Jun 6, 2011 0600 UTC Day 1 Convective Outlook
Updated: Mon Jun 6 06:04:08 UTC 2011
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20110606 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20110606 1200 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
20110606 1200 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
20110606 1200 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.
   SPC AC 060600
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT MON JUN 06 2011
   
   VALID 061200Z - 071200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF MT...FAR NRN
   WY...NWRN SD...AND WRN ND...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF WI INTO UPPER
   AND LOWER MI...
   
   ...SYNOPSIS...
   CLOSED MID-UPPER LEVEL LOW CURRENTLY MOVING INLAND ACROSS CENTRAL CA
   PER WATER VAPOR IMAGERY WILL REMAIN PROGRESSIVE AND BECOME
   NEGATIVELY-TILTED AS IT TRACKS NEWD ACROSS THE GREAT BASIN...
   REACHING THE NRN HIGH PLAINS BY 12Z TUESDAY.  THIS EVOLUTION IN THE
   UPPER LEVEL FLOW IN THE WEST WILL SUPPORT AN EWD SHIFT OF THE STRONG
   CENTRAL/SRN PLAINS RIDGE TOWARD THE MID MS VALLEY.  MEANWHILE...WLY
   MID-UPPER LEVEL FLOW WILL PERSIST ACROSS THE NRN TIER STATES TO SRN
   QUEBEC...BETWEEN THE CENTRAL U.S. RIDGE AND A DEEP VORTEX CENTERED
   INVOF HUDSON BAY.
   
   ...MT/WRN DAKOTAS TO PARTS OF THE NRN ROCKIES/NRN GREAT BASIN...
   WHILE A COLD FRONT MOVES SSEWD INTO THE UPPER MS VALLEY/GREAT LAKES
   TODAY...THE WRN EXTENSION OF THIS BOUNDARY SHOULD REMAIN
   QUASI-STATIONARY FROM NRN SD INTO SRN MT.  HEIGHT FALLS SPREADING
   NEWD TOWARD MT TODAY...WITH GREATEST FALLS EXPECTED AFTER
   07/00Z...WILL SUPPORT A DEEPENING LEE LOW MOVING NWD INTO SOUTH
   CENTRAL MT THIS AFTERNOON...AND THEN TRACKING NWD THROUGH ERN MT
   TONIGHT.  ELY LOW LEVEL WINDS WILL ADVECT MOISTURE WWD INTO MT
   BENEATH VERY STEEP LAPSE RATES RESULTING IN A MODERATELY UNSTABLE
   AIR MASS ALONG AND N OF THE W-E ORIENTED SURFACE BOUNDARY.  WEAK
   HEIGHT FALLS INITIALLY THIS AFTERNOON AHEAD OF THE WRN TROUGH AND
   UPSLOPE FLOW WILL PROMOTE TSTM DEVELOPMENT.  STRONGER FORCING IS
   EXPECTED THIS EVENING THROUGH TONIGHT SUPPORTING AN INCREASE IN TSTM
   COVERAGE ACROSS THE REST OF MT INTO PARTS OF WRN ND/NWRN SD.  THE
   DEGREE OF INSTABILITY AND STRONG DEEP LAYER AND LOW LEVEL SHEAR
   SUGGESTS SUPERCELLS WILL BE POSSIBLE WITH A COUPLE OF TORNADOES AND
   VERY LARGE HAIL...ESPECIALLY OVER SRN/SERN MT AS A ESELY LLJ
   STRENGTHENS INTO THE EVENING.
   
