COINCIDE WITH
   MAX PW AXIS...WITH AVERAGE VALUES REMAINING CLOSE TO 1 INCH.  BKN
   CLOUD COVER WILL SOMEWHAT LIMIT SFC HEATING.  BUT SUFFICIENT
   DESTABILIZATION SHOULD OCCUR TO SUPPORT DIURNAL INTENSIFICATION OF
   EXISTING STORMS...AND ADDITIONAL STRONG DEVELOPMENT...BY EARLY AFTN.
    SHEAR PROFILES WILL BE FAVORABLE FOR FORWARD-PROPAGATING
   /NW-DEVELOPING/ LINE SEGMENTS WITH LOCALLY DMGG WIND AND HAIL.  A
   FEW SUPERCELLS COULD ALSO OCCUR BEFORE STORM MERGE INTO BKN
   LINES/CLUSTERS BY EARLY EVE.
   
   ...SERN U.S...
   LEAD IMPULSE ASSOCIATED WITH EVOLVING TROUGH OVER THE GULF CST
   STATES HAS ALREADY MOVED INLAND ACROSS THE WRN FL PANHANDLE/SRN AL. 
   SATELLITE LOOPS SUGGEST THAT OVERALL CIRCULATION WILL CONTINUE TO
   SLOWLY STRENGTHEN TODAY/TONIGHT.  ALTHOUGH ASSOCIATED MID/UPR LVL
   FLOW IS EXPECTED TO REMAIN WEAK...A CURRENT OF ENHANCED...MOIST SWLY
   850 MB FLOW...WITH SPEEDS AROUND 30 KTS...WILL PREVAIL IN WARM
   SECTOR OF MS/AL SFC WAVE.  CLOUDS/SHOWERS LIKELY WILL LIMIT LOW LVL
   LAPSE RATES.  BUT IF SMALL...DISCRETE OR SEMI-DISCRETE SHOWERS/WEAK
   STORMS DO INDEED DEVELOP...A CONDITIONAL THREAT WOULD EXIST FOR A
   BRIEF TORNADO OR TWO FROM NRN FL/GA NE INTO THE CAROLINAS.
   
   FARTHER S...A FEW STRONG AFTN MULTICELLS WITH WET MICROBURSTS COULD
   OCCUR OVER CNTRL FL...IN AREA OF STRONGER SFC HEATING ON SRN FRINGE
   OF UPR CIRCULATION.
   
   ...UPR MS VLY...
   A BAND OR TWO OF VIGOROUS BUT LOW-TOPPED STORMS MAY ACCOMPANY COLD
   FRONT MOVING INTO NE ND/NRN MN LATE TODAY.  ALTHOUGH WIND FIELD WILL
   BE FAVORABLE FOR BOWING SEGMENTS...RELATIVELY WEAK LOW LVL LAPSE
   RATES AND SMALL TEMPERATURE-DEWPOINT SPREADS SUGGEST THAT ANY DMGG
   WIND THREAT WILL REMAIN LOW.
   
   ..CORFIDI/GARNER.. 06/04/2009
   
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