Jul 30, 2016 1630 UTC Day 1 Convective Outlook
Updated: Sat Jul 30 16:25:05 UTC 2016 (20160730 1630Z Day 1 shapefile | 20160730 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160730 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 24,373 221,005 Rapid City, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...Belle Fourche, SD...
MARGINAL 194,107 34,370,548 Philadelphia, PA...Detroit, MI...Baltimore, MD...Washington, DC...Cleveland, OH...
Probabilistic Tornado Graphic
20160730 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
20160730 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 % 168,543 34,072,164 Philadelphia, PA...Detroit, MI...Baltimore, MD...Washington, DC...Cleveland, OH...
Probabilistic Large Hail Graphic
20160730 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
SIG SEVERE 12,326 164,036 Rapid City, SD...Rapid Valley, SD...
15 % 24,256 220,916 Rapid City, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...Belle Fourche, SD...
5 % 118,982 929,630 Salina, KS...Manhattan, KS...Grand Island, NE...Kearney, NE...North Platte, NE...
   SPC AC 301625

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1125 AM CDT SAT JUL 30 2016

   VALID 301630Z - 311200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTERNOON AND/OR
   TONIGHT ACROSS THE BLACK HILLS REGION...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS SURROUNDING AREAS OF THE
   HIGH PLAINS INTO LOWER CENTRAL PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS THIS AFTERNOON NEAR LAKE
   ERIE...

   ...THERE IS A MRGL RISK OF SVR TSTMS TO THE EAST OF THE ALLEGHENY
   MOUNTAINS AND BLUE RIDGE...INTO NORTHERN MID ATLANTIC COASTAL
   AREAS...

   ...SUMMARY...
   ISOLATED STRONG TO LOCALLY SEVERE THUNDERSTORMS ARE POSSIBLE FROM
   NEAR THE BLACK HILLS INTO THE CENTRAL HIGH PLAINS...ACROSS THE MID
   ATLANTIC COAST REGION...AND PERHAPS ACROSS PARTS OF THE LOWER GREAT
   LAKES REGION THIS AFTERNOON AND EVENING.  A FEW STRONG STORMS ARE
   ALSO POSSIBLE LATE TONIGHT OVER THE CENTRAL PLAINS.

   ...SYNOPSIS...
   WITHIN ONE BELT OF MID-LATITUDE WESTERLIES...A BROAD CLOSED LOW AND
   UPPER TROUGH APPEAR LIKELY TO CONTINUE SHIFTING EAST OF THE CANADIAN
   ROCKIES...AND ADJACENT INTERNATIONAL BORDER AREA...TOWARD THE
   CANADIAN PRAIRIES.  AS THIS OCCURS...MODELS INDICATE SOME
   AMPLIFICATION OF SHORT WAVE RIDGING DOWNSTREAM...ACROSS THE NORTHERN
   HIGH PLAINS...WITHIN A WEAKER BELT OF WESTERLIES ON THE NORTHERN
   PERIPHERY OF GENERALLY FLAT SUBTROPICAL RIDGING ACROSS THE SOUTHERN
   TIER STATES.  AT THE SAME TIME...A RESIDUAL SUBTROPICAL HIGH
   CENTER...WHICH HAS BEEN OVER THE SOUTHERN GREAT BASIN THE PAST FEW
   DAYS...MAY CONTINUE TO REDEVELOP EASTWARD ACROSS PARTS OF THE
   SOUTHERN ROCKIES.

   DOWNSTREAM OF THE NORTHERN HIGH PLAINS MID/UPPER RIDGING...BROAD
   TROUGHING LINGERS...WITH A CONTINUED SLOW EASTWARD PROGRESSION
   ACROSS THE OHIO VALLEY.  IN LOWER LEVELS...A DIFFUSE FRONTAL ZONE
   ARCS WESTWARD ACROSS THE LOWER OHIO/MIDDLE MISSISSIPPI VALLEYS INTO
   THE CENTRAL PLAINS...FROM AN AREA OF LOWER PRESSURE IN THE LAKE ERIE
   VICINITY.  EAST OF THE LOW...THE FRONTAL ZONE IS A BIT MORE DISTINCT
   ACROSS THE UPPER OHIO VALLEY INTO MID ATLANTIC COAST REGION.

   SEASONABLY HIGH MOISTURE CONTENT AIR IS GENERALLY CONFINED TO AREAS
   SOUTH/SOUTHEAST OF THE FRONTAL ZONE TO THE EAST OF THE ROCKIES...AND
   ACROSS PARTS OF THE LOWER COLORADO VALLEY.  STEEP MID-LEVEL LAPSE
   RATES ARE MOSTLY CONFINED TO THE INTERMOUNTAIN WEST/ROCKIES AND
   ADJACENT HIGH PLAINS.  BUT...INCREASINGLY WARM ELEVATED MIXED LAYER
   AIR...EMERGING FROM THE INTERMOUNTAIN REGION...APPEARS LIKELY TO
   EDGE EASTWARD ACROSS THE NORTHERN AND CENTRAL PLAINS THROUGH LATE
   TONIGHT...IN RESPONSE TO THE PROGRESSION OF THE WESTERN CANADIAN
   IMPULSE.