   FARTHER W/SW ACROSS THE NRN ROCKIES TO NRN GREAT BASIN...LOW LEVEL
   MOISTURE WILL BE WEAKER.  HOWEVER...STEEP MIDLEVEL LAPSE RATES AND
   SURFACE HEATING WILL CONTRIBUTE TO DESTABILIZATION WITH MARGINAL
   INSTABILITY /MLCAPE AOB 500 J PER KG/ EXPECTED BY PEAK HEATING. 
   FORCING FOR ASCENT SPREADING ACROSS THIS REGION AS THE CA CLOSED LOW
   BECOMES NEGATIVELY-TILTED...TRACKING NEWD...WILL SUPPORT AN INCREASE
   IN TSTM DEVELOPMENT.  EFFECTIVE BULK SHEAR OF 25-35 KT SUGGESTS A
   FEW STORMS COULD BE ORGANIZED...ESPECIALLY ALONG A COLD FRONT
   ADVANCING ACROSS THE NRN GREAT BASIN THIS AFTERNOON.  HOWEVER...WEAK
   INSTABILITY SHOULD LIMIT THE COVERAGE OF STRONGER TO SEVERE
   STORMS...AND THUS WILL MAINTAIN LOW SEVERE WIND/HAIL PROBABILITIES.
   
   ...WI/PARTS OF UPPER MI AND MUCH OF LOWER MI...
   UNCERTAINTY EXISTS WITH THE AMOUNT OF CLOUD COVER THAT MAY BE LEFT
   OVER FROM SUNDAY NIGHT/EARLY MONDAY MORNING CONVECTION ACROSS SERN
   MN INTO WRN WI.  CURRENT RADAR IMAGERY SHOWED TSTMS TRYING TO
   DEVELOP OVER SERN MN.  THIS CLOUD COVER MAY DELAY STRONGER SURFACE
   HEATING THIS MORNING ACROSS THE WARM SECTOR.  DESPITE THIS LIMITING
   FACTOR...MOISTURE ADVECTION /SURFACE DEWPOINTS IN THE UPPER 60S TO
   AROUND 70 F/ APPEAR LIKELY INTO WI AHEAD OF THE COLD FRONT...GIVEN
   THE PRESENCE OF THESE VALUES NOW OVER IA.  THIS COMBINED WITH AN
   EML/STEEP LAPSE RATES SPREADING EWD INTO THE WRN GREAT LAKES SHOULD
   SUPPORT A VERY UNSTABLE WARM SECTOR BY THIS AFTERNOON.
   
   ALTHOUGH LOW LEVEL CONVERGENCE ALONG THE SWD MOVING COLD FRONT WILL
   BE WEAK...MODELS SUGGEST INITIAL STORMS MAY DEVELOP ALONG THE WARM
   FRONT AS IT ADVANCE INTO ERN WI AND EVENTUALLY LOWER MI...WITH
   EVENTUAL DEVELOPMENT ALONG AND AHEAD OF THE COLD FRONT.  STRONGER
   DEEP LAYER SHEAR WITH EWD EXTENT SUGGESTS SUPERCELLS WITH ALL SEVERE
   WEATHER THREATS POSSIBLE SHOULD BE GREATEST FROM CENTRAL/ERN WI INTO
   UPPER AND LOWER MI.  MODELS SUGGEST ONE OR TWO FORWARD PROPAGATING
   MCS MAY EVOLVE ACROSS THE UPPER GREAT LAKES THIS EVENING/TONIGHT AS
   A WLY LLJ STRENGTHENS FROM SRN MN TO LOWER MI.
   
   ...SERN STATES WSWWD ALONG THE GULF COAST REGION...
   SIMILAR TO THE LAST FEW DAYS...SURFACE HEATING WITHIN RICH BOUNDARY
   LAYER MOISTURE WILL SUPPORT A MODERATELY UNSTABLE AIR MASS.  TSTMS
   ARE EXPECTED TO RE-DEVELOP WITHIN THIS ENVIRONMENT TODAY WITH ELY
   LOW-MIDLEVEL WINDS PROMOTING WWD MOVING ACTIVITY.  STEEP LOW LEVEL
   LAPSE RATES AND THE DEGREE OF MOISTURE/INSTABILITY SHOULD SUPPORT
   WET MICROBURSTS...WHILE WEAK DEEP LAYER SHEAR SUGGESTS THE
   LIKELIHOOD FOR PULSE-TYPE STORMS.
   
   ..PETERS/COHEN.. 06/06/2011
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z