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 |
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Probabilistic Tornado Graphic |
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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 |
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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 |
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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 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z