SPC AC 020730

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0230 AM CDT WED JUL 02 2014

   VALID 041200Z - 051200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   AN UPSWING IN THUNDERSTORM PROBABILITIES ACROSS PARTS OF THE
   INTERMOUNTAIN WEST AND ROCKIES IS EXPECTED TO CONTINUE ON THE 4TH OF
   JULY.  OTHER SCATTERED THUNDERSTORMS WILL BE POSSIBLE ACROSS THE
   NORTHERN AND CENTRAL PLAINS...WHILE A LINGERING RISK OF
   THUNDERSTORMS CONTINUES ACROSS PARTS OF CENTRAL TEXAS AND THE TEXAS
   COAST...AS WELL AS ACROSS MUCH OF FLORIDA.  STRONG TO SEVERE STORM
   DEVELOPMENT MAY NOT BE OUT OF THE QUESTION ACROSS PARTS OF SOUTH
   DAKOTA INTO NEBRASKA...MAINLY FRIDAY NIGHT...AND ACROSS THE PHOENIX
   METROPOLITAN AREA AND SURROUNDING DESERTS.

   ...SYNOPSIS...
   THE TRANSITION TO A LESS AMPLIFIED UPPER FLOW REGIME APPEARS LIKELY
   TO CONTINUE DURING THIS FORECAST PERIOD.  LINGERING UPPER TROUGHING
   ACROSS THE NORTHEAST IS EXPECTED TO BEGIN PROGRESSING
   OFFSHORE...LIKELY CONTRIBUTING TO THE CONTINUING NORTHEAST
   ACCELERATION OF ARTHUR AWAY FROM SOUTHERN MID ATLANTIC COASTAL
   AREAS.  IN THE WAKE OF THESE FEATURES...COOLER/DRIER LOW-LEVEL AIR
   WILL OVERSPREAD MUCH OF THE REMAINDER OF THE ATLANTIC SEABOARD...
   EXCEPT FOR THE FLORIDA PENINSULA...WHILE LINGERING ACROSS MOST
   REMAINING AREAS EAST OF THE MISSISSIPPI VALLEY.  AT MID
   LEVELS...MODELS SUGGEST THAT RIDGING WITHIN THE WESTERLIES WILL
   CONTINUE TO BROADEN ALONG THE CANADIAN/U.S. BORDER AREA.  AT THE
   SAME TIME...SUBTROPICAL RIDGING MAY REMAIN FAIRLY PROMINENT ACROSS
   THE FOUR CORNERS STATES...WHILE A COUPLE PERTURBATIONS MIGRATING
   AROUND ITS PERIPHERY PERHAPS ENHANCE CONVECTIVE DEVELOPMENT ACROSS
   PARTS OF THE NORTH CENTRAL PLAINS AND THE SOUTHWESTERN DESERTS.

   ...NORTH CENTRAL PLAINS...
   THERE APPEARS A MODEST SIGNAL WITHIN LATEST MODEL DATA THAT A SHORT
   WAVE IMPULSE WILL PROGRESS AROUND THE NORTHEASTERN PERIPHERY OF THE
   SUBTROPICAL HIGH THROUGH PARTS OF SOUTH DAKOTA AND NEBRASKA BY
   FRIDAY EVENING.  ALTHOUGH THERE MAY BE SIGNIFICANT CAPPING
   ASSOCIATED WITH WARM ELEVATED MIXED-LAYER AIR ADVECTING INTO THE
   NORTH CENTRAL PLAINS...ASSOCIATED FORCING MAY WEAKEN INHIBITION TO
   ALLOW FOR CONVECTIVE DEVELOPMENT IN THE PRESENCE OF SIZABLE CAPE
   /2000-3000+ J PER KG/.  ACTIVITY COULD INITIATE NEAR THE BLACK HILLS
   BENEATH WEAK NORTHWESTERLY MID-LEVEL FLOW...BEFORE PROPAGATING
   SOUTHEASTWARD.  IT IS NOT CLEAR WHETHER LATE AFTERNOON ACTIVITY WILL
   PERSIST...BUT A NOCTURNALLY STRENGTHENING LOW-LEVEL JET MAY
   CONTRIBUTE TO AN AREA OF ENHANCED FORCING AND POTENTIAL FOR
   INCREASING CONVECTIVE DEVELOPMENT DURING THE EVENING INTO OVERNIGHT
   HOURS.  IF THIS OCCURS...SEVERE HAIL AND WIND GUSTS WILL PROBABLY
   ACCOMPANY ACTIVITY AS IT DEVELOPS SOUTHEASTWARD.

   ...CENTRAL ARIZONA...
   LOW-LEVEL MOISTURE RETURN IS EXPECTED TO CONTRIBUTE TO INCREASING
   CONVECTIVE POTENTIAL DURING THE NEXT FEW DAYS.  IT IS POSSIBLE
   CONVECTION COULD BE ONGOING EARLY FRIDAY ACROSS THE REGION...BEFORE
   CLEARING OUT DURING THE DAY...WITH STRONG SURFACE HEATING
   CONTRIBUTING TO A HOT...RELATIVELY MOIST BUT DEEPLY MIXED BOUNDARY
   LAYER.  MODELS CURRENTLY SUGGEST ADDITIONAL STORMS ARE POSSIBLE IN
   WAKE OF EARLY DAY ACTIVITY...SOME TIME FRIDAY EVENING...PERHAPS
   INITIATING OFF THE HIGHER TERRAIN OF SOUTHEAST ARIZONA.  FORECAST
   VERTICAL SHEAR PROFILES APPEAR POTENTIALLY FAVORABLE FOR THE
   EVOLUTION OF A NORTHWESTWARD PROPAGATING CLUSTER OF STORMS ACROSS
   THE DESERTS...INTO THE PHOENIX AREA...WHERE THERMODYNAMIC PROFILES
   SHOULD BE CONDUCIVE TO STRONG SURFACE GUSTS.

   ..KERR.. 07/02/2014

   CLICK TO GET WUUS03 PTSDY3 PRODUCT

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z