SPC AC 020725

   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0225 AM CDT SAT MAY 02 2015

   VALID 041200Z - 051200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS MONDAY AFTERNOON AND EVENING
   ACROSS PARTS OF THE SOUTHERN HIGH PLAINS...THE CENTRAL
   PLAINS...UPPER PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY AND
   SOUTHERN PORTIONS OF THE GREAT LAKES REGION...

   ...SUMMARY...
   ISOLATED TO WIDELY SCATTERED STRONG STORMS ARE EXPECTED MONDAY
   WITHIN A CORRIDOR FROM THE SOUTHERN HIGH PLAINS...THROUGH THE
   CENTRAL PLAINS...INTO PARTS OF THE MIDDLE MISSISSIPPI VALLEY AND
   SOUTHERN PORTIONS OF THE GREAT LAKES REGION.  SOME OF THESE COULD
   BECOME CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL AND LOCALIZED
   STRONG WIND GUSTS.

   ...SYNOPSIS...
   WITHIN THE STRONGEST BRANCH OF WESTERLIES EMANATING FROM THE
   MID-LATITUDE PACIFIC...A LEAD SHORT WAVE IMPULSE APPEARS LIKELY TO
   PROGRESS RAPIDLY EASTWARD THROUGH THE REMAINDER OF THE EASTERN
   CANADIAN PROVINCES DURING THIS PERIOD...AS THE CENTER OF A BROADER
   SCALE VORTEX REDEVELOPS EAST OF HUDSON BAY.  UPSTREAM...A COUPLE OF
   SIGNIFICANT PERTURBATIONS ARE FORECAST TO REMAIN PROGRESSIVE ACROSS
   THE NORTHERN PACIFIC...INCLUDING ONE LIKELY TO REACH THE PACIFIC
   NORTHWEST COAST BY MONDAY NIGHT...BUT THE LARGER-SCALE PATTERN MAY
   BEGIN TO UNDERGO AMPLIFICATION.  IN RESPONSE TO THESE LATTER
   DEVELOPMENTS...MODELS INDICATE THAT A MID-LEVEL CLOSED
   LOW/TROUGH...WITHIN A WEAKER SOUTHERN BRANCH OF MID-LATITUDE
   WESTERLIES...WILL CONTINUE INLAND ACROSS THE SOUTHWESTERN U.S. AND
   ADJACENT NORTHERN MEXICO...IN PHASE WITH THE SUBTROPICAL
   STREAM...LIKELY APPROACHING THE SOUTHERN ROCKIES BY 12Z TUESDAY. 
   DOWNSTREAM...FURTHER AMPLIFICATION OF HIGH-LEVEL TROUGHING MAY OCCUR
   ACROSS THE CARIBBEAN AND ADJACENT SOUTHEASTERN GULF OF MEXICO.

   IN LOWER LEVELS...THE COLD FRONT ASSOCIATED WITH THE EASTERN
   CANADIAN IMPULSE IS FORECAST TO ADVANCE EAST OF THE LOWER GREAT
   LAKES...THROUGH MUCH OF THE NORTHEAST...WHILE STALLING...OR PERHAPS
   BEGINNING TO SHIFT NORTHWARD...ACROSS PARTS OF THE SOUTHERN GREAT
   LAKES...MIDDLE MISSISSIPPI VALLEY AND CENTRAL PLAINS.  AS SURFACE
   RIDGING REMAINS PROMINENT ACROSS MUCH OF THE NORTHERN GULF OF MEXICO
   AND GULF COAST REGION...A RETURN FLOW OF RICH MOISTURE FROM THE GULF
   OF MEXICO WILL CONTINUE TO BE INHIBITED.  HOWEVER...SEASONABLY
   MODEST MOISTENING /CHARACTERIZED BY SURFACE DEW POINTS AROUND 60F/
   PROBABLY WILL PROCEED ON SOUTHEASTERLY UPSLOPE FLOW INTO THE
   SOUTHERN HIGH PLAINS...AS WELL AS WITHIN A CORRIDOR ALONG THE
   FRONTAL ZONE.

   ...SRN PLAINS INTO CNTRL PLAINS/MID MS VALLEY/SRN GREAT LAKES...
   A NARROW CORRIDOR OF STRONGER DAYTIME HEATING AND DESTABILIZATION IS
   EXPECTED TO BECOME FOCUSED BY LATE MONDAY AFTERNOON JUST SOUTH OF
   THE SURFACE FRONT...AND TO THE IMMEDIATE LEE OF THE HIGHER TERRAIN
   OF EASTERN NEW MEXICO AND SOUTHWEST TEXAS.  THIS SEEMS LIKELY TO
   OCCUR BENEATH LINGERING STEEP MID-LEVEL LAPSE RATES ASSOCIATED WITH
   RESIDUAL ELEVATED MIXED LAYER AIR...WHICH PROBABLY WILL CONTRIBUTE
   TO CONDITIONS CONDUCIVE TO VIGOROUS CONVECTIVE DEVELOPMENT. 
   ALTHOUGH DEEP LAYER FLOW AND SHEAR MAY REMAIN GENERALLY WEAK ACROSS
   MOST AREAS...ISOLATED TO WIDELY SCATTERED STORMS CAPABLE OF
   PRODUCING AT LEAST MARGINALLY SEVERE HAIL AND LOCALLY STRONG WIND
   GUSTS APPEARS POSSIBLE...MAINLY DURING THE AFTERNOON AND EVENING.

   ..KERR.. 05/02/2015

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