Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 06 2024 02:12:18 AWUS01 KWNH 060212 FFGMPD WIZ000-ILZ000-MNZ000-IAZ000-060810- Mesoscale Precipitation Discussion 0815 NWS Weather Prediction Center College Park MD 1011 PM EDT Mon Aug 05 2024 Areas affected...Portions of the Upper Midwest Concerning...Heavy rainfall...Flash flooding possible Valid 060210Z - 060810Z SUMMARY...A strong MCS will be crossing through portions of the Upper Midwest overnight and will be capable of producing heavy to locally excessive rainfall. Given relatively moist antecedent conditions, some scattered instances of flash flooding will be possible. DISCUSSION...The mid-evening GOES-E IR satellite imagery shows a strong cold-topped MCS advancing east-southeast across portions of southeast MN through western WI. This activity is in association with a strong shortwave trough crossing the Upper Midwest with much of the convection elevated in nature and embedded along a strong instability gradient. This instability gradient is well-aligned with a northwest to southeast oriented front ahead of a low pressure center. MUCAPE values are as high as 2000 to 3000 J/kg in close proximity to the front, and there is a convergent southwest low-level jet of 30 to 40 kts that is supporting strong warm air advection with enhanced moisture and instability transport ahead of the approaching shortwave energy. Over the next several hours, the MCS should remain well-organized as it drops east-southeast across central and southern WI. There is some potential for this to lose sufficient latitude for areas of northeast IA and northern IL to get into at least the southern flank of the MCS where the nose of stronger low-level jet energy will be focused along with greater instability. Given the level of forcing and strongly favorable thermodynamics, the rainfall rates with the stronger storms should approach 1.5 to 2 inches/hour. The MCS is forward propagating which will tend to mitigate the rainfall totals a bit and lessen the flash flood threat, however, there may be sufficient levels of short-term training for some rainfall totals to reach 2 to 4 inches. These rainfall totals are generally consistent with the 12Z/18Z HREF guidance, but some of the HREF members have been notably too far to the north with the axis of heavier QPF. Accounting for the latest radar and satellite trends, the axis of heaviest rains should generally cross through central and southern WI. Given these heavier rains and relatively moist antecedent conditions, some scattered areas of flash flooding will be possible heading into the overnight hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6Xy1Phzf0oAGkics_WA3u_NjYByMyTtZvesibPASCzD23GFh8hpfxTUS6LpS93mB0VYD= FIYRE6yslEvoiacKC3wIEfs$ for graphic product... ATTN...WFO...ARX...DMX...DVN...GRB...LOT...MKX...MPX... ATTN...RFC...NCRFC...NWC... LAT...LON 44849099 44758960 44258794 43478736 42418736=20 42028812 42108932 42359101 42869246 43269285=20 43949200 44569188=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .