{
  "$type": "site.standard.document",
  "bskyPostRef": {
    "cid": "bafyreifzvp3ehyhnxc4eqk7qf6hdim4gi46vri4lcmuhgkse7dlq63l72u",
    "uri": "at://did:plc:fkx2xbvcahvjzw7vhooen2bf/app.bsky.feed.post/3ml2ng3snd4i2"
  },
  "path": "/products/md/md0638.html",
  "publishedAt": "2026-05-04T21:41:02.000Z",
  "site": "https://www.spc.noaa.gov",
  "tags": [
    "Read more"
  ],
  "textContent": "MD 0638 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF THE MIDWEST AND SOUTHERN GREAT LAKES\n\n\n\n\n    Mesoscale Discussion 0638\n    NWS Storm Prediction Center Norman OK\n    0342 PM CDT Mon May 04 2026\n\n    Areas affected...portions of the Midwest and southern Great Lakes\n\n    Concerning...Severe potential...Watch possible\n\n    Valid 042042Z - 042245Z\n\n    Probability of Watch Issuance...40 percent\n\n    SUMMARY...Widely scattered to scattered thunderstorm development is\n    expected late this afternoon, with potential for severe/damaging\n    wind gusts and large hail. Watch issuance is possible for a portion\n    of the discussion area.\n\n    DISCUSSION...Prevailing southwesterly flow has yielded modest\n    moisture return across portions of the Midwest into the southern\n    Great Lakes region, with dewpoints climbing into the 40s/low-50s.\n    While a surface cold front remains displaced to the northwest,\n    expectation is for widely scattered to scattered strong to severe\n    thunderstorms to develop within the warm conveyor this afternoon as\n    convective temperatures are reached and remaining inhibition is\n    removed. A 700-mb speed max associated with an approaching shortwave\n    trough will help to promote 30-40 kts of effective bulk shear across\n    the region, with MLCAPE forecast in the 500-1250 J/kg range. This\n    will be sufficient to support storm organization into\n    multicells/clusters and perhaps transient supercell structures;\n    although, the lack stronger flow aloft and limited hodograph\n    elongation is likely to limit supercell intensity/persistence.\n\n    Dry mid-level air and well-mixed boundary layers (as sampled by\n    regional ACARS profiles and the 18z DVN observed sounding) will\n    support a risk for severe/damaging wind gusts. Large hail will also\n    be possible given modestly steep mid-level lapse rates (>7 C/km per\n    latest mesoanalysis). While a strengthening of 850 mb flow and some\n    accompanying increase in low-level hodograph curvature is expected\n    this evening (especially across northern Indiana and northwest Ohio\n    within the 21-00z time frame), the tornado threat remains uncertain\n    owing to the expectation for boundary layer moisture quality to\n    remain more limited across the region.\n\n    Thus, given the potential for these hazards, a Severe Thunderstorm\n    Watch is possible for a portion of the discussion area, particularly\n    from northeastern Illinois into northwestern Ohio where the\n    potential coverage of severe hazards appears greater.\n\n    ..Chalmers/Smith.. 05/04/2026\n\n    ...Please see www.spc.noaa.gov for graphic product...\n\n    ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...\n    MKX...DVN...\n\n    LAT...LON   40518958 40679037 41009087 41529106 42019081 42459004\n                42658882 42808808 42928668 42858577 42578475 42178393\n                41858341 41368312 40998314 40728341 40518462 40438591\n                40448725 40458834 40478912 40518958\n\n    MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH\n    MOST PROBABLE PEAK WIND GUST...55-70 MPH\n    MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN\n\n\n\nRead more",
  "title": "SPC MD 638"
}