May 12, 2022 0600 UTC Day 1 Convective Outlook
Updated: Thu May 12 05:56:38 UTC 2022 (20220512 1200Z Day 1 shapefile | 20220512 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20220512 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 116,515 6,609,579 Omaha, NE...Minneapolis, MN...St. Paul, MN...Lincoln, NE...Sioux Falls, SD...
SLIGHT 142,711 3,752,755 Des Moines, IA...Rochester, MN...Duluth, MN...Ames, IA...West Des Moines, IA...
MARGINAL 282,239 10,970,118 Kansas City, MO...New Orleans, LA...Wichita, KS...Baton Rouge, LA...Lubbock, TX...
Probabilistic Tornado Graphic
20220512 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
10 % 19,229 402,440 Moorhead, MN...Watertown, SD...Fergus Falls, MN...Wahpeton, ND...
5 % 47,799 1,410,628 Sioux Falls, SD...Fargo, ND...St. Cloud, MN...Aberdeen, SD...Willmar, MN...
2 % 52,104 2,767,237 Sioux City, IA...Plymouth, MN...Brooklyn Park, MN...Eden Prairie, MN...Coon Rapids, MN...
Probabilistic Damaging Wind Graphic
20220512 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
45 % 27,289 671,564 Sioux Falls, SD...Watertown, SD...Brookings, SD...Mitchell, SD...Yankton, SD...
30 % 82,480 5,868,124 Omaha, NE...Minneapolis, MN...St. Paul, MN...Lincoln, NE...Fargo, ND...
15 % 87,991 3,302,009 Des Moines, IA...Rochester, MN...Ames, IA...West Des Moines, IA...Woodbury, MN...
5 % 237,944 10,140,445 Kansas City, MO...New Orleans, LA...Wichita, KS...Baton Rouge, LA...Lubbock, TX...
Probabilistic Large Hail Graphic
20220512 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
SIG SEVERE 76,770 1,045,564 Fargo, ND...Grand Island, NE...Moorhead, MN...Kearney, NE...Norfolk, NE...
30 % 49,790 856,869 Fargo, ND...Grand Island, NE...Moorhead, MN...Kearney, NE...Norfolk, NE...
15 % 209,630 9,507,890 Omaha, NE...Minneapolis, MN...St. Paul, MN...Lincoln, NE...Des Moines, IA...
5 % 239,873 7,035,266 Kansas City, MO...Wichita, KS...Lubbock, TX...Overland Park, KS...Kansas City, KS...
   SPC AC 120556

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1256 AM CDT Thu May 12 2022

   Valid 121200Z - 131200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
   THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

   ...SUMMARY...
   Well-organized severe storms are expected to evolve from the eastern
   Dakotas and Minnesota southward into the central Plains Today. Very
   large hail and severe gusts are expected, along with the potential
   for at least a few tornadoes.

   ...Synopsis...
   A compact, negatively tilted trough will eject into the northern
   Plains today, supporting the intensification of a surface low near
   the NE/SD border, which will track north-northeast through the day.
   Ample low-level moisture will advect ahead of the surface low across
   the warm sector and will be overspread by cold temperatures aloft,
   promoting large amounts of buoyancy across the northern Plains/Upper
   Mississippi Valley. Modest veering/strengthening of the vertical
   wind profile and deep-layer ascent amid large buoyancy will support
   widespread, vigorous convective development capable of all severe
   hazards.

   ...Northern Great Plains into the Upper Mississippi Valley...
   Elevated convection, perhaps in the form of transient supercells,
   may be ongoing at the start of the period across portions of the
   Dakotas. Here, 1500+ J/kg MUCAPE (mainly above 700 mb) will be in
   place given the presence of 7-8 C/km mid-level lapse rates. 40 kt
   850 mb flow veering while increasing to near 70 kts at 500 mb will
   contribute to 50-60 kts of effective bulk shear, which may support
   organized, sustained elevated storms with a severe-hail threat given
   the aforementioned buoyancy.

   Later in the afternoon and evening, the surface low will strengthen
   modestly while translating north-northeastward towards the Upper
   Mississippi Valley. Strengthening southerly low-level flow will
   advect a high-theta-e airmass northward across the eastern northern
   Plains states, with upper 60s to low 70s F dewpoints likely becoming
   widespread ahead of a surface cold front. As 8-9 C/km mid-level
   lapse rates overspread a deepening, mixing boundary layer through
   the afternoon, 3000+ J/kg SBCAPE will become common. Strong forcing
   for ascent will support widespread convection developing ahead of
   the front as CINH erodes. Transient supercells are expected to be
   the initial mode of convection, posing a threat for very large hail
   (given the high magnitude of CAPE in the hail-growth zone). However,
   mid-level winds should have a considerable parallel component of
   flow to the boundary, and storms are expected to quickly form a
   squall line a few hours after initiation. At that point, numerous
   severe gusts should occur, with large hail becoming a secondary
   threat.

   Closer to the surface low in eastern SD into western MN, low-level
   winds will be backed more, with greater low-level
   veering/strengthening with height supporting enlarged 0-3km
   hodographs and 200+ m2/s2 of effective SRH. Given a potentially
   strongly unstable environment, at least a few tornadoes are
   possible, especially if any sustained, discrete storms can develop
   just ahead of the surface low. Otherwise, a couple of tornadoes may
   still occur with embedded mesovortices associated with linear
   convection that can favorably interact with the warm front.

   ..Southern High Plains...
   Deep-layer ascent will be largely displaced farther north, with the
   main source of ascent for convection being weak convergence along a
   diffuse dryline. By afternoon peak heating, very isolated
   thunderstorms may develop ahead of the dryline. Modest deep-layer
   shear suggests that transient supercells may be the predominant mode
   of convection, with large hail and damaging gusts possible with any
   sustained storm. However, the very sparse expected coverage warrants
   only Category 1/Marginal probabilities at this time.

   ...Portions of eastern Louisiana into central Mississippi...
   Deep-layer northeasterly flow will prevail across the Southeast
   given the presence of a near-stationary upper low just east of the
   Florida Peninsula. By afternoon peak heating, multicellular storm
   clusters are expected to develop in a moist, but well-mixed boundary
   layer. Steep low-level lapse rates will contribute to 2000+ j/kg
   MLCAPE. As thunderstorms progress in this environment, adequate
   evaporative cooling within the mixed boundary layer will promote at
   least a couple of damaging gusts, warranting Category 1/Marginal
   probabilities.

   ..Squitieri/Darrow.. 05/12/2022

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