Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Dec 09 2023 06:12:33 AWUS01 KWNH 090612 FFGMPD ARZ000-091110- Mesoscale Precipitation Discussion 1190 NWS Weather Prediction Center College Park MD 111 AM EST Sat Dec 09 2023 Areas affected...Central AR Concerning...Heavy rainfall...Flash flooding possible Valid 090610Z - 091110Z SUMMARY...An instance or two of flash flooding will be possible over the next few hours from locally training showers and thunderstorms. DISCUSSION...Radar imagery shows a band of heavy showers and thunderstorms tending to slowly grow upscale across areas of west-central AR just ahead of a cold front with a movement generally off to the east-northeast in alignment with the deeper layer west-southwest flow ahead of a rather strong and positively tilted upper trough advancing east over the Plains. A nose of MLCAPE values of 1000 to 1500+ J/kg is noted just ahead of the cold front and with a southwest low-level jet of 40+ kts helping to favor relatively strong moisture and instability transport into the region from the broader Arklatex. Overall, the PWs are not particularly high with values of 1.0 to 1.2 inches, but the latest MRMS data does show some of the stronger convective cells producing 1 to 2 inch/hour rainfall rates with aid from the low-level jet. Stronger upper-level jet energy rounding the base of the trough over the Plains will be arriving going through the remainder of the night, and this stronger forcing/divergence aloft coupled with the favorable instability pool ahead of advancing cold front should favor some additional bands of convection that will likely have a bit of a linear mode to them. Given the orientation to the deeper layer mean flow, there will be at least some concerns for locally training convective cells. The 00Z HREF guidance and recent HRRR runs have been quite bad in handling the level of convection that has already initiated, and it is possible given the available forcing that some additional upscale growth of convection may occur. Given the rainfall rates, and concerns for some training cells, some localized rainfall totals of 2 to 4 inches will be possible. An instance or two of flash flooding will be possible as some of these localized training convective bands evolve going through the remainder of the night. Some of the convection may get into the southern suburbs of the Little Rock metropolitan area, and so there will be at least some urban flooding considerations as this convection arrives over the next few hours. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6R1LpE4cTitJZnyM4u6KCakelDcO37ldz6wpL5L60w03K91SdRyGK25np8Ph1fe2JUeu= ab5qP23CoaS2gHgUDYv-8tE$ for graphic product... ATTN...WFO...LZK...SHV... ATTN...RFC...ABRFC...LMRFC...NWC... LAT...LON 35339234 35299143 34739114 34189190 33989301=20 33949379 34139412 34459406 34929339=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) .