Jul 19, 2012 2000 UTC Day 1 Convective Outlook
Updated: Thu Jul 19 20:04:30 UTC 2012
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20120719 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20120719 2000 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20120719 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20120719 2000 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
   SPC AC 192000
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0300 PM CDT THU JUL 19 2012
   
   VALID 192000Z - 201200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE OH
   VALLEY/MID-SOUTH/CENTRAL APPALACHIANS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PORTION OF THE NRN
   PLAINS...
   
   ...OH VALLEY/MID-SOUTH/CENTRAL APPALACHIANS...
   DAMAGING WIND/SOME SEVERE HAIL POTENTIAL WILL CONTINUE INTO EARLY
   EVENING WITH AN MCS ACROSS EASTERN KY/NEARING THE CENTRAL
   APPALACHIANS...AND SPATIAL ADJUSTMENTS HAVE BEEN MADE TO THE SLIGHT
   RISK ACROSS PORTIONS OF THE REGION. OTHER SEVERE TSTMS WILL CONTINUE
   TO DEVELOP FARTHER WEST ESPECIALLY ACROSS PORTIONS OF INDIANA AND
   ADJACENT PARTS OF KY/OH. DAMAGING WINDS/SEVERE HAIL REMAIN PRIMARY
   HAZARDS...BUT A BRIEF TORNADO THREAT MAY EXIST ACROSS AREAS SUCH AS
   CENTRAL INDIANA IN VICINITY OF OUTFLOW BOUNDARY. REFERENCE MESOSCALE
   DISCUSSION 1502 AND WATCHES 495/496 FOR ADDITIONAL SHORT-TERM
   INFORMATION. OTHERWISE...THE SLIGHT RISK WAS ALSO EXPANDED
   SOUTHWESTWARD ACROSS PORTIONS OF THE MID-SOUTH.
   
   ...ELSEWHERE...
   NO CHANGES...SEE PRIOR DISCUSSION BELOW AND MESOSCALE 1501 REGARDING
   PORTIONS OF THE DAKOTAS/MN.
   
   ..GUYER.. 07/19/2012
   
   .PREV DISCUSSION... /ISSUED 1126 AM CDT THU JUL 19 2012/
   
   ...MID/LWR OH VLY...
   LATEST MESOANALYSIS PLACES A 1012 MB LOW OVER NRN IL WITH A FRONT
   DRAPED EWD INTO THE NRN MID-ATLANTIC REGION AND WWD INTO KS.  THE
   LOW WILL MOVE TO VCNTY KCVG BY FRIDAY MORNING WHILE THE TRAILING
   FRONT MOVES INTO THE MID-SOUTH/SRN PLAINS.  
   
   AIR MASS ALONG/S OF THE FRONT WILL REMAIN VERY MOIST WITH
   PRECIPITABLE WATER VALUES IN EXCESS OF 1.75 INCHES.  MULTI-LAYERED
   CLOUDS WILL MITIGATE STRONG DESTABILIZATION ACROSS THE UPR OH VLY. 
   BUT...AREAS TO THE SW FROM SWRN OH/IND AND INTO THE MID-SOUTH WILL
   EXPERIENCE STRONG INSOLATION WITH MLCAPES TO 2500 J/KG.
   
   TSTMS ARE EXPECTED TO GRADUALLY INCREASE ALONG BOTH THE FRONT AND
   RESIDUAL BOUNDARIES TIED TO OUTFLOW AND DIFFERENTIAL HEATING FROM
   THE MID-OH VLY SWWD INTO SERN MO THIS AFTN.  
   
   CURRENT BLEND OF VWP AND FCST HODOGRAPHS INDICATE THAT WNW BULK
   SHEAR WILL REMAIN MODEST AT BEST...AROUND 30 KTS.  HOWEVER... GIVEN
   OVERALL INSTABILITY...MULTICELL STORM CLUSTERS WILL BRIEFLY ORGANIZE
   INTO FORWARD-PROPAGATING SYSTEMS AND PERHAPS BRIEF SUPERCELLS GIVING
   DMGG WIND GUSTS AND HAIL. 
   
   STORMS MAY PERSIST INTO TONIGHT BUT WITH DECREASING SVR THREATS. 
   SMALL MCS OR TWO WILL BE MOST LIKELY VCNTY KY/WV/ERN TN. 
   
