Mar 25, 2015 0600 UTC Day 1 Convective Outlook

DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1244 AM CDT WED MAR 25 2015

   VALID 251200Z - 261200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS LATE THIS AFTERNOON AND EVENING
   ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST OKLAHOMA...ADJACENT
   SOUTHEAST KANSAS...SOUTHWEST MISSOURI AND NORTHWEST ARKANSAS...

   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ENH
   RISK...ACROSS PARTS OF THE SOUTH CENTRAL PLAINS INTO THE OZARK
   PLATEAU...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
   CENTRAL AND SOUTHERN PLAINS EAST NORTHEASTWARD INTO PARTS OF THE
   LOWER OHIO VALLEY...

   ...SUMMARY...
   SEVERE THUNDERSTORMS...MAINLY CAPABLE OF PRODUCING LARGE HAIL AND
   LOCALLY DAMAGING WIND GUSTS...ARE EXPECTED ACROSS PARTS OF THE SOUTH
   CENTRAL PLAINS INTO THE OZARK PLATEAU LATE THIS AFTERNOON AND
   EVENING.

   ...SYNOPSIS...
   SIGNIFICANT AMPLIFICATION IS ONGOING WITHIN A BRANCH OF MID-LATITUDE
   WESTERLIES ACROSS THE EASTERN PACIFIC INTO WESTERN NORTH AMERICA. 
   AS LARGE-SCALE MID/UPPER RIDGING CONTINUES TO BUILD NEAR THE PACIFIC
   COAST DURING THIS PERIOD...MODELS INDICATE THAT LARGE-SCALE
   TROUGHING WILL BEGIN TO EVOLVE DOWNSTREAM...EAST OF THE
   ROCKIES...THROUGH THE VICINITY OF THE APPALACHIANS.  

   WITHIN THIS LATTER REGIME...ONE NOTABLE SHORT WAVE IMPULSE IS
   FORECAST TO PIVOT RAPIDLY NORTHEASTWARD...FROM THE OHIO VALLEY
   THROUGH THE ST. LAWRENCE VALLEY BY LATE TONIGHT.  AN ASSOCIATED
   SURFACE LOW MAY CONSOLIDATE WITH ANOTHER LOW OVER THE GREAT LAKES
   REGION...BEFORE CONTINUING INTO QUEBEC LATE IN THE PERIOD...WITH A
   TRAILING COLD FRONT ADVANCING SOUTHEASTWARD ACROSS THE CENTRAL
   UNITED STATES.

   INITIALLY STALLED OVER PARTS OF THE LOWER OHIO VALLEY/OZARK PLATEAU
   AND CENTRAL PLAINS...MODELS SUGGEST THAT THE SOUTHWESTERN FLANK OF
   THIS FRONT WILL BEGIN A MORE RAPID SOUTHWARD SURGE...IN RESPONSE TO
   ANOTHER SIGNIFICANT SHORT WAVE IMPULSE DIGGING SOUTHEAST OF THE
   CENTRAL ROCKIES THROUGH MUCH OF THE SOUTH CENTRAL PLAINS BY 12Z
   THURSDAY.  THIS MAY BE ACCOMPANIED BY WIDESPREAD CONVECTIVE
   DEVELOPMENT...AND THE RISK FOR SEVERE STORMS.

   ...SOUTH CENTRAL PLAINS/OZARK PLATEAU INTO LOWER OHIO VALLEY...
   SOME BOUNDARY LAYER MOISTENING CONTINUES ALONG AND SOUTH OF THE
   FRONT...BUT A SUBSTANTIVE RETURN FLOW OF MOISTURE OFF THE GULF OF
   MEXICO STILL APPEARS UNLIKELY DURING THIS PERIOD.  MODEL SURFACE DEW
   POINT FORECASTS FOR THIS AFTERNOON MAY STILL BE AT LEAST A BIT TOO
   HIGH.  HOWEVER...NORTHEASTWARD ADVECTION OF WARM ELEVATED MIXED
   LAYER AIR IS EXPECTED TO AGAIN CONTRIBUTE TO VERY STEEP MID-LEVEL
   LAPSE RATES BY THIS AFTERNOON.  THIS PROBABLY WILL SUPPORT SIZABLE
   CAPE /PERHAPS AT OR ABOVE 2000 J PER KG/ WITHIN AT LEAST A NARROW
   CORRIDOR ALONG THE FRONTAL ZONE.  IN THE PRESENCE OF STRONG SHEAR
   BENEATH 40-50 KT WESTERLY 500 MB FLOW...CONDITIONS SHOULD BECOME
   CONDUCIVE TO THE DEVELOPMENT OF SEVERE STORMS FOR AT LEAST A PERIOD
   LATE THIS AFTERNOON INTO EARLY EVENING.

   MODELS SUGGEST THAT FORCING FOR ASCENT ASSOCIATED WITH LOW-LEVEL 
   WARM ADVECTION MAY SUPPORT A RAPID INCREASE IN SEVERE STORM
   DEVELOPMENT BY 20-22Z NEAR THE CENTRAL AND EASTERN KANSAS/OKLAHOMA
   BORDER AREA.  THIS MAY INITIALLY INCLUDE DISCRETE STORMS...BEFORE
   GROWING UPSCALE...WHICH SHOULD TEND TO TRACK EASTWARD ALONG THE
   FRONT INTO THE OZARK PLATEAU.  ADDITIONAL SEVERE STORMS MAY FORM
   SHORTLY THEREAFTER ACROSS PARTS OF WEST CENTRAL OKLAHOMA.  IT
   APPEARS THAT THIS LATTER ACTIVITY WILL OCCUR JUST AHEAD OF THE
   SOUTHWARD SURGING COLD FRONT...AND STRONGER STORMS PROBABLY WILL BE
   CAPABLE OF PRODUCING LARGE HAIL AND LOCALLY STRONG WIND GUSTS.

   AS LARGE-SCALE FORCING SUPPORTS INCREASINGLY WIDESPREAD THUNDERSTORM
   ACTIVITY THROUGH MUCH OF THE INSTABILITY AXIS...WHILE THE SURFACE
   COLD FRONT BEGINS TO SURGE SOUTHWARD AND TENDS TO UNDERCUT
   CONVECTION...IT REMAINS UNCLEAR AT THE PRESENT TIME HOW LONG THE
   SEVERE WEATHER POTENTIAL WILL CONTINUE INTO THE EVENING HOURS.