May 18, 2022 2000 UTC Day 1 Convective Outlook
Updated: Wed May 18 19:58:47 UTC 2022 (20220518 2000Z Day 1 shapefile | 20220518 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20220518 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 104,786 3,827,826 Louisville, KY...Lexington-Fayette, KY...Pueblo, CO...Duluth, MN...Bowling Green, KY...
MARGINAL 248,605 17,188,188 Oklahoma City, OK...Nashville, TN...Tulsa, OK...Colorado Springs, CO...Minneapolis, MN...
Probabilistic Tornado Graphic
20220518 2000 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
5 % 11,292 1,269,171 Lexington-Fayette, KY...Richmond, KY...Frankfort, KY...Nicholasville, KY...Elizabethtown, KY...
2 % 34,934 2,409,155 Louisville, KY...Bowling Green, KY...Jeffersonville, IN...Hopkinsville, KY...Jeffersontown, KY...
Probabilistic Damaging Wind Graphic
20220518 2000 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 19,829 156,428 Liberal, KS...Woodward, OK...Guymon, OK...Lamar, CO...
15 % 93,167 3,645,775 Louisville, KY...Lexington-Fayette, KY...Pueblo, CO...Duluth, MN...Bowling Green, KY...
5 % 258,810 17,323,959 Oklahoma City, OK...Nashville, TN...Tulsa, OK...Colorado Springs, CO...Minneapolis, MN...
Probabilistic Large Hail Graphic
20220518 2000 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 % 65,386 3,461,459 Louisville, KY...Lexington-Fayette, KY...Duluth, MN...Bowling Green, KY...Enid, OK...
5 % 242,160 14,617,007 Oklahoma City, OK...Tulsa, OK...Colorado Springs, CO...Minneapolis, MN...St. Paul, MN...
   SPC AC 181958

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0258 PM CDT Wed May 18 2022

   Valid 182000Z - 191200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE UPPER MIDWEST...CENTRAL/SOUTHERN PLAINS...AND KENTUCKY...

   ...SUMMARY...
   A couple tornadoes along with scattered damaging winds and severe
   hail remain possible across Kentucky and vicinity late this
   afternoon and early evening. Scattered severe winds, a couple of
   which may be significant, may occur from southeast Colorado to the
   Kansas/Oklahoma border area from late afternoon into tonight.
   Isolated to scattered large hail and damaging winds are also
   possible across northeast/east-central Minnesota into northwest
   Wisconsin during the late afternoon to early evening.

   ...20Z Update...
   Have trimmed severe probabilities behind an MCV with associated
   small cluster of thunderstorms ongoing along the IN/KY border area.
   If this activity can become surface based, then it would pose a
   threat for damaging winds, hail, and perhaps a tornado. The
   potential for additional severe thunderstorms to develop on the
   southwest flank of the MCV in western/central KY remains unclear.
   See Mesoscale Discussion 812 for more details on the near-term
   severe threat across this area.

   Elsewhere, generally minor changes have been made to the outlook to
   account for latest observational trends and short-term model
   guidance. Still, overall forecast reasoning remains unchanged.
   Mesoscale Discussion 813 contains more information on the short-term
   severe risk across MN, while Mesoscale Discussion 814 details
   expected convective evolution across eastern CO and vicinity this
   afternoon. Mesoscale Discussion 815 has additional details on the
   isolated wind threat across north-central NE over the next couple of
   hours.

   ..Gleason.. 05/18/2022

   .PREV DISCUSSION... /ISSUED 1127 AM CDT Wed May 18 2022/

   ...KY vicinity to the MO/AR border...
   A pronounced MCV over southern IL will track east across the OH
   Valley towards the central Appalachians through this evening.
   Primary severe potential should eventually emanate out of the
   south-southwest flank of the MCV where some cloud breaks should
   support surface-based destabilization in tandem with a plume of low
   to mid 60s boundary-layer dew points spreading east. A fairly tight
   gradient in MLCAPE is anticipated from west to east by late
   afternoon. A couple supercells should develop in this time frame
   amid enhanced low to mid-level flow attendant to the MCV. A threat
   for all severe hazards is possible, although the overall spatial
   distribution will likely remain isolated and temporally confined, in
   addition to delays in low-level destabilization which could limit
   intensity. Some west/east-oriented clustering may linger during the
   evening, but the severe threat should wane after the MCV outpaces
   the plume of diurnal destabilization. 

   Farther west, isolated thunderstorm development will be possible
   this evening along the effective baroclinic zone near the MO/AR
   border. Forcing for ascent will be weak/shallow and confined to the
   front, so storm development/coverage is uncertain. However,
   mid-level lapse rates of 8-9 C/km, MLCAPE greater than 3000 J/kg,
   and mid-level flow near 40 kt will support a conditional threat for
   large hail and damaging winds. 

   ...Southeast CO to northern OK...
   A cluster of high-based storms appears probable across southeast CO
   by mid to late afternoon, immediately east of the mountains in a
   zone of weak upslope flow and strong surface heating/deep mixing.
   Rather deeply mixed, inverted-V thermodynamic profiles with DCAPE
   greater than 1200 J/kg, will favor strong downdrafts and the
   potential for a storm cluster with occasional severe outflow gusts
   of 60-75 mph from southeast CO into the OK Panhandle this evening.
   Guidance is fairly consistent that the MCS will impinge on a plume
   of richer low-level moisture arcing westward across northern OK.
   This should help sustain a convectively generated MCV and maintain
   the surface cold pool eastward along the southern KS/northern OK
   border area. At least an isolated severe wind and some hail risk
   should linger overnight in northern OK.

   ...Northeast/east-central MN and northwest WI...
   A shortwave trough near the ND/Manitoba border will progress towards
   the Upper Great Lakes through tonight. Attendant surface cyclone
   should largely track along the MN/Ontario border with a reinforcing
   cold front to its south-southwest sweeping east. Despite limited
   low-level moisture on the larger scale, a corridor of low to mid 50s
   surface dew points combined with abundant boundary-layer heating
   beneath steep mid-level lapse rates and cooling mid-level
   temperatures (colder than -20 C at 500 mb) will support MLCAPE
   approaching 1000 J/kg with minimal convective inhibition. Effective
   bulk shear of 40-50 kts with mainly straight hodographs and the
   modest buoyancy will be sufficient for at least a few supercells
   capable of large hail and isolated damaging winds. This threat will
   diminish rapidly after dusk.

   ...Central NE and far south-central SD...
   Convergence along the trailing portion of the aforementioned
   reinforcing cold front may be sufficient for isolated thunderstorms
   during the late afternoon to early evening. While buoyancy will be
   weak, adequate deep-layer shear and a steep low to mid-level lapse
   rate environment will support potential for isolated, marginally
   severe hail and wind.

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