Apr 4, 2023 1730 UTC Day 2 Convective Outlook
Updated: Tue Apr 4 17:29:36 UTC 2023 (20230404 1730Z Day 2 shapefile | 20230404 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20230404 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 213,306 43,801,764 Chicago, IL...Detroit, MI...Indianapolis, IN...Columbus, OH...Memphis, TN...
SLIGHT 178,199 18,856,227 Milwaukee, WI...St. Louis, MO...Pittsburgh, PA...Buffalo, NY...Rochester, NY...
MARGINAL 226,684 25,267,048 Houston, TX...Corpus Christi, TX...Madison, WI...Baton Rouge, LA...Jackson, MS...
Probabilistic Tornado Graphic
20230404 1730 UTC Day 2 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 2 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 93,333 23,070,775 Chicago, IL...Detroit, MI...Indianapolis, IN...Toledo, OH...Fort Wayne, IN...
10 % 108,811 26,974,797 Chicago, IL...Detroit, MI...Indianapolis, IN...Cleveland, OH...Toledo, OH...
5 % 175,761 28,865,307 Columbus, OH...Memphis, TN...Milwaukee, WI...Nashville, TN...St. Louis, MO...
2 % 162,472 11,891,865 Madison, WI...Shreveport, LA...Little Rock, AR...Rockford, IL...Green Bay, WI...
Probabilistic Damaging Wind Graphic
20230404 1730 UTC Day 2 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 2 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 213,131 43,788,247 Chicago, IL...Detroit, MI...Indianapolis, IN...Columbus, OH...Memphis, TN...
15 % 177,883 18,892,388 Milwaukee, WI...St. Louis, MO...Pittsburgh, PA...Buffalo, NY...Rochester, NY...
5 % 227,535 25,385,036 Houston, TX...Corpus Christi, TX...Madison, WI...Baton Rouge, LA...Jackson, MS...
Probabilistic Large Hail Graphic
20230404 1730 UTC Day 2 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 2 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 79,126 20,295,507 Chicago, IL...Detroit, MI...Fort Wayne, IN...Grand Rapids, MI...Naperville, IL...
30 % 92,952 23,429,718 Chicago, IL...Detroit, MI...Indianapolis, IN...Toledo, OH...Fort Wayne, IN...
15 % 232,753 30,391,883 Columbus, OH...Memphis, TN...Milwaukee, WI...Nashville, TN...Cleveland, OH...
5 % 205,092 23,573,672 Houston, TX...Pittsburgh, PA...Corpus Christi, TX...Buffalo, NY...Madison, WI...
   SPC AC 041729

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 PM CDT Tue Apr 04 2023

   Valid 051200Z - 061200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
   OHIO RIVER VALLEY TO THE GREAT LAKES REGION...

   ...SUMMARY...
   Scattered severe storms posing a risk for strong tornadoes and large
   hail are expected in a corridor across eastern Illinois through
   Lower Michigan Wednesday, with organizing clusters or lines of
   storms accompanied by potentially damaging wind gusts, and a few
   tornadoes across the Ohio Valley vicinity.

   ...Synopsis...
   Recent water-vapor imagery continues to depict a robust upper wave
   over the central Rockies with an accompanying surface low noted in
   mid-morning surface observations across the central Plains. Guidance
   continues to show reasonably good agreement in the evolution of
   these features over the next 48 hours as the upper wave ejects into
   the Plains and the surface low tracks northeastward through the
   Upper Great Lakes region by late Wednesday. A trailing cold front is
   expected to impinge on a broad warm sector beginning late tonight as
   it migrates southeast through the Midwest, mid-MS River Valley, and
   TX Gulf coast through the day Wednesday. Strong to severe
   thunderstorms will likely be ongoing at the beginning of the period
   along much of the cold front, and more organized cells and/or
   clusters may persist into the afternoon hours given the strongly
   sheared environment and diurnal warming/destabilization. Locations
   that see weakening of early-morning convection will likely see
   re-intensification either along the cold or residual outflow
   boundaries by late afternoon. Given the broad warm sector (featuring
   60+ F dewpoints) and strong flow over the region, organized
   convection appears likely across a large swath of the Midwest to
   south-central CONUS. One notable trend for this update is a westward
   shift in probabilities driven by a slower eastward progression of
   the synoptic wave/surface low that has consistently emerged in
   recent global and mesoscale guidance.

   ...IL to OH and lower MI...
   Confidence in the severe threat remains highest across portions of
   the Midwest. Open warm sector convection may be ongoing by 12 UTC
   across parts of eastern MO/IL and will propagate into parts of IN,
   OH, and lower MI through the day. Poleward moisture advection in the
   wake of morning convection will maintain a buoyant air mass prior to
   the frontal passage in the late morning/afternoon when a second
   round of storms appears likely. The combination of the mid-level jet
   max aloft and strong low-level pressure gradient winds will result
   in a strongly sheared environment featuring effective bulk shear
   values near 50s knots and 150-200 m2/s2 of 0-1 km SRH. This
   kinematic environment will support a tornado threat, including the
   potential for a strong tornado, especially if more discrete storm
   modes can be realized (though it is unclear if boundary-relative
   storm motions and deep-layer shear vectors will be sufficient to
   maintain discrete modes given considerable along-boundary mean
   flow). Regardless, the strong low-level flow will support the
   potential for damaging to severe winds. 

   ...Middle MS and lower OH River Valleys...
   Forcing for ascent along the middle MS and lower OH River Valleys is
   expected to diminish through the day as stronger synoptic ascent
   becomes increasingly displaced to the north/northeast. Strong flow
   aloft on the southern periphery of the jet max will support
   elongated hodographs, which when coupled with 1500-2000 J/kg MLCAPE
   and residual ascent along the slowing cold front, will likely be
   favorable for semi-discrete cells to clusters with an attendant
   threat for large hail, damaging winds, and perhaps a tornado.

   ..Moore/Jewell.. 04/04/2023

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