SPC AC 071717
   
   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1217 PM CDT SUN MAY 07 2006
   
   VALID 081200Z - 091200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN AND
   CNTRL PLAINS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE ARKLATEX...
   
   ...SYNOPSIS...
   
   MID-LEVEL TROUGH INITIALLY OVER THE CANADIAN AND NRN ROCKIES WILL
   INTENSIFY THROUGH THE FORECAST PERIOD AS IT TRANSLATES SEWD INTO THE
   NRN PLAINS ALONG CYCLONIC SIDE OF UPPER JET STREAK DIVING SEWD
   TOWARD THE CNTRL ROCKIES.  MEANWHILE...SRN STREAM IMPULSE /INITIALLY
   OVER CNTRL KS INTO N-CNTRL TX/ WILL PROGRESS ESEWD TOWARD THE LOWER
   MS VALLEY.
   
   IN THE LOW-LEVELS...SURFACE LOW ASSOCIATED WITH NRN PLAINS SHORT
   WAVE TROUGH WILL DEVELOP SEWD FROM CNTRL SASKATCHEWAN INTO SRN
   MANITOBA WITH TRAILING COLD FRONT LIKELY EXTENDING FROM THE RED
   RIVER VALLEY OF THE N SWWD INTO SWRN NEB BY LATE AFTERNOON.  A LEE
   TROUGH OR DRY LINE WILL STRETCH SEWD FROM ITS INTERSECTION WITH COLD
   FRONT OVER SWRN NEB SWD THROUGH WRN OR CNTRL KS INTO WRN OK AND
   W-CNTRL TX.  FARTHER SE...QUASI-STATIONARY BOUNDARY WILL EXTEND FROM
   NRN FL WWD ALONG THE GULF COAST...WITH WRN EXTENSION OF BOUNDARY
   RETREATING NWD THROUGH RED RIVER VALLEY OF THE S.
   
   ...NRN AND CNTRL PLAINS...
   
   DESPITE INCREASING SLY FLOW AHEAD OF COLD FRONT...LOW-LEVEL MOISTURE
   WILL REMAIN SOMEWHAT LIMITED WITH DEWPOINTS OF 45-55 F. 
   HOWEVER...THE PRESENCE OF MODERATELY STEEP LOW AND MID-LEVEL LAPSE
   RATES WILL COMPENSATE TO SOME DEGREE FOR THE MARGINAL
   MOISTURE...WITH MLCAPES INCREASING TO 500-1500 J/KG.  TSTMS WILL
   BECOME INCREASINGLY LIKELY BY AFTERNOON INITIALLY ALONG NRN
   EXTENSION OF COLD FRONT OVER THE ERN DAKOTAS/WRN MN WITH SUBSEQUENT
   DEVELOPMENT SWWD INTO CNTRL/ERN NEB BY LATE AFTERNOON OR EARLY
   EVENING.  DEEP-LAYER SHEAR IS FORECAST TO BE MARGINALLY SUPPORTIVE
   /25-35 KTS/ OF ORGANIZED SEVERE STORMS WITH THE PRIMARY THREATS
   BEING SEVERE HAIL AND LOCALLY DAMAGING WINDS.
   
   ADDITIONAL STORMS MAY ALSO DEVELOP SWD ALONG SRN PORTION OF COLD
   FRONT AND/OR LEE TROUGH/DRY LINE INTO KS LATE MONDAY AFTERNOON INTO
   EVENING.  HERE TOO...DEEP-LAYER SHEAR WILL BE MARGINAL THOUGH LARGE
   HAIL/STRONG WINDS WILL REMAIN POSSIBLE WITH THE STRONGEST CELLS.
   
   ...SRN PLAINS INTO LOWER MS VALLEY...
   
   MORE UNCERTAINTY EXISTS ACROSS THIS REGION OWING TO POTENTIAL
   EFFECTS OF ONGOING STORMS MONDAY MORNING OVER OK INTO N TX AND
   TIMING OF WEAKER SRN STREAM IMPULSE. CLOSE PROXIMITY OF RICH
   BOUNDARY-LAYER MOISTURE /UPPER 60 TO LOWER 70S DEWPOINTS CURRENTLY
   OVER SERN TX/SRN LA/ SHOULD SUPPORT AIR MASS DESTABILIZATION
   /MLCAPES OF 1000-2000 J/KG/ ALONG AND S OF FRONTAL BOUNDARY WHICH
   WILL RETREAT NWD THROUGH THE SRN LOW PLAINS.
   
   AS MENTIONED ABOVE...STORM CLUSTERS OR AN MCS WILL LIKELY BE ONGOING
   OVER PORTIONS OF OK AND PERHAPS N TX MONDAY MORNING IN ADVANCE OF
   SRN STREAM IMPULSE.  SOME DIURNAL WEAKENING MAY OCCUR THROUGH THE
   MORNING...WITH STORM RE-INTENSIFICATION OR NEW DEVELOPMENT ALONG SRN
   EDGE OF COLD POOL BY AFTERNOON OVER THE ARKLATEX.  THE STRONGER
   FORCING FOR ASCENT ASSOCIATED WITH AFOREMENTIONED SHORT WAVE TROUGH
   WILL LIKELY HAVE SHIFTED E OF THE REGION BY THIS TIME...BUT
   MESOSCALE FORCING ALONG OUTFLOW BOUNDARY AND SYNOPTIC FRONT MAY BE
   SUFFICIENT TO MAINTAIN ANY DEVELOPING DEEP CONVECTION.
   
   SHOULD STORMS BECOME SUSTAINED...FORECAST VERTICAL SHEAR PROFILES
   WILL BE QUITE SUPPORTIVE OF SUPERCELLS WITH 45-55 KTS OF DEEP-LAYER
   SHEAR AND 0-1 KM SRH OF 100-200 M2/S2. POTENTIAL WILL EXIST FOR
   LARGE HAIL...DAMAGING WINDS AND A FEW TORNADOES WITH THE MOST
   INTENSE STORMS.  UNCERTAINTY IN DEVELOPMENT AND MAINTENENCE OF
   STORMS PRECLUDES HIGHER SEVERE PROBABILITIES.
   
   ..MEAD.. 05/07/2006
   
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