Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat May 06 2023 01:13:11 AWUS01 KWNH 060113 FFGMPD IAZ000-NEZ000-060710- Mesoscale Precipitation Discussion 0226 NWS Weather Prediction Center College Park MD 912 PM EDT Fri May 05 2023 Areas affected...south-central to eastern NE Concerning...Heavy rainfall...Flash flooding possible Valid 060111Z - 060710Z Summary...Rainfall rates of 1-2 in/hr will pose a risk for flash flooding across portions of south-central to eastern NE. The window of concern will extend through 07Z but the flash flood threat will diminish from west to east over time. Discussion...At 0030Z, GOES East water vapor imagery showed a negatively tilted shortwave trough axis extending from west-central WY into northeastern CO. A 70-100 kt jet near 300 mb extended from southern CA into eastern CO with the left exit region (upper divergence) located over the NE Panhandle along with strongly diffluent flow aloft. It is ahead of the advancing shortwave/jet max where a region of thunderstorms was translating ENE, extending from southwestern SD into western NE. Over southern NE, south of I-80 from WSW of LXN to 40 mi west of HJH, 3 or 4 supercells were located just north of a warm front/surface convergence axis within an environment characterized by MLCAPE of 500-1500 J/kg and precipitable water values at or about 1 inch. These cells were following Bunkers right movement toward the east at 10-15 kt and do not themselves pose a significant risk of flash flooding given their steady movement. Convection over western NE is likely to continue advancing toward the ENE, ahead of the advancing shortwave aloft. Increasing magnitude of the low level jet to just over 40 kt is expected from central KS into NE by 06Z, helping to transport low level moisture northward and increase MUCAPE into eastern NE to over 1000 J/kg (per recent RAP/HRRR forecasts). Some additional convective development will be possible ahead of the main advancing cluster currently over western NE given the increase in forcing. While a steady eastward movement of heavy rain cores are expected overnight, some short term training will be possible with rainfall rates of 1-2 in/hr. While the heaviest rain may fall over the Sand Hills, flash flood guidance is as low as 1-2 inches in an hour and 1.5 to 2.5 inches in 3 hours outside of the Sand Hills. Some of these values may be exceeded through 07Z, posing a risk for flash flooding. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7iaICugsV2s5NqeloB2RX5CavSgjYvOcHur0Q6oCPJ3fgE97w6o49Qxbb_s4AhVSSNr4= aoVBk2PpfLyqMdbqLZjaIqA$ for graphic product... ATTN...WFO...FSD...GID...GLD...LBF...OAX... ATTN...RFC...MBRFC...NWC... LAT...LON 42529736 42359650 41359594 40749658 40429750=20 40189837 40129992 40320117 41050166 41320089=20 41600024 41749945 41619867 41849817 42309793=20 =20=20=20=20=20=20=20=20=20=20=20=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .