Jul 26, 2016 0600 UTC Day 1 Convective Outlook
Updated: Tue Jul 26 05:16:41 UTC 2016 (20160726 1200Z Day 1 shapefile | 20160726 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160726 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 54,810 290,954 Rapid City, SD...Pierre, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...
MARGINAL 398,040 20,085,158 Washington, DC...Virginia Beach, VA...Lexington-Fayette, KY...Norfolk, VA...Greensboro, NC...
Probabilistic Tornado Graphic
20160726 1200 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
2 % 54,552 288,303 Rapid City, SD...Pierre, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...
Probabilistic Damaging Wind Graphic
20160726 1200 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
15 % 54,916 289,923 Rapid City, SD...Pierre, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...
5 % 402,373 20,958,568 Washington, DC...Virginia Beach, VA...Minneapolis, MN...Norfolk, VA...Greensboro, NC...
Probabilistic Large Hail Graphic
20160726 1200 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
15 % 54,721 290,588 Rapid City, SD...Pierre, SD...Spearfish, SD...Rapid Valley, SD...Sturgis, SD...
5 % 296,259 5,374,604 Sioux Falls, SD...Fargo, ND...Duluth, MN...Sioux City, IA...Plymouth, MN...
   SPC AC 260516

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1216 AM CDT TUE JUL 26 2016

   VALID 261200Z - 271200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SD AND
   NEBRASKA...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE NORTHERN
   AND CENTRAL PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM KY INTO THE MIDDLE
   ATLANTIC...

   ...SUMMARY...
   THE GREATEST POTENTIAL FOR SEVERE THUNDERSTORMS ON TUESDAY WILL BE
   ACROSS PORTIONS OF SOUTH DAKOTA AND NEBRASKA DURING THE AFTERNOON
   AND EVENING. MORE ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE ON
   TUESDAY ELSEWHERE ACROSS PORTIONS OF THE NORTHERN AND CENTRAL GREAT
   PLAINS EASTWARD TO UPPER MICHIGAN...AND ACROSS PARTS OF THE
   MID-ATLANTIC AND CENTRAL APPALACHIANS.

   VERY MOIST AIR MASS WILL ENCOMPASS MUCH OF THE ERN CONUS TUESDAY AND
   SCT THUNDERSTORMS WILL BE COMMON DURING THE AFTERNOON AND EARLY
   EVENING FROM THE ROCKIES...EAST TO THE MIDDLE ATLANTIC COAST.  THERE
   ARE TWO MAIN AREAS WHERE ROBUST THUNDERSTORMS MAY PRODUCE A SEVERE
   THREAT...THE NRN/CNTRL PLAINS AND THE MIDDLE ATLANTIC AND CNTRL
   APPALACHIANS.

   1.  NORTHERN AND CENTRAL PLAINS.  SEVERAL WEAK MID-LEVEL
   DISTURBANCES WILL PROGRESS ACROSS THE NRN ROCKIES INTO THE PLAINS
   DURING THE UPCOMING DAY1 PERIOD.  THESE FEATURES WILL ENSURE THE
   RIDGE REMAINS FLAT ACROSS MT/WY INTO THE DAKOTAS.  WV IMAGERY
   DEPICTS ONE WELL DEFINED DISTURBANCE OVER SCNTRL MT AT 26/05Z.  THIS
   FEATURE SHOULD DRIFT TOWARD THE NRN BLACK HILLS REGION BY LATE
   AFTERNOON ENHANCING TSTM ACTIVITY BY PEAK HEATING.  CONVECTION IS
   EXPECTED TO INITIATE OVER BOTH THE BLACK HILLS AND ALONG ADJACENT
   E-W SFC BOUNDARY...JUST NORTH OF LEE SFC LOW.  THIS ACTIVITY SHOULD
   MATURE WITHIN A MODESTLY UNSTABLE AIR MASS CHARACTERIZED BY SBCAPE
   ON THE ORDER OF 3000 J/KG AND SFC-6KM BULK SHEAR...MORE THAN
   ADEQUATE FOR ORGANIZED ROTATING UPDRAFTS.  CURRENT THINKING IS
   INITIAL ACTIVITY MAY BE SUPERCELLULAR IN NATURE BUT STORM MERGERS
   DURING THE LLJ INTENSIFICATION PHASE AFTER DARK MAY RESULT IN AN
   MCS-TYPE COMPLEX PROPAGATING SEWD TOWARD CNTRL NEBRASKA.  HAIL AND
   WIND ARE THE MAIN THREATS.

   2.  MIDDLE ATLANTIC AND CENTRAL APPALACHIANS.  20KT 500MB WLY FLOW
   IS EXPECTED TO PERSIST AT THE LATITUDE OF THE MRGL RISK FROM
   KY...EWD ACROSS VA TUESDAY.  STRONG BOUNDARY-LAYER HEATING WILL
   CONTRIBUTE TO DESTABILIZATION SUFFICIENT FOR TSTM DEVELOPMENT BY 18Z
   ACROSS THIS REGION AS SFC TEMPERATURES SOAR INTO THE LOWER 90S.  ANY
   UPDRAFTS THAT FORM WITHIN THIS HIGH PW AIR MASS...ON THE ORDER OF 2
   INCHES...COULD CERTAINLY PRODUCE GUSTY DOWNBURSTS...POTENTIALLY
   REACHING SEVERE LEVELS AT A LOCAL LEVEL.  CONVECTION WILL BE
   STRONGLY DIURNAL AND SHOULD WEAKEN WITH LOSS OF DAYTIME HEATING.

   ..DARROW/LEITMAN.. 07/26/2016

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z