May 6, 2007 0600 UTC Day 1 Convective Outlook
Updated: Sun May 6 10:00:26 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the central plains this afternoon and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20070506 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20070506 1200 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20070506 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20070506 1200 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 060557
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1257 AM CDT SUN MAY 06 2007
   
   VALID 061200Z - 071200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF CNTRL/ERN
   KS...NWRN OK AND EXTREME ERN TX PNHDL...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
   PLAINS STATES...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS FL...
   
   ...ERN PARTS OF THE NRN PLAINS SWD INTO THE SRN PLAINS...
   ELEVATED CONVECTION THAT HAS PERSISTED ON THE HIGH PLAINS SATURDAY
   EVE HAS LIKELY CONTRIBUTED TO A NOTABLE OUTFLOW BOUNDARY/FRONT THAT
   HAS NOT BEEN HANDLED BY THE SHORT TERM MODEL SUITE.  HOW THIS WILL
   MODULATE THE SVR PROBABILITIES FOR SUNDAY IS UNCERTAIN.  WHAT IS
   MORE CERTAIN IS THAT THERE WILL BE CONSIDERABLE TSTMS AND
   ATMOSPHERIC OVERTURNING FROM ABOUT SD-NRN NEB NWD THROUGH EARLY
   SUNDAY.  THIS SHOULD SHIFT AND CONFINE THE PRIMARY SVR PROBABILITIES
   SWD WITH THE NRN EXTENT FROM THE ERN NEB AREA SWWD INTO CNTRL KS. 
   FARTHER SW...AFOREMENTIONED FRONT SHOULD DISSOLVE AND LOW-LEVEL
   RECOVERY SHOULD TAKE PLACE AS PRESSURES CONTINUE TO FALL OVER THE
   ROCKIES/HIGH PLAINS.
   
   NOT MUCH CHANGE TO THE OVERALL FLOW REGIME WILL EXIST ON
   SUNDAY...THOUGH THE UPR LVL FLOW WILL TEND TO WEAKEN A BIT OVER
   SATURDAY.  NONETHELESS...THE BOUNDARY LAYER WILL REMAIN QUITE MOIST
   WITH UPR 60S TO NEAR 70 DEG F DEW POINTS IN PLACE OVER MOST OF THE
   CNTRL/SRN PLAINS.  STRONGEST HEATING IS EXPECTED TO TAKE PLACE FROM
   THE LOW ROLLING PLAINS OF W TX NEWD INTO CNTRL KS WITH MLCAPES
   APPROACHING 2500-3000 J/KG BY MID-AFTN.  IT IS DIFFICULT TO RESOLVE
   SUBTLE JET MAXIMA ROUNDING THE WRN TROUGH...BUT HEATING ALONE AND
   WEAK CYCLONIC FLOW ALOFT SHOULD BE SUFFICIENT TO WEAKEN THE CAP. 
   TSTMS WILL EITHER INITIATE ALONG THE TRIPLE POINT/ DRYLINE OR
   STRENGTHEN ALONG EXISTING MORNING CONVECTION FROM CNTRL KS SWWD INTO
   THE ERN TX PNHDL SUNDAY AFTN/EVE.  ROUGHLY 45-50 KTS OF SSWLY
   MIDLEVEL FLOW ATOP SSELY LOW LEVEL FLOW WILL BOOST VERTICAL SHEAR
   FOR SUPERCELLS WITH VERY LARGE HAIL.
   
   FORECAST 2-8 KM SHEAR VECTORS STILL EXHIBIT SUFFICIENT
   CROSS-COMPONENT TO THE INITIATING BOUNDARIES TO SUPPORT DISCRETE
   SUPERCELLS.  RIGHT MOVING CELLS WILL LIKELY ACQUIRE SUFFICIENT
   LOW-LEVEL HELICITY FOR A FEW TORNADOES.  STRONGEST TORNADOES ARE
   EXPECTED FROM PARTS OF ECNTRL...CNTRL AND SCNTRL KS SWWD INTO NWRN
   OK.  ACTIVITY MAY EVOLVE INTO ONE OR MORE LEWPY LINE SEGMENTS SUNDAY
   NIGHT AND MOVE/DEVELOP NEWD TOWARD THE CORN BELT/LWR MO VLY WITH
   ATTENDANT DAMAGING WINDS/HAIL AND ISOLD TORNADOES.
   
