DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1249 AM CDT FRI JUL 18 2008
   
   VALID 181200Z - 191200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE
   NORTHERN PLAINS....
   
   ...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS PARTS OF THE
   NORTHEAST STATES....
   
   ...SYNOPSIS...
   A COUPLE OF SIGNIFICANT SHORT WAVE IMPULSES ARE EMBEDDED WITHIN A
   BROADLY CYCLONIC BRANCH OF SPLIT POLAR WESTERLIES NEAR THE
   CANADIAN/U.S. BORDER.  ONE OF THESE WAVES HAS BEEN GRADUALLY
   PROGRESSING TOWARD THE UPPER GREAT LAKES REGION.  BUT...AN EASTWARD
   ACCELERATION INTO THE ST. LAWRENCE VALLEY APPEARS LIKELY DURING THIS
   PERIOD...WITHIN CONFLUENT FLOW TO THE SOUTH OF A BROAD TROUGH OVER
   HUDSON BAY AND NORTHERN QUEBEC.  THIS FEATURE WILL CONTINUE TO BE
   PRECEDED BY A WEAKER IMPULSE...WITHIN A BELT OF WESTERLIES EMANATING
   FROM NORTHEAST PACIFIC...WHICH IS PROGGED TO SHIFT TO THE EAST OF
   LAKE ONTARIO...THROUGH NORTHERN NEW ENGLAND...THIS AFTERNOON AND
   EVENING.
   
   THE PROGRESSION OF A MORE PROMINENT UPSTREAM WAVE AND EMBEDDED
   MID-LEVEL CLOSED LOW LIKELY WILL BE SLOWER...TO THE SOUTH OF
   NORTHERN BRANCH RIDGING.  BUT...THE SYSTEM IS EXPECTED TO GRADUALLY
   MIGRATE TO THE EAST SOUTHEAST OF THE CANADIAN ROCKIES TODAY...AS A
   LARGER SCALE TROUGH/CLOSED LOW SYSTEM BEGINS TO DIG TOWARD THE
   BRITISH COLUMBIA COAST.  THE FORMER SYSTEM WILL ALSO BE PRECEDED TO
   THE SOUTH/EAST BY AN IMPULSE WITHIN THE STREAM EMANATING FROM THE
   NORTHEAST PACIFIC...WHICH APPEARS LIKELY TO OVERSPREAD PARTS OF THE
   NORTHERN ROCKIES/HIGH PLAINS DURING AND SHORTLY AFTER THE PEAK
   AFTERNOON HEATING.
      
   ...NORTHEASTERN STATES...
   MODELS SUGGEST DESTABILIZATION SUPPORTIVE OF SCATTERED STRONG/
   LOCALLY SEVERE STORMS WILL OCCUR ACROSS A LARGE PORTION OF THE
   NORTHEAST TODAY...PARTICULARLY NEW ENGLAND...WHERE DEEP LAYER SHEAR
   BENEATH 30-50+ KT WESTERLY 500 MB FLOW WILL BE MODERATE TO STRONG. 
   A TIGHTER LOW-LEVEL THERMAL GRADIENT EXTENDING ACROSS NORTHERN NEW
   YORK STATE/VERMONT AND NEW HAMPSHIRE INTO SOUTHERN MAINE APPEARS
   LIKELY TO BE THE FOCUS FOR HIGHEST SEVERE PROBABILITIES.  THIS IS
   WHERE AN ORGANIZED STORM CLUSTER MAY EVOLVE IN RESPONSE TO FORCING
   ASSOCIATED WITH THE UPPER IMPULSE PROGRESSING ACROSS REGION. 
   COUPLED WITH A STRENGTHENING BELT OF WESTERLY 850 MB FLOW...UP TO
   40-50 KT...THIS WILL SUPPORT POTENTIAL FOR A SWATH OR SWATHS OF
   DAMAGING WIND GUSTS...IN ADDITION TO THE RISK FOR HAIL AND LOCALIZED
   DOWNBURSTS.