SPC AC 220730

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0230 AM CDT Sun Sep 22 2019

   Valid 241200Z - 251200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
   IOWA...WESTERN WISCONSIN...AND SOUTHERN MINNESOTA...

   ...SUMMARY...
   Severe storms are possible Tuesday across much of Iowa, Wisconsin,
   and southern Minnesota, with isolated storms from parts of the
   central Plains to the Upper Great Lakes.

   ...Synopsis...
   An elongated upper jet will dive southeastward across the northern
   Plains and into the upper MS Valley on Tuesday, with significant
   cooling aloft and increasing shear. The strongest lift will focus
   over MN, IA and WI as a cold front collides with returning low-level
   moisture with at least mid 60s F dewpoints. The cold front will
   progress eastward toward northern IL by Wed morning, while western
   parts of the front stall from KS into the TX Panhandle.

   To the west, an upper low will continue southward across western AZ
   and into the northern Baja, maintaining a favorable environment for
   scattered storms over southern AZ and NM.

   ...Upper MS Valley to the central Plains...
   Most of the area will remain free of thunderstorms for much of the
   day as the moist plume becomes established and temperatures aloft
   cool. By around 00Z, storms are expected to form along the front
   from southern MN into IA and perhaps eastern NE, and will expand in
   coverage through the evening into WI. Strong deep-layer shear
   perpendicular to the front will favor supercells, with steep lapse
   rates aloft and around 200 m2/s2 ESRH favoring very large hail and
   perhaps a tornado or two.

   Farther south into KS, strong heating of a 65-70 F dewpoint air mass
   will lead to over 3000 J/kg MUCAPE, with isolated severe storms
   expected across central and eastern KS. Hail will be possible, with
   localized wind damage. Parts of this area may require a categorical
   upgrade in later outlooks once placement of potential storm clusters
   is more precise.

   ...Southern AZ and southwest NM...
   Scattered to numerous storms may be ongoing Tuesday morning over
   southern AZ and NM in association with the upper low. Pockets of
   destabilization may occur once again during the day, with isolated
   strong to severe storms possible capable of hail or localized wind
   damage.

   ..Jewell.. 09/22/2019

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   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z