   FARTHER S...CAP WILL REMAIN STRONGER ACROSS SWRN TX...THOUGH PERHAPS
   A BIT WEAKER THAN ON SATURDAY.  ISOLD SUPERCELLS WILL BE POSSIBLE
   ALONG THE DRYLINE WITH PRIMARILY LARGE HAIL. OVERNIGHT... SEVERAL
   MODELS INSIST ON TSTMS DEVELOPING OVER SWRN TX AS A SELY LLJ ADVECTS
   MOISTURE BACK WEST DURING THE EVE.  IT IS NOT CERTAIN THIS SCENARIO
   WILL PLAY OUT...BUT WILL MAINTAIN CONDITIONAL THREATS FOR SVR TSTMS
   MAINLY FOR THE LATE AFTN THROUGH MID-EVE HOURS.
   
   ...LWR MO VLY/OZARKS...
   EVE MESOANALYSIS PLACES A NW-SE ORIENTED WARM FRONT FROM THE MO VLY
   SEWD INTO THE OZARKS.  THIS FRONT SHOULD REMAIN IN PLACE THROUGH
   SUNDAY.  AIR MASS ALONG/WEST OF THIS FRONT WILL BECOME QUITE
   UNSTABLE BY AFTN OWING TO MID-UPR 60S SFC DEW POINTS BENEATH STEEP
   LAPSE RATES ALOFT.  THIS WILL CONTRIBUTE TO 2500 J/KG OF MLCAPE. 
   TSTMS ARE LIKELY TO DEVELOP ALONG THE FRONT DURING THE AFTN.  H5
   FLOW WILL REMAIN AROUND 40-45 KTS WITH FAVORABLE VERTICAL SHEAR
   SUFFICIENT FOR SUPERCELLS.  LOW-LEVEL TURNING VCNTY THE FRONT AND
   MOIST BOUNDARY LAYER WILL ALSO BE FAVORABLE FOR A TORNADO OR TWO.
   
   ...FAR NRN PLAINS...
   NRN PORTION OF THE WRN STATES UPR TROUGH WILL CLOSE INTO A LOW AND
   BECOME ABSORBED INTO THE NRN STREAM.  80-85 KT MIDLEVEL JET AND VERY
   STRONG LOW-LEVEL WARM ADVECTION WILL LIKELY DRIVE NUMEROUS TSTMS
   ACROSS THE NRN PLAINS EARLY SUNDAY.  MODELS FORECAST A MID-LEVEL DRY
   SLOT WILL NOSE NWD IN WAKE OF THIS FEATURE ALLOWING SOME RECOVERY
   AND DESTABILIZATION DURING SUNDAY AFTN GIVEN THE MID-MINUS TEENS H5
   TEMPERATURES ATOP RESIDUAL 50S DEW POINTS.  ISOLD TSTMS MAY
   REDEVELOP WITHIN THE DRY SLOT DURING THE AFTN WITH POSSIBLE
   HAIL/HIGH WINDS.  COVERAGE/THREAT APPEARS LESS THAN SLGT RISK ATTM.
   
   ...FL...
   BACKDOOR COLD FRONT WILL SETTLE SWD ACROSS SRN GA AND FL SUNDAY AND
   SUNDAY NIGHT.  AIR MASS AHEAD OF THIS FRONT IS EXPECTED TO BECOME
   UNSTABLE WITH MLCAPES TO 2000 J/KG.  SCT TSTMS WILL DEVELOP ALONG
   THIS COLD FRONT AND IN THE WARM SECTOR ALONG SEABREEZE BOUNDARIES
   DURING THE AFTN.  DEEP NWLY TROPOSPHERIC FLOW OF 35-40 KTS AND
   RELATIVELY COLD TEMPERATURES ALOFT WILL BE FAVORABLE FOR SUPERCELLS
   WITH LARGE HAIL...DAMAGING WINDS AND POSSIBLY AN ISOLD TORNADO.
   
   ..RACY/GRAMS.. 05/06/2007
   
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