Categorical Graphic
Probabilistic Tornado Graphic
Probabilistic Damaging Wind Graphic
Probabilistic Large Hail Graphic

   SPC AC 211949
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0249 PM CDT THU APR 21 2005
   
   VALID 212000Z - 221200Z
   
   THERE IS A MDT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM MDH 10
   NNW PAH 35 N GLH 25 NW TXK 15 NNW PRX 30 WNW MLC BVO EMP BIE LNK 30
   WNW OMA DSM OTM 15 N ALN MDH.
   
   THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 50 SW
   LFK HDO SJT SPS OKC PNC 30 N CNK 10 SSE GRI 20 NNE BBW 55 SW YKN 45
   W ALO 35 NE MLI 15 E MMO LAF IND BNA 35 ESE GWO 10 WNW MLU 50 SW
   LFK.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 SSE P07 50 ENE BGS
   30 WNW SPS 10 SE HUT EAR BBW MHN PHP ATY RWF JVL SBN CMH MGW MRB MRB
   15 SE SBY ...CONT... 35 E EWN 50 SE CLT 10 S AGS 30 NNE MGR 10 SE
   AQQ ...CONT... 30 NNE BVE 35 SE MCB 15 ESE HEZ 45 SW POE 35 N NIR
   LRD.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 NNW PIE 10 WNW ORL
   45 WNW PBI 30 NNE MIA.
   
   GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 20 SSE SEA YKM 35 SW
   LWS 35 SSW 27U 30 S MQM JAC LND RWL 35 NW VEL SLC 20 WSW TWF 80 SW
   BOI 65 N 4LW EUG 10 ESE AST 20 SSE SEA.
   
   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS SE NEB/SW IA/ERN KS/ERN
   OK/MUCH OF MO AND AR....
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK
   AREA...ACROSS MUCH OF THE ERN PLAINS AND MID/LWR MS VLY....
   
   STRETCHING SHEARING OF GREAT BASIN CIRCULATION CONTINUES...AND
   ASSOCIATED JET STREAK/SHORT WAVE TROUGH HAS DEVELOPED EASTWARD INTO
   THE CENTRAL HIGH PLAINS.  ANOTHER WEAK CIRCULATION IS PROPAGATING
   WESTWARD INTO THE PACIFIC NORTHWEST COAST STATES... AROUND BASE OF
   UPPER RIDGE OVER THE CANADIAN ROCKIES. HOWEVER... PLAINS FEATURE
   WILL BE MOST SIGNIFICANT AS IT CONTRIBUTES TO INCREASING FORCING FOR
   UPWARD VERTICAL MOTION ACROSS THE CENTRAL STATES...WHERE MOIST
   CONVECTIVELY UNSTABLE AIR MASS HAS EVOLVED THE PAST SEVERAL DAYS.  
   
   ...PLAINS/MISSISSIPPI VALLEY...**
   MODELS SUGGEST MID-LEVEL CIRCULATION WILL DEVELOP/DEEPEN ACROSS
   NEBRASKA THROUGH THE REMAINDER OF THE AFTERNOON...BEFORE SYSTEM
   ACCELERATES SOUTHEASTWARD INTO THE LOWER MISSOURI VALLEY
   TONIGHT...AHEAD OF NORTHERN BRANCH SHORT WAVE DIGGING INTO THE UPPER
   MISSISSIPPI VALLEY.
   