   ...NORTH CENTRAL PLAINS...
   POTENTIAL FOR INCREASING INHIBITION WITH GRADUAL MID-LEVEL WARMING
   AND HEIGHT RISES...COUPLED WITH PERHAPS SOMEWHAT MODEST LOW-LEVEL
   MOISTURE...CONTRIBUTE TO UNCERTAINTY WITH REGARD TO CONVECTIVE
   POTENTIAL TODAY.

   AN AREA OF ENHANCED LOW-LEVEL WARM ADVECTION APPEARS TO HAVE BEEN A
   SIGNIFICANT CONTRIBUTOR TO A SUSTAINED CLUSTER OF THUNDERSTORMS NOW
   PROGRESSING ACROSS PARTS OF SOUTHEASTERN NEBRASKA INTO NORTHEASTERN
   KANSAS.  HOWEVER...ACTIVITY APPEARS TO BE IN THE PROCESS OF
   DIMINISHING IN RESPONSE TO WEAKENING FORCING FOR ASCENT...AND IT IS
   NOT YET CLEAR WHETHER INHIBITION FOR DOWNSTREAM BOUNDARY LAYER
   PARCELS WILL WEAKEN ENOUGH TO ALLOW FOR SUSTAINED NEW STORM
   DEVELOPMENT ALONG THE REMNANT COLD POOL.

   OTHERWISE...FORCING FOR LARGE-SCALE ASCENT TO SUPPORT THUNDERSTORM
   DEVELOPMENT PRIOR TO SOMETIME THIS EVENING OR OVERNIGHT REMAINS
   UNCLEAR.  OROGRAPHIC FORCING NEAR THE BLACK HILLS COULD PROVIDE THE
   FOCUS/FORCING FOR ISOLATED STORM DEVELOPMENT.  MID-LEVEL INHIBITION
   MAY REMAIN WEAK ENOUGH TO ALLOW FOR WIDELY SCATTERED THUNDERSTORMS
   TO THE SOUTH AND EAST OF THE BLACK HILLS.  IF THIS OCCURS...SHEAR
   BENEATH WEAK TO MODEST /20-30 KT/ NORTHWESTERLY MID-LEVEL FLOW MAY
   BE SUFFICIENT FOR SUPERCELLS...IN AN ENVIRONMENT CHARACTERIZED BY
   STEEP MID-LEVEL LAPSE RATES...PROVIDING SUPPORT FOR THE RISK OF
   LARGE HAIL AND LOCALIZED DAMAGING SURFACE GUSTS.

   AT LEAST SOMEWHAT BETTER POTENTIAL FOR THUNDERSTORM DEVELOPMENT
   APPEARS TO EXIST LATE THIS EVENING INTO THE OVERNIGHT HOURS.  THIS
   MAY BE AIDED BY WARM ADVECTION ASSOCIATED WITH A NOCTURNALLY
   STRENGTHENING SOUTHERLY LOW-LEVEL JET...ACROSS PARTS OF
   NEBRASKA/KANSAS...AND/OR PERHAPS FORCING WITH A SUBTLE PERTURBATION
   ON THE SOUTHERN FRINGE OF THE WESTERLIES...ACROSS THE BLACK HILLS
   REGION.

   ...LOWER GREAT LAKES INTO MID ATLANTIC REGION...
   DOWNSTREAM OF LOW AMPLITUDE UPPER TROUGHING...20-30 KT WESTERLY
   MID-LEVEL FLOW MAY CONTRIBUTE TO SOME ENHANCEMENT OF THUNDERSTORM
   DEVELOPMENT NEAR THE FRONT/LOW IN THE VICINITY OF LAKE ERIE...AND TO
   THE EAST OF THE CENTRAL APPALACHIANS.  LOW/MID-LEVEL LAPSE RATES ARE
   GENERALLY WEAK...AND SEASONABLY STRONG SURFACE HEATING APPEARS
   UNLIKELY.  FURTHERMORE...LOW-LEVEL WIND FIELDS ARE WEAK. 
   HOWEVER...HEAVY PRECIPITATION LOADING MAY BE ENOUGH TO CONTRIBUTE TO
   THE RISK FOR POTENTIALLY DAMAGING DOWNBURSTS IN SUSTAINED
   THUNDERSTORM ACTIVITY.  GREATEST POTENTIAL FOR THIS MAY BE NEAR AND
   TO THE LEE OF THE BLUE RIDGE LATE THIS AFTERNOON...IN ASSOCIATION
   WITH STRONGEST INSOLATION...BUT OVERALL SEVERE WEATHER POTENTIAL
   APPEARS LIKELY TO REMAIN MARGINAL IN NATURE.

   ..KERR/JIRAK.. 07/30/2016

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