SPC AC 210959
   
   DAY 3 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0459 AM CDT MON JUN 21 2004
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL/NRN
   PLNS AND LWR MO VLY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE
   CAROLINAS/VA...
   
   ...SYNOPSIS...
   YET ANOTHER STRONG IMPULSE WILL DROP S/SE ALONG WRN FRINGE OF DEEP
   CYCLONE OVER ONTARIO ON WEDNESDAY AS HIGH LATITUDE BLOCKS LINGER
   OVER BAFFIN ISLAND AND WRN CANADA.  THIS WILL MAINTAIN BROAD 
   CYCLONIC REGIME ACROSS THE NRN AND ERN U.S.  MEANWHILE...LEAD
   IMPULSE WHICH WILL REACH THE UPR GRT LKS EARLY WEDNESDAY EXPECTED TO
   SWEEP E ACROSS THE LWR LKS AND WRN NEW ENGLAND BY THE END OF THE
   PERIOD.
   
   THE MEAN WNWLY FLOW OVER THE CNTRL U.S. WILL TEND TO MINIMIZE LOW
   LEVEL MOISTURE AVAILABILITY OVER THE NRN HALF OF THE PLNS AND MS
   VLY.  BUT COMBINATION OF STEEP MID LEVEL LAPSE RATES...FAST CYCLONIC
   FLOW...AND PERIODIC LARGE SCALE ASCENT ASSOCIATED WITH PASSING
   SHORTWAVE DISTURBANCES SIGNAL THE START OF AN ACTIVE CONVECTIVE
   PATTERN OVER PARTS OF THE CNTRL AND ERN U.S. LATER WEDNESDAY THAT
   MAY CONTINUE THROUGH THE REMAINDER OF THE WEEK.
   
   ...CNTRL/NRN HI PLNS E/SE INTO THE LWR MO AND MID MS VLYS...
   LOW LEVEL WARM ADVECTION WILL INCREASE OVER PARTS OF THE CNTRL/NRN
   PLNS AND LWR MO VLY LATER WEDNESDAY...AHEAD OF STRONG UPPER IMPULSE
   DROPPING S TOWARD ND/MN.  BOUNDARY LAYER ENVIRONMENT WILL INITIALLY
   BE RATHER DRY...ESPECIALLY OVER THE NRN PLNS.  BUT INCREASING LOW
   LEVEL SWLY FLOW WILL ALLOW SIGNIFICANT MOISTURE TO OVERSPREAD PARTS
   OF THE CNTRL PLNS AND LWR MO VLY BY LATE IN THE DAY/EARLY AT NIGHT.
   
   COMBINATION OF INCREASING MOISTURE WITH STEEP MID LEVEL LAPSE RATES
   AND STRONGLY VEERING WIND PROFILES SHOULD PROVE FAVORABLE FOR
   DEVELOPMENT OF A FEW SUPERCELLS WITH LARGE HAIL/HIGH WIND AND
   POSSIBLY A TORNADO OVER PARTS OF ERN CO/NEB/NRN KS.  THESE STORMS
   MAY CONSOLIDATE INTO AN MCS THAT REACHES IA/SRN MN WITH A HAIL/WIND
   THREAT EARLY THURSDAY.
   
   OTHER STORMS MAY DEVELOP EARLIER IN THE DAY IN ZONES OF LOW LEVEL
   CONFLUENCE EXTENDING NWWD INTO THE MT/WY RCKYS. MUCH OF THIS
   ACTIVITY WILL LIKELY BE HIGH-BASED...BUT MAY POSE A THREAT FOR HIGH
   WIND GIVEN STRENGTH OF MEAN WNWLY FLOW /30-40 KT/ AND EXPECTED
   STRONG SURFACE HEATING.
   
   ...CAROLINAS/VA...
   SCATTERED AREAS/LINES OF DIURNALLY ENHANCED STORMS ARE EXPECTED OVER
   PARTS OF THE CAROLINAS AND VA ON WEDNESDAY...AS FRONT WHICH WILL
   CROSS THE MID ATLANTIC REGION ON TUESDAY SETTLES SWD. 30 KT
   UNIDIRECTIONAL WSWLY MEAN FLOW WILL TEND TO MINIMIZE CONVERGENCE
   ...BUT MAY FOSTER DEVELOPMENT OF N/S ORIENTED BOWING SEGMENTS WITH
   LOCALLY DAMAGING WIND.
   
   ..CORFIDI.. 06/21/2004
   
   ...NOTICE...
   FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
   LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
   GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
   HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3.  THE
   INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
   
   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED FOR 1200Z