Jul 19, 2019 1300 UTC Day 1 Convective Outlook
Updated: Fri Jul 19 12:36:24 UTC 2019 (20190719 1300Z Day 1 shapefile | 20190719 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190719 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 25,536 1,236,888 Eau Claire, WI...St. Cloud, MN...Wausau, WI...Andover, MN...Elk River, MN...
ENHANCED 59,913 5,013,685 Minneapolis, MN...St. Paul, MN...Green Bay, WI...Bloomington, MN...Plymouth, MN...
SLIGHT 79,387 6,128,895 Milwaukee, WI...Grand Rapids, MI...Lansing, MI...Flint, MI...Rochester, MN...
MARGINAL 286,682 24,901,216 Detroit, MI...Cleveland, OH...Toledo, OH...Buffalo, NY...Madison, WI...
Probabilistic Tornado Graphic
20190719 1300 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
SIG SEVERE 28,384 3,570,391 Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
15 % 9,996 596,768 St. Cloud, MN...Elk River, MN...Forest Lake, MN...Ham Lake, MN...Sartell, MN...
10 % 31,421 3,911,279 Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
5 % 52,049 2,128,846 Green Bay, WI...Appleton, WI...Oshkosh, WI...Manitowoc, WI...Winona, MN...
2 % 113,529 16,538,370 Detroit, MI...Milwaukee, WI...Cleveland, OH...Toledo, OH...Buffalo, NY...
Probabilistic Damaging Wind Graphic
20190719 1300 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
SIG SEVERE 37,422 4,590,641 Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
45 % 31,845 1,285,072 Eau Claire, WI...Wausau, WI...Andover, MN...Elk River, MN...Lino Lakes, MN...
30 % 43,866 4,611,433 Minneapolis, MN...St. Paul, MN...Green Bay, WI...Bloomington, MN...Plymouth, MN...
15 % 88,724 6,480,358 Milwaukee, WI...Grand Rapids, MI...Lansing, MI...Flint, MI...Rochester, MN...
5 % 282,425 24,818,295 Detroit, MI...Cleveland, OH...Toledo, OH...Buffalo, NY...Madison, WI...
Probabilistic Large Hail Graphic
20190719 1300 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 29,920 4,068,936 Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
30 % 16,311 3,366,113 Minneapolis, MN...St. Paul, MN...Bloomington, MN...Plymouth, MN...Brooklyn Park, MN...
15 % 66,093 3,204,015 Green Bay, WI...Rochester, MN...Appleton, WI...Eau Claire, WI...Lakeville, MN...
5 % 227,737 11,530,325 Detroit, MI...Milwaukee, WI...Grand Rapids, MI...Sioux Falls, SD...Warren, MI...
   SPC AC 191236

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0736 AM CDT Fri Jul 19 2019

   Valid 191300Z - 201200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS EAST-CENTRAL MN
   AND NORTHERN WI...

   ...SUMMARY...
   A regional outbreak of severe thunderstorms with strong tornadoes
   and potentially widespread significant wind damage may occur from
   central Minnesota across northern Wisconsin during the mid-afternoon
   to evening.

   ...Upper Midwest/Great Lakes...
   Upgrading to Moderate Risk this outlook for the potential threats of
   multiple strong tornadoes and a derecho later this afternoon and
   evening. CAPE/shear/SRH parameter space in this region is forecast
   to be exceptionally rare for mid July amid a predominately zonal
   flow regime across the northern states.

   A convective cluster is ongoing across north-central SD aided by
   warm/moist advection around 700 mb along a pronounced baroclinic
   zone. 00Z CAM guidance had a decent handle on this activity earlier
   this morning and are consistent with a decaying trend through late
   morning as advection shifts east amid pronounced MLCIN as sampled by
   the 12Z Aberdeen sounding. There is a low confidence scenario that a
   strong enough cold pool is becoming established with this early-day
   cluster such that total decay does not occur. If this occurs, robust
   boundary-layer heating downstream may be sufficient for an
   increasing threat during the afternoon of strong to severe wind
   gusts. This could still yield a scattered to widespread damaging
   wind scenario, albeit in an earlier time frame than progged by
   guidance.

   The more probable scenario is for an extremely unstable air mass
   (MLCAPE > 4000 J/kg) to become established to from southeast SD
   through central/southern WI as the elevated mixed-layer overspreads
   surface dew points rising into the mid to upper 70s. A surface
   cyclone over central SD should track towards the Twin Cities through
   early evening. Strong low-level convergence near/northeast of this
   cyclone along the warm front should sustain surface-based storm
   development across central into east-central MN. Once initiation
   occurs, intense supercells will develop rapidly, with an attendant
   threat for all severe hazards including strong tornadoes amid 50-60
   kt effective shear and 0-3 km SRH > 300 m2/s2. The very warm/moist
   thermodynamic profiles will also support generation of strong cold
   pools which should eventually yield a bowing, forward-propagating
   MCS across northern WI into parts of northern Lower and Upper MI.
   Strength of the vertical shear suggests the potential for intense
   bowing segments capable of yielding a derecho with significant
   severe wind gusts.

   ...Lower Great Lakes...
   An MCV progressing east over the Lower Great Lakes this afternoon
   should provide enough lift for scattered thunderstorms development.
   Air mass over the region will be moderately to strongly unstable but
   modestly sheared. Expectation is for predominantly multicellular,
   outflow-dominant storms capable of isolated damaging wind gusts.

   ...SD tonight...
   Another round of 700-mb warm/moist advection will occur tonight
   within a tight baroclinic zone well north of a surface front arcing
   across NE into northeast WY. Large elevated buoyancy and strong
   effective shear will support a risk for isolated large hail. The
   risk for severe wind will likely be tempered by a more stable
   sub-cloud layer in the second convective round.

   ..Grams/Gleason.. 07/19/2019

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