   MUCH WEAKER SOUTHERN BRANCH IMPULSE DOWNSTREAM HAS ALREADY WEAKENED
   INHIBITION ACROSS THE LOWER MISSOURI VALLEY AND OZARKS.  VIGOROUS
   CONVECTIVE DEVELOPMENT IS ALREADY ONGOING ACROSS THIS REGION AND
   FURTHER INTENSIFICATION SHOULD OCCUR IN ENVIRONMENT WITH MIXED LAYER
   CAPE IN EXCESS OF 2000 J/KG.  CLUSTER OF STORMS MAY EVOLVE OVER
   SOUTHEAST MISSOURI BY THE EARLY EVENING HOURS...WHEN STRENGTHENING
   WEST NORTHWESTERLY MEAN FLOW FIELDS WILL ENHANCE FORWARD PROPAGATION
   AND MORE WIDESPREAD DAMAGING WIND THREAT.  ACTIVITY COULD PROGRESS
   THROUGH PARTS OF WESTERN KENTUCKY/WESTERN TENNESSEE AND NORTHEAST
   ARKANSAS BEFORE WEAKENING OVERNIGHT.
   
   CONVECTIVE DEVELOPMENT IS ALSO ALREADY ONGOING NEAR CENTRAL NEBRASKA
   SURFACE LOW AND OCCLUDED FRONT/WARM FRONT EXTENDING EAST
   SOUTHEASTWARD ACROSS SOUTHEAST NEBRASKA/NORTH CENTRAL MISSOURI INTO
   THE LOWER OHIO VALLEY. PRIMARY SURFACE LOW SHOULD DEVELOP NEAR DRY
   LINE/FRONT INTERSECTION ACROSS NORTHEAST KANSAS BY LATE
   AFTERNOON...ACCOMPANIED BY RAPID INTENSE CONVECTIVE DEVELOPMENT...
   INCLUDING A FEW SUPERCELLS.  VERY LARGE HAIL/DAMAGING WIND GUSTS AND
   ISOLATED TORNADOES ARE LIKELY WITH THIS ACTIVITY...WHICH MAY PERSIST
   MUCH OF THE EVENING...SPREADING EASTWARD ALONG FRONT INTO NORTH
   CENTRAL MISSOURI.
   
   IN THE MEANTIME...WIDELY SCATTERED CONVECTIVE DEVELOPMENT IS
   EXPECTED LATE THIS AFTERNOON ALONG DRYLINE TRAILING SOUTHWARD ACROSS
   SOUTHEAST KANSAS AND EASTERN OKLAHOMA INTO CENTRAL TEXAS. 
   SUPERCELLS ARE POSSIBLE...WITH VERY LARGE HAIL PRIMARY SEVERE
   WEATHER POTENTIAL...BUT DAMAGING WIND GUSTS/ISOLATED TORNADOES WILL
   ALSO BE POSSIBLE.  MORE NOTABLE INCREASE IN COVERAGE IS NOT EXPECTED
   UNTIL CENTRAL PLAINS UPPER LOW/TOUGH BEGINS TO ACCELERATE
   SOUTHEASTWARD DURING THE EVENING HOURS.  CONVECTION MAY EVOLVE INTO
   EXTENSIVE BROKEN SQUALL LINE...WHICH MAY BE ACCOMPANIED BY DAMAGING
   WINDS/HAIL THROUGH MUCH OF THE OVERNIGHT HOURS AS IT PROGRESSES
   TOWARD THE LOWER MISSISSIPPI VALLEY.
   
   ...EASTERN GULF/MID ATLANTIC COAST STATES...** 
   
   **FOR MORE SPECIFIC INFORMATION CONCERNING ONGOING OR IMMINENT
   CONVECTIVE THREATS...PLEASE REFER TO LATEST SPC MESOSCALE CONVECTIVE
   DISCUSSIONS.
   
   ..KERR.. 04/21/2005
   
   ...NOTICE...
   THE STATION RELATIVE POINTS IN THIS PRODUCT ARE NOW AVAILABLE
   SEPARATELY UNDER THE WMO HEADINGS WUUS01 PTSDY1...
   WUUS02 PTSDY2...WUUS03 PTSDY3.  THE INCLUSION OF POINTS
   IN THIS DISCUSSION WILL BE DISCONTINUED AFTER THE 2005
   CONVECTIVE SEASON.  A PUBLIC NOTIFICATION STATEMENT (PNS)
   WILL PROVIDE DETAILS ON THE TRANSITION.
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z