Jul 16, 2008 2000 UTC Day 1 Convective Outlook
Updated: Wed Jul 16 20:02:19 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20080716 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080716 2000 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20080716 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080716 2000 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 161958
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0258 PM CDT WED JUL 16 2008
   
   VALID 162000Z - 171200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS NEB/DAKOTAS EWD ACROSS
   MUCH OF LOWER MI...
   
   ...SYNOPSIS...
   NEARLY ZONAL FLOW REGIME WILL CONTINUE ACROSS NRN TIER OF STATES --
   PERTURBED PRIMARILY BY POSITIVELY TILTED SHORTWAVE TROUGH OVER
   PACIFIC NW/BC AND BY SRN FRINGES OF SHORTWAVE TROUGH MOVING EWD
   ACROSS QUE AND ST LAWRENCE VALLEY REGION.  MEANWHILE...DEEP-LAYER
   LOW OVER ERN GULF AND FL WILL CONTINUE TO ENHANCE TSTM
   POTENTIAL...WELL INTO OVERNIGHT HOURS AS WELL AS WITH ONGOING
   DIURNAL CYCLE.
   
   AT SFC...WAVY/QUASISTATIONARY FRONTAL ZONE IS ANALYZED FROM SERN
   ONT/SWRN QUE SWWD ACROSS ONT JUST N OF LE...THEN WNWWD ACROSS LOWER
   MI INTO WI.  BOUNDARY IS MOVING EWD AS COLD FRONT TOWARD ST LAWRENCE
   VALLEY...BUT HAS BECOME QUASISTATIONARY FROM N OF LE BACK INTO WI. 
   FARTHER W...BAROCLINIC ZONE IS DOMINATED BY CONVECTIVE OUTFLOWS OVER
   SRN WI AND SRN MN...THEN IS DIFFUSE ACROSS NERN THROUGH CENTRAL SD
   INTO WEAK SFC LOW OVER SWRN SD.  COLD FRONT THEN IS ANALYZED WSWWD
   ACROSS BLACK HILLS REGION INTO E-CENTRAL WY.  WRN FRONTAL SEGMENT
   SHOULD CONTINUE TO MOVE SLOWLY SWD ACROSS CENTRAL/WRN SD AND
   WY...WHILE REMAINING NEARLY STATIONARY ELSEWHERE AWAY FROM
   CONVECTIVE OUTFLOWS.  SFC TROUGH IS ANALYZED FROM SD LOW NNEWD
   ACROSS CENTRAL ND...AND IS BECOMING NEARLY COLLOCATED WITH LEADING
   EDGE OF SECONDARY COLD FRONTAL SURGE MOVING EWD FROM WRN ND. 
   COMBINED BOUNDARY WILL MOVE EWD ACROSS MOST OF ND DURING REMAINDER
   PERIOD.
   
   ...WI...LM...LOWER MI...
   COMPLEX OF STG-SVR TSTMS IS ONGOING ACROSS PART OF WI...WITH
   PREDOMINANT THREATS BEING SVR GUSTS AND LARGE HAIL.  REF WW 693 AND
   RELATED MESOSCALE DISCUSSION FOR NOWCAST DETAILS.  ASSOCIATED SVR
   WIND POTENTIAL SHOULD DIMINISH SOMEWHAT OVER LM WATERS AS
   SHALLOW/COOL/STABLE MARINE LAYER REDUCES DCAPE AND PERMITS ONLY MOST
   INTENSE/SPORADIC GUSTS TO PENETRATE TO SFC AOA SVR LEVELS. 
   HOWEVER...FOREGOING AIR MASS ACROSS LOWER MI HAS DESTABILIZED
   FAVORABLY AND WILL SUPPORT ENHANCED POTENTIAL FOR SVR...BOTH WITH
   DEVELOPMENT THERE AHEAD OF MCS...AND WITH EVENTUAL MCS INTRUSION
   FROM LM.  REF SPC MESOSCALE DISCUSSION 1791 FOR NEAR-TERM DETAILS
   OVER LOWER MI.
   
   ...N-CENTRAL PLAINS TO UPPER MS VALLEY...
   POTENTIAL REMAINS FOR TSTM DEVELOPMENT LATER THIS AFTERNOON INTO
   EVENING INVOF FRONTAL ZONE ACROSS ERN SD AND SERN ND...POTENTIALLY
   EVOLVING UPSCALE INTO ANOTHER CLUSTER OF TSTMS THAT...IN
   TURN...WOULD MOVE ESEWD OVER PORTIONS MN/WI.  SVR GUSTS AND
   LARGE/DAMAGING HAIL WILL BE POSSIBLE.  SFC ANALYSIS SHOWS RELATIVELY
   DRY AREA ACROSS PORTIONS NWRN IA...SWRN MN AND ERN SD...REPRESENTING
   LOW LEVEL TRAJECTORIES EMANATING FROM OUTFLOW OF PRIOR/OVERNIGHT MCS
   IN IA.  WHILE ASSOCIATED WEAKNESS IN BOUNDARY LAYER THETAE WILL
   LIMIT CAPE SOMEWHAT...PRIND AIR MASS WILL DESTABILIZE SUFFICIENTLY
   TO SUPPORT ADDITIONAL DEVELOPMENT LATER THIS PERIOD.  ADDITIONAL
   MOISTENING IS EXPECTED FROM COMBINATION OF ADVECTIVE AND
   EVAPOTRANSPIRATIVE PROCESSES...THE FORMER CONTINUING AFTER DARK AS
   25-35 KT LLJ CONTRIBUTES TO INCREASINGLY MOIST INFLOW AIR MASS.  SVR
   GUST POTENTIAL MAY DIMINISH AS ANY SUCH COMPLEX MOVES ATOP OUTFLOW
   POOL LEFT BEHIND BY CURRENT WI COMPLEX...HENCE RELATIVE DIMINISHMENT
   OF WIND PROBABILITIES EWD INTO WI.
   
   SEPARATE AREA OF WIDELY SCATTERED-SCATTERED TSTMS IS POSSIBLE ACROSS
   SWRN SD SWD OVER WRN NEB AND ERN CO.  ALTHOUGH LOW-MIDLEVEL FLOW AND
   DEEP-LAYER SHEAR SHOULD BE WEAK...STRONGLY HEATED AND WELL MIXED
   BOUNDARY LAYER WILL SUPPORT STG-SVR GUSTS AND HAIL FROM MOST INTENSE
   CELLS.
   
   ...ERN GREAT LAKES REGION...
   ISOLATED TSTMS ARE DEVELOPING ATTM OVER PORTIONS WRN NY...BECOMING
   WIDELY SCATTERED WWD ACROSS SRN ONT WHERE COMBINED FRONTAL/LAKE
   BREEZE BOUNDARY IS MAXIMIZING LOW LEVEL CONVERGENCE.  AS THIS
   ACTIVITY...AND ANY FRONTAL DEVELOPMENT INVOF FAR ERN ONT -- MOVES
   INTO FAVORABLY DESTABILIZED AND WEAKLY CAPPED AIR MASS...POTENTIAL
   WILL INCREASE FOR ISOLATED SVR HAIL AND DAMAGING GUSTS NEAR SVR
   LEVELS.
   
   ..EDWARDS/KIS.. 07/16/2008
   
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