   FARTHER  E...SVR THREAT MAY BE A BIT LESS ORGANIZED/MORE SPORADIC
   EWD ACROSS MOUNTAINS TO THE MID ATLANTIC CST. SCTD STG TO
   OCCASIONALLY SVR STORMS SHOULD...NEVERTHELESS...FORM ALONG
   AFOREMENTIONED BOUNDARIES.  CONCENTRATED MULTICELLS COULD YIELD
   LOCALLY DMGG WIND AND MARGINALLY SVR HAIL INTO THIS EVE.
   
   ...NRN PLAINS...
   ELEVATED TSTMS WERE ONGOING LATE THIS MORNING OVER ND/SD AMIDST WEAK
   LOW/MID-LVL WARM ADVECTION.  THESE STORMS MAY PRODUCE SOME
   HAIL...BUT MAIN CONDITIONAL SVR THREAT WILL EVOLVE THIS AFTN/EVE. 
   
   ON THE LARGER SCALE...BUILDING HEIGHTS/STRENGTHENING EML WOULD ARGUE
   AGAINST SFC-BASED TSTM DEVELOPMENT AS PARCELS FAIL TO REACH THEIR
   LFC/S.  HOWEVER...RICH BOUNDARY LAYER MOISTURE AND MAINTENANCE OF
   CONVERGENCE ALONG THE LEE TROUGH WILL LIKELY BE SUFFICIENT FOR A
   COUPLE STORMS OVER CNTRL/ERN ND BY LATE THIS AFTN.  THIRTY-35 KT
   0-8KM SHEAR AND MAGNITUDE OF MID-LVL LAPSE RATES...ON THE ORDER OF 8
   DEG C PER KM...WILL BE SUFFICIENT FOR SUPERCELLS AND MULTICELL
   CLUSTERS GIVING VERY LARGE HAIL AND DMGG WIND GUSTS. A TORNADO OR
   TWO CANNOT BE RULED OUT IN THE RED RIVER VLY AND ADJACENT ERN ND.  
   
   OVERNIGHT...A SSE PROPAGATING CLUSTER OF STORMS...WILL CLIP PARTS OF
   NWRN MN AND NERN SD WITH AT LEAST LOW-END RISKS FOR LARGE HAIL AND
   PERHAPS HIGH WINDS.
     
   ...INTERIOR PAC NW...
   MUCH LIKE YESTERDAY...WDLY SCTD TO LOCALLY SCTD AFTN/EVE TSTMS
   EXPECTED WITH SFC HEATING IN ZONE OF MODERATE MOISTURE OVER HIGHER
   TERRAIN IN NE QUADRANT OFF OFFSHORE LOW...FROM THE ORE CASCADES ENE
   INTO ERN WA/WRN ID.  ISOLD SVR HAIL/GUSTS MAY OCCUR. SOME OF THE
   STORMS MAY PERSIST/REDEVELOP THROUGH EARLY FRI AS UPR LVL DIFLUENCE
   INCREASES WITH THE NEWD ACCELERATION OF THE OFFSHORE LOW.  GIVEN
   40-50 KT CLOUD LAYER SHEAR AND CONTINUED NE ADVANCE OF UPR
   TROUGH...A FEW OF THE STORMS COULD REMAIN LOCALLY STRONG TO SVR.
   
   ...SERN U.S. THIS AFTN...
   SCTD TO LOCALLY NUMEROUS TSTMS IN CLUSTERS AND LOOSELY
   ORGANIZED BANDS LIKELY WILL FORM AGAIN TODAY OVER MUCH OF THE SERN
   STATES. AREA SOUNDINGS DO...HOWEVER...APPEAR SOMEWHAT STABILIZED
   RELATIVE TO YESTERDAY...LIKELY REFLECTING SIZABLE OVERTURNING THAT
   OCCURRED THERE. AFOREMENTIONED WEAK UPR CIRCULATIONS WILL ONCE AGAIN
   LARGELY GOVERN WHERE CONVECTION BECOMES MOST CONCENTRATED.  A FEW
   STORMS MAY YIELD LOCALLY DMGG WIND.
   
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