Aug 28, 2016 1630 UTC Day 1 Convective Outlook
Updated: Sun Aug 28 16:31:02 UTC 2016 (20160828 1630Z Day 1 shapefile | 20160828 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160828 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 34,001 686,613 Fargo, ND...Grand Forks, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...
MARGINAL 218,392 26,992,526 Nashville, TN...Cleveland, OH...Minneapolis, MN...Pittsburgh, PA...Toledo, OH...
Probabilistic Tornado Graphic
20160828 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
5 % 15,684 420,849 Fargo, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...Fergus Falls, MN...
2 % 34,439 381,579 Grand Forks, ND...Brainerd, MN...Alexandria, MN...Wahpeton, ND...Valley City, ND...
Probabilistic Damaging Wind Graphic
20160828 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
15 % 15,604 247,426 Fergus Falls, MN...Bemidji, MN...Wahpeton, ND...
5 % 225,652 25,311,791 Nashville, TN...Cleveland, OH...Pittsburgh, PA...Toledo, OH...Buffalo, NY...
Probabilistic Large Hail Graphic
20160828 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
15 % 34,379 690,996 Fargo, ND...Grand Forks, ND...Moorhead, MN...West Fargo, ND...West Fargo, MN...
5 % 65,875 4,233,162 Minneapolis, MN...St. Paul, MN...Duluth, MN...Bloomington, MN...Plymouth, MN...
   SPC AC 281631

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 AM CDT SUN AUG 28 2016

   VALID 281630Z - 291200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MIDWEST...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE DAKOTAS/UPPER
   MIDWEST...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE LOWER GREAT
   LAKES/NORTHEAST STATES...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE TN VALLEY/SOUTHERN
   APPALACHIANS...

   ...SUMMARY...
   SEVERE STORMS APPEAR MOST PROBABLE ACROSS PARTS OF THE UPPER MIDWEST
   LATE THIS AFTERNOON AND EVENING...WHILE OTHER STRONG STORMS MAY
   OCCUR ACROSS THE NORTHEAST STATES AND TENNESSEE VALLEY.

   ...UPPER MIDWEST...
   AN UPPER TROUGH MOVING FROM ALBERTA TOWARD SASKATCHEWAN AT MIDDAY
   WILL CONTINUE EAST-NORTHEASTWARD...WITH WEAK HEIGHT RISES AND
   GENERALLY WEAKENING LARGER-SCALE FORCING EXPECTED DOWNSTREAM ACROSS
   THE DAKOTAS/MN INTO THIS EVENING. AN INCREASINGLY MOIST AIR MASS
   /60S F SURFACE DEWPOINTS/ WILL DEVELOP NORTHWARD PARTICULARLY ACROSS
   THE EASTERN DAKOTAS AND WESTERN/NORTHERN MN...TO THE SOUTH OF A
   NORTHWARD-SHIFTING WARM FRONT AND AHEAD OF A COLD FRONT THAT IS
   CURRENTLY PROGRESSING EASTWARD ACROSS EASTERN MT.

   AFOREMENTIONED WEAK/DETRIMENTAL LARGE-SCALE INFLUENCES AND
   INCREASING MID-LEVEL CAPPING SHOULD GENERALLY LIMIT STORM
   DEVELOPMENT ACROSS MUCH OF THE REGION THROUGH PEAK HEATING.
   HOWEVER...ISOLATED STORMS MAY FORM ALONG THE EASTWARD-MOVING COLD
   FRONT IMPINGING ON THE WESTERN PERIPHERY OF RICHER BOUNDARY-LAYER
   MOISTURE ACROSS PARTS OF FAR NORTH-CENTRAL ND. A SUPERCELL OR TWO
   MAY DEVELOP HERE INTO NORTHEAST ND DURING THE EVENING...WITH ALL
   HAZARDS POSSIBLE.

   THE MOST PROBABLE SCENARIO MAY BE FOR STORMS TO DEVELOP/INCREASE
   AROUND AND AFTER SUNSET ACROSS NORTHWEST MN AND POSSIBLY EXTREME
   EASTERN ND NEAR THE WARM FRONT AS WARM-AIR ADVECTION INCREASES ASIDE
   FROM A GLANCING INFLUENCE OF A CANADIAN PRAIRIES SHORTWAVE TROUGH.
   IN THE PRESENCE OF STEEP LAPSE RATES/AMPLE BUOYANCY...ALL SEVERE
   HAZARDS INCLUDING LARGE HAIL AND SOME TORNADO RISK WILL EXIST WITH
   THIS INITIAL DEVELOPMENT. SUBSEQUENTLY...AT LEAST A RELATIVELY
   SMALL-SCALE DAMAGING WIND RISK MAY ALSO EVOLVE LATER IN THE EVENING
   INTO THE OVERNIGHT AS STORMS MERGE/SPREAD EAST-SOUTHEASTWARD ACROSS
   NORTHERN MN.

   ...LOWER GREAT LAKES/NORTHEAST STATES...
   A PLUME OF MID TO UPPER 60S SURFACE DEW POINTS EXISTS DOWNSTREAM OF
   THE LOWER GREAT LAKES. BOUNDARY-LAYER HEATING OF THIS AIR MASS WILL
   SUPPORT MODERATE BUOYANCY BY AFTERNOON. GLANCING MID-LEVEL HEIGHT
   FALLS ASSOCIATED WITH THE EASTWARD-MOVING SHORTWAVE TROUGH OVER
   NORTHERN ONTARIO SHOULD SUPPORT ISOLATED TO WIDELY SCATTERED STORMS
   FORMING ALONG A WEAK COLD FRONT AND PRE-FRONTAL AREAS OF CONFLUENCE.
   THE STRONGEST DEEP-LAYER SPEED SHEAR WILL EXIST ACROSS NORTHERN
   NY/VT AND THUS HAVE EXPANDED MARGINAL RISK PROBABILITIES FOR LOCALLY
   DAMAGING WIND GUSTS.

   ...TN/KY AND ADJACENT APPALACHIANS...
   WATER VAPOR FEATURES A RELATIVELY SUBTLE MID-LEVEL DISTURBANCE OVER
   CENTRAL PORTIONS OF KY/TN THIS AFTERNOON...WHILE 12Z OBSERVED
   SOUNDINGS FROM NASHVILLE AND WILMINGTON OH SAMPLED RELATIVELY COOL
   MID-LEVEL TEMPERATURES AT AROUND -8C AT 500 MB. AS BOUNDARY-LAYER
   DESTABILIZATION OCCURS THIS AFTERNOON AS LOW-LEVEL LAPSE RATES
   STEEPEN...THUNDERSTORMS SHOULD INCREASE/INTENSIFY ACROSS THE REGION
   AND SUBSEQUENTLY DRIFT GENERALLY WESTWARD. DOWNBURSTS CAPABLE OF
   LOCALIZED DAMAGING WINDS WILL BE POSSIBLE WITH THE STRONGEST
   UPDRAFTS/DOWNDRAFTS THIS AFTERNOON THROUGH EARLY EVENING.

   ..GUYER/PICCA.. 08/28/2016

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