Jul 10, 2021 0100 UTC Day 1 Convective Outlook
Updated: Sat Jul 10 00:59:29 UTC 2021 (20210710 0100Z Day 1 shapefile | 20210710 0100Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20210710 0100 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 96,947 3,831,940 Kansas City, MO...Omaha, NE...Lincoln, NE...Kansas City, KS...Independence, MO...
SLIGHT 146,190 8,859,807 St. Louis, MO...Des Moines, IA...Overland Park, KS...Cedar Rapids, IA...Topeka, KS...
MARGINAL 188,418 30,941,949 New York, NY...Philadelphia, PA...Virginia Beach, VA...Newark, NJ...Norfolk, VA...
Probabilistic Tornado Graphic
20210710 0100 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 % 84,987 4,497,887 Kansas City, MO...Omaha, NE...Lincoln, NE...Des Moines, IA...Kansas City, KS...
2 % 96,055 5,924,213 St. Louis, MO...Overland Park, KS...Topeka, KS...Springfield, IL...Olathe, KS...
Probabilistic Damaging Wind Graphic
20210710 0100 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 100,140 3,115,807 Kansas City, MO...Omaha, NE...Lincoln, NE...Kansas City, KS...Lawrence, KS...
30 % 97,456 4,008,381 Kansas City, MO...Omaha, NE...Lincoln, NE...Kansas City, KS...Independence, MO...
15 % 146,745 8,700,446 St. Louis, MO...Des Moines, IA...Overland Park, KS...Cedar Rapids, IA...Topeka, KS...
5 % 187,620 30,602,250 New York, NY...Philadelphia, PA...Virginia Beach, VA...Newark, NJ...Norfolk, VA...
Probabilistic Large Hail Graphic
20210710 0100 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 67,538 1,274,831 Omaha, NE...St. Joseph, MO...Council Bluffs, IA...Bellevue, NE...North Platte, NE...
30 % 9,946 18,590 No Major Population Center in Risk Area
15 % 211,029 11,190,214 Kansas City, MO...Omaha, NE...St. Louis, MO...Lincoln, NE...Des Moines, IA...
5 % 211,233 32,332,149 New York, NY...Philadelphia, PA...Virginia Beach, VA...Newark, NJ...Norfolk, VA...
   SPC AC 100059

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0759 PM CDT Fri Jul 09 2021

   Valid 100100Z - 101200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE CENTRAL PLAINS AND LOWER TO MID MISSOURI VALLEY...

   ...SUMMARY...
   Thunderstorms associated with wind damage and large hail will be
   likely across parts of the central and northern Plains
   east-southeastward into the mid to upper Mississippi Valley tonight.
   An isolated tornado threat may also develop across parts of the
   lower to mid Missouri Valley tonight. Storms with marginally severe
   hail and wind gusts will be possible this evening along the Eastern
   Seaboard.

   ...Central and Northern Plains/Lower to Mid Missouri Valley/Mid to
   Upper Mississippi Valley...
   A positively-titled upper-level trough will dig east-southeastward
   into the northern High Plains tonight. At the surface, a cold front
   will advance southward across the central High Plains as a low moves
   across the central Plains. The low will track east-northeastward
   along a quasi-stationary front extending eastward into the mid to
   upper Mississippi Valley. Surface dewpoints along and to the north
   of the front are generally in the lower to mid 70s F, which is
   contributing to strong to extreme instability. The RAP is estimating
   MLCAPE to be as high as 4000 to 5000 J/kg from central Nebraska
   east-southeastward into northwest Missouri. 

   Further to the west, moderate instability is in place across the
   central High Plains where scattered strong to severe thunderstorms
   are ongoing. MLCAPE is estimated to be in the 1500 to 2500 J/kg
   range from eastern Wyoming into southwestern South Dakota and
   western Nebraska. This combined with 0-6 km shear in the 50 to 65 kt
   range and 850 to 500 mb lapse rates exceeding 8.0 C/km will be
   favorable for supercells with large hail. Hailstones of greater than
   2 inches in diameter will be possible with the more intense updrafts
   during the early to mid evening.

   Large-scale ascent will steadily increase across the central Plains
   this evening as the upper-level trough approaches. As a result,
   thunderstorm development will occur across much of Nebraska. Cold
   pool development is expected as a linear MCS moves quickly eastward
   across the central Plains. The MCS will become more organized as a
   40 to 50 kt jet strengthens across northern Kansas and southern
   Nebraska. Strengthening will also occur as the MCS moves into the
   extremely unstable airmass, currently located in eastern Nebraska
   and northwest Missouri. Damaging wind gusts will be likely along the
   leading edge of the MCS, with some wind gusts greater than 70 knots
   possible. Supercells that are embedded in the linear MCS may be able
   to produce very large hail. These rotating cells should also have a
   tornado threat.

   The linear MCS is expected to reach the mid to upper Mississippi
   Valley late in the period. A severe threat could continue into the
   early morning across parts of the mid Mississippi Valley where
   isolated wind damage and hail will be the primary threats.

   ...Eastern Seaboard...
   Water vapor currently shows an upper-level trough from the lower
   Great Lakes into the central Appalachians. Ahead of the trough, a
   moderately unstable airmass is in place along much of the Eastern
   Seaboard. Several small clusters of thunderstorms are ongoing from
   the Mid-Atlantic Coast south-southwestward into the far eastern
   Carolinas. Due to the instability combined with steep low-level
   lapse rates, a marginal wind-damage threat will exist for another
   hour or so this evening before cooling surface temperature mitigate
   the threat.

   ..Broyles.. 07/10/2021

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z