Jul 7, 2015 1630 UTC Day 1 Convective Outlook
Updated: Tue Jul 7 16:27:03 UTC 2015 (20150707 1630Z Day 1 shapefile | 20150707 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150707 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 175,642 25,599,600 Indianapolis, IN...Columbus, OH...Cleveland, OH...Pittsburgh, PA...Cincinnati, OH...
Probabilistic Tornado Graphic
20150707 1630 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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20150707 1630 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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 175,446 25,600,187 Indianapolis, IN...Columbus, OH...Cleveland, OH...Pittsburgh, PA...Cincinnati, OH...
Probabilistic Large Hail Graphic
20150707 1630 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.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 30,737 261,196 Rapid City, SD...Gillette, WY...Dickinson, ND...Spearfish, SD...Rapid Valley, SD...
   SPC AC 071627

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1127 AM CDT TUE JUL 07 2015

   VALID 071630Z - 081200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER THE LOWER GREAT LAKES AND
   OH VALLEY...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER A PART OF THE NRN HIGH
   PLAINS...

   ...SUMMARY...
   SCATTERED MAINLY AFTERNOON STORMS WITH LOCALLY DAMAGING GUSTS MAY
   OCCUR OVER PARTS OF THE OHIO VALLEY AND LOWER GREAT LAKES. ISOLATED
   STORMS WITH MARGINALLY SEVERE HAIL AND WIND MAY OCCUR OVER THE
   NORTHERN HIGH PLAINS LATE THIS AFTERNOON AND EVENING.

   ...SYNOPSIS...

   A SHORT-WAVE TROUGH FROM HUDSON BAY TO THE UPPER GREAT LAKES WILL
   WEAKEN WHILE PROGRESSING EWD INTO ONTARIO AHEAD OF AN AMPLIFYING
   SYSTEM OVER THE CANADIAN PRAIRIE PROVINCES.  ELSEWHERE...AN UPPER
   LOW WILL EDGE EWD TOWARD THE CNTRL CA COAST WHILE A SERIES OF
   LOW-AMPLITUDE PERTURBATIONS TRAVERSE LOCATIONS FROM THE CNTRL/SRN
   ROCKIES EWD TO THE MID-ATLANTIC COAST.

   AT THE SURFACE...A COLD FRONT WILL ADVANCE EWD THROUGH THE LOWER
   GREAT LAKES INTO NEW ENGLAND WITH THE TRAILING SEGMENT OF THE FRONT
   SETTLING SEWD THROUGH THE OH VALLEY.  FARTHER SW...A FRONTAL WAVE
   WILL DEEPEN SLIGHTLY WHILE DEVELOPING FROM W-CNTRL TX INTO CNTRL OK.
   THE SEGMENT OF THE AFOREMENTIONED COLD FRONT IMMEDIATELY DOWNSTREAM
   FROM THIS LOW WILL STALL AND PERHAPS DEVELOP SLIGHTLY NWD ACROSS THE
   OZARK PLATEAU REGION.  OVER THE NRN HIGH PLAINS...A WEAK COLD FRONT
   WILL PROGRESS SEWD THROUGH CNTRL AND ERN PARTS OF MT INTO THE WRN
   DAKOTAS BY EVENING. 

   ...NRN HIGH PLAINS THIS AFTERNOON INTO EVENING...

   DAYTIME HEATING WILL COMBINE WITH BOUNDARY-LAYER DEWPOINTS IN THE
   50S TO OFFSET POOR MID-LEVEL LAPSE RATES /PER 12Z RAOBS/ TO SUPPORT
   A MARGINALLY UNSTABLE AIR MASS AHEAD OF THE COLD FRONT LATER TODAY.
   THIS BOUNDARY AND FAVORED TERRAIN MAY FOCUS ISOLATED STORM
   DEVELOPMENT BY MID TO LATE AFTERNOON AS THE BACKGROUND ENVIRONMENT
   IS FURTHER CONDITIONED BY A WEAK PERTURBATION TRANSLATING SEWD
   THROUGH MT.  GIVEN THE PRESENCE OF STEEP LOW-LEVEL LAPSE RATES AND
   MODEST VERTICAL SHEAR...A FEW BRIEFLY SEVERE STORMS ARE POSSIBLE
   WITH THE PRIMARY HAZARDS BEING LOCALLY STRONG WIND GUSTS AND PERHAPS
   SOME HAIL.

   ...LOWER GREAT LAKES/OH VALLEY THIS AFTERNOON AND EVENING...

   VISIBLE SATELLITE AND MOSAIC RADAR DATA INDICATE CONSIDERABLE
   CLOUDINESS AND RELATED SHOWER ACTIVITY AHEAD OF THE COLD FRONT OVER
   IND INTO OH AND KY WHICH WILL SLOW THE DESTABILIZATION PROCESS
   TODAY.  WHERE STRONGER HEATING CAN OCCUR...THE PRESENCE OF A MOIST
   AIR MASS WILL CONTRIBUTE TO MLCAPE VALUES APPROACHING 1000-1500 J/KG
   THROUGH THE PEAK OF THE DIURNAL HEATING CYCLE.  WEAK CAPPING
   OBSERVED BY 12Z RAOBS SHOULD QUICKLY ERODE...ALLOWING FOR A GRADUAL
   INCREASE IN STORMS THIS AFTERNOON BOTH ALONG THE COLD FRONT AND
   OUTFLOW BOUNDARIES PRESENT WITHIN THE PRE-FRONTAL WARM SECTOR.  

   THE STRONGER DEEP-LAYER WIND FIELD AND RESULTING VERTICAL SHEAR WILL
   HAVE A TENDENCY TO RETREAT NWD INTO CANADA WITH THE DE-AMPLIFICATION
   OF THE SHORT-WAVE TROUGH...LIMITING THE POTENTIAL FOR HIGHER-ORDER
   STORM MODES.  NONETHELESS...THE HIGH-PW ENVIRONMENT WILL BE
   FAVORABLE FOR WATER LOADING OF CONVECTIVE DOWNDRAFTS AND AN
   ASSOCIATED RISK FOR DAMAGING OUTFLOW WINDS AT GROUND LEVEL.

   ...SERN OK/N-CNTRL AND NERN TX INTO AR THIS AFTERNOON AND
   EVENING...

   STRONGER HEATING ALONG THE ERN/SRN PERIPHERY OF WIDESPREAD EARLY-DAY
   CLOUDS WILL PROMOTE POCKETS OF MODERATE INSTABILITY AND AN INCREASE
   IN STORM COVERAGE THIS AFTERNOON ALONG AND AHEAD OF THE COLD FRONT. 
   WHILE VERTICAL SHEAR WILL REMAIN RELATIVELY WEAK...SOME ENHANCEMENT
   IN DEEP-LAYER FLOW FIELDS MAY OCCUR OVER PARTS OF THE RED RIVER
   VALLEY IN ASSOCIATION WITH THE SRN PLAINS VORTICITY MAXIMUM.  AS
   SUCH...PORTIONS OF THE AREA COULD BE UPGRADED TO A MARGINAL RISK AT
   20Z ONCE MESOSCALE DETAILS BECOME MORE CLEAR.

   ..MEAD/MOSIER.. 07/07/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z