Sep 2, 2022 1630 UTC Day 1 Convective Outlook
Updated: Fri Sep 2 16:30:29 UTC 2022 (20220902 1630Z Day 1 shapefile | 20220902 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20220902 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 21,954 4,329,671 Phoenix, AZ...Mesa, AZ...Glendale, AZ...Chandler, AZ...Scottsdale, AZ...
MARGINAL 246,248 10,254,405 Las Vegas, NV...Tucson, AZ...Omaha, NE...Lincoln, NE...Henderson, NV...
Probabilistic Tornado Graphic
20220902 1630 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
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20220902 1630 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 12,670 4,081,667 Phoenix, AZ...Mesa, AZ...Glendale, AZ...Chandler, AZ...Scottsdale, AZ...
15 % 22,050 4,329,726 Phoenix, AZ...Mesa, AZ...Glendale, AZ...Chandler, AZ...Scottsdale, AZ...
5 % 245,389 10,256,385 Las Vegas, NV...Tucson, AZ...Omaha, NE...Lincoln, NE...Henderson, NV...
Probabilistic Large Hail Graphic
20220902 1630 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
5 % 124,064 4,989,763 Omaha, NE...Lincoln, NE...Rochester, MN...Sioux City, IA...Eau Claire, WI...
   SPC AC 021630

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1130 AM CDT Fri Sep 02 2022

   Valid 021630Z - 031200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   ARIZONA/LOWER COLORADO RIVER VALLEY...

   ...SUMMARY...
   Isolated severe thunderstorms are possible late this afternoon and
   evening over parts of central/southern Arizona and the Lower
   Colorado River Valley, and from the central Great Plains to the
   Upper Great Lakes.

   ...Arizona/Lower Colorado Valley...
   Visible satellite shows relatively cloud-free skies, which will be
   conducive for ample insolation/heating coincident with a relatively
   moist air mass, with prevalent 60s F surface dewpoints in the lower
   elevations of southern Arizona and middle 50s F dewpoints along the
   Mogollon Rim as of late morning. An increase in storm coverage as
   compared to yesterday seems probable.

   Easterly mid-level/steering winds are and will remain notably strong
   as the upper high builds to the north over the Great Basin/central
   Rockies. Upwards of 25-30 kt mid-level winds are plausible across
   the southern half of Arizona, which would be conducive for storm
   organization/upscale growth and propagation onto the lower
   elevations/desert floor and Lower Colorado River Valley. Initial
   discrete development over the higher terrain/near the Rim will pose
   a risk for localized severe wind gusts and marginally severe hail.
   However, a more organized/substantial wind threat may emerge with
   upscale-growing/MCS development by evening.

   ...Central Plains to Upper Great Lakes...
   The primary shortwave trough over northeast Manitoba will shift east
   across southern Hudson Bay/far northern Ontario, with the trailing
   part of this trough moving across the Upper Great Lakes. A weak
   mid-level trough will meander east across the Ozarks. In between
   these features, deep-layer shear will be enhanced across the central
   Great Plains owing to 25-35 kt mid-level north-northwesterly winds.
   Weaker deep-layer shear is anticipated with northeast extent along a
   cold front pushing southeastward across the Upper Midwest.

   A greater potential for scattered thunderstorms along the front
   should exist in the southeast Minnesota/northern Wisconsin/Upper
   Michigan vicinity given more pronounced low-level convergence and
   trailing influence of the Ontario trough. Multicell clusters mainly
   producing isolated damaging winds and perhaps marginally severe hail
   will be the primary threats.

   A more isolated thunderstorm coverage is anticipated into southeast
   Nebraska and northern Kansas, but given the greater vertical shear
   and nearly perpendicular orientation of mid-level flow with respect
   to the front, a few transient supercells embedded within a cluster
   or two may develop. Isolated severe wind and hail will be possible,
   with increasing MLCIN after dusk being detrimental for sustaining
   severe potential later into the evening.

   ..Guyer/Bentley.. 09/02/2022

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