SPC AC 031958
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 PM CDT THU JUL 03 2008
   
   VALID 032000Z - 041200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FOR PORTIONS OF ERN PA NEWD
   INTO SRN NEW ENGLAND...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THE INTERIOR PORTIONS OF THE
   PACIFIC NW...
   
   ...ERN PA NEWD INTO INTO SRN NEW ENGLAND...
   A THICK BAND OF CLOUDS AND EMBEDDED SHOWERS WAS LOCATED AHEAD OF A
   SEWD MOVING COLD FRONT...THAT AT MID AFTERNOON STRETCHED FROM WRN
   NEW ENGLAND SWWD THROUGH NRN NY AND INTO FAR NWRN PA. INSTABILITY IS
   WEAK DUE TO POOR LOW-MID LEVEL LAPSE RATES WITHIN THE THICKER CLOUD
   BAND..AND STRONGER HEATING EAST OF THE CLOUDS HAD MIXED LOWER
   DEWPOINTS TO THE SURFACE. DESPITE WEAK INSTABILITY ...35-40 KT DEEP
   LAYER SHEAR MAY RESULT IN A FEW ORGANIZED STRONGER UPDRAFTS THROUGH
   00Z...ESPECIALLY NEAR THE ERN EDGE OF THICKER CLOUDS.
   
   ...INTERIOR ORE/WA...
   WV IMAGERY SHOWED A MID LEVEL SHORTWAVE TROUGH MOVING ENEWD THROUGH
   WRN WA/ORE. SCATTERED THUNDERSTORMS HAVE BEEN ONGOING MOST OF THE
   MORNING/EARLY AFTERNOON OVER THE CASCADES. AS THIS TROUGH MOVES EWD
   INTO AN INCREASINGLY WARMING AND DESTABILIZING AIR MASS...STORM
   COVERAGE SHOULD INCREASE IN NUMBER AND INTENSITIES SWD INTO
   ORE...AND EWD INTO CENTRAL/ERN WA. ONCE STORMS DEVELOP EAST OF THE
   CASCADES...EFFECTIVE SHEAR IN EXCESS OF 40 KT SHOULD FAVOR A FEW
   SUPERCELLS OR SMALL BOWS. LARGE HAIL AND DAMAGING WINDS WILL BE THE
   PRIMARY SEVERE THREATS BETWEEN 21-03Z.
   
   ...CENTRAL HIGH PLAINS...
   LOW CLOUDS FROM COOL AND MOIST ELY UPSLOPE FLOW WERE GRADUALLY
   DISSIPATING DUE TO SOME HEATING/MIXING. THE AREA WHERE CLOUDS
   PERSISTED INTO THE EARLY AFTERNOON HOURS WILL LIKELY REMAIN CAPPED
   DUE TO A COOLER AND MORE STABLE BOUNDARY LAYER. HOWEVER...STRONG
   INSOLATION OVER THE CLOUD FREE HIGHER TERRAIN HAD RESULTED IN
   THUNDERSTORM DEVELOPMENT. MODERATE INSTABILITY AND DIRECTIONAL SHEAR
   COULD SUPPORT MULTICELL CLUSTERS OR MARGINAL SUPERCELL
   STRUCTURES...WITH THE POSSIBILITY OF ISOLATED HAIL/DAMAGING WINDS
   THROUGH ABOUT 02Z/03Z.
   
   ...OK NEWD INTO THE LOWER OH VALLEY...
   AT MID AFTERNOON...A WEAK COLD FRONT EXTENDED FROM CENTRAL OH SWWD
   THROUGH SWRN OK INTO ERN NM. STRONG SURFACE HEATING ALONG AND S OF
   THE FRONT...TEMPERATURES IN THE 90S...WILL CONTRIBUTE TO MODERATE
   INSTABILITY. HOWEVER...WINDS ALOFT ARE WEAK...SO A FEW CLUSTERS OF
   PULSE-TYPE SEVERE STORMS ARE POSSIBLE THIS AFTERNOON...WITH BRIEF
   MICROBURSTS THE MAIN THREAT.
   
   ...SRN AZ/NM...
   CONVECTION HAD ALREADY DEVELOPED OVER THE RIM EWD INTO THE SRN
   MOUNTAINS OF NM. MID LEVEL NELY WINDS AT 15 TO 20 KT SHOULD
   GRADUALLY PUSH THESE STORMS SSWWD INTO THE DESERT FLOORS...
   ESPECIALLY AS COLD POOLS DEVELOP. STRONG WIND GUSTS ARE CERTAINLY
   POSSIBLE AS CONVECTION MOVES INTO THE VERY HOT ENVIRONMENT WITH
   STEEP LOW LEVEL LAPSE RATES. HOWEVER...RELATIVELY MOIST LAYER
   BETWEEN 500-700 MB ON AREA 12Z SOUNDINGS SUGGEST SEVERE THREAT
   SHOULD BE TOO ISOLATED FOR A SLIGHT RISK.
   
   ..IMY.. 07/03/2008
   
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