Jun 17, 2018 0600 UTC Day 1 Convective Outlook
Updated: Sun Jun 17 05:39:34 UTC 2018 (20180617 1200Z Day 1 shapefile | 20180617 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180617 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 101,055 6,503,704 Minneapolis, MN...St. Paul, MN...Sioux Falls, SD...Rochester, MN...Sioux City, IA...
MARGINAL 145,312 3,484,378 Green Bay, WI...Duluth, MN...Appleton, WI...Waterloo, IA...Oshkosh, WI...
Probabilistic Tornado Graphic
20180617 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 % 118,298 4,262,421 Minneapolis, MN...St. Paul, MN...Green Bay, WI...Duluth, MN...Plymouth, MN...
Probabilistic Damaging Wind Graphic
20180617 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
5 % 245,856 10,128,370 Minneapolis, MN...St. Paul, MN...Sioux Falls, SD...Green Bay, WI...Rochester, MN...
Probabilistic Large Hail Graphic
20180617 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 % 98,801 6,423,233 Minneapolis, MN...St. Paul, MN...Sioux Falls, SD...Rochester, MN...Sioux City, IA...
5 % 149,127 3,717,096 Green Bay, WI...Duluth, MN...Appleton, WI...Waterloo, IA...Oshkosh, WI...
   SPC AC 170539

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1239 AM CDT Sun Jun 17 2018

   Valid 171200Z - 181200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
   PLAINS TO THE UPPER GREAT LAKES...

   ...SUMMARY...
   The risk for Isolated severe thunderstorms appears greatest from the
   central High Plains to the upper Great Lakes.

   ...Central High Plains to Upper Great Lakes...

   Large-scale pattern is not expected to change appreciably through
   the upcoming day1 period as a dominant upper ridge should remain
   anchored over the TN/OH Valley region. While several disturbances
   are expected to eject across the Four Corners into the upper Great
   Lakes, latest model guidance suggests heights may actually rise
   along a corridor from the central High Plains into the upper MS
   Valley during the day.

   Early in the period scattered thunderstorms should be ongoing along
   the cool side of a frontal zone from the NE Panhandle, northeast
   into the upper Great Lakes region. This early-day activity is
   expected to contribute to a slight southward push to the boundary
   with an early afternoon frontal position expected to extend from the
   western part of Lake Superior to northeast CO. In the absence of
   meaningful large-scale ascent, it appears surface heating along the
   boundary will prove necessary for robust updrafts. Seasonally high
   PW values (1.5-2") should extend along the frontal corridor where
   CINH is expected to be weak/negligible by peak heating. For these
   reasons it appears scattered thunderstorms will once again evolve
   along the northwestern periphery of the aforementioned ridge where
   modest mid-level flow/bulk shear should prove supportive of
   multi-cell clusters and perhaps a few supercells. Convection will be
   modulated by diurnal processes and possibly a weak disturbance over
   the central Plains during the latter half of the period. Hail/wind
   are the primary threats with this activity.

   ..Darrow/Elliott.. 06/17/2018

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