Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Dec 11 2022 03:31:15 AWUS01 KWNH 110331 FFGMPD LAZ000-TXZ000-110910- Mesoscale Precipitation Discussion 1151 NWS Weather Prediction Center College Park MD 1030 PM EST Sat Dec 10 2022 Areas affected...Ext Southeast TX...Southwest LA... Concerning...Heavy rainfall...Flash flooding possible Valid 110330Z - 110910Z SUMMARY...Slow moving efficient cells pose localized flash flooding risk through overnight period. DISCUSSION...Regional RADAR and GOES-E 10.3um EIR loop denotes a cluster of stronger individual cells generally congealing into a slow moving complex. Strong overshooting tops dot the cirrus canopy like stones in a stream, indicative of cell rotation and slow forward propagation through the mean flow. Combined with localized isallobaric influenced moisture flux, cells continue to be very efficient rainfall producers. These cells reside along this morning's Gulf sea-breeze with higher theta-E and enhanced low level moisture. Tds are generally above 70F south of the weak boundary, with deeper layer flow is starting to increase to 20-25kts becoming convergent with the approach of the larger synoptic cold front dropping through E TX back to the Hill country. Given 1.75" of total PWAT and this flux convergence, rain rates of 2"/hr are associated with the rotating cells. Given forward motions are slowed to 5-10kts, this has allowed and is expected to continue through the overnight period as the best mesoscale forcing shifts eastward into SE LA. Goes-E WV also notes the core of slightly digging shortwave over the Hill country is aiding some weak diffluence at the entrance of the 50-70kt 3H jet. This should allow for favorable upstream redevelopment and potential for cells to repeat. In addition, weak confluent SE-NE streamers emanating across the Gulf, combined with frictional convergence have also sparked some isolated supercells along the Gulf coast. As the complex matures, weak cold pooling will allow for south-southeastward propagation, while these cells lift north producing a solid potential for cell mergers and highly localized short-bursts of rates over 2.5"/hr.=20 This will result in the highest probability of inducing rapid inundation flooding, but should be highly isolated. Still, the potential for slow moving cells with upstream development, as such these enhanced totals (4") should dot a broader 2-3" area from SE TX into Southwest LA. According to NASA SPoRT LIS Soil Moisture products, the region is slightly below average for soils; however given rates scattered flash flooding remains possible through to 09z. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-b5fSVmD9rHYbiAwxBlY1R7viMUaU4pFphm9cW-CzPPmz0mfZ2Q_LzDgcqaZ9VoT04J0= g5jih-Wah7ZpEWQHzRv2zrE$ for graphic product... ATTN...WFO...LCH...LIX...SHV... ATTN...RFC...LMRFC...WGRFC...NWC... LAT...LON 31589344 31439262 31019180 30799151 30389131=20 29929166 29929256 30059335 30289399 30679430=20 31109433 31499384=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) .